Related Experiment Video
Updated: Apr 3, 2026
Mechanism of Kemeng Fang's Inhibition of Podocyte Apoptosis in Rats with Membranous Nephropathy through the PI3K/AKT Signaling Pathway
Published on: August 23, 2024
SGK-1 protects kidney cells against apoptosis induced by ceramide and TNF-α
D Pastore1, D Della-Morte1,2, A Coppola1
1Laboratory of Molecular Medicine, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
Abstract:
Ceramide regulates several different cellular responses including mechanisms leading to apoptosis. Serum- and glucocorticoid-inducible protein kinase (SGK)-1 is a serine threonine kinase, which activates survival pathways in response to stress stimuli. Recently, we demonstrated an anti-apoptotic role of SGK-1 in human umbilical endothelial cells treated with high glucose. In the present study, since ceramide induces apoptosis by multiple mechanisms in diabetes and its complication such as nephropathy, we aimed to investigate whether SGK-1 may protect even against apoptosis induced by ceramide in kidney cells. Human embryonic kidney (HEK)-293 cells stable transfected with SGK-1 wild type (SGK-1wt) and its dominant negative gene (SGK-1dn) have been used in this study. Apoptotic stimuli were induced by C2-ceramide and TNF-α to increase endogenous synthesis of ceramide. Upon activation with these stimuli, SGK-1wt transfected cells have a statistically significant reduction of apoptosis compared with SGK-1dn cells (P<0.001). This protection was dependent on activation of caspase-3 and Poly-ADP-ribose-polymerase-1 (PARP-1) cleavage. SGK-1 and AKT-1 two highly homologous kinases differently reacted to ceramide treatment, since SGK-1 increases in response to apoptotic stimulus while AKT-1 decreases. This enhancement of SGK-1 was dependent on p38-mitogen-activated-protein kinases (p38MAPK), cyclic-adenosine-monophosphate/protein kinase A (cAMP/PKA) and phosphoinositide-3-kinase (PI3K) pathways. Especially, by using selective LY294002 inhibitor, we demonstrated that the most involved pathway in the SGK-1 mediated process of protection was PI3K. Treatment with inhibitor of SGK-1 (GSK650394) significantly enhanced TNF-α-dependent apoptosis in HEK-293 cells overexpressing SGK-1wt. Caspase-3, -8 and -9 selective inhibitors confirmed that SGK-1 reduced the activation of caspase-dependent apoptosis, probably by both intrinsic and extrinsic pathways. In conclusion, we demonstrated that in kidney cells, overexpression of SGK-1 is protective against ceramide-induced apoptosis and the role of SGK-1 can be potentially explored as a therapeutic target in conditions like diabetes, where ceramide levels are increased.
Insights
Serum- and glucocorticoid-inducible protein kinase (SGK)-1 protects kidney cells from ceramide-induced apoptosis. This finding suggests SGK-1 as a potential therapeutic target for diabetes complications like nephropathy.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Ceramide is implicated in apoptosis, particularly in diabetes and its complications such as nephropathy.
- Serum- and glucocorticoid-inducible protein kinase (SGK)-1 is a known activator of cell survival pathways.
- Previous research indicated SGK-1's anti-apoptotic role in endothelial cells under high glucose conditions.
Purpose of the Study:
- To investigate the protective role of SGK-1 against ceramide-induced apoptosis in kidney cells.
- To elucidate the molecular mechanisms underlying SGK-1's potential protective effects.
Main Methods:
- Utilized human embryonic kidney (HEK)-293 cells stably transfected with wild-type (SGK-1wt) and dominant-negative (SGK-1dn) SGK-1.
- Induced apoptosis using C2-ceramide and TNF-α.
- Assessed apoptosis by measuring caspase-3 and Poly-ADP-ribose-polymerase-1 (PARP-1) cleavage.
- Investigated the involvement of PI3K, p38MAPK, and cAMP/PKA pathways using specific inhibitors.
Main Results:
- Overexpression of SGK-1 significantly reduced ceramide-induced apoptosis in HEK-293 cells.
- SGK-1 activation was associated with decreased caspase-3 and PARP-1 cleavage.
- SGK-1 levels increased in response to apoptotic stimuli, unlike AKT-1.
- The phosphoinositide-3-kinase (PI3K) pathway was identified as crucial for SGK-1-mediated protection.
- Inhibition of SGK-1 exacerbated TNF-α-induced apoptosis.
Conclusions:
- SGK-1 overexpression confers protection against ceramide-induced apoptosis in kidney cells.
- SGK-1 modulates apoptosis through caspase-dependent pathways, potentially involving both intrinsic and extrinsic routes.
- SGK-1 represents a promising therapeutic target for managing conditions characterized by elevated ceramide levels, such as diabetic nephropathy.
More Related Videos
15:43Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes
Published on: January 7, 2013
08:15Author Spotlight: Network Pharmacology and Molecular Docking to Decipher the Action of Jiawei Shengjiang San Against Diabetic Kidney Disease
Published on: May 10, 2024
Related Concept Videos
01:17The Extrinsic Apoptotic Pathway
01:24Caspases
01:30Acute Kidney Injury IV: Diagnostic Studies and Prevention
01:28Cells of the Innate Immune Response
Phagocytes
Phagocytes police the peripheral tissues by removing cellular debris and responding to the invasion of foreign substances or pathogens. Many phagocytes attack and remove microorganisms even before lymphocytes detect them. The human body has two general...