Restoration of lipid homeostasis between TG and PE by the LXRα-ATGL/EPT1 axis ameliorates hepatosteatosis

Converting lipid disturbances in response to energy oversupply into healthy lipid homeostasis is a promising therapy to alleviate hepatosteatosis. Our clinical studies found that a further elevation of triglyceride (TG) in obese patients with the body mass index (BMI) greater than 28 was accompanied by a further reduction of phosphatidylethanolamine (PE). Shorter survival and poor prognosis were shown for the patients with high TG and low PE levels. Liver X receptor alpha (LXR alpha) knockout mice aggravated high-fat diet (HFD)-induced obesity and lipid disorders, making the TG enrichment and the PE decrease more pronounced according to the liver lipidomics analysis. The RNA-seq from mice liver exhibited that these metabolism disorders were attributed to the decline of Atgl (encoding the TG metabolism enzyme ATGL) and Ept1 (encoding the PE synthesis enzyme EPT1) expression. Mechanistic studies uncovered that LXR alpha activated the ATGL and EPT1 gene via direct binding to a LXR response element (LXRE) in the promoter. Moreover, both the supplement of PE in statin or fibrate therapy, and the LXR alpha inducer (oridonin) ameliorated cellular lipid deposition and lipotoxicity. Altogether, restoration of lipid homeostasis of TG and PE via the LXR alpha-ATGL/EPT1 axis may be a potential approach for the management of hepatosteatosis and metabolic syndrome.

Automated summary

Regulating lipid metabolism balance to achieve a healthy lipid homeostasis may be a promising therapy for alleviating hepatosteatosis. Clinical studies have found that in obese patients with a body mass index (BMI) greater than 28, an increase in triglycerides (TG) is accompanied by a decrease in phosphatidylethanolamine (PE). Patients with high TG and low PE levels have shorter survival and poor prognosis.