Searching Novel Therapeutic Targets for Scleroderma: P2X7-Receptor Is Up-regulated and Promotes a Fibrogenic Phenotype in Systemic Sclerosis Fibroblasts

Daniela Gentile; Pietro E Lazzerini; Alessandra Gamberucci; Mariarita Natale; Enrico Selvi; Francesca Vanni; Alessandra Alì; Paolo Taddeucci; Silvia Del-Ry; Manuela Cabiati; Veronica Della-Latta; David J Abraham; Maria A Morales; Rosella Fulceri; Franco Laghi-Pasini; Pier L Capecchi

doi:10.3389/fphar.2017.00638

Searching Novel Therapeutic Targets for Scleroderma: P2X7-Receptor Is Up-regulated and Promotes a Fibrogenic Phenotype in Systemic Sclerosis Fibroblasts

Front Pharmacol. 2017 Sep 13:8:638. doi: 10.3389/fphar.2017.00638. eCollection 2017.

Authors

Daniela Gentile¹, Pietro E Lazzerini¹, Alessandra Gamberucci², Mariarita Natale¹, Enrico Selvi¹, Francesca Vanni¹, Alessandra Alì², Paolo Taddeucci¹, Silvia Del-Ry³, Manuela Cabiati³, Veronica Della-Latta³, David J Abraham⁴, Maria A Morales³, Rosella Fulceri², Franco Laghi-Pasini¹, Pier L Capecchi¹

Affiliations

¹ Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy.
² Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy.
³ Institute of Clinical Physiology, CNR, Pisa, Italy.
⁴ Division of Medicine, Department of Inflammation, Centre for Rheumatology and Connective Tissue Diseases, University College London, London, United Kingdom.

Abstract

Objectives: Systemic sclerosis (SSc) is a connective tissue disorder presenting fibrosis of the skin and internal organs, for which no effective treatments are currently available. Increasing evidence indicates that the P2X7 receptor (P2X7R), a nucleotide-gated ionotropic channel primarily involved in the inflammatory response, may also have a key role in the development of tissue fibrosis in different body districts. This study was aimed at investigating P2X7R expression and function in promoting a fibrogenic phenotype in dermal fibroblasts from SSc patients, also analyzing putative underlying mechanistic pathways. Methods: Fibroblasts were isolated by skin biopsy from 9 SSc patients and 8 healthy controls. P2X7R expression, and function (cytosolic free Ca²⁺ fluxes, α-smooth muscle actin [α-SMA] expression, cell migration, and collagen release) were studied. Moreover, the role of cytokine (interleukin-1β, interleukin-6) and connective tissue growth factor (CTGF) production, and extracellular signal-regulated kinases (ERK) activation in mediating P2X7R-dependent pro-fibrotic effects in SSc fibroblasts was evaluated. Results: P2X7R expression and Ca²⁺ permeability induced by the selective P2X7R agonist 2'-3'-O-(4-benzoylbenzoyl)ATP (BzATP) were markedly higher in SSc than control fibroblasts. Moreover, increased αSMA expression, cell migration, CTGF, and collagen release were observed in lipopolysaccharides-primed SSc fibroblasts after BzATP stimulation. While P2X7-induced cytokine changes did not affect collagen production, it was completely abrogated by inhibition of the ERK pathway. Conclusion: In SSc fibroblasts, P2X7R is overexpressed and its stimulation induces Ca²⁺-signaling activation and a fibrogenic phenotype characterized by increased migration and collagen production. These data point to the P2X7R as a potential, novel therapeutic target for controlling exaggerated collagen deposition and tissue fibrosis in patients with SSc.

Keywords: ERK; P2X7 receptor; collagen; dermal fibroblasts; fibrosis; systemic sclerosis.

Abstract

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