Stefanie Ascher1,2, Eivor Wilms1, Giulia Pontarollo1, Henning Formes1, Franziska Bayer1, Maria Müller1, Frano Malinarich1, Alexandra Grill1,3, Markus Bosmann1,4, Mona Saffarzadeh1, Inês Brandão1,5, Kathrin Groß1, Klytaimnistra Kiouptsi1, Jens M Kittner6, Karl J Lackner7, Kerstin Jurk1, Christoph Reinhardt1,3. 1. From the Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University of Mainz (JGU), Germany (S.A., E.W., G.P., H.F., F.B., M.M., F.M., A.G., M.B., M.S., I.B., K.G., K.K., K.J., C.R.). 2. Institute for Pharmacy & Biochemistry, Johannes Gutenberg University of Mainz, Germany (S.A.). 3. German Center for Cardiovascular Research, Partner Site RheinMain, Mainz, Germany (A.G., C.R.). 4. Pulmonary Center, Department of Medicine, Boston University School of Medicine, MA (M.B.). 5. Centro de Apoio Tecnológico Agro Alimentar (CATAA), Zona Industrial de Castelo Branco, Portugal (I.B.). 6. I. Department of Medicine, University Medical Center of the Johannes Gutenberg University of Mainz, Germany (J.M.K.). 7. Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Mainz, Germany (K.J.L.).
Abstract
OBJECTIVE: Recruitment of neutrophils and formation of neutrophil extracellular traps (NETs) contribute to lethality in acute mesenteric infarction. To study the impact of the gut microbiota in acute mesenteric infarction, we used gnotobiotic mouse models to investigate whether gut commensals prime the reactivity of neutrophils towards formation of neutrophil extracellular traps (NETosis). Approach and Results: We applied a mesenteric ischemia-reperfusion (I/R) injury model to germ-free (GF) and colonized C57BL/6J mice. By intravital imaging, we quantified leukocyte adherence and NET formation in I/R-injured mesenteric venules. Colonization with gut microbiota or monocolonization with Escherichia coli augmented the adhesion of leukocytes, which was dependent on the TLR4 (Toll-like receptor-4)/TRIF (TIR-domain-containing adapter-inducing interferon-β) pathway. Although neutrophil accumulation was decreased in I/R-injured venules of GF mice, NETosis following I/R injury was significantly enhanced compared with conventionally raised mice or mice colonized with the minimal microbial consortium altered Schaedler flora. Also ex vivo, neutrophils from GF and antibiotic-treated mice showed increased LPS (lipopolysaccharide)-induced NETosis. Enhanced TLR4 signaling in GF neutrophils was due to elevated TLR4 expression and augmented IRF3 (interferon regulatory factor-3) phosphorylation. Likewise, neutrophils from antibiotic-treated conventionally raised mice had increased NET formation before and after ischemia. Increased NETosis in I/R injury was abolished in conventionally raised mice deficient in the TLR adaptor TRIF. In support of the desensitizing influence of enteric LPS, treatment of GF mice with LPS via drinking water diminished LPS-induced NETosis in vitro and in the mesenteric I/R injury model. CONCLUSIONS: Collectively, our results identified that the gut microbiota suppresses NETing neutrophil hyperreactivity in mesenteric I/R injury, while ensuring immunovigilance by enhancing neutrophil recruitment.
OBJECTIVE: Recruitment of neutrophils and formation of neutrophil extracellular traps (NETs) contribute to lethality in acute mesenteric infarction. To study the impact of the gut microbiota in acute mesenteric infarction, we used gnotobiotic mouse models to investigate whether gut commensals prime the reactivity of neutrophils towards formation of neutrophil extracellular traps (NETosis). Approach and Results: We applied a mesenteric ischemia-reperfusion (I/R) injury model to germ-free (GF) and colonized C57BL/6J mice. By intravital imaging, we quantified leukocyte adherence and NET formation in I/R-injured mesenteric venules. Colonization with gut microbiota or monocolonization with Escherichia coli augmented the adhesion of leukocytes, which was dependent on the TLR4 (Toll-like receptor-4)/TRIF (TIR-domain-containing adapter-inducing interferon-β) pathway. Although neutrophil accumulation was decreased in I/R-injured venules of GF mice, NETosis following I/R injury was significantly enhanced compared with conventionally raised mice or mice colonized with the minimal microbial consortium altered Schaedler flora. Also ex vivo, neutrophils from GF and antibiotic-treated mice showed increased LPS (lipopolysaccharide)-induced NETosis. Enhanced TLR4 signaling in GF neutrophils was due to elevated TLR4 expression and augmented IRF3 (interferon regulatory factor-3) phosphorylation. Likewise, neutrophils from antibiotic-treated conventionally raised mice had increased NET formation before and after ischemia. Increased NETosis in I/R injury was abolished in conventionally raised mice deficient in the TLR adaptor TRIF. In support of the desensitizing influence of enteric LPS, treatment of GF mice with LPS via drinking water diminished LPS-induced NETosis in vitro and in the mesenteric I/R injury model. CONCLUSIONS: Collectively, our results identified that the gut microbiota suppresses NETing neutrophil hyperreactivity in mesenteric I/R injury, while ensuring immunovigilance by enhancing neutrophil recruitment.
Authors: Jingjuan Hu; Fan Deng; Bingcheng Zhao; Zebin Lin; Qishun Sun; Xiao Yang; Mei Wu; Shida Qiu; Yu Chen; Zhengzheng Yan; Sidan Luo; Jin Zhao; Weifeng Liu; Cai Li; Ke Xuan Liu Journal: Microbiome Date: 2022-03-03 Impact factor: 14.650