Identification of Cysteine‐Rich Angiogenic Inducer 61 as a Potential Antifibrotic and Proangiogenic Mediator in Scleroderma

• Published in: Arthritis & rheumatology (Hoboken, N.J.) Vol. 71; no. 8; pp. 1350 - 1359
• Main Authors: Tsou, Pei‐Suen, Khanna, Dinesh, Sawalha, Amr H.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.08.2019
• Subjects: AKT protein; AMP; Angiogenesis; Biopsy; Cells, Cultured; Collagen (type I); Contraction; CYR61 protein; Cysteine; Cysteine-Rich Protein 61 - metabolism; Deactivation; Dermis - cytology; Endothelial cells; Endothelial Cells - metabolism; Fibroblasts; Fibroblasts - metabolism; Fibrosis; Gene expression; Genes; Growth factors; Histone deacetylase; Histone Deacetylases - metabolism; Humans; Inactivation; Kinases; mRNA; Neovascularization, Pathologic - genetics; Nitric oxide; Nitric-oxide synthase; Polymerase chain reaction; Protein kinase; Receptors; Ribonucleic acid; RNA; RNA, Messenger - metabolism; Scleroderma; Scleroderma, Systemic - genetics; Sclerosis; Senescence; Signal Transduction - genetics; siRNA; Skin; Skin - blood supply; Superoxide; Transforming Growth Factor beta - metabolism; Transforming growth factor-b; Vascular endothelial growth factor; Western blotting; Wound healing
• ISSN: 2326-5191; 2326-5205; 2326-5205
• DOI: 10.1002/art.40890

Objective We previously identified CYR61 as a histone deacetylase 5 (HDAC‐5)–repressed gene in systemic sclerosis (SSc; scleroderma) endothelial cells (ECs). When overexpressed, cysteine‐rich angiogenic inducer 61 (CYR‐61) promoted angiogenesis in SSc ECs. This study was undertaken to examine the role of CYR‐61 in fibrosis and determine the mechanisms involved in CYR‐61–mediated angiogenesis in SSc. Methods Dermal ECs and fibroblasts were isolated from biopsy specimens from healthy subjects and patients with SSc. CYR‐61 level was determined by quantitative polymerase chain reaction, Western blotting, and enzyme‐linked immunosorbent assay. CYR‐61 was overexpressed using a CYR61 vector or knocked down using small interfering RNA, and functional and mechanistic studies were then conducted in fibroblasts and ECs. Results Lower CYR61 messenger RNA levels were observed in dermal fibroblasts and ECs from SSc patients than in those from healthy controls. In SSc fibroblasts, overexpression of CYR‐61 led to significant reduction in the expression of profibrotic genes, including COL1A1 (P = 0.002) and ACTA2 (P = 0.04), and an increase in the expression of matrix‐degrading genes, including MMP1 (P = 0.002) and MMP3 (P =0.004), and proangiogenic VEGF (P = 0.03). The antifibrotic effect of CYR‐61 was further demonstrated by delay in wound healing, inhibition of gel contraction, inactivation of the transforming growth factor β pathway, and early superoxide production associated with senescence in SSc fibroblasts. In SSc ECs, overexpression of CYR‐61 led to increased production of vascular endothelial cell growth factor. The proangiogenic effects of CYR‐61 were mediated by signaling through αvβ3 receptors and downstream activation of AMP‐activated protein kinase, AKT, and the endothelial cell nitric oxide synthase/nitric oxide pathway system. Conclusion CYR‐61, which is epigenetically regulated by HDAC‐5, is a potent antifibrotic and proangiogenic mediator in SSc. Therapeutic intervention to promote CYR‐61 activity or increase CYR‐61 levels might be of benefit in SSc.