Elevated hsa‐miR‐590‐3p expression down‐regulates HMGB2 expression and contributes to the severity of IgA nephropathy

Peripheral blood mononuclear cells (PBMCs) play important roles in the pathogenesis of IgA nephropathy (IgAN). Our study aimed to provide a deep understanding of IgAN and focused on the dysregulation of hsa‐miR‐590‐3p and its target gene HMGB2 in PBMCs. Three gene expression profile datasets (GSE14795, GSE73953 and GSE25590) were downloaded from the GEO database. The DEGs (differentially expressed genes)‐miRNA network that was associated with IgAN was constructed by Cytoscape, and HMGB2 and hsa‐miR‐590‐3p were selected for further exploration. The dual‐luciferase reporter system was utilized to verify their interaction. Then, the expression levels of HMGB2 and hsa‐miR‐590‐3p in PBMCs were detected by qPCR in another cohort, and the correlation of their expression levels with the clinical pathological manifestations and serum Gd‐IgA1(galactose‐deficient IgA1) levels was also investigated. HMGB2 was identified as the target gene of hsa‐miR‐590‐3p. Furtherly, the elderly patients had higher HMGB2 expression levels than the expression levels of the younger patients. As the serum creatinine, serum BUN levels increased, the expression of HMGB2 decreased; Besides, the HMGB2 expression was positively correlated with serum complement 3(C3) levels, and it also had a negative correlation with the diastolic blood pressure, but not reach statistical significance. What is more, both hsa‐miR‐590‐3p and HMGB2 expression had a slight correlation tendency with serum Gd‐IgA1 levels in the whole population. In conclusion, HMGB2, the target gene of hsa‐miR‐590‐3p, was identified to correlate with the severity of IgAN, and this provides more clues for the pathogenesis of IgAN.     

Loss of PPM1F expression predicts tumour recurrence and is negatively regulated by miR‐590‐3p in gastric cancer

Objectives

MicroRNAs (miRNAs) as small non‐coding RNA molecules act by negatively regulating their target genes. Recent studies have shown that protein phosphatase Mg2+/Mn2+‐dependent 1F (PPM1F) plays a critical role in cancer metastasis. But, the regulation mechanisms of PPM1F by miRNAs in gastric cancer (GC) remain undefined.

Methods

The correlation of PPM1F or miR‐590‐3p (miR‐590) expression with clinicopathological features and prognosis of the patients with GC was analysed by TCGA RNA‐sequencing data. The miRNAs that target PPM1F gene were identified by bioinformatics and Spearman correlation analysis, and the binding site between miR‐590 and PPM1F 3′UTR was confirmed by dual luciferase assay. MTT and Transwell assays were conducted to evaluate the effects of miR‐590 or (and) PPM1F on cell proliferation and invasion.

Results

We found that PPM1F expression was downregulated in GC tissues and cell lines and was correlated with tumour recurrence in patients with GC. The decreased expression of PPM1F was attributed to the dysregulation of miR‐590 expression rather than its genetic or epigenetic alterations. Overexpression of miR‐590 promoted cell proliferation and invasion capability of GC cells, while knockdown of miR‐590 reversed these effects. Moreover, PPM1F was validated as a direct target of miR‐590 and counteracted the tumour‐promoting effects caused by miR‐590. The expression of miR‐590 presented the negative correlation with PPM1F expression and acted as an independent prognostic factor for tumour recurrence in patients with GC.

Conclusion

PPM1F may function as a suppressive factor and is negatively regulated by miR‐590 in GC.

     

LncRNA Gm2044 promotes 17β‐estradiol synthesis in mpGCs by acting as miR‐138‐5p sponge

Long noncoding RNAs (lncRNAs) have been demonstrated to play vital roles in mammalian reproduction. Our previous research revealed that lncRNA Gm2044 is highly expressed in mouse spermatocytes and regulates male germ cell function. The gene annotation database BioGPS shows that Gm2044 is not only highly expressed in testicular tissue but also in ovarian tissue, which suggests that Gm2044 may be involved in female reproductive development. In this study, we confirmed that lncRNA Gm2044 promotes 17β‐estradiol synthesis in mouse pre‐antral follicular granulosa cells (mpGCs). Furthermore, bioinformatics methods, western blot, and the luciferase assay proved that Gm2044 functions as a miR‐138‐5p sponge to inhibit the direct target of miR‐138‐5p, Nr5a1, which enhances 17β‐estradiol synthesis through cyp19a1 activation. Taken together, our results provide an insight into the mechanistic roles of lncRNA Gm2044 for 17β‐estradiol synthesis by acting as competing‐endogenous RNAs to modulate the function of mpGCs. Studying the potential lncRNAs, which regulate estradiol release, will be beneficial for the diagnosis and treatment of steroid hormone‐related disease.     

Upregulation of miR‐874‐3p and miR‐874‐5p inhibits epithelial ovarian cancer malignancy via SIK2

Based on miR‐874 expression levels in the GSE47841 microarray, we hypothesized that the mature products of miR‐874, miR‐874‐3p, or miR‐874‐5p, would inhibit epithelial ovarian cancer (EOC) cell proliferation, metastasis, and chemoresistance. We first examined miR‐874‐3p and miR‐874‐5p expression levels in primary EOC tumor tissue samples and found that they were significantly decreased. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) cell proliferation and transwell assays revealed that miR‐874‐3p and miR‐874‐5p significantly inhibit EOC cell proliferation, migration, and invasion. Then, using MTT and soft agar assays of paclitaxel‐treated Caov3 and SKOV3 cells transfected with miR‐874‐3p and miR‐874‐5p, we found that miR‐874‐3p and miR‐874‐5p enhance EOC cell chemosensitivity. We then confirmed that serine/threonine‐protein kinase 2 (SIK2) was a target gene of miR‐874‐3p and miR‐874‐5p. Overall, the results of this study indicate that SIK2 expression can serve as a prognostic biomarker for EOC and that miR‐874‐3p and miR‐874‐5p have the potential to enhance clinical treatment of EOC.     

Epigallocatechin‐3‐O‐gallate up‐regulates microRNA‐199a‐3p expression by down‐regulating the expression of cyclooxygenase‐2 in stimulated human osteoarthritis chondrocytes

Osteoarthritis (OA) is a most common form of arthritis worldwide leading to significant disability. MicroRNAs (miRNAs) are non‐coding RNAs involved in various aspects of cartilage development, homoeostasis and pathology. Several miRNAs have been identified which have shown to regulate expression of target genes relevant to OA pathogenesis such as matrix metalloproteinase (MMP)‐13, cyclooxygenase (COX)‐2, etc. Epigallocatechin‐3‐O‐gallate (EGCG), the most abundant and active polyphenol in green tea, has been reported to have anti‐arthritic effects, however, the role of EGCG in the regulation of miRNAs has not been investigated in OA. Here, we showed that EGCG inhibits COX‐2 mRNA/protein expression or prostaglandin E₂ (PGE₂) production via up‐regulating microRNA hsa‐miR‐199a‐3p expression in interleukin (IL)‐1β‐stimulated human OA chondrocytes. This negative co‐regulation of hsa‐miR‐199a‐3p and COX‐2 by EGCG was confirmed by transfection of OA chondrocytes with anti‐miR‐199a‐3p. Transfection of OA chondrocytes with anti‐miR‐199a‐3p significantly enhanced COX‐2 expression and PGE₂ production (P < 0.001), while EGCG treatment significantly inhibited anti‐miR‐199a‐3p transfection‐induced COX‐2 expression or PGE₂ production in a dose‐dependent manner. These results were further re‐validated by co‐treatment of these transfection OA chondrocytes with IL‐1β and EGCG. EGCG treatment consistently up‐regulated the IL‐1β‐decreased hsa‐miR‐199a‐3p expression (P < 0.05) and significantly inhibited the IL‐1β‐induced COX‐2 expression/PGE₂ production (P < 0.05) in OA chondrocytes transfected with anti‐hsa‐miR‐199a‐3p. Taken together, these results clearly indicate that EGCG inhibits COX‐2 expression/PGE₂ production via up‐regulation of hsa‐miR‐199a‐3p expression. These novel pharmacological actions of EGCG on IL‐1β‐stimulated human OA chondrocytes provide new suggestions that EGCG or EGCG‐derived compounds inhibit cartilage breakdown or pain by up‐regulating the expression of microRNAs in human chondrocytes.