P2Y12 Receptor Antagonist Clopidogrel Attenuates Lung Inflammation Triggered by Silica Particles.

Patricia Teixeira Santana,Augusto Shuiti Tamura,Carolyne Lalucha Alves Lima Da Graça,Marcos Vinicius Rangel-Ferreira,Mariana Nascimento Machado,Robson Coutinho-Silva,Debora Souza Faffe,Walter Araujo Zin,Christina Maeda Takiya,Tatiana Luna-Gomes

doi:10.3389/fphar.2020.00301

Abstract

Silicosis is an occupational lung disease caused by inhalation of silica particles. It is characterized by intense lung inflammation, with progressive and irreversible fibrosis, leading to impaired lung function. Purinergic signaling modulates silica-induced lung inflammation and fibrosis through P2X7 receptor. In the present study, we investigate the role of P2Y12, the G-protein-coupled subfamily prototype of P2 receptor class in silicosis. To that end, BALB/c mice received an intratracheal injection of PBS or silica particles (20 mg), without or with P2Y12 receptor blockade by clopidogrel (20 mg/kg body weight by gavage every 48 h) – groups CTRL, SIL, and SIL + Clopi, respectively. After 14 days, lung mechanics were determined by the end-inflation occlusion method. Lung histology was analyzed, and lung parenchyma production of nitric oxide and cytokines (IL-1β, IL-6, TNF-α, and TGF-β) were determined. Silica injection reduced animal survival and increased all lung mechanical parameters in relation to CTRL, followed by diffuse lung parenchyma inflammation, increased neutrophil infiltration, collagen deposition and increased pro-inflammatory and pro-fibrogenic cytokine secretion, as well as increased nitrite production. Clopidogrel treatment prevented silica-induced changes in lung function, and significantly reduced lung inflammation, fibrosis, as well as cytokine and nitrite production. These data suggest that inhibition of P2Y12 signaling improves silica-induced lung inflammation, preventing lung functional changes and mortality. Our results corroborate previous observations of silica-induced lung changes and expand the understanding of purinergic signaling in this process.

Highlights

Silicosis is an occupational pneumoconiosis caused by inhalation of silica particles, which remains a health problem for workers in many industries, including mining and civil construction (Kauppinen et al, 2000; Bhagia, 2012)
To better understand the role of purinergic signaling in silica-induced lung inflammation, we investigated the participation of P2Y12 receptor in the onset of silicosis
Clopidogreltreated mice showed preserved areas of lung parenchyma with morphological delimitation of the alveolar septa, significantly fewer neutrophil infiltration, as well as collagen fibers deposition compared with the SIL group (Figures 3C,D)

Summary

Introduction

Silicosis is an occupational pneumoconiosis caused by inhalation of silica particles (free crystalline silicon dioxide), which remains a health problem for workers in many industries, including mining and civil construction (Kauppinen et al, 2000; Bhagia, 2012). Silica may produce acute (accelerated silicosis) or various forms of chronic silicosis (Borges et al, 2002; Castranova et al, 2002; Hnizdo and Vallyathan, 2003; Langley et al, 2004; Rimal et al, 2005). Both high-dose acute and low-dose chronic silica exposures induce granulomatous changes in the lungs. The risk of disease is related to lifetime cumulative exposure and to the amount of inhaled crystalline silica, which, in turn, depends on the concentration and the size of respirable particles, as well as on individual susceptibility (Leung et al, 2012)

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