transforming-growth-factor-alpha and Diabetes-Mellitus

Diabetic retinopathy (DR) is a common complication of diabetes mellitus and it can lead to visual impairment and blindness. The loss of retinal pigment epithelial (RPE) cells is associated with the etiology of DR. Moreover, dysregulated circular RNAs (circRNAs) are implicated in DR progression. Therefore, this project aims to explore the role and potential mechanism of circ_0006667 in DR.. RPE cells (ARPE-19) were stimulated with high glucose (33 mM; HG group) for 24 h to establish the DR cell model. Circ_0006667, microRNA-7-5p (miR-7-5p), and transforming growth factor alpha (TGFA) expression was determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell viability, proliferation, and apoptosis were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry. CyclinD1, Cleaved-caspase-3, and TGFA protein levels were detected using western blot. Using Circinteractome and starBase analysis, the binding miR-7-5p and circ_0006667 or TGFA was predicted, and then validated using dual-luciferase reporter and RNA Immunoprecipitation (RIP).. Circ_0006667 expression was up-regulated in DR patients and HG-induced ARPE-19 cells. HG stimulation suppressed ARPE-19 cell proliferation and promoted cell apoptosis and inflammation, which were alleviated via circ_0006667 silence. Circ_0006667 acted as a molecular sponge for miR-7-5p, and circ_0006667 absence-mediated protective effects in HG-induced ARPE-19 cells were largely overturned by the interference of miR-7-5p. miR-7-5p directly targeted TGFA, and miR-7-5p overexpression protected ARPE-19 cells from HG-induced dysfunction largely by down-regulating TGFA. Circ_0006667 can up-regulate the expression of TGFA by sponging miR-7-5p in ARPE-19 cells.. Circ_0006667 silencing protected ARPE-19 cells from HG-induced dysfunction by mediating miR-7-5p/TGFA axis.

Topics: Cell Proliferation; Diabetes Mellitus; Diabetic Retinopathy; Epithelial Cells; Glucose; Humans; MicroRNAs; Retinal Pigments; Transforming Growth Factor alpha

The biological activity and regenerative medicine of bone marrow mesenchymal stem cells (BMSCs) have been focal topics in the broad fields of diabetic wound repair. However, the molecular mechanisms are still largely elusive for other cellular processes that are regulated during BMSC treatment. Our previous studies have shown that hypoxia is not only a typical pathological phenomenon of wounds but also exerts a vital regulatory effect on cellular bioactivity. In this study, the beneficial effects of hypoxic BMSCs on the cellular behaviors of epidermal cells and diabetic wound healing were investigated.. The viability and secretion ability of hypoxic BMSCs were detected. The autophagy, proliferation and migration of HaCaT cells cultured with hypoxic BMSCs-derived conditioned medium were assessed by estimating the expression of autophagy-related proteins, MTS, EdU proliferation and scratch assays. And the role of the SMAD signaling pathway during hypoxic BMSC-evoked HaCaT cell autophagy was explored through a series of in vitro gain- and loss-of-function experiments. Finally, the therapeutic effects of hypoxic BMSCs were evaluated using full-thickness cutaneous diabetic wound model.. First, we demonstrated that hypoxic conditions intensify HIF-1α-mediated TGF-β1 secretion by BMSCs. Then, the further data revealed that BMSC-derived TGF-β1 was responsible for the activation of epidermal cell autophagy, which contributed to the induction of epidermal cell proliferation and migration. Here, the SMAD signaling pathway was identified as downstream of BMSC-derived TGF-β1 to regulate HaCaT cell autophagy. Moreover, the administration of BMSCs to diabetic wounds increased epidermal autophagy and the rate of re-epithelialization, leading to accelerated healing, and these effects were significantly attenuated, accompanied by the downregulation of Smad2 phosphorylation levels due to TGF-β1 interference in BMSCs.. In this report, we present evidence that uncovers a previously unidentified role of hypoxic BMSCs in regulating epidermal cell autophagy. The findings demonstrate that BMSC-based treatment by restoring epidermal cell autophagy could be an attractive therapeutic strategy for diabetic wounds and that the process is mediated by the HIF-1α/TGF-β1/SMAD pathway.

Topics: Autophagy; Bone Marrow Cells; Diabetes Mellitus; Epidermal Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Mesenchymal Stem Cells; Signal Transduction; Smad Proteins; Transforming Growth Factor alpha; Transforming Growth Factor beta1; Wound Healing

Impaired wound healing results in significant morbidity for the surgical patient. The genetically diabetic (C57BL/KsJ-db/db) mouse is obese, hyperglycemic, insulin-resistant, and exhibits markedly impaired wound healing. Previous studies have demonstrated that the fibroblast mitogens, BB homodimer of platelet-derived growth factor (PDGF-BB) or basic fibroblast growth factor, plus insulin-like growth factor, act synergistically to enhance wound closure in the genetically diabetic mouse. The purpose of this study was to determine whether the keratinocyte mitogens, epidermal growth factor (EGF) or transforming growth factor-alpha (TGF-alpha), in combination with the fibroblast mitogen, PDGF-BB, would produce a similar synergistic enhancement in tissue repair. Full-thickness skin wounds created on the backs of diabetic mice received topical applications of vehicle (5% polyethylene glycol), PDGF-BB (10 micrograms), EGF (1 microgram), TGF-alpha (1 microgram), or the combination of PDGF (10 micrograms) and EGF (1 microgram) or TGF-alpha (1 microgram) for 5 consecutive days starting at wounding. Application of PDGF-BB or TGF-alpha alone to wounds in diabetic animals improved wound closure when compared to vehicle treatment. EGF did not affect healing and did not have any additive effects when combined with PDGF-BB. Significant improvements in wound closure were observed with the combination of PDGF-BB and TGF-alpha when compared to treatment with the individual growth factors. The PDGF-BB/TGF-alpha combination accelerated healing in the diabetic animals to a rate that was closer to that seen in nondiabetic mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Becaplermin; Diabetes Mellitus; Drug Synergism; Epidermal Growth Factor; Female; Mice; Platelet-Derived Growth Factor; Proto-Oncogene Proteins c-sis; Recombinant Proteins; Skin; Transforming Growth Factor alpha; Wound Healing; Wounds, Penetrating