TY - JOUR
T1 - Active p38α causes macrovesicular fatty liver in mice
AU - Darlyuk-Saadon, Ilona
AU - Bai, Chen
AU - Heng, Chew Kiat Matthew
AU - Gilad, Nechama
AU - Yu, Wei Ping
AU - Lim, Pei Yen
AU - Cazenave-Gassiot, Amaury
AU - Zhang, Yongliang
AU - Fred Wong, W. S.
AU - Engelberg, David
N1 - Publisher Copyright:
© 2021 National Academy of Sciences. All rights reserved.
PY - 2021/4/6
Y1 - 2021/4/6
N2 - One third of the western population suffers from nonalcoholic fatty liver disease (NAFLD), which may ultimately develop into hepatocellular carcinoma (HCC). The molecular event(s) that triggers the disease are not clear. Current understanding, known as the multiple hits model, suggests that NAFLD is a result of diverse events at several tissues (e.g., liver, adipose tissues, and intestine) combined with changes in metabolism and microbiome. In contrast to this prevailing concept, we report that fatty liver could be triggered by a single mutated protein expressed only in the liver. We established a transgenic system that allows temporally controlled activation of the MAP kinase p38α in a tissue-specific manner by induced expression of intrinsically active p38α allele. Here we checked the effect of exclusive activation in the liver. Unexpectedly, induction of p38α alone was sufficient to cause macrovesicular fatty liver. Animals did not become overweight, showing that fatty liver can be imposed solely by a genetic modification in liver per se and can be separated from obesity. Active p38α- induced fatty liver is associated with up-regulation of MUC13, CIDEA, PPARγ, ATF3, and c-jun mRNAs, which are up-regulated in human HCC. Shutting off expression of the p38α mutant resulted in reversal of symptoms. The findings suggest that p38α plays a direct causative role in fatty liver diseases and perhaps in other chronic inflammatory diseases. As p38α activity was induced by point mutations, it could be considered a proto-inflammatory gene (proto-inflammagene).
AB - One third of the western population suffers from nonalcoholic fatty liver disease (NAFLD), which may ultimately develop into hepatocellular carcinoma (HCC). The molecular event(s) that triggers the disease are not clear. Current understanding, known as the multiple hits model, suggests that NAFLD is a result of diverse events at several tissues (e.g., liver, adipose tissues, and intestine) combined with changes in metabolism and microbiome. In contrast to this prevailing concept, we report that fatty liver could be triggered by a single mutated protein expressed only in the liver. We established a transgenic system that allows temporally controlled activation of the MAP kinase p38α in a tissue-specific manner by induced expression of intrinsically active p38α allele. Here we checked the effect of exclusive activation in the liver. Unexpectedly, induction of p38α alone was sufficient to cause macrovesicular fatty liver. Animals did not become overweight, showing that fatty liver can be imposed solely by a genetic modification in liver per se and can be separated from obesity. Active p38α- induced fatty liver is associated with up-regulation of MUC13, CIDEA, PPARγ, ATF3, and c-jun mRNAs, which are up-regulated in human HCC. Shutting off expression of the p38α mutant resulted in reversal of symptoms. The findings suggest that p38α plays a direct causative role in fatty liver diseases and perhaps in other chronic inflammatory diseases. As p38α activity was induced by point mutations, it could be considered a proto-inflammatory gene (proto-inflammagene).
KW - Active variants
KW - Fatty liver
KW - Lipidosis
KW - Transgenic mice
KW - p38
UR - http://www.scopus.com/inward/record.url?scp=85103920278&partnerID=8YFLogxK
U2 - 10.1073/pnas.2018069118
DO - 10.1073/pnas.2018069118
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C2 - 33811139
AN - SCOPUS:85103920278
SN - 0027-8424
VL - 118
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 14
M1 - e2018069118
ER -