Cell Proliferation In Mesangial Cells Research Articles

FOXP1 inhibits high glucose-induced ECM accumulation and oxidative stress in mesangial cells

Diabetic nephropathy (DN) is a common complication of diabetes that remains the major cause of end‐stage renal disease (ESRD). Forkhead box P1 (FOXP1) is a member of FOX family involved in the progression of diabetes. However, the pathogenic role of FOXP1 in DN remains unclear. This study was aimed to explore the effects of FOXP1 on glomerular mesangial cells (MCs) in response to high glucose (HG) stimulation. We found that HG stimulation markedly inhibited the FOXP1 expression in MCs in dose-and time-dependent manner. CCK-8 assay proved that FOXP1 overexpression attenuated HG-induced cell proliferation in MCs. FOXP1 exhibited anti-oxidative activity in HG-induced MCs, as proved by the decreased production of ROS and expressions of ROS producing enzymes, NADPH oxidase (NOX) 2 and NOX4. Besides, FOXP1 suppressed the expression and secretion of extracellular matrix (ECM) proteins including collagen IV (Col IV) and fibronectin (FN). Furthermore, FOXP1 overexpression significantly prevented HG-induced activation of Akt/mTOR signaling in MCs, and Akt activator blocked FOXP1-mediated cell proliferation, ROS production and ECM accumulation in MCs. Collectively, FOXP1 prevented HG-induced proliferation, oxidative stress, and ECM accumulation in MCs via inhibiting the activation of Akt/mTOR signaling pathway. The findings suggested that FOXP1 might be a therapeutic target for the treatment of DN.

Knockdown of FOXO6 inhibits cell proliferation and ECM accumulation in glomerular mesangial cells cultured under high glucose condition.

Forkhead box O 6 (FOXO6), a FOX transcription factor, has been found to be involved in diabetes mellitus and related complications. However, the role of FOXO6 in diabetic nephropathy (DN) has not been fully understood. In the present study, we evaluated the functions of FOXO6 in high glucose (HG)-induced glomerular mesangial cells (MCs). The results showed that FOXO6 expression was significantly elevated in MCs after HG stimulation. Knockdown of FOXO6 by transfection with small interfering RNA (siRNA) targeting FOXO6 (siRNA-FOXO6) suppressed cell proliferation in MCs. The productions of extracellular matrix (ECM) components including collagen IV (Col IV) and fibronectin (FN) were markedly decreased after FOXO6 knockdown in MCs. Furthermore, knockdown of FOXO6 inhibited HG-induced activation of p38 MAPK signaling pathway in MCs. Collectively, these findings suggested that knockdown of FOXO6 inhibited cell proliferation and ECM accumulation in HG-induced MCs via inhibiting p38 MAPK signaling pathway. FOXO6 might be a beneficial therapeutic target for the prevention and treatment of DN.

SND p102 promotes extracellular matrix accumulation and cell proliferation in rat glomerular mesangial cells via the AT1R/ERK/Smad3 pathway.

SND p102 was first described as a transcriptional co-activator, and subsequently determined to be a co-regulator of Pim-1, STAT6 and STAT5. We previously reported that SND p102 expression was increased in high glucose-treated mesangial cells (MCs) and plays a role in the extracellular matrix (ECM) accumulation of MCs by regulating the activation of RAS. In this study, we further examined the roles of SND p102 in diabetic nephropathy (DN)-induced glomerulosclerosis. Rats were injected with STZ (50 mg/kg, ip) to induce diabetes. MCs or isolated glomeruli were cultured in normal glucose (NG, 5.5 mmol/L)- or high glucose (HG, 25 mmol/L)-containing DMEM. We found that SND p102 expression was significantly increased in the diabetic kidneys, as well as in HG-treated isolated glomeruli and MCs. In addition, HG treatment induced significant fibrotic changes in MCs evidenced by enhanced protein expression of TGF-β, fbronectin and collagen IV, and significantly increased the proliferation of MCs. We further revealed that overexpression of SND p102 significantly increased the protein expression of angiotensin II (Ang II) type 1 receptor (AT1R) in MCs by increasing its mRNA levels via directly targeting the AT1R 3'-UTR, which resulted in activation of the ERK/Smad3 signaling and subsequently promoted the up-regulation of fbronectin, collagen IV, and TGF-β in MCs, as well as the cell proliferation. These results demonstrate that SND p102 is a key regulator of AT1R-mediating ECM synthesis and cell proliferation in MCs. Thus, small molecule inhibitors of SND p102 may be a novel therapeutic strategy for DN.

The Long Noncoding RNA 150Rik Promotes Mesangial Cell Proliferation via miR-451/IGF1R/p38 MAPK Signaling in Diabetic Nephropathy

Background/Aims: Diabetic nephropathy (DN) as the primary cause of end-stage kidney disease is a common complication of diabetes. However, the initiating molecular events triggering DN are unknown. Recently, long noncoding RNAs (lncRNAs) have been shown to play important roles in DN. Methods: The expression level of lncRNA 1500026H17Rik (150Rik for short) was measured by qRT-PCR (quantitative real-time PCR). Cell proliferation ability was detected by 5-Ethynyl-2’-deoxyuridine (EdU). The relationship between 150Rik and microRNA 451 (miR-451) was examined by luciferase assay and RNA immunoprecipitation (RIP) assay. Finally, the effect of 150Rik on cell proliferation through the miR-451/insulin-like growth factor 1 receptor (IGF1R)/mitogen-activated protein kinases (p38MAPK) pathway was detected by EdU, flow cytometry analysis, western blot. Results: We found that 150Rik, an evolutionarily conserved lncRNA, was significantly upregulated in renal tissue of db/db DN mice and in mesangial cells (MCs) cultured under a high glucose condition. Further, overexpression or knockdown of 150Rik was found to regulate cell proliferation in MCs. Moreover, 150Rik was found to interact with miR-451 in both a direct and argonaute-2 (Ago2)-dependent manner. Results also revealed that overexpression of 150Rik inhibited cell proliferation through the miR-451/IGF1R/p38MAPK pathway in MCs under the high glucose condition, while knockdown of 150Rik increased cell proliferation via the miR-451/IGF1R/p38MAPK pathway. Conclusion: Taken together, these results provide new insight into the association between 150Rik and the miR-451/IGF1R/p38MAPK signaling pathway during DN progression.

LincRNA-Gm4419 knockdown ameliorates NF-\u03baB/NLRP3 inflammasome-mediated inflammation in diabetic nephropathy

Diabetic nephropathy (DN) as the primary cause of end-stage kidney disease is a common complication of diabetes. Recent researches have shown the activation of nuclear factor kappa light-chain enhancer of activated B cells (NF-κB) and NACHT, LRR and PYD domain-containing protein 3 (NLRP3) inflammasome are associated with inflammation in the progression of DN, but the exact mechanism is unclear. Long noncoding RNAs (lncRNAs) have roles in the development of many diseases including DN. However, the relationship between lncRNAs and inflammation in DN remains largely unknown. Our previous study has revealed that 14 lncRNAs are abnormally expressed in DN by RNA sequencing and real-time quantitative PCR (qRT-PCR) in the renal tissues of db/db DN mice. In this study, these lncRNAs were verified their expressions by qRT-PCR in mesangial cells (MCs) cultured under high- and low-glucose conditions. Twelve lncRNAs displayed the same expressional tendencies in both renal tissues and MCs. In particular, long intergenic noncoding RNA (lincRNA)-Gm4419 was the only one associating with NF-κB among these 12 lncRNAs by bioinformatics methods. Moreover, Gm4419 knockdown could obviously inhibit the expressions of pro-inflammatory cytokines and renal fibrosis biomarkers, and reduce cell proliferation in MCs under high-glucose condition, whereas overexpression of Gm4419 could increase the inflammation, fibrosis and cell proliferation in MCs under low-glucose condition. Interestingly, our results showed that Gm4419 could activate the NF-κB pathway by directly interacting with p50, the subunit of NF-κB. In addition, we found that p50 could interact with NLRP3 inflammasome in MCs. In conclusion, our findings suggest lincRNA-Gm4419 may participate in the inflammation, fibrosis and proliferation in MCs under high-glucose condition through NF-κB/NLRP3 inflammasome signaling pathway, and may provide new insights into the regulation of Gm4419 during the progression of DN.