Fatty Acid Desaturation Is Suppressed in Mir-26a/b Knockout Goat Mammary Epithelial Cells by Upregulating INSIG1

Abstract

MicroRNA-26 (miR-26a and miR-26b) plays a critical role in lipid metabolism, but its endogenous regulatory mechanism in fatty acid metabolism is not clear in goat mammary epithelial cells (GMECs). GMECs with the simultaneous knockout of miR-26a and miR-26b were obtained using the CRISPR/Cas9 system with four sgRNAs. In knockout GMECs, the contents of triglyceride, cholesterol, lipid droplets, and unsaturated fatty acid (UFA) were significantly reduced, and the expression of genes related to fatty acid metabolism was decreased, but the expression level of miR-26 target insulin-induced gene 1 (INSIG1) was significantly increased. Interestingly, the content of UFA in miR-26a and miR-26b simultaneous knockout GMECs was significantly lower than that in wild-type GMECs and miR-26a- and miR-26b-alone knockout cells. After decreasing INSIG1 expression in knockout cells, the contents of triglycerides, cholesterol, lipid droplets, and UFAs were restored, respectively. Our studies demonstrate that the knockout of miR-26a/b suppressed fatty acid desaturation by upregulating the target INSIG1. This provides reference methods and data for studying the functions of miRNA families and using miRNAs to regulate mammary fatty acid synthesis.

The Molecular Mechanism of circRNA-11228/miR-103/INSIG1 Pathway Regulating Milk Fat Synthesis in Bovine Mammary Epithelial Cells

“…MiRNAs are a class of short-stranded, non-coding RNAs that exert their regulatory effects by inducing degradation and inhibiting translation of target genes through specific binding to 3 ′ -UTR. A growing body of studies has demonstrated their regulatory roles in various biological processes [14,15], including cell proliferation [31], differentiation [32], apoptosis [33], and so on. In addition, it has been observed that a single miRNA may target multiple genes, thereby exerting a multifaceted impact [34].…”

“…MicroRNAs (miRNAs) can regulate multiple target genes, while individual genes can also be regulated by diverse miRNAs [14,15]. The critical role of miRNAs in cellular processes, such as cell proliferation, apoptosis, lipid and protein synthesis, and body metabolism, is attributed to their regulation of various signaling pathway molecules [16].…”