作者
Pallavi Subramanian,Sofia Gargani,Alessandra Palladini,Margarita Chatzimike,Michał Grzybek,Mirko Peitzsch,Anastasios D. Papanastasiou,Iryna Pyrina,Vasileios Ntafis,Bettina Gercken,Mathias Lesche,A. Petzold,Anupam Sinha,Marina Nati,Veera Raghavan Thangapandi,Ioannis Kourtzelis,Μαργαρίτα Ανδρεάδου,Anke Witt,Andreas Dahl,Ralph Burkhardt,Robert Haase,António Miguel de Jesus Domingues,Ian Henry,Nicola Zamboni,Peter Mirtschink,Kyoung‐Jin Chung,Jochen Hampe,Ünal Coskun,Dimitris L. Kontoyiannis,Triantafyllos Chavakis
摘要
NAFLD is initiated by steatosis and can progress through fibrosis and cirrhosis to HCC. The RNA binding protein human antigen R (HuR) controls RNAs at the posttranscriptional level; hepatocyte HuR has been implicated in the regulation of diet-induced hepatic steatosis. The present study aimed to understand the role of hepatocyte HuR in NAFLD development and progression to fibrosis and HCC.Hepatocyte-specific, HuR-deficient mice and control HuR-sufficient mice were fed either a normal diet or an NAFLD-inducing diet. Hepatic lipid accumulation, inflammation, fibrosis, and HCC development were studied by histology, flow cytometry, quantitative PCR, and RNA sequencing. The liver lipidome was characterized by lipidomics analysis, and the HuR-RNA interactions in the liver were mapped by RNA immunoprecipitation sequencing. Hepatocyte-specific, HuR-deficient mice displayed spontaneous hepatic steatosis and fibrosis predisposition compared to control HuR-sufficient mice. On an NAFLD-inducing diet, hepatocyte-specific HuR deficiency resulted in exacerbated inflammation, fibrosis, and HCC-like tumor development. A multi-omic approach, including lipidomics, transcriptomics, and RNA immunoprecipitation sequencing revealed that HuR orchestrates a protective network of hepatic-metabolic and lipid homeostasis-maintaining pathways. Consistently, HuR-deficient livers accumulated, already at steady state, a triglyceride signature resembling that of NAFLD livers. Moreover, up-regulation of secreted phosphoprotein 1 expression mediated, at least partially, fibrosis development in hepatocyte-specific HuR deficiency on an NAFLD-inducing diet, as shown by experiments using antibody blockade of osteopontin.HuR is a gatekeeper of liver homeostasis, preventing NAFLD-related fibrosis and HCC, suggesting that the HuR-dependent network could be exploited therapeutically.