Role of DOCK2 and KCa3.1 in fibroblast-to-myofibroblast transformation

Excessive fibroblast-to-myofibroblast transformation is accompanied by injurious deposition of extracellular matrix components and tissue fibrosis. Fibrosis underlies many disease processes, including systemic sclerosis, idiopathic pulmonary fibrosis, liver cirrhosis, kidney fibrosis, and heart failure. Inhibiting fibroblast transformation is a major therapeutic strategy for the attenuation of these conditions. The aim of the present study is to determine the role of two proteins, dedicator of cytokinesis 2 (DOCK2) and the intermediate-conductance calcium-activated potassium channel (KCa3.1), in fibroblast-to-myofibroblast transformation. We hypothesized that DOCK2 and KCa3.1 stimulate fibroblast transformation. Cultured NIH/3T3 fibroblasts were treated with transforming growth factor β (TGFβ) in the presence and absence of inhibitors of DOCK2 (CPYPP, 10 μM) and KCa3.1 (TRAM-34, 100 nM). After 24 hours, mRNA was collected, transcribed into cDNA, and quantified with qRT-PCR. We found that CPYPP prevented TGFβ-induced transcriptional upregulation of the genes Acta2 (4.28 ± 0.18 vs 0.30 ± 0.01, n=4, p<0.001) and Col1a (2.51 ± 0.28 vs 0.14 ± 0.01, n=4, p<0.001), both indicators of fibroblast transformation. Similarly, TRAM-34 attenuated TGFβ-induced transcriptional upregulation of Acta2 (17.27 ± 0.81 vs 12.23 ± 1.26, n=4, p<0.01) with a similar trend for Col1a (1.88 ± 0.23 vs 1.33 ± 0.07, n=4, n.s.). We also determined that the role of DOCK2 in fibroblast transformation was at the post-transcriptional level since TGFβ did not increase mRNA expression of Dock2 (n=16). We conclude that DOCK2 and KCa3.1 are both involved in TGFβ-induced fibroblast-to-myofibroblast transformation. Future experiments will determine whether there is an interaction between DOCK2 and KCa3.1 in fibroblast transformation. NIH R01 HL151444 to DKB This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.