Autophagy protects renal tubular cells against cyclosporine toxicity.
A major side effect of the powerful immunosuppressive drug cyclosporine (CsA) is the development of a chronic nephrotoxicity whose mechanisms are not fully understood. Recent data suggest that tubular cells play a central role in the pathogenesis of chronic nephropathies. We have shown that CsA is responsible for endoplasmic reticulum (ER) stress in tubular cells. Autophagy has recently been described to be induced by ER stress and to alleviate its deleterious effects. In this study, we demonstrate that CsA induces autophagy in primary cultured human renal tubular cells through LC3II expression and autophagosomes visualization by electron microscopy. Autophagy is dependant on ER stress because various ER stress inducers activate autophagy, and salubrinal, an inhibitor of eIF2alpha dephosphorylation that protects cells against ER stress, inhibited LC3II expression. Furthermore, autophagy inhibition during CsA treatment with beclin1 siRNA significantly increases tubular cell death. Finally, immunohistochemical analysis of rat kidneys demonstrates a positive LC3 staining on injured tubular cells, suggesting that CsA induces autophagy in vivo. Taken together, these results demonstrate that CsA, through ER stress induction, activates autophagy as a protection against cell death.
Pallet
Nicolas
N
INSERM U775, Centre Universitaire des Saints-Pères, Université Paris Descartes, Paris, France. nicolas.pallet@univ-paris5.fr
Bouvier
Nicolas
N
Legendre
Christophe
C
Gilleron
Jerome
J
Codogno
Patrice
P
Beaune
Philippe
P
Thervet
Eric
E
Anglicheau
Dany
D
D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D001343:Autophagy / Q000502:physiology*; D000071186:Beclin-1; D015415:Biomarkers / Q000378:metabolism; D002478:Cells, Cultured; D016572:Cyclosporine / Q000633:toxicity*; D019610:Cytoprotection / Q000187:drug effects*; D004721:Endoplasmic Reticulum / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007166:Immunosuppressive Agents / Q000633:toxicity*; D007684:Kidney Tubules / Q000166:cytology* / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D019284:Thapsigargin / Q000378:metabolism; D000091342:Endoplasmic Reticulum Chaperone BiP
D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D015415:Biomarkers; D016572:Cyclosporine; D004791:Enzyme Inhibitors; D006360:Heat-Shock Proteins; D007166:Immunosuppressive Agents; D008565:Membrane Proteins; D018832:Molecular Chaperones; D034741:RNA, Small Interfering; D019284:Thapsigargin; C491997:BECN1 protein, human; C051684:GRP78 protein, rat; D000091342:Endoplasmic Reticulum Chaperone BiP