scholarly journals Dexamethasone Resisted Podocyte Injury via Stabilizing TRPC6 Expression and Distribution

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Shengyou Yu ◽  
L. Yu

TRPC6, a member of the canonical transient receptor potential channel (TRPC) subfamily, is an important cation selective ion channel on podocytes. Podocytes are highly differentiated cells located on the visceral face of glomerular basement membrane and featured by numerous foot processes, on which nephrin, podocin, and TRPC6 locate. Podocytes and the slit diaphragm (SD) between adjacent foot processes form a selective filtration barrier impermeable to proteins. TRPC6 is very critical for normal podocyte function. To investigate the function of TRPC6 in podocytes and its relation to proteinuria in kidney diseases, we over-expressed TRPC6 in podocytes by puromycin aminonucleoside (PAN) and observed the changes of foot processes, TRPC6 protein distribution, and mRNA expression. Accordingly, in this study, we further investigated the role of specific signaling mechanisms underlying the prosurvival effects of dexamethasone (DEX) on podocyte repair. Our results showed that podocytes processes of overexpressing TRPC6 were reduced remarkably. These changes could be rescued by DEX via blocking TRPC6 channel. Additionally, our results also showed an improvement in TRPC6 arrangement in the cells and decrease of mRNA expression and protein distribution. From these results, we therefore proposed that overexpression of TRPC6 in podocytes may be one of the fundamental changes relating to the dysfunction of the SD and proteinuria. DEX may be maintained the structure and function integrity of SD by blocking TRPC6 signal pathway and played an important role in mechanisms of anti-proteinuria.

Author(s):  
Yanhong Zhang ◽  
Nina Yin ◽  
Anbang Sun ◽  
Qifang Wu ◽  
Wenzhu Hu ◽  
...  

Kidney fibrosis is generally confirmed to have a significant role in chronic kidney disease, resulting in end-stage kidney failure. Epithelial–mesenchymal transition (EMT) is an important molecular mechanism contributing to fibrosis. Tubular epithelial cells (TEC), the major component of kidney parenchyma, are vulnerable to different types of injuries and are a significant source of myofibroblast by EMT. Furthermore, TRPC6 knockout plays an anti-fibrotic role in ameliorating kidney damage. However, the relationship between TRPC6 and EMT is unknown. In this study, TRPC6−/− and wild-type (WT) mice were subjected to a unilateral ureteric obstruction (UUO) operation. Primary TEC were treated with TGF-β1. Western blot and immunofluorescence data showed that fibrotic injuries alleviated with the inhibition of EMT in TRPC6−/− mice compared to WT mice. The activation of AKT-mTOR and ERK1/2 pathways was down-regulated in the TRPC6−/− mice, while the loss of Na+/K+-ATPase and APQ1 was partially recovered. We conclude that TRPC6 knockout may ameliorate kidney fibrosis by inhibition of EMT through down-regulating the AKT-mTOR and ERK1/2 pathways. This could contribute to the development of effective therapeutic strategies on chronic kidney diseases.


2021 ◽  
Author(s):  
Jochen Reiser ◽  
Onur K Polat ◽  
Elena Isaeva ◽  
Ke Zhu ◽  
Manuel Noben ◽  
...  

Background Transient receptor potential channel 5 (TRPC5) is a non-selective cationic ion channel expressed in brain, kidney and other organs where its activation underlies podocyte injury in chronic kidney diseases. Specifically, it has been suggested that a podocyte TRPC5 plasma membrane relocation and channel activation following injury results from activation of Rac-1, propagating podocyte dysfunction and proteinuria. However, previous TRPC5 transgenic mouse studies had questioned a pathogenic role for TRPC5 in podocytes. This investigation was designed to specifically evaluate podocyte Rac-1 activation in the context of functional TRPC5 or a TRPC5 pore mutant to assess effects on proteinuria. Materials and Methods We employed single cell patch-clamp studies of cultured podocytes and studied proteinuria in transgenic mouse models to characterize the effects of TRPC5 following podocyte Rac-1 activation. Results Inhibition of TRPC5 by small molecules reportedly ameliorated proteinuria in murine models of proteinuric kidney diseases. In order to directly examine TRPC5 function following Rac-1-induced podocyte injury, we analyzed TRPC5 inhibition in podocyte specific Rac-1 (active) transgenic mice. In addition, we generated a double-transgenic mouse constitutively overexpressing either TRPC5 (TRPC5WT) or a TRPC5 dominant-negative pore mutant (TRPC5DN) in concert with podocyte specific and inducible activation of active Rac-1 (Rac-1Dtg). In electrophysiological experiments, active TRPC5 was detected in primary podocytes overexpressing TRPC5 but not in podocytes with endogenous TRPC5 expression, nor with Rac-1 overexpressing podocytes. TRPC5 inhibition did not change proteinuria in mice with active podocyte Rac-1, nor did an increase or loss of TRPC5 activity affected podocyte injury in Rac-1Dtg animals. Administration of TRPC5 inhibitors, ML204 and AC1903, did not alleviate podocyte Rac-1 induced proteinuria. Conclusion TRPC5 inhibition did not modify podocyte Rac-1 induced proteinuria in mice.


Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 147
Author(s):  
Yu Fu ◽  
Peng Shang ◽  
Bo Zhang ◽  
Xiaolong Tian ◽  
Ruixue Nie ◽  
...  

In animals, muscle growth is a quantitative trait controlled by multiple genes. Previously, we showed that the transient receptor potential channel 1 (TRPC1) gene was differentially expressed in muscle tissues between pig breeds with divergent growth traits base on RNA-seq. Here, we characterized TRPC1 expression profiles in different tissues and pig breeds and showed that TRPC1 was highly expressed in the muscle. We found two single nucleotide polymorphisms (SNPs) (C-1763T and C-1604T) in TRPC1 that could affect the promoter region activity and regulate pig growth rate. Functionally, we used RNAi and overexpression to illustrate that TRPC1 promotes myoblast proliferation, migration, differentiation, fusion, and muscle hypertrophy while inhibiting muscle degradation. These processes may be mediated by the activation of Wnt signaling pathways. Altogether, our results revealed that TRPC1 might promote muscle growth and development and plays a key role in Wnt-mediated myogenesis.


2002 ◽  
Vol 92 (4) ◽  
pp. 1594-1602 ◽  
Author(s):  
Michele Sweeney ◽  
Sharon S. McDaniel ◽  
Oleksandr Platoshyn ◽  
Shen Zhang ◽  
Ying Yu ◽  
...  

Asthma is characterized by airway inflammation, bronchial hyperresponsiveness, and airway obstruction by bronchospasm and bronchial wall thickening due to smooth muscle hypertrophy. A rise in cytosolic free Ca2+ concentration ([Ca2+]cyt) may serve as a shared signal transduction element that causes bronchial constriction and bronchial wall thickening in asthma. In this study, we examined whether capacitative Ca2+ entry (CCE) induced by depletion of intracellular Ca2+ stores was involved in agonist-mediated bronchial constriction and bronchial smooth muscle cell (BSMC) proliferation. In isolated bronchial rings, acetylcholine (ACh) induced a transient contraction in the absence of extracellular Ca2+ because of Ca2+ release from intracellular Ca2+ stores. Restoration of extracellular Ca2+in the presence of atropine, an M-receptor blocker, induced a further contraction that was apparently caused by a rise in [Ca2+]cyt due to CCE. In single BSMC, amplitudes of the store depletion-activated currents ( I SOC) and CCE were both enhanced when the cells proliferate, whereas chelation of extracellular Ca2+ with EGTA significantly inhibited the cell growth in the presence of serum. Furthermore, the mRNA expression of TRPC1, a transient receptor potential channel gene, was much greater in proliferating BSMC than in growth-arrested cells. Blockade of the store-operated Ca2+channels by Ni2+ decreased I SOC and CCE and markedly attenuated BSMC proliferation. These results suggest that upregulated TRPC1 expression, increased I SOC, enhanced CCE, and elevated [Ca2+]cyt may play important roles in mediating bronchial constriction and BSMC proliferation.


2011 ◽  
Vol 110 (3) ◽  
pp. 789-798 ◽  
Author(s):  
Kaori Ono ◽  
Masako Tsukamoto-Yasui ◽  
Yoshiko Hara-Kimura ◽  
Naohiko Inoue ◽  
Yoshihito Nogusa ◽  
...  

The sympathetic thermoregulatory system controls the magnitude of adaptive thermogenesis in correspondence with the environmental temperature or the state of energy intake and plays a key role in determining the resultant energy storage. However, the nature of the trigger initiating this reflex arc remains to be determined. Here, using capsiate, a digestion-vulnerable capsaicin analog, we examined the involvement of specific activation of transient receptor potential (TRP) channels within the gastrointestinal tract in the thermogenic sympathetic system by measuring the efferent activity of the postganglionic sympathetic nerve innervating brown adipose tissue (BAT) in anesthetized rats. Intragastric administration of capsiate resulted in a time- and dose-dependent increase in integrated BAT sympathetic nerve activity (SNA) over 180 min, which was characterized by an emergence of sporadic high-activity phases composed of low-frequency bursts. This increase in BAT SNA was abolished by blockade of TRP channels as well as of sympathetic ganglionic transmission and was inhibited by ablation of the gastrointestinal vagus nerve. The activation of SNA was delimited to BAT and did not occur in the heart or pancreas. These results point to a neural pathway enabling the selective activation of the central network regulating the BAT SNA in response to a specific stimulation of gastrointestinal TRP channels and offer important implications for understanding the dietary-dependent regulation of energy metabolism and control of obesity.


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