Unchecked inflammation is a hallmark of inflammatory tissue injury in diseases such as acute respiratory distress syndrome (ARDS). Yet the mechanisms of inflammatory lung injury remain largely unknown. Here we showed that bacterial endotoxin lipopolysaccharide (LPS) and cecal ligation and puncture (CLP)-induced polymicrobial sepsis decreased the expression of transcription factor cAMP Response Element Binding (CREB) in lung endothelial cells. We demonstrated that endothelial CREB was crucial for VE-cadherin transcription and the formation of the normal restrictive endothelial adherens junctions. The inflammatory cytokine IL-1β reduced cAMP generation and CREB-mediated transcription of VE-cadherin. Furthermore, endothelial cell-specific deletion of CREB induced lung vascular injury whereas ectopic expression of CREB in the endothelium prevented the injury. We also observed that rolipram, which inhibits PDE4-mediated hydrolysis of cAMP, prevented endotoxemia-induced lung vascular injury since it preserved CREB-mediated VE-cadherin expression. These data demonstrate the fundamental role of endothelial cAMP-CREB axis in promoting lung vascular integrity and suppressing inflammatory injury. Therefore, strategies aimed at enhancing endothelial CREB-mediated VE-cadherin transcription are potentially useful in preventing sepsis-induced lung vascular injury in ARDS.
Shiqin Xiong, Zhigang Hong, Long Shuang Huang, Yoshikazu Tsukasaki, Saroj Nepal, Anke Di, Ming Zhong, Wei Wu, Zhiming Ye, XiaoPei Gao, Gadiparthi Rao, Dolly Mehta, Jalees Rehman, Asrar B. Malik
Ischemic acute kidney injury (AKI), a complication that frequently occurs in hospital settings, is often associated with hemodynamic compromise, sepsis, cardiac surgery or exposure to nephrotoxicants. Here, using a murine renal ischemia-reperfusion injury (IRI) model we show that intercalated cells (ICs) rapidly adopted a pro-inflammatory phenotype post-IRI. During the early phase of AKI, we demonstrate that either blocking the pro-inflammatory P2Y14 receptor located on the apical membrane of ICs, or ablation of the gene encoding the P2Y14 receptor in ICs: 1) inhibited IRI-induced chemokine expression increase in ICs; 2) reduced neutrophil and monocyte renal infiltration; 3) reduced the extent of kidney dysfunction; and 4) attenuated proximal tubule (PT) damage. These observations indicate that the P2Y14 receptor participates in the very first inflammatory steps associated with ischemic AKI. In addition, we show that the concentration of the P2Y14 receptor ligand, uridine diphosphate-glucose (UDP-Glc), was higher in urine samples from intensive care unit patients who developed AKI compared to patients without AKI. In particular, we observed a strong correlation between UDP-Glc concentration and the development of AKI in cardiac surgery patients. Our study identifies the UDP-Glc/P2Y14 receptor axis as a potential target for the prevention and/or attenuation of ischemic-AKI.
Maria Agustina Battistone, Alexandra C. Mendelsohn, Raul German Spallanzani, Andrew S. Allegretti, Rachel N. Liberman, Juliana Sesma, Sahir Kalim, Susan M. Wall, Joseph V. Bonventre, Eduardo R. Lazarowski, Dennis Brown, Sylvie Breton
Immune microenvironment plays a critical role in lung cancer control versus progression and metastasis. In this investigation, we explored the impact of tumor-infiltrating-lymphocyte subpopulations on lung cancer biology by studying in vitro co-cultures, in vivo mouse models and human lung cancer tissue. Lymphocyte conditioned media-(CM) induced epithelial-mesenchymal-transition (EMT), and migration in both primary human lung cancer cells and cell lines. Correspondingly, major accumulation of Th9 and Th17 cells was detected in human lung cancer tissue, and correlated with poor survival. Co-culturing lung cancer cells with Th9/Th17 cells or exposing them to the respective-CM induced-EMT in cancer cells and modulated the expression profile of genes implicated in EMT and metastasis. These features were reproduced by the signatory cytokines IL–9 and IL–17, with gene regulatory profiles evoked by these cytokines partly overlapping and partly complementary. Co-injection of Th9 and/or Th17 cells with tumor cells in wildtype, Rag1-/-, Il9r-/- and Il17ra-/- mice altered tumor growth and metastasis. Accordingly, inhibition of IL–9 or IL–17 cytokines by neutralizing antibodies decreased EMT and slowed lung cancer progression and metastasis. In conclusion, Th9 and Th17 lymphocytes induce lung cancer cell EMT, thereby promoting migration, and metastatic spreading and offering for novel therapeutic strategies.
Ylia Salazar, Xiang Zheng, David Brunn, Hartmann Raifer, Felix S.R. Picard, Yajuan Zhang, Hauke Winter, Stefan Günther, Andreas Weigert, Benno Weigmann, Laure Dumoutier, Jean-Christophe Renauld, Ari Waisman, Anja Schmall, Amanda Tufman, Ludger Fink, Bernhard Brüne, Tobias Bopp, Friedrich Grimminger, Werner Seeger, Soni Savai Pullamsetti, Magdalena Huber, Rajkumar Savai
Neutrophilic inflammation is central to disease pathogenesis, e.g. in chronic obstructive pulmonary disease, yet the mechanisms retaining neutrophils within tissues remain poorly understood. With emerging evidence that axon guidance factors can regulate myeloid recruitment and that neutrophils can regulate expression of a class 3 Semaphorin, SEMA3F, we investigated the role of SEMA3F in inflammatory cell retention within inflamed tissues. We observed that neutrophils upregulate SEMA3F in response to pro-inflammatory mediators and following recruitment to the inflamed lung. In both zebrafish tail injury and murine acute lung injury models of neutrophilic inflammation, overexpression of SEMA3F delayed inflammation resolution with slower neutrophil migratory speeds and retention of neutrophils within the tissues. Conversely, constitutive loss of sema3f accelerated egress of neutrophils from the tail injury site in fish, whilst neutrophil specific deletion of Sema3f in mice resulted in more rapid neutrophil transit through the airways, and significantly reduced time to resolution of the neutrophilic response. Study of filamentous- (F-) actin subsequently showed SEMA3F mediated retention is associated with F-actin disassembly. In conclusion, SEMA3F signaling actively regulates neutrophil retention within the injured tissues with consequences for neutrophil clearance and inflammation resolution.
Tracie Plant, Suttida Eamsamarng, Manuel A. Sanchez-Garcia, Leila Reyes, Stephen A. Renshaw, Patricia Coelho, Ananda S. Mirchandani, Jessie-May Morgan, Felix E. Ellett, Tyler Morrison, Duncan Humphries, Emily R. Watts, Fiona Murphy, Ximena L. Raffo-Iraolagoitia, Ailiang Zhang, Jenna L. Cash, Catherine Loynes, Philip M. Elks, Freek Van Eeden, Leo M. Carlin, Andrew J. W. Furley, Moira K. B. Whyte, Sarah R. Walmsley
Chronic inflammation is a pathologic feature of neurodegeneration and aging; however, the mechanism regulating this process is not understood. Melatonin, an endogenous free radical scavenger synthesized by neuronal mitochondria, decreases with aging and neurodegeneration. We proposed that insufficient melatonin levels impair mitochondrial homeostasis resulting in mitochondrial DNA (mtDNA) release, activation of cytosolic DNA mediated inflammatory response in neurons. We found increased mitochondrial oxidative stress and decreased mitochondrial membrane potential with higher mitochondrial DNA (mtDNA) release in brain and primary cerebro-cortical neurons of melatonin deficient aralkylamine N-acetyltransferase (AANAT) knockout mice. Cytosolic mtDNA activated the cGAS/STING/IRF3 pathway, stimulating inflammatory cytokine generation. We found that Huntington's disease mice increased mtDNA release, cGAS activation, and inflammation, all inhibited by exogenous melatonin. Thus, we demonstrated that cytosolic mtDNA activated the inflammatory response in aging and neurodegeneration, a process modulated by melatonin. Furthermore, our data suggest that AANAT knockout mice are a model of accelerated aging.
Abhishek Jauhari, Sergei V. Baranov, Yalikun Suofu, Jinho Kim, Tanisha Singh, Svitlana Yablonska, Fang Li, Xiaomin Wang, Patrick Oberly, M. Beth Minnigh, Samuel M. Poloyac, Diane L. Carlisle, Robert M. Friedlander
Kallikrein-related peptidase 6 (KLK6) is a secreted serine protease hypothesized to promote inflammation via cleavage of protease-activated receptors (PAR)1 and PAR2. KLK6 levels are elevated in multiple inflammatory and autoimmune conditions, but no definitive role in pathogenesis has been established. Here, we show that skin-targeted overexpression of KLK6 causes generalized, severe psoriasiform dermatitis with spontaneous development of debilitating psoriatic arthritis-like joint disease. The psoriatic skin and joint phenotypes are reversed by normalization of skin KLK6 levels and attenuated following genetic elimination of PAR1 but not PAR2. Conservation of this regulatory pathway was confirmed in human psoriasis using vorapaxar, an FDA-approved PAR1 antagonist, on explanted lesional skin from psoriasis patients. Beyond defining a critical role for KLK6-PAR1 signaling in promoting psoriasis, our results demonstrate that KLK6-PAR1-mediated inflammation in the skin alone is sufficient to drive inflammatory joint disease. Further, we identify PAR1 as a promising cytokine-independent target in therapy of psoriasis and psoriatic arthritis.
Allison C. Billi, Jessica E. Ludwig, Yi Fritz, Richard Rozic, William R. Swindell, Lam C. Tsoi, Dennis Gruszka, Shahla Abdollahi-Roodsaz, Xianying Xing, Doina Diaconu, Ranjitha Uppala, Maya I. Camhi, Philip A. Klenotic, Mrinal K. Sarkar, M. Elaine Husni, Jose U. Scher, Christine McDonald, J. Michelle Kahlenberg, Ronald J. Midura, Johann E. Gudjonsson, Nicole L. Ward
Understanding the circuits that promote an efficient resolution of inflammation is crucial to deciphering the molecular and cellular processes required to promote tissue repair. Macrophages play a central role in the regulation of inflammation, resolution, and repair/regeneration. Using a model of skeletal muscle injury and repair, herein we identified annexin A1 (AnxA1) as the extracellular trigger of macrophage skewing toward a pro-reparative phenotype. Brought into the injured tissue initially by migrated neutrophils, and then overexpressed in infiltrating macrophages, AnxA1 activated FPR2/ALX receptors and the downstream AMPK signaling cascade, leading to macrophage skewing, dampening of inflammation, and regeneration of muscle fibers. Mice lacking AnxA1 in all cells or only in myeloid cells displayed a defect in this reparative process. In vitro experiments recapitulated these properties, with AMPK-null macrophages lacking AnxA1-mediated polarization. Collectively, these data identified the AnxA1/FPR2/AMPK axis as an important pathway in skeletal muscle injury regeneration.
Simon McArthur, Gaëtan Juban, Thomas Gobbetti, Thibaut Desgeorges, Marine Theret, Julien Gondin, Juliana E. Toller-Kawahisa, Chris P. Reutelingsperger, Bénédicte Chazaud, Mauro Perretti, Rémi Mounier
Increased microvascular permeability to plasma proteins and neutrophil emigration are hallmarks of innate immunity and key features of numerous inflammatory disorders. Whilst neutrophils can promote microvascular leakage, the impact of vascular permeability on neutrophil trafficking is unknown. Here, through the application of confocal intravital microscopy, we reported 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 rTEM. Mechanistically, elevated vascular leakage promoted movement of interstitial chemokines into the blood stream, a response that supported abluminal-to-luminal neutrophil TEM. Through development of an in vivo cell labelling method we provided direct evidence for the systemic dissemination of rTEM neutrophils, showed them to exhibit an activated phenotype and capable of trafficking to the lungs where their presence was aligned with regions of vascular injury. Collectively, we demonstrated that increased microvascular leakage reverses the localisation of directional cues across venular walls, thus causing neutrophils engaged in diapedesis to re-enter 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.
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
Cystic fibrosis (CF) lung disease is characterized by an inflammatory response that can lead to terminal respiratory failure. The cystic fibrosis transmembrane regulator (CFTR) is mutated in CF and we hypothesized that dysfunctional CFTR in platelets, which are key participants in immune responses, is a central determinant of CF inflammation. We found that deletion of CFTR in platelets produced exaggerated acute lung inflammation and platelet activation after intratracheal LPS or Pseudomonas aeruginosa challenge. CFTR loss of function in mouse or human platelets resulted in agonist-induced hyperactivation and increased calcium entry into platelets. Inhibition of the transient receptor potential cation channel 6 (TRPC6) reduced platelet activation and calcium flux, and reduced lung injury in CF mice after intratracheal LPS or Pseudomonas aeruginosa challenge. CF subjects receiving CFTR modulator therapy showed partial restoration of CFTR function in platelets, which may be a convenient approach to monitoring biological responses to CFTR modulators. We conclude that CFTR dysfunction in platelets produces aberrant TRPC6-dependent platelet activation, which is a major driver of CF lung inflammation and impaired bacterial clearance. Platelets, and TRPC6, are what we believe to be novel therapeutic targets in the treatment of CF lung disease.
Guadalupe Ortiz-Munoz, Michelle A. Yu, Emma Lefrançais, Benat Mallavia, Colin Valet, Jennifer J. Tian, Serena Ranucci, Kristin M. Wang, Zhe Liu, Nicholas Kwaan, Diana Dawson, Mary Ellen Kleinhenz, Fadi T. Khasawneh, Peter M. Haggie, Alan S. Verkman, Mark R. Looney
While the Western-diet and dysbiosis are the most prominent environmental factors associated with inflammatory bowel diseases (IBDs), the corresponding host factors and cellular mechanisms remain poorly defined. Here we report that the TSC1-mTOR pathway in the gut epithelium represents a metabolic and innate immune checkpoint for intestinal dysfunction and inflammation. mTOR hyperactivation triggered by the Western-diet or Tsc1-ablation led to epithelium necroptosis, barrier disruption, and predisposition to DSS (dextran sulfate sodium)-induced colitis and inflammation-associated colon cancer. Mechanistically, our results uncovered a critical role for TSC1-mTOR in restraining the expression and activation of RIPK3 in the gut epithelium through Trim11-mediated ubiquitination and autophagy-dependent degradation. Notably, microbiota-depletion by antibiotics or gnotobiotics attenuated RIPK3 expression and activation, thereby alleviating epithelial necroptosis and colitis driven by mTOR hyperactivation. mTOR primarily impinged on RIPK3 to potentiate TNF- and microbial PAMP-induced necroptosis, and hyperactive mTOR and aberrant necroptosis were intertwined in human IBDs. Together, our data reveal a previously unsuspected link between the Western-diet, microbiota and necroptosis, and identify the mTOR-RIPK3-necroptosis axis as a driving force for intestinal inflammation and cancer.
Yadong Xie, Yifan Zhao, Lei Shi, Wei Li, Kun Chen, Min Li, Xia Chen, Haiwei Zhang, Tiantian Li, Matsuzawa-Ishimoto Yu, Xiaomin Yao, Dianhui Shao, Zunfu Ke, Jian Li, Yan Chen, Xiaoming Zhang, Jun Cui, Shuzhong Cui, Qibin Leng, Ken Cadwell, Xiaoxia Li, Hong Wei, Haibing Zhang, Huabin Li, Hui Xiao
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