Exosomal circHIPK3 derived from umbilical cord-derived mesenchymal stem cells enhances skin fibroblast autophagy by blocking miR-20b-5p/ULK1/Atg13 axis.

BACKGROUND: Umbilical cord-derived mesenchymal stem cells (UCMSCs) could alleviate diabetes-induced injury. Hence, this investigation aimed to explore the role and mechanism of UCMSCs-derived exosomal circHIPK3 (exo-circHIPK3) in diabetes mellitus (DM). METHODS: HFF-1 cells were cultured in high glucose (HG) medium or normal medium, and treated with UCMSCs-derived exo-circHIPK3 or miR-20b-5p mimics or Unc-51-like autophagy activating kinase 1 (ULK1) overexpression vector. The surface markers of UCMSCs were analyzed using a flow cytometer. The differentiation potential of UCMSCs was evaluated using oil red O staining, alizarin red staining and alkaline phosphatase (ALP) staining. Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The miRNA expressions were analyzed by reverse transcription-quantitative polymerase chain reaction (qRT-PCR). Protein levels were quantified by western blot. An immunofluorescence staining was used for observing LC3 expression. The interaction between miR-20b-5p and circHIPK3, and between miR-20b-5b and ULK1 were identified by a RNA immunoprecipitation (RIP) assay and a luciferase reporter assay. RESULTS: Up-regulation of circHIPK3 was found in UCMSCs-derived exosomes. Exo-circHIPK3 decreased the miR-20b-5p level while increasing the contents of ULK1 and autophagy-related gene 13 (Atg13) in HG-induced fibroblasts. In addition, exo-circHIPK3 activated HG-induced fibroblast autophagy and proliferation. Overexpressed miR-20b-5p promoted fibroblast injury by inhibiting cell autophagy via the ULK1/Atg13 axis in HG conditions of high glucose. Moreover, exo-circHIPK3 enhanced autophagy and cell viability in HG-induced fibroblasts through the miR-20b-5p/ULK1/Atg13 axis. CONCLUSION: UCMSCs-derived exosomal circHIPK3 promoted cell autophagy and proliferation and accelerated the fibroblast injury repair by the miR-20b-5p/ULK1/Atg13 axis.

LncRNA GNAS-AS1 knockdown inhibits keloid cells growth by mediating the miR-188-5p/RUNX2 axis.

Keloid is a common dermis tumor, occurring repeatedly, affecting the quality of patients' life. Long non-coding RNAs (lncRNAs) have crucial regulatory capacities in skin scarring formation and subsequent scar carcinogenesis. The intention of this study was to investigate the mechanism and function of GNAS antisense-1 (GNAS-AS1) in keloids. Clinical samples were collected to evaluate the expression of GNAS-AS1, RUNX2, and miR-188-5p by qRT-PCR. The proliferation, migration, and invasion of HKF cells were detected by CCK-8, wound healing, and Transwell assays. The expression levels of mRNA and protein were examined through qRT-PCR and Western blot assay. Luciferase reporter assay was used to identify the binding relationship among GNAS-AS1, miR-188-5p, and Runt-related transcription factor 2 (RUNX2). GNAS-AS1 and RUNX2 expressions were remarkably enhanced, and miR-188-5p expression was decreased in keloid clinical tissues and HKF cells. GNAS-AS1 overexpression promoted cells proliferation, migration, and invasion, while GNAS-AS1 knockdown had the opposite trend. Furthermore, overexpression of GNAS-AS1 reversed the inhibitory effect of 5-FU on cell proliferation, migration, and invasion. MiR-188-5p inhibition or RUNX2 overexpression could enhance the proliferation, migration, and invasion of HKF cells. GNAS-AS1 targeted miR-188-5p to regulate RUNX2 expression. In addition, the inhibition effects of GNAS-AS1 knockdown on HKF cells could be reversed by inhibition of miR-188-5p or overexpression of RUNX2, while RUNX2 overexpression eliminated the suppressive efficaciousness of miR-188-5p mimics on HKF cells growth. GNAS-AS1 knockdown could regulate the miR-188-5p/RUNX2 signaling axis to inhibit the growth and migration in keloid cells. It is suggested that GNAS-AS1 may become a new target for the prevention and treatment of keloid.

UCMSCs-derived exosomal circHIPK3 promotes ulcer wound angiogenesis of diabetes mellitus via miR-20b-5p/Nrf2/VEGFA axis.

AIMS: Experiments confirmed that circular RNAs contributed to the pathogenesis of diabetic foot ulcers (DFUs). CircHIPK3 was upregulated in type 2 diabetes mellitus (T2DM), but its role in DFU remained unknown. Our study aimed to investigate the regulatory functions of exosomal circHIPK3 and its potential mechanisms in DFU. METHODS: Exosomal size and distribution, marker proteins, and circHIPK3 levels were evaluated by transmission electron microscope, ExoView R200, western blot, and qRT-PCR. Flow cytometry, MTT, Wound healing assays, and tube formation assays were used to assess the roles of exosomal circHIPK3 in high glucose (HG)-treated human umbilical vein endothelial cells (HUVECs). The relationships between Nrf2/VEGFA/circHIPK3 and miR-20b-5p, and between Nrf2 and VEGFA were determined by luciferase reporter assay and RNA immunoprecipitation. We used cell and mice models to investigate the mechanisms of exosomal circHIPK3 under diabetic conditions. RESULTS: CircHIPK3 was significantly upregulated in exo-circHIPK3 rather than exo-vector. Exo-circHIPK3 remarkably inhibited cell apoptosis but promoted cell proliferation, migration, and tube formation in HG-treated HUVECs. Luciferase reporter and RIP assays showed that miR-20b-5p targeted and inhibited Nrf2 and VEGFA, and circHIPK3 acted as a ceRNA of miR-20b-5p to inhibit the binding to its downstream genes Nrf2 and VEGFA. Mechanistically, circHIPK3 promoted cell proliferation, migration, and angiogenesis via downregulating miR-20b-5p to upregulate Nrf2 and VEGFA. However, the overexpressed miR-20b-5p could abolish the promoting effects of circHIPK3 overexpression on cell proliferation, migration, and tube formation under HG conditions. CONCLUSION: UCMSCs-derived exosomal circHIPK3 protected HG-treated HUVECs via miR-20b-5p/Nrf2/VEGFA axis. The exosomal circHIPK3 might be a therapeutic candidate to treat DFU.

LncRNA MALAT1 promotes wound healing via regulating miR-141-3p/ZNF217 axis.

BACKGROUND: The process of wound healing is complex. Increasing evidences have shown that lncRNA MALAT1 is abundant in fibroblasts and may be engaged in wound healing process. Therefore, we explored the mechanism of MALAT1 affecting wound healing. METHODS: The expression levels of MALAT1, miR-141-3p as well as ZNF217 in human fibroblast cells (HFF-1) were quantified by qRT-PCR. HFF-1 proliferation was measured by MTT, while migration was detected by wound healing assay. SMAD2 activation and matrix proteins expression were detected by western blotting. The interaction between miR-141-3p and MALAT1 or ZNF217 was further confirmed using the luciferase reporter gene assay. In vivo wound healing was assessed by full-thickness wound healing model on C57BL/6 mice. RESULT: Knockdown of MALAT1 as well as overexpression miR-141-3p remarkably inhibited the proliferation, migration and matrix protein expression in HFF-1 cells. MALAT1 directly targeted and inhibited the expression of miR-141-3p. MiR-141-3p suppressed the activation of TGF-ß2/SMAD2 signaling pathway by targeting ZNF217. Knockdown of MALAT1 inhibited wound healing process in mice. CONCLUSIONS: MALAT1 up-regulates ZNF217 expression by targeting miR-141-3p, thus enhances the activity of TGF-ß2/SMAD2 signaling pathway and promotes wound healing process. This investigation shed new light on the understanding of the role of MALAT1 in wound healing, and may provide potential target for the diagnosis or therapy of chronic wounds.