1171-P: HORMAD1, a Novel Hypoxia-Inducible Factor-1 Target, Is Upregulated in Maternal Overnutrition-Induced Nonalcoholic Steatohepatitis (NASH)/Hepatocellular Carcinoma

Abstract

We investigated whether overnutrition during pregnancy were associated with the changes in gene expressions, oxygen metabolism, and vascular and hepatic parenchymal remodeling in fetal livers at mid gestational days E14.5 of dams fed a control diet (CD group) or a high-fat diet (HFD group) during pregnancy. Synchrotron-based phase-contrast micro-CT demonstrated embryos of HFD group showed hepatomegaly accompanied with the same size umbilical vein and less portal branching, which might result in liver hypoxia. Correspondingly, fetal livers of HFD group increased the expression of HIF-1alpha. To identify genes and pathways targeted by maternal overnutrition in fetal livers, we assayed mRNA levels with microarray. We identified 430 differentially expressed genes (DEGs) including 146 upregulated- and 284 downregulated genes in fetal livers of HFD group compared with those of CD group. The up-regulated DEGs were significantly enriched in DNA alkylation, bile secretion, and the down-regulated DEGs mainly enriched in neuronal system, cell maturation. Among upregulated DEGs, a cancer/testis antigen HORMAD1 was induced by hypoxia up to 30-fold compared with that in normoxia in primary mouse hepatocytes (PMH), and the genetic inhibition of HIF-1alpha by siRNAs abolished the stimulatory effect of hypoxia on Hormad1 expression. In addition, we found three putative hypoxia response elements within the mouse Hormad1gene. Interestingly, the tumor suppressor WW domain-containing oxidoreductase (WWOX), which inhibits the activity of HIF-1alpha, were remarkably decreased in hypoxia in PMH. Finally, HORMAD1 protein was upregulated in fetal livers and NASH-based HCC in offspring of HFD group at 15 weeks old. Our results suggest that WWOX-HIF-1alpha-HORMAD1 pathway might be involved in the development of NAFLD in offspring of obese and/or diabetic pregnant woman, and be an important therapeutic target of NASH/HCC. Disclosure T. Takiyama: None. Y. Takiyama: Other Relationship; Self; Gilead Sciences, Inc., Research Support; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Mochida Pharmaceutical Co., Ltd., Roche Diabetes Care, Taisho Pharmaceutical Co., Ltd. R. Bessho: None. H. Kitsunai: None. Y. Takeda: None. H. Sakagami: None. T. Sera: None. M. Nakamura: None. S. Horike: None. Y. Nishikawa: None.