scholarly journals High glucose inhibits nitric oxide production in cultured rat mesangial cells.

1997 ◽  
Vol 8 (8) ◽  
pp. 1276-1282
Author(s):  
H Trachtman ◽  
S Futterweit ◽  
D L Crimmins

Hyperglycemia directly contributes to the development of diabetic nephropathy. A high-serum glucose concentration alters intraglomerular hemodynamics and promotes deposition of extracellular matrix in the kidney. Nitric oxide (NO) is a short-lived messenger molecule that participates in the regulation of renal blood flow, GFR, and mesangial matrix accumulation. Therefore, in this study it was tested whether high glucose directly modulates NO synthesis by rat mesangial cells in vitro by measuring the accumulation of nitrite, the stable metabolite of NO, in the incubation media. Raising the external glucose concentration to 33.3 mM for 24 to 72 h reduced nitrite levels in cell supernatants in a time-dependent manner to a nadir of 14 +/- 3% of the amount in normal glucose media (5.6 mM) (P < 0.01). The decline in NO synthesis in high glucose media was paralleled by decreased cyclic guanosine monophosphate generation; however, there was no alteration in rat mesangial cell expression of inducible NO synthase protein. The suppressive effect of high glucose on NO production by mesangial cells was not modified by inhibition of protein kinase C (H-7), the addition of antioxidants (vitamin E or superoxide dismutase), or a pan-specific anti-transforming growth factor-beta antibody. An elevated ambient glucose caused a time-dependent reduction in mesangial cell L-arginine content. Addition of L-arginine (10 to 20 mM) to external media partially reversed the inhibitory effect of high glucose on mesangial cell NO production in a dose-dependent manner. The highest dose of L-arginine (20 mM) increased mesangial cell L-arginine content to comparable levels in normal and high glucose media. These results indicate that high glucose causes depletion of L-arginine in mesangial cells and compromises NO synthesis. Limitation in the metabolic precursor and other, as yet unidentified, factors act to reduce NO production by mesangial cells in the presence of an elevated ambient glucose level, a change that may play a role in the development of diabetic glomerulosclerosis.

2019 ◽  
Vol 47 (05) ◽  
pp. 1043-1056 ◽  
Author(s):  
Wei-Tien Chang ◽  
Chang-Qing Li ◽  
Chin-Wan Hsu ◽  
Chunpei Lee ◽  
Hsien-Hao Huang ◽  
...  

Baicalein is a natural flavonoid with anti-oxidant activities protecting against ischemia/reperfusion (I/R) injury. Previous studies suggest that oxidative burst early after reperfusion accelerates cell death. We therefore investigated the critical therapeutic window of baicalein by examining the timing of baicalein treatment in relation to its oxidant modulating and cytoprotective effects. Using an established chick cardiomyocyte model of I/R, we administered baicalein at various time points after reperfusion and assessed cell viability and the profiles of reactive oxygen species (ROS), nitric oxide (NO), and Akt phosphorylation. Baicalein administered at the onset of reperfusion resulted in a concentration-dependent reduction of cell death (25 [Formula: see text]M [Formula: see text]%, 50[Formula: see text][Formula: see text]M [Formula: see text]%, 100[Formula: see text][Formula: see text]M [Formula: see text]%, vs. I/R control [Formula: see text]%, all [Formula: see text]). Baicalein (100[Formula: see text][Formula: see text]M) timely and effectively scavenged ROS burst and enhanced NO production in the early reperfusion phase. Cotreatment with NO synthase (NOS) inhibitor l-NAME (200[Formula: see text][Formula: see text]M) partially abrogated the cytoprotective effect. Baicalein (100[Formula: see text][Formula: see text]M) given after reperfusion lost protective effect in a time-dependent manner with cytoprotection completely lost if [Formula: see text][Formula: see text]min. Even with only 15-min delay after reperfusion, the ROS scavenging effect was abolished and the NO enhancing effect markedly reduced. The phosphorylation of Akt, an upstream regulator of eNOS, also diminished as the delay lengthened. In conclusion, baicalein treatment after reperfusion confers cardioprotection in a concentration- and time-dependent manner. The critical therapeutic window lies in the early reperfusion phase, during which ROS scavenging and Akt-eNOS mediated NO signaling are most effective.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zhigui Wu ◽  
Wenxian Yin ◽  
Mengqi Sun ◽  
Yuankai Si ◽  
Xiaoxiao Wu ◽  
...  

Objective. To explore the role and mechanism of BKCa in diabetic kidney disease. Methods. Rat mesangial cells (MCs) HBZY-1 were cultured with high glucose to simulate the high-glucose environment of diabetic kidney disease in vivo. The effects of large conductance calcium-activated potassium channel (BKCa) on proliferation, migration, and apoptosis of HBZY-1 cells were observed. The contents of transforming growth factor beta 1 (TGF-β1), Smad2/3, collagen IV (Col IV), and fibronectin (FN) in the extracellular matrix were also observed. Results. High glucose significantly damaged HBZY-1 cells, which enhanced the ability of cell proliferation, migration, and apoptosis, and increased the secretion of Col IV and FN. Inhibition of BKCa and TGF-β1/Smad2/3 signaling pathways can inhibit the proliferation, migration, and apoptosis of HBZY-1 cells and suppress the secretion of Col IV and FN. The effect of excitation is the opposite. Conclusions. BKCa regulates mesangial cell proliferation, migration, apoptosis, and secretion of Col IV and FN and is associated with TGF-β1/Smad2/3 signaling pathway.


2013 ◽  
Vol 41 (01) ◽  
pp. 71-83 ◽  
Author(s):  
Jung Joo Yoon ◽  
Yun Jung Lee ◽  
So Min Lee ◽  
Song Nan Jin ◽  
Dae Gill Kang ◽  
...  

Mesangial cell proliferation is correlated with the progression of renal failure. The purpose of this study was to determine whether a water extract of Poria cocos Wolf (WPC), a well-known medicinal plant, regulates rat mesangial cell proliferation in the presence of high glucose (HG). HG significantly accelerated [3H]-thymidine incorporation, which was inhibited by WPC (1–50 μg/mL) in a dose-dependent manner. Cell migration and fibronectin mRNA expression data also supported the anti-proliferative effect of WPC. Western blot analysis revealed that pretreatment with WPC decreased the expression of cyclins and cyclin-dependent kinases (CDKs) and promoted the expression of p21waf1/cip1and p27kip1. WPC also suppressed HG-induced p38 mitogen-activated protein kinase (p38 MAPK) and extracellular-signal-regulated kinase 1/2 (ERK 1/2) phosphorylation. Furthermore, WPC inhibited HG-induced production of dichlorofluorescein (DCF)-sensitive intracellular reactive oxygen species (ROS). In conclusion, HG promoted mesangial cell proliferation, and WPC inhibited this activity, at least in part, via induction of cell cycle arrest and activation of anti-oxidant properties. Taken together, these results suggest that P. cocos may be a potent regulator of HG-induced proliferation.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Xueqin Zhou ◽  
Chenlin Gao ◽  
Wei Huang ◽  
Maojun Yang ◽  
Guo Chen ◽  
...  

Recent studies have shown that sumoylation is a posttranslational modification involved in regulation of the transforming growth factor-β(TGF-β) signaling pathway, which plays a critical role in renal fibrosis in diabetic nephropathy (DN). However, the role of sumoylation in the regulation of TGF-βsignaling in DN is still unclear. In the present study, we investigated the expression of SUMO (SUMO1 and SUMO2/3) and Smad4 and the interaction between SUMO and Smad4 in cultured rat mesangial cells induced by high glucose. We found that SUMO1 and SUMO2/3 expression was significantly increased in the high glucose groups compared to the normal groupP<0.05. Smad4 and fibronectin (FN) levels were also increased in the high glucose groups in a dose-dependent manner. Coimmunoprecipitation and confocal laser scanning revealed that Smad4 interacted and colocalized with SUMO2/3, but not with SUMO1 in mesangial cells. Sumoylation (SUMO2/3) of Smad4 under high glucose condition was strongly enhanced compared to normal controlP<0.05. These results suggest that high glucose may activate TGF-β/Smad signaling through sumoylation of Samd4 by SUMO2/3 in mesangial cells.


Author(s):  
Zhaohui Fang ◽  
Xiu Hu ◽  
Zhi Chen ◽  
Jing Xie ◽  
Di Wu ◽  
...  

IntroductionDiabetes mellitus (DM) is a chronic metabolic disorder characterized by elevated blood glucose level over a prolonged period, leading to severe damage in tissues including the heart, blood vessels, eyes and the kidneys. Danzhi Jiangtang Capsule (DJC) is an effective drug for diabetes, but the mechanism responsible for its efficacy remains unknown. This study aimed to explore the effective ingredient of DJC that ameliorated diabetes and the possible mechanisms.Material and methodsWe orally treated streptozotocin (STZ)-induced diabetic rats with 540 mg/kg DIC or the same dose of its four active components, namely Leeches, Pseudostellaria Polysaccharides (PP), Paeonia Suffruticosa Andr (PSA) and Rehmannia Glutinosa Libosch (RGL), respectively for 8 weeks.ResultsAlthough all of these components could reduce blood glucose levels in diabetic rats, the extent of alleviation of DJC was more pronounced than all of its four ingredients. Unlike the other three components, Leeches is the only effective ingredient of DJC that decreased tetrahydrobiopterin (BH4) oxidation to activate endothelial nitric oxide synthase (eNOS), and increased nitric oxide (NO) production, leading to improved endothelium-dependent relaxation both in diabetic rats and in immortalized human mesangial cells under the stimulation of high glucose.ConclusionsLeeches could alleviate diabetic macroangiopathy by inhibiting NO release in endothelial cells under high-glucose condition.


2003 ◽  
Vol 284 (3) ◽  
pp. F455-F466 ◽  
Author(s):  
Barinder P. S. Kang ◽  
Stanley Frencher ◽  
Venkatesh Reddy ◽  
Alex Kessler ◽  
Ashwani Malhotra ◽  
...  

Reactive oxygen species are recognized as important mediators of biological responses. Hyperglycemia promotes the intracellular generation of superoxide anion and hydrogen peroxide. In several cell lines, oxidant stress has been linked to the activation of death programs. Here, we report for the first time that high ambient glucose concentration induces apoptosis in murine and human mesangial cells by an oxidant-dependent mechanism. The signaling cascade activated by glucose-induced oxidant stress included the heterodimeric redox-sensitive transcription factor NF-κB, which exhibited an upregulation in p65/c-Rel binding activity and suppressed binding activity of the p50 dimer. Recruitment of NF-κB and mesangial cell apoptosis were both inhibited by antioxidants, implicating oxidant-induced activation of NF-κB in the transmission of the death signal. The genetic program for glucose-induced mesangial cell apoptosis was characterized by an upregulation of the Bax/Bcl-2 ratio. In addition, phosphorylation of the proapoptotic protein Bad was attenuated in mesangial cells maintained at high-glucose concentration, favoring progression of the apoptotic process. These perturbations in the expression and phosphorylation of the Bcl-2 family were coupled with the release of cytochrome c from mitochondria and caspase activation. Our findings indicate that in mesangial cells exposed to high ambient glucose concentration, oxidant stress is a proximate event in the activation of the death program, which culminates in mitochondrial dysfunction and caspase-3 activation, as the terminal event.


2017 ◽  
Vol 41 (3) ◽  
pp. 1035-1043 ◽  
Author(s):  
Tao Ding ◽  
Wei Chen ◽  
Juan Li ◽  
Jiarong Ding ◽  
Xiaobin Mei ◽  
...  

Background/Aims: Overproliferation of mesangial cells was believed to play an important role in the progress of diabetic nephropathy, one of the primary complications of diabetes. Hydrogen sulfide (H2S), a well-known and pungent gas with the distinctive smell of rotten eggs, was discovered to play a protective role in diabetic nephropathy. Methods: MTT assay was used to examine the viability of mesangial cells. Small interfering RNA was used to knock down the expression of TLR4 while specific inhibitor LY294002 to suppress the function of PI3K. H2S generation rate was determined by a H2S micro-respiration sensor. Results: Glucose of 25mM induced significant mesangial cells proliferation, which was accomplished by significantly inhibited endogenous H2S synthesis. And exogenous H2S treatment by NaHS markedly mitigated the overproliferation of mouse mesangial cells. Furthermore, it was found that H2S deficiency could result in TLR4 activation. And H2S supplementation remarkably inhibited TLR4 expression and curbed the mesangial cell overproliferation. Besides, PI3K/Akt pathway inhibition also significantly ameliorated the cell overproliferation. Conclusion: High glucose (HG) induces mouse mesangial cell overproliferation via inhibition of hydrogen sulfide synthesis in a TLR-4-dependent manner. And PI3K/Akt pathway might also play a vital part in the HG-induced mesangial cell overproliferation.


2000 ◽  
Vol 279 (1) ◽  
pp. E11-E17 ◽  
Author(s):  
Yaoxian Ding ◽  
Nosratola D. Vaziri ◽  
Richard Coulson ◽  
Vaijinath S. Kamanna ◽  
Daeyoung D. Roh

Diabetes is associated with endothelial dysfunction and increased risk of hypertension, cardiovascular disease, and renal complications. Earlier studies have revealed that hyperglycemia impairs nitric oxide (NO) production and diabetes causes endothelial dysfunction in humans and experimental animals. This study was designed to test the effects of altered concentrations of glucose, insulin, and glucagon, the principal variables in types I and II diabetes, on NO production and endothelial NO synthase (eNOS) expression in cultured human coronary endothelial cells. Cultured endothelial cells were incubated in the presence of glucose at either normal (5.6 mM) or high (25 mM) concentrations for 7 days. The rates of basal and bradykinin-stimulated NO production (nitrate + nitrite) and eNOS protein expression (Western blot) were then determined at the basal condition and in the presence of insulin (10−8 and 10−7 M), glucagon (10−8 and 10−7 M), or both. Incubation with a high-glucose concentration for 7 days significantly downregulated, whereas insulin significantly upregulated, basal and bradykinin-stimulated NO production and eNOS expression in cultured endothelial cells. The stimulatory action of insulin was mitigated by high-glucose concentration and abolished by cotreatment of cells with glucagon. Thus hyperglycemia, insulinopenia, and hyperglucagonemia, which frequently coexist in diabetes, can work in concert to suppress NO production by human coronary artery endothelial cells.


1997 ◽  
Vol 8 (10) ◽  
pp. 1525-1536
Author(s):  
I Z Pawluczyk ◽  
K P Harris

Glomerulosclerosis is the final outcome of a number of different causes of glomerular injury, during which the structures of the glomerulus are obliterated by extracellular matrix. Accumulating evidence suggests that infiltrating macrophages play a pivotal role in the progression to glomerulosclerosis. The present study defines the role played by macrophages at both cellular and molecular levels in the initiation of the sclerotic process in cultured rat mesangial cells. Macrophage-conditioned medium (MPCM) generated from thioglycollate-elicited, lipopolysaccharide-stimulated macrophages upregulated mesangial cell fibronectin production in a dose- and time-dependent manner, independently of cell proliferation. Immunoprecipitation of metabolically labeled 35S-fibronectin confirmed that the matrix protein was synthesized de novo. The genes for fibronectin and the matrix proteins laminin and collagen IV were also found to be upregulated 2.86 +/- 0.24-, 4.94 +/- 0.17-, and 3.03 +/- 0.31-fold over controls, respectively (P < 0.001). Macrophage modulation of matrix turnover was suggested by an upregulation of both transin and tissue inhibitor of metalloproteinase-1 gene transcription. Transforming growth factor (TGF) beta1, platelet-derived growth factor, tumor necrosis factor (TNF) alpha, or interleukin (IL)-1beta could not be detected in the MPCM per se; however, TGFbeta1 and platelet-derived growth factor AB were found to be secreted into mesangial cell culture supernatants. Secretion was augmented 1.69 +/- 0.16- and 2.28 +/- 0.28-fold, respectively (both P < 0.001), in response to MPCM. Northern blot analysis demonstrated that protein secretion had been preceded by upregulation of the genes for these cytokines (2.2 +/- 0.4-fold [P < 0.001] and 5.7 +/- 1.2-fold [P < 0.004], respectively). Incubation of MPCM with either neutralizing antibody or the growth factor receptor antagonist suramin demonstrated that TGFbeta1 played a significant, although minor, role in MPCM-stimulated fibronectin production. In conclusion, this study provides compelling evidence for a direct role of macrophages in the progression to glomerulosclerosis.


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