Overexpression Of Sortilin Promotes Pro-nerve Growth Factor-induced Apoptosis In Keloid Fibroblasts

Keloids is a benign tumor of the skin with unknown etiology, which is characterized by excessive skin fibrosis and abnormal healing of the wound. There is no safe and effective treatment method at present. Nerve growth factor (NGF) is one of the neurotrophin family members, NGF and proNGF regulates cell death with high affinity receptor tyrosine kinase (TrkA) and low affinity receptor (p75NTR); in the case of activation of different receptor nerve growth factor can play a biological role opposite, in combination with the p75NTR receptor can promote cell apoptosis, in contrast with the high affinity receptor TrkA is you can activate the NF-kB pathway to promote cell proliferation. The ability of cell apoptosis induced by proNGF was stronger than NGF, bonding strength proNGF and p75 were significantly higher than that with TrkA, proNGF is to form proNGF-p75-sortilin ligand receptor complexes, activation of signal transduction pathways, thereby inducing apoptosis. The Sortilin plays a key role in the ligand and the molecular switch, P75 control, play a key role in the process of apoptosis mediated by proNGF induced by Sortilin, also known as neurotensin receptor, type I membrane glycoprotein found in our previous studies, scar coreceptor expression Sortilin fiber cells was significantly lower than that in normal skin fibroblasts, which may be related to scar fibroblasts proliferation, but the mechanism still needs further research.Excessive proliferation and proNGF fibroblasts of keloid (nerve growth factor precursor) are closely related, but the specific mechanism is not clear, and the proNGF receptor in keloid fibroblasts and normal human skin as if there were differences in expression. Therefore, in this study, we observed Sortilin and p75 in human keloid fibroblasts and normal skin fibroblasts in differential expression and overexpression of Sortilin by gene engineering technique, to study the effect of proNGF induced apoptosis in KFs-Sortilin cells and explore the related mechanism.The First PartExpression of Sortilin in human hypertrophic scar fibroblasts and normal skin fibroblastsobjectiveTo study the expression of Sortilin in human Keloids fibroblasts (KFs) and normal skin fibroblasts (NFs), to explore the pathogenesis of the disease, and to provide theoretical basis for the treatment of scar.Method8 cases of normal skin tissue were collected, and 8 cases of normal skin fibroblasts and fibroblasts were cultured respectively. Using Real-Time PCR and Western blot method to detect the expression of sortilin in different cell volume difference, at the same time we used flow cytometry and Caspase-3 to detect of cell apoptosis.ResultWestern Blot and Real-Time PCR detected at mRNA and protein level on Sortilin fibroblasts and keloid formation were positive cells in normal skin, but Sortilin in keloid fibroblasts expression compared with normal skin fibroblasts expression was significantly reduced, the difference was statistically significant. There was no significant difference in the expression of p75NTR in the two kinds of cells.ConclusionThe expression of Sortilin in fibroblasts was significantly reduced, which may be related to the excessive proliferation of fibroblasts in the hypertrophic scar.The Second PartOverexpression of Sortilin promotes proNGF induced apoptosis in fibroblasts derived from hypertrophic scarObjectiveThe growth factor precursor of Sortilin in nerve (proNGF) fibroblast apoptosis induced in keloid, and analyze the signal transduction pathway and mechanism of action, and provide a theoretical basis for clinical treatment of keloid.MethodWe study the normal human skin fibroblasts and fibroblasts in the hypertrophic scar. Through gene engineering method to construct expression plasmid Sortilin, and transfected by lentiviral Sortilin expression of cultured keloid fibroblasts, then using flow cytometry and Caspase-3 detection of apoptosis of every group; finally through the Blot analysis of the Western signal transduction pathway.ResultThe expression of Sortilin was successfully constructed. After transfection, the expression of Sortilin, KFs-Sortilin, and KFs-Sortilin apoptosis was significantly enhanced, and the difference was statistically significant. Through Blot Western analysis of the signal pathway shows that the expression of NF-/NF kappa B signaling pathway was significantly reduced, the expression of Bax protein was significantly increased, the difference was statistically significant.ConclusionOverexpression of Sortilin significantly promoted proNGF induced apoptosis. The pathway of apoptosis is induced by inhibiting the PI3K/Akt/B NF NF-signaling pathway, and the expression of Bax is increased. In conclusion, our study showed that Sortilin enhanced KFs induced apoptosis of proNGF cells by increasing the expression of Bax and inhibition of PI3K/Akt activation of NF-kB signaling pathway, and provide a new target for Sortilin gene therapy of keloid disease.