Background: Scar formation is a key process after myocardial infarction (MI), with crucial influence on patient prognosis and mortality. Cardiac fibroblasts (cFs) play a pivotal role in this process, as they become activated, differentiate into myofibroblast and secrete extracellular matrix (ECM) components. However, sustained activation results in pathological fibrotic remodeling, ultimately leading to impaired cardiac output. Cell Migration Inducing Protein (CEMIP) is highly expressed in the cFs and is involved in the depolymerization of hyaluronan, suggesting a potential role in post-MI remodeling.
Objectives: Or research group has lately demonstrated that Cemip deletion aggravates cardiac dysfunction following ischemia/reperfusion injury in mice. In this study we aim to investigate CEMIP´s role in the phenotypic transition of the cFs as well as the underlying mechanisms.
Methods: 12-16 weeks old C57BL/6J mice were used for the isolation of cFs, which were subsequently transfected with siRNA targeting Cemip. Fibroblast proliferation was assessed by flow cytometry using BrdU labeling, as well as by KI67 staining. Morphological characteristics and the expression of activation-associated genes were analyzed. Cell migration, cell contraction and 3D morphology were evaluated. Vinculin immunostaining was performed to assess focal adhesion formation, while qPCR was used to analyze integrin gene expression.
Results: Knock down of Cemip inhibited fibroblast proliferation and promoted myofibroblast transition. Cemip-KD cells exhibited hypercontractile phenotype and formed more dendritic extensions in a 3D-culture. In alignment with the altered morphology, Stathmin 1 expression was reduced, suggesting disruption of the microtubule system. Elevated Vinculin expression indicated enhanced focal adhesion formation.
Conclusion: According to our data CEMIP is a key regulator of the fibroblast-to-myofibroblast transition. We demonstrated that Cemip-deletion alters the cFs phenotype in both 2D and 3D model, further highlighting CEMIP´s impact on modulating cell-ECM interactions.
