MicroRNA-146b-5p overexpression attenuates premature ovarian failure in mice by inhibiting the Dab2ip/Ask1/p38-Mapk pathway and γH2A.X phosphorylation

Objective: To examine the role of high-fat and high-sugar (HFHS) diet-induced oxidative stress, which is a risk factor for various diseases, in premature ovarian failure (POF).

Materials and methods: Ovarian granulosa cells (OGCs) were isolated from mice and cultured in medium supplemented with HFHS and poly (lactic-co-glycolic acid) (PLGA)-cross-linked miR-146b-5p nanoparticles (miR-146@PLGA). RNA and protein expression levels were examined using quantitative real-time polymerase chain reaction and Western blotting, respectively. HFHS diet-induced POF model mice were administered miR-146@PLGA.

Results: The ovarian tissue of mice fed a HFHS diet exhibited the typical pathological characteristics of POF. HFHS supplementation induced oxidative stress injury in the mouse OGCs, activation of the Dab2ip/Ask1/p38-Mapk signalling pathway and phosphorylation of γH2A.X in vitro and in vivo. The results of the luciferase reporter assay revealed that miR-146 specifically downregulated p38-Mapk14 expression. Meanwhile, co-immunoprecipitation and Western blot analyses revealed that HFHS supplementation upregulated nuclear p38-Mapk14 expression and consequently enhanced γH2A.X (Ser139) phosphorylation. The HFHS diet-induced POF mouse model treated with miR-146@PLGA exhibited downregulated p38-Mapk14 expression in the OGCs, mitigated OGC ageing and alleviated the symptoms of POF.

Conclusions: This study demonstrated that HFHS supplementation activates the Dab2ip/Ask1/p38-Mapk signalling pathway and promotes γH2A.X phosphorylation by inhibiting the expression of endogenous miR-146b-5p, which results in OGC ageing and POF development.