Zhu LH, Wang A, Luo P, Wang X, Jiang DS, Deng W, Zhang X, Wang T, Liu Y, Gao L, Zhang S, Zhang X, Zhang J, Li H. Mindin/Spondin 2 inhibits hepatic steatosis, insulin resistance, and obesity via interaction with peroxisome proliferator-activated receptor α in mice.
J Hepatol 2014;
60:1046-54. [PMID:
24445216 DOI:
10.1016/j.jhep.2014.01.011]
[Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 12/16/2013] [Accepted: 01/06/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS
Obesity and its related pathologies, such as hepatic steatosis, are associated with chronic inflammation and insulin resistance (IR), which contribute to cardiovascular disease. Our previous studies indicated that Spondin 2 has a protective role in the context of cardiovascular and cerebrovascular diseases. Whether Spondin 2 is also associated with the development of hepatic steatosis and IR remains unclear.
METHODS
Wild-type mice, Spondin 2-knockout (KO) mice, hepatic-specific Spondin 2 transgenic (Spondin 2-TG) mice, high fat diet (HFD)-induced obese mice injected with an adenovirus expressing Spondin 2-specific shRNA or a Spondin 2 mutant and genetically obese (ob/ob) mice injected with an adenovirus expressing Spondin 2 were fed normal chow (NC) or HFD for indicated time to induce obesity, hepatic steatosis, inflammation, and IR. Biomedical, histological, and metabolic analyses were conducted to identify pathologic alterations in these mice. The molecular mechanisms of Spondin 2 functions were explored in mice and in hepatocytes or cell lines.
RESULTS
Consistent with Spondin 2 repression in the livers of HFD-induced and ob/ob mice, the Spondin 2-KO or hepatic-specific Spondin 2 knockdown mice exhibited more severe obesity, hepatic steatosis, inflammation, and IR upon HFD. Conversely, these pathological conditions were significantly improved in the Spondin 2-TG mice or Spondin 2-overexpressing ob/ob mice. Spondin 2 interacts with PPARα to regulate PPARα-target genes, thereby improving the pathological phenotypes. In contrast, the hepatic overexpression of mutant Spondin 2 without the PPARα-interacting domain failed to improve the aggravated phenotypes observed in the Spondin 2-KO mice.
CONCLUSION
Spondin 2 regulates hepatic lipid metabolism and alleviates hepatic steatosis, obesity, inflammation, and IR in mice via its interaction with PPARα.
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