Increased activity of MAPKAPK2 within mesenchymal cells as a target for inflammation associated fibrosis in Crohn’s Disease

Abstract

Abstract Background Mesenchymal stromal cells are suggested to play a critical role in the Crohn’s Disease (CD) associated fibrosis. MAPKAPK2 (MK2) has emerged as a potential therapeutic target to reduce inflammation in CD. However, cell-specific pattern of pMK2 activation and its role in the CD associated fibrosis are unknown. The objectives of this study were to evaluate cell-specific changes in MK2 activity between predominantly inflammatory CD versus CD with fibrotic complication and define the role of stromal cell-specific MK2 activation in CD-associated fibrosis. Methods CD tissue, CD tissue derived mesenchymal stromal cells known as myo-/fibroblasts (CD-MFs), fibroblast specific MK2 conditional KO mice were used. Results We observed that in the inflamed area of predominantly inflammatory CD, high MK2 activity was equally distributed between mesenchymal and hematopoietic cells. By contrast, in CD with fibrotic complications, high MK2 activity was mostly associated with mesenchymal stromal cells. Using ex vivo CD tissue explants and IL-10KO murine colitis model, we demonstrated that pro-fibrotic responses are significantly reduced by treatment with the MK2 inhibitor PF-3644022. Inhibition of MK2 activity in primary cultures of CD-MFs significantly reduced basal and TGF-β1-induced profibrotic responses. Using fibroblast-specific MK2 knockout mice in chronic DSS colitis, we demonstrated that fibroblast intrinsic MK2 signaling is among the key processes involved in the chronic inflammation induced profibrotic responses. Conclusions Our data suggest that activation of MK2 within fibroblasts contributes to the chronic inflammation induced fibrosis in CD and that targeting MK2 has potential for the development of novel therapeutic approaches for fibrosis in CD.