Deletion of miRNAs in bone marrow prevents streptozotocin-induced murine autoimmune diabetes but deletion of miR-155 does not

MicroRNA-6884-5p Regulates the Proliferation, Invasion, and EMT of Gastric Cancer Cells by Directly Targeting S100A16

S100 binding protein A16 (S100A16) expression levels are closely associated with microRNA (miRNA) processing. Higher levels of S100A16 are reported during the progression of many cancers. Our study mainly explored the interaction between S100A16 and miR-6884-5p in gastric cancer (GC). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the level of S100A16 and miR-6884-5p in GC tissues and cell lines. The si-S100A16, pcDNA-S100A16, miR-6884-5p mimic or inhibitor was transfected into GC cells, and the effects of S100A16 and miR-6884-5p on the proliferation, invasion, and epithelial-mesenchymal transition (EMT) were explored by qRT-PCR and Western blot assays. Luciferase assays were performed to validate S100A16 as an miR-6884-5p target in GC cells. In our study, we found that the level of miR-6884-5p was significantly decreased and the expression of S100A16 was significantly increased in GC tissues and cell lines. There was a close association between these changes. Knockdown of S100A16 significantly inhibited the proliferation, invasion, and EMT of GC cells. The bioinformatics analysis predicted that S100A16 is a potential target gene of miR-6884-5p, and the luciferase reporter assay confirmed that miR-6884-5p could directly target S100A16. Introduction of miR-6884-5p to GC cells had similar effects to S100A16 silencing. Overexpression of S100A16 in GC cells partially reversed the inhibitory effects of the miR-6884-5p mimic. miR-6884-5p inhibited the proliferation, invasion, and EMT of GC cells by directly decreasing S100A16 expression.

miR-155 is dispensable in monosodium urate-induced gouty inflammation in mice

BACKGROUND

The findings of a previous study by Jin et al. have shown that microRNA (miR)-155 was upregulated in patients with acute gouty arthritis and enhanced the proinflammatory cytokines. There is no direct evidence to support that miR-155 is indeed involved in monosodium urate (MSU)-induced inflammatory responses in vivo. The aim of this study was to investigate the role of miR-155 knock-out (KO) or knock-in (KI) mice in MSU-induced animal models to mimic acute gout.

METHODS

MiR-155 expression in cultured bone marrow-derived macrophages (BMDMs) from miR-155 KO, miR-155 KI, and wild-type (WT) mice treated with MSU crystals in vitro was detected by real-time quantitative polymerase chain reaction (qPCR). MiR-155 KO and WT mice were used to induce an acute gouty inflammatory response with MSU crystals including models of foot pad inflammation, ankle arthritis, air pouch inflammation, and peritonitis. Furthermore, the proinflammatory interleukin (IL)-1β levels in lavage fluids from air pouch and peritoneal cavity models were measured by enzyme-linked immunosorbent assay (ELISA), and tumor necrosis factor (TNF)-α production from BMDMs of miR-155 KI mice treated with MSU were measured by flow cytometry.

RESULTS

MiR-155 expression was quickly upregulated in BMDMs from WT mice following MSU treatment in vitro. In comparison with WT mice in vivo, the swelling index of miR-155 KO mice showed no significant difference in the murine foot pad and ankle arthritis models for the indicated different time points. There were similar changes in total cell numbers of lavage fluids in the air pouch and peritoneal cavity models between miR-155 KO and WT mice following MSU crystal injection. Moreover, the IL-1β levels of lavage fluids in the air pouch and peritonitis models from miR-155 KO mice were almost the same as those from WT mice. TNF-α levels were comparable from BMDMs treated with MSU crystals in vitro between miR-155 KI mice and WT mice.

CONCLUSIONS

MiR-155 is dispensable in MSU-induced gouty inflammation in mice. Deletion of miR-155 might not be an effective therapeutic approach to relieve the inflammation in acute gout.

microRNA-340 influences cell proliferation, apoptosis and invasion by targeting NF-κB1 in gastric cancer

Gastric cancer is a serious threat to human health, and its pathogenesis may be regulated by a variety of mRNAs. Abnormal expression of microRNA-340 has been frequently reported in many malignant neoplasms, while the molecular mechanism of miR-340 has not been explored in gastric cancer. In this study, the mRNA level of miR-340 was determined by real-time PCR in GC cell lines. The miR-340 mimic was transiently transfected into GC cells by using Lipofectamine™ 2000 reagent. The BrdU-ELISA results showed that introduction of miR-340 inhibited cell proliferation. It was demonstrated that miR-340 mimic arrested cell cycle progression and promoted apoptosis of MKN-45 and BGC-823 cells. In addition, the overexpression of miR-340 could inhibit invasion and EMT of MKN-45 and BGC-823 cells. The expression of NF-κB1 was evidently reduced by up-regulation of miR-340. Luciferase reporter assay further confirmed that miR-340 could directly target the 3'UTR of NF-κB1. Moreover, overexpression of NF-κB1 transfected with miR-340 mimic partially reversed the inhibitory of miR-340 mimic in MKN-45 and BGC-823 cells. In conclusion, miR-340 induced cell apoptosis and inhibited invasion by down-regulation of NF-κB1, which might be a potential target in treatment and prevention of gastric cancer.

High glucose increases LPS-induced DC apoptosis through modulation of ERK1/2, AKT and Bax/Bcl-2

Background

This study investigates the effect of glucose on the LPS-induced apoptosis of dendritic cells in the intestinal tract of mice and the dendritic cell line DC2.4.

Methods

Flow cytometry was used to detect dendritic cell apoptosis both in vivo and in vitro. Hoechst 33258 staining was used to detect the morphological changes characteristic of apoptotic nuclei. Expression of apoptosis related proteins was investigated by western blot analysis and immunohistochemistry.

Results

Pretreatment with a high concentration of glucose increased apoptosis of LPS-treated dendritic cells both in vivo and in vitro at 24 h. No effect was evident at the earlier time points of 15 min and 6 h in vitro. Furthermore, at 24 hours the expression of the survival proteins AKT, ERK and Bcl-2 was decreased, while the expression of the proapoptotic protein Bax was increased. AKT, ERK, Bcl-2 and Bax were mainly located in the cytoplasm by immunohistochemistry.

Conclusions

These results suggest that high glucose concentrations might prime dendritic cells for apoptosis induced by LPS in the intestinal tract through upregulating the expression of Bax and downregulating the expression of AKT, ERK and Bcl-2. Therefore, this study may give clues to understanding the immunological mechanism behind gastrointestinal complications in diabetes mellitus.