Nestin identifies a subpopulation of rat ventricular fibroblasts and participates in cell migration .

Fibroblast progenitor cells migrate to the endocardial region during cardiogenesis and the migration of ventricular fibroblasts to the ischemically-damaged region of the infarcted adult heart is a seminal event of reparative fibrosis. The intermediate filament protein nestin participates in cell migration and is expressed in subpopulation of scar-derived myofibroblasts. The present study tested the hypothesis that fibroblast progenitor cells express nestin and the intermediate filament protein drives the migratory phenotype of ventricular fibroblasts. Tcf21- and WT1-fibroblast progenitor cells identified in the epicardial/endocardial regions of the heart of E12,5-13,5-day embryonic mice predominantly expressed nestin. Nuclear Tcf21/WT1 staining was identified in neonatal rat ventricular fibroblasts (NNVFbs) and a subpopulation co-expressed nestin. Nuclear Tcf21/WT1 expression persisted in adult rat ventricular fibroblasts whereas nestin protein levels were downregulated. Nestin-expressing NNVFbs exhibited a unique phenotype as the subpopulation was refractory to cell cycle re-entry in response to selective stimuli. Nestin- and nestin-scar derived rat myofibroblasts plated in matrigel unmasked a migratory phenotype characterized by the formation of lumen-like structures. The elongated membrane projections emanating from scar myofibroblasts delineating the boundary of lumen-like structures expressed nestin. Lentiviral shRNA-mediated nestin depletion inhibited the migratory response of NNVFbs as the wound radius was significantly larger compared to NNVFbs infected with the empty lentivirus. Thus, nestin represents a marker of embryonic Tcf21/WT1-fibroblast progenitor cells. The neonatal rat heart contains a distinct subpopulation of nestin-immunoreactive Tcf21/WT1-fibroblasts refractory to cell cycle re-entry and the intermediate filament protein may preferentially facilitate ventricular fibroblast migration during physiological/pathological remodeling.