FGF21 overexpression alleviates VSMC senescence in diabetic mice by modulating the SYK-NLRP3 inflammasome-PPARγ-catalase pathway.

Diabetes accelerates vascular senescence, which is the basis for atherosclerosis and stiffness. The activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome and oxidative stress are closely associated with progressive senescence in vascular smooth muscle cells (VSMCs). The vascular protective effect of FGF21 has gradually gained increasing attention, but its role in diabetes-induced vascular senescence needs further investigation. In this study, diabetic mice and primary VSMCs are transfected with an FGF21 activation plasmid and treated with a peroxisome proliferator-activated receptor γ (PPARγ) agonist (rosiglitazone), an NLRP3 inhibitor (MCC950), and a spleen tyrosine kinase (SYK)-specific inhibitor, R406, to detect senescence-associated markers. We find that FGF21 overexpression significantly restores the level of catalase (CAT), vascular relaxation, inhibits the intensity of ROSgreen fluorescence and p21 immunofluorescence, and reduces the area of SA-ß-gal staining and collagen deposition in the aortas of diabetic mice. FGF21 overexpression restores CAT, inhibits the expression of p21, and limits the area of SA-ß-gal staining in VSMCs under high glucose conditions. Mechanistically, FGF21 inhibits SYK phosphorylation, the production of the NLRP3 dimer, the expression of NLRP3, and the colocalization of NLRP3 with PYCARD (ASC), as well as NLRP3 with caspase-1, to reverse the cleavage of PPARγ, preserve CAT levels, suppress ROSgreen density, and reduce the expression of p21 in VSMCs under high glucose conditions. Our results suggest that FGF21 alleviates vascular senescence by regulating the SYK-NLRP3 inflammasome-PPARγ-catalase pathway in diabetic mice.

Sodium tanshinone IIA sulfonate ameliorates neointima by protecting endothelial progenitor cells in diabetic mice.

BACKGROUND: Endothelial progenitor cells (EPCs) transplantation is one of the effective therapies for neointima associated with endothelial injury. Diabetes impairs the function of EPCs and cumbers neointima prevention of EPC transplantation with an ambiguous mechanism. Sodium Tanshinone IIA Sulfonate (STS) is an endothelium-protective drug but whether STS protects EPCs in diabetes is still unknown. METHODS: EPCs were treated with High Glucose (HG), STS, and Nucleotide-binding Domain-(NOD) like Receptor 3 (NLRP3), caspase-1, the Receptor of Advanced Glycation End products (AGEs) (RAGE) inhibitors, Thioredoxin-Interacting Protein (TXNIP) siRNA, and EPC proliferation, differentiation functions, and senescence were detected. The treated EPCs were transplanted into db/db mice with the wire-injured Common Carotid Artery (CCA), and the CD31 expression and neointima were detected in the CCA inner wall. RESULTS: We found that STS inhibited HG-induced expression of NLRP3, the production of active caspase-1 (p20) and mature IL-1ß, the expression of catalase (CAT) cleavage, γ-H2AX, and p21 in EPCs. STS restored the expression of Ki67, CD31 and von Willebrand Factor (vWF) in EPCs; AGEs were found in the HG-treated EPCs supernatant, and RAGE blocking inhibited the expression of TXNIP and the production of p20, which was mimicked by STS. STS recovered the expression of CD31 in the wire-injured CCA inner wall and the prevention of neointima in diabetic mice with EPCs transplantation. CONCLUSION: STS inhibits the aggravated neointima hyperplasia by protecting the proliferation and differentiation functions of EPC and inhibiting EPC senescence in diabetic mice. The mechanism is related to the preservation of CAT activity by inhibiting the RAGE-TXNIP-NLRP3 inflammasome pathway.

miR-29c is downregulated in renal interstitial fibrosis in humans and rats and restored by HIF-α activation.

Treatment with L-mimosine, which activates hypoxia-inducible factor-α (HIF-α), attenuates renal tubulointerstitial injury and improves renal function in a rat remnant kidney model. The miR-29 family of microRNAs directly targets a large number of extracellular matrix genes and reduces renal interstitial fibrosis. We analyzed microRNA expression profiles in rat remnant kidneys with or without treatment with L-mimosine. The expression of miR-29c was downregulated in rat remnant kidneys compared with sham control and significantly restored by the L-mimosine treatment. In cultured human kidney epithelial HK2 cells, cobalt chloride activated HIF-α and upregulated miR-29c expression. The upregulation of miR-29c expression was significantly attenuated by knockdown of HIF-1α or HIF-2α. Downregulation of miR-29c was associated with significant increases in interstitial fibrosis, collagen type II α1 (COL2A1) protein, and tropomyosin 1α (TPM1) protein in rat remnant kidneys and in kidneys from IgA nephropathy patients. The increases in rat remnant kidneys were attenuated by the L-mimosine treatment. COL2A1 and TPM1 were confirmed to be new, direct targets of miR-29c. In conclusion, miR-29c, an antifibrotic microRNA, is upregulated by HIF-α activation. MiR-29c is downregulated in renal interstitial fibrosis in humans and rats and restored by activation of HIF-α that attenuates fibrosis.

[The prevalence and risk factors of kidney disease in type 2 diabetic patients in rural Shanghai].

OBJECTIVE: To identify the prevalence and etiology of kidney disease and the related risk factors in type 2 diabetic patients in rural Shanghai. METHODS: A cross-sectional study in type 2 diabetic patients was conducted in a community of Shanghai. Questionnaire, clinical examination and laboratory tests were completed to collect the information about sociodemographic and healthcare characteristics. RESULTS: A total of 1421 eligible patients with complete information were screened from 1487 type 2 diabetic patients between November 2008 and March 2009. Of them, 40.75% were men, 59.25% were women, aged 37 - 86 (61.33 ± 9.65) years old, with diabetic duration of 0.25 - 43.92 (7.85 ± 6.34) years. Among them, 43.42% had diabetic retinopathy, 21.18% had neuropathy; 69.95% met the screening definition for hypertension, 76.07% for hyperlipidemia, 15.55% for hyperuricemia and 23.65% for cardiovascular disease. The control rates of fasting blood glucose, glycosylated hemoglobin, blood pressure and serum cholesterol were 57.71%, 33.99%, 14.22% and 2.46%, respectively. The prevalence of kidney disease, diabetic nephropathy and non-diabetic renal disease was 41.31%, 18.51% and 13.44%, respectively; and 9.36% were diagnosed as renal insufficiency of unknown reasons. Age, diabetic duration, hyperuricemia, diabetic retinopathy and poor control of blood pressure were independently associated with kidney disease; age and poor control of blood pressure were independently associated with diabetic nephropathy; age and hyperuricemia were independent risk factors of renal insufficiency in patients with diabetic nephropathy. CONCLUSIONS: Although the diabetic duration of these subjects is relatively short, the prevalence of complications including diabetic nephropathy is high. The high prevalence of non-diabetic renal disease shows the importance of further screening and diagnoses for prevention. Strict control of blood glucose, blood pressure, serum cholesterol and serum uric acid are key points of cutting down the prevalence of diabetic nephropathy and chronic kidney disease.

MicroRNA­181 exerts an inhibitory role during renal fibrosis by targeting early growth response factor­1 and attenuating the expression of profibrotic markers.

Progressive renal fibrosis is a common complication of chronic kidney disease that results in end­stage renal disorder. It is well established that several microRNAs (miRs) function as critical regulators implicated in fibrotic diseases. However, the role of miR­181 in the development and progression of renal fibrosis remains unclear, and the precise mechanism has not yet been fully defined. The present study identified the functional implications of miR­181 expression during renal fibrosis. miR­181 exhibited significantly reduced expression in the serum of renal fibrosis patients and in the kidneys of mice with unilateral ureteral obstruction (UUO). In addition, miR­181 downregulated the expression of human α­smooth muscle actin (α­SMA) in response to angiotensin II stimulation. Transfection with miR­181 mimics significantly suppressed the expression levels of α­SMA, connective tissue growth factor, collagen type I α1 (COL1A1) and collagen type III α1 (COL3A1) in NRK49F cells. Notably, early growth response factor­1 (Egr1) was identified as a direct target gene of miR­181. Furthermore, in vivo experiments revealed that treatment with miR­181 agonist strongly rescued kidney impairment induced by UUO, as supported by Masson's trichrome staining of kidney tissues and reverse transcription­quantitative polymerase chain reaction analysis of COL1A1 and COL3A1 mRNA levels. Therefore, miR­181 may be regarded as an important mediator in the control of profibrotic markers during renal fibrosis via binding to Egr1, and may be a promising new target in the diagnosis and therapy of renal fibrosis.