Activation of GPR30 inhibits cardiac fibroblast proliferation

Abstract

The incidence of left ventricular diastolic dysfunction significantly increases in postmenopausal women suggesting the association between estrogen loss and diastolic dysfunction. The in vivo activation of G protein-coupled estrogen receptor (GPR30) attenuates the adverse effects of estrogen loss on cardiac fibrosis and diastolic dysfunction in mRen2.Lewis rats. This study was designed to address the effects of GPR30 on cardiac fibroblast proliferation in rats. The expression of GPR30 in cardiac fibroblasts isolated from adult Sprague-Dawley rats was confirmed by RT-PCR, Western blot analysis, and immunofluorescence staining. Results from BrdU incorporation assays, cell counting, carboxyfluorescein diacetate succinimidyl ester labeling in conjunction with flow cytometry and Ki-67 staining showed that treatment with G1, a specific agonist of GPR30, inhibited cardiac fibroblast proliferation in a dose-dependent manner, which was associated with decreases in CDK1 and cyclin B1 protein expression. In the GPR30-KO cells, BrdU incorporation, and CDK1 and cyclin B1 expression significantly increased when compared to GPR30-intact cells. G1 had no effect on BrdU incorporation, CDK1 and cyclin B1 mRNA levels in GPR30-KO cells. In vivo studies showed increases in CDK1 and cyclin B1 mRNA levels, Ki-67-positive cells, and the immunohistochemistry staining of vimentin, a fibroblast marker, in the left ventricles from ovariectomized mRen2.Lewis rats versus hearts from ovary-intact littermates; two weeks of G1 treatment attenuated these adverse effects of estrogen loss. This study demonstrates that GPR30 is expressed in rat cardiac fibroblasts and activation of GPR30 limits proliferation of these cells likely via suppression of the cell cycle proteins, cyclin B1 and CDK1.

Activation of GPER ameliorates experimental pulmonary hypertension in male rats

“…In vitro studies have examined the mechanisms underlying the cardioprotective potential of GPER, focusing on its effects on cardiomyocyte hypertrophy and cardiac fibroblast proliferation. For example, G1 treatment attenuated angiotensin II-induced hypertrophy of H9c2 cardiomyocytes, with the GPER antagonist G15 inhibiting these effects of G1 (Wang et al, 2015). G1 inhibited the proliferation of exogenous GPER-expressing cardiac fibroblasts derived from male adult Sprague-Dawley rats (Wang et al, 2015).…”

“…For example, G1 treatment attenuated angiotensin II-induced hypertrophy of H9c2 cardiomyocytes, with the GPER antagonist G15 inhibiting these effects of G1 (Wang et al, 2015). G1 inhibited the proliferation of exogenous GPER-expressing cardiac fibroblasts derived from male adult Sprague-Dawley rats (Wang et al, 2015). This finding rationally explains why RVs from our MCT-injected rats treated chronically with G1 showed reduced levels of collagen deposition compared to MCT + vehicle rats.…”

“…The G protein-coupled estrogen receptor (GPER) has been extensively characterized as a protective target in animal models of left heart and systemic circulation remodeling and dysfunction. Nongenomic mechanisms are triggered, such as rapid estrogen-mediated activation of related protein-serine/threonine kinases (ERK1/2) and cyclic AMP (cAMP) generation, with subsequent induction of beneficial effects on the heart and arterial wall, including vasodilation, inhibition of smooth muscle cell proliferation, inhibition of inflammation, antioxidant effects, and endothelial/cardiac cell survival following injury (Alencar et al, 2016; Deschamps and Murphy, 2009; Haas et al, 2009; Jessup et al, 2010; Lindsey et al, 2009; Liu et al, 2016; Wang et al, 2012; Wang et al, 2015; Weil et al, 2010). Despite classical estrogen receptors (ERα and ERβ) signaling has been well characterized in different animal models of PH (Frump et al, 2015; Mair et al, 2014; Wright et al, 2015; Xu et al, 2013), there is a lack of robust exploration of GPER specific roles during experimental PH and in RV dysfunction.…”

GPER–novel membrane oestrogen receptor

“…GPER is expressed in cardiac myocytes (74) and fibroblasts (75). In intact female mRen2 rats, activation of GPER attenuates diastolic dysfunction induced by a high salt diet (76).…”

“…G-1 treatment decreases the proliferation of cardiac fibroblasts and the expression of cell cycle proteins CDK1 and cyclin B1 (75). In female mRen2 rats, GPER activation attenuates ovariectomy-induced increases in CDK1 and cyclin B1, proliferation marker Ki-67, and fibroblast marker vimentin in the left ventricle (81).…”