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.

Pastore, D., DELLA MORTE, D., Coppola, A., Capuani, B., Lombardo, M.f., Pacifici, F., et al. (2015). SGK-1 protects kidney cells against apoptosis induced by ceramide and TNF-α. CELL DEATH & DISEASE, 6 [10.1038/cddis.2015.232].

SGK-1 protects kidney cells against apoptosis induced by ceramide and TNF-α

PASTORE, DONATELLA;DELLA MORTE, DAVID;CAPUANI, BARBARA;LOMBARDO, MARCO FELICE;FEDERICI, MASSIMO;BELLIA, ALFONSO;DI DANIELE, NICOLA;TESAURO, MANFREDI;DONADEL, GIULIA;SBRACCIA, PAOLO;LAURO, DAVIDE
2015-09-17

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.
17-set-2015
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore MED/13 - ENDOCRINOLOGIA
Settore MED/09 - MEDICINA INTERNA
Settore MED/49 - SCIENZE TECNICHE DIETETICHE APPLICATE
Settore MED/04 - PATOLOGIA GENERALE
English
Con Impact Factor ISI
INSULIN, CERAMIDE, DIABETES MELLITUS, TNF ALPHA, APOPTOSIS
Pastore, D., DELLA MORTE, D., Coppola, A., Capuani, B., Lombardo, M.f., Pacifici, F., et al. (2015). SGK-1 protects kidney cells against apoptosis induced by ceramide and TNF-α. CELL DEATH & DISEASE, 6 [10.1038/cddis.2015.232].
Pastore, D; DELLA MORTE, D; Coppola, A; Capuani, B; Lombardo, Mf; Pacifici, F; Ferrelli, F; Arriga, R; Mammi, C; Federici, M; Bellia, A; DI DANIELE, N; Tesauro, M; Donadel, G; Noto, D; Sbraccia, P; Sconocchia, G; Lauro, D
Articolo su rivista
File in questo prodotto:
File Dimensione Formato  
SGK-1.pdf

solo utenti autorizzati

Licenza: Copyright dell'editore
Dimensione 2.03 MB
Formato Adobe PDF
2.03 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/117508
Citazioni
  • ???jsp.display-item.citation.pmc??? 8
  • Scopus 24
  • ???jsp.display-item.citation.isi??? 22
social impact