mi R-192-5p regulates lipid synthesis in non-alcoholic fatty liver disease through SCD-1

AIM To evaluate the levels of mi R-192-5 p in non-alcoholic fatty liver disease(NAFLD) models and demonstrate the role of mi R-192-5 p in lipid accumulation. METHODS Thirty Sprague Dawley rats were randomly divided into three groups, which were given a standard diet, a high-fat diet(HFD), and an HFD with injection of liraglutide. At the end of 16 weeks, hepatic mi R-192-5 p and stearoyl-Co A desaturase 1(SCD-1) levels were measured. Mi R-192-5 p mimic and inhibitor and SCD-1 si RNA were transfected into Huh7 cells exposed to palmitic acid(PA). Lipid accumulation was evaluated by oil red O staining and triglyceride assays. Direct interaction was validated by dual-luciferase reporter gene assays.RESULTS The HFD rats showed a 0.46-fold decrease and a 3.5-fold increase in hepatic mi R-192-5 p and SCD-1 protein levels compared with controls, respectively, which could be reversed after disease remission by liraglutide injection(P < 0.01). The Huh7 cells exposed to PA also showed down-regulation and up-regulation of mi R-192-5 p and SCD-1 protein levels, respectively(P < 0.01). Transfection with mi R-192-5 p mimic and inhibitor in Huh7 cells induced dramatic repression and promotion of SCD-1 protein levels, respectively(P < 0.01). Luciferase activity was suppressed and enhanced by mi R-192-5 p mimic and inhibitor, respectively, in wild-type SCD-1(P < 0.01) but not in mutant SCD-1. Mi R-192-5 p overexpression reduced lipid accumulation significantly in PA-treated Huh7 cells, and SCD-1 si RNA transfection abrogated the lipid deposition aggravated by mi R-192-5 p inhibitor(P < 0.01).CONCLUSION This study demonstrates that mi R-192-5 p has a negative regulatory role in lipid synthesis, which is mediated through its direct regulation of SCD-1.

Abnormal lipid synthesis as a therapeutic target for cancer stem cells

Cancer stem cells(CSCs)comprise a subpopulation of cancer cells with stem cell properties,which exhibit the characteristics of high tumorigenicity,self-renewal,and tumor initiation and are associated with the occurrence,metastasis,therapy resistance,and relapse of cancer.Compared with differentiated cells,CSCs have unique metabolic characteristics,and metabolic reprogramming contributes to the self-renewal and maintenance of stem cells.It has been reported that CSCs are highly dependent on lipid metabolism to maintain stemness and satisfy the requirements of biosynthesis and energy metabolism.In this review,we demonstrate that lipid anabolism alterations promote the survival of CSCs,including de novo lipogenesis,lipid desaturation,and cholesterol synthesis.In addition,we also emphasize the molecular mechanism underlying the relationship between lipid synthesis and stem cell survival,the signal transduction pathways involved,and the application prospect of lipid synthesis reprogramming in CSC therapy.It is demonstrated that the dependence on lipid synthesis makes targeting of lipid synthesis metabolism a promising therapeutic strategy for eliminating CSCs.Targeting key molecules in lipid synthesis will play an important role in anti-CSC therapy.