The Role of COUP-TFII in Striated Muscle Development and Disease

Astragaloside IV attenuates sunitinib-associated cardiotoxicity by inhibiting COUP-TFII

Sunitinib (SU) is widely used to treat solid tumors but it can be cardiotoxic and often leads to drug withdrawn or discontinuation. Astragaloside IV (ASIV) is the essential active component of the Chinese herb Astragalus membranaceus which shows potential cardioprotective effects. Herein, we investigated the effect of ASIV on SU-associated cardiotoxicity and its mechanisms. We showed that ASIV significantly ameliorated SU-induced myocardial injury in mice, as evidenced by an improvement in left ventricular ejection fraction (EF) and a decrease in blood pressure and serum concentration of myocardial injury markers. ASIV attenuated SU-induced myocardial inflammatory infiltration and fibrotic lesions. In addition, ASIV suppressed SU-induced myocardial oxidative stress and apoptosis both in vitro and in vivo. Furthermore, SU increased COUP-TFII expression both in mRNA and protein levels in mice myocardial tissue, primary neonatal rat cardiomyocytes (NRCMs) and H9c2 cell lines, and this effect was rescued by ASIV. Knockdown of COUP-TFII reduced the oxidative stress and apoptosis induced by SU in NRCMs and H9c2 cell lines. However, the overexpression of COUP-TFII blocked the protective effects of ASIV on SU-treated cardiomyocytes. Thus, our results demonstrated that ASIV ameliorated SU-indued cardiotoxicity by inhibiting COUP-TFII, suggesting that ASIV might be a potential therapeutic strategy for the prevention of SU-associated cardiotoxicity.

Small-molecule inhibitor targeting orphan nuclear receptor COUP-TFII for prostate cancer treatment

The orphan nuclear receptor COUP-TFII is expressed at a low level in adult tissues, but its expression is increased and shown to promote progression of multiple diseases, including prostate cancer, heart failure, and muscular dystrophy. Suppression of COUP-TFII slows disease progression, making it an intriguing therapeutic target. Here, we identified a potent and specific COUP-TFII inhibitor through high-throughput screening. The inhibitor specifically suppressed COUP-TFII activity to regulate its target genes. Mechanistically, the inhibitor directly bound to the COUP-TFII ligand-binding domain and disrupted COUP-TFII interaction with transcription regulators, including FOXA1, thus repressing COUP-TFII activity on target gene regulation. Through blocking COUP-TFII's oncogenic activity in prostate cancer, the inhibitor efficiently exerted a potent antitumor effect in xenograft mouse models and patient-derived xenograft models. Our study identified a potent and specific COUP-TFII inhibitor that may be useful for the treatment of prostate cancer and possibly other diseases.

COUP-TFII in Health and Disease

The nuclear receptors (NRs) belong to a vast family of evolutionary conserved proteins acting as ligand-activated transcription factors. Functionally, NRs are essential in embryogenesis and organogenesis and in adulthood they are involved in almost every physiological and pathological process. Our knowledge of NRs action has greatly improved in recent years, demonstrating that both their expression and activity are tightly regulated by a network of signaling pathways, miRNA and reciprocal interactions. The Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII, NR2F2) is a NR classified as an orphan due to the lack of a known natural ligand. Although its expression peaks during development, and then decreases considerably, in adult tissues, COUP-TFII is an important regulator of differentiation and it is variably implicated in tissues homeostasis. As such, alterations of its expression or its transcriptional activity have been studied and linked to a spectrum of diseases in organs and tissues of different origins. Indeed, an altered COUP-TFII expression and activity may cause infertility, abnormality in the vascular system and metabolic diseases like diabetes. Moreover, COUP-TFII is actively investigated in cancer research but its role in tumor progression is yet to be fully understood. In this review, we summarize the current understanding of COUP-TFII in healthy and pathological conditions, proposing an updated and critical view of the many functions of this NR.

Simultaneous miRNA and mRNA Transcriptome Profiling of Differentiating Equine Satellite Cells Treated with Gamma-Oryzanol and Exposed to Hydrogen Peroxide

Gamma-oryzanol (GO) is a popular supplement for performance horses, dogs, and humans. Previous studies indicated that GO supplementation decreases creatine kinase activity and lactate level after exercise and may affect oxidative stress in Thoroughbred horses. GO may change genes expression in equine satellite cells (ESC). The purpose of this study was to evaluate the effect of GO on miRNA, gene expression, oxidative stress, and cell damage and viability in differentiating ESC pretreated with hydrogen peroxide (H₂O₂). ESCs were obtained from a young horse’s skeletal muscle. ESCs were pre-incubated with GO (24 h) and then exposed to H₂O₂ for one hour. For the microRNA and gene expression assessment, the microarray technique was used. Identified miRNAs and genes were validated using real time-quantitative polymerase chain reaction. Several tests related to cell viability, cell damage, and oxidative stress were performed. The microarray analysis revealed differences in 17 miRNAs and 202 genes between GO-treated and control ESC. The tests related to apoptosis, cell viability, and oxidative stress showed that GO affects these processes to varying degrees. Our results suggest that GO can change miRNA and gene expression and may impact the processes involved in tissue repairing after an injury.