Transient Receptor Potential Melastatin 2 Protects Mice against Polymicrobial Sepsis by Enhancing Bacterial Clearance

2014 ◽  
Vol 121 (2) ◽  
pp. 336-351 ◽  
Author(s):  
XiaoWei Qian ◽  
Tomohiro Numata ◽  
Kai Zhang ◽  
CaiXia Li ◽  
JinChao Hou ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Knockout Mice ◽  
Transient Receptor Potential ◽  
Cecal Ligation ◽  
Polymicrobial Sepsis ◽  
Bacterial Clearance ◽  
Cecal Ligation And Puncture ◽  
Bacterial Burden ◽  
Wild Type ◽  
Transient Receptor Potential Melastatin

Abstract Background: Recent studies suggest that the transient receptor potential melastatin 2 (TRPM2) channel plays an important role in inflammation and immune response. However, the role and mechanism of TRPM2 in polymicrobial sepsis remain unclear. Methods: The authors explored the effects of genetic disruption of TRPM2 on mortality (n = 15), bacterial clearance (n = 6), organ injury, and systemic inflammation during cecal ligation and puncture–induced sepsis. Electrophysiology, immunoblot, bacterial clearance experiment, and quantitative real-time polymerase chain reaction were used to explore the role and mechanism of TRPM2 in sepsis. Results: After cecal ligation and puncture, Trpm2-knockout mice had increased mortality compared with wild-type mice (73.3 vs. 40%, P = 0.0289). The increased mortality was associated with increased bacterial burden, organ injury, and systemic inflammation. TRPM2-mediated Ca2+ influx plays an important role in lipopolysaccharide or cecal ligation and puncture–induced heme oxygenase-1 (HO-1) expression in macrophage. HO-1 up-regulation decreased bacterial burden both in wild-type bone marrow–derived macrophages and in cecal ligation and puncture–induced septic wild-type mice. Disruption of TRPM2 decreased HO-1 expression and increased bacterial burden in bone marrow–derived macrophages. Pretreatment of Trpm2-knockout bone marrow–derived macrophages with HO-1 inducer markedly increased HO-1 expression and decreased bacterial burden. Pretreatment of Trpm2-knockout mice with HO-1 inducer reversed the susceptibility of Trpm2-knockout mice to sepsis by enhancing the bacterial clearance. In addition, septic patients with lower monocytic TRPM2 and HO-1 messenger RNA levels had a worse outcome compared with septic patients with normal monocytic TRPM2 and HO-1 messenger RNA levels. TRPM2 levels correlated with HO-1 levels in septic patients (r = 0.675, P = 0.001). Conclusion: The study data demonstrate a protective role of TRPM2 in controlling bacterial clearance during polymicrobial sepsis possibly by regulating HO-1 expression.

scholarly journals Disruption of the Transient Receptor Potential Vanilloid 1 Can Affect Survival, Bacterial Clearance, and Cytokine Gene Expression during Murine Sepsis

2011 ◽  
Vol 114 (5) ◽  
pp. 1190-1199 ◽  
Author(s):  
Virginia Guptill ◽  
Xizhong Cui ◽  
Alfia Khaibullina ◽  
Jason M. Keller ◽  
Nicholas Spornick ◽  
...  
Keyword(s):  
Mortality Risk ◽  
Transient Receptor Potential ◽  
Cecal Ligation ◽  
Receptor Potential ◽  
Hazard Ratio ◽  
Cytokine Gene Expression ◽  
Transient Receptor Potential Vanilloid ◽  
Bacterial Clearance ◽  
Cecal Ligation And Puncture ◽  
Transient Receptor

Background Previous studies suggest that the transient receptor potential vanilloid 1 (TRPV1) channel has a role in sepsis, but it is unclear whether its effect on survival and immune response is beneficial or harmful. Methods We studied the effects of genetic (Trpv1-knockout vs. wild-type [WT] mice) and pharmacologic disruption of TRPV1 with resiniferatoxin (an agonist) or capsazepine (an antagonist) on mortality, bacterial clearance, and cytokine expression during lipopolysaccharide or cecal ligation and puncture-induced sepsis. Results After cecal ligation and puncture, genetic disruption of TRPV1 in Trpv1-knockout versus WT mice was associated with increased mortality risk (hazard ratio, 2.17; 95% CI, 1.23-3.81; P = 0.01). Furthermore, pharmacologic disruption of TRPV1 with intrathecal resiniferatoxin, compared with vehicle, increased mortality risk (hazard ratio, 1.80; 95% CI, 1.05-3.2; P = 0.03) in WT, but not in Trpv1-knockout, mice. After lipopolysaccharide, neither genetic (Trpv1 knockout) nor pharmacologic disruption of TRPV1 with resiniferatoxin had significant effect on survival compared with respective controls. In contrast, after lipopolysaccharide, pharmacologic disruption of TRPV1 with capsazepine, compared with vehicle, increased mortality risk (hazard ratio, 1.92; 95% CI, 1.02-3.61; P = 0.04) in WT animals. Furthermore, after cecal ligation and puncture, increased mortality in resiniferatoxin-treated WT animals was associated with higher blood bacterial count (P = 0.0004) and higher nitrate/nitrite concentrations and down-regulation of tumor necrosis factor α expression (P = 0.004) compared with controls. Conclusions Genetic or pharmacologic disruption of TRPV1 can affect mortality, blood bacteria clearance, and cytokine response in sepsis in patterns that may vary according to the sepsis-inducing event and the method of TRPV1 disruption.

Differential effect of imipenem treatment on injury caused by cecal ligation and puncture in wild-type and NK cell-deficient β2-microgloblin knockout mice

2006 ◽  
Vol 290 (2) ◽  
pp. G277-G284 ◽  
Author(s):  
Victor T. Enoh ◽  
Cheng Y. Lin ◽  
Tushar K. Varma ◽  
Edward R. Sherwood
Keyword(s):  
Metabolic Acidosis ◽  
Knockout Mice ◽  
Nk Cell ◽  
Plasma Concentrations ◽  
Cecal Ligation ◽  
Systemic Infection ◽  
Cecal Ligation And Puncture ◽  
Wild Type ◽  
Term Survival ◽  
The Impact

Our previous studies showed that β2-microglobulin knockout mice treated with anti-asialoGM1 (β2MKO/αAsGM1 mice) are resistant to injury caused by cecal ligation and puncture (CLP). However, CLP-induced injury is complex. Potential mechanisms of injury include systemic infection, cecal ischemia, and translocation of bacterial toxins such as endotoxin and superantigens. Currently, it is unclear which of these mechanisms of injury contributes to mortality in wild-type mice and whether β2MKO/αAsGM1 mice are resistant to any particular mechanisms of injury. In the present study, we hypothesized that systemic infection is the major cause of injury after CLP in wild-type mice and that β2MKO/αAsGM1 mice are resistant to infection-induced injury. To test this hypothesis, wild-type and β2MKO/αAsGM1 mice were treated with the broad-spectrum antibiotic imipenem immediately after CLP to decrease the impact of systemic infection in our model. Treatment of wild-type and β2MKO/αAsGM1 mice with imipenem decreased bacterial counts by at least two orders of magnitude. However, all wild-type mice, whether treated with saline or imipenem, died by 42 h after CLP and had significant hypothermia, metabolic acidosis, and high plasma concentrations of the cytokines interleukin-6, macrophage inflammatory protein-2, and keratinocyte-derived chemokine. β2MKO/αAsGM1 mice showed 40% long-term survival, which was increased to 90% by imipenem treatment. β2MKO/αAsGM1 mice had less hypothermia, decreased metabolic acidosis, and lower cytokine concentrations at 18 h after CLP compared with wild-type mice. These results suggest that infection is not the major cause of mortality for wild-type mice in our model of CLP. Other mechanisms of injury such as cecal ischemia or translocation of microbial toxins may be more important. β2MKO/αAsGM1 mice appear resistant to these early, non-infection-related causes of CLP-induced injury but showed delayed mortality associated with bacterial dissemination, which was ablated by treatment with imipenem.

scholarly journals Toll-Like Receptors 2 and 4 Contribute to Sepsis-Induced Depletion of Spleen Dendritic Cells

2009 ◽  
Vol 77 (12) ◽  
pp. 5651-5658 ◽  
Author(s):  
Frédéric Pène ◽  
Emilie Courtine ◽  
Fatah Ouaaz ◽  
Benjamin Zuber ◽  
Bertrand Sauneuf ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Knockout Mice ◽  
Cecal Ligation ◽  
Polymicrobial Sepsis ◽  
Interleukin 12 ◽  
Maturation Process ◽  
Wild Type ◽  
Cpg Dna ◽  
Functional Features ◽  
Secondary Lymphoid Organs

ABSTRACT Depletion of dendritic cells (DC) in secondary lymphoid organs is a hallmark of sepsis-induced immune dysfunction. In this setting, we investigated if Toll-like receptor (TLR)-dependent signaling might modulate the maturation process and the survival of DC. Using a model of sublethal polymicrobial sepsis induced by cecal ligation and puncture, we investigated the quantitative and functional features of spleen DC in wild-type, TLR2−/−, TLR4−/−, and TLR2−/− TLR4−/− mice. By 24 h, a decrease in the relative percentage of CD11chigh spleen DC occurred in wild-type mice but was prevented in TLR2−/−, TLR4−/−, and TLR2−/− TLR4−/− mice. In wild-type mice, sepsis dramatically affected both CD11c+ CD8α+ and CD11c+ CD8α− subsets. In all three types of knockout mice studied, the CD11c+ CD8α+ subset followed a depletion pattern similar to that for wild-type mice. In contrast, the loss of CD11c+ CD8α− cells was attenuated in TLR2−/− and TLR4−/− mice and completely prevented in TLR2−/− TLR4−/− mice. Accordingly, apoptosis of spleen DC was increased in septic wild-type mice and inhibited in knockout mice. In addition we characterized the functional features of spleen DC obtained from septic mice. As shown by increased expression of major histocompatibility complex class II and CD86, polymicrobial sepsis induced maturation of DC, with subsequent increased capacity to prime T lymphocytes, similarly in wild-type and knockout mice. In response to CpG DNA stimulation, production of interleukin-12 was equally impaired in DC obtained from wild-type and knockout septic mice. In conclusion, although dispensable for the DC maturation process, TLR2 and TLR4 are involved in the mechanisms leading to depletion of spleen DC following polymicrobial sepsis.

scholarly journals Transient receptor potential melastatin 2–mediated heme oxygenase-1 has a role for bacterial clearance by regulating autophagy in peritoneal macrophages during polymicrobial sepsis

2019 ◽  
Vol 25 (8) ◽  
pp. 530-538
Author(s):  
XiaoWei Qian ◽  
Hao Cheng ◽  
XinZhong Chen
Keyword(s):  
Heme Oxygenase ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Peritoneal Macrophages ◽  
Polymicrobial Sepsis ◽  
Heme Oxygenase 1 ◽  
Bacterial Clearance ◽  
Transient Receptor Potential Melastatin ◽  
Caecal Ligation And Puncture ◽  
Caecal Ligation

Our previous study indicated an important protective role of transient receptor potential melastatin 2 (TRPM2) in controlling bacterial clearance in macrophages during polymicrobial sepsis by regulating heme oxygenase-1. Autophagy is necessary for macrophages to kill invasive bacteria. In the present study, TRPM2 knockout (KO) mice show decreased heme oxygenase-1 and autophagy in peritoneal macrophages after caecal ligation and puncture surgery. Caecal ligation and puncture-induced autophagy in peritoneal macrophages is dependent on heme oxygenase-1. TRPM2 KO mice treated with heme oxygenase-1 inducer before caecal ligation and puncture significantly increase autophagy of peritoneal macrophages, bacterial clearance rate and survival rate. In addition, TRPM2 KO mice treated with heme oxygenase-1 inducer before caecal ligation and puncture significantly attenuate organ injury and systemic inflammation. These improvements are reversed by autophagy inhibitor. Therefore, our findings suggest that TRPM2-mediated heme oxygenase-1 has a role for bacterial clearance possibly by regulating autophagy in peritoneal macrophages during polymicrobial sepsis.

Cardiovascular dysfunction caused by cecal ligation and puncture is attenuated in CD8 knockout mice treated with anti-asialoGM1

2005 ◽  
Vol 289 (2) ◽  
pp. R478-R485 ◽  
Author(s):  
Weike Tao ◽  
Victor T. Enoh ◽  
Cheng Y. Lin ◽  
William E. Johnston ◽  
Peng Li ◽  
...  
Keyword(s):  
Metabolic Acidosis ◽  
Arterial Pressure ◽  
Systemic Vascular Resistance ◽  
Knockout Mice ◽  
Myocardial Function ◽  
Cecal Ligation ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Cecal Ligation And Puncture ◽  
Wild Type

The present study was designed to assess hemodynamics and myocardial function at 18 h after injury caused by cecal ligation and puncture (CLP) in CD8-knockout mice treated with anti-asialoGM1 (CD8KO/αAsGM1 mice). Arterial pressure was measured by carotid artery cannulation, and left ventricular pressure-volume measurements were obtained by use of a 1.4-Fr conductance catheter. Blood acid-base balance and indexes of hepatic, renal, and pulmonary injury were also measured. CD8KO/αAsGM1 mice exhibited higher mean arterial pressure and increased systemic vascular resistance compared with wild-type mice. Cardiac output was significantly decreased in wild-type, but not CD8KO/αAsGM1, mice compared with sham controls. Myocardial function was better preserved in CD8KO/αAsGM1 mice as indicated by less impairment of left ventricular pressure development over time, time varying maximum elastance, end-systolic pressure-volume relationship, and preload recruitable stroke work. The impairment in myocardial function was associated with induction of proinflammatory cytokine mRNAs in the hearts of wild-type mice. The hemodynamic derangements in wild-type mice were coupled with significant metabolic acidosis and elevated serum creatinine levels. Overall, this study shows that cardiovascular collapse and shock characterized by hypotension, myocardial depression, low systemic vascular resistance, and metabolic acidosis occurs after CLP in wild-type mice but is attenuated in CD8KO/αAsGM1 mice. These observations likely explain, in part, the previously observed survival advantage of CD8KO/αAsGM1 mice following CLP.

scholarly journals Blockade of CD137 Signaling Counteracts Polymicrobial Sepsis Induced by Cecal Ligation and Puncture

2009 ◽  
Vol 77 (9) ◽  
pp. 3932-3938 ◽  
Author(s):  
Quang-Tam Nguyen ◽  
Seong-A Ju ◽  
Sang-Min Park ◽  
Sang-Chul Lee ◽  
Hideo Yagita ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Cecal Ligation ◽  
Polymicrobial Sepsis ◽  
Infection Model ◽  
Bacterial Clearance ◽  
Cecal Ligation And Puncture ◽  
Gram Positive ◽  
Necrosis Factor Alpha ◽  
Necrosis Factor

ABSTRACTSepsis, a leading cause of death worldwide, involves proinflammatory responses and inefficient bacterial clearance. Previously, we have shown that CD137 (4-1BB), a member of the tumor necrosis factor receptor superfamily, plays critical roles in eradicating infectiveListeria monocytogenes, a gram-positive bacterium, and that stimulation of CD137 protects mice from sepsis-induced death. In this study, we unexpectedly found that CD137 activation aggravated polymicrobial sepsis due to mixed gram-positive and gram-negative bacterial infection induced by cecal ligation and puncture (CLP). CD137-deficient (CD137−/−) mice showed significantly lower mortality than CD137-sufficient (CD137+/+) mice in the CLP model. Administration of an agonistic anti-CD137 monoclonal antibody (MAb) to CD137+/+mice decreased their survival in this infection model, while administration of a blocking anti-CD137 ligand MAb (TKS-1) to such mice increased their survival. CD137−/−mice and TKS-1-treated CD137+/+mice had lower levels of chemokines/proinflammatory cytokines (monocyte chemoattractant protein 1, interleukin-6 [IL-6], tumor necrosis factor alpha, IL-12) and an anti-inflammatory cytokine (IL-10), exhibited improved bacterial clearance in the peritoneum, liver, and blood, and had greater numbers of infiltrated peritoneal neutrophils and macrophages in the CLP model than control mice. Our data suggest that CD137 activation aggravates polymicrobial sepsis induced by CLP.

P717Glucagon-like peptide 1 (GLP-1) improves endothelial dysfunction and vascular inflammation in polymicrobial sepsis induced by cecal ligation and puncture (CLP)

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
S Steven ◽  
J Helmstaedter ◽  
F Pawelke ◽  
K Filippou ◽  
K Frenies ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Clinical Trials ◽  
Endothelial Dysfunction ◽  
Knockout Mice ◽  
Vascular Inflammation ◽  
Cecal Ligation ◽  
Cecal Ligation And Puncture ◽  
Glucose Levels ◽  
Dpp4 Inhibitor ◽  
Cardioprotective Effects

Abstract Objective Sepsis causes severe hypotension, accompanied by high mortality in the setting of septic shock. LEADER, SUSTAIN-6 and other clinical trials revealed cardioprotective and anti-inflammatory properties of GLP-1 analogs like Liraglutide (Lira). We already demonstrated improved survival by amelioration of disseminated intravasal coagulation (DIC) in lipopolysaccharide (LPS)-induced endotoxemia by inhibition of the GLP-1 degrading enzyme dipeptidylpeptidase-4 (DPP-4). With the present study we aim to investigate the mechanism of protective effects of the GLP-1 analog Lira and the DPP4 inhibitor Linagliptin (Lina) in the clinically relevant sepsis model cecal ligation and puncture (CLP). Methods C57/BL6j and endothelial cell-specific GLP-1 receptor knockout mice (Cdh5crexGLP-1rfl/flmice) were used and sepsis was induced by cecal ligation and puncture (CLP). DPP4 inhibitor (Lina, 5mg/kg/d; 3 days) and GLP-1 analog (Lira, 200μg/kg/d; 3 days) were applied subcutaneously. Aortic vascular function was tested by isometric tension recording. Aorta and heart tissue was used for Western blotting, dot blot and qRT-PCR. Endogenous GLP-1 (7–36 and 9–36) and insulin was determined by ELISA. Blood samples were collected for examination of cell count, oxidative stress and glucose levels. Results Body temperature was increased by CLP and normalized by Lina and Lira. Sham- and Lira- but not Lina-treated septic mice showed low blood glucose levels compared to healthy controls. Acetylcholine-induced (endothelium-dependent) vascular relaxation in aorta was impaired by CLP. This was accompanied by vascular inflammation and elevation of IL-6, iNOS, ICAM-1, and TNF-alpha mRNA levels in aortic tissue. Vascular, cardiac and whole blood oxidative stress were increased by CLP. Furthermore, we detected higher levels of IL-6, 3-nitrotyrosine (3-NT) and 4-hydroxynonenal (4-NHE) in plasma of CLP animals. Lina and Lira reduced oxidative stress and vascular inflammation, which was accompanied by improved endothelial function. In addition, CLP treatment in endothelial specific knockout mice of the GLP-1r strongly induced mortality compared to WT mice, with the effect being strongest in the Lira-treated group. Conclusion The present study demonstrates that Lina (DPP4 inhibitor) and the GLP-1 analog Lira ameliorate sepsis-induced endothelial dysfunction by reduction of vascular inflammation and oxidative stress. Clinical trials like LEADER and SUSTAIN-6 proved that GLP-1 analogs like Lira have cardioprotective effects in T2DM patients. The present study, performed in a clinically relevant model of polymicrobial sepsis, reveals that the known cardioprotective effects of GLP-1 might be translated to other diseases which affect the cardiovascular system like sepsis, underlining the potent anti-inflammatory effects of GLP-1 analogs.

scholarly journals Transient Receptor Potential Melastatin 2 Enhances Vascular Reactivity During Development of Atherosclerosis in Mice

2021 ◽  
Vol 34 (1) ◽  
pp. 121-122
Author(s):  
Yi-quan Dai ◽  
Xiao-xiao Yan ◽  
Yi-chen Lin ◽  
Hong-yu Chen ◽  
Xiao-ru Liu
Keyword(s):  
Knockout Mice ◽  
Vascular Reactivity ◽  
Transient Receptor Potential ◽  
Gene Knockout ◽  
Receptor Potential ◽  
Blood Lipid ◽  
Normal Diet ◽  
Protein Levels ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Abstract Background To investigate the function of transient receptor potential melastatin 2 (TRPM2) in vascular reactivity induced by 5-hydroxytryptamine (5-HT) in the aorta during development of atherosclerosis in mice. Methods Forty mice were randomly divided into 4 groups: C57BL/6J on normal diet (C57 + ND), C57BL/6J on high-fat diet (C57 + HFD), apolipoprotein E gene knockout mice (ApoE−/−) on ND (ApoE−/− + ND), and ApoE−/− on HFD (ApoE−/− + HFD). They were fed with a ND or HFD for 16 weeks. Aortic TRPM2 expression and isometric contractions were analyzed. Results In the ApoE−/− + HFD group, body weight, blood glucose, and blood lipid concentrations were increased, and aortic plaques were developed. Compared with the other 3 groups, aortic TRPM2 mRNA and protein levels were significantly increased in the ApoE−/− + HFD group (P < 0.01). Aortic reactivity to 5-HT was enhanced in ApoE−/− + HFD mice with lower EC50 values. The enhanced reactivity to 5-HT was significantly inhibited by TRPM2 inhibitors, N-p-amylcinnamoyl anthranilic acid (1 µmol/l) and 2-aminoethyl diphenylborinate (10 µmol/l). Conclusions Aortic TRPM2 expression is upregulated in ApoE knockout mice fed with a HFD. Upregulation of TRPM2 enhances 5-HT vascular reactivity during development of atherosclerosis.

scholarly journals Bone Marrow Mesenchymal Stromal Cells on Silk Fibroin Scaffolds to Attenuate Polymicrobial Sepsis Induced by Cecal Ligation and Puncture

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1433
Author(s):  
Ok-Hyeon Kim ◽  
Jun-Hyung Park ◽  
Jong-In Son ◽  
Ok-Ja Yoon ◽  
Hyun-Jung Lee
Keyword(s):  
Bone Marrow ◽  
Cecal Ligation ◽  
Biological Properties ◽  
Pge2 Production ◽  
Polymicrobial Sepsis ◽  
Control Surface ◽  
Related Factors ◽  
Cox 2 ◽  
Anti Inflammatory

Suitable scaffolds with appropriate mechanical and biological properties can improve mesenchymal stromal cell (MSC) therapy. Because silk fibroins (SFs) are biocompatible materials, they were electrospun and applied as scaffolds for MSC therapy. Consequently, interferon (IFN)-primed human bone marrow MSCs on SF nanofibers were administered into a polymicrobial sepsis murine model. The IL-6 level gradually decreased from 40 ng/mL at 6 h after sepsis to 35 ng/mL at 24 h after sepsis. The IL-6 level was significantly low as 5 ng/mL in primed MSCs on SF nanofibers, and 15 ng/mL in primed MSCs on the control surface. In contrast to the acute response, inflammation-related factors, including HO-1 and COX-2 in chronic liver tissue, were effectively inhibited by MSCs on both SF nanofibers and the control surface at the 5-day mark after sepsis. An in vitro study indicated that the anti-inflammatory function of MSCs on SF nanofibers was mediated through enhanced COX-2-PGE2 production, as indomethacin completely abrogated PGE2 production and decreased the survival rate of septic mice. Thus, SF nanofiber scaffolds potentiated the anti-inflammatory and immunomodulatory functions of MSCs, and were beneficial as a culture platform for the cell therapy of inflammatory disorders.

scholarly journals IL-17F depletion accelerates chitosan conduit guided peripheral nerve regeneration

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Feixiang Chen ◽  
Weihuang Liu ◽  
Qiang Zhang ◽  
Ping Wu ◽  
Ao Xiao ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Knockout Mice ◽  
Inflammatory Markers ◽  
Nerve Repair ◽  
Peripheral Nerve Regeneration ◽  
Wild Type ◽  
Anti Inflammatory

AbstractPeripheral nerve injury is a serious health problem and repairing long nerve deficits remains a clinical challenge nowadays. Nerve guidance conduit (NGC) serves as the most promising alternative therapy strategy to autografts but its repairing efficiency needs improvement. In this study, we investigated whether modulating the immune microenvironment by Interleukin-17F (IL-17F) could promote NGC mediated peripheral nerve repair. Chitosan conduits were used to bridge sciatic nerve defect in IL-17F knockout mice and wild-type mice with autografts as controls. Our data revealed that IL-17F knockout mice had improved functional recovery and axonal regeneration of sciatic nerve bridged by chitosan conduits comparing to the wild-type mice. Notably, IL-17F knockout mice had enhanced anti-inflammatory macrophages in the NGC repairing microenvironment. In vitro data revealed that IL-17F knockout peritoneal and bone marrow derived macrophages had increased anti-inflammatory markers after treatment with the extracts from chitosan conduits, while higher pro-inflammatory markers were detected in the Raw264.7 macrophage cell line, wild-type peritoneal and bone marrow derived macrophages after the same treatment. The biased anti-inflammatory phenotype of macrophages by IL-17F knockout probably contributed to the improved chitosan conduit guided sciatic nerve regeneration. Additionally, IL-17F could enhance pro-inflammatory factors production in Raw264.7 cells and wild-type peritoneal macrophages. Altogether, IL-17F may partially mediate chitosan conduit induced pro-inflammatory polarization of macrophages during nerve repair. These results not only revealed a role of IL-17F in macrophage function, but also provided a unique and promising target, IL-17F, to modulate the microenvironment and enhance the peripheral nerve regeneration.

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