The significance of controlling the gene responsible for apoptosis phenomenon in age control
Apoptosis and cancer
The apoptosome cleaves the pro-caspase to its active form of caspase-9 , which in turn activates the effector caspase Mitochondria also release proteins known as SMACs second mitochondria-derived activator of caspases into the cell's cytosol following the increase in permeability of the mitochondria membranes. APAF-1 cells are protected from apoptosis stimuli such as irradiation. Third, drugs, such as cyclosporin, which stabilize mitochondrial membranes, have been shown to inhibit apoptosis 3 TNF path[ edit ] TNF-alpha is a cytokine produced mainly by activated macrophages , and is the major extrinsic mediator of apoptosis. Some apoptotic factors are vital during mitochondrial respiration e. To further complicate the matter, several endogenous cytosolic caspase inhibitors are present, such as XIAP, c-IAP1, and c-IAP2, which can inhibit activation of the caspase cascade 15 By suppressing viral budding, the researchers were able to trap the HIV virus in the cell and allow for the cell to undergo apoptosis natural cell death. This would clear damaged or preneoplastic cells from the body. But it is also possible that a programmed mechanism becomes activated with aging that triggers cell loss; future investigations will have to distinguish between these two possibilities. HIV decreases the production of molecules involved in marking the cell for apoptosis, giving the virus time to replicate and continue releasing apoptotic agents and virions into the surrounding tissue.
The members of the third group are a heterogeneous collection of proteins that share a BH3 domain; some are divergent homologues of Bcl-2 and Bax, such as Bid, whereas others are likely to possess a BH3 domain through convergent evolution For instance, treatments aim to restore apoptosis to treat diseases with deficient cell death, and to increase the apoptotic threshold to treat diseases involved with excessive cell death.
Early alterations include: Cell shrinkage and rounding occur because of the retraction lamellipodia and the breakdown of the proteinaceous cytoskeleton by caspases. A direct linear correlation between the age of the specimens and decrease in volume densities of the striated muscle cells was evident.
At the very least, release of cytochrome c interrupts the transfer of electrons between respiratory chain complexes III and IV, resulting in the generation of radical species that could accelerate apoptotic processes 18 19 Hyperactive apoptosis[ edit ] On the other hand, loss of control of cell death resulting in excess apoptosis can lead to neurodegenerative diseases, hematologic diseases, and tissue damage.
Another reactive nitrogen species with apoptotic effects is peroxynitrite. During apoptosis, DNA is cleaved at sites between nucleosomal units, thus generating DNA mononucleosomal and oligonucleosomal fragments bp multimers.
As a consequence, p53 cannot induce apoptosis, since it cannot induce the expression of proapoptotic proteins.
In Greek, apoptosis translates to the "falling off" of leaves from a tree. Cells may also die as direct consequences of viral infections. The degradation phase involves both cytoplasmic and nuclear events.
Why is apoptosis important
Recent studies have found that overexpressing p53 45 or treating cells with ceramide, a sphingolipid, will also generate reactive intermediates The free radical theory of aging proposed by Harman links senescence to damage inflicted by superoxide-derived radicals and other reactive intermediates generated primarily in mitochondrial respiration 63 64 A remarkable feature of these KO mice is that they have a very restricted phenotype: Casp3, 9, APAF-1 KO mice have deformations of neural tissue and FADD and Casp 8 KO showed defective heart development, however in both types of KO other organs developed normally and some cell types were still sensitive to apoptotic stimuli suggesting that unknown proapoptotic pathways exist. Functional declines, such as normal age-associated memory loss, are more likely a result of subtle molecular changes. Indeed cell death contributes to tissue homeostasis by balancing mitosis and pathology can derive from both its increase or decrease. HIV decreases the production of molecules involved in marking the cell for apoptosis, giving the virus time to replicate and continue releasing apoptotic agents and virions into the surrounding tissue. In addition, after embryonic day
Methods for distinguishing apoptotic from necrotic necroptotic cells[ edit ] In order to perform analysis of apoptotic versus necrotic necroptotic cells, one can do analysis of morphology by time-lapse microscopyflow fluorocytometryand transmission electron microscopy. Moreover, its Fas-binding domain is an inhibitor of Fas-induced apoptosis
A remarkable feature of these KO mice is that they have a very restricted phenotype: Casp3, 9, APAF-1 KO mice have deformations of neural tissue and FADD and Casp 8 KO showed defective heart development, however in both types of KO other organs developed normally and some cell types were still sensitive to apoptotic stimuli suggesting that unknown proapoptotic pathways exist. Associate Professor Mikako Fujita has stated that the approach is not yet available to HIV patients because the research team has to conduct further research on combining the drug therapy that currently exists with this "Lock-in and apoptosis" approach to lead to complete recovery from HIV. Surrounding cells or macrophages subsequently phagocytose apoptotic bodies. Cells may also die as direct consequences of viral infections. These data strongly suggest that apoptosis may be more prevalent than necrosis in very old rats, and interventions to attenuate this loss could benefit cardiac health. Although many of the key apoptotic proteins have been identified, the molecular mechanisms of action or inaction of these proteins remain to be elucidated. Recent studies have found that overexpressing p53 45 or treating cells with ceramide, a sphingolipid, will also generate reactive intermediates
based on 82 review