Transforming Growth Factor-Beta1 and Human Gingival Fibroblast-to-Myofibroblast Differentiation: Molecular and Morphological Modifications

Abstract

After oral mucosal injury, the healing response following specific steps that lead to wound closure and to tissue repair. Multiple cell populations are involved in this process; in particular, fibroblasts play a key role in the production of extracellular matrix (ECM). During wound healing the remodeling of ECM is a key stage to restore the tissue functionality through multifunctional fibroblast populations that are placed in the connective tissues of gingiva and periodontal ligament. Notably, a fibroblast sub-type (myofibroblast) is centrally involved in collagen synthesis and fibrillar remodeling. The present work evidenced the role of Transforming Growth Factor-beta1 (TGF-β1) to mediate human gingival fibroblasts (hGFs) differentiation into myofibroblasts derived from gingival fibroblasts (myo-hGFs). The morphological and functional features were analyzed through Confocal Laser Scanning Microscopy (CLSM), flow cytometry, and western blotting analyses. The specific markers, such as alpha-Smooth Muscle Actin (α-SMA), Vimentin, E-cadherin, β-catenin, and Smad 2/3, were modulated in myo-hGFs after the induction with TGF-β1, at different time points (24, 48, and 72 h). After 72 h of treatment TGF-β1 operates as an inducer of hGFs into myo-hGFs differentiation. We propose that TGF-β1 may promote in vitro the fibroblasts-to-myofibroblasts transition via the morphological and molecular modifications, as the induction of α-SMA, Vimentin, E-cadherin, β-catenin, and Smad 2/3.

Growth Factors, Reactive Oxygen Species, and Metformin—Promoters of the Wound Healing Process in Burns?

“…Several cell types including the resident fibroblast, adipocytes, fibrocytes, monocytes, mesenchymal cells, and epithelial/endothelial cells can be differentiated into myofibrob-lasts [30]. During the normal wound healing process, myofibroblasts significantly disappear at the end of the process via apoptosis [30]. Their presence in the wound tissue is correlated with scar production.…”

“…Their presence in the wound tissue is correlated with scar production. Moreover, myofibroblasts are involved in the production of ECM components and enhance the matrix elements' synthesis, such as laminin, glycosaminoglycans, and hyaluronic acid [30]. Marconi and co-workers observed that, in gingival tissue, during the wound healing process, cytokines and GFs stimulate the differentiation of resident fibroblasts into myofibroblasts [30].…”

“…Moreover, myofibroblasts are involved in the production of ECM components and enhance the matrix elements' synthesis, such as laminin, glycosaminoglycans, and hyaluronic acid [30]. Marconi and co-workers observed that, in gingival tissue, during the wound healing process, cytokines and GFs stimulate the differentiation of resident fibroblasts into myofibroblasts [30]. Therefore, TGF-β1 secreted mostly by M2 macrophages [20] represents the typical inducer of myofibroblast differentiation [30].…”

“…Marconi and co-workers observed that, in gingival tissue, during the wound healing process, cytokines and GFs stimulate the differentiation of resident fibroblasts into myofibroblasts [30]. Therefore, TGF-β1 secreted mostly by M2 macrophages [20] represents the typical inducer of myofibroblast differentiation [30]. Furthermore, the keratinocyte growth factor (KGF) stimulates the release of keratinocytes that may convert fibroblasts into myofibroblasts [29].…”

Functions of Matricellular Proteins in Dental Tissues and Their Emerging Roles in Orofacial Tissue Development, Maintenance, and Disease

“…Transforming growth factor-β (TGF-β), which is produced in the early stages of wound healing, is known to cause an increase in α-SMA expression through phosphorylation of Smad3 and plays a major role in myofibroblast differentiation [ 49 ]. Recently, Marconi and colleagues also showed that when human gingival fibroblasts (hGFs) are treated with TGFβ in vitro, they differentiate into myofibroblasts, determined by morphological and molecular modifications such as the induction of α-SMA, Vimentin, E-cadherin, β-catenin, and Smad 2/3 [ 50 ]. After the formation of actin-myosin contractile bundles, stress fibres, it is the neo-expression and incorporation of α-SMA that significantly augments the contractile activity of activated myofibroblasts [ 51 , 52 ].…”