Mechanisms of Cell Death

Transcription

1 Mechanisms of Cell Death CELL DEATH AND FORMATION OF THE SEMICIRCULAR CANALS Carol M. Troy August 25, 2008 FROM: Fekete et al., Development 124: 2451 (1997) PHENOMENOLOGY OF CELL DEATH I. DEVELOPMENT A. MORPHOGENESIS: SCULPTING/SHAPING STRUCTURES CREATION OF CAVITIES AND TUBES FUSION OF TISSUE MASSES (PALATE/NEURAL TUBE) CREATION OF FORM (DIGITS) PHENOMENOLOGY OF CELL DEATH: DEVELOPMENT B. DELETION OF UNNEEDED STRUCTURES KIDNEY: PRONEPHROS AND MESONEPHROS BRAIN: CORTICAL SUBPLATE NEURONS UROGENITAL SYSTEM: WOLFFIAN AND MÜLLERIAN DUCTS CELL DEATH AND FORMATION OF DIGITS PHENOMENOLOGY OF CELL DEATH: DEVELOPMENT C. ELIMINATION OF ECTOPIC, DAMAGED OR UNEEDED CELLS CELLS WITH DNA DAMAGE IMMUNE SYSTEM CELLS ECTOPIC CELLS FROM: Chen and Zhao, J. Exp. Zool. 282:691 (1998). 1

2 PHENOMENOLOGY OF CELL DEATH: DEVELOPMENT NEURONAL CULLING AS REGULATED BY COMPETITION FOR TARGET-SUPPLIED TROPHIC FACTOR D. CULLING: REGULATION OF CELL NUMBERS NERVOUS SYSTEM: MATCHING NEURONS WITH TARGETS MATCHING SCHWANN CELL AND OLIGODENDROCYTES WITH AXONS NORMAL DEVELOPMENTAL NEURONAL DEATH IS REGULATED BY TARGET DERIVED TROPHIC FACTORS NEURONAL CULLING AS REGULATED BY COMPETITION FOR TARGET-SUPPLIED TROPHIC FACTOR NEURON NUMBER IN CHICK ION 25,000 20,000 15,000 NORMAL 10,000 5,000 ENUCLEATED P2 P4 DEVELOPMENTAL STAGE Clarke, Rogers & Cowan J. Comp. Neurol. 167: 125 (1976) PHENOMENOLOGY OF CELL DEATH II. ELIMINATION OF CELLS WITH DNA DAMAGE III. DEFENSE FROM PATHOGENS IV. REGULATION OF CELL NUMBERS HOMEOSTASIS OF ORGAN/TISSUE SIZE PREVENTION OF UNREGULATED CELL GROWTH IMMUNE CELL NUMBERS 2

3 PHENOMENOLOGY OF CELL DEATH V. DISEASE A. CANCER B. HYPOXIC/ANOXIC CELL DEATH - Brain, heart C. NEURODEGENERATIVE DISORDERS - AD, PD D. ACUTE AND CHRONIC RENAL FAILURE E. VIRAL PATHOGENESIS PROPAGATION SIGNALING EVENTS TRANSCRIPTIONAL POST-TRANSCRIPTIONAL POST-TRANSLATIONAL APOPTOTIC DEATH vs NECROTIC DEATH PRESENT IN DEVELOPING TISSUES CYTOPLASMIC BLEBBING CELLULAR & NUCLEAR PYKNOSIS CHROMATIN CONDENSATION DNA DEGRADATION BY ENDONUCLEASES (FORMATION OF DNA LADDER) FORMATION OF MEMBRANE-LIMITED APOPTOTIC BODIES PHAGOCYTOSIS OF APOPTOTIC BODIES ABSENCE OF INFLAMMATORY RESPONSE RESPONSE TO CELL INJURY, TOXINS CELL & NUCLEAR SWELLING RANDOM DNA DEGRADATION LOSS OF MEMBRANE INTEGRITY & LOSS OF CYTOPLASMIC CONTENTS INFLAMMATORY RESPONSE EXECUTION CASPASES - DEATH PROTEASES Kerr, Wylie and Currie INITIATION DEATH STIMULI CELL DEATH Video decompressor 3

4 TIME LAPSE IMAGES OF A CELL UNDERGOING APOPTOSIS CASPASES - 2: EVIDENCE FOR ROLE IN APOPTOSIS OVER-EXPRESSION CAUSES APOPTOTIC DEATH ACTIVATED IN DYING CELLS CLEAVED FORMS DETECTABLE BY WESTERN & ANTIBODIES CAN MEASURE ACTIVITY IN DYING CELL EXTRACTS WITH SUBSTRATES BLOCK APOPTOTIC DEATH WITH CASPASE INHIBITORS REVERSIBLE AND IRREVERSIBLE PSEUDOSUBSTRATE PEPTIDES (zdevd-fmk) MOLECULAR INHIBITION: ANTISENSE, sirna VIRAL INHIBITORS: CRMA, p35 NULL ANIMALS SHOW DEFECTIVE CELL DEATH Phylogenetic Relations of Caspases EMBRYOGENIC DEFECTS IN A MOUSE LACKING CASPASE-9 Cell Death and DifferentiationLamkanfi et al. (2002) 9: From: Kuida et al Cell:94: , 1998 CASPASES - 1: PROPERTIES CASPASE - DEPENDENT ACTIVATION OF THE CAD ENDONUCLEASE EXECUTORS OF APOPTOTIC DEATH CYSTEINE PROTEASES CLEAVE AFTER ASP - ARE ASPARTASES APOPTOTIC STIMULUS CASPASE CAD ICAD CAD WHEN ACTIVATED, CLEAVE CELLULAR SUBSTRATES, LEADING TO APOPTOTIC DEATH DIFFERENT CASPASES DIFFER IN SPECIFICITY, MEANS OF ACTIVATION, AND SUBCELLULAR COMPARTMENTALIZATION 4

5 Bcl2 Proteins Caspase Regulation MITOCHONDRIA AND APOPTOTIC DEATH zymogen Apaf1 Casp9 XIAP Active caspase Diablo BCL2 mitochondrion BCL2 BAK Casp3/7 ciap1/2 HtrA2 CASPASE 3,6,7 ACTIVATION casp1/2 IAPS INHIBIT CASPASES AND APOPTOTIC DEATH INTRINSIC PATHWAY mitochondrial assembly of pro-apoptotic factors cytochrome c Apaf-1 APOPTOSOME pro-casp9 casp9 EXTRINSIC PA THWAY Death ligand delivered to death receptor DEATH INDUCING SIGNALING casp8 COMPLEX pro-casp8 BCL2mitochondrion XIAP pro-casp3 pro-casp7 casp3 casp7 FLIP CASPASE 3,7 ACTIVATION X Cleavage of substrates. APOPTOSIS ciap1,2 XIAP 5

6 Inhibitor of Apoptosis Proteins ROLE OF TRANSCRIPTION IN APOPTOSIS IN MANY, BUT NOT ALL PARADIGMS OF APOPTOTIC DEATH CELLS MUST SYNTHESIZE SPECIFIC GENES TO DIE THE PATHWAYS THAT REGULATE SUCH DEATH-ASSOCIATED GENES APPER TO OCCUR UPSTREAM OF MITOCHONDRIA - THAT IS, IN MANY PARADIGMS BLOCKADE OF TRANSCRIPTION THE MITOCHONDRIAL COMPONENT OF APOPTOSIS Verhagen et al. Genome Biol. 2: , 2001 SMAC/DIABLO INHIBITS IAPS TRANSCRIPTIONAL TARGETS OF P53 IN APOPTOSIS BCL2mitochondrion SMAC/DIABLO SIAH p53 CASPASE 3, 7 ACTIVATION X JNK/JUN BID PUMA NOXA APAF-1 OMI Cell specific Stimulus specific CASPASE 6 OMI/HTRA2 INHIBITS IAPS DEATH BY MURDER - RECEPTOR MEDIATED BCL2mitochondrion OMI/HTRA2 IN ADDITION TO SUICIDE (THE INTRINSIC APOPTOTIC MECHANISM), THERE IS ALSO A MAMMALIAN MECHANISM FOR MURDERING CELLS (THE EXTRINSIC APOPTOTIC PATHWAY) CASPASE 3,7 ACTIVATION X SER/THR PROTEASE THE EXTRINSIC APOPTOTIC PATHWAY IS REGULATED BY A SERIES OF SPECIFIC DEATH-PROMOTING RECEPTORS AND LIGANDS. OCCUPATION OF THESE RECEPTORS BRINGS ABOUT ACTIVATION OF PATHWAYS THAT CULMINATE IN CELL DEATH. 6

7 DEATH PROMOTING RECEPTORS AND LIGANDS FAS AND THE TRANSCRIPTIONAL REGULATION OF EXTRINSIC DEATH PATHWAY FAS-L LIGAND RECEPTOR p53 cjun FKH E2F NFKB FAS TNFα TNFαR1 FAS ligand TRAIL FAS TRAIL-R(DR-4 & DR-5) mitochondrion SMAC/DIABLO BCL2 BCL2 AIF CASPASE 3,6,7 ACTIVATION THE RECEPTOR-MEDIATED PATHWAY OF APOPTOTIC DEATH = DD = DED TNFα TNFR1 WHAT SIGNALS KEEP CELL FROM DYING? ACTIVATION OF AKT/PKB Growth factor FADD Y CASPASES 8,10 BID PI-3 kinase Y Y SHC Grb-2 PLCγ SOS tbid P- Akt MAPK Raf MEK Rsk Ras MITOCHONDRIAL PATHWAY CASPASE 3 Transcription AKT BLOCKS DEATH AT MULTIPLE LEVELS OF THE APOPTOTIC MECHANISM FAS-L p53 cjun FKH E2F NFKB FAS BLOCK APOPTOTIC TRANSC. PATHWAYS (FKH PHOSPHORYLATION) BAD BCLX-L BCL2mitochondrion SMAC AIF CASPASE 3,6,7 ACTIVATION ELEVATE ANTI-APOPTOTIC MOLECULES PHOSPHORYLATE, EXCLUDE PRO- APOPTOTIC BAD 7

8 PHENOMENOLOGY OF CELL DEATH V. DISEASE A. CANCER B. HYPOXIC/ANOXIC CELL DEATH - Brain, heart C. NEURODEGENERATIVE DISORDERS - AD, PD D. ACUTE AND CHRONIC RENAL FAILURE E. VIRAL PATHOGENESIS MECHANISMS OF APOPTOSIS RESISTANCE-3 INCREASED EXPRESSION OF BCL2 IN ALL, AML, CLL,MULTIPLE MYELOMA, PROSTATE CA, NEUROBLASTOMA DECREASED EXPRESSION OF IN COLON CA, BREAST CA MECHANISMS OF APOPTOSIS RESISTANCE-1 MUTATIONS OF CASPASES -MCF7 BREAST CA HAS NO CASPASE-3 EXPRESSION -DECREASED CASPASE-7 EXPRESSION IN COLON CA -HYPERMETHYLATION OF CASPASE-8 PROMOTER LOSS OF APAF-1 EXPRESSION IN MELANOMA STRATEGIES FOR TARGETING CANCER INHIBITION OF OVEREXPRESSED ANTI- APOPTOTIC MOLECULES -e.g. BCL2, BH3 PROTEINS, SURVIVIN, OTHER IAPS ENHANCE RECEPTOR MEDIATED DEATH VIA TRAIL-R ENHANCE PRO-APOPTOTIC PATHWAYS -small molecule mimetic of SMAC/Diablo MECHANISMS OF APOPTOSIS RESISTANCE-2 MAINTENANCE OF HOMEOSTASIS INCREASED EXPRESSION OF IAPS -SURVIVIN IN NEUROBLASTOMA -ciap1/2 IN LUNG CA -ciap1 IN ESOPHAGEAL SQUAMOUS CELL CA -ciap1 INCREASES RESISTANCE TO CHEMOTHERAPY TIGHT REGULATION OF DEATH PATHWAYS AT SEVERAL LEVELS IS ESSENTIAL A BETTER UNDERSTANDING OF THE MOLECULAR MECHANISM(S) OF APOPTOSIS WILL ENABLE DESIGN OF TARGETED THERAPIES FOR DISORDERS WITH DYSREGULATED CELL DEATH. -XIAP IN OVARIAN CA 8