Numb activates the mTORC1 signaling pathway in proximal tubular epithelial cells by upregulating V1G1 expression.
10.12122/j.issn.1673-4254.2022.10.04
- Author:
Ze LIU
1
;
Da YOU
2
;
Yong LI
1
;
Yong Mei HE
1
;
A Fang LI
1
;
Pan LI
1
;
Chun Yan LI
1
Author Information
1. School of Nursing, Xiangnan University, Chenzhou 423000, China.
2. School of Clinical Medicine, Xiangnan University, Chenzhou 423000, China.
- Publication Type:Journal Article
- Keywords:
AMP activated protein kinas;
NRK-52E cells;
Numb;
V1G1;
mTOR complex 1
- MeSH:
Animals;
Male;
Mice;
Amino Acids/pharmacology*;
AMP-Activated Protein Kinases/metabolism*;
Cisplatin/pharmacology*;
Epithelial Cells;
Low Density Lipoprotein Receptor-Related Protein-2/metabolism*;
Mammals/metabolism*;
Mechanistic Target of Rapamycin Complex 1/metabolism*;
Membrane Proteins/metabolism*;
Mice, Inbred BALB C;
Nerve Tissue Proteins/metabolism*;
RNA, Small Interfering/metabolism*;
Signal Transduction;
Vacuolar Proton-Translocating ATPases/metabolism*
- From:
Journal of Southern Medical University
2022;42(10):1462-1469
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE:To investigate the role of Numb in regulating mammalian target of rapamycin (mTOR) complex 1 (mTORC1) signaling pathway.
METHODS:Male BALB/C mouse models of acute kidney injury (AKI) were subjected to intravenous injections of Numb-siRNA or NC-siRNA with or without intraperitoneal cisplatin injections. After the treatments, the expressions and distribution of Numb and megalin in the renal tissues of the mice were detected with immunohistochemistry, and the renal expressions of Numb, S6, p-S6, S6K1, p-S6K1, 4EBP1 and p-4EBP1 were examined with Western blotting. The proximal renal tubular epithelial cells were isolated from the mice transfected with Numb-siRNA for in vitro culture. In NRK-52E cells, the effects of amino acid stimulation, Numb knockdown, and V1G1 overexpression, alone or in combination, on expressions of Numb, S6 and p-S6 were detected with Western blotting; the expressions of AMPK and p-AMPK were also detected in transfected NRK-52E cells, mouse kidneys and cultured mouse renal tubular epithelial cells.
RESULTS:In BALB/C mice, injection of Numb-siRNA caused significant reductions of Numb and p-S6 expressions without affecting megalin expression in the renal proximal tubules (P < 0.05). Cisplatin treatment obviously upregulated p-S6K1 and p-4EBP1 expressions in the kidneys of the mice (P < 0.05), and this effect was significantly inhibited by treatment with Numb-siRNA (P < 0.05). In NRK-52E cells, amino acid stimulation significantly upregulated the expression of p-S6 (P < 0.05), which was strongly suppressed by transfection with Numb-siRNA (P < 0.05). Numb knockdown inhibited AMPK activation in NRK-52E cells, mouse kidneys and primary proximal tubular epithelial cells (P < 0.05). Numb knockdown significantly downregulated V1G1 expression in NRK-52E cells (P < 0.05), and V1G1 overexpression obviously reversed the inhibitory effect of Numb-siRNA on S6 phosphorylation (P < 0.05).
CONCLUSION:Numb promotes the activation of mTORC1 signaling in proximal tubular epithelial cells by upregulating V1G1 expression.
