This document discusses various mechanisms of cell death, specifically necrosis and apoptosis. It describes the roles of caspases, cytochrome c, Bcl-2 family members, and other factors in apoptotic signaling pathways. It then discusses evidence of apoptosis in different neurodegenerative diseases like Alzheimer's, Parkinson's, Huntington's, and ALS. Various potential therapeutic targets and strategies aimed at inhibiting apoptosis are also outlined.
Apoptosis is an orderly process in which the cell's contents are packaged into small packets of membrane for “garbage collection” by immune cells. Apoptosis removes cells during development, eliminates potentially cancerous and virus-infected cells, and maintains balance in the body.
Cell cycle regulation presentation by me and my colleagues. Not the Best work but still it will give a general idea about DNA damage checkpoints, roles of Cdk-Cyclin complexes, Rb proteins, ATM&ATR kinases, p51, etc.
Reference : Nature reviews & The Cell a molecular approach. (cooper)
Content-
1. Background
2. Introduction
3. Difference between apoptosis and necrosis
4. Apoptosis in biologic processes
5. Apoptosis in pathologic processes
6. Morphologic features
7. Techniques to identify and count apoptotic cells
8. Biochemical changes
9. Molecular mechanism of apoptosis
10. Recent advancement and emerging trends in apoptosis
11. References
Apoptosis is an orderly process in which the cell's contents are packaged into small packets of membrane for “garbage collection” by immune cells. Apoptosis removes cells during development, eliminates potentially cancerous and virus-infected cells, and maintains balance in the body.
Cell cycle regulation presentation by me and my colleagues. Not the Best work but still it will give a general idea about DNA damage checkpoints, roles of Cdk-Cyclin complexes, Rb proteins, ATM&ATR kinases, p51, etc.
Reference : Nature reviews & The Cell a molecular approach. (cooper)
Content-
1. Background
2. Introduction
3. Difference between apoptosis and necrosis
4. Apoptosis in biologic processes
5. Apoptosis in pathologic processes
6. Morphologic features
7. Techniques to identify and count apoptotic cells
8. Biochemical changes
9. Molecular mechanism of apoptosis
10. Recent advancement and emerging trends in apoptosis
11. References
This is a final year project report on Ebola Virus Disease.....
.
.
.
for more information and materials for the project contact me @ www.facebook.com/abhishekurmate
Hi! I am Komal Sankaran, M.Sc. Biotechnology (Pune University Gold Medalist, 2013), CSIR-NET SPM fellow (Jun- 2014, 4th rank), CSIR-NET- LS (Dec 2013, 2nd rank), DBT JRF category- I. Please contact if anyone is interested in Life Sciences CSIR-NET coaching in Pune (Khadki area).
Email- komalsan91@gmail.com
CONCEPT OF NODOPATHIES AND PARANODOPATHIES.pptxNeurologyKota
emergence of autoimmune neuropathies and role of nodal and paranodal regions in their pathophysiology.
Peripheral neuropathies are traditionally categorized into demyelinating or axonal.
dysfunction at nodal/paranodal region key for better understanding of patients with immune mediated neuropathies.
antibodies targeting node and paranode of myelinated nerves have been increasingly detected in patients with immune mediated neuropathies.
have clinical phenotype similar common inflammatory neuropathies like Guillain Barre syndrome and chronic inflammatory demyelinating polyradiculoneuropathy
they respond poorly to conventional first line immunotherapies like IVIG
This presentation briefs out the approach of dementia assessment in line with consideration of recent advances. Now the pattern of assessment has evolved towards examining each individual domain rather than lobar assessment.
This presentation contains information about Dementia in Young onset. Also it describes the etiologies, clinical feature of common YOD & their management.
Entrapment Syndromes of Lower Limb.pptxNeurologyKota
This presentation contains information about the various Entrapment syndromes of Lower limb in descending order of topography. It also contains information about etiology, clinical features and management of each of these entrapment syndromes with special emphasis on electrodiagnostic confirmation.
2. 1.Necrosis
Follows acute ischemia or traumatic injury.
Occurs in most severely affected areas
Abrupt biochemical collapse lead to generation
of free radicals, excitotoxins.
Mitochondrial & nuclear swelling, dissolution of
organelles, condensation of chromatin around
nucleus.
Rupture of nuclear and cytoplasmic membranes
and degradation of DNA.
Extremely difficult to treat or prevent.
3. 2.Apoptosis
Programmed cell death
Seen in both acute and chronic neurologic
diseases.
After acute insults occurs in areas that are
not severely affected by injury.
Apoptosis occurs in penumbra, where
collateral blood flow reduces degree of
hypoxia.
Chronic neurodegenerative diseases it is
predominant form of cell death
4. Biochemical cascade activates proteases that
destroy molecules that are required for cell
survival.
Cytoplasm condenses, mitochondria and
ribosomes aggregate, nucleus condenses &
chromatin aggregates.
Cell fragments into “apoptotic bodies”
5. Chromosomal DNA is enzymatically cleaved
to 180-bp internucleosomal fragments.
Reduction in membrane potential of
mitochondria
Intracellular acidification
Generation of free radicals
Externalization of phosphatidylserine
residues
6. Death by Injury vs. Death by Suicide
(Necrosis vs. Apoptosis)
8. Exist as latent precursors.
Procaspases are composed of p10 and p20
subunits and an N-terminal recruitment
domain.
Active caspases are heterotetramers
consisting of two p10 and two p20 subunits
derived from two procaspase molecules
Have been categorized into upstream
initiators and downstream executioners
9. Upstream caspases are activated by cell-
death signal (e.g.TNFa)
Have a long N-terminal prodomain that
regulates their activation.
Upstream caspases activate downstream
caspases, which directly mediate events
leading to demise of cell.
Downstream caspases have short N-terminal
prodomain.
10. Upstream caspases subclassified into two
groups according to molecules modulating
their activation.
Procaspases 1,2,4,5,9,11,12,13 have long N-
terminal prodomain called caspase-recruiting
domain (CARD).
Caspases 8 and 10 have long N-terminal
prodomain called death-effector domain
(DED).
11. Caspases 2,8,9,10-initiators of apoptosis-
with a long prodomain
Caspases 1,4,5,11,12,13-cytokine activation
Caspases 3,6,7-effectors of apoptosis
Caspase 14-cytokine maturation
12. Upstream caspases activate in amplifying
cascade executioner caspases downstream.
Executioner caspases mediate cell death by
two main mechanisms: destruction and
activation.
13. Cytochrome c-member of the mitochondrial
electron-transport chain required for generation
of ATP.
Important trigger of caspase cascade.
Activation occurs by release of cytochrome c is
released from mitochondria into the cytoplasm.
Binds to Apaf-1 to form the apoptosome — a
molecular complex consisting of cytochrome c,
Apaf-1, ATP, and procaspase 9.
->Activates caspase 9, 30,52 -upstream initiator
of apoptosis.
14. Members of Bcl-2 family are proapoptotic or
antiapoptotic.
Balance between two has a crucial role in
release of cytochrome c
Members of caspase family can influence
balance of proapoptotic and antiapoptotic
signals.
For eg. caspase 8 and caspase 1 cleave Bid, a
member of Bcl-2 family, generating a
truncated fragment with proapoptotic activity.
15. Inhibitors interact directly with modulators of
cell death.
For Eg. X-linked inhibitor of apoptosis and
neuronal inhibitor of apoptosis are proteins
in neurons that directly inhibit caspase 3
activity and protect neurons from ischemic
injury.
16. P53 first arrests cell growth between G1 S
This allows for DNA repair during delay
If the damage is too extensive then p53
induces gene activation leading to apoptosis
(programmed cell death)
17.
18.
19.
20.
21. Important in normal physiology / development
– Development: Immune systems maturation,
Morphogenesis, Neural development
– Adult: Immune privilege, DNA Damage and wound
repair.
Excess apoptosis
– Neurodegenerative diseases
Deficient apoptosis
– Cancer
– Autoimmunity
22. Difference between acute and chronic
neurologic diseases is magnitude of stimulus
causing cell death.
Greater stimulus in acute diseases results in
both necrotic and apoptotic cell death
Milder insults in chronic diseases initiate
apoptotic cell death.
23. Activation of caspases1, 3, 8, 9, and 11 and release
of cytochrome c seen in cerebral ischemia,
Mice that express a dominant-negative caspase 1
construct or that are deficient in caspase 1 or caspase
11 have significant protection from ischemic injury.
Mice T/T with broad caspase inhibitor/semiselective
inhibitors of caspase 1 & 3 protect from ischemia.
Pattern of combined necrotic and apoptotic cell death
after ischemic or traumatic injury.
Necrotic cell death-core of infarction.
Ischemic penumbra-activate caspase cascade.
24. TBI-apoptosis-related changes in neurons
like presence of DNA strand breaks, caspase
activation, increased Bax, p53 expression.
Intraventricular administration of caspase-3
inhibitor z-DEVD-fmk before injury reduces
cell death and improves symptoms.
Mice expressing dominant-negative inhibitor
of caspase-1 show reduced brain damage
and free radical production after TBI.
25. Intraventricular infusion of NGF in rats
resulted in improved learning and memory
and decreased death of neurons in TBI.
Cyclosporin A protects against synaptic
dysfunction and cell death in rodent models
of TBI.
In rodents, SCI can be prevented by
glutamate-receptor antagonists.
26. Degenerating neurons show aggregates of
hyperphosphorylated tau protein & excessive
calcium-mediated proteolysis and oxidative
stress.
Increased DNA damage & caspase activity
Alterations in expression of apoptosis-related
genes such as Bcl-2 family members, Par- 4
and DNA damage response genes.
Marked decrease in expression of anti-
apoptotic gene called NCKAP1
27. Amyloid-β sensitizes neurons to death
involves membrane lipid peroxidation
Impairs function of membrane ionmotive
ATPases and glucose and glutamate
transporters resulting in membrane
depolarization, ATP depletion, excessive
calcium influx and mitochondrial dysfunction.
APP-substrate for caspase-3
Caspase-mediated cleavage of APP release a
carboxy-terminal peptide called C31, a
potent inducer of apoptosis
28. Presenilin-1 mutation leads to disturbances
in calcium homeostasis in endoplasmic
reticulum (ER) such that more calcium is
released in neurons.
Neurotrophic factors,cytokines known to
prevent neuronal apoptosis
29. Increased oxidative stress and mitochondrial
dysfunction in dopamine neurons are central
to disease.
Deficit in Mitochondrial Complex I which may
arise from or contribute to increased cellular
oxidative stress.
Environmental and genetic factors sensitizes
neurons to oxidative stress.
Monkeys and people exposed to toxin 1-
methyl-4-phenyl-1,2,3,6-tetrahydropyridine
(MPTP) show Parkinson’s-like symptoms
30. Apoptosis-related DNA damage and gene
activation seen in death of dopamine neurons
Levels of Par-4 are selectively increased
Suppression of Par-4 expression protects
dopamine neurons against death
Caspase-1 inhibition, glial cell-derived
neurotrophic factor (GDNF) can protect
dopamine neurons.
Expression of mutant α-synuclein in cultured
cells promotes apoptosis.
31. Impaired mitochondrial function and excitotoxic
death may be central to disease.
Studies of Lymphoblasts from patients with
Huntington’s disease showed increased stress
induced apoptosis associated with mitochondrial
dysfunction
Increased caspase-3 activation.
Mutant huntingtin in cultured cells induces caspase
8-dependent apoptosis.
Huntingtin can be cleaved by caspases, which may
promote protein aggregation and neurotoxicity.
Inhibition of caspase-1 was reported to slow disease
progression in mouse models.
32. Increased oxidative stress, overactivation of
glutamate receptors and cellular calcium overload.
Autoantibodies against voltage-dependent calcium
channels.
Mutations in antioxidant enzyme Cu/Zn-superoxide
dismutase (SOD)
Increased peroxidase activity.
In ALS DNA starts to fragment between nucleosomes
(a sign of nuclear apoptosis) in neurons within the
spinal-cord anterior horn and motor cortex.
Levels of Bax, but not Bcl-2, are increased in spinal-
cord motor neurons of ALS patients.
33.
34. Vitamin E, melatonin, resveratrol, carnosine,
coenzyme Q10
Vit E-slightly delays disease progression in
patients with moderately severe AD and PD
and can improve the cognitive function in AD
patients
Some clinical trials showed vitamin E actually
aggravated AD
35. Polyphenol with powerful antioxidant properties
Abundant component of red wine
May cause increased neuroprotective activity
through activation of sirtuin 1 (SIRT1)
SIRT1 exerts antiapoptotic and neuroprotective
effects by deacetylating transcription factors,
such as the tumour suppressor p53, the FOXO
family of proteins (also called FKHR, a member of
the Forkhead family of transcription factors), and
NF-B.
SIRT1 activation also has anti-aging properties in
invertebrates.
36. Radical scavenger, anti-apoptotic and anti-aging
properties.
Prevents mitochondrial calcium overload,
mitochondrial depolarization, ROS formation,
opening of mitochondrial permeability transition
pore (PTP) that precedes Cyt c release.
Clinical trial in PD patients, melatonin (3mg) did
not improve motor dysfunction abnormalities but
some beneficial effects noted in quality of sleep.
In AD patients-beneficial effects of melatonin (3
to 9 mg) on memory loss are unclear.
37. Clinical trials showed that combining
carnosine (daily dose of 1.5 g for 30 days)
with the conventional treatment for PD
significantly improves neurological status and
locomotor performance.
Could be used as an anti-aging treatment as
well as in AD treatment.
No clinical trials of using this drug in AD
No publication of data on the effects of
carnosine on cognitive function.
38. Cofactor of electron transport chain.
Prevents mitochondrial dysfunction
Antioxidant properties.
Evidence that it decreases with aging in both
human and rat tissues.
Cognitive performance of patients with AD
improved when treated with an antioxidant
together with acetylcholinesterase inhibitors.
Phase II clinical trials reports potentially
beneficial effects in CoQ10 in PD.
Ongoing research in HD, ALS, PSP.
39. Attenuate neurotoxicity in neuronal cell
preparations.
Temporarily rescue neurons since these
surviving neurons are in a dysfunctional state
due to release of pro-apoptotic proteins.
40. Two types of calpains u and m-calpain
Proteases when activated induce degradation of
cellular substrates such as cytoskeletal proteins,
membrane proteins, phosphatases.
Increased calpain immunoreactivity seen in senile
plaques of AD and PD brains.
P35->p25->activation of CDK5->
phosphorylation of myocyte enhancing
factor2(MEF-2)->apotosis.
CDK5 inhibitor roscovitine- antiapoptotic and
neuroprotective effects in several models of
neurodegeneration
41. Rodent and cell culture models calpain
inhibitors such as calpeptin, MDL-28170 and
PD150606 shown to prevent neuronal death
and restore cognitive function in AD models.
42. Ability to phosphorylate a variety of
substrates.
Lithium -direct & reversible GSK-3 inhibitor
Also inhibits calpain/CDK5 pathway &
modulates NMDA receptor.
Also favours autophagy.
Contradictory results in clinical trials in AD
and ALS.
43. Newer compounds-Paullones, indirubines,
thiazoles, aminopyrimidines and bisindol-
maleimides.
ATP inhibitors.
Developed by Glaxosmithkline and
AstraZeneca.
44. G1/S blockers-flavopiridol, kempaullone and
roscovitine showed neuroprotective
properties in neuronal cell cultures.
Anticancer drugs.
More side effects.
45. Anti-inflammatory properties, decreases
microglia activation, free radical formation,
prevent excessive intracellular calcium entry
via NMDA receptors.
Varied penetration via blood brain barrier
(atorvastatin, lovastatin)
Tried in PD, DLB, ALS, MS with varied results.
46. Mitigate mitochondrial calcium overload,
prevent ROS production, inhibit cyt c release,
increase in neurotrophin production
Daily ibuprofen (50 mg/kg) in APP23 AD mice
models and in humans caused increase in
cognitive activity
R-flurbiprofen –decreased learning
impairments in AD
Discouraging results in clinical trials.
47. Rosiglitazone, troglitazone-neuroprotective
effect against -amyloid-induced cell death.
Capacity to stop inflammatory gene
expression in peripheral immune cells
Reduced microglial and astrocyte activation.
Tried in AD, MS
48. Prevents release of proapoptotic
mitochondrial proteins such as cytochrome c
into the cytosol
Upregulates Bcl-2 expression
Reduces cleavage of Bid, a protein of the Bcl-
2 family with pro-apoptotic properties
Anti-inflammatory properties through
modulation of immune cytokines
Tried in AD,PD,HD,ALS
49. Calcium overload which leads to apoptotic
cell death
Memantine-uncompetitive NMDA receptor
antagonist that blocks with low affinity
Does not interfere with physiological activity
of glutamate in learning and memory
processes
Dizocilpine, selfotel, aptiganel,
remacemide,licostinel-unacceptable side
effects.
50. NGF role in maintenance of cholinergic
neurotransmitter systems in cholinergic forebrain
neurons
CERE-110 is a genetically engineered replication
defective adeno-associated virus serotype 2
(AAV2) vector
Contains full-length human -nerve growth factor
cDNA.
Phase II study in AD
BDNF may enhance differentiation and survival of
dopaminergic neurons in substantia nigra.
Several small molecules targeted to BDNF
receptors are being developed.
52. Apoptosis and Caspases in Neurodegenerative
Diseases: Robert M. Friedlander: N Engl J Med
348;14:april 3, 2003
Antiapoptotic drugs:A Therapeutic Strategy for the
Prevention of Neurodegenerative Diseases;Current
Pharmaceutical Design, 2011, Vol. 17, No. 3 233
Apoptosis In Neurodegenerative Disorders: Mark
P.Mattson; Nature Reviews | Molecular Cell Biology
Volume 1 | November 2000 | 121
53. Neuroprotection in Progressive Brain Disorders;
Ruth Djaldetti, Nirit Lev, Eldad Melamed; IMAJ . Vol
5 . August 2003
Gene Transfer of Baculoviral p35 by Adenoviral
Vector Protects Human Cerebral Neurons from
Apoptosis;DNA AND CELL BIOLOGY;Volume 23,
Number 8, 2004
Apoptotic and antiapoptotic mechanisms in stroke;
Cell Tissue Res (2000) 301:173–187
