Inflammation
Abstract
Long noncoding RNAs (lncRNAs) are increasingly implicated in the pathology of diabetic complications. Here we examined the role of lncRNAs in monocyte dysfunction and inflammation associated with human type 2 diabetes mellitus (T2D). RNA-seq analysis of CD14+ monocytes from patients with T2D versus healthy controls revealed downregulation of anti-inflammatory and anti-proliferative genes along with several lncRNAs, including a novel divergent lncRNA DRAIR (Diabetes Regulated anti-inflammatory RNA) and its nearby gene CPEB2. High glucose and palmitic acid downregulated DRAIR in cultured CD14+ monocytes, whereas anti-inflammatory cytokines and monocyte-to-macrophage differentiation upregulated DRAIR via KLF4 transcription factor. DRAIR overexpression increased anti-inflammatory and macrophage differentiation genes but inhibited pro-inflammatory genes. Conversely, DRAIR knockdown attenuated anti-inflammatory genes, promoted inflammatory responses, and inhibited phagocytosis. DRAIR regulated target gene expression through interaction with chromatin, and inhibition of the repressive epigenetic mark H3K9me2 and its corresponding methyltransferase G9a. Mouse orthologous Drair and Cpeb2 were also downregulated in peritoneal macrophages from T2D db/db mice, and Drair knockdown in non-diabetic mice enhanced pro-inflammatory genes in macrophages. Thus, DRAIR modulates inflammatory phenotype of monocytes/macrophages via epigenetic mechanisms, and its downregulation in T2D may promote chronic inflammation. Augmentation of endogenous lncRNAs like DRAIR could serve as novel anti-inflammatory therapies for diabetic complications.
Authors
Marpadga A. Reddy, Vishnu Amaram, Sadhan Das, Vinay Singh Tanwar, Rituparna Ganguly, Mei Wang, Linda Lanting, Linxiao Zhang, Maryam Abdollahi, Zhuo Chen, Xiwei Wu, Sridevi Devaraj, Rama Natarajan
Abstract
Virus-induced respiratory tract infections are a major health burden in childhood, and available treatments are supportive rather than disease modifying. Rhinoviruses (RVs), the cause of approximately 80% of common colds, are detected in nearly half of all infants with bronchiolitis and the majority of children with an asthma exacerbation. Bronchiolitis in early life is a strong risk factor for the development of asthma. Here, we found that RV infection induced the expression of miRNA 122 (miR-122) in mouse lungs and in human airway epithelial cells. In vivo inhibition specifically in the lung reduced neutrophilic inflammation and CXCL2 expression, boosted innate IFN responses, and ameliorated airway hyperreactivity in the absence and in the presence of allergic lung inflammation. Inhibition of miR-122 in the lung increased the levels of suppressor of cytokine signaling 1 (SOCS1), which is an in vitro–validated target of miR-122. Importantly, gene silencing of SOCS1 in vivo completely reversed the protective effects of miR-122 inhibition on RV-induced lung disease. Higher miR-122 expression in nasopharyngeal aspirates was associated with a longer time on oxygen therapy and a higher rate of treatment failure in 87 infants hospitalized with moderately severe bronchiolitis. These results suggest that miR-122 promotes RV-induced lung disease via suppression of its target SOCS1 in vivo. Higher miR-122 expression was associated with worse clinical outcomes, highlighting the potential use of anti-miR-122 oligonucleotides, successfully trialed for treatment of hepatitis C, as potential therapeutics for RV-induced bronchiolitis and asthma exacerbations.
Authors
Adam M. Collison, Leon A. Sokulsky, Elizabeth Kepreotes, Ana Pereira de Siqueira, Matthew Morten, Michael R. Edwards, Ross P. Walton, Nathan W. Bartlett, Ming Yang, Thi Hiep Nguyen, Sebastian L. Johnston, Paul S. Foster, Joerg Mattes
Abstract
Proline-glycine-proline (PGP) and its acetylated form (Ac-PGP) are neutrophil chemoattractants generated by collagen degradation, and they have been shown to play a role in chronic inflammatory disease. However, the mechanism for matrikine regulation in acute inflammation has not been well established. Here, we show that these peptides are actively transported from the lung by the oligopeptide transporter, PEPT2. Following intratracheal instillation of Ac-PGP in a mouse model, there was a rapid decline in concentration of the labeled peptide in the bronchoalveolar lavage (BAL) over time and redistribution to extrapulmonary sites. In vitro knockdown of the PEPT2 transporter in airway epithelia or use of a competitive inhibitor of PEPT2, cefadroxil, significantly reduced uptake of Ac-PGP. Animals that received intratracheal Ac-PGP plus cefadroxil had higher levels of Ac-PGP in BAL and lung tissue. Utilizing an acute LPS-induced lung injury model, we demonstrate that PEPT2 blockade enhanced pulmonary Ac-PGP levels and lung inflammation. We further validated this effect using clinical samples from patients with acute lung injury in coculture with airway epithelia. This is the first study to our knowledge to determine the in vitro and in vivo significance of active matrikine transport as a mechanism of modulating acute inflammation and to demonstrate that it may serve as a potential therapeutic target.
Authors
Sarah W. Robison, JinDong Li, Liliana Viera, Jonathan P. Blackburn, Rakesh P. Patel, J. Edwin Blalock, Amit Gaggar, Xin Xu
Abstract
The Janus kinase/signal transducers and activators of transcription (JAK/STAT) are key intracellular mediators in the signal transduction of many cytokines and growth factors. Common γ chain cytokines and interferon-γ that use the JAK/STAT pathway to induce biological responses have been implicated in the pathogenesis of alopecia areata (AA), a T cell–mediated autoimmune disease of the hair follicle. We previously showed that therapeutic targeting of JAK/STAT pathways using the first-generation JAK1/2 inhibitor, ruxolitinib, and the pan-JAK inhibitor, tofacitinib, was highly effective in the treatment of human AA, as well as prevention and reversal of AA in the C3H/HeJ mouse model. To better define the role of individual JAKs in the pathogenesis of AA, in this study, we tested and compared the efficacy of several next-generation JAK-selective inhibitors in the C3H/HeJ mouse model of AA, using both systemic and topical delivery. We found that JAK1-selective inhibitors as well as JAK3-selective inhibitors robustly induced hair regrowth and decreased AA-associated inflammation, whereas several JAK2-selective inhibitors failed to restore hair growth in treated C3H/HeJ mice with AA. Unlike JAK1, which is broadly expressed in many tissues, JAK3 expression is largely restricted to hematopoietic cells. Our study demonstrates inhibiting JAK3 signaling is sufficient to prevent and reverse disease in the preclinical model of AA.
Authors
Zhenpeng Dai, James Chen, Yuqian Chang, Angela M. Christiano
Abstract
Anastomotic leakage (AL) accounts for a major part of in-house mortality in patients undergoing colorectal surgery. Local ischemia and abdominal sepsis are common risk factors contributing to AL and are characterized by upregulation of the hypoxia-inducible factor (HIF) pathway. The HIF pathway is critically regulated by HIF-prolyl hydroxylases (PHDs). Here, we investigated the significance of PHDs and the effects of pharmacologic PHD inhibition (PHI) during anastomotic healing. Ischemic or septic colonic anastomoses were created in mice by ligation of mesenteric vessels or lipopolysaccharide-induced abdominal sepsis, respectively. Genetic PHD-deficiency (Phd1-/-, Phd2+/-, and Phd3-/-) or PHI were applied to manipulate PHD activity. Pharmacologic PHI and genetic PHD2-haplodeficiency (Phd2+/-) significantly improved healing of ischemic or septic colonic anastomoses, as indicated by increased bursting pressure and reduced AL rates. Only Phd2+/- (but not PHI or Phd1-/-) protected from sepsis-related mortality. Mechanistically, PHI and Phd2+/- induced immuno-modulatory (M2) polarization of macrophages, resulting in increased collagen content and attenuated inflammation-driven immune cell recruitment. We conclude that PHI improves healing of colonic anastomoses in ischemic or septic conditions by Phd2+/--mediated M2 polarization of macrophages, conferring a favourable microenvironment for anastomotic healing. Patients with critically perfused colorectal anastomosis or abdominal sepsis could benefit from pharmacologic PHI.
Authors
Moritz J. Strowitzki, Gwendolyn Kimmer, Julian S. Wehrmann, Alina S. Ritter, Praveen Radhakrishnan, Vanessa M. Opitz, Christopher Tuffs, Marvin Biller, Julia Kugler, Ulrich Keppler, Jonathan M. Harnoss, Johannes Klose, Thomas Schmidt, Alfonso Blanco, Cormac T. Taylor, Martin Schneider
Abstract
Despite studies implicating adipose tissue T cells (ATT) in the initiation and persistence of adipose tissue inflammation, fundamental gaps in knowledge regarding ATT function impedes progress towards understanding how obesity influences adaptive immunity. We hypothesized ATT activation and function would have tissue-resident specific properties and that obesity would potentiate their inflammatory properties. We assessed ATT activation and inflammatory potential within mouse and human stromal vascular fraction (SVF). Surprisingly, murine and human ATTs from obese visceral white adipose tissue exhibited impaired inflammatory characteristics. Both environmental and cell-intrinsic factors are implicated in ATT dysfunction. Soluble factors from obese SVF inhibit ATTs activation. Additionally, chronic signaling through the T cell receptor is necessary for ATT impairment in obese adipose tissue but is independent of increased PD1 expression. To assess intracellular signaling mechanisms responsible for ATT inflammation impairments, single-cell RNA sequencing of ATTs was performed. ATTs in obese adipose tissue exhibit gene expression resembling T cell exhaustion and increased expression of co-inhibitory receptor Btla. In sum, this work suggests that obesity-induced ATT cells have functional characteristics and gene expression resembling T cell exhaustion, which is dependent upon localized soluble factors and cell-to-cell interactions in adipose tissue.
Authors
Cara E. Porsche, Jennifer B. DelProposto, Lynn Geletka, Robert O’Rourke, Carey N. Lumeng
Abstract
Mounting evidence suggests that the balance of T cell costimulatory and coinhibitory signals contributes to mortality during sepsis. Here, we identified a critical role of the coinhibitory molecule T cell Ig and ITIM domain (TIGIT) in regulating sepsis mortality. Because TIGIT is significantly upregulated on memory T cells, we developed a “memory mouse” model to study the role of TIGIT during sepsis in a more physiologically relevant context. Mice received sequential pathogen exposure and developed memory T cell frequencies, similar to those observed in adult humans, and were then subjected to sepsis induction via cecal ligation and puncture. Our results show that targeting the TIGIT pathway during sepsis is fundamentally different in previously naive versus memory mice, in that αTIGIT Ab had no effect on survival in previously naive septic mice but sharply worsened survival in memory septic mice. Mechanistically, αTIGIT increased apoptosis of memory T cells, decreased T cell function, and downregulated the costimulatory receptor DNAM on memory CD8+ T cells in memory septic mice, but not in previously naive septic mice. Additionally, αTIGIT diminished Helios expression in Tregs in memory but not previously naive septic mice. These data highlight fundamental differences in the pathophysiological impact of targeting TIGIT in immunologically experienced versus previously naive hosts during sepsis.
Authors
Yini Sun, Jerome C. Anyalebechi, He Sun, Tetsuya Yumoto, Ming Xue, Danya Liu, Zhe Liang, Craig M. Coopersmith, Mandy L. Ford
Abstract
Introduction: Coronavirus 2019 (COVID-19) clinical course is heterogeneous, ranging from mild to severe multi-organ failure and death. In this study, we analyzed cell-free DNA (cfDNA) as a biomarker of injury to define the sources of tissue injury that contribute to such different trajectories. Methods: We conducted a multi-center prospective cohort study to enroll COVID-19 patients and collect plasma samples. Plasma cfDNA was subject to bisulfite sequencing. A library of tissue-specific DNA methylation signatures was used to analyze sequence reads to quantitate cfDNA from different tissue types. We then determined the correlation of tissue-specific cfDNA measures to COVID-19 outcomes. Similar analyses was performed for healthy controls and a comparator group of patients with respiratory syncytial virus and influenza. Results: We found markedly elevated levels and divergent tissue sources of cfDNA in COVID-19 patients compared to influenza and respiratory syncytial virus patients or healthy controls. The major sources of cfDNA in COVID-19 were hematopoietic cells, vascular endothelium, hepatocyte, adipocyte, kidney, heart and lung. cfDNA levels positively correlated with COVID-19 disease severity, c reactive protein, D-Dimer. cfDNA profile at admission identified patients who subsequently required intensive care or died during hospitalization. Furthermore, the increased cfDNA in COVID-19 patients generates excessive mitochondrial reactive oxygen species (mtROS) in renal tubular cells in a concentration-dependent manner. This mtROS production was inhibited by a toll-like receptor 9 (TLR-9)-specific antagonist. Conclusion cfDNA maps tissue injury that predict COVID-19 outcomes, and may mechanistically propagates COVID-19 induced tissue injury. Funding sources: Intramural Targeted Anti-COVID-19 grant, National Institutes of Health
Authors
Temesgen E. Andargie, Naoko Tsuji, Fayaz Seifuddin, Moon Kyoo Jang, Peter S.T. Yuen, Hyesik Kong, Ilker Tunc, Komudi Singh, Ananth Charya, Kenneth J. Wilkins, Steven D. Nathan, Andrea L. Cox, Mehdi Pirooznia, Robert A. Star, Sean Agbor-Enoh
Abstract
Hepatocellular death contributes to progression of alcohol–associated (ALD-associated) and non–alcohol-associated (NAFL/NASH) liver diseases. However, receptor-interaction protein kinase 3 (RIP3), an intermediate in necroptotic cell death, contributes to injury in murine models of ALD but not NAFL/NASH. We show here that a differential role for mixed-lineage kinase domain–like protein (MLKL), the downstream effector of RIP3, in murine models of ALD versus NAFL/NASH and that RIP1-RIP3-MLKL can be used as biomarkers to distinguish alcohol-associated hepatitis (AH) from NASH. Phospho-MLKL was higher in livers of patients with NASH compared with AH or healthy controls (HCs). MLKL expression, phosphorylation, oligomerization, and translocation to plasma membrane were induced in WT mice fed diets high in fat, fructose, and cholesterol but not in response to Gao-binge (acute on chronic) ethanol exposure. Mlkl–/– mice were not protected from ethanol-induced hepatocellular injury, which was associated with increased expression of chemokines and neutrophil recruitment. Circulating concentrations of RIP1 and RIP3, but not MLKL, distinguished patients with AH from HCs or patients with NASH. Taken together, these data indicate that MLKL is differentially activated in ALD/AH compared with NAFL/NASH in both murine models and patients. Furthermore, plasma RIP1 and RIP3 may be promising biomarkers for distinguishing AH and NASH.
Authors
Tatsunori Miyata, Xiaoqin Wu, Xiude Fan, Emily Huang, Carlos Sanz-Garcia, Christina K. Cajigas-Du Ross, Sanjoy Roychowdhury, Annette Bellar, Megan R. McMullen, Jaividhya Dasarathy, Daniela S. Allende, Joan Caballeria, Pau Sancho-Bru, Craig J. McClain, Mack Mitchell, Arthur J. McCullough, Svetlana Radaeva, Bruce Barton, Gyongyi Szabo, Srinivasan Dasarathy, Laura E. Nagy
Abstract
Cancer is caused primarily by genomic alterations resulting in deregulation of gene regulatory circuits in key growth, apoptosis or DNA repair pathways. Multiple genes associated with the initiation and development of tumors are also regulated at the level of mRNA decay, through the recruitment of RNA binding proteins to AU-rich elements (AREs) located in their 3’-untranslated regions. One of these ARE-binding proteins, tristetraprolin (TTP, encoded by Zfp36) is consistently dysregulated in many human malignancies. Herein, using regulated overexpression or conditional ablation in the context of chemical cutaneous carcinogenesis, we show that TTP represents a critical regulator of skin tumorigenesis. We provide evidence that TTP controls both tumor-associated inflammation and key oncogenic pathways in neoplastic epidermal cells. We identify Areg as a direct target of TTP in keratinocytes, and show that EGFR signaling potentially contributes to exacerbated tumor formation. Finally, single-cell RNA-Sequencing analysis indicates that ZFP36 is downregulated in human malignant keratinocytes. We conclude that TTP expression by epidermal cells plays a major role in the control of skin tumorigenesis.
Authors
Assiya Assabban, Ingrid Dubois-Vedrenne, Laurye Van Maele, Rosalba Salcedo, Brittany L. Snyder, Lecong Zhou, Abdulkader Azouz, Bérengère de Toeuf, Gaëlle Lapouge, Caroline La, Maxime Melchior, Muriel Nguyen, Séverine Thomas, Si Fan Wu, Wenqian Hu, Véronique Kruys, Cédric Blanpain, Giorgio Trinchieri, Cyril Gueydan, Perry J. Blackshear, Stanislas Goriely
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