Diabetic nephropathy (DN) is one of the most significant complications of diabetes and is the primary cause of end-stage kidney disease. Cumulating evidence has shown that renal inflammation plays a role in the development and progression of DN, but the exact cellular mechanisms are unclear. Irregular expression of long non-coding RNAs (lncRNAs) is present in many diseases, including DN. However, the relationship between lncRNAs and inflammation in DN is unclear. In this study, we identified differentially expressed lncRNAs in DN using RNA-sequencing. Among these lncRNAs, we identified seven DN-related lncRNAs in vivo and in vitro using quantitative real-time PCR. One lncRNA in particular, Rpph1 (ribonuclease P RNA component H1), exhibited significantly increased expression. Further, over-expression or knockdown of Rpph1 was found to regulate cell proliferation and the expression of inflammatory cytokines in mesangial cells (MCs). The results revealed that Rpph1 directly interacts with the DN-related factor galectin-3 (Gal-3). Further, over-expression of Rpph1 promoted inflammation and cell proliferation through the Gal-3/Mek/Erk signaling pathway in MCs under low glucose conditions, while knockdown of Rpph1 inhibited inflammation and cell proliferation through the Gal-3/Mek/Erk pathway in MCs under high glucose conditions. These results provide new insight into the association between Rpph1 and the Gal-3/Mek/Erk signaling pathway during DN progression.

Evidence has shown that long noncoding RNAs (IncRNAs) in the competing endogenous RNA (ceRNA) network are involved in various diseases. However, there is a lack of studies of the ceRNA network in diabetic nephropathy (DN). In this study, we investigated the effect of IncRNAs on mesangial cell (MC) proliferation in DN‐related ceRNA networks. Differences in IncRNA and mRNA expression between DN and normal mouse kidney tissues were detected with RNA‐seq, and DN‐related IncRNA/mRNA/microRNA (miRNA) ceRNA networks were constructed by R3.4.3. Computational analysis was performed, and expression and interactions between the topological RNAs were detected by bioinformatics methods, real‐time quantitative PCR (qPCR), and luciferase assay. Cell proliferation ability was measured by 5‐ethynyl‐2′‐deoxyuridine (EdU) in MCs cultured under high‐ or low‐glucose conditions. Moreover, the effect of the topological key IncRNA histocompatibility 2 K region locus 2 (H2k2) H2k2 on MC proliferation via the miRNA (miR)‐449a/b/triplet motif 11 (Trim11)/Mek signaling pathway was examined by EdU, flow cytometry analysis, and Western blot. In total, 153 IncRNAs, 428 mRNAs, and 2242 interactions were included in the constructed DN‐related ceRNA network. There were 15 RNAs in the top 5% of degree and betweenness. The expression of IncRNA H2k2 and mRNA Trim11 in MCs was increased in DN, which is consistent with the results of RNA‐seq and real‐time qPCR in vivo and in vitro. miR‐449a and miR‐449b, which were down‐regulated in MCs cultured with high glucose, were selected for further analysis. The results of real‐time qPCR and luciferase assay revealed the IncRNA H2k2‐miR‐449a/b‐Trim11 interaction in MCs. In addition, the data showed that H2k2 regulates MC proliferation via the miR‐449ab/Trim11/Mek signaling pathway. Taken together, these results provide new insight into the association between the topological key IncRNA H2k2 in the DN‐related ceRNA network and the miR‐449a/b/Trim11/Mek signaling pathway during MC proliferation in DN.—Chen, W., Peng, R., Sun, Y., Liu, H., Zhang, L., Peng, H., Zhang, Z. The topological key IncRNA H2k2 from the ceRNA network promotes mesangial cell proliferation in diabetic nephropathy via the miR‐449a/b/Trim11/Mek signaling pathway. FASEB J. 33, 11492–11506 (2019). http://www.fasebj.org

Serum human hedgehog-interacting protein (HHIP) concentration is associated with diabetes. However, the relationship between HHIP and polycystic ovary syndrome (PCOS) or abnormal sex hormones remains unknown. This study was an observational cross-sectional study, with additional short-term intervention studies and follow-up studies. Bioinformatics analysis was performed to explore the association of PCOS with metabolic-related genes and signaling pathways. OGTT and EHC were performed on all participants. Lipid infusion, cold exposure, and 45-min treadmill test were performed on all healthy women. A total of 137 women with PCOS were treated with metformin, GLP-1RA, or TZDs for 24 weeks. Serum HHIP levels were higher in insulin resistance (IR) and PCOS women. Circulating HHIP levels were significantly correlated with adiponectin (Adipoq) levels, obesity, IR, and metabolic indicators. A correlation presented between HHIP and DHEA-S, FAI, SHBG, and FSH. Serum HHIP levels were significantly elevated by oral glucose challenge in healthy women, but not affected by EHC. Lipid infusion decreased serum HHIP levels, while cold exposure increased HHIP levels in healthy women. GLP-1RA and TZD treatment reduced serum HHIP levels in PCOS women, while metformin treatment did not affect HHIP levels. HHIP may be a useful biomarker and novel drug target for PCOS and IR individuals.