A hallmark of HIV-1 infection is chronic inflammation, even in patients treated with antiretroviral therapy (ART). Chronic inflammation drives HIV-1 pathogenesis, leading to loss of CD4+ T cells and exhaustion of antiviral immunity. Therefore, strategies to safely reduce systematic inflammation are needed to halt disease progression and restore defective immune responses. Autophagy is a cellular mechanism for disposal of damaged organelles and elimination of intracellular pathogens. Autophagy is pivotal for energy homeostasis and plays critical roles in regulating immunity. However, how it regulates inflammation and antiviral T cell responses during HIV infection is unclear. Here, we demonstrate that autophagy is directly linked to IFN-I signaling, which is a key driver of immune activation and T cell exhaustion during chronic HIV infection. Impairment of autophagy leads to spontaneous IFN-I signaling, and autophagy induction reduces IFN-I signaling in monocytic cells. Importantly, in HIV-1–infected humanized mice, autophagy inducer rapamycin treatment significantly reduced persistent IFN-I–mediated inflammation and improved antiviral T cell responses. Cotreatment of rapamycin with ART led to significantly reduced viral rebound after ART withdrawal. Taken together, our data suggest that therapeutically targeting autophagy is a promising approach to treat persistent inflammation and improve immune control of HIV replication.
Wenli Mu, Valerie Rezek, Heather Martin, Mayra A. Carrillo, Shallu Tomer, Philip Hamid, Miguel A. Lizarraga, Tristan D. Tibbe, Otto O. Yang, Beth D. Jamieson, Scott G. Kitchen, Anjie Zhen
We determined whether gut microbiota-produced trimethylamine (TMA) is oxidized into trimethylamine N-oxide (TMAO) in non-liver tissues, whether TMAO promotes inflammation via trained immunity (TI) and made the following findings: Endoplasmic reticulum (ER) stress genes were co-upregulated with mitoCarta genes in chronic kidney diseases (CKD); TMAO upregulated 190 genes in human aortic endothelial cells (HAECs); TMAO synthesis enzyme flavin-containing monooxygenase 3 (FMO3) was expressed in human and mouse aortas,;4) TMAO trans-differentiated HAECs into innate immune cells; TMAO phosphorylated 12 kinases in cytosol via its receptor PERK and CREB, and integrated with PERK pathways; and PERK inhibitors suppressed TMAO-induced ICAM-1; TMAO upregulated 3 mitochondrial genes and downregulated inflammation inhibitor DARS2, induced mitoROS; and mitoTEMPO inhibited TMAO-induced ICAM-1; and -glucan priming followed by TMAO re-stimulation upregulated TNF-α by inducing metabolic reprogramming; and glycolysis inhibitor suppressed TMAO-induced ICAM-1. Our results have provided novel insights over TMAO roles in inducing EC activation and innate immune trans-differentiation, inducing metabolic reprogramming and TI for enhanced vascular inflammation and new therapeutic targets for treating cardiovascular diseases (CVD), CKD-promoted CVD, inflammations, transplantation, aging, and cancers.
Fatma Saaoud, Lu Liu, Keman Xu, Ramon Cueto, Ying Shao, Yifan Lu, Yu Sun, Nathaniel W. Snyder, Sheng Wu, Ling Yang, Yan Zhou, David L. Williams, Chuanfu Li, Laisel Martinez, Roberto I. Vazquez-Padron, Huaqing Zhao, Xiaohua Jiang, Hong Wang, Xiaofeng Yang
Acute and chronic intestinal inflammation is associated with epithelial damage, resulting in mucosal wounds in the forms of erosions and ulcers in the intestinal tract. Intestinal epithelial cells (IECs) and immune cells in the wound milieu secrete cytokines and lipid mediators to influence repair. Leukotriene B4 (LTB4), a lipid chemokine, binds to its receptor BLT1 and promotes migration of immune cells to sites of active inflammation, however a role for intestinal epithelial BLT1 during mucosal wound repair is not known. Here we report that BLT1 is expressed in IECs both in vitro and in vivo, where it functions as a receptor not only for LTB4 but also for another ligand Resolvin E1. Intestinal epithelial BLT1 expression is increased when epithelial cells are exposed to an inflammatory microenvironment. Using human and murine primary colonic epithelial cells, we reveal that LTB4-BLT1 axis promotes epithelial migration and proliferation leading to accelerated epithelial wound repair. Furthermore, in vivo intestinal wound repair experiments in BLT1-deficient mice and bone marrow chimeras demonstrate an important contribution of epithelial BLT1 during colonic mucosal wound repair. Taken together, our findings show a novel pro-repair in IEC mechanism mediated by BLT1 signaling.
Shusaku Hayashi, Chithra K. Muraleedharan, Makito Oku, Sunil Tomar, Simon P. Hogan, Miguel Quiros, Charles A. Parkos, Asma Nusrat
Identifying host factors that contribute to pneumonia incidence and severity are of utmost importance to guiding the development of more effective therapies. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a scavenger receptor known to promote vascular injury and inflammation, but it is unknown whether and how LOX-1 functions in the lung. Here, we provide evidence of substantial accumulation of LOX-1 in the lungs of ARDS patients and in mice with pneumonia. Unlike previously described injurious contributions of LOX-1, we found that LOX-1 is uniquely protective in the pulmonary airspaces, limiting proteinaceous edema and inflammation. We also identified alveolar macrophages and recruited neutrophils as two prominent sites of LOX-1 expression in the lungs, whereby macrophages are capable of further induction during pneumonia and neutrophils exhibit a rapid, but heterogenous elevation of LOX-1 in the infected lung. Blockade of LOX-1 led to dysregulated immune signaling in alveolar macrophages, marked by alterations in activation markers and a concomitant elevation of inflammatory gene networks. However, bone marrow chimeras also suggested a prominent role for neutrophils in LOX-1-mediated lung protection, further supported by LOX-1+ neutrophils exhibiting transcriptional changes consistent with reparative processes. Taken together, this work establishes LOX-1 as a tissue-protective factor in the lungs during pneumonia, possibly mediated by its influence on immune signaling in alveolar macrophages (AMs) and LOX-1+ airspace neutrophils.
Filiz T. Korkmaz, Anukul T. Shenoy, Elise Symer, Lillia A. Baird, Christine V. Odom, Emad Arafa, Ernest L. Dimbo, Elim Na, William Molina-Arocho, Matthew Brudner, Theodore J. Standiford, Jawahar L. Mehta, Tatsuya Sawamura, Matthew R. Jones, Joseph P. Mizgerd, Katrina T. Traber, Lee J. Quinton
Acute pancreatitis (AP) is a local and/or systemic inflammatory disease that starts with acinar cell injury and necrosis, which has no effective medical treatment and thus remains a life-threatening condition. Interleukin-37 (IL-37), a natural immunomodulator, has demonstrated an anti-inflammatory effect; however, the role of IL-37 in AP remains unknown. The serum IL-37 levels of 39 healthy controls and 94 AP patients were measured. Cholecystokinin was applied to induce pancreatic acinar cell injury in vitro. Classical experimental AP models, such as caerulein, L-arginine, and Taurocholic acid sodium salt were included in the in vivo study. A transgenic mouse model with the IL-37 gene and administration of recombinant IL-37 were used to further investigate the function of IL-37 in AP. Pancreas-specific GSDMD knockout mice were used to explore the protective mechanism of IL-37. Our results showed that serum IL-37 levels of human were negatively correlated with the severity of AP. Furthermore, transgenic IL-37 mice and supplementation with recombinant IL-37 could both protect against AP. Mechanistically, IL-37 was able to suppress pyroptosis of injured acinar cells, and specific depletion of GSDMD in the pancreas counteracted the protective effect of IL-37. Our study demonstrates that IL-37 protects against acinar cell pyroptosis in AP.
Nan Ma, Chenchen Yuan, Juanjuan Shi, Qingtian Zhu, Yang Liu, Xiaojie Ma, Baiqiang Li, Weijuan Gong, Jing Xue, Guotao Lu, Weiqin Li, Jieshou Li
Pancreatitis, the inflammatory disorder of the pancreas, has no specific therapy. Genetic, biochemical and animal model studies revealed that trypsin plays a central role in the onset and progression of pancreatitis. Here, we performed biochemical and preclinical mouse experiments to offer proof of concept that orally administered dabigatran etexilate can inhibit pancreatic trypsins and shows therapeutic efficacy in trypsin-dependent pancreatitis. We found that dabigatran competitively inhibited all human and mouse trypsin isoforms (Ki range 10-79 nM) and dabigatran plasma concentrations in mice given oral dabigatran etexilate well exceeded the Ki of trypsin inhibition. In the T7K24R trypsinogen mutant mouse model, a single oral gavage of dabigatran etexilate was effective against cerulein-induced progressive pancreatitis with a high degree of histological normalization. In contrast, spontaneous pancreatitis in T7D23A mice, which carry a more aggressive trypsinogen mutation, was not ameliorated by dabigatran etexilate, given either as daily gavages or by mixing it with solid chow. Taken together, our observations confirmed that benzamidine derivatives such as dabigatran are potent trypsin inhibitors and show therapeutic activity against trypsin-dependent pancreatitis in T7K24R mice. Lack of efficacy in T7D23A mice is likely related to the more severe pathology and insufficient drug concentrations in the pancreas.
Zsófia G. Pesei, Zsanett Jancsó, Alexandra Demcsák, Balázs Csaba Németh, Sandor Vajda, Miklós Sahin-Tóth
STING gain-of-function mutations cause STING-associated vasculopathy with onset in infancy (SAVI) in humans, a disease characterized by spontaneous lung inflammation and fibrosis. Mice with STING gain-of-function mutations (SAVI mice) develop αβ T cell–dependent lung disease and also lack lymph nodes. Although SAVI has been regarded as a type I interferonopathy, the relative contributions of the three interferon receptors are incompletely understood. Here, we show that STING gain of function led to upregulation of IFN-γ–induced chemokines in the lungs of SAVI mice and that deletion of the type II IFN receptor (IFNGR1), but not the type I IFN receptor (IFNAR1) or type III IFN receptor (IFNλR1), ameliorated lung disease and restored lymph node development in SAVI mice. Furthermore, deletion of IFNGR1, but not IFNAR1 or IFNλR1, corrected the ratio of effector to Tregs in SAVI mice and in mixed bone marrow chimeric mice. Finally, cultured SAVI mouse macrophages were hyperresponsive to IFN-γ, but not IFN-β, in terms of Cxcl9 upregulation and cell activation. These results demonstrate that IFNGR1 plays a major role in autoinflammation and immune dysregulation mediated by STING gain of function.
W. Alexander Stinson, Cathrine A. Miner, Fang R. Zhao, Annena Jane Lundgren, Subhajit Poddar, Jonathan J. Miner
Pseudomonas aeruginosa is one of the most common nosocomial infections worldwide, and frequently causes ventilator-associated acute pneumonia in immunocompromised patients. Abundant neutrophil extracellular traps (NETs) contribute to acute lung injury, thereby aggravating ventilator-induced lung damage. While pattern recognition receptors (PRRs) TLR4 and TLR5 are required for host defense against P. aeruginosa invasion, the PRR responsible for P. aeruginosa-induced NET formation, proinflammatory cytokine release, and acute lung injury remains unclear. We found that myeloid C-type lectin domain family 5 member A (CLEC5A) interacts with lipopolysaccharides of P. aeruginosa, and is responsible for P. aeruginosa-induced NET formation and lung inflammation. P. aeruginosa activates CLEC5A to induce caspase-1-dependent NET formation, but it neither causes gasdermin D (GSDMD) cleavage nor contributes to P. aeruginosa-induced neutrophil death. Blockade of CLEC5A attenuates P. aeruginosa-induced NETosis and lung injury, and simultaneous administration of anti-CLEC5A mAb with ciprofloxacin increases survival rate and decreases collagen deposition in the lungs of mice challenged with a lethal dose of P. aeruginosa. Thus, CLEC5A is a promising therapeutic target to reduce ventilator-associated lung injury and fibrosis in P. aeruginosa-induced pneumonia.
Pei-Shan Sung, Yu-Chun Peng, Shao-Ping Yang, Cheng-Hsun Chiu, Shie-Liang Hsieh
The blood-brain barrier is formed by capillary endothelial cells expressing Cx37, Cx40 and Cx43, and is joined by closely apposed astrocytes expressing Cx43 and Cx30. We investigated whether connexin-targeting peptides could limit barrier leakage triggered by LPS-induced systemic inflammation in mice. Intraperitoneal LPS increased endothelial and astrocytic Cx43 expression, elevated TNFα, IL1β, IFNγ and IL6 in plasma and IL6 in the brain, and induced barrier leakage recorded over 24h. Barrier leakage was largely prevented by global Cx43 knockdown and Cx43/Cx30 double-knockout in astrocytes, slightly diminished by endothelial Cx43 knockout and not protected by global Cx30 knockout. Intravenous administration of Gap27 or Tat-Gap19 just before LPS also prevented barrier leakage, and intravenous BAPTA-AM to chelate intracellular calcium was equally effective. Patch-clamp experiments demonstrated LPS-induced Cx43 hemichannel opening in endothelial cells, which was suppressed by Gap27, Gap19 and BAPTA. LPS additionally triggered astrogliosis that was prevented by intravenous Tat-Gap19 or BAPTA-AM. Cortically applied Tat-Gap19 or BAPTA-AM to primarily target astrocytes, also strongly diminished barrier leakage. In vivo dye uptake and in vitro patch-clamp showed Cx43 hemichannel opening in astrocytes that was induced by IL6 in a calcium-dependent manner. We conclude that targeting endothelial and astrocytic connexins is a powerful approach to limit barrier failure and astrogliosis.
Marijke De Bock, Maarten A.J. De Smet, Stijn Verwaerde, Hanane Tahiri, Steffi Schumacher, Valérie Van Haver, Katja Witschas, Christian Steinhäuser, Nathalie Rouach, Roosmarijn E. Vandenbroucke, Luc Leybaert
Dysregulation in neutrophil extracellular trap (NET) formation and degradation may play a role in the pathogenesis and severity of COVID-19; however, its role in the pediatric manifestations of this disease including multisystem inflammatory syndrome in children (MIS-C) and chilblain-like lesions (CLL), otherwise known as “COVID toes”, remains unclear. Studying multinational cohorts, we found that, in CLL, NETs were significantly increased in serum and skin. There was geographic variability in the prevalence of increased NETs in MIS-C, in association with disease severity. MIS-C and CLL serum samples displayed decreased NET degradation ability, in association with C1q and G-actin or anti-NET antibodies, respectively, but not with genetic variants of DNases. In adult COVID-19, persistent elevations in NETs post-disease diagnosis were detected but did not occur in asymptomatic infection. COVID-19-affected adults displayed significant prevalence of impaired NET degradation, in association with anti-DNase1L3, G-actin, and specific disease manifestations, but not with genetic variants of DNases. NETs were detected in many organs of adult patients who died from COVID-19 complications. Infection with the Omicron variant was associated with decreased levels of NETs when compared to other SARS-CoV-2 strains. These data support a role for NETs in the pathogenesis and severity of COVID-19 in pediatric and adult patients.
Carmelo Carmona-Rivera, Yu Zhang, Kerry Dobbs, Tovah E. Markowitz, Clifton L. Dalgard, Andrew J. Oler, Dillon R. Claybaugh, Deborah Draper, Meng Truong, Ottavia M. Delmonte, Francesco Licciardi, Ugo Ramenghi, Nicoletta Crescenzio, Luisa Imberti, Alessandra Sottini, Virginia Quaresima, Chiara Fiorini, Valentina Discepolo, Andrea Lo Vecchio, Alfredo Guarino, Luca Pierri, Andrea Catzola, Andrea Biondi, Paolo Bonfanti, Maria Cecilia Poli Harlowe, Yazmin Espinosa, Camila A. Astudillo, Emma Rey-Jurado, Cecilia Vial, Javiera De la Cruz, Ricardo Gonzalez, Cecilia Pinera, Jacqueline W. Mays, Ashley Ng, Andrew Platt, Beth A. Drolet, John Moon, Edward W. Cowen, Heather Kenney, Sarah E. Weber, Riccardo Castagnoli, Mary K. Magliocco, Michael Austin Stack, Gina A. Montealegre Sanchez, Karyl Barron, Danielle L. Fink, Douglas B. Kuhns, Stephen M. Hewitt, Lisa M. Arkin, Daniel S. Chertow, Helen C. Su, Luigi D. Notarangelo, Mariana J. Kaplan
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