Wen Zhang1,2, Lei Wang2, Xue-Hua Sun1,2, Xian Liu2, Yang Xiao2, Jie Zhang1,2, Ting Wang2,3, Hui Chen2, Yi-Qun Zhan2, Miao Yu2, Chang-Hui Ge4, Chang-Yan Li2, Guang-Ming Ren5, Rong-Hua Yin6, Xiao-Ming Yang7,8. 1. Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China. 2. State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 102206, China. 3. School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, Anhui Province, China. 4. Beijing Institute of Radiation Medicine, Beijing, 100850, China. 5. State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 102206, China. max19920503@163.com. 6. State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 102206, China. yrh1980110@126.com. 7. Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China. xiaomingyang@sina.com. 8. State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 102206, China. xiaomingyang@sina.com.
Abstract
BACKGROUND: Toll-like receptor 5 (TLR5)-mediated pathways play critical roles in regulating the hepatic immune response and show hepatoprotective effects in mouse models of hepatic diseases. However, the role of TLR5 in experimental models of liver regeneration has not been reported. This study aimed to investigate the role of TLR5 in partial hepatectomy (PHx)-induced liver regeneration. METHODS: We performed 2/3 PHx in wild-type (WT) mice, TLR5 knockout mice, or TLR5 agonist CBLB502 treated mice, as a model of liver regeneration. Bacterial flagellin content was measured with ELISA, and hepatic TLR5 expression was determined with quantitative PCR analyses and flow cytometry. To study the effects of TLR5 on hepatocyte proliferation, we analyzed bromodeoxyuridine (BrdU) incorporation and proliferating cell nuclear antigen (PCNA) expression with immunohistochemistry (IHC) staining. The effects of TLR5 during the priming phase of liver regeneration were examined with quantitative PCR analyses of immediate early gene mRNA levels, and with Western blotting analysis of hepatic NF-κB and STAT3 activation. Cytokine and growth factor production after PHx were detected with real-time PCR and cytometric bead array (CBA) assays. Oil Red O staining and hepatic lipid concentrations were analyzed to examine the effect of TLR5 on hepatic lipid accumulation after PHx. RESULTS: The bacterial flagellin content in the serum and liver increased, and the hepatic TLR5 expression was significantly up-regulated in WT mice after PHx. TLR5-deficient mice exhibited diminished numbers of BrdU- and PCNA-positive cells, suppressed immediate early gene expression, and decreased cytokine and growth factor production. Moreover, PHx-induced hepatic NF-κB and STAT3 activation was inhibited in Tlr5-/- mice, as compared with WT mice. Consistently, the administration of CBLB502 significantly promoted PHx-mediated hepatocyte proliferation, which was correlated with enhanced production of proinflammatory cytokines and the recruitment of macrophages and neutrophils in the liver. Furthermore, Tlr5-/- mice displayed significantly lower hepatic lipid concentrations and smaller Oil Red O positive areas than those in control mice after PHx. CONCLUSION: We reveal that TLR5 activation contributes to the initial events of liver regeneration after PHx. Our findings demonstrate that TLR5 signaling positively regulates liver regeneration and suggest the potential of TLR5 agonist to promote liver regeneration.
BACKGROUND:Toll-like receptor 5 (TLR5)-mediated pathways play critical roles in regulating the hepatic immune response and show hepatoprotective effects in mouse models of hepatic diseases. However, the role of TLR5 in experimental models of liver regeneration has not been reported. This study aimed to investigate the role of TLR5 in partial hepatectomy (PHx)-induced liver regeneration. METHODS: We performed 2/3 PHx in wild-type (WT) mice, TLR5 knockout mice, or TLR5 agonist CBLB502 treated mice, as a model of liver regeneration. Bacterial flagellin content was measured with ELISA, and hepatic TLR5 expression was determined with quantitative PCR analyses and flow cytometry. To study the effects of TLR5 on hepatocyte proliferation, we analyzed bromodeoxyuridine (BrdU) incorporation and proliferating cell nuclear antigen (PCNA) expression with immunohistochemistry (IHC) staining. The effects of TLR5 during the priming phase of liver regeneration were examined with quantitative PCR analyses of immediate early gene mRNA levels, and with Western blotting analysis of hepatic NF-κB and STAT3 activation. Cytokine and growth factor production after PHx were detected with real-time PCR and cytometric bead array (CBA) assays. Oil Red O staining and hepatic lipid concentrations were analyzed to examine the effect of TLR5 on hepatic lipid accumulation after PHx. RESULTS: The bacterial flagellin content in the serum and liver increased, and the hepatic TLR5 expression was significantly up-regulated in WT mice after PHx. TLR5-deficient mice exhibited diminished numbers of BrdU- and PCNA-positive cells, suppressed immediate early gene expression, and decreased cytokine and growth factor production. Moreover, PHx-induced hepatic NF-κB and STAT3 activation was inhibited in Tlr5-/- mice, as compared with WT mice. Consistently, the administration of CBLB502 significantly promoted PHx-mediated hepatocyte proliferation, which was correlated with enhanced production of proinflammatory cytokines and the recruitment of macrophages and neutrophils in the liver. Furthermore, Tlr5-/- mice displayed significantly lower hepatic lipid concentrations and smaller Oil Red O positive areas than those in control mice after PHx. CONCLUSION: We reveal that TLR5 activation contributes to the initial events of liver regeneration after PHx. Our findings demonstrate that TLR5 signaling positively regulates liver regeneration and suggest the potential of TLR5 agonist to promote liver regeneration.
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Authors: Laia Bertran; Rosa Jorba-Martin; Andrea Barrientos-Riosalido; Marta Portillo-Carrasquer; Carmen Aguilar; David Riesco; Salomé Martínez; Margarita Vives; Fàtima Sabench; Daniel Del Castillo; Cristóbal Richart; Teresa Auguet Journal: Int J Mol Sci Date: 2022-07-04 Impact factor: 6.208