Top read articles in the last 30 days
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Abstract
Four different endemic coronaviruses (eCoVs) are etiologic agents for the seasonal “common cold,” and these eCoVs share extensive sequence homology with human severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Here, we show that individuals with as compared to without a relatively recent documented eCoV were tested at greater frequency for respiratory infections but had similar rate of SARS-CoV-2 acquisition. Importantly, the patients with a previously detected eCoV had less severe coronavirus disease-2019 (COVID-19) illness. Our observations suggest that pre-existing immune responses against endemic human coronaviruses can mitigate disease manifestations from SARS-CoV-2 infection.
Authors
Manish Sagar, Katherine Reifler, Michael Rossi, Nancy S. Miller, Pranay Sinha, Laura White, Joseph P. Mizgerd
Total views: 10356
Abstract
BACKGROUND. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused over one million deaths worldwide, thus there is an urgent need to develop preventive and therapeutic strategies. The anti-tuberculosis vaccine Bacillus Calmette-Guérin (BCG) demonstrates non-specific protective innate immune-boosting effects. Here, we determined if history of BCG vaccination was associated with decreased SARS-CoV-2 infection and seroconversion in a retrospective observational study of a diverse cohort of health care workers (HCWs). METHODS. We assessed SARS-CoV-2 seroprevalence and collected medical questionnaires, including BCG vaccination status and pre-existing demographic and clinical characteristics, from an observational cohort of HCWs in a multi-site Los Angeles healthcare organization. We used multi-variate analysis to estimate if history of BCG vaccination was associated with decreased rates of SARS-CoV-2 infection and seroconversion. RESULTS. Of the 6,201 HCWs, 29.6% reported a history of BCG vaccination whereas 68.9% did not receive BCG vaccination. Seroprevalence of anti-SARS-CoV-2 IgG as well as incidence of self-reported clinical symptoms associated with COVID-19 were significantly decreased among HCWs with a history of BCG vaccination compared to those without BCG vaccination. After adjusting for age and sex, we found that history of BCG vaccination, but not meningococcal, pneumococcal or influenza vaccination, was associated with decreased SARS-CoV-2 IgG seroconversion. CONCLUSIONS. History of BCG vaccination was associated with decreased seroprevalence of anti-SARS-CoV-2 IgG and reduced reported COVID-19-related clinical symptoms in this cohort of HCWs. Therefore, large randomized prospective clinical trials of BCG vaccination are urgently needed to confirm if BCG vaccination can induced a protective effect against SARS-CoV2 infection. FUNDING. This work was supported by the National Institutes of Health, National Cancer Institute (U54 CA26059) and the Erika J. Glazer Family Foundation. Key words: SARS-CoV-2, COVID-19, Bacillus Calmette-Guérin, BCG, anti-SARS-CoV-2 IgG, healthcare workers, trained immunity.
Authors
Magali Noval Rivas, Joseph E. Ebinger, Min Wu, Nancy Sun, Jonathan Braun, Kimia Sobhani, Jennifer E. Van Eyk, Susan Cheng, Moshe Arditi
Total views: 7775
Abstract
The SARS-CoV-2 novel coronavirus global pandemic (COVID-19) has led to millions of cases and hundreds of thousands of deaths globally. While older adults appear at high risk for severe disease, hospitalizations and deaths due to SARS-CoV-2 among children have been relatively rare. Integrating single-cell RNA sequencing (scRNA-seq) of developing mouse lung with temporally-resolved immunofluorescence in mouse and human lung tissue, we found expression of SARS-CoV-2 Spike protein primer TMPRSS2 was highest in ciliated cells and type I alveolar epithelial cells (AT1), and TMPRSS2 expression increased with aging in mice and humans. Analysis of autopsy tissue from fatal COVID-19 cases detected SARS-CoV-2 RNA most frequently in ciliated and secretory cells in airway epithelium and AT1 cells in peripheral lung. SARS-CoV-2 RNA was highly colocalized in cells expressing TMPRSS2. Together, these data demonstrate the cellular spectrum infected by SARS-CoV-2 in lung epithelium and suggest that developmental regulation of TMPRSS2 may underlie the relative protection of infants and children from severe respiratory illness.
Authors
Bryce A. Schuler, A. Christian Habermann, Erin J. Plosa, Chase J. Taylor, Christopher Jetter, Nicholas M. Negretti, Meghan E. Kapp, John T. Benjamin, Peter Gulleman, David S. Nichols, Lior Z. Braunstein, Alice Hackett, Michael Koval, Susan H. Guttentag, Timothy S. Blackwell, Steven A. Webber, Nicholas E. Banovich, Jonathan A. Kropski, Jennifer M. S. Sucre
Total views: 3103
Abstract
By restoring glucose-regulated insulin secretion, glucagon-like peptide-1–based (GLP-1–based) therapies are becoming increasingly important in diabetes care. Normally, the incretins GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) jointly maintain normal blood glucose levels by stimulation of insulin secretion in pancreatic β cells. However, the reason why only GLP-1–based drugs are effective in improving insulin secretion after presentation of diabetes has not been resolved. ATP-sensitive K+ (KATP) channels play a crucial role in coupling the systemic metabolic status to β cell electrical activity for insulin secretion. Here, we have shown that persistent membrane depolarization of β cells due to genetic (β cell–specific Kcnj11–/– mice) or pharmacological (long-term exposure to sulfonylureas) inhibition of the KATP channel led to a switch from Gs to Gq in a major amplifying pathway of insulin secretion. The switch determined the relative insulinotropic effectiveness of GLP-1 and GIP, as GLP-1 can activate both Gq and Gs, while GIP only activates Gs. The findings were corroborated in other models of persistent depolarization: a spontaneous diabetic KK-Ay mouse and nondiabetic human and mouse β cells of pancreatic islets chronically treated with high glucose. Thus, a Gs/Gq signaling switch in β cells exposed to chronic hyperglycemia underlies the differential insulinotropic potential of incretins in diabetes.
Authors
Okechi S. Oduori, Naoya Murao, Kenju Shimomura, Harumi Takahashi, Quan Zhang, Haiqiang Dou, Shihomi Sakai, Kohtaro Minami, Belen Chanclon, Claudia Guida, Lakshmi Kothegala, Johan Tolö, Yuko Maejima, Norihide Yokoi, Yasuhiro Minami, Takashi Miki, Patrik Rorsman, Susumu Seino
Total views: 2723
Abstract
Neonatal diabetes is caused by single gene mutations reducing pancreatic β cell number or impairing β cell function. Understanding the genetic basis of rare diabetes subtypes highlights fundamental biological processes in β cells. We identified 6 patients from 5 families with homozygous mutations in the YIPF5 gene, which is involved in trafficking between the endoplasmic reticulum (ER) and the Golgi. All patients had neonatal/early-onset diabetes, severe microcephaly, and epilepsy. YIPF5 is expressed during human brain development, in adult brain and pancreatic islets. We used 3 human β cell models (YIPF5 silencing in EndoC-βH1 cells, YIPF5 knockout and mutation knockin in embryonic stem cells, and patient-derived induced pluripotent stem cells) to investigate the mechanism through which YIPF5 loss of function affects β cells. Loss of YIPF5 function in stem cell–derived islet cells resulted in proinsulin retention in the ER, marked ER stress, and β cell failure. Partial YIPF5 silencing in EndoC-βH1 cells and a patient mutation in stem cells increased the β cell sensitivity to ER stress–induced apoptosis. We report recessive YIPF5 mutations as the genetic cause of a congenital syndrome of microcephaly, epilepsy, and neonatal/early-onset diabetes, highlighting a critical role of YIPF5 in β cells and neurons. We believe this is the first report of mutations disrupting the ER-to-Golgi trafficking, resulting in diabetes.
Authors
Elisa De Franco, Maria Lytrivi, Hazem Ibrahim, Hossam Montaser, Matthew N. Wakeling, Federica Fantuzzi, Kashyap Patel, Céline Demarez, Ying Cai, Mariana Igoillo-Esteve, Cristina Cosentino, Väinö Lithovius, Helena Vihinen, Eija Jokitalo, Thomas W. Laver, Matthew B. Johnson, Toshiaki Sawatani, Hadis Shakeri, Nathalie Pachera, Belma Haliloglu, Mehmet Nuri Ozbek, Edip Unal, Ruken Yıldırım, Tushar Godbole, Melek Yildiz, Banu Aydin, Angeline Bilheu, Ikuo Suzuki, Sarah E. Flanagan, Pierre Vanderhaeghen, Valérie Senée, Cécile Julier, Piero Marchetti, Decio L. Eizirik, Sian Ellard, Jonna Saarimäki-Vire, Timo Otonkoski, Miriam Cnop, Andrew T. Hattersley
Total views: 2527
Abstract
BACKGROUND Since December 2019, an outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, and is now becoming a global threat. We aimed to delineate and compare the immunological features of severe and moderate COVID-19.METHODS In this retrospective study, the clinical and immunological characteristics of 21 patients (17 male and 4 female) with COVID-19 were analyzed. These patients were classified as severe (11 cases) and moderate (10 cases) according to the guidelines released by the National Health Commission of China.RESULTS The median age of severe and moderate cases was 61.0 and 52.0 years, respectively. Common clinical manifestations included fever, cough, and fatigue. Compared with moderate cases, severe cases more frequently had dyspnea, lymphopenia, and hypoalbuminemia, with higher levels of alanine aminotransferase, lactate dehydrogenase, C-reactive protein, ferritin, and D-dimer as well as markedly higher levels of IL-2R, IL-6, IL-10, and TNF-α. Absolute numbers of T lymphocytes, CD4+ T cells, and CD8+ T cells decreased in nearly all the patients, and were markedly lower in severe cases (294.0, 177.5, and 89.0 × 106/L, respectively) than moderate cases (640.5, 381.5, and 254.0 × 106/L, respectively). The expression of IFN-γ by CD4+ T cells tended to be lower in severe cases (14.1%) than in moderate cases (22.8%).CONCLUSION The SARS-CoV-2 infection may affect primarily T lymphocytes, particularly CD4+ and CD8+ T cells, resulting in a decrease in numbers as well as IFN-γ production by CD4+ T cells. These potential immunological markers may be of importance because of their correlation with disease severity in COVID-19.TRIAL REGISTRATION This is a retrospective observational study without a trial registration number.FUNDING This work is funded by grants from Tongji Hospital for the Pilot Scheme Project, and partly supported by the Chinese National Thirteenth Five Years Project in Science and Technology for Infectious Disease (2017ZX10202201).
Authors
Guang Chen, Di Wu, Wei Guo, Yong Cao, Da Huang, Hongwu Wang, Tao Wang, Xiaoyun Zhang, Huilong Chen, Haijing Yu, Xiaoping Zhang, Minxia Zhang, Shiji Wu, Jianxin Song, Tao Chen, Meifang Han, Shusheng Li, Xiaoping Luo, Jianping Zhao, Qin Ning
Total views: 2385
Abstract
Tregs require Foxp3 expression and induction of a specific DNA hypomethylation signature during development, after which Tregs persist as a self-renewing population that regulates immune system activation. Whether maintenance DNA methylation is required for Treg lineage development and stability and how methylation patterns are maintained during lineage self-renewal remain unclear. Here, we demonstrate that the epigenetic regulator ubiquitin-like with plant homeodomain and RING finger domains 1 (Uhrf1) is essential for maintenance of methyl-DNA marks that stabilize Treg cellular identity by repressing effector T cell transcriptional programs. Constitutive and induced deficiency of Uhrf1 within Foxp3+ cells resulted in global yet nonuniform loss of DNA methylation, derepression of inflammatory transcriptional programs, destabilization of the Treg lineage, and spontaneous inflammation. These findings support a paradigm in which maintenance DNA methylation is required in distinct regions of the Treg genome for both lineage establishment and stability of identity and suppressive function.
Authors
Kathryn A. Helmin, Luisa Morales-Nebreda, Manuel A. Torres Acosta, Kishore R. Anekalla, Shang-Yang Chen, Hiam Abdala-Valencia, Yuliya Politanska, Paul Cheresh, Mahzad Akbarpour, Elizabeth M. Steinert, Samuel E. Weinberg, Benjamin D. Singer
Total views: 2315
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent for coronavirus 2019 (COVID-19) pneumonia. Little is known about the kinetics, tissue distribution, cross-reactivity, and neutralization antibody response in patients with COVID-19. Two groups of patients with RT-PCR–confirmed COVID-19 were enrolled in this study: 12 severely ill patients in intensive care units who needed mechanical ventilation and 11 mildly ill patients in isolation wards. Serial clinical samples were collected for laboratory detection. Results showed that most of the severely ill patients had viral shedding in a variety of tissues for 20–40 days after onset of disease (8/12, 66.7%), while the majority of mildly ill patients had viral shedding restricted to the respiratory tract and had no detectable virus RNA 10 days after onset (9/11, 81.8%). Mildly ill patients showed significantly lower IgM response compared with that of the severe group. IgG responses were detected in most patients in both the severe and mild groups at 9 days after onset, and remained at a high level throughout the study. Antibodies cross-reactive to SARS-CoV and SARS-CoV-2 were detected in patients with COVID-19 but not in patients with MERS. High levels of neutralizing antibodies were induced after about 10 days after onset in both severely and mildly ill patients which were higher in the severe group. SARS-CoV-2 pseudotype neutralization test and focus reduction neutralization test with authentic virus showed consistent results. Sera from patients with COVID-19 inhibited SARS-CoV-2 entry. Sera from convalescent patients with SARS or Middle East respiratory syndrome (MERS) did not. Anti–SARS-CoV-2 S and N IgG levels exhibited a moderate correlation with neutralization titers in patients’ plasma. This study improves our understanding of immune response in humans after SARS-CoV-2 infection.
Authors
Yanqun Wang, Lu Zhang, Ling Sang, Feng Ye, Shicong Ruan, Bei Zhong, Tie Song, Abeer N. Alshukairi, Rongchang Chen, Zhaoyong Zhang, Mian Gan, Airu Zhu, Yongbo Huang, Ling Luo, Chris Ka Pun Mok, Manal M. Al Gethamy, Haitao Tan, Zhengtu Li, Xiaofang Huang, Fang Li, Jing Sun, Yanjun Zhang, Liyan Wen, Yuming Li, Zhao Chen, Zhen Zhuang, Jianfen Zhuo, Chunke Chen, Lijun Kuang, Junxiang Wang, Huibin Lv, Yongliang Jiang, Min Li, Yimin Lin, Ying Deng, Lan Tang, Jieling Liang, Jicheng Huang, Stanley Perlman, Nanshan Zhong, Jingxian Zhao, J.S. Malik Peiris, Yimin Li, Jincun Zhao
Total views: 2153
Abstract
BACKGROUND Serological assays are of critical importance to investigate correlates of response and protection in coronavirus disease 2019 (COVID-19), to define previous exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in populations, and to verify the development of an adaptive immune response in infected individuals.METHODS We studied 509 patients confirmed to have COVID-19 from the San Raffaele Hospital of Milan and 480 samples of prepandemic organ donor sera collected in 2010–2012. Using fluid-phase luciferase immune precipitation (LIPS) assays, we characterized IgG, IgM, and IgA antibodies to the spike receptor binding domain (RBD), S1+S2, nucleocapsid, and ORF6 to ORF10 of SARS-CoV-2, to the HCoV-OC43 and HCoV-HKU1 betacoronaviruses spike S2, and the H1N1Ca2009 flu virus hemagglutinin. Sequential samples at 1 and 3 months after hospital discharge were also tested for SARS-CoV-2 RBD antibodies in 95 patients.RESULTS Antibodies developed rapidly against multiple SARS-CoV-2 antigens in 95% of patients by 4 weeks after symptom onset and IgG to the RBD increased until the third month of follow-up. We observed a major synchronous expansion of antibodies to the HCoV-OC43 and HCoV-HKU1 spike S2. A likely coinfection with influenza was neither linked to a more severe presentation of the disease nor to a worse outcome. Of the measured antibody responses, positivity for IgG against the SARS-CoV-2 spike RBD was predictive of survival.CONCLUSION The measurement of antibodies to selected epitopes of SARS-CoV-2 antigens can offer a more accurate assessment of the humoral response in patients and its impact on survival. The presence of partially cross-reactive antibodies with other betacoronaviruses is likely to impact on serological assay specificity and interpretation.TRIAL REGISTRATION COVID-19 Patients Characterization, Biobank, Treatment Response and Outcome Predictor (COVID-BioB). ClinicalTrials.gov identifier: NCT04318366.FUNDING IRCCS Ospedale San Raffaele and Università Vita Salute San Raffaele.
Authors
Massimiliano Secchi, Elena Bazzigaluppi, Cristina Brigatti, Ilaria Marzinotto, Cristina Tresoldi, Patrizia Rovere-Querini, Andrea Poli, Antonella Castagna, Gabriella Scarlatti, Alberto Zangrillo, Fabio Ciceri, Lorenzo Piemonti, Vito Lampasona
Total views: 2121
Abstract
BACKGROUND Data from studies conducted in rodent models have shown that decreased adipose tissue (AT) oxygenation is involved in the pathogenesis of obesity-induced insulin resistance. Here, we evaluated the potential influence of AT oxygenation on AT biology and insulin sensitivity in people.METHODS We evaluated subcutaneous AT oxygen partial pressure (pO2); liver and whole-body insulin sensitivity; AT expression of genes and pathways involved in inflammation, fibrosis, and branched-chain amino acid (BCAA) catabolism; systemic markers of inflammation; and plasma BCAA concentrations, in 3 groups of participants that were rigorously stratified by adiposity and insulin sensitivity: metabolically healthy lean (MHL; n = 11), metabolically healthy obese (MHO; n = 15), and metabolically unhealthy obese (MUO; n = 20).RESULTS AT pO2 progressively declined from the MHL to the MHO to the MUO group, and was positively associated with hepatic and whole-body insulin sensitivity. AT pO2 was positively associated with the expression of genes involved in BCAA catabolism, in conjunction with an inverse relationship between AT pO2 and plasma BCAA concentrations. AT pO2 was negatively associated with AT gene expression of markers of inflammation and fibrosis. Plasma PAI-1 increased from the MHL to the MHO to the MUO group and was negatively correlated with AT pO2, whereas the plasma concentrations of other cytokines and chemokines were not different among the MHL and MUO groups.CONCLUSION These results support the notion that reduced AT oxygenation in individuals with obesity contributes to insulin resistance by increasing plasma PAI-1 concentrations and decreasing AT BCAA catabolism and thereby increasing plasma BCAA concentrations.TRIAL REGISTRATION ClinicalTrials.gov NCT02706262.FUNDING This study was supported by NIH grants K01DK109119, T32HL130357, K01DK116917, R01ES027595, P42ES010337, DK56341 (Nutrition Obesity Research Center), DK20579 (Diabetes Research Center), DK052574 (Digestive Disease Research Center), and UL1TR002345 (Clinical and Translational Science Award); NIH Shared Instrumentation Grants S10RR0227552, S10OD020025, and S10OD026929; and the Foundation for Barnes-Jewish Hospital.
Authors
Vincenza Cifarelli, Scott C. Beeman, Gordon I. Smith, Jun Yoshino, Darya Morozov, Joseph W. Beals, Brandon D. Kayser, Jeramie D. Watrous, Mohit Jain, Bruce W. Patterson, Samuel Klein
Total views: 2096
Abstract
Human coronaviruses (hCoVs) cause severe respiratory illness in the elderly. Age-related impairments in innate immunity and suboptimal virus-specific T cell and antibody responses are believed to cause severe disease upon respiratory virus infections. This phenomenon has recently received increased attention, as elderly patients are at substantially elevated risk for severe COVID-19 disease and experience increased rates of mortality following SARS-CoV-2 infection compared with younger populations. However, the basis for age-related fatal pneumonia following pathogenic hCoVs is not well understood. In this Review, we provide an overview of our current understanding of hCoV-induced fatal pneumonia in the elderly. We describe host immune response to hCoV infections derived from studies of young and aged animal models and discuss the potential role of age-associated increases in sterile inflammation (inflammaging) and virus-induced dysregulated inflammation in causing age-related severe disease. We also highlight the existing gaps in our knowledge about virus replication and host immune responses to hCoV infection in young and aged individuals.
Authors
Rudragouda Channappanavar, Stanley Perlman
Total views: 2437
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS–CoV-2), the cause of coronavirus disease 2019 (COVID-19), has spurred a global health crisis. To date, there are no proven options for prophylaxis for those who have been exposed to SARS–CoV-2, nor therapy for those who develop COVID-19. Immune (i.e., “convalescent”) plasma refers to plasma that is collected from individuals following resolution of infection and development of antibodies. Passive antibody administration through transfusion of convalescent plasma may offer the only short-term strategy for conferring immediate immunity to susceptible individuals. There are numerous examples in which convalescent plasma has been used successfully as postexposure prophylaxis and/or treatment of infectious diseases, including other outbreaks of coronaviruses (e.g., SARS-1, Middle East respiratory syndrome [MERS]). Convalescent plasma has also been used in the COVID-19 pandemic; limited data from China suggest clinical benefit, including radiological resolution, reduction in viral loads, and improved survival. Globally, blood centers have robust infrastructure for undertaking collections and constructing inventories of convalescent plasma to meet the growing demand. Nonetheless, there are nuanced challenges, both regulatory and logistical, spanning donor eligibility, donor recruitment, collections, and transfusion itself. Data from rigorously controlled clinical trials of convalescent plasma are also few, underscoring the need to evaluate its use objectively for a range of indications (e.g., prevention vs. treatment) and patient populations (e.g., age, comorbid disease). We provide an overview of convalescent plasma, including evidence of benefit, regulatory considerations, logistical work flow, and proposed clinical trials, as scale-up is brought underway to mobilize this critical resource.
Authors
Evan M. Bloch, Shmuel Shoham, Arturo Casadevall, Bruce S. Sachais, Beth Shaz, Jeffrey L. Winters, Camille van Buskirk, Brenda J. Grossman, Michael Joyner, Jeffrey P. Henderson, Andrew Pekosz, Bryan Lau, Amy Wesolowski, Louis Katz, Hua Shan, Paul G. Auwaerter, David Thomas, David J. Sullivan, Nigel Paneth, Eric Gehrie, Steven Spitalnik, Eldad A. Hod, Lewis Pollack, Wayne T. Nicholson, Liise-anne Pirofski, Jeffrey A. Bailey, Aaron A.R. Tobian
Total views: 1779
Abstract
Muscular dystrophies are debilitating disorders that result in progressive weakness and degeneration of skeletal muscle. Although the genetic mutations and clinical abnormalities of a variety of neuromuscular diseases are well known, no curative therapies have been developed to date. The advent of genome editing technology provides new opportunities to correct the underlying mutations responsible for many monogenic neuromuscular diseases. For example, Duchenne muscular dystrophy, which is caused by mutations in the dystrophin gene, has been successfully corrected in mice, dogs, and human cells through CRISPR/Cas9 editing. In this Review, we focus on the potential for, and challenges of, correcting muscular dystrophies by editing disease-causing mutations at the genomic level. Ideally, because muscle tissues are extremely long-lived, CRISPR technology could offer a one-time treatment for muscular dystrophies by correcting the culprit genomic mutations and enabling normal expression of the repaired gene.
Authors
Francesco Chemello, Rhonda Bassel-Duby, Eric N. Olson
Total views: 770
Abstract
Androgens and estrogens are known to be critical regulators of mammalian physiology and development. While these two classes of steroids share similar structures (in general, estrogens are derived from androgens via the enzyme aromatase), they subserve markedly different functions via their specific receptors. In the past, estrogens such as estradiol were thought to be most important in the regulation of female biology, while androgens such as testosterone and dihydrotestosterone were believed to primarily modulate development and physiology in males. However, the emergence of patients with deficiencies in androgen or estrogen hormone synthesis or actions, as well as the development of animal models that specifically target androgen- or estrogen-mediated signaling pathways, have revealed that estrogens and androgens regulate critical biological and pathological processes in both males and females. In fact, the concept of “male” and “female” hormones is an oversimplification of a complex developmental and biological network of steroid actions that directly impacts many organs. In this Review, we will discuss important roles of estrogens in males and androgens in females.
Authors
Stephen R. Hammes, Ellis R. Levin
Total views: 765
Abstract
Muscular dystrophies are a heterogeneous group of genetic diseases, characterized by progressive degeneration of skeletal and cardiac muscle. Despite the intense investigation of different therapeutic options, a definitive treatment has not been developed for this debilitating class of pathologies. Cell-based therapies in muscular dystrophies have been pursued experimentally for the last three decades. Several cell types with different characteristics and tissues of origin, including myogenic stem and progenitor cells, stromal cells, and pluripotent stem cells, have been investigated over the years and have recently entered in the clinical arena with mixed results. In this Review, we do a roundup of the past attempts and describe the updated status of cell-based therapies aimed at counteracting the skeletal and cardiac myopathy present in dystrophic patients. We present current challenges, summarize recent progress, and make recommendations for future research and clinical trials.
Authors
Stefano Biressi, Antonio Filareto, Thomas A. Rando
Total views: 678
Abstract
Macrophages are tissue-resident or infiltrated immune cells critical for innate immunity, normal tissue development, homeostasis, and repair of damaged tissue. Macrophage function is a sum of their ontogeny, the local environment in which they reside, and the type of injuries or pathogen to which they are exposed. In this Review, we discuss the role of macrophages in the restoration of tissue function after injury, highlighting important questions about how they respond to and modify the local microenvironment to restore homeostasis.
Authors
Satoshi Watanabe, Michael Alexander, Alexander V. Misharin, G.R. Scott Budinger
Total views: 630
Abstract
Although obesity is typically associated with metabolic dysfunction and cardiometabolic diseases, some people with obesity are protected from many of the adverse metabolic effects of excess body fat and are considered “metabolically healthy.” However, there is no universally accepted definition of metabolically healthy obesity (MHO). Most studies define MHO as having either 0, 1, or 2 metabolic syndrome components, whereas many others define MHO using the homeostasis model assessment of insulin resistance (HOMA-IR). Therefore, numerous people reported as having MHO are not metabolically healthy, but simply have fewer metabolic abnormalities than those with metabolically unhealthy obesity (MUO). Nonetheless, a small subset of people with obesity have a normal HOMA-IR and no metabolic syndrome components. The mechanism(s) responsible for the divergent effects of obesity on metabolic health is not clear, but studies conducted in rodent models suggest that differences in adipose tissue biology in response to weight gain can cause or prevent systemic metabolic dysfunction. In this article, we review the definition, stability over time, and clinical outcomes of MHO, and discuss the potential factors that could explain differences in metabolic health in people with MHO and MUO — specifically, modifiable lifestyle factors and adipose tissue biology. Better understanding of the factors that distinguish people with MHO and MUO can produce new insights into mechanism(s) responsible for obesity-related metabolic dysfunction and disease.
Authors
Gordon I. Smith, Bettina Mittendorfer, Samuel Klein
Total views: 596
Abstract
Epithelial cell dysfunction has emerged as a central component of the pathophysiology of diffuse parenchymal diseases including idiopathic pulmonary fibrosis (IPF). Alveolar type 2 (AT2) cells represent a metabolically active lung cell population important for surfactant biosynthesis and alveolar homeostasis. AT2 cells and other distal lung epithelia, like all eukaryotic cells, contain an elegant quality control network to respond to intrinsic metabolic and biosynthetic challenges imparted by mutant protein conformers, dysfunctional subcellular organelles, and dysregulated telomeres. Failed AT2 quality control components (the ubiquitin-proteasome system, unfolded protein response, macroautophagy, mitophagy, and telomere maintenance) result in diverse cellular endophenotypes and molecular signatures including ER stress, defective autophagy, mitochondrial dysfunction, apoptosis, inflammatory cell recruitment, profibrotic signaling, and altered progenitor function that ultimately converge to drive downstream fibrotic remodeling in the IPF lung. As this complex network becomes increasingly better understood, opportunities will emerge to identify targets and therapeutic strategies for IPF.
Authors
Jeremy Katzen, Michael F. Beers
Total views: 582
Abstract
Pulmonary hypertension (PH) is characterized by pulmonary artery remodeling that can subsequently culminate in right heart failure and premature death. Emerging evidence suggests that hypoxia-inducible factor (HIF) signaling plays a fundamental and pivotal role in the pathogenesis of PH. This Review summarizes the regulation of HIF isoforms and their impact in various PH subtypes, as well as the elaborate conditional and cell-specific knockout mouse studies that brought the role of this pathway to light. We also discuss the current preclinical status of pan- and isoform-selective HIF inhibitors, and propose new research areas that may facilitate HIF isoform-specific inhibition as a novel therapeutic strategy for PH and right heart failure.
Authors
Soni Savai Pullamsetti, Argen Mamazhakypov, Norbert Weissmann, Werner Seeger, Rajkumar Savai
Total views: 553
Abstract
The metabolic syndrome (MetS) is a constellation of risk factors that, if left untreated, will often progress to greater metabolic defects such as type 2 diabetes and nonalcoholic fatty liver disease. While these risk factors have been established for over 40 years, the definition of MetS warrants reconsideration in light of the substantial data that have emerged from studies of the gut microbiome. In this Review we present the existing recent literature that supports the gut microbiome’s potential influence on the various risk factors of MetS. The interplay of the intestinal microbiota with host metabolism has been shown to be mediated by a myriad of factors, including a defective gut barrier, bile acid metabolism, antibiotic use, and the pleiotropic effects of microbially produced metabolites. These data show that events that start in the gut, often in response to external cues such as diet and circadian disruption, have far-reaching effects beyond the gut.
Authors
Kruttika Dabke, Gustaf Hendrick, Suzanne Devkota
Total views: 540
Copyright © 2020 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)