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Issue published January 3, 2017 Previous issue | Next issue

  • Volume 127, Issue 1
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  • Review Series
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Review Series
Inflammatory mechanisms linking obesity and metabolic disease
Alan R. Saltiel, Jerrold M. Olefsky
Alan R. Saltiel, Jerrold M. Olefsky
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):1-4. https://doi.org/10.1172/JCI92035.
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Inflammatory mechanisms linking obesity and metabolic disease

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Abstract

There are currently over 1.9 billion people who are obese or overweight, leading to a rise in related health complications, including insulin resistance, type 2 diabetes, cardiovascular disease, liver disease, cancer, and neurodegeneration. The finding that obesity and metabolic disorder are accompanied by chronic low-grade inflammation has fundamentally changed our view of the underlying causes and progression of obesity and metabolic syndrome. We now know that an inflammatory program is activated early in adipose expansion and during chronic obesity, permanently skewing the immune system to a proinflammatory phenotype, and we are beginning to delineate the reciprocal influence of obesity and inflammation. Reviews in this series examine the activation of the innate and adaptive immune system in obesity; inflammation within diabetic islets, brain, liver, gut, and muscle; the role of inflammation in fibrosis and angiogenesis; the factors that contribute to the initiation of inflammation; and therapeutic approaches to modulate inflammation in the context of obesity and metabolic syndrome.

Authors

Alan R. Saltiel, Jerrold M. Olefsky

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Role of innate and adaptive immunity in obesity-associated metabolic disease
Tracey McLaughlin, … , Lei Shen, Edgar Engleman
Tracey McLaughlin, … , Lei Shen, Edgar Engleman
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):5-13. https://doi.org/10.1172/JCI88876.
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Role of innate and adaptive immunity in obesity-associated metabolic disease

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Abstract

Chronic inflammation in adipose tissue, possibly related to adipose cell hypertrophy, hypoxia, and/or intestinal leakage of bacteria and their metabolic products, likely plays a critical role in the development of obesity-associated insulin resistance (IR). Cells of both the innate and adaptive immune system residing in adipose tissues, as well as in the intestine, participate in this process. Thus, M1 macrophages, IFN-γ–secreting Th1 cells, CD8+ T cells, and B cells promote IR, in part through secretion of proinflammatory cytokines. Conversely, eosinophils, Th2 T cells, type 2 innate lymphoid cells, and possibly Foxp3+ Tregs protect against IR through local control of inflammation.

Authors

Tracey McLaughlin, Shelley E. Ackerman, Lei Shen, Edgar Engleman

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Islet inflammation in type 2 diabetes and physiology
Kosei Eguchi, Ryozo Nagai
Kosei Eguchi, Ryozo Nagai
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):14-23. https://doi.org/10.1172/JCI88877.
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Islet inflammation in type 2 diabetes and physiology

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Abstract

The finding of islet inflammation in type 2 diabetes (T2D) and its involvement in β cell dysfunction has further highlighted the significance of inflammation in metabolic diseases. The number of intra-islet macrophages is increased in T2D, and these cells are the main source of proinflammatory cytokines within islets. Multiple human studies of T2D have shown that targeting islet inflammation has the potential to be an effective therapeutic strategy. In this Review we provide an overview of the cellular and molecular mechanisms by which islet inflammation develops and causes β cell dysfunction. We also emphasize the regulation and roles of macrophage polarity shift within islets in the context of T2D pathology and β cell health, which may have broad translational implications for therapeutics aimed at improving islet function.

Authors

Kosei Eguchi, Ryozo Nagai

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Hypothalamic inflammation in obesity and metabolic disease
Alexander Jais, Jens C. Brüning
Alexander Jais, Jens C. Brüning
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):24-32. https://doi.org/10.1172/JCI88878.
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Hypothalamic inflammation in obesity and metabolic disease

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Abstract

Over the last years, hypothalamic inflammation has been linked to the development and progression of obesity and its sequelae. There is accumulating evidence that this inflammation not only impairs energy balance but also contributes to obesity-associated insulin resistance. Elevated activation of key inflammatory mediators such as JNK and IκB kinase (IKK) occurs rapidly upon consumption of a high-fat diet, even prior to significant weight gain. This activation of hypothalamic inflammatory pathways results in the uncoupling of caloric intake and energy expenditure, fostering overeating and further weight gain. In addition, these inflammatory processes contribute to obesity-associated insulin resistance and deterioration of glucose metabolism via altered neurocircuit functions. An understanding of the contributions of different neuronal and non-neuronal cell types to hypothalamic inflammatory processes, and delineation of the differences and similarities between acute and chronic activation of these inflammatory pathways, will be critical for the development of novel therapeutic strategies for the treatment of obesity and metabolic syndrome.

Authors

Alexander Jais, Jens C. Brüning

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Immunologic impact of the intestine in metabolic disease
Daniel A. Winer, … , Helen J. Dranse, Tony K.T. Lam
Daniel A. Winer, … , Helen J. Dranse, Tony K.T. Lam
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):33-42. https://doi.org/10.1172/JCI88879.
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Immunologic impact of the intestine in metabolic disease

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Abstract

Obesity and diabetes are associated with increased chronic low-grade inflammation and elevated plasma glucose levels. Although inflammation in the fat and liver are established features of obesity-associated insulin resistance, the intestine is emerging as a new site for immunologic changes that affect whole-body metabolism. Specifically, microbial and dietary factors incurred by diet-induced obesity influence underlying innate and adaptive responses of the intestinal immune system. These responses affect the maintenance of the intestinal barrier, systemic inflammation, and glucose metabolism. In this Review we propose that an understanding of the changes to the intestinal immune system, and how these changes influence systemic immunity and glucose metabolism in a whole-body integrative and a neuronal-dependent network, will unveil novel intestinal pathologic and therapeutic targets for diabetes and obesity.

Authors

Daniel A. Winer, Shawn Winer, Helen J. Dranse, Tony K.T. Lam

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Skeletal muscle inflammation and insulin resistance in obesity
Huaizhu Wu, Christie M. Ballantyne
Huaizhu Wu, Christie M. Ballantyne
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):43-54. https://doi.org/10.1172/JCI88880.
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Skeletal muscle inflammation and insulin resistance in obesity

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Abstract

Obesity is associated with chronic inflammation, which contributes to insulin resistance and type 2 diabetes mellitus. Under normal conditions, skeletal muscle is responsible for the majority of insulin-stimulated whole-body glucose disposal; thus, dysregulation of skeletal muscle metabolism can strongly influence whole-body glucose homeostasis and insulin sensitivity. Increasing evidence suggests that inflammation occurs in skeletal muscle in obesity and is mainly manifested by increased immune cell infiltration and proinflammatory activation in intermyocellular and perimuscular adipose tissue. By secreting proinflammatory molecules, immune cells may induce myocyte inflammation, adversely regulate myocyte metabolism, and contribute to insulin resistance via paracrine effects. Increased influx of fatty acids and inflammatory molecules from other tissues, particularly visceral adipose tissue, can also induce muscle inflammation and negatively regulate myocyte metabolism, leading to insulin resistance.

Authors

Huaizhu Wu, Christie M. Ballantyne

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Liver inflammation and fibrosis
Yukinori Koyama, David A. Brenner
Yukinori Koyama, David A. Brenner
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):55-64. https://doi.org/10.1172/JCI88881.
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Liver inflammation and fibrosis

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Abstract

Chronic liver inflammation leads to fibrosis and cirrhosis, which is the 12th leading cause of death in the United States. Hepatocyte steatosis is a component of metabolic syndrome and insulin resistance. Hepatic steatosis may be benign or progress to hepatocyte injury and the initiation of inflammation, which activates immune cells. While Kupffer cells are the resident macrophage in the liver, inflammatory cells such as infiltrating macrophages, T lymphocytes, neutrophils, and DCs all contribute to liver inflammation. The inflammatory cells activate hepatic stellate cells, which are the major source of myofibroblasts in the liver. Here we review the initiation of inflammation in the liver, the liver inflammatory cells, and their crosstalk with myofibroblasts.

Authors

Yukinori Koyama, David A. Brenner

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The initiation of metabolic inflammation in childhood obesity
Kanakadurga Singer, Carey N. Lumeng
Kanakadurga Singer, Carey N. Lumeng
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):65-73. https://doi.org/10.1172/JCI88882.
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The initiation of metabolic inflammation in childhood obesity

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Abstract

An understanding of the events that initiate metabolic inflammation (metainflammation) can support the identification of targets for preventing metabolic disease and its negative effects on health. There is ample evidence demonstrating that the initiating events in obesity-induced inflammation start early in childhood. This has significant implications on our understanding of how early life events in childhood influence adult disease. In this Review we frame the initiating events of metainflammation in the context of child development and discuss what this reveals about the mechanisms by which this unique form of chronic inflammation is initiated and sustained into adulthood.

Authors

Kanakadurga Singer, Carey N. Lumeng

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The ominous triad of adipose tissue dysfunction: inflammation, fibrosis, and impaired angiogenesis
Clair Crewe, … , Yu Aaron An, Philipp E. Scherer
Clair Crewe, … , Yu Aaron An, Philipp E. Scherer
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):74-82. https://doi.org/10.1172/JCI88883.
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The ominous triad of adipose tissue dysfunction: inflammation, fibrosis, and impaired angiogenesis

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Abstract

There are three dominant contributors to the pathogenesis of dysfunctional adipose tissue (AT) in obesity: unresolved inflammation, inappropriate extracellular matrix (ECM) remodeling and insufficient angiogenic potential. The interactions of these processes during AT expansion reflect both a linear progression as well as feed-forward mechanisms. For example, both inflammation and inadequate angiogenic remodeling can drive fibrosis, which can in turn promote migration of immune cells into adipose depots and impede further angiogenesis. Therefore, the relationship between the members of this triad is complex but important for our understanding of the pathogenesis of obesity. Here we untangle some of these intricacies to highlight the contributions of inflammation, angiogenesis, and the ECM to both “healthy” and “unhealthy” AT expansion.

Authors

Clair Crewe, Yu Aaron An, Philipp E. Scherer

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Therapeutic approaches targeting inflammation for diabetes and associated cardiovascular risk
Allison B. Goldfine, Steven E. Shoelson
Allison B. Goldfine, Steven E. Shoelson
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):83-93. https://doi.org/10.1172/JCI88884.
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Therapeutic approaches targeting inflammation for diabetes and associated cardiovascular risk

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Abstract

Obesity-related sub-acute chronic inflammation has been associated with incident type 2 diabetes and atherosclerotic cardiovascular disease. Inflammation is increasingly considered to be a pathologic mediator of these commonly co-occurring diseases. A growing number of preclinical and clinical studies support the inflammatory hypothesis, but clinical trials to confirm the therapeutic potential to target inflammation to treat or prevent cardiometabolic conditions are still ongoing. There are multiple inflammatory signaling pathways. Regulation is complex, with substantial crosstalk across these multiple pathways. The activity of select pathways may be differentially regulated in different tissues. Pharmacologic approaches to diabetes management may have direct or indirect antiinflammatory effects, the latter potentially attributable to an improved metabolic state. Conversely, some antiinflammatory approaches may affect glucose metabolism and cardiovascular health. To date, clinical trials suggest that targeting one portion of the inflammatory cascade may differentially affect dysglycemia and atherothrombosis. Understanding the underlying biological processes may contribute to the development of safe and effective therapies, although a single approach may not be sufficient for optimal management of both metabolic and athrothrombotic disease states.

Authors

Allison B. Goldfine, Steven E. Shoelson

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Commentaries
β Cells led astray by transcription factors and the company they keep
Peter Thompson, Anil Bhushan
Peter Thompson, Anil Bhushan
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):94-97. https://doi.org/10.1172/JCI91304.
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β Cells led astray by transcription factors and the company they keep

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Abstract

Pancreatic β cells have one of the highest protein secretion burdens in the body, as these cells must synthesize and secrete insulin in proportion to postprandial rises in blood glucose. Remarkably, it is now becoming clear that adult β cells retain plasticity and can dedifferentiate into embryonic fates or adopt alternate islet endocrine cell identities. This property is especially important, because changes in cell fate alter β cell function and could form the basis for defects in insulin secretion that occur early in the pathogenesis of the most prevalent form of β cell dysfunction, type 2 diabetes. In this issue, three different studies provide complementary perspectives on how the transcription factors NK2 homeobox 2 (NKX2.2), paired box 6 (PAX6), and LIM domain–binding protein 1 (LDB1) serve to maintain mature adult β cell identity, revealing clues as to how adult β cells can partially dedifferentiate or become reprogrammed into other islet endocrine cells.

Authors

Peter Thompson, Anil Bhushan

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Impaired prohormone processing: a grand unified theory for features of Prader-Willi syndrome?
Joseph Polex-Wolf, … , Giles S.H. Yeo, Stephen O’Rahilly
Joseph Polex-Wolf, … , Giles S.H. Yeo, Stephen O’Rahilly
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):98-99. https://doi.org/10.1172/JCI91307.
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Impaired prohormone processing: a grand unified theory for features of Prader-Willi syndrome?

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Abstract

Prader-Willi syndrome (PWS) is a complex disorder that manifests with an array of phenotypes, such as hypotonia and difficulties in feeding during infancy and reduced energy expenditure, hyperphagia, and developmental delays later in life. While the genetic cause has long been known, it is still not clear how mutations at this locus produce this array of phenotypes. In this issue of the JCI, Burnett and colleagues used a comprehensive approach to gain insight into how PWS-associated mutations drive disease. Using neurons derived from PWS patient induced pluripotent stem cells (iPSCs) and mouse models, the authors provide evidence that neuroendocrine PWS-associated phenotypes may be linked to reduced expression of prohormone convertase 1 (PC1). While these compelling results support a critical role for PC1 deficiency in PWS, more work needs to be done to fully understand how and to what extent loss of this prohormone processing enzyme underlies disease manifestations in PWS patients.

Authors

Joseph Polex-Wolf, Giles S.H. Yeo, Stephen O’Rahilly

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Stored blood: how old is too old?
Janet S. Lee, Daniel B. Kim-Shapiro
Janet S. Lee, Daniel B. Kim-Shapiro
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):100-102. https://doi.org/10.1172/JCI91309.
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Stored blood: how old is too old?

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Abstract

Transfusion of rbc is a routine, often lifesaving procedure that depends on a stored supply of blood. In the US, 42 days is the maximum duration allowed for rbc storage; however, several lines of evidence indicate that patients that receive blood at the upper end of this storage limit are at a higher risk of morbidity and mortality. In this issue of the JCI, Rapido and colleagues evaluated the effects of transfusing one unit of blood close to the storage limit into healthy adults. Compared to those that received rbc stored for five weeks or less, those that received blood stored for six weeks showed several effects associated with increased harm, including disruption in iron handling, increased extravascular hemolysis, and the formation of circulating non–transferrin-bound iron. Together, the results of this study suggest that current maximum storage durations should be carefully reevaluated.

Authors

Janet S. Lee, Daniel B. Kim-Shapiro

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The interferon paradox: can inhibiting an antiviral mechanism advance an HIV cure?
Steven G. Deeks, … , Pamela M. Odorizzi, Rafick-Pierre Sekaly
Steven G. Deeks, … , Pamela M. Odorizzi, Rafick-Pierre Sekaly
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):103-105. https://doi.org/10.1172/JCI91916.
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The interferon paradox: can inhibiting an antiviral mechanism advance an HIV cure?

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Abstract

While antiretroviral therapy (ART) has improved the quality of life and increased the life span of many HIV-infected individuals, this therapeutic strategy has several limitations, including a lack of efficacy in fully restoring immune function and a requirement for life-long treatment. Two studies in this issue of the JCI use a humanized mouse model and demonstrate that type I interferon (IFN) is induced early during HIV infection and that type I IFN–associated gene signatures persist, even during ART. Importantly, blockade of type I IFN improved immune function, reduced the HIV reservoir, and caused a delay in viral rebound after ART interruption. Together, these two studies support further evaluation of IFN blockade as a supplement to ART.

Authors

Steven G. Deeks, Pamela M. Odorizzi, Rafick-Pierre Sekaly

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Research Articles
Randomized trial of calcipotriol combined with 5-fluorouracil for skin cancer precursor immunotherapy
Trevor J. Cunningham, … , Lynn A. Cornelius, Shadmehr Demehri
Trevor J. Cunningham, … , Lynn A. Cornelius, Shadmehr Demehri
Published November 21, 2016
Citation Information: J Clin Invest. 2017;127(1):106-116. https://doi.org/10.1172/JCI89820.
View: Text | PDF Clinical Research and Public Health

Randomized trial of calcipotriol combined with 5-fluorouracil for skin cancer precursor immunotherapy

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Abstract

BACKGROUND. Actinic keratosis is a precursor to cutaneous squamous cell carcinoma. Long treatment durations and severe side effects have limited the efficacy of current actinic keratosis treatments. Thymic stromal lymphopoietin (TSLP) is an epithelium-derived cytokine that induces a robust antitumor immunity in barrier-defective skin. Here, we investigated the efficacy of calcipotriol, a topical TSLP inducer, in combination with 5-fluorouracil (5-FU) as an immunotherapy for actinic keratosis.

METHODS. The mechanism of calcipotriol action against skin carcinogenesis was examined in genetically engineered mouse models. The efficacy and safety of 0.005% calcipotriol ointment combined with 5% 5-FU cream were compared with Vaseline plus 5-FU for the field treatment of actinic keratosis in a randomized, double-blind clinical trial involving 131 participants. The assigned treatment was self-applied to the entirety of the qualified anatomical sites (face, scalp, and upper extremities) twice daily for 4 consecutive days. The percentage of reduction in the number of actinic keratoses (primary outcome), local skin reactions, and immune activation parameters were assessed.

RESULTS. Calcipotriol suppressed skin cancer development in mice in a TSLP-dependent manner. Four-day application of calcipotriol plus 5-FU versus Vaseline plus 5-FU led to an 87.8% versus 26.3% mean reduction in the number of actinic keratoses in participants (P < 0.0001). Importantly, calcipotriol plus 5-FU treatment induced TSLP, HLA class II, and natural killer cell group 2D (NKG2D) ligand expression in the lesional keratinocytes associated with a marked CD4+ T cell infiltration, which peaked on days 10–11 after treatment, without pain, crusting, or ulceration.

CONCLUSION. Our findings demonstrate the synergistic effects of calcipotriol and 5-FU treatment in optimally activating a CD4+ T cell–mediated immunity against actinic keratoses and, potentially, cancers of the skin and other organs.

TRIAL REGISTRATION. ClinicalTrials.gov NCT02019355.

FUNDING. Not applicable (investigator-initiated clinical trial).

Authors

Trevor J. Cunningham, Mary Tabacchi, Jean-Pierre Eliane, Sara Moradi Tuchayi, Sindhu Manivasagam, Hengameh Mirzaalian, Ahu Turkoz, Raphael Kopan, Andras Schaffer, Arturo P. Saavedra, Michael Wallendorf, Lynn A. Cornelius, Shadmehr Demehri

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Epithelial-to-mesenchymal transition drives a pro-metastatic Golgi compaction process through scaffolding protein PAQR11
Xiaochao Tan, … , Yanzhuang Wang, Jonathan M. Kurie
Xiaochao Tan, … , Yanzhuang Wang, Jonathan M. Kurie
Published November 21, 2016
Citation Information: J Clin Invest. 2017;127(1):117-131. https://doi.org/10.1172/JCI88736.
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Epithelial-to-mesenchymal transition drives a pro-metastatic Golgi compaction process through scaffolding protein PAQR11

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Abstract

Tumor cells gain metastatic capacity through a Golgi phosphoprotein 3–dependent (GOLPH3-dependent) Golgi membrane dispersal process that drives the budding and transport of secretory vesicles. Whether Golgi dispersal underlies the pro-metastatic vesicular trafficking that is associated with epithelial-to-mesenchymal transition (EMT) remains unclear. Here, we have shown that, rather than causing Golgi dispersal, EMT led to the formation of compact Golgi organelles with improved ribbon linking and cisternal stacking. Ectopic expression of the EMT-activating transcription factor ZEB1 stimulated Golgi compaction and relieved microRNA-mediated repression of the Golgi scaffolding protein PAQR11. Depletion of PAQR11 dispersed Golgi organelles and impaired anterograde vesicle transport to the plasma membrane as well as retrograde vesicle tethering to the Golgi. The N-terminal scaffolding domain of PAQR11 was associated with key regulators of Golgi compaction and vesicle transport in pull-down assays and was required to reconstitute Golgi compaction in PAQR11-deficient tumor cells. Finally, high PAQR11 levels were correlated with EMT and shorter survival in human cancers, and PAQR11 was found to be essential for tumor cell migration and metastasis in EMT-driven lung adenocarcinoma models. We conclude that EMT initiates a PAQR11-mediated Golgi compaction process that drives metastasis.

Authors

Xiaochao Tan, Priyam Banerjee, Hou-Fu Guo, Stephen Ireland, Daniela Pankova, Young-ho Ahn, Irodotos Michail Nikolaidis, Xin Liu, Yanbin Zhao, Yongming Xue, Alan R. Burns, Jonathon Roybal, Don L. Gibbons, Tomasz Zal, Chad J. Creighton, Daniel Ungar, Yanzhuang Wang, Jonathan M. Kurie

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Inhibiting mitochondrial respiration prevents cancer in a mouse model of Li-Fraumeni syndrome
Ping-yuan Wang, … , Antonio Tito Fojo, Paul M. Hwang
Ping-yuan Wang, … , Antonio Tito Fojo, Paul M. Hwang
Published November 21, 2016
Citation Information: J Clin Invest. 2017;127(1):132-136. https://doi.org/10.1172/JCI88668.
View: Text | PDF Brief Report

Inhibiting mitochondrial respiration prevents cancer in a mouse model of Li-Fraumeni syndrome

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Abstract

Li-Fraumeni syndrome (LFS) is a cancer predisposition disorder caused by germline mutations in TP53 that can lead to increased mitochondrial metabolism in patients. However, the implications of altered mitochondrial function for tumorigenesis in LFS are unclear. Here, we have reported that genetic or pharmacologic disruption of mitochondrial respiration improves cancer-free survival in a mouse model of LFS that expresses mutant p53. Mechanistically, inhibition of mitochondrial function increased autophagy and decreased the aberrant proliferation signaling caused by mutant p53. In a pilot study, LFS patients treated with metformin exhibited decreases in mitochondrial activity concomitant with activation of antiproliferation signaling, thus reproducing the effects of disrupting mitochondrial function observed in LFS mice. These observations indicate that a commonly prescribed diabetic medicine can restrain mitochondrial metabolism and tumorigenesis in an LFS model, supporting its further consideration for cancer prevention in LFS patients.

Authors

Ping-yuan Wang, Jie Li, Farzana L. Walcott, Ju-Gyeong Kang, Matthew F. Starost, S. Lalith Talagala, Jie Zhuang, Ji-Hoon Park, Rebecca D. Huffstutler, Christina M. Bryla, Phuong L. Mai, Michael Pollak, Christina M. Annunziata, Sharon A. Savage, Antonio Tito Fojo, Paul M. Hwang

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Hippo signaling interactions with Wnt/β-catenin and Notch signaling repress liver tumorigenesis
Wantae Kim, … , Bin Gao, Yingzi Yang
Wantae Kim, … , Bin Gao, Yingzi Yang
Published November 21, 2016
Citation Information: J Clin Invest. 2017;127(1):137-152. https://doi.org/10.1172/JCI88486.
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Hippo signaling interactions with Wnt/β-catenin and Notch signaling repress liver tumorigenesis

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Abstract

Malignant tumors develop through multiple steps of initiation and progression, and tumor initiation is of singular importance in tumor prevention, diagnosis, and treatment. However, the molecular mechanism whereby a signaling network of interacting pathways restrains proliferation in normal cells and prevents tumor initiation is still poorly understood. Here, we have reported that the Hippo, Wnt/β-catenin, and Notch pathways form an interacting network to maintain liver size and suppress hepatocellular carcinoma (HCC). Ablation of the mammalian Hippo kinases Mst1 and Mst2 in liver led to rapid HCC formation and activated Yes-associated protein/WW domain containing transcription regulator 1 (YAP/TAZ), STAT3, Wnt/β-catenin, and Notch signaling. Previous work has shown that abnormal activation of these downstream pathways can lead to HCC. Rigorous genetic experiments revealed that Notch signaling forms a positive feedback loop with the Hippo signaling effector YAP/TAZ to promote severe hepatomegaly and rapid HCC initiation and progression. Surprisingly, we found that Wnt/β-catenin signaling activation suppressed HCC formation by inhibiting the positive feedback loop between YAP/TAZ and Notch signaling. Furthermore, we found that STAT3 in hepatocytes is dispensable for HCC formation when mammalian sterile 20–like kinase 1 and 2 (Mst1 and Mst2) were removed. The molecular network we have identified provides insights into HCC molecular classifications and therapeutic developments for the treatment of liver tumors caused by distinct genetic mutations.

Authors

Wantae Kim, Sanjoy Kumar Khan, Jelena Gvozdenovic-Jeremic, Youngeun Kim, Jason Dahlman, Hanjun Kim, Ogyi Park, Tohru Ishitani, Eek-hoon Jho, Bin Gao, Yingzi Yang

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Dual modulation of MCL-1 and mTOR determines the response to sunitinib
Mohamed Elgendy, … , Giuseppe Renne, Saverio Minucci
Mohamed Elgendy, … , Giuseppe Renne, Saverio Minucci
Published November 28, 2016
Citation Information: J Clin Invest. 2017;127(1):153-168. https://doi.org/10.1172/JCI84386.
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Dual modulation of MCL-1 and mTOR determines the response to sunitinib

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Abstract

Most patients who initially respond to treatment with the multi–tyrosine kinase inhibitor sunitinib eventually relapse. Therefore, developing a deeper understanding of the contribution of sunitinib’s numerous targets to the clinical response or to resistance is crucial. Here, we have shown that cancer cells respond to clinically relevant doses of sunitinib by enhancing the stability of the antiapoptotic protein MCL-1 and inducing mTORC1 signaling, thus evoking little cytotoxicity. Inhibition of MCL-1 or mTORC1 signaling sensitized cells to clinically relevant doses of sunitinib in vitro and was synergistic with sunitinib in impairing tumor growth in vivo, indicating that these responses are triggered as prosurvival mechanisms that enable cells to tolerate the cytotoxic effects of sunitinib. Furthermore, higher doses of sunitinib were cytotoxic, triggered a decline in MCL-1 levels, and inhibited mTORC1 signaling. Mechanistically, we determined that sunitinib modulates MCL-1 stability by affecting its proteasomal degradation. Dual modulation of MCL-1 stability at different dose ranges of sunitinib was due to differential effects on ERK and GSK3β activity, and the latter also accounted for dual modulation of mTORC1 activity. Finally, comparison of patient samples prior to and following sunitinib treatment suggested that increases in MCL-1 levels and mTORC1 activity correlate with resistance to sunitinib in patients.

Authors

Mohamed Elgendy, Amal Kamal Abdel-Aziz, Salvatore Lorenzo Renne, Viviana Bornaghi, Giuseppe Procopio, Maurizio Colecchia, Ravindran Kanesvaran, Chee Keong Toh, Daniela Bossi, Isabella Pallavicini, Jose Luis Perez-Gracia, Maria Dolores Lozano, Valeria Giandomenico, Ciro Mercurio, Luisa Lanfrancone, Nicola Fazio, Franco Nole, Bin Tean Teh, Giuseppe Renne, Saverio Minucci

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Accelerated resolution of inflammation underlies sex differences in inflammatory responses in humans
Krishnaraj S. Rathod, … , Jesmond Dalli, Amrita Ahluwalia
Krishnaraj S. Rathod, … , Jesmond Dalli, Amrita Ahluwalia
Published November 28, 2016
Citation Information: J Clin Invest. 2017;127(1):169-181. https://doi.org/10.1172/JCI89429.
View: Text | PDF | Corrigendum Clinical Research and Public Health

Accelerated resolution of inflammation underlies sex differences in inflammatory responses in humans

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Abstract

BACKGROUND. Cardiovascular disease occurs at lower incidence in premenopausal females compared with age-matched males. This variation may be linked to sex differences in inflammation. We prospectively investigated whether inflammation and components of the inflammatory response are altered in females compared with males. METHODS. We performed 2 clinical studies in healthy volunteers. In 12 men and 12 women, we assessed systemic inflammatory markers and vascular function using brachial artery flow-mediated dilation (FMD). In a further 8 volunteers of each sex, we assessed FMD response to glyceryl trinitrate (GTN) at baseline and at 8 hours and 32 hours after typhoid vaccine. In a separate study in 16 men and 16 women, we measured inflammatory exudate mediators and cellular recruitment in cantharidin-induced skin blisters at 24 and 72 hours. RESULTS. Typhoid vaccine induced mild systemic inflammation at 8 hours, reflected by increased white cell count in both sexes. Although neutrophil numbers at baseline and 8 hours were greater in females, the neutrophils were less activated. Systemic inflammation caused a decrease in FMD in males, but an increase in females, at 8 hours. In contrast, GTN response was not altered in either sex after vaccine. At 24 hours, cantharidin formed blisters of similar volume in both sexes; however, at 72 hours, blisters had only resolved in females. Monocyte and leukocyte counts were reduced, and the activation state of all major leukocytes was lower, in blisters of females. This was associated with enhanced levels of the resolving lipids, particularly D-resolvin. CONCLUSIONS. Our findings suggest that female sex protects against systemic inflammation-induced endothelial dysfunction. This effect is likely due to accelerated resolution of inflammation compared with males, specifically via neutrophils, mediated by an elevation of the D-resolvin pathway. TRIAL REGISTRATION. ClinicalTrials.gov NCT01582321 and NRES: City Road and Hampstead Ethics Committee: 11/LO/2038. FUNDING. The authors were funded by multiple sources, including the National Institute for Health Research, the British Heart Foundation, and the European Research Council.

Authors

Krishnaraj S. Rathod, Vikas Kapil, Shanti Velmurugan, Rayomand S. Khambata, Umme Siddique, Saima Khan, Sven Van Eijl, Lorna C. Gee, Jascharanpreet Bansal, Kavi Pitrola, Christopher Shaw, Fulvio D’Acquisto, Romain A. Colas, Federica Marelli-Berg, Jesmond Dalli, Amrita Ahluwalia

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Inhibition of the GAS6/AXL pathway augments the efficacy of chemotherapies
Mihalis S. Kariolis, … , Jennifer R. Cochran, Amato J. Giaccia
Mihalis S. Kariolis, … , Jennifer R. Cochran, Amato J. Giaccia
Published November 28, 2016
Citation Information: J Clin Invest. 2017;127(1):183-198. https://doi.org/10.1172/JCI85610.
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Inhibition of the GAS6/AXL pathway augments the efficacy of chemotherapies

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Abstract

The AXL receptor and its activating ligand, growth arrest–specific 6 (GAS6), are important drivers of metastasis and therapeutic resistance in human cancers. Given the critical roles that GAS6 and AXL play in refractory disease, this signaling axis represents an attractive target for therapeutic intervention. However, the strong picomolar binding affinity between GAS6 and AXL and the promiscuity of small molecule inhibitors represent important challenges faced by current anti-AXL therapeutics. Here, we have addressed these obstacles by engineering a second-generation, high-affinity AXL decoy receptor with an apparent affinity of 93 femtomolar to GAS6. Our decoy receptor, MYD1-72, profoundly inhibited disease progression in aggressive preclinical models of human cancers and induced cell killing in leukemia cells. When directly compared with the most advanced anti-AXL small molecules in the clinic, MYD1-72 achieved superior antitumor efficacy while displaying no toxicity. Moreover, we uncovered a relationship between AXL and the cellular response to DNA damage whereby abrogation of AXL signaling leads to accumulation of the DNA-damage markers γH2AX, 53BP1, and RAD51. MYD1-72 exploited this relationship, leading to improvements upon the therapeutic index of current standard-of-care chemotherapies in preclinical models of advanced pancreatic and ovarian cancer.

Authors

Mihalis S. Kariolis, Yu Rebecca Miao, Anh Diep, Shannon E. Nash, Monica M. Olcina, Dadi Jiang, Douglas S. Jones II, Shiven Kapur, Irimpan I. Mathews, Albert C. Koong, Erinn B. Rankin, Jennifer R. Cochran, Amato J. Giaccia

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VEGF regulates local inhibitory complement proteins in the eye and kidney
Lindsay S. Keir, … , Moin A. Saleem, Martin Friedlander
Lindsay S. Keir, … , Moin A. Saleem, Martin Friedlander
Published December 5, 2016
Citation Information: J Clin Invest. 2017;127(1):199-214. https://doi.org/10.1172/JCI86418.
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VEGF regulates local inhibitory complement proteins in the eye and kidney

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Abstract

Outer retinal and renal glomerular functions rely on specialized vasculature maintained by VEGF that is produced by neighboring epithelial cells, the retinal pigment epithelium (RPE) and podocytes, respectively. Dysregulation of RPE- and podocyte-derived VEGF is associated with neovascularization in wet age-related macular degeneration (ARMD), choriocapillaris degeneration, and glomerular thrombotic microangiopathy (TMA). Since complement activation and genetic variants in inhibitory complement factor H (CFH) are also features of both ARMD and TMA, we hypothesized that VEGF and CFH interact. Here, we demonstrated that VEGF inhibition decreases local CFH and other complement regulators in the eye and kidney through reduced VEGFR2/PKC-α/CREB signaling. Patient podocytes and RPE cells carrying disease-associated CFH genetic variants had more alternative complement pathway deposits than controls. These deposits were increased by VEGF antagonism, a common wet ARMD treatment, suggesting that VEGF inhibition could reduce cellular complement regulatory capacity. VEGF antagonism also increased markers of endothelial cell activation, which was partially reduced by genetic complement inhibition. Together, these results suggest that VEGF protects the retinal and glomerular microvasculature, not only through VEGFR2-mediated vasculotrophism, but also through modulation of local complement proteins that could protect against complement-mediated damage. Though further study is warranted, these findings could be relevant for patients receiving VEGF antagonists.

Authors

Lindsay S. Keir, Rachel Firth, Lyndsey Aponik, Daniel Feitelberg, Susumu Sakimoto, Edith Aguilar, Gavin I. Welsh, Anna Richards, Yoshihiko Usui, Simon C. Satchell, Valeryia Kuzmuk, Richard J. Coward, Jonathan Goult, Katherine R. Bull, Ruchi Sharma, Kapil Bharti, Peter D. Westenskow, Iacovos P. Michael, Moin A. Saleem, Martin Friedlander

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LIM domain–binding 1 maintains the terminally differentiated state of pancreatic β cells
Benjamin N. Ediger, … , Catherine Lee May, Doris A. Stoffers
Benjamin N. Ediger, … , Catherine Lee May, Doris A. Stoffers
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):215-229. https://doi.org/10.1172/JCI88016.
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LIM domain–binding 1 maintains the terminally differentiated state of pancreatic β cells

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Abstract

The recognition of β cell dedifferentiation in type 2 diabetes raises the translational relevance of mechanisms that direct and maintain β cell identity. LIM domain–binding protein 1 (LDB1) nucleates multimeric transcriptional complexes and establishes promoter-enhancer looping, thereby directing fate assignment and maturation of progenitor populations. Many terminally differentiated endocrine cell types, however, remain enriched for LDB1, but its role is unknown. Here, we have demonstrated a requirement for LDB1 in maintaining the terminally differentiated status of pancreatic β cells. Inducible ablation of LDB1 in mature β cells impaired insulin secretion and glucose homeostasis. Transcriptomic analysis of LDB1-depleted β cells revealed the collapse of the terminally differentiated gene program, indicated by a loss of β cell identity genes and induction of the endocrine progenitor factor neurogenin 3 (NEUROG3). Lineage tracing confirmed that LDB1-depleted, insulin-negative β cells express NEUROG3 but do not adopt alternate endocrine cell fates. In primary mouse islets, LDB1 and its LIM homeodomain–binding partner islet 1 (ISL1) were coenriched at chromatin sites occupied by pancreatic and duodenal homeobox 1 (PDX1), NK6 homeobox 1 (NKX6.1), forkhead box A2 (FOXA2), and NK2 homeobox 2 (NKX2.2) — factors that co-occupy active enhancers in 3D chromatin domains in human islets. Indeed, LDB1 was enriched at active enhancers in human islets. Thus, LDB1 maintains the terminally differentiated state of β cells and is a component of active enhancers in both murine and human islets.

Authors

Benjamin N. Ediger, Hee-Woong Lim, Christine Juliana, David N. Groff, LaQueena T. Williams, Giselle Dominguez, Jin-Hua Liu, Brandon L. Taylor, Erik R. Walp, Vasumathi Kameswaran, Juxiang Yang, Chengyang Liu, Chad S. Hunter, Klaus H. Kaestner, Ali Naji, Changhong Li, Maike Sander, Roland Stein, Lori Sussel, Kyoung-Jae Won, Catherine Lee May, Doris A. Stoffers

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PAX6 maintains β cell identity by repressing genes of alternative islet cell types
Avital Swisa, … , Ruth Ashery-Padan, Yuval Dor
Avital Swisa, … , Ruth Ashery-Padan, Yuval Dor
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):230-243. https://doi.org/10.1172/JCI88015.
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PAX6 maintains β cell identity by repressing genes of alternative islet cell types

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Abstract

Type 2 diabetes is thought to involve a compromised β cell differentiation state, but the mechanisms underlying this dysfunction remain unclear. Here, we report a key role for the TF PAX6 in the maintenance of adult β cell identity and function. PAX6 was downregulated in β cells of diabetic db/db mice and in WT mice treated with an insulin receptor antagonist, revealing metabolic control of expression. Deletion of Pax6 in β cells of adult mice led to lethal hyperglycemia and ketosis that were attributed to loss of β cell function and expansion of α cells. Lineage-tracing, transcriptome, and chromatin analyses showed that PAX6 is a direct activator of β cell genes, thus maintaining mature β cell function and identity. In parallel, we found that PAX6 binds promoters and enhancers to repress alternative islet cell genes including ghrelin, glucagon, and somatostatin. Chromatin analysis and shRNA-mediated gene suppression experiments indicated a similar function of PAX6 in human β cells. We conclude that reduced expression of PAX6 in metabolically stressed β cells may contribute to β cell failure and α cell dysfunction in diabetes.

Authors

Avital Swisa, Dana Avrahami, Noa Eden, Jia Zhang, Eseye Feleke, Tehila Dahan, Yamit Cohen-Tayar, Miri Stolovich-Rain, Klaus H. Kaestner, Benjamin Glaser, Ruth Ashery-Padan, Yuval Dor

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Pancreatic β cell identity requires continual repression of non–β cell programs
Giselle Domínguez Gutiérrez, … , Klaus H. Kaestner, Lori Sussel
Giselle Domínguez Gutiérrez, … , Klaus H. Kaestner, Lori Sussel
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):244-259. https://doi.org/10.1172/JCI88017.
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Pancreatic β cell identity requires continual repression of non–β cell programs

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Abstract

Loss of β cell identity, the presence of polyhormonal cells, and reprogramming are emerging as important features of β cell dysfunction in patients with type 1 and type 2 diabetes. In this study, we have demonstrated that the transcription factor NKX2.2 is essential for the active maintenance of adult β cell identity as well as function. Deletion of Nkx2.2 in β cells caused rapid onset of a diabetic phenotype in mice that was attributed to loss of insulin and downregulation of many β cell functional genes. Concomitantly, NKX2.2-deficient murine β cells acquired non–β cell endocrine features, resulting in populations of completely reprogrammed cells and bihormonal cells that displayed hybrid endocrine cell morphological characteristics. Molecular analysis in mouse and human islets revealed that NKX2.2 is a conserved master regulatory protein that controls the acquisition and maintenance of a functional, monohormonal β cell identity by directly activating critical β cell genes and actively repressing genes that specify the alternative islet endocrine cell lineages. This study demonstrates the highly volatile nature of the β cell, indicating that acquiring and sustaining β cell identity and function requires not only active maintaining of the expression of genes involved in β cell function, but also continual repression of closely related endocrine gene programs.

Authors

Giselle Domínguez Gutiérrez, Aaron S. Bender, Vincenzo Cirulli, Teresa L. Mastracci, Stephen M. Kelly, Aristotelis Tsirigos, Klaus H. Kaestner, Lori Sussel

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Targeting type I interferon–mediated activation restores immune function in chronic HIV infection
Anjie Zhen, … , David G. Brooks, Scott G. Kitchen
Anjie Zhen, … , David G. Brooks, Scott G. Kitchen
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):260-268. https://doi.org/10.1172/JCI89488.
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Targeting type I interferon–mediated activation restores immune function in chronic HIV infection

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Abstract

Chronic immune activation, immunosuppression, and T cell exhaustion are hallmarks of HIV infection, yet the mechanisms driving these processes are unclear. Chronic activation can be a driving force in immune exhaustion, and type I interferons (IFN-I) are emerging as critical components underlying ongoing activation in HIV infection. Here, we have tested the effect of blocking IFN-I signaling on T cell responses and virus replication in a murine model of chronic HIV infection. Using HIV-infected humanized mice, we demonstrated that in vivo blockade of IFN-I signaling during chronic HIV infection diminished HIV-driven immune activation, decreased T cell exhaustion marker expression, restored HIV-specific CD8 T cell function, and led to decreased viral replication. Antiretroviral therapy (ART) in combination with IFN-I blockade accelerated viral suppression, further decreased viral loads, and reduced the persistently infected HIV reservoir compared with ART treatment alone. Our data suggest that blocking IFN-I signaling in conjunction with ART treatment can restore immune function and may reduce viral reservoirs during chronic HIV infection, providing validation for IFN-I blockade as a potential therapy for HIV infection.

Authors

Anjie Zhen, Valerie Rezek, Cindy Youn, Brianna Lam, Nelson Chang, Jonathan Rick, Mayra Carrillo, Heather Martin, Saro Kasparian, Philip Syed, Nicholas Rice, David G. Brooks, Scott G. Kitchen

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Blocking type I interferon signaling enhances T cell recovery and reduces HIV-1 reservoirs
Liang Cheng, … , Lishan Su, Liguo Zhang
Liang Cheng, … , Lishan Su, Liguo Zhang
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):269-279. https://doi.org/10.1172/JCI90745.
View: Text | PDF Concise Communication

Blocking type I interferon signaling enhances T cell recovery and reduces HIV-1 reservoirs

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Abstract

Despite the efficient suppression of HIV-1 replication that can be achieved with combined antiretroviral therapy (cART), low levels of type I interferon (IFN-I) signaling persist in some individuals. This sustained signaling may impede immune recovery and foster viral persistence. Here we report studies using a monoclonal antibody to block IFN-α/β receptor (IFNAR) signaling in humanized mice (hu-mice) that were persistently infected with HIV-1. We discovered that effective cART restored the number of human immune cells in HIV-1–infected hu-mice but did not rescue their immune hyperactivation and dysfunction. IFNAR blockade fully reversed HIV-1–induced immune hyperactivation and rescued anti–HIV-1 immune responses in T cells from HIV-1–infected hu-mice. Finally, we found that IFNAR blockade in the presence of cART reduced the size of HIV-1 reservoirs in lymphoid tissues and delayed HIV-1 rebound after cART cessation in the HIV-1–infected hu-mice. We conclude that low levels of IFN-I signaling contribute to HIV-1–associated immune dysfunction and foster HIV-1 persistence in cART-treated hosts. Our results suggest that blocking IFNAR may provide a potential strategy to enhance immune recovery and reduce HIV-1 reservoirs in individuals with sustained elevations in IFN-I signaling during suppressive cART.

Authors

Liang Cheng, Jianping Ma, Jingyun Li, Dan Li, Guangming Li, Feng Li, Qing Zhang, Haisheng Yu, Fumihiko Yasui, Chaobaihui Ye, Li-Chung Tsao, Zhiyuan Hu, Lishan Su, Liguo Zhang

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TGF-β1 modulates microglial phenotype and promotes recovery after intracerebral hemorrhage
Roslyn A. Taylor, … , J. Christopher Love, Lauren H. Sansing
Roslyn A. Taylor, … , J. Christopher Love, Lauren H. Sansing
Published November 28, 2016
Citation Information: J Clin Invest. 2017;127(1):280-292. https://doi.org/10.1172/JCI88647.
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TGF-β1 modulates microglial phenotype and promotes recovery after intracerebral hemorrhage

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Abstract

Intracerebral hemorrhage (ICH) is a devastating form of stroke that results from the rupture of a blood vessel in the brain, leading to a mass of blood within the brain parenchyma. The injury causes a rapid inflammatory reaction that includes activation of the tissue-resident microglia and recruitment of blood-derived macrophages and other leukocytes. In this work, we investigated the specific responses of microglia following ICH with the aim of identifying pathways that may aid in recovery after brain injury. We used longitudinal transcriptional profiling of microglia in a murine model to determine the phenotype of microglia during the acute and resolution phases of ICH in vivo and found increases in TGF-β1 pathway activation during the resolution phase. We then confirmed that TGF-β1 treatment modulated inflammatory profiles of microglia in vitro. Moreover, TGF-β1 treatment following ICH decreased microglial Il6 gene expression in vivo and improved functional outcomes in the murine model. Finally, we observed that patients with early increases in plasma TGF-β1 concentrations had better outcomes 90 days after ICH, confirming the role of TGF-β1 in functional recovery from ICH. Taken together, our data show that TGF-β1 modulates microglia-mediated neuroinflammation after ICH and promotes functional recovery, suggesting that TGF-β1 may be a therapeutic target for acute brain injury.

Authors

Roslyn A. Taylor, Che-Feng Chang, Brittany A. Goods, Matthew D. Hammond, Brian Mac Grory, Youxi Ai, Arthur F. Steinschneider, Stephen C. Renfroe, Michael H. Askenase, Louise D. McCullough, Scott E. Kasner, Michael T. Mullen, David A. Hafler, J. Christopher Love, Lauren H. Sansing

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Deficiency in prohormone convertase PC1 impairs prohormone processing in Prader-Willi syndrome
Lisa C. Burnett, … , Dieter Egli, Rudolph L. Leibel
Lisa C. Burnett, … , Dieter Egli, Rudolph L. Leibel
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):293-305. https://doi.org/10.1172/JCI88648.
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Deficiency in prohormone convertase PC1 impairs prohormone processing in Prader-Willi syndrome

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Abstract

Prader-Willi syndrome (PWS) is caused by a loss of paternally expressed genes in an imprinted region of chromosome 15q. Among the canonical PWS phenotypes are hyperphagic obesity, central hypogonadism, and low growth hormone (GH). Rare microdeletions in PWS patients define a 91-kb minimum critical deletion region encompassing 3 genes, including the noncoding RNA gene SNORD116. Here, we found that protein and transcript levels of nescient helix loop helix 2 (NHLH2) and the prohormone convertase PC1 (encoded by PCSK1) were reduced in PWS patient induced pluripotent stem cell–derived (iPSC-derived) neurons. Moreover, Nhlh2 and Pcsk1 expression were reduced in hypothalami of fasted Snord116 paternal knockout (Snord116p–/m+) mice. Hypothalamic Agrp and Npy remained elevated following refeeding in association with relative hyperphagia in Snord116p–/m+ mice. Nhlh2-deficient mice display growth deficiencies as adolescents and hypogonadism, hyperphagia, and obesity as adults. Nhlh2 has also been shown to promote Pcsk1 expression. Humans and mice deficient in PC1 display hyperphagic obesity, hypogonadism, decreased GH, and hypoinsulinemic diabetes due to impaired prohormone processing. Here, we found that Snord116p–/m+ mice displayed in vivo functional defects in prohormone processing of proinsulin, pro-GH–releasing hormone, and proghrelin in association with reductions in islet, hypothalamic, and stomach PC1 content. Our findings suggest that the major neuroendocrine features of PWS are due to PC1 deficiency.

Authors

Lisa C. Burnett, Charles A. LeDuc, Carlos R. Sulsona, Daniel Paull, Richard Rausch, Sanaa Eddiry, Jayne F. Martin Carli, Michael V. Morabito, Alicja A. Skowronski, Gabriela Hubner, Matthew Zimmer, Liheng Wang, Robert Day, Brynn Levy, Ilene Fennoy, Beatrice Dubern, Christine Poitou, Karine Clement, Merlin G. Butler, Michael Rosenbaum, Jean Pierre Salles, Maithe Tauber, Daniel J. Driscoll, Dieter Egli, Rudolph L. Leibel

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Biallelic mutations in IRF8 impair human NK cell maturation and function
Emily M. Mace, … , James R. Lupski, Jordan S. Orange
Emily M. Mace, … , James R. Lupski, Jordan S. Orange
Published November 28, 2016
Citation Information: J Clin Invest. 2017;127(1):306-320. https://doi.org/10.1172/JCI86276.
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Biallelic mutations in IRF8 impair human NK cell maturation and function

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Abstract

Human NK cell deficiencies are rare yet result in severe and often fatal disease, particularly as a result of viral susceptibility. NK cells develop from hematopoietic stem cells, and few monogenic errors that specifically interrupt NK cell development have been reported. Here we have described biallelic mutations in IRF8, which encodes an interferon regulatory factor, as a cause of familial NK cell deficiency that results in fatal and severe viral disease. Compound heterozygous or homozygous mutations in IRF8 in 3 unrelated families resulted in a paucity of mature CD56dim NK cells and an increase in the frequency of the immature CD56bright NK cells, and this impairment in terminal maturation was also observed in Irf8–/–, but not Irf8+/–, mice. We then determined that impaired maturation was NK cell intrinsic, and gene expression analysis of human NK cell developmental subsets showed that multiple genes were dysregulated by IRF8 mutation. The phenotype was accompanied by deficient NK cell function and was stable over time. Together, these data indicate that human NK cells require IRF8 for development and functional maturation and that dysregulation of this function results in severe human disease, thereby emphasizing a critical role for NK cells in human antiviral defense.

Authors

Emily M. Mace, Venetia Bigley, Justin T. Gunesch, Ivan K. Chinn, Laura S. Angelo, Matthew A. Care, Sheetal Maisuria, Michael D. Keller, Sumihito Togi, Levi B. Watkin, David F. LaRosa, Shalini N. Jhangiani, Donna M. Muzny, Asbjørg Stray-Pedersen, Zeynep Coban Akdemir, Jansen B. Smith, Mayra Hernández-Sanabria, Duy T. Le, Graham D. Hogg, Tram N. Cao, Aharon G. Freud, Eva P. Szymanski, Sinisa Savic, Matthew Collin, Andrew J. Cant, Richard A. Gibbs, Steven M. Holland, Michael A. Caligiuri, Keiko Ozato, Silke Paust, Gina M. Doody, James R. Lupski, Jordan S. Orange

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Pericyte MyD88 and IRAK4 control inflammatory and fibrotic responses to tissue injury
Irina A. Leaf, … , William A. Altemeier, Jeremy S. Duffield
Irina A. Leaf, … , William A. Altemeier, Jeremy S. Duffield
Published November 21, 2016
Citation Information: J Clin Invest. 2017;127(1):321-334. https://doi.org/10.1172/JCI87532.
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Pericyte MyD88 and IRAK4 control inflammatory and fibrotic responses to tissue injury

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Abstract

Fibrotic disease is associated with matrix deposition that results in the loss of organ function. Pericytes, the precursors of myofibroblasts, are a source of pathological matrix collagens and may be promising targets for treating fibrogenesis. Here, we have shown that pericytes activate a TLR2/4- and MyD88-dependent proinflammatory program in response to tissue injury. Similarly to classic immune cells, pericytes activate the NLRP3 inflammasome, leading to IL-1β and IL-18 secretion. Released IL-1β signals through pericyte MyD88 to amplify this response. Unexpectedly, we found that MyD88 and its downstream effector kinase IRAK4 intrinsically control pericyte migration and conversion to myofibroblasts. Specific ablation of MyD88 in pericytes or pharmacological inhibition of MyD88 signaling by an IRAK4 inhibitor in vivo protected against kidney injury by profoundly attenuating tissue injury, activation, and differentiation of myofibroblasts. Our data show that in pericytes, MyD88 and IRAK4 are key regulators of 2 major injury responses: inflammatory and fibrogenic. Moreover, these findings suggest that disruption of this MyD88-dependent pathway in pericytes might be a potential therapeutic approach to inhibit fibrogenesis and promote regeneration.

Authors

Irina A. Leaf, Shunsaku Nakagawa, Bryce G. Johnson, Jin Joo Cha, Kristen Mittelsteadt, Kevin M. Guckian, Ivan G. Gomez, William A. Altemeier, Jeremy S. Duffield

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The H3K9 dimethyltransferases EHMT1/2 protect against pathological cardiac hypertrophy
Bernard Thienpont, … , Wolf Reik, Hywel Llewelyn Roderick
Bernard Thienpont, … , Wolf Reik, Hywel Llewelyn Roderick
Published November 28, 2016
Citation Information: J Clin Invest. 2017;127(1):335-348. https://doi.org/10.1172/JCI88353.
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The H3K9 dimethyltransferases EHMT1/2 protect against pathological cardiac hypertrophy

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Abstract

Cardiac hypertrophic growth in response to pathological cues is associated with reexpression of fetal genes and decreased cardiac function and is often a precursor to heart failure. In contrast, physiologically induced hypertrophy is adaptive, resulting in improved cardiac function. The processes that selectively induce these hypertrophic states are poorly understood. Here, we have profiled 2 repressive epigenetic marks, H3K9me2 and H3K27me3, which are involved in stable cellular differentiation, specifically in cardiomyocytes from physiologically and pathologically hypertrophied rat hearts, and correlated these marks with their associated transcriptomes. This analysis revealed the pervasive loss of euchromatic H3K9me2 as a conserved feature of pathological hypertrophy that was associated with reexpression of fetal genes. In hypertrophy, H3K9me2 was reduced following a miR-217–mediated decrease in expression of the H3K9 dimethyltransferases EHMT1 and EHMT2 (EHMT1/2). miR-217–mediated, genetic, or pharmacological inactivation of EHMT1/2 was sufficient to promote pathological hypertrophy and fetal gene reexpression, while suppression of this pathway protected against pathological hypertrophy both in vitro and in mice. Thus, we have established a conserved mechanism involving a departure of the cardiomyocyte epigenome from its adult cellular identity to a reprogrammed state that is accompanied by reexpression of fetal genes and pathological hypertrophy. These results suggest that targeting miR-217 and EHMT1/2 to prevent H3K9 methylation loss is a viable therapeutic approach for the treatment of heart disease.

Authors

Bernard Thienpont, Jan Magnus Aronsen, Emma Louise Robinson, Hanneke Okkenhaug, Elena Loche, Arianna Ferrini, Patrick Brien, Kanar Alkass, Antonio Tomasso, Asmita Agrawal, Olaf Bergmann, Ivar Sjaastad, Wolf Reik, Hywel Llewelyn Roderick

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Tuberous sclerosis complex inactivation disrupts melanogenesis via mTORC1 activation
Juxiang Cao, … , Hans R. Widlund, David J. Kwiatkowski
Juxiang Cao, … , Hans R. Widlund, David J. Kwiatkowski
Published December 5, 2016
Citation Information: J Clin Invest. 2017;127(1):349-364. https://doi.org/10.1172/JCI84262.
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Tuberous sclerosis complex inactivation disrupts melanogenesis via mTORC1 activation

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Abstract

Tuberous sclerosis complex (TSC) is an autosomal dominant tumor-suppressor gene syndrome caused by inactivating mutations in either TSC1 or TSC2, and the TSC protein complex is an essential regulator of mTOR complex 1 (mTORC1). Patients with TSC develop hypomelanotic macules (white spots), but the molecular mechanisms underlying their formation are not fully characterized. Using human primary melanocytes and a highly pigmented melanoma cell line, we demonstrate that reduced expression of either TSC1 or TSC2 causes reduced pigmentation through mTORC1 activation, which results in hyperactivation of glycogen synthase kinase 3β (GSK3β), followed by phosphorylation of and loss of β-catenin from the nucleus, thereby reducing expression of microphthalmia-associated transcription factor (MITF), and subsequent reductions in tyrosinase and other genes required for melanogenesis. Genetic suppression or pharmacological inhibition of this signaling cascade at multiple levels restored pigmentation. Importantly, primary melanocytes isolated from hypomelanotic macules from 6 patients with TSC all exhibited reduced TSC2 protein expression, and 1 culture showed biallelic mutation in TSC2, one of which was germline and the second acquired in the melanocytes of the hypomelanotic macule. These findings indicate that the TSC/mTORC1/AKT/GSK3β/β-catenin/MITF axis plays a central role in regulating melanogenesis. Interventions that enhance or diminish mTORC1 activity or other nodes in this pathway in melanocytes could potentially modulate pigment production.

Authors

Juxiang Cao, Magdalena E. Tyburczy, Joel Moss, Thomas N. Darling, Hans R. Widlund, David J. Kwiatkowski

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Targeting integrin α5β1 ameliorates severe airway hyperresponsiveness in experimental asthma
Aparna Sundaram, … , Xiaozhu Huang, Dean Sheppard
Aparna Sundaram, … , Xiaozhu Huang, Dean Sheppard
Published December 5, 2016
Citation Information: J Clin Invest. 2017;127(1):365-374. https://doi.org/10.1172/JCI88555.
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Targeting integrin α5β1 ameliorates severe airway hyperresponsiveness in experimental asthma

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Abstract

Treatment options are limited for severe asthma, and the need for additional therapies remains great. Previously, we demonstrated that integrin αvβ6-deficient mice are protected from airway hyperresponsiveness, due in part to increased expression of the murine ortholog of human chymase. Here, we determined that chymase protects against cytokine-enhanced bronchoconstriction by cleaving fibronectin to impair tension transmission in airway smooth muscle (ASM). Additionally, we identified a pathway that can be therapeutically targeted to mitigate the effects of airway hyperresponsiveness. Administration of chymase to human bronchial rings abrogated IL-13–enhanced contraction, and this effect was not due to alterations in calcium homeostasis or myosin light chain phosphorylation. Rather, chymase cleaved fibronectin, inhibited ASM adhesion, and attenuated focal adhesion phosphorylation. Disruption of integrin ligation with an RGD-containing peptide abrogated IL-13–enhanced contraction, with no further effect from chymase. We identified α5β1 as the primary fibronectin-binding integrin in ASM, and α5β1-specific blockade inhibited focal adhesion phosphorylation and IL-13–enhanced contraction, with no additional effect from chymase. Delivery of an α5β1 inhibitor into murine airways abrogated the exaggerated bronchoconstriction induced by allergen sensitization and challenge. Finally, α5β1 blockade enhanced the effect of the bronchodilator isoproterenol on airway relaxation. Our data identify the α5β1 integrin as a potential therapeutic target to mitigate the severity of airway contraction in asthma.

Authors

Aparna Sundaram, Chun Chen, Amin Khalifeh-Soltani, Amha Atakilit, Xin Ren, Wenli Qiu, Hyunil Jo, William DeGrado, Xiaozhu Huang, Dean Sheppard

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Prolonged red cell storage before transfusion increases extravascular hemolysis
Francesca Rapido, … , Steven L. Spitalnik, Eldad A. Hod
Francesca Rapido, … , Steven L. Spitalnik, Eldad A. Hod
Published December 12, 2016
Citation Information: J Clin Invest. 2017;127(1):375-382. https://doi.org/10.1172/JCI90837.
View: Text | PDF Clinical Research and Public Health

Prolonged red cell storage before transfusion increases extravascular hemolysis

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Abstract

BACKGROUND. Some countries have limited the maximum allowable storage duration for red cells to 5 weeks before transfusion. In the US, red blood cells can be stored for up to 6 weeks, but randomized trials have not assessed the effects of this final week of storage on clinical outcomes.

METHODS. Sixty healthy adult volunteers were randomized to a single standard, autologous, leukoreduced, packed red cell transfusion after 1, 2, 3, 4, 5, or 6 weeks of storage (n = 10 per group). 51-Chromium posttransfusion red cell recovery studies were performed and laboratory parameters measured before and at defined times after transfusion.

RESULTS. Extravascular hemolysis after transfusion progressively increased with increasing storage time (P < 0.001 for linear trend in the AUC of serum indirect bilirubin and iron levels). Longer storage duration was associated with decreasing posttransfusion red cell recovery (P = 0.002), decreasing elevations in hematocrit (P = 0.02), and increasing serum ferritin (P < 0.0001). After 6 weeks of refrigerated storage, transfusion was followed by increases in AUC for serum iron (P < 0.01), transferrin saturation (P < 0.001), and nontransferrin-bound iron (P < 0.001) as compared with transfusion after 1 to 5 weeks of storage.

CONCLUSIONS. After 6 weeks of refrigerated storage, transfusion of autologous red cells to healthy human volunteers increased extravascular hemolysis, saturated serum transferrin, and produced circulating nontransferrin-bound iron. These outcomes, associated with increased risks of harm, provide evidence that the maximal allowable red cell storage duration should be reduced to the minimum sustainable by the blood supply, with 35 days as an attainable goal.

REGISTRATION. ClinicalTrials.gov NCT02087514.

FUNDING. NIH grant HL115557 and UL1 TR000040.

Authors

Francesca Rapido, Gary M. Brittenham, Sheila Bandyopadhyay, Francesca La Carpia, Camilla L’Acqua, Donald J. McMahon, Abdelhadi Rebbaa, Boguslaw S. Wojczyk, Jane Netterwald, Hangli Wang, Joseph Schwartz, Andrew Eisenberger, Mark Soffing, Randy Yeh, Chaitanya Divgi, Yelena Z. Ginzburg, Beth H. Shaz, Sujit Sheth, Richard O. Francis, Steven L. Spitalnik, Eldad A. Hod

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Cardiac myofibroblast engulfment of dead cells facilitates recovery after myocardial infarction
Michio Nakaya, … , Shigekazu Nagata, Hitoshi Kurose
Michio Nakaya, … , Shigekazu Nagata, Hitoshi Kurose
Published December 5, 2016
Citation Information: J Clin Invest. 2017;127(1):383-401. https://doi.org/10.1172/JCI83822.
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Cardiac myofibroblast engulfment of dead cells facilitates recovery after myocardial infarction

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Abstract

Myocardial infarction (MI) results in the generation of dead cells in the infarcted area. These cells are swiftly removed by phagocytes to minimize inflammation and limit expansion of the damaged area. However, the types of cells and molecules responsible for the engulfment of dead cells in the infarcted area remain largely unknown. In this study, we demonstrated that cardiac myofibroblasts, which execute tissue fibrosis by producing extracellular matrix proteins, efficiently engulf dead cells. Furthermore, we identified a population of cardiac myofibroblasts that appears in the heart after MI in humans and mice. We found that these cardiac myofibroblasts secrete milk fat globule-epidermal growth factor 8 (MFG-E8), which promotes apoptotic engulfment, and determined that serum response factor is important for MFG-E8 production in myofibroblasts. Following MFG-E8–mediated engulfment of apoptotic cells, myofibroblasts acquired antiinflammatory properties. MFG-E8 deficiency in mice led to the accumulation of unengulfed dead cells after MI, resulting in exacerbated inflammatory responses and a substantial decrease in survival. Moreover, MFG-E8 administration into infarcted hearts restored cardiac function and morphology. MFG-E8–producing myofibroblasts mainly originated from resident cardiac fibroblasts and cells that underwent endothelial-mesenchymal transition in the heart. Together, our results reveal previously unrecognized roles of myofibroblasts in regulating apoptotic engulfment and a fundamental importance of these cells in recovery from MI.

Authors

Michio Nakaya, Kenji Watari, Mitsuru Tajima, Takeo Nakaya, Shoichi Matsuda, Hiroki Ohara, Hiroaki Nishihara, Hiroshi Yamaguchi, Akiko Hashimoto, Mitsuho Nishida, Akiomi Nagasaka, Yuma Horii, Hiroki Ono, Gentaro Iribe, Ryuji Inoue, Makoto Tsuda, Kazuhide Inoue, Akira Tanaka, Masahiko Kuroda, Shigekazu Nagata, Hitoshi Kurose

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Corrigendum
Angiopoietin-like protein 1 suppresses SLUG to inhibit cancer cell motility
Tsang-Chih Kuo, … , Jen-Liang Su, Min-Liang Kuo
Tsang-Chih Kuo, … , Jen-Liang Su, Min-Liang Kuo
Published January 3, 2017
Citation Information: J Clin Invest. 2017;127(1):402-402. https://doi.org/10.1172/JCI91882.
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Angiopoietin-like protein 1 suppresses SLUG to inhibit cancer cell motility

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Abstract

Authors

Tsang-Chih Kuo, Ching-Ting Tan, Yi-Wen Chang, Chih-Chen Hong, Wei-Jiunn Lee, Min-Wei Chen, Yung-Ming Jeng, Jean Chiou, Pei Yu, Pai-Sheng Chen, Ming-Yang Wang, Michael Hsiao, Jen-Liang Su, Min-Liang Kuo

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