Theranostics 2020; 10(10):4453-4465. doi:10.7150/thno.42354

Research Paper

PACAP neuropeptide promotes Hepatocellular Protection via CREB-KLF4 dependent autophagy in mouse liver Ischemia Reperfusion Injury

Zhengze Xue1,2*, Yu Zhang1,2*, Yuanxing Liu1,2*, Cheng Zhang1,2, Xiu-da Shen2, Feng Gao2, Ronald W. Busuttil2, Shusen Zheng1, Jerzy W. Kupiec-Weglinski2, Haofeng Ji2✉

1. Department of Surgery, Division of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang, China.
2. Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA, USA.
*These authors contributed equally to this work.

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Citation:
Xue Z, Zhang Y, Liu Y, Zhang C, Shen Xd, Gao F, Busuttil RW, Zheng S, Kupiec-Weglinski JW, Ji H. PACAP neuropeptide promotes Hepatocellular Protection via CREB-KLF4 dependent autophagy in mouse liver Ischemia Reperfusion Injury. Theranostics 2020; 10(10):4453-4465. doi:10.7150/thno.42354. Available from http://www.thno.org/v10p4453.htm

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Abstract

Organ ischemia reperfusion injury (IRI), associated with acute hepatocyte death, remains an unresolved problem in clinical orthotopic liver transplantation (OLT). Autophagy, an intracellular self-digesting progress, is responsible for cell reprograming required to regain post-stress homeostasis.

Methods: Here, we analyzed the cytoprotective mechanism of pituitary adenylate cyclase-activating polypeptide (PACAP)-promoted hepatocellular autophagy in a clinically relevant mouse model of extended hepatic cold storage (4 °C UW solution for 20 h) followed by syngeneic OLT.

Results: In contrast to 41.7% of liver graft failure by day 7 post-transplant in control group, PACAP treatment significantly improved graft survival (91.7% by day 14), and promoted autophagy-associated regeneration programs in OLT. In parallel in vitro studies, PACAP-enhanced autophagy ameliorated cellular damage (LDH/ALT levels), and diminished necrosis in H2O2-stressed primary hepatocytes. Interestingly, PACAP not only induced nuclear cAMP response element-binding protein (CREB), but also triggered reprogramming factor Kruppel-like factor 4 (KLF4) expression in IR-stressed OLT. Indeed, CREB inhibition attenuated hepatic autophagy and recreated hepatocellular injury in otherwise PACAP-protected livers. Furthermore, CREB inhibition suppressed PACAP-induced KLF4 expression, whereas KLF4 blockade abolished PACAP-promoted autophagy and neutralized PACAP-mediated hepatoprotection both in vivo and in vitro.

Conclusion: Current study documents the essential neural regulation of PACAP-promoted autophagy in hepatocellular homeostasis in OLT, which provides the emerging therapeutic principle to combat hepatic IRI in OLT.

Keywords: Liver Ischemia Reperfusion Injury, Orthotopic Liver Transplantation, PACAP, KLF4, CREB