AB0089 SILDENAFIL COUNTERACTS THE ACTIVATION OF CXCR3/CXCL10, -11 AXIS IN SCLERODERMA FIBROBLASTS EXPOSED TO REACTIVE OXYGEN SPECIES
Authors: C. Antinozzi, I. Dimauro, P. Sgrò, D. Caporossi, F. Del Galdo, L. DI Luigi
Journal: Annals of the Rheumatic Diseases (2021)

Background: Oxidative stress associated with vascular damage represents one the major contributor in the pathogenesis of systemic sclerosis (SSc) [1]. Indeed, different studies demonstrated that excessive free radicals production can contribute to the activation of fibrotic process in the skin and visceral organs [1]. CXCL10 and CXCL11, together with their receptor CXCR3, are involved in vascular damage and in fibrosis [2]. Furthermore, these chemokines have been proposed as biomarkers of vascular damage progression and severe SSc prognosis [3]. Emerging evidences highlight the beneficial effects of the phosphodiesterase type 5 (PDE5) inhibitor, sildenafil, to protect different cell types from reactive oxygen species (ROS)-induced DNA damage, in vitro [3]. This effect has been linked to modulation of CXCL10 concentration in different pathological conditions [4,5]. Objectives: Here we set out to investigate the effects of sildenafil, in modulating the CXCR3/CXCL10, -11 inflammatory axis in dermal fibroblasts exposed to oxidative stress, in vitro . Methods: Human dermal fibroblasts isolated by SSc skin biopsies were treated for 24h with 100µM of hydrogen peroxide (H 2 O 2 ), in the presence or not of sildenafil (1µM). Dermal fibrobalsts from healthy skin were used as controls. CXCL10 and CXCL11 were evaluated in cell medium by luminex technology assay; expression of chemokine receptor (CXCR)3 and peroxisome proliferator-activated receptor (PPARγ) (a regulator of CXCL10,-11 mRNA) was evaluated by western blot assay. Results: As showed in figure 1, SSc fibroblasts (grey bar) showed similar basal levels of CXCL10 (A) and CXCL11 (B) to healthy controls (black bar). H 2 O 2 induced a significant increase of both chemokines only in SSc fibroblasts (by 4.6 fold for CXCL10 and by 4.2 fold for CXCL11) (*P&lt;0.05 and **P&lt;0.01 vs. c; # P&lt;0.05 vs . healthy controls). Sildenal pre-incubation reduced by approximatively 50% the effects of H 2 O 2 on chemokines release (Figure 1A and B) ( § P&lt;0.05 vs. H 2 O 2 ), and reduced the expression of CXCR3 and PPARγ induced by hydrogen peroxyde exposure (data not shown). Conclusion: In vitro study on dermal fibroblasts support clinical studies to determine the efficacy of sildenafil in the preventing tissue damage and fibrosis in SSc, by reducing the pro-inflammatory activation induced by oxidative stress. References: [1]Di Luigi L, Sgrò P, Duranti G, Sabatini S, Caporossi D, Del Galdo F, Dimauro I, Antinozzi C. Sildenafil Reduces Expression and Release of IL-6 and IL-8 Induced by Reactive Oxygen Species in Systemic Sclerosis Fibroblasts. Int J Mol Sci. 2020 Apr 30;21(9):3161. doi: 10.3390/ijms21093161. PMID: 32365773; PMCID: PMC7246497. [2]Koper OM, Kamińska J, Sawicki K, Kemona H. CXCL9, CXCL10, CXCL11, and their receptor (CXCR3) in neuroinflammation and neurodegeneration. Adv Clin Exp Med. 2018 Jun;27(6):849-856. doi: 10.17219/acem/68846. PMID: 29893515. [3]Crescioli C, Corinaldesi C, Riccieri V, Raparelli V, Vasile M, Del Galdo F, Valesini G, Lenzi A, Basili S, Antinozzi C. Association of circulating CXCL10 and CXCL11 with systemic sclerosis. Ann Rheum Dis. 2018 Dec;77(12):1845-1846. doi: 10.1136/annrheumdis-2018-213257. Epub 2018 May 14. PMID: 29760155; PMCID: PMC6241615. [4]Giannattasio S, Corinaldesi C, Colletti M, Di Luigi L, Antinozzi C, Filardi T, Scolletta S, Basili S, Lenzi A, Morano S, Crescioli C. The phosphodiesterase 5 inhibitor sildenafil decreases the proinflammatory chemokine IL-8 in diabetic cardiomyopathy: in vivo and in vitro evidence. J Endocrinol Invest. 2019 Jun;42(6):715-725. doi: 10.1007/s40618-018-0977-y. Epub 2018 Nov 10. PMID: 30415310; PMCID: PMC6531405. [5]You N, Li J, Huang X, Wu K, Tang Y, Wang L, Li H, Mi N, Zheng L. COMMD7 activates CXCL10 production by regulating NF-κB and the production of reactive oxygen species. Mol Med Rep. 2018 May;17(5):6784-6788. doi: 10.3892/mmr.2018.8706. Epub 2018 Mar 8. PMID: 29532873. Disclosure of Interests: None declared