Super Carbonate Apatite-miR-497a-5p Complex Is a Promising Therapeutic Option against Inflammatory Bowel Disease.

The incidence of inflammatory bowel disease (IBD) is increasing worldwide. It is reported that TGF-ß/Smad signal pathway is inactivated in patients with Crohn's disease by overexpression of Smad 7. With expectation of multiple molecular targeting by microRNAs (miRNAs), we currently attempted to identify certain miRNAs that activate TGF-ß/Smad signal pathway and aimed to prove in vivo therapeutic efficacy in mouse model. Through Smad binding element (SBE) reporter assays, we focused on miR-497a-5p. This miRNA is common between mouse and human species and enhanced the activity of TGF-ß/Smad signal pathway, decreased Smad 7 and/or increased phosphorylated Smad 3 expression in non-tumor cell line HEK293, colorectal cancer cell line HCT116 and mouse macrophage J774a.1 cells. MiR-497a-5p also suppressed the production of inflammatory cytokines TNF-α, IL-12p40, a subunit of IL-23, and IL-6 when J774a.1 cells were stimulated by lipopolysaccharides (LPS). In a long-term therapeutic model for mouse dextran sodium sulfate (DSS)-induced colitis, systemic delivery of miR-497a-5p load on super carbonate apatite (sCA) nanoparticle as a vehicle restored epithelial structure of the colonic mucosa and suppressed bowel inflammation compared with negative control miRNA treatment. Our data suggest that sCA-miR-497a-5p may potentially have a therapeutic ability against IBD although further investigation is essential.

LncRNA SNHG14/miR-497a-5p/BACE1 axis modulates obesity-induced adipocyte inflammation and endoplasmic reticulum stress.

Obesity is a metabolic disease with excess weight. LncRNA SNHG14 is abnormally expressed in numerous diseases. This research aimed to enucleate the lncRNA SNHG14 role in obesity. Adipocytes were treated with free fatty acid (FFA) to establish an in vitro model for obesity. Mice were fed a high-fat diet to construct an in vivo model. Gene levels were determined using quantitative real-time PCR (RT-PCR). The protein level was checked by western blot. The lncRNA SNHG14 role in obesity was assessed using western blot and enzyme-linked immunosorbent assay. The mechanism was estimated by Starbase, dual-luciferase reporter gene assay, and RNA pull-down. LncRNA SNHG14 function in obesity was estimated using mouse xenograft models, RT-PCR, western blot, and enzyme-linked immunosorbent assay. LncRNA SNHG14 and BACE1 levels were increased, but the miR-497a-5p level was decreased in FFA-induced adipocytes. Interference with lncRNA SNHG14 reduced endoplasmic reticulum (ER) stress-related molecules GRP78 and CHOP expressions in FFA-induced adipocytes, and decreased IL-1ß, IL-6, and TNF-α expressions, indicating that lncRNA SNHG14 knockdown mitigated FFA-induced ER stress and inflammation in adipocytes. Mechanistically, lncRNA SNHG14 combined with miR-497a-5p, and miR-497a-5p targeted BACE1. Meanwhile, lncRNA SNHG14 knockdown reduced levels of GRP78, CHOP, IL-1ß, IL-6, and TNF-α, while cotransfection with anti-miR-497a-5p or pcDNA-BACE1 abolished these trends. Rescue assays illustrated that lncRNA SNHG14 knockdown relieved FFA-induced adipocyte ER stress and inflammation through miR-497a-5p/BACE1. Meanwhile, lncRNA SNHG14 knockdown restrained adipose inflammation and ER stress caused by obesity in vivo. LncRNA SNHG14 mediated obesity-induced adipose inflammation and ER stress through miR-497a-5p/BACE1.

Circ-Bnc2 alleviates neuroinflammation in LPS-stimulated microglial cells to inhibit neuron cell apoptosis through regulating miR-497a-5p/HECTD1 axis.

BACKGROUND: Neuroinflammation caused by microglia cells activation and the apoptosis of neuron cells are associated with the occurrence of depression. Circ-Bnc2 has been shown to be significantly downregulated in depression mice, but its role in the progression of depression remains unclear. METHODS: Lipopolysaccharide (LPS) was used to treat BV2 microglial cells to induce neuroinflammation. The expression of circ-Bnc2, microRNA (miR)-497a-5p, and HECT domain E3 ubiquitin protein ligase 1 (HECTD1) was measured by quantitative real-time PCR. The protein levels of neuroinflammation markers, apoptosis markers, and HECTD1 were determined by western blot analysis. ELISA assay was used to examine the concentrations of inflammatory factors. After HT22 cells were cultured with the conditioned medium of LPS-induced BV2 cells, the proliferation and apoptosis of HT22 cells were assessed by cell counting kit 8 assay, EdU assay, and flow cytometry. In addition, the interaction between miR-497a-5p and circ-Bnc2 or HECTD1 was confirmed by dual-luciferase reporter assay, RIP assay, and RNA pull-down assay. RESULTS: Our data showed that circ-Bnc2 was lowly expressed in LPS-induced BV2 cells. Function experiments suggested that circ-Bnc2 could inhibit LPS-induced neuroinflammation in BV2 cells to repress HT22 cell apoptosis and promote proliferation. Circ-Bnc2 could sponge miR-497a-5p, and the neuroprotective function of circ-Bnc2 could be reversed by miR-497a-5p overexpression. Additionally, miR-497a-5p could target HECTD1. miR-497a-5p inhibitor could alleviate LPS-induced neuroinflammation in BV2 cells and reduce HT22 cell apoptosis, which also could be reversed by HECTD1 knockdown. Moreover, circ-Bnc2 had a positive regulation on HECTD1 expression by sponging miR-497a-5p. CONCLUSION: In summary, our results confirmed that circ-Bnc2 could inhibit neuroinflammation and neuron cell apoptosis by regulating miR-497a-5p/HECTD1 axis, suggesting that circ-Bnc2 might be a potential target for depression treatment.

CircDYM ameliorates CUMS mice depressive-like behavior and inhibits hippocampal neurons injury via miR-497a-5p/NR3C1 axis.

BACKGROUND: Depression is an important mental disease that threatens human physical and mental health. Circular RNA (circRNA) has been confirmed to be involved in the regulation of depression progression, but the role and mechanism of circDYM in depression progression need to be further explored. METHODS: Chronic unpredictable mild stress (CUMS) mice model was constructed to assess mice depressive-like behavior using novelty-suppressed feeding test, sucrose preference test, social interaction test, and forced swimming test. The expression of circDYM, microRNA (miR)-497a-5p and glucocorticoid receptor (NR3C1) was measured by quantitative real-time PCR. The protein levels of NR3C1 and apoptosis markers were analyzed by western blot analysis. Hippocampal neurons viability, apoptosis and inflammation were detected by cell counting kit 8 assay, flow cytometry and ELISA assay. Furthermore, RNA interaction was confirmed by dual-luciferase reporter assay, RIP assay and RNA pull-down assay. RESULTS: Our study showed that circDYM and NR3C1 were downregulated and miR-497a-5p was upregulated in the hippocampus tissues of CUMS mice. Overexpressed circDYM alleviated CUMS mice depressive-like behavior and repressed hippocampal neurons injury. In terms of mechanism, circDYM could upregulate NR3C1 by sponging miR-497a-5p. MiR-497a-5p overexpression reversed the regulation of circDYM on CUMS mice depressive-like behavior and hippocampal neurons injury. In addition, the function of miR-497a-5p overexpression on CUMS mice depressive-like behavior and hippocampal neurons injury also could be reversed by overexpressing NR3C1. CONCLUSION: In summary, our study confirmed that circDYM could relieve the depressive-like behavior in CUMS mice and hippocampal neurons injury through miR-497a-5p/NR3C1 pathway. These data confirmed that circDYM had an anti-depressive function, which might be a potential target for depression treatment.

Metformin inhibits development of diabetic retinopathy through microRNA-497a-5p.

Metformin is an AMP-activated protein kinase activator that is widely prescribed for treating type 2 diabetes. Recently, metformin was reported to slow down the development and alleviate the severity of diabetic retinopathy (DR). However, the underlying mechanisms remain unclear. Here, we used an alloxan-induced diabetes mouse model to study the effects of metformin on the development of DR as well as the mechanisms. We found that DR was induced in alloxan-treated mice 10 weeks after alloxan treatment, and treatment of metformin did not prevent the occurrence of alloxan-induced diabetes. However, metformin significantly alleviated the severity of DR, seemingly through attenuating the retina neovascularization. Moreover, the total vascular endothelial cell growth factor A (VEGF-A) mRNA in mouse eyes was not altered by metformin, but the protein levels was decreased. Further analysis showed that metformin may inhibit the VEGF-A protein translation through inducing a VEGF-A-targeting microRNA, microRNA-497a-5p, resulting in reduced retina neovascularization. Thus, our study suggests a previously unappreciated role of metformin in the prevention of development of DR.