scholarly journals Sweet Taste Receptors Mediated ROS-NLRP3 Inflammasome Signaling Activation: Implications for Diabetic Nephropathy

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Luping Zhou ◽  
Wei Huang ◽  
Youhua Xu ◽  
Chenlin Gao ◽  
Ting Zhang ◽  
...  

Previous studies demonstrated that ROS-NLRP3 inflammasome signaling activation was involved in the pathogenesis of diabetic nephropathy (DN). Recent research has shown that sweet taste receptors (STRs) are important sentinels of innate immunity. Whether high glucose primes ROS-NLRP3 inflammasome signaling via STRs is unclear. In this study, diabetic mouse model was induced by streptozotocin (STZ) in vivo; mouse glomerular mesangial cells (GMCs) and human proximal tubular cells were stimulated by high glucose (10, 20, and 30 mmol/L) in vitro; STR inhibitor lactisole was used as an intervention reagent to evaluate the role and mechanism of the STRs in the pathogenesis of DN. Our results showed that the expression of STRs and associated signaling components (Gα-gustducin, PLCβ2, and TRPM5) was obviously downregulated under the condition of diabetes in vivo and in vitro. Furthermore, lactisole significantly mitigated the production of intracellular ROS and reversed the high glucose-induced decrease of Ca2+ and the activation of NLRP3 inflammasome signaling in vitro (p<0.05). These combined results support the hypothesis that STRs could be involved in the activation of ROS-NLRP3 inflammasome signaling in the pathogenesis of DN, suggesting that STRs may act as new therapeutic targets of DN.

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Hong Feng ◽  
Junling Gu ◽  
Fang Gou ◽  
Wei Huang ◽  
Chenlin Gao ◽  
...  

While inflammation is considered a central component in the development in diabetic nephropathy, the mechanism remains unclear. The NLRP3 inflammasome acts as both a sensor and a regulator of the inflammatory response. The NLRP3 inflammasome responds to exogenous and endogenous danger signals, resulting in cleavage of procaspase-1 and activation of cytokines IL-1β, IL-18, and IL-33, ultimately triggering an inflammatory cascade reaction. This study observed the expression of NLRP3 inflammasome signaling stimulated by high glucose, lipopolysaccharide, and reactive oxygen species (ROS) inhibitor N-acetyl-L-cysteine in glomerular mesangial cells, aiming to elucidate the mechanism by which the NLRP3 inflammasome signaling pathway may contribute to diabetic nephropathy. We found that the expression of thioredoxin-interacting protein (TXNIP), NLRP3, and IL-1βwas observed by immunohistochemistry in vivo. Simultaneously, the mRNA and protein levels of TXNIP, NLRP3, procaspase-1, and IL-1βwere significantly induced by high glucose concentration and lipopolysaccharide in a dose-dependent and time-dependent manner in vitro. This induction by both high glucose and lipopolysaccharide was significantly inhibited by N-acetyl-L-cysteine. Our results firstly reveal that high glucose and lipopolysaccharide activate ROS/TXNIP/ NLRP3/IL-1βinflammasome signaling in glomerular mesangial cells, suggesting a mechanism by which inflammation may contribute to the development of diabetic nephropathy.


2013 ◽  
Vol 183 (2) ◽  
pp. 606-611 ◽  
Author(s):  
Rizwan M. Chaudhry ◽  
Alok Garg ◽  
Mohamed M. Abdelfatah ◽  
Judith A. Duenes ◽  
Michael G. Sarr

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Bin Leng ◽  
Yingjie Zhang ◽  
Xinran Liu ◽  
Zhen Zhang ◽  
Yang Liu ◽  
...  

Long-term exposure to high glucose induces vascular endothelial inflammation that can result in cardiovascular disease. Astragaloside IV (As-IV) is widely used for anti-inflammatory treatment of cardiovascular diseases. However, its mechanism of action is still not fully understood. In this study, we investigated the effect of As-IV on high glucose-induced endothelial inflammation and explored its possible mechanisms. In vivo, As-IV (40 and 80 mg/kg/d) was orally administered to rats for 8 weeks after a single intraperitoneal injection of streptozotocin (STZ, 65 mg/kg). In vitro, human umbilical vein endothelial cells (HUVECs) were treated with high glucose (33 mM glucose) in the presence or absence of As-IV, NPS2143 (CaSR inhibitor), BAY 11-7082 (NF-κB p65 inhibitor), and INF39 (NLRP3 inhibitor), and overexpression of CaSR was induced by infection of CaSR-overexpressing lentiviral vectors to further discuss the anti-inflammatory property of As-IV. The results showed that high glucose increased the expression of interleukin-18 (IL-18), interleukin-1β (IL-1β), NLRP3, caspase-1, and ASC, as well as the protein level of TLR4, nucleus p65, and CaSR. As-IV can reverse these changes in vivo and in vitro. Meanwhile, NPS2143, BAY 11-7082, and INF39 could significantly abolish the high glucose-enhanced NLRP3, ASC, caspase-1, IL-18, and IL-1β expression in vitro. In addition, both NPS2143 and BAY 11-7082 attenuated high glucose-induced upregulation of NLRP3, ASC, caspase-1, IL-18, and IL-1β expression. In conclusion, this study suggested that As-IV could inhibit high glucose-induced NLRP3 inflammasome activation and subsequent secretion of proinflammatory cytokines via inhibiting TLR4/NF-κB signaling pathway and CaSR, which provides new insights into the anti-inflammatory activity of As-IV.


2004 ◽  
Vol 286 (1) ◽  
pp. F134-F143 ◽  
Author(s):  
Shinya Mizuno ◽  
Toshikazu Nakamura

Diabetic nephropathy is now the leading cause of end-stage renal diseases, and glomerular sclerotic injury is an initial event that provokes renal dysfunction during processes of diabetes-linked kidney disease. Growing evidence shows that transforming growth factor-β1 (TGF-β1) plays a key role in this process, especially in eliciting hypertrophy and matrix overaccumulation. Thus it is important to find a ligand system to antagonize the TGF-β1-mediated pathogenesis under high-glucose conditions. Herein, we provide evidence that hepatocyte growth factor (HGF) targets mesangial cells, suppresses TGF-β1 production, and minimizes glomerular sclerotic changes, using streptozotocin-induced diabetic mice. In our murine model, glomerular sclerogenesis (such as tuft area expansion and collagen deposition) progressed between 6 and 10 wk after the induction of hyperglycemia, during a natural course of diabetic disease. Glomerular HGF expression levels in the diabetic kidney transiently increased but then declined below a basal level, with manifestation of glomerular sclerogenesis. When anti-HGF IgG was injected into mice for 2 wk (i.e., from weeks 4 to 6 after onset of hyperglycemia), these glomerular changes were significantly aggravated. When recombinant HGF was injected into the mice for 4 wk (i.e., between 6 and 10 wk following streptozotocin treatment), the progression of glomerular hypertrophy and sclerosis was almost completely inhibited, even though glucose levels remained unchanged (>500 mg/dl). Even more important, HGF repressed TGF-β1 production in glomerular mesangial cells even under hyperglycemic conditions both in vitro and in vivo. Consequently, not only albuminuria but also tubulointerstitial fibrogenesis were attenuated by HGF. Overall, HGF therapy inhibited the onset of renal dysfunction in the diabetic mice. On the basis of these findings, we wish to emphasize that HGF plays physiological and therapeutic roles in blocking renal fibrogenesis during a course of diabetic nephropathy.


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Minghua Zhang ◽  
Liang Feng ◽  
Junfei Gu ◽  
Liang Ma ◽  
Dong Qin ◽  
...  

Oxidative stress (OS) has been regarded as one of the major pathogeneses of diabetic nephropathy (DN) through damaging kidney which is associated with renal cells dysfunction. The aim of this study was to investigate whether Moutan Cortex (MC) could protect kidney function against oxidative stressin vitroorin vivo. The compounds in MC extract were analyzed by HPLC-ESI-MS. High-glucose-fat diet and STZ (30 mg kg−1) were used to induce DN rats model, while 200 μg mL−1AGEs were for HBZY-1 mesangial cell damage. The treatment with MC could significantly increase the activity of SOD, glutathione peroxidase (GSH-PX), and catalase (CAT). However, lipid peroxidation malondialdehyde (MDA) was reduced markedlyin vitroorin vivo. Furthermore, MC decreased markedly the levels of blood glucose, serum creatinine, and urine protein in DN rats. Immunohistochemical assay showed that MC downregulated significantly transforming growth factor beta 2 (TGF-β2) protein expression in renal tissue. Our data provided evidence to support this fact that MC attenuated OS in AGEs-induced mesangial cell dysfunction and also in high-glucose-fat diet and STZ-induced DN rats.


2020 ◽  
Vol 40 (6) ◽  
Author(s):  
MingJun Shi ◽  
PingPing Tian ◽  
ZhongQiang Liu ◽  
Fan Zhang ◽  
YingYing Zhang ◽  
...  

Abstract Diabetic nephropathy (DN) commonly causes end-stage renal disease (ESRD). Increasing evidence indicates that abnormal miRNA expression is tightly associated with chronic kidney disease (CKD). This work aimed to investigate whether miR-27a can promote the occurrence of renal fibrosis in DN by suppressing the expression of secreted frizzled-related protein 1 (Sfrp1) to activate Wnt/β-catenin signalling. Therefore, we assessed the expression levels of miR-27a, Sfrp1, Wnt signalling components, and extracellular matrix (ECM)-related molecules in vitro and in vivo. Sfrp1 was significantly down-regulated in a high-glucose environment, while miR-27a levels were markedly increased. A luciferase reporter assay confirmed that miR-27a down-regulated Sfrp1 by binding to the 3′ untranslated region directly. Further, NRK-52E cells under high-glucose conditions underwent transfection with miR-27a mimic or the corresponding negative control, miR-27a inhibitor or the corresponding negative control, si-Sfrp1, or combined miR-27a inhibitor and si-Sfrp1. Immunoblotting and immunofluorescence were performed to assess the relative expression levels of Wnt/β-catenin signalling and ECM components. The mRNA levels of Sfrp1, miR-27a, and ECM-related molecules were also detected by quantitative real-time PCR (qPCR). We found that miR-27a inhibitor inactivated Wnt/β-catenin signalling and reduced ECM deposition. Conversely, Wnt/β-catenin signalling was activated, while ECM deposition was increased after transfection with si-Sfrp1. Interestingly, miR-27a inhibitor attenuated the effects of si-Sfrp1. We concluded that miR-27a down-regulated Sfrp1 and activated Wnt/β-catenin signalling to promote renal fibrosis.


2021 ◽  
Author(s):  
Duojun Qiu ◽  
Shan Song ◽  
Yawei Bian ◽  
Chen Yuan ◽  
wei zhang ◽  
...  

Abstract Background: Diabetic nephropathy is one of the main complications of diabetes, inflammation and fibrosis play an important role in its progress. NAD (P) H: quinone oxidoreductase 1 (NQO1) protects cells from oxidative stress and toxic quinone damage. In present study, we aimed to investigate the protective effects and underlying mechanisms of NQO1 on diabetes-induced renal inflammation and fibrosis. Methods: In vivo, adeno-associated virus serotype 9 was used to infect the kidneys of type 2 diabetes model db/db mice to overexpress NQO1. In vitro, human renal tubular epithelial cells (HK-2) transfected with NQO1 pcDNA were cultured in high glucose. The gene and protein expression were assessed by quantitative real-time PCR, western blot, immunofluorescence, and immunohistochemical staining. Mitochondrial reactive oxygen species was detected by MitoSox red. Result: Our study revealed that the expression of NQO1 was markedly down-regulated, Toll-like receptor 4 (TLR4) and TGF-β1 upregulated in vivo and in vitro under diabetic conditions. Overexpression of NQO1 suppressed pro-inflammatory cytokines secretion (IL-6, TNF-α, MCP-1), extracellular matrix (ECM) accumulation (collagen Ⅳ, Fibronectin) and epithelial-mesenchymal transition (EMT) (α-SMA, E-cadherin) in db/db mice kidney and high glucose cultured human renal tubular cells (HK-2). Furthermore, NQO1 overexpression ameliorated high glucose-induced TLR4/NF-κB and TGF-β/Smad pathway activation. Mechanistic studies demonstrated that TLR4 inhibitor (TAK-242) suppressed TLR4/NF-κB signaling pathway, pro-inflammatory cytokines secretion, EMT and ECM-related protein expression in HG-exposed HK-2 cells. In addition, we found that antioxidants NAC and tempol increased the expression of NQO1, decreased the expression of TLR4, TGF-β1, Nox1, Nox4 and ROS production in HK-2 cells cultured with high glucose. Conclusions: These above data suggest that NQO1 alleviates diabetes-induced renal inflammation and fibrosis by regulating TLR4/NF-κB and TGF-β/Smad signaling pathways.


2019 ◽  
Vol 33 (8) ◽  
pp. 9279-9290 ◽  
Author(s):  
Qi‐Jin Zhu ◽  
Mei Zhu ◽  
Xing‐Xin Xu ◽  
Xiao‐Ming Meng ◽  
Yong‐Gui Wu

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