TY - JOUR
T1 - Macrophage heme oxygenase-1-SIRT1-p53 axis regulates sterile inflammation in liver ischemia-reperfusion injury
AU - Nakamura, Kojiro
AU - Zhang, Min
AU - Kageyama, Shoichi
AU - Ke, Bibo
AU - Fujii, Takehiro
AU - Sosa, Rebecca A.
AU - Reed, Elaine F.
AU - Datta, Nakul
AU - Zarrinpar, Ali
AU - Busuttil, Ronald W.
AU - Araujo, Jesus A.
AU - Kupiec-Weglinski, Jerzy W.
N1 - Publisher Copyright:
© 2017 European Association for the Study of the Liver
PY - 2017/12
Y1 - 2017/12
N2 - Background & Aims Hepatic ischemia-reperfusion injury (IRI), characterized by exogenous antigen-independent local inflammation and hepatocellular death, represents a risk factor for acute and chronic rejection in liver transplantation. We aimed to investigate the molecular communication involved in the mechanism of liver IRI. Methods We analyzed human liver transplants, primary murine macrophage cell cultures and IR-stressed livers in myeloid-specific heme oxygenase-1 (HO-1) gene mutant mice, for anti-inflammatory and cytoprotective functions of macrophage-specific HO-1/SIRT1 (sirtuin 1)/p53 (tumor suppressor protein) signaling. Results Decreased HO-1 expression in human post-reperfusion liver transplant biopsies correlated with a deterioration in hepatocellular function (serum ALT; p <0.05) and inferior patient survival (p <0.05). In the low HO-1 liver transplant biopsy group, SIRT1/Arf (alternative reading frame)/p53/MDM2 (murine double minute 2) expression levels decreased (p <0.05) while cleaved caspase 3 and frequency of TUNEL + cells simultaneously increased (p <0.05). Immunofluorescence showed macrophages were the principal source of HO-1 in human and mouse IR-stressed livers. In vitro macrophage cultures revealed that HO-1 induction positively regulated SIRT1 signaling, whereas SIRT1-induced Arf inhibited ubiquitinating activity of MDM2 against p53, which in turn attenuated macrophage activation. In a murine model of hepatic warm IRI, myeloid-specific HO-1 deletion lacked SIRT1/p53, exacerbated liver inflammation and IR-hepatocellular death, whereas adjunctive SIRT1 activation restored p53 signaling and rescued livers from IR-damage. Conclusion This bench-to-bedside study identifies a new class of macrophages activated via the HO-1–SIRT1–p53 signaling axis in the mechanism of hepatic sterile inflammation. This mechanism could be a target for novel therapeutic strategies in liver transplant recipients. Lay summary Post-transplant low macrophage HO-1 expression in human liver transplants correlates with reduced hepatocellular function and survival. HO-1 regulates macrophage activation via the SIRT1–p53 signaling network and regulates hepatocellular death in liver ischemia-reperfusion injury. Thus targeting this pathway in liver transplant recipients could be of therapeutic benefit.
AB - Background & Aims Hepatic ischemia-reperfusion injury (IRI), characterized by exogenous antigen-independent local inflammation and hepatocellular death, represents a risk factor for acute and chronic rejection in liver transplantation. We aimed to investigate the molecular communication involved in the mechanism of liver IRI. Methods We analyzed human liver transplants, primary murine macrophage cell cultures and IR-stressed livers in myeloid-specific heme oxygenase-1 (HO-1) gene mutant mice, for anti-inflammatory and cytoprotective functions of macrophage-specific HO-1/SIRT1 (sirtuin 1)/p53 (tumor suppressor protein) signaling. Results Decreased HO-1 expression in human post-reperfusion liver transplant biopsies correlated with a deterioration in hepatocellular function (serum ALT; p <0.05) and inferior patient survival (p <0.05). In the low HO-1 liver transplant biopsy group, SIRT1/Arf (alternative reading frame)/p53/MDM2 (murine double minute 2) expression levels decreased (p <0.05) while cleaved caspase 3 and frequency of TUNEL + cells simultaneously increased (p <0.05). Immunofluorescence showed macrophages were the principal source of HO-1 in human and mouse IR-stressed livers. In vitro macrophage cultures revealed that HO-1 induction positively regulated SIRT1 signaling, whereas SIRT1-induced Arf inhibited ubiquitinating activity of MDM2 against p53, which in turn attenuated macrophage activation. In a murine model of hepatic warm IRI, myeloid-specific HO-1 deletion lacked SIRT1/p53, exacerbated liver inflammation and IR-hepatocellular death, whereas adjunctive SIRT1 activation restored p53 signaling and rescued livers from IR-damage. Conclusion This bench-to-bedside study identifies a new class of macrophages activated via the HO-1–SIRT1–p53 signaling axis in the mechanism of hepatic sterile inflammation. This mechanism could be a target for novel therapeutic strategies in liver transplant recipients. Lay summary Post-transplant low macrophage HO-1 expression in human liver transplants correlates with reduced hepatocellular function and survival. HO-1 regulates macrophage activation via the SIRT1–p53 signaling network and regulates hepatocellular death in liver ischemia-reperfusion injury. Thus targeting this pathway in liver transplant recipients could be of therapeutic benefit.
KW - Heme oxygenase-1
KW - Innate immunity
KW - Ischemia-reperfusion injury
KW - Liver transplantation
KW - Myeloid-specific mutant mice
KW - P53
KW - Sirtuin 1
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U2 - 10.1016/j.jhep.2017.08.010
DO - 10.1016/j.jhep.2017.08.010
M3 - Article
C2 - 28842295
AN - SCOPUS:85029675721
SN - 0168-8278
VL - 67
SP - 1232
EP - 1242
JO - Journal of Hepatology
JF - Journal of Hepatology
IS - 6
ER -