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Abstract
Systemic sclerosis (SSc) is an autoimmune fibrotic disease whose pathogenesis is poorly understood and lacks effective therapies. We undertook quantitative analyses of T cell infiltrates in the skin of 35 untreated patients with early diffuse SSc and here show that CD4+ cytotoxic T cells and CD8+ T cells contribute prominently to these infiltrates. We also observed an accumulation of apoptotic cells in SSc tissues, suggesting that recurring cell death may contribute to tissue damage and remodeling in this fibrotic disease. HLA-DR–expressing endothelial cells were frequent targets of apoptosis in SSc, consistent with the prominent vasculopathy seen in patients with this disease. A circulating effector population of cytotoxic CD4+ T cells, which exhibited signatures of enhanced metabolic activity, was clonally expanded in patients with systemic sclerosis. These data suggest that cytotoxic T cells may induce the apoptotic death of endothelial and other cells in systemic sclerosis. Cell loss driven by immune cells may be followed by overly exuberant tissue repair processes that lead to fibrosis and tissue dysfunction.
Authors
Takashi Maehara, Naoki Kaneko, Cory A. Perugino, Hamid Mattoo, Jesper Kers, Hugues Allard-Chamard, Vinay S. Mahajan, Hang Liu, Samuel J.H. Murphy, Musie Ghebremichael, David Fox, Aimee S. Payne, Robert Lafyatis, John H. Stone, Dinesh Khanna, Shiv Pillai
Abstract
Lamin A is a component of the inner nuclear membrane that, together with epigenetic factors, organizes the genome in higher order structures required for transcriptional control. Mutations in the lamin A/C gene cause several diseases belonging to the class of laminopathies, including muscular dystrophies. Nevertheless, molecular mechanisms involved in the pathogenesis of lamin A–dependent dystrophies are still largely unknown. The polycomb group (PcG) of proteins are epigenetic repressors and lamin A interactors, primarily involved in the maintenance of cell identity. Using a murine model of Emery-Dreifuss muscular dystrophy (EDMD), we show here that lamin A loss deregulated PcG positioning in muscle satellite stem cells, leading to derepression of non–muscle-specific genes and p16INK4a, a senescence driver encoded in the Cdkn2a locus. This aberrant transcriptional program caused impairment in self-renewal, loss of cell identity, and premature exhaustion of the quiescent satellite cell pool. Genetic ablation of the Cdkn2a locus restored muscle stem cell properties in lamin A/C–null dystrophic mice. Our findings establish a direct link between lamin A and PcG epigenetic silencing and indicate that lamin A–dependent muscular dystrophy can be ascribed to intrinsic epigenetic dysfunctions of muscle stem cells.
Authors
Andrea Bianchi, Chiara Mozzetta, Gloria Pegoli, Federica Lucini, Sara Valsoni, Valentina Rosti, Cristiano Petrini, Alice Cortesi, Francesco Gregoretti, Laura Antonelli, Gennaro Oliva, Marco De Bardi, Roberto Rizzi, Beatrice Bodega, Diego Pasini, Francesco Ferrari, Claudia Bearzi, Chiara Lanzuolo
Abstract
BACKGROUND Preclinical experiments have shown that donor blood cells, modified in vitro by an alkylating agent (modified immune cells [MICs]), induced long-term specific immunosuppression against the allogeneic donor.METHODS In this phase I trial, patients received either 1.5 × 106 MICs per kg BW on day –2 (n = 3, group A), or 1.5 × 108 MICs per kg BW on day –2 (n = 3, group B) or day –7 (n = 4, group C) before living donor kidney transplantation in addition to post-transplantation immunosuppression. The primary outcome measure was the frequency of adverse events (AEs) until day 30 (study phase) with follow-up out to day 360.RESULTS MIC infusions were extremely well tolerated. During the study phase, 10 treated patients experienced a total of 69 AEs that were unlikely to be related or not related to MIC infusion. No donor-specific human leukocyte antigen Abs or rejection episodes were noted, even though the patients received up to 1.3 × 1010 donor mononuclear cells before transplantation. Group C patients with low immunosuppression during follow-up showed no in vitro reactivity against stimulatory donor blood cells on day 360, whereas reactivity against third-party cells was still preserved. Frequencies of CD19+CD24hiCD38hi transitional B lymphocytes (Bregs) increased from a median of 6% before MIC infusion to 20% on day 180, which was 19- and 68-fold higher, respectively, than in 2 independent cohorts of transplanted controls. The majority of Bregs produced the immunosuppressive cytokine IL-10. MIC-treated patients showed the Immune Tolerance Network operational tolerance signature.CONCLUSION MIC administration was safe and could be a future tool for the targeted induction of tolerogenic Bregs.TRIAL REGISTRATION EudraCT number: 2014-002086-30; ClinicalTrials.gov identifier: NCT02560220FUNDING Federal Ministry for Economic Affairs and Technology, Berlin, Germany, and TolerogenixX GmbH, Heidelberg, Germany.
Authors
Christian Morath, Anita Schmitt, Christian Kleist, Volker Daniel, Gerhard Opelz, Caner Süsal, Eman Ibrahim, Florian Kälble, Claudius Speer, Christian Nusshag, Luiza Pego da Silva, Claudia Sommerer, Lei Wang, Ming Ni, Angela Hückelhoven-Krauss, David Czock, Uta Merle, Arianeb Mehrabi, Anja Sander, Matthes Hackbusch, Christoph Eckert, Rüdiger Waldherr, Paul Schnitzler, Carsten Müller-Tidow, Jörg D. Hoheisel, Shakhawan A. Mustafa, Mohamed S.S. Alhamdani, Andrea S. Bauer, Jochen Reiser, Martin Zeier, Michael Schmitt, Matthias Schaier, Peter Terness
Abstract
Fibroblasts are key effector cells in tissue remodeling. They remain persistently activated in fibrotic diseases, resulting in progressive deposition of extracellular matrix. Although fibroblast activation may be initiated by external factors, prolonged activation can induce an “autonomous,” self-maintaining profibrotic phenotype in fibroblasts. Accumulating evidence suggests that epigenetic alterations play a central role in establishing this persistently activated pathologic phenotype of fibroblasts. We demonstrated that in fibrotic skin of patients with systemic sclerosis (SSc), a prototypical idiopathic fibrotic disease, TGF-β induced the expression of DNA methyltransferase 3A (DNMT3A) and DNMT1 in fibroblasts in a SMAD-dependent manner to silence the expression of suppressor of cytokine signaling 3 (SOCS3) by promoter hypermethylation. Downregulation of SOCS3 facilitated activation of STAT3 to promote fibroblast-to-myofibroblast transition, collagen release, and fibrosis in vitro and in vivo. Reestablishment of the epigenetic control of STAT3 signaling by genetic or pharmacological inactivation of DNMT3A reversed the activated phenotype of SSc fibroblasts in tissue culture, inhibited TGF-β–dependent fibroblast activation, and ameliorated experimental fibrosis in murine models. These findings identify a pathway of epigenetic imprinting of fibroblasts in fibrotic disease with translational implications for the development of targeted therapies in fibrotic diseases.
Authors
Clara Dees, Sebastian Pötter, Yun Zhang, Christina Bergmann, Xiang Zhou, Markus Luber, Thomas Wohlfahrt, Emmanuel Karouzakis, Andreas Ramming, Kolja Gelse, Akihiko Yoshimura, Rudolf Jaenisch, Oliver Distler, Georg Schett, Jörg H.W. Distler
Abstract
Colitis caused by Clostridium difficile infection is a growing cause of human morbidity and mortality, especially after antibiotic use in health care settings. The natural immunity of newborn infants and protective host immune mediators against C. difficile infection are not fully understood, with data suggesting that inflammation can be either protective or pathogenic. Here, we show an essential role for IL-17A produced by γδ T cells in host defense against C. difficile infection. Fecal extracts from children with C. difficile infection showed increased IL-17A and T cell receptor γ chain expression, and IL-17 production by intestinal γδ T cells was efficiently induced after infection in mice. C. difficile–induced tissue inflammation and mortality were markedly increased in mice deficient in IL-17A or γδ T cells. Neonatal mice, with naturally expanded RORγt+ γδ T cells poised for IL-17 production were resistant to C. difficile infection, whereas elimination of γδ T cells or IL-17A each efficiently overturned neonatal resistance against infection. These results reveal an expanded role for IL-17–producing γδ T cells in neonatal host defense against infection and provide a mechanistic explanation for the clinically observed resistance of infants to C. difficile colitis.
Authors
Yee-Shiuan Chen, Iuan-Bor Chen, Giang Pham, Tzu-Yu Shao, Hansraj Bangar, Sing Sing Way, David B. Haslam
Abstract
Immunosuppression continues to be a necessary component of transplantation, despite its association with a multitude of adverse effects. Numerous efforts have been made to circumvent the need for immunosuppression by using various techniques to achieve donor hyporesponsiveness. In this issue of the JCI, Morath et al. take this endeavor forward. Prior to transplantation, the researchers infused recipients with donor-modified immune cells and achieved immunologic hyporesponsiveness. This successful phase I trial also provides a possible avenue for achieving transplantation without the requisite immunosuppression.
Authors
Sam Kant, Daniel C. Brennan
Abstract
Seizures often herald the clinical appearance of gliomas or appear at later stages. Dissecting their precise evolution and cellular pathogenesis in brain malignancies could inform the development of staged therapies for these highly pharmaco-resistant epilepsies. Studies in immunodeficient xenograft models have identified local interneuron loss and excess glial glutamate release as chief contributors to network disinhibition, but how hyperexcitability in the peritumoral microenvironment evolves in an immunocompetent brain is unclear. We generated gliomas in WT mice via in utero deletion of key tumor suppressor genes and serially monitored cortical epileptogenesis during tumor infiltration with in vivo electrophysiology and GCAMP7 calcium imaging, revealing a reproducible progression from hyperexcitability to convulsive seizures. Long before seizures, coincident with loss of inhibitory cells and their protective scaffolding, gain of glial glutamate antiporter xCT expression, and reactive astrocytosis, we detected local Iba1+ microglial inflammation that intensified and later extended far beyond tumor boundaries. Hitherto unrecognized episodes of cortical spreading depolarization that arose frequently from the peritumoral region may provide a mechanism for transient neurological deficits. Early blockade of glial xCT activity inhibited later seizures, and genomic reduction of host brain excitability by deleting MapT suppressed molecular markers of epileptogenesis and seizures. Our studies confirmed xenograft tumor–driven pathobiology and revealed early and late components of tumor-related epileptogenesis in a genetically tractable, immunocompetent mouse model of glioma, allowing the complex dissection of tumor versus host pathogenic seizure mechanisms.
Authors
Asante Hatcher, Kwanha Yu, Jochen Meyer, Isamu Aiba, Benjamin Deneen, Jeffrey L. Noebels
Abstract
Approximately half of the world’s population is infected with the stomach pathogen Helicobacter pylori. Infection with H. pylori is the main risk factor for distal gastric cancer. Bacterial virulence factors, such as the oncoprotein CagA, augment cancer risk. Yet despite high infection rates, only a fraction of H. pylori–infected individuals develop gastric cancer. This raises the question of defining the specific host and bacterial factors responsible for gastric tumorigenesis. To investigate the tumorigenic determinants, we analyzed gastric tissues from human subjects and animals infected with H. pylori bacteria harboring different CagA status. For laboratory studies, well-defined H. pylori strain B128 and its cancerogenic derivative strain 7.13, as well as various bacterial isogenic mutants were employed. We found that H. pylori compromises key tumor suppressor mechanisms: the host stress and apoptotic responses. Our studies showed that CagA induces phosphorylation of XIAP E3 ubiquitin ligase, which enhances ubiquitination and proteasomal degradation of the host proapoptotic factor Siva1. This process is mediated by the PI3K/Akt pathway. Inhibition of Siva1 by H. pylori increases survival of human cells with damaged DNA. It occurs in a strain-specific manner and is associated with the ability to induce gastric tumor.
Authors
Manikandan Palrasu, Elena Zaika, Wael El-Rifai, Monica Garcia-Buitrago, Maria Blanca Piazuelo, Keith T. Wilson, Richard M. Peek Jr., Alexander I. Zaika
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is caused by loss of repression of the DUX4 gene; however, the DUX4 protein is rare and difficult to detect in human muscle biopsies, and pathological mechanisms are obscure. FSHD is also a chronic disease that progresses slowly over decades. We used the sporadic, low-level, muscle-specific expression of DUX4 enabled by the iDUX4pA-HSA mouse to develop a chronic long-term muscle disease model. After 6 months of extremely low sporadic DUX4 expression, dystrophic muscle presented hallmarks of FSHD histopathology, including muscle degeneration, capillary loss, fibrosis, and atrophy. We investigated the transcriptional profile of whole muscle as well as endothelial cells and fibroadiopogenic progenitors (FAPs). Strikingly, differential gene expression profiles of both whole muscle and, to a lesser extent, FAPs, showed significant overlap with transcriptional profiles of MRI-guided human FSHD muscle biopsies. These results demonstrate a pathophysiological similarity between disease in muscles of iDUX4pA-HSA mice and humans with FSHD, solidifying the value of chronic rare DUX4 expression in mice for modeling pathological mechanisms in FSHD and highlighting the importance FAPs in this disease.
Authors
Darko Bosnakovski, Ahmed S. Shams, Ce Yuan, Meiricris T. da Silva, Elizabeth T. Ener, Cory W. Baumann, Angus J. Lindsay, Mayank Verma, Atsushi Asakura, Dawn A. Lowe, Michael Kyba
Abstract
The mechanisms by which prostate cancer shifts from an indolent castration-sensitive phenotype to lethal castration-resistant prostate cancer (CRPC) are poorly understood. Identification of clinically relevant genetic alterations leading to CRPC may reveal potential vulnerabilities for cancer therapy. Here we find that CUB domain-containing protein 1 (CDCP1), a transmembrane protein that acts as a substrate for SRC family kinases (SFKs), is overexpressed in a subset of CRPC. Notably, CDCP1 cooperates with the loss of the tumor suppressor gene PTEN to promote the emergence of metastatic prostate cancer. Mechanistically, we find that androgens suppress CDCP1 expression and that androgen deprivation in combination with loss of PTEN promotes the upregulation of CDCP1 and the subsequent activation of the SRC/MAPK pathway. Moreover, we demonstrate that anti-CDCP1 immunoliposomes (anti–CDCP1 ILs) loaded with chemotherapy suppress prostate cancer growth when administered in combination with enzalutamide. Thus, our study identifies CDCP1 as a powerful driver of prostate cancer progression and uncovers different potential therapeutic strategies for the treatment of metastatic prostate tumors.
Authors
Abdullah Alajati, Mariantonietta D’Ambrosio, Martina Troiani, Simone Mosole, Laura Pellegrini, Jingjing Chen, Ajinkya Revandkar, Marco Bolis, Jean-Philippe Theurillat, Ilaria Guccini, Marco Losa, Arianna Calcinotto, Gaston De Bernardis, Emiliano Pasquini, Rocco D’Antuono, Adam Sharp, Ines Figueiredo, Daniel Nava Rodrigues, Jonathan Welti, Veronica Gil, Wei Yuan, Tatjana Vlajnic, Lukas Bubendorf, Giovanna Chiorino, Letizia Gnetti, Verónica Torrano, Arkaitz Carracedo, Laura Camplese, Susumu Hirabayashi, Elena Canato, Gianfranco Pasut, Monica Montopoli, Jan Hendrik Rüschoff, Peter Wild, Holger Moch, Johann De Bono, Andrea Alimonti
Abstract
Infection with the Gram-negative bacterium Helicobacter pylori remains the most important modifiable risk factor for the development of gastric cancer, a leading cause of cancer-related deaths worldwide. How the interactions between H. pylori and its host shape the gastric environment during chronic infection warrants further investigation. In this issue of the JCI, Palrasu et al. used human cell lines and mouse models to provide mechanistic insight into H. pylori’s ability to delay apoptosis in gastric epithelial cells by actively driving the degradation of a proapoptotic factor, SIVA1. Their findings suggest that promoting the survival of gastric epithelial cells has implications not only for H. pylori pathogenesis but for host tumorigenesis.
Authors
José B. Sáenz, Jason C. Mills
Abstract
The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing worldwide. Although gene-environment interactions have been implicated in the etiology of several disorders, the impact of paternal and/or maternal metabolic syndrome on the clinical phenotypes of offspring and the underlying genetic and epigenetic contributors of NAFLD have not been fully explored. To this end, we used the liver-specific insulin receptor knockout (LIRKO) mouse, a unique nondietary model manifesting 3 hallmarks that confer high risk for the development of NAFLD: hyperglycemia, insulin resistance, and dyslipidemia. We report that parental metabolic syndrome epigenetically reprograms members of the TGF-β family, including neuronal regeneration–related protein (NREP) and growth differentiation factor 15 (GDF15). NREP and GDF15 modulate the expression of several genes involved in the regulation of hepatic lipid metabolism. In particular, NREP downregulation increases the protein abundance of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and ATP-citrate lyase (ACLY) in a TGF-β receptor/PI3K/protein kinase B–dependent manner, to regulate hepatic acetyl-CoA and cholesterol synthesis. Reduced hepatic expression of NREP in patients with NAFLD and substantial correlations between low serum NREP levels and the presence of steatosis and nonalcoholic steatohepatitis highlight the clinical translational relevance of our findings in the context of recent preclinical trials implicating ACLY in NAFLD progression.
Authors
Dario F. De Jesus, Kazuki Orime, Dorota Kaminska, Tomohiko Kimura, Giorgio Basile, Chih-Hao Wang, Larissa Haertle, Renzo Riemens, Natalie K. Brown, Jiang Hu, Ville Männistö, Amélia M. Silva, Ercument Dirice, Yu-Hua Tseng, Thomas Haaf, Jussi Pihlajamäki, Rohit N. Kulkarni
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) results from expression of the full-length double homeobox 4 (DUX4-FL) retrogene in skeletal muscle. However, even in cases of severe FSHD the presence of DUX4 is barely detectable. In this issue of the JCI, Bosnakovski et al. used an inducible, muscle-specific human DUX4 to reproduce the low-level, sporadic DUX4 expression of human FSHD muscle as well the myopathology seen in human FSHD disease. Notably, dysregulated fibroadipogenic progenitors accumulated in affected muscles, thus providing a mechanism for the replacement of muscle by fibrosis and fat.
Authors
Carlo Serra, Kathryn R. Wagner
Abstract
Regenerative pain medicine, which seeks to harness the body’s own reparative capacity, is rapidly emerging as a field within pain medicine and orthopedics. It is increasingly appreciated that common analgesic mechanisms for these treatments depend on neuroimmune modulation. In this Review, we discuss recent progress in mechanistic understanding of nociceptive sensitization in chronic pain with a focus on neuroimmune modulation. We also examine the spectrum of regenerative outcomes, including preclinical and clinical outcomes. We further distinguish the analgesic mechanisms of regenerative therapies from those of cellular replacement, creating a conceptual and mechanistic framework to evaluate future research on regenerative medicine.
Authors
Thomas Buchheit, Yul Huh, William Maixner, Jianguo Cheng, Ru-Rong Ji
Abstract
BACKGROUND Beige adipose tissue is associated with improved glucose homeostasis in mice. Adipose tissue contains β3-adrenergic receptors (β3-ARs), and this study was intended to determine whether the treatment of obese, insulin-resistant humans with the β3-AR agonist mirabegron, which stimulates beige adipose formation in subcutaneous white adipose tissue (SC WAT), would induce other beneficial changes in fat and muscle and improve metabolic homeostasis.METHODS Before and after β3-AR agonist treatment, oral glucose tolerance tests and euglycemic clamps were performed, and histochemical analysis and gene expression profiling were performed on fat and muscle biopsies. PET-CT scans quantified brown adipose tissue volume and activity, and we conducted in vitro studies with primary cultures of differentiated human adipocytes and muscle.RESULTS The clinical effects of mirabegron treatment included improved oral glucose tolerance (P < 0.01), reduced hemoglobin A1c levels (P = 0.01), and improved insulin sensitivity (P = 0.03) and β cell function (P = 0.01). In SC WAT, mirabegron treatment stimulated lipolysis, reduced fibrotic gene expression, and increased alternatively activated macrophages. Subjects with the most SC WAT beiging showed the greatest improvement in β cell function. In skeletal muscle, mirabegron reduced triglycerides, increased the expression of PPARγ coactivator 1 α (PGC1A) (P < 0.05), and increased type I fibers (P < 0.01). Conditioned media from adipocytes treated with mirabegron stimulated muscle fiber PGC1A expression in vitro (P < 0.001).CONCLUSION Mirabegron treatment substantially improved multiple measures of glucose homeostasis in obese, insulin-resistant humans. Since β cells and skeletal muscle do not express β3-ARs, these data suggest that the beiging of SC WAT by mirabegron reduces adipose tissue dysfunction, which enhances muscle oxidative capacity and improves β cell function.TRIAL REGISTRATION Clinicaltrials.gov NCT02919176.FUNDING NIH: DK112282, P30GM127211, DK 71349, and Clinical and Translational science Awards (CTSA) grant UL1TR001998.
Authors
Brian S. Finlin, Hasiyet Memetimin, Beibei Zhu, Amy L. Confides, Hemendra J. Vekaria, Riham H. El Khouli, Zachary R. Johnson, Philip M. Westgate, Jianzhong Chen, Andrew J. Morris, Patrick G. Sullivan, Esther E. Dupont-Versteegden, Philip A. Kern
Abstract
BACKGROUND The live attenuated BPZE1 vaccine candidate induces protection against B. pertussis and prevents nasal colonization in animal models. Here we report on the responses in humans receiving a single intranasal administration of BPZE1.METHODS We performed multiple assays to dissect the immune responses induced in humans (n = 12) receiving BPZE1, with particular emphasis on the magnitude and characteristics of the antibody responses. Such responses were benchmarked to adolescents (n = 12) receiving the complete vaccination program of the currently used acellular pertussis vaccine (aPV). Using immunoproteomics analysis, potentially novel immunogenic B. pertussis antigens were identified.RESULTS All BPZE1 vaccinees showed robust B. pertussis–specific antibody responses with regard to significant increase in 1 or more of the following parameters: IgG, IgA, and memory B cells to B. pertussis antigens. BPZE1–specific T cells showed a Th1 phenotype, and the IgG exclusively consisted of IgG1 and IgG3. In contrast, all aPV vaccines showed a Th2-biased response. Immunoproteomics profiling revealed that BPZE1 elicited broader and different antibody specificities to B. pertussis antigens as compared with the aPV that primarily induced antibodies to the vaccine antigens. Moreover, BPZE1 was superior at inducing opsonizing antibodies that stimulated ROS production in neutrophils and enhanced bactericidal function, which was in line with the finding that antibodies against adenylate cyclase toxin were only elicited by BPZE1.CONCLUSION The breadth of the antibodies, the Th1-type cellular response, and killing mechanisms elicited by BPZE1 may hold prospects of improving vaccine efficacy and protection against B. pertussis transmission.TRIAL REGISTRATION ClinicalTrials.gov NCT02453048, NCT00870350.FUNDING ILiAD Biotechnologies, Swedish Research Council (Vetenskapsrådet), Swedish Heart-Lung Foundation.
Authors
Ang Lin, Danijela Apostolovic, Maja Jahnmatz, Frank Liang, Sebastian Ols, Teghesti Tecleab, Chenyan Wu, Marianne van Hage, Ken Solovay, Keith Rubin, Camille Locht, Rigmor Thorstensson, Marcel Thalen, Karin Loré
Abstract
Increased microvascular permeability to plasma proteins and neutrophil emigration are hallmarks of innate immunity and key features of numerous inflammatory disorders. Although neutrophils can promote microvascular leakage, the impact of vascular permeability on neutrophil trafficking is unknown. Here, through the application of confocal intravital microscopy, we report that vascular permeability–enhancing stimuli caused a significant frequency of neutrophil reverse transendothelial cell migration (rTEM). Furthermore, mice with a selective defect in microvascular permeability enhancement (VEC-Y685F-ki) showed reduced incidence of neutrophil rTEM. Mechanistically, elevated vascular leakage promoted movement of interstitial chemokines into the bloodstream, a response that supported abluminal-to-luminal neutrophil TEM. Through development of an in vivo cell labeling method we provide direct evidence for the systemic dissemination of rTEM neutrophils, and showed them to exhibit an activated phenotype and be capable of trafficking to the lungs where their presence was aligned with regions of vascular injury. Collectively, we demonstrate that increased microvascular leakage reverses the localization of directional cues across venular walls, thus causing neutrophils engaged in diapedesis to reenter the systemic circulation. This cascade of events offers a mechanism to explain how local tissue inflammation and vascular permeability can induce downstream pathological effects in remote organs, most notably in the lungs.
Authors
Charlotte Owen-Woods, Régis Joulia, Anna Barkaway, Loïc Rolas, Bin Ma, Astrid Fee Nottebaum, Kenton P. Arkill, Monja Stein, Tamara Girbl, Matthew Golding, David O. Bates, Dietmar Vestweber, Mathieu-Benoit Voisin, Sussan Nourshargh
Abstract
BACKGROUND Mirabegron is a β3-adrenergic receptor (β3-AR) agonist approved only for the treatment of overactive bladder. Encouraging preclinical results suggest that β3-AR agonists could also improve obesity-related metabolic disease by increasing brown adipose tissue (BAT) thermogenesis, white adipose tissue (WAT) lipolysis, and insulin sensitivity.METHODS We treated 14 healthy women of diverse ethnicities (27.5 ± 1.1 years of age, BMI of 25.4 ± 1.2 kg/m2) with 100 mg mirabegron (Myrbetriq extended-release tablet, Astellas Pharma) for 4 weeks in an open-label study. The primary endpoint was the change in BAT metabolic activity as measured by [18F]-2-fluoro-d-2-deoxy-d-glucose (18F-FDG) PET/CT. Secondary endpoints included resting energy expenditure (REE), plasma metabolites, and glucose and insulin metabolism as assessed by a frequently sampled intravenous glucose tolerance test.RESULTS Chronic mirabegron therapy increased BAT metabolic activity. Whole-body REE was higher, without changes in body weight or composition. Additionally, there were elevations in plasma levels of the beneficial lipoprotein biomarkers HDL and ApoA1, as well as total bile acids. Adiponectin, a WAT-derived hormone that has antidiabetic and antiinflammatory capabilities, increased with acute treatment and was 35% higher upon completion of the study. Finally, an intravenous glucose tolerance test revealed higher insulin sensitivity, glucose effectiveness, and insulin secretion.CONCLUSION These findings indicate that human BAT metabolic activity can be increased after chronic pharmacological stimulation with mirabegron and support the investigation of β3-AR agonists as a treatment for metabolic disease.TRIAL REGISTRATION Clinicaltrials.gov NCT03049462.FUNDING This work was supported by grants from the Intramural Research Program of the NIDDK, NIH (DK075112, DK075116, DK071013, and DK071014).
Authors
Alana E. O’Mara, James W. Johnson, Joyce D. Linderman, Robert J. Brychta, Suzanne McGehee, Laura A. Fletcher, Yael A. Fink, Devika Kapuria, Thomas M. Cassimatis, Nathan Kelsey, Cheryl Cero, Zahraa Abdul Sater, Francesca Piccinini, Alison S. Baskin, Brooks P. Leitner, Hongyi Cai, Corina M. Millo, William Dieckmann, Mary Walter, Norman B. Javitt, Yaron Rotman, Peter J. Walter, Marilyn Ader, Richard N. Bergman, Peter Herscovitch, Kong Y. Chen, Aaron M. Cypess
Abstract
Hypoxia-inducible factor (HIF) is strikingly upregulated in many types of cancer, and there is great interest in applying inhibitors of HIF as anticancer therapeutics. The most advanced of these are small molecules that target the HIF-2 isoform through binding the PAS-B domain of HIF-2α. These molecules are undergoing clinical trials with promising results in renal and other cancers where HIF-2 is considered to be driving growth. Nevertheless, a central question remains as to whether such inhibitors affect physiological responses to hypoxia at relevant doses. Here, we show that pharmacological HIF-2α inhibition with PT2385, at doses similar to those reported to inhibit tumor growth, rapidly impaired ventilatory responses to hypoxia, abrogating both ventilatory acclimatization and carotid body cell proliferative responses to sustained hypoxia. Mice carrying a HIF-2α PAS-B S305M mutation that disrupts PT2385 binding, but not dimerization with HIF-1β, did not respond to PT2385, indicating that these effects are on-target. Furthermore, the finding of a hypomorphic ventilatory phenotype in untreated HIF-2α S305M mutant mice suggests a function for the HIF-2α PAS-B domain beyond heterodimerization with HIF-1β. Although PT2385 was well tolerated, the findings indicate the need for caution in patients who are dependent on hypoxic ventilatory drive.
Authors
Xiaotong Cheng, Maria Prange-Barczynska, James W. Fielding, Minghao Zhang, Alana L. Burrell, Joanna D.C.C. Lima, Luise Eckardt, Isobel L.A. Argles, Christopher W. Pugh, Keith J. Buckler, Peter A. Robbins, Emma J. Hodson, Richard K. Bruick, Lucy M. Collinson, Fraydoon Rastinejad, Tammie Bishop, Peter J. Ratcliffe
Abstract
BACKGROUND Glucose-6-phosphate dehydrogenase (G6PD) deficiency decreases the ability of red blood cells (RBCs) to withstand oxidative stress. Refrigerated storage of RBCs induces oxidative stress. We hypothesized that G6PD-deficient donor RBCs would have inferior storage quality for transfusion as compared with G6PD-normal RBCs.METHODS Male volunteers were screened for G6PD deficiency; 27 control and 10 G6PD-deficient volunteers each donated 1 RBC unit. After 42 days of refrigerated storage, autologous 51-chromium 24-hour posttransfusion RBC recovery (PTR) studies were performed. Metabolomics analyses of these RBC units were also performed.RESULTS The mean 24-hour PTR for G6PD-deficient subjects was 78.5% ± 8.4% (mean ± SD), which was significantly lower than that for G6PD-normal RBCs (85.3% ± 3.2%; P = 0.0009). None of the G6PD-normal volunteers (0/27) and 3 G6PD-deficient volunteers (3/10) had PTR results below 75%, a key FDA acceptability criterion for stored donor RBCs. As expected, fresh G6PD-deficient RBCs demonstrated defects in the oxidative phase of the pentose phosphate pathway. During refrigerated storage, G6PD-deficient RBCs demonstrated increased glycolysis, impaired glutathione homeostasis, and increased purine oxidation, as compared with G6PD-normal RBCs. In addition, there were significant correlations between PTR and specific metabolites in these pathways.CONCLUSION Based on current FDA criteria, RBCs from G6PD-deficient donors would not meet the requirements for storage quality. Metabolomics assessment identified markers of PTR and G6PD deficiency (e.g., pyruvate/lactate ratios), along with potential compensatory pathways that could be leveraged to ameliorate the metabolic needs of G6PD-deficient RBCs.TRIAL REGISTRATION ClinicalTrials.gov NCT04081272.FUNDING The Harold Amos Medical Faculty Development Program, Robert Wood Johnson Foundation grant 71590, the National Blood Foundation, NIH grant UL1 TR000040, the Webb-Waring Early Career Award 2017 by the Boettcher Foundation, and National Heart, Lung, and Blood Institute grants R01HL14644 and R01HL148151.
Authors
Richard O. Francis, Angelo D’Alessandro, Andrew Eisenberger, Mark Soffing, Randy Yeh, Esther Coronel, Arif Sheikh, Francesca Rapido, Francesca La Carpia, Julie A. Reisz, Sarah Gehrke, Travis Nemkov, Tiffany Thomas, Joseph Schwartz, Chaitanya Divgi, Debra Kessler, Beth H. Shaz, Yelena Ginzburg, James C. Zimring, Steven L. Spitalnik, Eldad A. Hod
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Abstract
The current COVID-19 pandemic has affected everyone, but presents profound consequences for patients with kidney disease, health care providers, and biomedical researchers. In this Viewpoint, I will discuss a number of kidney-specific aspects of COVID-19 infection, noting therapeutic and basic research opportunities.
Authors
Hamid Rabb
Abstract
This viewpoint addresses the major impact of the COVID-19 pandemic on biomedical research, the challenges created by the COVID-19 pandemic for research-intensive institutions, and what investigators can do to maintain some level of research activity while keeping their coworkers and trainees safe and engaged.
Authors
M. Bishr Omary, Jeetendra R. Eswaraka, S. David Kimball, Prabhas V. Moghe, Reynold A. Panettieri, Jr., Kathleen W. Scotto
Abstract
A common variant in the RAB27A gene in adults was recently found to be associated with the fractional exhaled nitric oxide level, a marker of eosinophilic airway inflammation. The small GTPase, Rab27, is known to regulate intracellular vesicle traffic, although its role in allergic responses is unclear. We demonstrated that exophilin-5, a Rab27 binding protein, was predominantly expressed in both the major IL-33 producers, lung epithelial cells, and the specialized IL-5 and IL-13 producers in CD44highCXCR3lowCD62Llow pathogenic T helper 2 (Th2) cell population in mice. Exophilin-5 deficiency increased stimulant-dependent damages and IL-33 secretion of lung epithelial cells. Moreover, it enhanced IL-5 and IL-13 production in response to TCR and IL-33 stimulation from a specific subset of pathogenic Th2 cells that expresses a high level of IL-33 receptor, which exacerbated allergic airway inflammation in a mouse model of asthma. Mechanistically, exophilin-5 regulates extracellular superoxide release, intracellular ROS production, and phosphoinositide 3-kinase activity by controlling intracellular traffic of Nox2-containing vesicles, which seems to prevent the overactivation of pathogenic Th2 cells mediated by IL-33. This is the first report to establish the significance of Rab27-related protein exophilin-5 in the development of allergic airway inflammation, and provides new insights into the pathophysiology of asthma.
Authors
Katsuhide Okunishi, Hao Wang, Maho Suzukawa, Ray Ishizaki, Eri Kobayashi, Miho Kihara, Takaya Abe, Jun-ichi Miyazaki, Masafumi Horie, Akira Saito, Hirohisa Saito, Susumu Nakae, Tetsuro Izumi
Abstract
Hidradenitis suppurativa (HS) is a chronic, relapsing, inflammatory skin disease. HS appears to be a primary abnormality in the pilosebaceous-apocrine unit. In this work, we characterized hair follicle stem cells isolated from HS patients and more precisely the Outer Root Sheath Cells (ORS). We show that hair follicles from HS patients have an increased number of proliferating progenitor cells and lose quiescent stem cells. Remarkably, we also show that the progression of replication forks is altered in HS-ORS and activates the ATR-CHK1 pathway. These alterations are associated with an increased number of micronuclei and with the presence of cytoplasmic ssDNA, leading to the activation of IFI16-STING pathway and the production of type I IFNs. This mechanistic analysis of the etiology of HS in the hair follicle stem cells compartment establishes a formal link between the genetic predisposition and skin inflammation observed in HS.
Authors
Cindy Orvain, Yea-Lih Lin, Francette Jean-Louis, Hakim Hocini, Barbara Hersant, Yamina Bennasser, Nicolas Ortonne, Claire Hotz, Pierre Wolkenstein, Michele Boniotto, Pascaline Tisserand, Cecile Lefebvre, Jean-Daniel Lelievre, Monsef Benkirane, Philippe Pasero, Yves Levy, Sophie Hue
Abstract
Germinal center (GC) responses require B cells to respond to a dynamic set of intercellular and microenvironmental signals that instruct B cell positioning, differentiation, and metabolic reprogramming. ROCK2, a serine-threonine kinase that can be therapeutically targeted by ROCK inhibitors or statins, is a key downstream effector of RHOA-GTPases. While RHOA-mediated pathways are emerging as critical regulators of GC responses, the role of ROCK2 in B cells is unknown. Here, we find that ROCK2 was activated in response to key T cell signals like CD40 and IL21 and that it regulated GC formation and maintenance. RNA-seq analyses revealed that ROCK2 controlled a unique transcriptional program in GC B cells that promoted optimal GC polarization and cholesterol biosynthesis. ROCK2 regulated this program by restraining AKT activation and subsequently enhancing FOXO1 activity. ATAC-seq and biochemical analyses revealed that the effects of ROCK2 on cholesterol biosynthesis were instead mediated via a novel mechanism. ROCK2 directly phosphorylated IRF8, a crucial mediator of GC responses, and promoted its interaction with SREBP2 at key regulatory regions controlling the expression of cholesterol biosynthetic enzymes, resulting in optimal recruitment of SREBP2 at these sites. These findings thus uncover ROCK2 as a multifaceted and therapeutically targetable regulator of GC responses.
Authors
Edd Ricker, Yurii Chinenov, Tania Pannellini, Danny M. Flores Castro, Chao Ye, Sanjay Gupta, Michela Manni, James K. Liao, Alessandra Pernis
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April 2020
On the cover:
IFN-driven neuroinflammation in Alzheimer disease
April 2020 Issue
On the cover:
IFN-driven neuroinflammation in Alzheimer disease
Pathologic inflammation leading to neurodegeneration in Alzheimer disease (AD) may be driven by immunogenic responses to β-amyloid (Aβ) fibrils, aggregates of soluble proteins that form insoluble secondary structures. In this issue of the JCI, Roy et al. highlight the IFN pathway’s contribution to neuropathology in models of AD. They reveal that Aβ-driven activation of IFN signaling in microglia drives microgliosis as well as complement-mediated synapse loss in mice. Blocking IFN reduced inflammation and synapse loss in these models. Together, the observations support further examination of the IFN pathway as a target in treating AD. The accompanying image shows the accumulation of activated microglia (Iba1, green; Clec7a, yellow) associated with Aβ plaques (blue) in a mouse model of AD. Image credit: Ethan Roy.
JCI This Month
April 2020 JCI This Month
JCI This Month is a digest of the research, reviews, and other features published each month.
Review Series - More
Series edited by Leo Luznik
Immunotherapy in Hematological Cancers
Series edited by Leo Luznik
Immunotherapeutic strategies leveraging the immune system’s antitumor activity have become a mainstay of cancer treatment. Strategies including antibody-directed approaches, stem cell transplantation, immunomodulatory drugs, immune checkpoint inhibitors, CAR T cells, and vaccines have demonstrated particular success in controlling and even eradicating hematological cancers. This Review Series, developed by JCI’s associate editor Leo Luznik, discusses ongoing progress in immunotherapeutic targeting of hematological cancers. Reviews will address the state-of-the-art in immunotherapies for acute myeloid leukemia, multiple myeloma, and lymphoma and highlight recent successes and challenges in clinical trials for these diseases; take a detailed look at recent developments in CAR T therapies for B cell malignancies; and describe how personalized antigen targeting can be applied to immunotherapeutic treatment of blood malignancies.
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Copyright © 2020 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)