Potential role of the Trpv4 c.1491+1G>A mutation in pulmonary fibrosis in a gene-edited mouse model

TRPV4 is a non-selective cation channel of the TRPV family and plays a key role in fibrosis, but its pathological mechanisms in genetically susceptible individuals remain unclear. This study aimed to investigate the potential role of the Trpv4 c.1491+1G>A splice-site mutation in pulmonary fibrosis using a gene-edited mouse model.

The mutation was identified in a family with autosomal dominant familial digital arthropathy-brachydactyly (FDAB). A corresponding gene-edited mouse model was generated using CRISPR/Cas9 technology. Histopathological analysis, single-cell RNA sequencing (scRNA-seq), qPCR, Western blot, and immunofluorescence co-staining were employed to assess phenotypic, transcriptomic, and molecular changes in the lungs.

The model mice exhibited skeletal abnormalities and multi-organ damage, with pronounced pulmonary fibrosis. In the lung tissues of homozygous mutant (Trpv4-Hom) mice, wild-type Trpv4 expression was significantly reduced, accompanied by thickened alveolar septa, pulmonary congestion, and increased collagen deposition. scRNA-seq revealed a decrease in the proportions of alveolar macrophages and NK cells, while Clara cells, fibroblasts, mesothelial cells, and alveolar type II cells increased. The ALCAM-CD6 and MIF-CD74 signaling axes were significantly upregulated. qPCR confirmed the transcriptional upregulation of Alcam, Cd6, Cd74, and Mif; Western blot further validated the increased protein levels of ALCAM, CD6, and CD74; and immunofluorescence confirmed the enhanced co-localization of MIF and CD74 in lung tissue.

The Trpv4 c.1491+1G>A mutation is associated with exacerbated pulmonary fibrosis, altered lung cellular composition, disrupted ALCAM-CD6 immune regulatory pathways and MIF signaling homeostasis, and enhanced pro-fibrotic cell communication. These findings provide novel molecular targets for the development of anti-fibrotic therapies targeting this pathway.