Acute pulmonary inflammation is inhibited in CXCR3 knockout mice after short-term cigarette smoke exposure

Aim: CXCR3, via binding its specific ligand CXCL10, plays an important role in cigarette smoke (CS)-induced pulmonary inflammation. CXCR3 is preferentially expressed in activated T cells (chiefly CD8(+) T cells). The purpose of this study was to investigate the role of CXCR3 in CS-induced pulmonary injury using CXCR3 gene-deficient (CXCR3-/-) mice. Methods: Differences in the infiltration of inflammator cells and CD8(+) T cells and the expression of inflammatory mediators and chemokines in the bronchoalveolar lavage fluid and lungs at the mRNA and protein levels were compared between CXCR3-/- mice and wild-type (WT) mice at 2 h after 3 d of CS exposure. Results: Compared with their WT counterparts, the CXCR3-/- mice showed alleviated inflammation, as evidenced by fewer inflammatory cells, particularly cytotoxic CD8(+) T cells, in bronchoalveolar lavage fluid and lung tissues. At both the mRNA and protein levels, there were significantly lower levels of inflammatory and chemotactic cytokines, including TNF-alpha, interleukin-8, interferon-gamma, transforming growth factor-beta 1, and CXCL10 in the CXCR3-/- mice. Conclusion: Our data show that CXCR3 is important in recruiting inflammatory cells (particularly CD8(+) T cells) into the airways and lungs, as well as initiating inflammatory and fibrotic cytokines release at 2 h following a short-term CS insult. CXCR3 could be a novel target for the treatment of pulmonary inflammation induced by CS.