Effects of diadenosine polyphosphates, ATP and angiotensin II on membrane voltage and membrane conductances of rat mesangial cells

1995 ◽  
Vol 430 (5) ◽  
pp. 713-720 ◽  
Author(s):  
R. Kleta ◽  
J. Hirsch ◽  
S. Heindenreich ◽  
H. Schl�ter ◽  
W. Zidek ◽  
...  
1994 ◽  
Vol 17 (2) ◽  
pp. 62-72 ◽  
Author(s):  
Joachim Gloy ◽  
Rainer Greger ◽  
Peter Schollmeyer ◽  
Markus Huber ◽  
Hermann Pavenstädt

2011 ◽  
Vol 13 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Luciana G Pereira ◽  
Carine P Arnoni ◽  
Edgar Maquigussa ◽  
Priscila C Cristovam ◽  
Juliana Dreyfuss ◽  
...  

The prorenin receptor [(P)RR] is upregulated in the diabetic kidney and has been implicated in the high glucose (HG)-induced overproduction of profibrotic molecules by mesangial cells (MCs), which is mediated by ERK1/2 phosphorylation. The regulation of (P)RR gene transcription and the mechanisms by which HG increases (P)RR gene expression are not fully understood. Because intracellular levels of angiotensin II (AngII) are increased in MCs stimulated with HG, we used this in vitro system to evaluate the possible role of AngII in (P)RR gene expression and function by comparing the effects of AT1 receptor blockers (losartan or candesartan) and (P)RR mRNA silencing (siRNA) in human MCs (HMCs) stimulated with HG. HG induced an increase in (P)RR and fibronectin expression and in ERK1/2 phosphorylation. These effects were completely reversed by (P)RR siRNA and losartan but not by candesartan (an angiotensin receptor blocker that, in contrast to losartan, blocks AT1 receptor internalization). These results suggest that (P)RR gene activity may be controlled by intracellular AngII and that HG-induced ERK1/2 phosphorylation and fibronectin overproduction are primarily induced by (P)RR activation. This relationship between AngII and (P)RR may constitute an additional pathway of MC dysfunction in response to HG stimulation.


2002 ◽  
Vol 82 (1) ◽  
pp. 131-185 ◽  
Author(s):  
Richard J. Roman

Recent studies have indicated that arachidonic acid is primarily metabolized by cytochrome P-450 (CYP) enzymes in the brain, lung, kidney, and peripheral vasculature to 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) and that these compounds play critical roles in the regulation of renal, pulmonary, and cardiac function and vascular tone. EETs are endothelium-derived vasodilators that hyperpolarize vascular smooth muscle (VSM) cells by activating K+channels. 20-HETE is a vasoconstrictor produced in VSM cells that reduces the open-state probability of Ca2+-activated K+channels. Inhibitors of the formation of 20-HETE block the myogenic response of renal, cerebral, and skeletal muscle arterioles in vitro and autoregulation of renal and cerebral blood flow in vivo. They also block tubuloglomerular feedback responses in vivo and the vasoconstrictor response to elevations in tissue Po2both in vivo and in vitro. The formation of 20-HETE in VSM is stimulated by angiotensin II and endothelin and is inhibited by nitric oxide (NO) and carbon monoxide (CO). Blockade of the formation of 20-HETE attenuates the vascular responses to angiotensin II, endothelin, norepinephrine, NO, and CO. In the kidney, EETs and 20-HETE are produced in the proximal tubule and the thick ascending loop of Henle. They regulate Na+transport in these nephron segments. 20-HETE also contributes to the mitogenic effects of a variety of growth factors in VSM, renal epithelial, and mesangial cells. The production of EETs and 20-HETE is altered in experimental and genetic models of hypertension, diabetes, uremia, toxemia of pregnancy, and hepatorenal syndrome. Given the importance of this pathway in the control of cardiovascular function, it is likely that CYP metabolites of arachidonic acid contribute to the changes in renal function and vascular tone associated with some of these conditions and that drugs that modify the formation and/or actions of EETs and 20-HETE may have therapeutic benefits.


1991 ◽  
Vol 261 (5) ◽  
pp. F808-F814 ◽  
Author(s):  
H. Matsunaga ◽  
N. Yamashita ◽  
Y. Miyajima ◽  
T. Okuda ◽  
H. Chang ◽  
...  

We used the patch-clamp technique to clarify the nature of ion channels in renal mesangial cells in culture. In the cell-attached mode most patches were silent in the absence of agonists. In some patches a 25-pS nonselective channel was observed. This 25-pS cation channel was consistently observed in inside-out patches, and it was activated by intracellular Ca2+. Excised patch experiments also revealed the existence of a 40-pS K+ channel, which was activated by intracellular Ca2+. This 40-pS K+ channel was observed infrequently in the cell-attached mode. The activities of both channels were increased by arginine vasopressin or angiotensin II, resulting from an increase in intracellular Ca2+ concentration.


2009 ◽  
Vol 30 (8) ◽  
pp. 1132-1137 ◽  
Author(s):  
Hong Xue ◽  
Ping Yuan ◽  
Li Zhou ◽  
Tai Yao ◽  
Yu Huang ◽  
...  

1997 ◽  
Vol 272 (6) ◽  
pp. F704-F711 ◽  
Author(s):  
M. Huber-Lang ◽  
K. G. Fischer ◽  
J. Gloy ◽  
P. Schollmeyer ◽  
A. Kramer-Guth ◽  
...  

UTP and ATP induce different membrane voltage responses in rat mesangial cells. Recent studies have indicated that UTP and ATP might modulate mesangial cell function in a different manner. Here we compared the effect of UTP and ATP on membrane voltage (Vm) and ion currents in mesangial cells in primary culture, and we examined whether different nucleotide receptors are involved. In patch-clamp experiments in the fast whole cell configuration, UTP (in contrast to ATP) caused a sustained and concentration-dependent depolarization (half-maximal effective dose, 10(-5) M), but ATP caused only a transient depolarization. During the depolarization, UTP induced a sustained increase of the whole cell conductance (Gm), whereas ATP induced only a transient increase of Gm. When cells were dialyzed with Cs2SO4 and extracellular Cl- was replaced by 145 mM sodium gluconate, addition of UTP or ATP (both 10(-4) M) did not significantly increase Gm. Addition of ATP in the presence of UTP caused an additional depolarization by 5 mV, which was followed by a hyperpolarization by 21 mV. Repetitive application of ATP led to an attenuation of the ATP-induced depolarization. Then, in the presence of ATP, UTP still induced a significant depolarization by 10 mV. Suramine and reactive blue 2 did not inhibit the depolarization induced by UTP, but these inhibited the Vm response to ATP. In microfluorescence experiments, UTP and ATP caused a concentration-dependent increase of the intracellular calcium activity ([Ca2+]i) in mesangial cells. Application of both UTP and ATP had no additive effect on [Ca2+]i. The results suggest that mesangial cells possess, in addition to P2y purinoceptors, separate nucleotide receptors for UTP.


2020 ◽  
Vol 21 (19) ◽  
pp. 7003
Author(s):  
Jung Joo Yoon ◽  
Hyeon Kyoung Lee ◽  
Hye Yoom Kim ◽  
Byung Hyuk Han ◽  
Ho Sub Lee ◽  
...  

Abnormal and excessive growth of mesangial cells is important in the pathophysiologic processes of diabetes-associated interstitial fibrosis and glomerulosclerosis, leading to diabetic nephropathy, which eventually turns into end-stage renal disease. Sauchinone, a biologically-active lignan isolated from aerial parts of Saururus chinensis, has anti-inflammatory and anti-viral activities effects on various cell types. However, there are no studies reporting the effects of sauchinone on diabetic nephropathy. The present study aims to investigate the role of sauchinone in mesangial cell proliferation and fibrosis induced by angiotensin II, as well as the underlying mechanisms of these processes. Human renal mesangial cells were induced by angiotensin II (AngII, 10 μM) in the presence or absence of sauchinone (0.1–1 μM) and incubated for 48 h. In this study, we found that AngII induced mesangial cell proliferation, while treatment with sauchinone inhibited the cell proliferation in a dose-dependent manner. Pre-treatment with sauchinone induced down-regulation of cyclins/CDKs and up-regulation of CDK inhibitor, p21, and p27kip1 expression. In addition, AngII-enhanced expression of fibrosis biomarkers such as fibronectin, collagen IV, and connective tissue growth factor (CTGF), which was markedly attenuated by sauchinone. Sauchinone also decreased AngII-induced TGF-β1 and Smad-2, Smad-3, and Smad-4 expression. This study further revealed that sauchinone ameliorated AngII-induced mesangial inflammation through disturbing activation of inflammatory factors, and NLRP3 inflammasome, which is composed of the NLRP3 protein, procaspase-1, and apoptosis-associated speck-like protein containing a CARD (ASC). Moreover, pretreatment of sauchinone inhibited NF-κB translocation and ROS production in AngII-exposed mesangial cells. These data suggest that sauchinone has a protective effect on renal proliferation, fibrosis and inflammation. Therefore, sauchinone might be a potential pharmacological agent in prevention of AngII-induced renal damage leading to diabetic nephropathy.


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