Estrogen-Related Receptor γ Plays a Key Role in Vascular Calcification Through the Upregulation of BMP2 Expression.

Vascular calcification which refers to ectopic mineralization in vascular cells is associated with several conditions, such as chronic kidney disease, atherosclerosis, and diabetes mellitus. Estrogen-related receptor (ERR)γ is a member of the orphan nuclear receptor superfamily, which plays diverse roles in regulating homeostatic and metabolic processes. However, the role of ERRγ in vascular calcification has not been investigated to date. The aim of the present study was to examine the role of ERRγ in vascular calcification. Vascular calcification was induced by treating rat aortic vascular smooth muscle cells with calcification medium. ERRγ expression in vascular smooth muscle cells was induced during calcification medium-induced vascular calcification. Adenovirus-mediated overexpression of ERRγ in vascular smooth muscle cells resulted in the upregulation of the expression of osteogenic genes, including runt-related transcription factor 2, osteopontin, and Msx2, and the downregulation of α-smooth muscle actin. Adenovirus-mediated overexpression of ERRγ induced bone morphogenetic protein 2 (BMP2) expression, leading to increased phosphorylation of the intracellular BMP2 effector proteins SMAD1/5/8. Collectively, these data suggested that ERRγ promotes dedifferentiation of vascular smooth muscle cells to an osteogenic phenotype during the vascular calcification process. Inhibition of endogenous ERRγ expression or activity using a specific siRNA or the selective inverse agonist GSK5182 attenuated vascular calcification and osteogenic gene expression in vitro and in vivo. The present results indicate that ERRγ plays a key role in vascular calcification by upregulating the BMP2 signaling pathway, suggesting that inhibition of ERRγ is a potential therapeutic strategy for the prevention of vascular calcification.

Kim JH ，Choi YK ，Do JY ，Choi YK ，Ha CM ，Lee SJ ，Jeon JH ，Lee WK ，Choi HS ，Park KG ，Lee IK ... -  《-》

Overexpression of c1q/tumor necrosis factor-related protein-3 promotes phosphate-induced vascular smooth muscle cell calcification both in vivo and in vitro.

Zhou Y ，Wang JY ，Feng H ，Wang C ，Li L ，Wu D ，Lei H ，Li H ，Wu LL ... -  《-》

Msx2 is required for vascular smooth muscle cells osteoblastic differentiation but not calcification in insulin-resistant ob/ob mice.

Obesity and diabetes potentiate vascular calcification by increasing vascular smooth muscle cells osteoblastic differentiation mediated by the transcription factor Msx2 and bone morphogenetic protein-2 signaling. However, Bmp-2/Msx2 crosstalk to induce VSMC osteogenic phenotype transition and calcification is poorly understood in diabetes. We aimed to investigate mechanisms underlying Bmp-2-driven VSMC osteogenic differentiation and calcification in leptin-deficient ob/ob mice. We incubated VSMC from ob/ob mice and wild type C57BL/6 littermates with or without Bmp-2. We used loss-of-function experiments to investigate the role of Msx2 in Bmp-2-induced ob/ob VSMC osteochondrogenic differentiation and calcification by transfecting Msx2 siRNA into VSMC. Baseline ob/ob VSMC and aorta showed increased Msx2, Runx2, alkaline phosphatase mRNA and protein expression, which further increased in Bmp-2-incubated ob/ob VSMC, therefore augmenting ob/ob VSMC calcification in comparison to wild type VSMC. Accordingly, signaling pathways to induce VSMC osteogenic differentiation, such as Smad1/5 phosphorylation increased in ob/ob versus wild type aorta. In comparison to wild type VSMC, Msx2 siRNA transfected VSMC decreased Bmp-2-dependent osteochondrogenic differentiation response by abrogating Msx2, Runx2, Alpl expression in ob/ob but not in wild type VSMC. Nonetheless, Msx2 inhibition did not decrease calcification in Bmp-2 stimulated ob/ob VSMC in vitro. Our data support a crucial role of Msx2 for ob/ob VSMC osteochondrogenic differentiation, however, Msx2 signaling alone is not sufficient for ob/ob VSMC calcification after Bmp-2 stimulation in vitro. These findings can be translated into novel perspectives for the understanding of the mechanisms and to provide therapeutic targets underlying vascular calcification in type 2 diabetes.

Andrade MC ，Carmo LS ，Farias-Silva E ，Liberman M ... -  《-》

Estrogen inhibits vascular calcification in rats via hypoxia-induced factor-1α signaling.

Wu X ，Zhao Q ，Chen Z ，Geng YJ ，Zhang W ，Zhou Q ，Yang W ，Liu Q ，Liu H ... -  《-》

Inhibition of FOXO1/3 promotes vascular calcification.

Vascular calcification is a characteristic feature of atherosclerosis, diabetes mellitus, and end-stage renal disease. We have demonstrated that activation of protein kinase B (AKT) upregulates runt-related transcription factor 2 (Runx2), a key osteogenic transcription factor that is crucial for calcification of vascular smooth muscle cells (VSMC). Using mice with SMC-specific deletion of phosphatase and tensin homolog (PTEN), a major negative regulator of AKT, the present studies uncovered a novel molecular mechanism underlying PTEN/AKT/FOXO (forkhead box O)-mediated Runx2 upregulation and VSMC calcification. SMC-specific PTEN deletion mice were generated by crossing PTEN floxed mice with SM22α-Cre transgenic mice. The PTEN deletion resulted in sustained activation of AKT that upregulated Runx2 and promoted VSMC calcification in vitro and arterial calcification ex vivo. Runx2 knockdown did not affect proliferation but blocked calcification of the PTEN-deficient VSMC, suggesting that PTEN deletion promotes Runx2-depedent VSMC calcification that is independent of proliferation. At the molecular level, PTEN deficiency increased the amount of Runx2 post-transcriptionally by inhibiting Runx2 ubiquitination. AKT activation increased phosphorylation of FOXO1/3 that led to nuclear exclusion of FOXO1/3. FOXO1/3 knockdown in VSMC phenocopied the PTEN deficiency, demonstrating a novel function of FOXO1/3, as a downstream signaling of PTEN/AKT, in regulating Runx2 ubiquitination and VSMC calcification. Using heterozygous SMC-specific PTEN-deficient mice and atherogenic ApoE(-/-) mice, we further demonstrated AKT activation, FOXO phosphorylation, and Runx2 ubiquitination in vascular calcification in vivo. Our studies have determined a new causative effect of SMC-specific PTEN deficiency on vascular calcification and demonstrated that FOXO1/3 plays a crucial role in PTEN/AKT-modulated Runx2 ubiquitination and VSMC calcification.

Deng L ，Huang L ，Sun Y ，Heath JM ，Wu H ，Chen Y ... -  《-》