Association of TRPV4 gene polymorphisms with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by airway epithelial damage, bronchoconstriction, parenchymal destruction and mucus hypersecretion. Upon activation by a broad range of stimuli, transient receptor potential vanilloid 4 (TRPV4) functions to control airway epithelial cell volume and epithelial and endothelial permeability; it also triggers bronchial smooth muscle contraction and participates in autoregulation of mucociliary transport. These functions of TRPV4 may be important for the regulation of COPD pathogenesis, so TRPV4 is a candidate gene for COPD. We genotyped 20 single nucleotide polymorphisms (SNPs) in TRPV4, and tested qualitative COPD and quantitative FEV1 and FEV1/(F)VC phenotypes in two independent large populations. The family population had 606 pedigrees including 1891 individuals, and the case–control sample included 953 COPD cases and 956 controls. Family-based association tests were performed in the family data. Logistic regression and linear models were used in the case–control data to replicate the association results. In the family data, seven out of 20 SNPs tested were associated with COPD (2.5 × 10−4 ≤ P ≤ 0.04) and six SNPs were associated with FEV1/VC (0.02 ≤ P ≤ 0.03) from family-based association tests (PBAT) analysis. Four out of the seven SNPs associated with COPD demonstrated replicated associations with the same effect directions in the case–control population (0.02 ≤ P ≤ 0.03). Significant haplotype associations supported the results of single SNP analyses. Thus, polymorphisms in the TRPV4 gene are associated with COPD.