RGS7 silence protects palmitic acid-induced pancreatic β-cell injury by inactivating the chemokine signaling pathway

Impaired insulin secretion due to pancreatic β-cell injury is an important cause of type 2 diabetes (T2D). Regulators of guanine nucleotide binding protein (G protein) signaling proteins played a key role in regulating insulin sensitivity in vivo. To explore the role of RGS7 on palmitic acid-induced pancreatic β-cell injury, pancreatic β-cells Beta-TC-6 and Min6 were treated with palmitic acid (PA) to similar type 2 diabetes (T2D) injury in vitro. The 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry were used to analyze cell viability, proliferation, and apoptosis, respectively. Enzyme-linked immunosorbent assay (ELISA) kits were used to analyze the changes of inflammation-related cytokines. The expression of gene and protein was measured by quantitative real-time PCR (qRT-PCR) and western blot. PA modeling induced apoptosis, increased levels of inflammation-related cytokines, and suppressed cell viability and proliferation of pancreatic β-cells. RGS7 silence markedly alleviated the cell injury induced by PA. RGS7 overexpression further aggravated apoptosis and inflammatory response in PA-induced pancreatic β-cells and inhibited cell viability and proliferation. It is worth noting that RGS7 activated the chemokine signaling pathway. Silence of the key gene of the chemokine signaling pathway could eliminate the negative effect of RGS7 on PA-induced pancreatic β-cells. RGS7 silence protects pancreatic β-cells from PA-induced injury by inactivating the chemokine signaling pathway.

The interaction, mechanism and function of GPR158-RGS7 cross-talk

GPR158 is an orphan G protein-coupled receptor (GPCR) that is broadly expressed in the brain and displays unique structural characteristics and signaling mechanisms. GPR158 is a binding partner for the regulator of G protein signaling 7 (RGS7) and augments its expression, subcellular localization, and catalytic activity. Recent cryo-electron microscopy (cryo-EM) studies have revealed the structure of GPR158 alone and in complex with RGS7. The GPR158-RGS7 complex is shown to be regulated by chronic stress exposure and is a modulator of stress-induced depression. This review highlights the signaling mechanism and function of GPR158-RGS7 and provides a context for the unique formation of GPCR-RGS complexes.

Fine mapping of the uterine leiomyoma locus on 1q43 close to a lncRNA in the RGS7-FH interval

Mutations in fumarate hydratase (FH) on chromosome 1q43 cause a rare cancer syndrome, hereditary leiomyomatosis and renal cell cancer (HLRCC), but are rare in nonsyndromic and common uterine leiomyoma (UL) or fibroids. Studies suggested that variants in FH or in a linked gene may also predispose to UL. We re-sequenced 2.3 Mb of DNA spanning FH in 96 UL cases and controls from the multiethnic NIEHS-uterine fibroid study, and in 18 HLRCC-associated UL probands from European families then selected 221 informative SNPs for follow-up genotyping. We report promising susceptibility associations with UL peaking at rs78220092 (P=7.0×10(-5)) in the RGS7-FH interval in African Americans. In race-combined analyses and in meta-analyses (n=916), we identified promising associations with risk peaking upstream of a non-protein coding RNA (lncRNA) locus located in the RGS7-FH interval closer to RGS7, and associations with tumor size peaking in the distal phospholipase D family, member 5 (PLD5) gene at rs2654879 (P=1.7×10(-4)). We corroborated previously reported FH mutations in nine out of the 18 HLRCC-associated UL cases and identified two missense mutations in FH in only two nonsyndromic UL cases and one control. Our fine association mapping and integration of existing gene profiling data showing upregulated expression of the lncRNA and downregulation of PLD5 in fibroids, as compared to matched myometrium, suggest a potential role of this genomic region in UL pathogenesis. While the identified variations at 1q43 represent a potential risk locus for UL, future replication analyses are required to substantiate our observation.