Chemokine (C-C Motif) Receptor-Like 2 is not essential for lung injury, lung inflammation, or airway hyperresponsiveness induced by acute exposure to ozone.

Inhalation of ozone (O ₃ ), a gaseous air pollutant, causes lung injury, lung inflammation, and airway hyperresponsiveness. Macrophages, mast cells, and neutrophils contribute to one or more of these sequelae induced by O ₃ Furthermore, each of these aforementioned cells express chemokine (C-C motif) receptor-like 2 (Ccrl2), an atypical chemokine receptor that facilitates leukocyte chemotaxis. Given that Ccrl2 is expressed by cells essential to the development of O ₃ -induced lung pathology and that chemerin, a Ccrl2 ligand, is increased in bronchoalveolar lavage fluid (BALF) by O ₃ , we hypothesized that Ccrl2 contributes to the development of lung injury, lung inflammation, and airway hyperresponsiveness induced by O ₃ To that end, we measured indices of lung injury (BALF protein, BALF epithelial cells, and bronchiolar epithelial injury), lung inflammation (BALF cytokines and BALF leukocytes), and airway responsiveness to acetyl- β -methylcholine chloride (respiratory system resistance) in wild-type and mice genetically deficient in Ccrl2 (Ccrl2-deficient mice) 4 and/or 24 hours following cessation of acute exposure to either filtered room air (air) or O ₃ In air-exposed mice, BALF chemerin was greater in Ccrl2-deficient as compared to wild-type mice. O ₃ increased BALF chemerin in mice of both genotypes, yet following O ₃ exposure, BALF chemerin was greater in Ccrl2-deficient as compared to wild-type mice. O ₃ increased indices of lung injury, lung inflammation, and airway responsiveness. Nevertheless, no indices were different between genotypes following O ₃ exposure. In conclusion, we demonstrate that Ccrl2 modulates chemerin levels in the epithelial lining fluid of the lungs but does not contribute to the development of O ₃ -induced lung pathology.
(© 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)