scholarly journals TRPC5 Does Not Cause or Aggravate Glomerular Disease

2017 ◽  
Vol 29 (2) ◽  
pp. 409-415 ◽  
Author(s):  
Xuexiang Wang ◽  
Ranadheer R. Dande ◽  
Hao Yu ◽  
Beata Samelko ◽  
Rachel E. Miller ◽  
...  

Transient receptor potential channel 5 (TRPC5) is highly expressed in brain and kidney and mediates calcium influx and promotes cell migration. In the kidney, loss of TRPC5 function has been reported to benefit kidney filter dynamics by balancing podocyte cytoskeletal remodeling. However, in vivo gain-in-function studies of TRPC5 with respect to kidney function have not been reported. To address this gap, we developed two transgenic mouse models on the C57BL/6 background by overexpressing either wild-type TRPC5 or a TRPC5 ion-pore mutant. Compared with nontransgenic controls, neither transgenic model exhibited an increase in proteinuria at 8 months of age or a difference in LPS-induced albuminuria. Moreover, activation of TRPC5 by Englerin A did not stimulate proteinuria, and inhibition of TRPC5 by ML204 did not significantly lower the level of LPS-induced proteinuria in any group. Collectively, these data suggest that the overexpression or activation of the TRPC5 ion channel does not cause kidney barrier injury or aggravate such injury under pathologic conditions.

Marine Drugs ◽  
2020 ◽  
Vol 18 (10) ◽  
pp. 519
Author(s):  
Sarah Mazzotta ◽  
Gabriele Carullo ◽  
Aniello Schiano Moriello ◽  
Pietro Amodeo ◽  
Vincenzo Di Marzo ◽  
...  

Labdane diterpenes are widespread classes of natural compounds present in variety of marine and terrestrial organisms and plants. Many of them represents “natural libraries” of compounds with interesting biological activities due to differently functionalized drimane nucleus exploitable for potential pharmacological applications. The transient receptor potential channel subfamily V member 4 (TRPV4) channel has recently emerged as a pharmacological target for several respiratory diseases, including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Inspired by the labdane-like bicyclic core, a series of homodrimane-derived esters and amides was designed and synthesized by modifying the flexible tail in position 1 of (+)-sclareolide, an oxidized derivative of the bioactive labdane-type diterpene sclareol. The potency and selectivity towards rTRPV4 and hTRPV1 receptors were assessed by calcium influx cellular assays. Molecular determinants critical for eliciting TRPV4 antagonism were identified by structure-activity relationships. Among the selective TRPV4 antagonists identified, compound 6 was the most active with an IC50 of 5.3 μM. This study represents the first report of semisynthetic homodrimane TRPV4 antagonists, selective over TRPV1, and potentially useful as pharmacological tools for the development of novel TRPV4 channel modulators.


2018 ◽  
Vol 29 (8) ◽  
pp. 2099-2109 ◽  
Author(s):  
Kim A.T. Verheijden ◽  
Ramon Sonneveld ◽  
Marinka Bakker-van Bebber ◽  
Jack F.M. Wetzels ◽  
Johan van der Vlag ◽  
...  

BackgroundThe hallmark of podocytopathies, such as FSGS, is podocyte injury resulting in proteinuria. Transient receptor potential channel C6 (TRPC6) is a calcium-conducting ion channel expressed at the slit diaphragm. TRPC6 gain-of-function mutations and glomerular TRPC6 overexpression are associated with proteinuria. However, the pathways linking TRPC6 to podocyte injury, which is characterized by loss of the slit diaphragm protein nephrin, activation of several intracellular pathways (including calcineurin-NFAT signaling), and cytoskeletal rearrangement, remain elusive.MethodsWe tested whether the calcium-dependent protease calpain-1 mediates TRPC6-dependent podocyte injury in human and experimental FSGS and cultured podocytes.ResultsCompared with kidneys of healthy controls, kidneys of patients with FSGS had increased TRPC6 expression, increased calpain and calcineurin activity, and reduced expression of the calpain target Talin-1, which links the actin cytoskeleton to integrins and is critical for podocyte cytoskeletal stability. In a rat model of human FSGS, increased glomerular and urinary calpain activity associated with reduced Talin-1 abundance, enhanced calcineurin activity, and increased proteinuria. Treatment with the calpain inhibitor calpeptin prevented these effects. In cultured podocytes, pharmacologic stimulation of TRPC6-dependent calcium influx increased calpain-1 and calcineurin activity and reduced Talin-1 expression, and knockdown of TRPC6 or calpain-1 prevented these effects.ConclusionsWe elucidated a novel mechanism that links TRPC6 activity to calpain-1 activation and through Talin-1 loss and possibly, calcineurin activation, the podocyte injury characterizing FSGS. Therefore, calpain-1 and/or TRPC6 inhibition could be future therapeutic options to treat patients with FSGS or other podocytopathies.


2007 ◽  
Vol 85 (2) ◽  
pp. 81-92 ◽  
Author(s):  
Stefan Mergler ◽  
Mathias Z. Strowski ◽  
Simone Kaiser ◽  
Thomas Plath ◽  
Yvonne Giesecke ◽  
...  

2016 ◽  
Vol 27 (24) ◽  
pp. 3913-3925 ◽  
Author(s):  
Avinash Chandel ◽  
Krishna K. Das ◽  
Anand K. Bachhawat

Glutathione depletion and calcium influx into the cytoplasm are two hallmarks of apoptosis. We have been investigating how glutathione depletion leads to apoptosis in yeast. We show here that glutathione depletion in yeast leads to the activation of two cytoplasmically inward-facing channels: the plasma membrane, Cch1p, and the vacuolar calcium channel, Yvc1p. Deletion of these channels partially rescues cells from glutathione depletion–induced cell death. Subsequent investigations on the Yvc1p channel, a homologue of the mammalian TRP channels, revealed that the channel is activated by glutathionylation. Yvc1p has nine cysteine residues, of which eight are located in the cytoplasmic regions and one on the transmembrane domain. We show that three of these cysteines, Cys-17, Cys-79, and Cys-191, are specifically glutathionylated. Mutation of these cysteines to alanine leads to a loss in glutathionylation and a concomitant loss in calcium channel activity. We further investigated the mechanism of glutathionylation and demonstrate a role for the yeast glutathione S-transferase Gtt1p in glutathionylation. Yvc1p is also deglutathionylated, and this was found to be mediated by the yeast thioredoxin, Trx2p. A model for redox activation and deactivation of the yeast Yvc1p channel is presented.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Weijie Xia ◽  
Qianran Wang ◽  
Yuangang Lu ◽  
Yingru Hu ◽  
Xingcun Zhang ◽  
...  

Objective. Myofibroblast transformation has been shown to be associated with the reactive oxygen species- (ROS-) producing enzyme NADPH oxidase (Nox4). Inhibition of transient receptor potential channel canonical type 3 (TRPC3) attenuates mitochondrial calcium handling and ROS production in the vasculature of hypertensive rats. However, it remains elusive whether TRPC3 regulates mitochondrial calcium and ROS production and participates in myofibroblast transdifferentiation during wound healing. Methods and Results. In this study, we demonstrated that activation of TRPC3 by transforming growth factor β (TGFβ1) elevated myofibroblast transdifferentiation by upregulating the myofibroblast marker alpha smooth muscle actin (αSMA). Inhibition of TRPC3 with its specific inhibitor, Pyr3, significantly decreased TGFβ1-induced αSMA expression, as demonstrated by immunofluorescence. Real-time PCR and immunohistochemistry revealed higher TRPC3 and TGFβ1 mRNA expression levels in fibroblasts from hypertrophic scar (HTS) tissue than in those from normal skin tissue. TGFβ1 treatment increased TRPC3-mediated mitochondrial calcium uptake and ROS production but decreased ATP content in human fibroblasts, whereas inhibition of TRPC3 significantly reversed these effects. The beneficial effects were associated with improvements in mitochondrial respiratory function mediated by recovery of the activity of pyruvate dehydrogenase (PDH). In vivo, Trpc3-/- mice exhibited significantly attenuated myofibroblast transdifferentiation, as demonstrated by decreased αSMA, TGFβ1, fibronectin, and collagen-1 (Col1a1) protein expression in wound granulation tissues. Furthermore, TGFβ1-induced store-operated calcium entry (SOCE) was significantly decreased in fibroblasts from Trpc3-/- mice compared with those from Trpc3+/+ mice. In addition, Trpc3-/- mice exhibited significantly decreased Nox4 and phosphorylated Smad2/3 protein expression in wound granulation tissues. Conclusions. Our data indicate that TGFβ1-mediated activation of TRPC3 enhances mitochondrial calcium and ROS production, which promotes myofibroblast transdifferentiation and HTS formation. Inhibition of the TRPC3-mediated Nox4/pSmad2/3 pathway may be a useful strategy to limit HTS formation after injury.


2021 ◽  
Vol 22 (14) ◽  
pp. 7635
Author(s):  
Wioletta Zielińska ◽  
Jan Zabrzyński ◽  
Maciej Gagat ◽  
Alina Grzanka

The transient receptor potential (TRP) melastatin-like subfamily member 2 (TRPM2) is a non-selective calcium-permeable cation channel. It is expressed by many mammalian tissues, including bone marrow, spleen, lungs, heart, liver, neutrophils, and endothelial cells. The best-known mechanism of TRPM2 activation is related to the binding of ADP-ribose to the nudix-box sequence motif (NUDT9-H) in the C-terminal domain of the channel. In cells, the production of ADP-ribose is a result of increased oxidative stress. In the context of endothelial function, TRPM2-dependent calcium influx seems to be particularly interesting as it participates in the regulation of barrier function, cell death, cell migration, and angiogenesis. Any impairments of these functions may result in endothelial dysfunction observed in such conditions as atherosclerosis or hypertension. Thus, TRPM2 seems to be an attractive therapeutic target for the conditions connected with the increased production of reactive oxygen species. However, before the application of TRPM2 inhibitors will be possible, some issues need to be resolved. The main issues are the lack of specificity, poor membrane permeabilization, and low stability in in vivo conditions. The article aims to summarize the latest findings on a role of TRPM2 in endothelial cells. We also show some future perspectives for the application of TRPM2 inhibitors in cardiovascular system diseases.


2018 ◽  
Vol 5 (1) ◽  
pp. 1911-1922
Author(s):  
Bhooma Vijayaraghavan ◽  
Giri Padmanabhan ◽  
Kumaresan Ramanathan

Background: Ion channels play a crucial role in Glomerular filter damage that contributes to albuminuria. Transient receptor potential channel 5 (TRPC5) gene mediating such damage, demand for its target specific inhibition by RNA interference mechanism. Designing and selecting potential siRNA for TRPC5 gene silencing by computational analysis. Materials & Methods: The mRNA sequence was retrieved from NCBI (National Center for Biotechnology Information). siRNA sequences were designed specifically from target genes using InvivoGen siRNA wizard software. Thermodynamic RNA-RNA interactions were used to evaluate the gene silencing efficiency by minimum free energy of hybridization; the hybridization structures were also obtained using BIBISERV2-RNAHybrid. Results: The minimum free energy of hybridization of the three designed siRNAs (siRNA1, siRNA2 and siRNA3) were as follows: -28.2 kcal/mol, -24.1 kcal/mol, and-25.6 kcal/mol. Their corresponding GC content were 47.62%, 52.38% and 47.62%, respectively. Thus, siRNA1 had the least minimum free energy of hybridization (i.e. -28.2 kcal/mol) with low GC content (47.62%), and high linearity with minimal h-b index and loop structure. Conclusion: RNAi therapy can provide a new platform for efficient and targeted therapeutics. Further in vivo investigations are necessary to further validate their efficacy.


2006 ◽  
Vol 12 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Jun Chen ◽  
Marc R. Lake ◽  
Reza S. Sabet ◽  
Wende Niforatos ◽  
Steve D. Pratt ◽  
...  

Despite increasing use of cell-based assays in high-throughput screening (HTS) and lead optimization, one challenge is the adequate supply of high-quality cells expressing the target of interest. To this end, cell lines stably expressing targets are often established, maintained, and scaled up by cell culture. These steps require large investments of time and resources. Moreover, significant variability invariably occurs in cell yield, viability, expression levels, and target activities. In particular, stable expression of targets such as transient receptor potential A1 (TRPA1) causes toxicity, cell line degeneration, and loss of functional activity. Therefore, in an effort to identify TRPA1 antagonists, the authors used large-scale transiently transfected (LSTT) cells, enabling rapid establishment of assays suitable for HTS. LSTT cells, which could- be stored frozen for a long period of time (e.g., at least 42 weeks), retained TRPA1 protein expression and could be easily revived to produce robust and consistent signals in calcium influx and electrophysiological assays. Using cells from a single transfection, a chemical library of 700,000 compounds was screened, and TRPA1 antagonists were identified. The use of LSTT circumvented issues associated with stable TRPA1 expression, increased flexibility and consistency, and greatly reduced labor and cost. This approach will also be applicable to other pharmaceutical targets.


2017 ◽  
Vol 114 (51) ◽  
pp. 13561-13566 ◽  
Author(s):  
Paul C. Scherer ◽  
Nicholas W. Zaccor ◽  
Neil M. Neumann ◽  
Chirag Vasavda ◽  
Roxanne Barrow ◽  
...  

Opioids are powerful analgesics, but also carry significant side effects and abuse potential. Here we describe a modulator of the μ-opioid receptor (MOR1), the transient receptor potential channel subfamily vanilloid member 1 (TRPV1). We show that TRPV1 binds MOR1 and blocks opioid-dependent phosphorylation of MOR1 while leaving G protein signaling intact. Phosphorylation of MOR1 initiates recruitment and activation of the β-arrestin pathway, which is responsible for numerous opioid-induced adverse effects, including the development of tolerance and respiratory depression. Phosphorylation stands in contrast to G protein signaling, which is responsible for the analgesic effect of opioids. Calcium influx through TRPV1 causes a calcium/calmodulin-dependent translocation of G protein-coupled receptor kinase 5 (GRK5) away from the plasma membrane, thereby blocking its ability to phosphorylate MOR1. Using TRPV1 to block phosphorylation of MOR1 without affecting G protein signaling is a potential strategy to improve the therapeutic profile of opioids.


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