VEGF,FGF‐2 andTGFβ expression in the normal and regenerating epidermis of geckos: implications for epidermal homeostasis and wound healing in reptiles

Abstract

The skin is a bilayered organ that serves as a key barrier between an organism and its environment. In addition to protecting against microbial invasion, physical trauma and environmental damage, skin participates in maintaining homeostasis. Skin is also capable of spontaneous self-repair following injury. These functions are mediated by numerous pleiotrophic growth factors, including members of the vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and transforming growth factor β (TGFβ) families. Although growth factor expression has been well documented in mammals, particularly during wound healing, for groups such as reptiles less is known. Here, we investigate the spatio-temporal pattern of expression of multiple growth factors in normal skin and following a full-thickness cutaneous injury in the representative lizard Eublepharis macularius, the leopard gecko. Unlike mammals, leopard geckos can heal cutaneous wounds without scarring. We demonstrate that before, during and after injury, keratinocytes of the epidermis express a diverse panel of growth factor ligands and receptors, including: VEGF, VEGFR1, VEGFR2, and phosphorylated VEGFR2; FGF-2 and FGFR1; and phosphorylated SMAD2, TGFβ1, and activin βA. Unexpectedly, only the tyrosine kinase receptors VEGFR1 and FGFR1 were dynamically expressed, and only during the earliest phases of re-epithelization; otherwise all the proteins of interest were constitutively present. We propose that the ubiquitous pattern of growth factor expression by keratinocytes is associated with various roles during tissue homeostasis, including protection against ultraviolet photodamage and coordinated body-wide skin shedding.

S-adenosyl-L-methionine improves ventricular remodeling after myocardial infarction by regulating angiogenesis and fibrosis

“…VEGF is considered to be the most important vascular stimulating factor which induced multiple signaling pathways, and these signaling pathways coordinate various biological processes, such as endothelial cell maturation, angiogenesis and arterioles formation [19]. In addition, VEGF stimulates angiogenesis by activating VEGF receptor 2 signaling pathway [20]. The treatment of angiogenesis may protect against HF.…”

Anti-Aging Effects of GDF11 on Skin

“…Finally, injured skin is able to spontaneously self-repair, a process which is mediated by numerous pleiotrophic growth factors including members of the TGFβ and VEGF families. Before, during and after injury, epidermis keratinocytes express a large panel of growth factor ligands and receptors, including VEGF, VEGFR1, VEGFR2, phosphorylated Smad2, and TGFβ1, and activins [46]. As a member of the TGF-β superfamily, GDF11 activates the TGF-β signaling pathway by phosphorylating Smad2/3.…”

Negative air ions through the action of antioxidation, anti-inflammation, anti-apoptosis and angiogenesis ameliorate lipopolysaccharide induced acute lung injury and promote diabetic wound healing in rat

“…Skin is capable of spontaneous self-repair following injury. These functions are mediated by numerous pleiotrophic growth factors, including the vascular endothelial growth factor-2 (VEGFR-2) and transforming growth factor-β1 (TGF-β1) families [ 24 , 33 ]. We assessed the effect of NAIs on the expression of the VEGFR-2 and TGF-β1 in skin wound healing of rats.…”