Estrogen‐related receptor α is involved in angiogenesis and skeletal muscle revascularization in hindlimb ischemia

Abstract

Skeletal muscle ischemia is a major consequence of peripheral arterial disease (PAD) or critical limb ischemia (CLI). Although therapeutic options for resolving muscle ischemia in PAD/CLI are limited, the issue is compounded by poor understanding of the mechanisms driving muscle vascularization. We found that nuclear receptor estrogen-related receptor alpha (ERRα) expression is induced in murine skeletal muscle by hindlimb ischemia (HLI), and in cultured myotubes by hypoxia, suggesting a potential role for ERRα in ischemic response. To test this, we generated skeletal muscle-specific ERRα transgenic (TG) mice. In these mice, ERRα drives myofiber type switch from glycolytic type IIB to oxidative type IIA/IIX myofibers, which are typically associated with more vascular supply in muscle. Indeed, RNA sequencing and functional enrichment analysis of TG muscle revealed that "paracrine angiogenesis" is the top-ranked transcriptional program activated by ERRα in the skeletal muscle. Immunohistochemistry and angiography showed that ERRα overexpression increases baseline capillarity, arterioles and non-leaky blood vessel formation in the skeletal muscles. Moreover, ERRα overexpression facilitates ischemic neoangiogenesis and perfusion recovery in hindlimb musculature of mice subjected to HLI. Therefore, ERRα is a hypoxia inducible nuclear receptor that is involved in skeletal muscle angiogenesis and could be potentially targeted for treating PAD/CLI.

Substance P Antagonism as a Novel Therapeutic Option to Enhance Efficacy of Cisplatin in Triple Negative Breast Cancer and Protect PC12 Cells against Cisplatin-Induced Oxidative Stress and Apoptosis

“…We isolated RNA from SUM 185 cells following 48 h treatment with cisplatin in the presence and absence of 10 µm AP, and controls included media alone with and without AP. For the RNA-Seq experiments, as previously [28], RNA was briefly extracted with a Purelink Kit (Ambion, Life Technologies, Carlsbad, CA, USA) following reversetranscription to cDNA using SuperScript III Reverse Transcriptase (Invitrogen, Waltham, MA, USA). We then performed enrichment of Poly (A)-tailed mRNA and prepared the RNAseq library using the UT Cancer Genomics Core Center facility following manufacturer's instructions outlined in the KAPA mRNA HyperPrep Kit (KK8581, Roche, Holding AG, city, Switzerland) and KAPA Unique Dual-indexed Adapter kit (KK8727, Roche).…”

Estrogen‐related receptor alpha is anAMPK‐regulated factor that promotes ischemic muscle revascularization and recovery in diet‐induced obese mice

“…The generation of muscle‐specific ERRα transgenic (TG) mice in our laboratory, on the C57Bl/6J background strain has been described previously 21 . In this transgenic line, the ERRα transgene is driven by a human alpha skeletal actin promotor to selectively overexpress ERRα in the mouse skeletal muscles.…”

“…Hindlimb ischemia (HLI) was induced in WT‐NCD, WT‐DIO and TG‐DIO mice ( N = 8–10) by unilateral femoral vessel ligation and transection, as we previously described 15,21 . In this model, ischemia was induced in left hindlimb, and the contralateral right hindlimb served as the control.…”

“…ERRα and ERRγ have recently emerged as key regulators of angiogenesis. Both ERRα and ERRγ stimulate a paracrine angiogenic gene program in the skeletal muscle involving up‐regulation of secretory pro‐angiogenic factors including Vegfa and Fgf1 15,21 . Furthermore, both ERRα and ERRγ overexpression in the skeletal muscle stimulates basal vascularization, as well as ischemic revascularization in the skeletal muscles of lean non‐diabetic mice 13,15,21 .…”

“…Both ERRα and ERRγ stimulate a paracrine angiogenic gene program in the skeletal muscle involving up‐regulation of secretory pro‐angiogenic factors including Vegfa and Fgf1 15,21 . Furthermore, both ERRα and ERRγ overexpression in the skeletal muscle stimulates basal vascularization, as well as ischemic revascularization in the skeletal muscles of lean non‐diabetic mice 13,15,21 . Other reports indicate that ERRα signaling in the endothelial cells may also contribute to regulation of angiogenesis 22,23 .…”