Expression of transient receptor potential channels on peripheral blood leukocytes of patients with chronic obstructive pulmonary disease

It is known that transient receptor potential (TRP) channels are receptors for reactive oxygen species and components of cigarette smoke, and therefore may be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD).Aim: To investigate the expression of TRPV1, TRPV4, TRPM8 and TRPA1 channels on peripheral blood leukocytes of COPD patients and healthy individuals and to establish its possible relationships with inflammatory markers and lung function parameters.Methodology and Research Methods. 23 patients with COPD of varying severity and 17 individuals without bronchial obstruction were examined. The expression of TRP channels on monocytes, lymphocytes and granulocytes was determined by indirect flow cytometry. Plasma concentrations of cytokines were measured in a multiplex assay. Lung function parameters were assessed by spirometry.Results. Monocytes from COPD patients were characterized by increased expression of TRPV1 (98.8 (97.6; 99.6)% vs. 97.8 (96.3; 98.6)%, p = 0.03) and TRPA1 (99.2 (98.7; 99.8)% vs. 95.1 (94.2; 98.4)%, p = 0.003). In addition, COPD was associated with an increased ratio of TRPV4/TRPM8 expression on monocytes (0.66 (0.51, 0.90) vs. 0.27 (0.12, 0.70), p = 0.02) and granulocytes (0.97 (0.86; 0.92) vs. 0.29 (0.06; 0.89), p = 0.003). TRPV4 expression on monocytes showed correlation with CXCL10 level (ρ = 0.55, p = 0.01), and for TRPM8 inverse relationships were found with the concentrations of IL-6 (ρ = -0.56, p = 0.02) and IL-10 (ρ = -0.55, p = 0.02). We did not find any associations between the expression of TRP channels and lung function parameters.Conclusion. Increased expression of TRPV1 and TRPA1, as well as an increased TRPV4/TRPM8 ratio on peripheral blood monocytes of COPD patients may indicate the contribution of these receptors to the proinflammatory activation of the cells and indicate possible prospects of TRP channels pharmacological modulation for the purpose of the disease therapy.