TNF-α-mediated cardiorenal injury after rhabdomyolysis in rats.
The TNF-α serum level increases after rhabdomyolysis and is involved in the subsequent cardiorenal injury. In the present study, we investigated the TNF-α-dependent cell signaling pathways implicated in cellular injury in these organs. Rhabdomyolysis was induced by intramuscular glycerol injection in rats. Renal function, cardiac and renal pathology, and activation of caspases were evaluated during the first 24 h after glycerol injection. TNF-α blockade with infliximab reduced tubular necrosis and cardiorenal apoptosis. Cellular Fas-associated protein with death domain-like IL-1β-converting enzyme inhibitory protein (cFLIP), an inhibitor of caspase-8, was overexpressed in the kidney but not in the heart. The inhibitory effect of cFLIP blunted caspase-8 activation in the kidney. In this condition, the cellular response to the TNF-α stimulus was driven to receptor-interacting protein-1 (RIP1)-mediated necroptosis. Treatment with RIP1 inhibitor (necrostatin-1) isolated or in combination with infliximab showed a similar reduction in tubular necrosis, underscoring the importance of TNF-α-mediated tubular necroptosis in this model. TNF-α played a positive regulatory role in the transcription of proapoptotic Bax and p53-upregulated modulator of apoptosis (PUMA) proteins. Infliximab treatment reduced caspase-9-mediated apoptosis in both organs. Treatment with a caspase-8 inhibitor showed that caspase-8 participated in the process of apoptosis only in the heart, upstream of caspase-9 activation. TNF-α-mediated necroptosis is the predominant form of tubular injury observed in the glycerol model. TNF-α up regulates Bax and PUMA proapoptotic proteins, resulting in activation of the intrinsic pathway of apoptosis in the kidney and heart.
Division of Nephrology, Department of Medicine, School of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil ehomsi@aclnet.com.br.
Eduardo
E
Homsi
Division of Nephrology, Department of Medicine, School of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
Diego Duarte
DD
Andreazzi
Division of Nephrology, Department of Medicine, School of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
Jose Butori Lopes de
JB
Faria
Division of Nephrology, Department of Medicine, School of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
Patrícia
P
Janino
D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D061945:Caspase Inhibitors / Q000494:pharmacology*; D004195:Disease Models, Animal; D008297:Male; D009336:Necrosis / Q000378:metabolism; D017208:Rats, Wistar; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism; D012206:Rhabdomyolysis / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; D061945:Caspase Inhibitors; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D053181:Caspase 8; D053453:Caspase 9
acute kidney injury; apoptosis; cardiac injury; necroptosis; rhabdomyolysis; tumor necrosis factor-α