Apoptosis
Define Apoptosis
Pathway of cell death induced by a tightly regulated suicide program
Cells are destined to die activate intrinsic enzymes that degrade cells’ own
nuclear DNA, nuclear and cytoplasmic proteins
Characteristics of Apoptosis
Important mode of cell death
Apoptotic cells break up into fragments
Apoptotic bodies
Plasma membrane remains intact but structure is altered
Become ‘tasty’ targets for phagocytosis
Does not elicit inflammatory reaction
Programmed cell death
Occurs normally in physiological reactions
When cell are damaged beyond repair
Damage effects cells’ DNA
Apoptosis 1
, Causes of Apoptosis
Physiological
Programmed destruction of cells during embryogenesis
Implantation
Organogenesis
Development involution
Metamorphosis
Hormone dependent involution in adult
Endometrial cells break down during menstrual cycle
Cell loss in proliferating cell population
Intestinal crypt epithelium (homeostasis)
Elimination of potentially harmful self-reactive lymphocytes
To prevent reactions against one’s own tissue
Death of neutrophils in an acute inflammation response and lymphocytes
at the end of an immune response
Cells undergo apoptosis
Deprived of necessary survival signals - growth factors
Pathological
DNA damage
Damages DNA directly or via production of free radicals
Radiation
Cytotoxic anticancer drugs
Hypoxia
Accumulation of misfold proteins
Apoptosis 2
Define Apoptosis
Pathway of cell death induced by a tightly regulated suicide program
Cells are destined to die activate intrinsic enzymes that degrade cells’ own
nuclear DNA, nuclear and cytoplasmic proteins
Characteristics of Apoptosis
Important mode of cell death
Apoptotic cells break up into fragments
Apoptotic bodies
Plasma membrane remains intact but structure is altered
Become ‘tasty’ targets for phagocytosis
Does not elicit inflammatory reaction
Programmed cell death
Occurs normally in physiological reactions
When cell are damaged beyond repair
Damage effects cells’ DNA
Apoptosis 1
, Causes of Apoptosis
Physiological
Programmed destruction of cells during embryogenesis
Implantation
Organogenesis
Development involution
Metamorphosis
Hormone dependent involution in adult
Endometrial cells break down during menstrual cycle
Cell loss in proliferating cell population
Intestinal crypt epithelium (homeostasis)
Elimination of potentially harmful self-reactive lymphocytes
To prevent reactions against one’s own tissue
Death of neutrophils in an acute inflammation response and lymphocytes
at the end of an immune response
Cells undergo apoptosis
Deprived of necessary survival signals - growth factors
Pathological
DNA damage
Damages DNA directly or via production of free radicals
Radiation
Cytotoxic anticancer drugs
Hypoxia
Accumulation of misfold proteins
Apoptosis 2
