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.
Cara E. Porsche, Jennifer B. DelProposto, Lynn Geletka, Robert O’Rourke, Carey N. Lumeng
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.
Yini Sun, Jerome C. Anyalebechi, He Sun, Tetsuya Yumoto, Ming Xue, Danya Liu, Zhe Liang, Craig M. Coopersmith, Mandy L. Ford
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
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
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.
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
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.
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
The molecular mechanisms that underlie the detrimental effects of particulate matter (PM) on skin barrier function are poorly understood. In this study, the effects of PM2.5 on filaggrin (FLG) and skin barrier function were investigated in vitro and in vivo. The levels of FLG degradation products including pyrrolidone carboxylic acid, urocanic acid (UCA), and cis/trans UCA were significantly decreased in skin tape stripping samples of study subjects when they moved from Denver, an area with low PM2.5, to Seoul, an area with high PM2.5 count. Experimentally, PM2.5 collected in Seoul inhibited FLG, loricrin, keratin-1, desmocollin-1, and corneodesmosin, but did not modulate involucrin or claudin-1 in keratinocyte cultures. Moreover, FLG protein expression was inhibited in human skin equivalents and murine skin treated with PM2.5. We demonstrate that this process was mediated by PM2.5-induced TNF-alpha and was aryl hydrocarbon receptor-dependent. PM2.5 exposure compromised skin barrier function, resulting in increased transepidermal water loss and enhanced the penetration of FITC-dextran in organotypic and mouse skin. PM2.5-induced TNF-alpha causes FLG deficiency in the skin and subsequently induces skin barrier dysfunction. Compromised skin barrier due to PM2.5 exposure may contribute to the development and the exacerbation of allergic diseases such as AD.
Byung Eui Kim, Jihyun Kim, Elena Goleva, Evgeny Berdyshev, Jinyoung Lee, Kathryn A. Vang, Un Ha Lee, SongYi Han, Susan Leung, Clifton F. Hall, Na-Rae Kim, Irina Bronova, Eu Jin Lee, Hye-Ran Yang, Donald Y.M. Leung, Kangmo Ahn
2'3'-cGAMP is known as a non-classical 2nd messenger and small immune modulator that possesses potent anti-tumor and antiviral activities through stimulating STING-mediated signaling pathway. However, its function in regulating type 2 immune responses remains unknown. We sought to determine a role of STING activation by 2'3'-cGAMP in type 2 inflammatory reactions in multiple mouse models of eosinophilic asthma. We discovered that 2'3'-cGAMP administration strongly attenuated type 2 lung immunopathology and airway hyperresponsiveness (AHR) induced by IL-33 and a fungal allergen, A. flavus. Mechanistically, upon the respiratory delivery, 2'3'-cGAMP was mainly internalized by alveolar macrophages, in which it activated the STING-IRF3-IFN-I signaling axis to induce the production of inhibitory factors containing IFNα, which blocked the IL-33-mediated activation of group 2 innate lymphoid cells (ILC2) in vivo. We further demonstrated that 2'3'-cGAMP directly suppressed the proliferation and function of both human and mouse ILC2 in vitro. Taken together, our findings suggest that STING activation by 2'3'-cGAMP in alveolar macrophages and ILC2 cells can negatively regulate type 2 immune responses, implying that the respiratory delivery of 2'3'-cGAMP might be further developed as an alternative strategy for treating type 2 immunopathologic diseases such as eosinophilic asthma.
Li She, Gema D. Barrera, Liping Yan, Hamad Hazzaa Alanazi, Edward G. Brooks, Peter H. Dube, Yilun Sun, Hong Zan, Daniel P. Chupp, Nu Zhang, Xin Zhang, Yong Liu, Xiao-Dong Li
Ginger is known to have anti-inflammatory and anti-oxidative effects, and has traditionally been used as an herbal supplement in the treatment of various chronic diseases. Here, we report anti-neutrophil properties of 6-gingerol, the most abundant bioactive compound of ginger root, in models of lupus and antiphospholipid syndrome (APS). Specifically, we demonstrate that 6-gingerol attenuates neutrophil extracellular trap (NET) release in response to lupus- and APS-relevant stimuli through a mechanism that at least partially dependent on inhibition of phosphodiesterases. At the same time, administration of 6-gingerol to mice reduces NET release in various models of lupus and APS, while also improving other disease-relevant endpoints such as autoantibody formation and large-vein thrombosis. In summary, this study is the first to demonstrate a protective role for ginger-derived compounds in the context of lupus, and importantly provides a potential mechanism for these effects via phosphodiesterase inhibition and attenuation of neutrophil hyperactivity.
Ramadan A. Ali, Alex A. Gandhi, Lipeng Dai, Julia K. Weiner, Shanea K. Estes, Srilakshmi Yalavarthi, Kelsey Gockman, Duxin Sun, Jason S. Knight
Aberrant activation of NLRP3 inflammasome has been implicated in a variety of human inflammatory diseases, however currently no pharmacological NLRP3 inhibitor has been approved in clinic. In this study, we showed that echinatin, the ingredient of the traditional herbal medicine licorice, effectively suppresses the activation of NLRP3 inflammasome in vitro and in vivo. Further investigation revealed that echinatin exerts its inhibitory effect on NLRP3 inflammasome by binding to heat-shock protein 90 (HSP90), inhibiting its ATPase activity, and disrupting the association between the cochaperone SGT1 and HSP90-NLRP3. Importantly, in vivo experiments demonstrated that administration of echinatin obviously inhibits NLRP3 inflammasome activation and ameliorates LPS-induced septic shock and DSS-induced colitis in mice. Moreover, echinatin exerted favorable pharmacological effects on liver inflammation and fibrosis in mouse model of non-alcoholic steatohepatitis (NASH). Collectively, our study identified echinatin as a novel inhibitor of NLRP3 inflammasome and may be developed as a potentially therapeutic approach for the treatment of NLRP3-driven diseases.
Guang Xu, Shubin Fu, Xiaoyan Zhan, Zhilei Wang, Ping Zhang, Wei Shi, Nan Qin, Yuanyuan Chen, Chunyu Wang, Ming Niu, Yuming Guo, Jia-bo Wang, Zhaofang Bai, Xiaohe Xiao
Immune dysfunction is an important factor driving mortality and adverse outcomes after trauma but remains poorly understood, especially at cellular level. To deconvolute trauma-induced immune response, we applied single-cell RNA sequencing to circulating and bone marrow mononuclear cells in injured mice and circulating mononuclear cells in trauma patients. In mice, the greatest changes in gene expression were seen in monocytes across both compartments. After systemic injury, the gene expression pattern of monocytes markedly deviated from steady state with corresponding changes in critical transcription factors (TFs), which can be traced back to myeloid progenitors. These changes were largely recapitulated in human single-cell analysis. We generalized the major changes in human CD14+ monocytes into six signatures, which further defined two trauma patient subtypes (SG1 vs. SG2) identified in the whole blood leukocyte transcriptome in the initial 12h after injury. Compared with SG2, SG1 patients exhibited delayed recovery, more severe organ dysfunction and a higher incidence of infection and non-infectious complications. The two patient subtypes were also recapitulated in burn and sepsis patients, revealing a shared pattern of immune response across critical illness. Our data will be broadly useful to further explore the immune response to inflammatory diseases and critical illness.
Tianmeng Chen, Matthew J. Delano, Kong Chen, Jason L. Sperry, Rami A. Namas, Ashley J. Lamparello, Meihong Deng, Julia Conroy, Lyle L. Moldawer, Philip A. Efron, Patricia A. Loughran, Christopher W. Seymour, Derek C. Angus, Yoram Vodovotz, Wei Chen, Timothy R. Billiar
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