scholarly journals Cell-autonomous regulation of epithelial cell quiescence by calcium channel Trpv6

2019 ◽  
Author(s):  
Yi Xin ◽  
Allison Malick ◽  
Meiqin Hu ◽  
Chengdong Liu ◽  
Heya Batah ◽  
...  

AbstractEpithelial homeostasis and regeneration require a pool of quiescent cells. How the quiescent cells are established and maintained is poorly understood. Here we report that Trpv6, a cation channel responsible for epithelial Ca2+ absorption, functions as a key regulator of cellular quiescence. Genetic deletion and pharmacological blockade of Trpv6 promoted zebrafish epithelial cells to exit from quiescence and re-enter the cell cycle. Reintroducing Trpv6, but not its channel dead mutant, restored the quiescent state. Ca2+ imaging showed that Trpv6 is constitutively open in vivo. Mechanistically, Trpv6-mediated Ca2+ influx maintained the quiescent state by suppressing insulin-like growth factor (IGF)-mediated Akt and Tor signaling. In zebrafish epithelia and human colon cancer cells, Trpv6/TRPV6 elevated intracellular Ca2+ levels and activated PP2A, which down-regulated IGF signaling and promoted the quiescent state. Our findings suggest that Trpv6 mediates constitutive Ca2+ influx into epithelial cells to continuously suppress growth factor signaling and maintain the quiescent state.

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Yi Xin ◽  
Allison Malick ◽  
Meiqin Hu ◽  
Chengdong Liu ◽  
Heya Batah ◽  
...  

Epithelial homeostasis and regeneration require a pool of quiescent cells. How the quiescent cells are established and maintained is poorly understood. Here, we report that Trpv6, a cation channel responsible for epithelial Ca2+ absorption, functions as a key regulator of cellular quiescence. Genetic deletion and pharmacological blockade of Trpv6 promoted zebrafish epithelial cells to exit from quiescence and re-enter the cell cycle. Reintroducing Trpv6, but not its channel dead mutant, restored the quiescent state. Ca2+ imaging showed that Trpv6 is constitutively open in vivo. Mechanistically, Trpv6-mediated Ca2+ influx maintained the quiescent state by suppressing insulin-like growth factor (IGF)-mediated Akt-Tor and Erk signaling. In zebrafish epithelia and human colon carcinoma cells, Trpv6/TRPV6 elevated intracellular Ca2+ levels and activated PP2A, which down-regulated IGF signaling and promoted the quiescent state. Our findings suggest that Trpv6 mediates constitutive Ca2+ influx into epithelial cells to continuously suppress growth factor signaling and maintain the quiescent state.


2001 ◽  
Vol 120 (5) ◽  
pp. A493-A493
Author(s):  
J HARDWICK ◽  
G VANDENBRINK ◽  
S VANDEVENTER ◽  
M PEPPELENBOSCH

Author(s):  
Eishin Yaoita ◽  
Masaaki Nameta ◽  
Yutaka Yoshida ◽  
Hidehiko Fujinaka

AbstractFibroblast growth factor 2 (FGF2) augments podocyte injury, which induces glomerulosclerosis, although the mechanisms remain obscure. In this study, we investigated the effects of FGF2 on cultured podocytes with interdigitating cell processes in rats. After 48 h incubation with FGF2 dynamic changes in the shape of primary processes and cell bodies of podocytes resulted in the loss of interdigitation, which was clearly shown by time-lapse photography. FGF2 reduced the gene expressions of constituents of the slit diaphragm, inflections of intercellular junctions positive for nephrin, and the width of the intercellular space. Immunostaining for the proliferation marker Ki-67 was rarely seen and weakly stained in the control without FGF2, whereas intensely stained cells were frequently found in the presence of FGF2. Binucleation and cell division were also observed, although no significant increase in cell number was shown. An in vitro scratch assay revealed that FGF2 enhanced migration of podocytes. These findings show that FGF2 makes podocytes to transition from the quiescent state into the cell cycle and change their morphology due to enhanced motility, and that the culture system in this study is useful for analyzing the pathological changes of podocytes in vivo.


2011 ◽  
Vol 436 (2) ◽  
pp. 507-516 ◽  
Author(s):  
Heping Yang ◽  
Tony W. H. Li ◽  
Jian Peng ◽  
José M. Mato ◽  
Shelly C. Lu

We have previously reported that the expression of MAT2A (methionine adenosyltransferase 2A) is increased in human colon cancer and in colon cancer cells treated with IGF-1 (insulin-like growth factor-1), which was required for its mitogenic effect. The aim of the present study was to elucidate the molecular mechanisms of IGF-1-mediated MAT2A induction. Nuclear run-on analysis confirmed that the increase in MAT2A expression lies at the transcriptional level. DNase I footprinting of the MAT2A promoter region revealed a similar protein-binding pattern in colon cancer and IGF-1-treated RKO cells. IGF-1 induced MAT2A promoter activity and increased nuclear protein binding to USF (upstream stimulatory factor)/c-Myb, YY1 (Yin and Yang 1), E2F, AP-1 (activator protein 1) and NF-κB (nuclear factor κB) consensus elements. IGF-1 increased the expression of c-Jun, FosB, MafG, p65, c-Myb, E2F-1 and YY1 at the pre-translational level. Knockdown of p65, MafG, c-Myb or E2F-1 lowered basal MAT2A expression and blunted the inductive effect of IGF-1 on MAT2A, whereas knockdown of YY1 increased basal MAT2A expression and had no effect on IGF-1-mediated MAT2A induction. Consistently, mutation of AP-1, NF-κB, E2F and USF/c-Myb elements individually blunted the IGF-1-mediated increase in MAT2A promoter activity, and combined mutations completely prevented the increase. In conclusion, IGF-1 activates MAT2A transcription by both known and novel pathways. YY1 represses MAT2A expression.


2002 ◽  
Vol 13 (5) ◽  
pp. 533-543 ◽  
Author(s):  
Jane-Jen Wang ◽  
Yaw-Terng Chern ◽  
Yuh-Fang Chang ◽  
Tsung-Yun Liu ◽  
Chin-Wen Chi

2019 ◽  
Vol 8 (12) ◽  
pp. 5662-5672 ◽  
Author(s):  
Sonoko Chikamatsu ◽  
Ken Saijo ◽  
Hiroo Imai ◽  
Koichi Narita ◽  
Yoshifumi Kawamura ◽  
...  

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