GSE203227
Myeloid FoxO1 in Nonalcoholic Steatohepatitis
Our objective is to determine the role of myeloid FoxO1 in regulating hepatic lipid metabolism and its contribution to nonalcoholic steatohepatitis (NASH) in mice. We generated mice with conditional FoxO1 depletion in myeloid cells, using the FoxO1-LoxP/LysM-Cre system. We then fed myeloid cell-conditional FoxO1-knockout and wild-type male mice a NASH-inducing diet for 25 weeks. Then mice in both groups were euthanized and the liver tissues were procured for the preparation of total RNAs, which were subjected to RNA-seq assay. While myeloid FoxO1 was upregulated in animal models and human subjects with NASH, the underlying mechanism is poorly understood. We found that myeloid cell conditional FoxO1-knockout mice were protected from developing NASH, culminating in the reduction of hepatic inflammation, steatosis and fibrosis. Mechanistically, FoxO1 counteracts Stat6 to skew macrophage polarization from M2 toward M1 signatures to perpetuate hepatic inflammation in NASH. FoxO1 appears as a pivotal mediator of macrophage activation in response to overnutrition and a therapeutic target for ameliorating hepatic inflammation to stem the disease progression from benign steatosis to NASH. Overall design: We used myeloid conditional FoxO1-knockout (n=4, male, 6-week old) and WT littermates (n=4, male, 6-week old) in this study. After feeding a NASH-inducing diet for 25 weeks, we euthanized mice in both groups (n=4/group) after 16-h fasting. Liver tissues were collected from euthanized mice and total liver RNAs were prepared for bulk RNA-seq analysis.