MiR-218 promotes oxidative stress and inflammatory response by inhibiting SPRED2-mediated autophagy in HG-induced HK-2 cells.

BACKGROUND: Diabetic nephropathy (DN) is one of the most common complications of diabetes mellitus (DM). MicroRNA (miR)-218 is associated with the development of diabetes. Besides, sprouty-related EVH1 domain containing 2 (SPRED2), the downstream target of miR-218, is involved in insulin resistance and inflammation. OBJECTIVES: Since inflammation plays a key role in DN, and SPRED2 is known to facilitate cell autophagy, the present study aimed to investigate the role and molecular mechanism of miR-218 and SPRED2-mediated autophagy in high glucose (HG)-induced renal tubular epithelial cells using an in vitro model. MATERIAL AND METHODS: The HK-2 cells were cultured in 5.5 mM or 30 mM D-glucose medium. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of miR-218 and SPRED2. Western blotting was performed to calculate the levels of SPRED2, inflammatory cytokines, autophagy-related and apoptosis-related proteins. Reactive oxygen species (ROS) level was evaluated using cellular ROS assay kit, superoxide dismutase (SOD) activity was detected using SOD activity assay kit, and malondialdehyde (MDA) content was measured using lipid peroxidation. The levels of interleukin (IL)-1ß, IL-6, IL-4, and tumor necrosis factor alpha (TNF-α) were detected with enzyme-linked immunosorbent assay (ELISA). Cell apoptosis was evaluated using flow cytometry analysis. The targeting relationship between miR-218 and SPRED2 was identified with a luciferase reporter. The LC3-II expression was detected with immunofluorescence. RESULTS: The miR-218 expression was upregulated and SPRED2 expression was downregulated in HG-induced HK-2 cells. The miR-218 was proven to target SPRED2 and negatively regulate SPRED2 expression. Besides, downregulated miR-218 alleviated inflammatory response, oxidative stress and cell apoptosis, but aggravated autophagy. We also showed that downregulated SPRED2 reversed the effect of miR-218 on inflammation, cell apoptosis and autophagy in HG-induced HK-2 cells. CONCLUSIONS: The miR-218 can promote oxidative stress and inflammatory response in HG-induced renal tubular epithelial cells by inhibiting SPRED2-mediated autophagy. This study might bring novel understanding for molecular mechanism of DN.

Hyaluronic Acid Facilitates Angiogenesis of Endothelial Colony Forming Cell Combining With Mesenchymal Stem Cell via CD44/ MicroRNA-139-5p Pathway.

Stem cells and progenitor cells have been identified as potential new therapeutic options for severe limb ischemia to induce angiogenesis, and hyaluronic acid (HA) is commonly applied as a biomaterial in tissue engineering. However, the efficiency of HA combined with human umbilical cord blood-derived endothelial colony forming cells (ECFCs) and human umbilical-derived mesenchymal stem cells (MSCs) on angiogenesis is unclear. In the present study, we showed that HA promoted angiogenesis induced by MSCs-ECFCs in Matrigel plugs and promoted blood perfusion of murine ischemic muscles. Laser confocal microscopy revealed that human-derived cells grew into the host vasculature and formed connections, as shown by mouse-specific CD31+/human-specific CD31+ double staining. In vitro assays revealed that HA supported cell proliferation and migration, enhanced CD44 expression and reduced microRNA (miR)-139-5p expression. Further analysis revealed that miR-139-5p expression was negatively regulated by CD44 in ECFCs. Flow cytometry assays showed that HA increased CD31 positive cells proportion in MSC-ECFC and could be reversed by miR-139-5p mimics transfection. Moreover, the improvement of MSC-ECFC proliferation and migration induced by HA could be blocked by upregulation of miR-139-5p expression. In conclusion, HA facilitates angiogenesis of MSCs-ECFCs, and this positive effect be associated with activation of the CD44/miR-139-5p pathway, providing a promising strategy for improving severe limb ischemia.

CircularRNA circ_0071269 knockdown protects against from diabetic cardiomyopathy injury by microRNA-145/gasdermin A axis.

Circular RNAs (circRNAs) are involved in the development and progression of diabetic cardiomyopathy (DCM). However, the specific function and underlying mechanism of circ_0071269 in DCM remains unclear. In our study, mRNA and miRNA expression was detected by real-time quantitative PCR (qRT-PCR). RNase R and actinomycin D treatment were applied to test the characteristics of circ_0071269. Cell Counting Kit-8 (CCK-8) assay, lactate dehydrogenase (LDH) and enzyme-linked immunosorbent assay (ELISA) kits were performed to determine the cell viability, cell LDH content and interleukin (IL)-1ß and IL-18 levels, respectively. Cell death rate was determined by Flow cytometry, and Western blotting was for the protein expression levels. In addition, luciferase reporter and RNA pull-down assays were performed to confirm the binding relationship between miR-145 and circ_0071269 or gasdermin A (GSDMA). Echocardiography, Hematoxylin and Eosin (HE) Staining, and Immunohistochemical (IHC) Staining were performed to evaluate myocardial damage in vivo. We found that circ_0071269 was significantly overexpressed in H9c2 cells upon treatment with high glucose. Knockdown of circ_0071269 promoted cell viability and inhibited the inflammatory response, cytotoxicity, and pyroptosis of H9c2 cells in vitro. Moreover, circ_0071269 sponges miR-145 to upregulate GSDMA. A miR-145 inhibitor antagonized the effects of circ_0071269 knockdown on the cellular functions of H9c2 cells, while the effects of miR-145 were abrogated by the overexpression of GSDMA. Meanwhile, knockdown of circ_0071269 attenuated cardiac dysfunction of DM mice. Hence, circ_0071269 may promote the development of DCM through the miR-145/GSDMA axis and thus provide a novel marker for the treatment of DCM.