GDF11 promotes wound healing in diabetic mice via stimulating HIF-1ɑ-VEGF/SDF-1ɑ-mediated endothelial progenitor cell mobilization and neovascularization.

Non-healing diabetic wounds (DW) are a serious clinical problem that remained poorly understood. We recently found that topical application of growth differentiation factor 11 (GDF11) accelerated skin wound healing in both Type 1 DM (T1DM) and genetically engineered Type 2 diabetic db/db (T2DM) mice. In the present study, we elucidated the cellular and molecular mechanisms underlying the action of GDF11 on healing of small skin wound. Single round-shape full-thickness wound of 5-mm diameter with muscle and bone exposed was made on mouse dorsum using a sterile punch biopsy 7 days following the onset of DM. Recombinant human GDF11 (rGDF11, 50 ng/mL, 10 µL) was topically applied onto the wound area twice a day until epidermal closure (maximum 14 days). Digital images of wound were obtained once a day from D0 to D14 post-wounding. We showed that topical application of GDF11 accelerated the healing of full-thickness skin wounds in both type 1 and type 2 diabetic mice, even after GDF8 (a muscle growth factor) had been silenced. At the cellular level, GDF11 significantly facilitated neovascularization to enhance regeneration of skin tissues by stimulating mobilization, migration and homing of endothelial progenitor cells (EPCs) to the wounded area. At the molecular level, GDF11 greatly increased HIF-1ɑ expression to enhance the activities of VEGF and SDF-1ɑ, thereby neovascularization. We found that endogenous GDF11 level was robustly decreased in skin tissue of diabetic wounds. The specific antibody against GDF11 or silence of GDF11 by siRNA in healthy mice mimicked the non-healing property of diabetic wound. Thus, we demonstrate that GDF11 promotes diabetic wound healing via stimulating endothelial progenitor cells mobilization and neovascularization mediated by HIF-1ɑ-VEGF/SDF-1ɑ pathway. Our results support the potential of GDF11 as a therapeutic agent for non-healing DW.

LncRNA ROR modulates myocardial ischemia-reperfusion injury mediated by the miR-185-5p/CDK6 axis.

LncRNAs and miRNAs are correlated with the pathogenesis of myocardial ischemia-reperfusion injury (MIRI). Whether lncRNA ROR or miR-185-5p plays a crucial role in MIRI is still unclear. In in-vitro, human cardiac myocytes (HCMs) were treated with hypoxia/reoxygenation (H/R). Wistar rats were used to set up an in-vitro I/R model by means of recanalization after ligation. Evaluation of the myocardial injury marker lactate dehydrogenase (LDH) in HCMs cells was performed. The expression of miR-185-5p and ROR, IL-1ß, and IL-18 were detected by qRT-PCR. ELISA was also performed to evaluate the secretion of IL-1ß and IL-18. Western blotting was carried out to determine CDK6, NLRP3, GSDMD-N, ASC, and cleaved-caspase1 protein expression. The relationship between miR-185-5p and CDK6 or ROR was confirmed by a dual-luciferase reporter assay. Our findings revealed that H/R treated HCMs showed a significantly decreased miR-185-5p expression and increased expression of CDK6 and ROR. ROR knockdown reduced H/R induced pyroptosis and inflammation, while knockdown of miR-185-5p accelerated the effect. Furthermore, miR-185-5p was negatively regulated and absorbed by ROR in HCMs. Overexpression of miR-185-5p reversed the H/R-induced cell pyroptosis and upregulation of LDH, IL-1ß, and IL-18. In HCMs, miR-185-5p was also negatively regulated and related to CDK6 expression. Moreover, overexpression of CDK6 significantly inhibited the effects of miR-185-5p mimics on the inflammatory response and pyroptosis of HCMs. Knockdown of ROR alleviated H/R-induced myocardial injury by elevating miR-185-5p and inhibiting CDK6 expression. Taken together, our results show that the ROR/miR-185-5p/CDK6 axis modulates cell pyroptosis induced by H/R and the inflammatory response of HCMs.

MicroRNA-132 regulates total protein of Nav1.1 and Nav1.2 in the hippocampus and cortex of rat with chronic cerebral hypoperfusion.

Nav1.1 and Nav1.2 are the voltage-gated sodium channel alpha subunit1 and 2, encoded by the genes of SCN1A and SCN2A. Previous studies have shown that chronic cerebral hypoperfusion (CCH) could induce neuropathological and cognitive impairment and increased total Nav1.1 and Nav1.2protein levels, yet the detailed mechanisms are not fully understood. MicroRNAs (miRNAs) are a class of small, non-coding RNAs that are involved in the regulation of dementia. miR-132 is known to play a key role in neurodegenerative disease. Here, we determined that miR-132 regulates Nav1.1 and Nav1.2 under CCH state. In this study, the expression of miR-132 was decreased in both the hippocampus and cortex of ratsfollowing CCH generated by bilateral common carotid artery occlusion (2VO). Lentiviral-mediated overexpression of miR-132 ameliorated dementia vulnerability induced by 2VO. At the molecular level, miR-132 repressed the increased protein expression of Nav1.1 and Nav1.2 in both the hippocampus and cortex induced by 2VO. MiR-132 suppressed, while AMO-miR-132 enhanced, the level of Nav1.1 and Nav1.2 in primary cultured neonatal rat neurons (NRNs) detected by both western blot analysis and immunofluorescence analysis. Results obtained by dual luciferase assay showed that overexpression of miR-132 inhibited the expression of Nav1.1 and Nav1.2 in human embryonic kidney 293 (HEK293T) cells. Additionally, binding-site mutation failed to influence Nav1.1 and Nav1.2, indicating that Nav1.1 and Nav1.2 are potential targets for miR-132. Taken together, our findings demonstrated that miR-132 protects against CCH-induced learning and memory impairments by down-regulating the expression of Nav1.1 and Nav1.2, and SCN1A and SCN2A are the target genes of miR-132.