The proteases HtrA2/Omi and UCH-L1 regulate TNF-induced necroptosis

TY - JOUR

T1 - The proteases HtrA2/Omi and UCH-L1 regulate TNF-induced necroptosis

AU - Sosna, Justyna

AU - Voigt, Susann

AU - Mathieu, Sabine

AU - Kabelitz, Dieter

AU - Trad, Ahmad

AU - Janssen, Ottmar

AU - Meyer-Schwesinger, Catherine

AU - Schütze, Stefan

AU - Adam, Dieter

PY - 2013/1/1

Y1 - 2013/1/1

N2 - BACKGROUND: In apoptosis, proteolysis by caspases is the primary mechanism for both initiation and execution of programmed cell death (PCD). In contrast, the impact of proteolysis on the regulation and execution of caspase-independent forms of PCD (programmed necrosis, necroptosis) is only marginally understood. Likewise, the identity of the involved proteases has remained largely obscure. Here, we have investigated the impact of proteases in TNF-induced necroptosis.RESULTS: The serine protease inhibitor TPKC protected from TNF-induced necroptosis in multiple murine and human cells systems whereas inhibitors of metalloproteinases or calpain/cysteine and cathepsin proteases had no effect. A screen for proteins labeled by a fluorescent TPCK derivative in necroptotic cells identified HtrA2/Omi (a serine protease previously implicated in PCD) as a promising candidate. Demonstrating its functional impact, pharmacological inhibition or genetic deletion of HtrA2/Omi protected from TNF-induced necroptosis. Unlike in apoptosis, HtrA2/Omi did not cleave another protease, ubiquitin C-terminal hydrolase (UCH-L1) during TNF-induced necroptosis, but rather induced monoubiquitination indicative for UCH-L1 activation. Correspondingly, pharmacologic or RNA interference-mediated inhibition of UCH-L1 protected from TNF-induced necroptosis. We found that UCH-L1 is a mediator of caspase-independent, non-apoptotic cell death also in diseased kidney podocytes by measuring cleavage of the protein PARP-1, caspase activity, cell death and cell morphology. Indicating a role of TNF in this process, podocytes with stably downregulated UCH-L1 proved resistant to TNF-induced necroptosis.CONCLUSIONS: The proteases HtrA2/Omi and UCH-L1 represent two key components of TNF-induced necroptosis, validating the relevance of proteolysis not only for apoptosis, but also for caspase-independent PCD. Since UCH-L1 clearly contributes to the non-apoptotic death of podocytes, interference with the necroptotic properties of HtrA2/Omi and UCH-L1 may prove beneficial for the treatment of patients, e.g. in kidney failure.

AB - BACKGROUND: In apoptosis, proteolysis by caspases is the primary mechanism for both initiation and execution of programmed cell death (PCD). In contrast, the impact of proteolysis on the regulation and execution of caspase-independent forms of PCD (programmed necrosis, necroptosis) is only marginally understood. Likewise, the identity of the involved proteases has remained largely obscure. Here, we have investigated the impact of proteases in TNF-induced necroptosis.RESULTS: The serine protease inhibitor TPKC protected from TNF-induced necroptosis in multiple murine and human cells systems whereas inhibitors of metalloproteinases or calpain/cysteine and cathepsin proteases had no effect. A screen for proteins labeled by a fluorescent TPCK derivative in necroptotic cells identified HtrA2/Omi (a serine protease previously implicated in PCD) as a promising candidate. Demonstrating its functional impact, pharmacological inhibition or genetic deletion of HtrA2/Omi protected from TNF-induced necroptosis. Unlike in apoptosis, HtrA2/Omi did not cleave another protease, ubiquitin C-terminal hydrolase (UCH-L1) during TNF-induced necroptosis, but rather induced monoubiquitination indicative for UCH-L1 activation. Correspondingly, pharmacologic or RNA interference-mediated inhibition of UCH-L1 protected from TNF-induced necroptosis. We found that UCH-L1 is a mediator of caspase-independent, non-apoptotic cell death also in diseased kidney podocytes by measuring cleavage of the protein PARP-1, caspase activity, cell death and cell morphology. Indicating a role of TNF in this process, podocytes with stably downregulated UCH-L1 proved resistant to TNF-induced necroptosis.CONCLUSIONS: The proteases HtrA2/Omi and UCH-L1 represent two key components of TNF-induced necroptosis, validating the relevance of proteolysis not only for apoptosis, but also for caspase-independent PCD. Since UCH-L1 clearly contributes to the non-apoptotic death of podocytes, interference with the necroptotic properties of HtrA2/Omi and UCH-L1 may prove beneficial for the treatment of patients, e.g. in kidney failure.

KW - Animals

KW - Apoptosis

KW - Cells, Cultured

KW - HT29 Cells

KW - Humans

KW - Jurkat Cells

KW - Mice

KW - Mitochondrial Proteins

KW - NIH 3T3 Cells

KW - Podocytes

KW - Rats

KW - Rats, Wistar

KW - Serine Endopeptidases

KW - Tumor Necrosis Factor-alpha

KW - Ubiquitin Thiolesterase

U2 - 10.1186/1478-811X-11-76

DO - 10.1186/1478-811X-11-76

M3 - SCORING: Journal article

C2 - 24090154

VL - 11

SP - 76

JO - CELL COMMUN SIGNAL

JF - CELL COMMUN SIGNAL

SN - 1478-811X

ER -