Apoptosis is a tightly regulated pathway of programmed cell death where cells activate enzymes to degrade their own DNA and proteins. It occurs physiologically during development and to regulate cell populations, and pathologically due to DNA damage, protein misfolding, or infections. There are intrinsic and extrinsic pathways, both involving caspase enzyme activation. Dysregulation of apoptosis can contribute to diseases like cancer, autoimmune disorders, and neurodegeneration.

1. APOPTOSIS

2. Plan
1. Objectives
2. Definition
3. Causes
4. Mechanism
5. Morphology
6. Clinicopathological aspects
7. Summary

3. Objectives
Apoptosis is responsible for maintaining the regular
functions & activities of cells, the failure of which
may contribute the various clinical manifestations
like cancer, autoimmune disorders.

4. Definition
Apoptosis is a pathway of cell death that is induced
by a tightly regulated suicide program in which cell
destined to die activate intrinsic enzymes that degrade
the cells own nuclear DNA & nuclear and
cytoplasmic proteins.

5. Causes
1. Physiological
2. Pathological

6. Physiological Conditions
1. During embryogenesis
2. Involution of hormone dependent tissue upon
hormone withdrawal
3. Cell loss in proliferating cell populations
4. Acute inflammatory & immune response

7. Pathological Condition
1. DNA damage
2. Accumulation of misfolded proteins
3. Infections
4. Pathological atrophy in parenchymal organs after
duct obstruction

8. Mechanisms
1) The Intrinsic (Mitochondrial) Pathway
2) The Extrinsic (Death Receptor Initiated)
Pathway

9. • Caspase enzyme activation is important step
2 Phases
Initiation phase – Caspase become enzymatically
active
Execution phase – Caspase trigger the degradation of
critical cellular components

10. Anti-
apoptotic
Pro-apoptotic Sensors
1. BCL2
2. BCL-XL
3. MCL-1
1. BAX
2. BAK
1.Bad
2.Bim
3.Bid
4.Puma
5.Noxa

13. Morphological features
1. Cell shrinkage
2. Chromatin condensation
3. Formation of cytoplasmic blebs
4. Apoptotic bodies
5. Phagocytosis of apoptotic cells or cell
bodies

15. Clinicopathological Correlations
1. Growth Factor Deprivation
2. DNA damage
3. Protein misfolding
4. Apoptosis induced by the TNF Receptor Family
5. Cytotoxic T lymphocyte-mediated apoptosis

16. Disorders Associated with Dysregulated
Apoptosis
Defective apoptosis
- Cancer
- Autoimmune disorders
Increased apoptosis
- Neurodegenerative diseases
- Ischemic injury
- Death of virus-infected cells

17. Summary
1. Pathway of cell death
2. Suicidal programme
3. Physiological & Pathological condition
4. Two pathways
5. Clinical aspects