Autophagy is the name given to a collection of processes that recycle damaged cellular components and unwanted or harmful molecules. Materials flagged for recycling are engulfed by one of the cell's lysosomes and then dismantled inside it. Greater levels of autophagy are observed in a majority of the means of extending life in laboratory animals through genetic or metabolic manipulation to slow aging, including calorie restriction, in which the body reacts to low levels of nutrients, raw materials for protein manufacture in cells, by stepping up its efforts to reclaim the needed raw materials from existing structures that are past their prime.
The association of enhanced longevity and enhanced autophagy shouldn't be a surprise: aging is the accumulation of unrepaired damage, and autophagy is a process that attempts to minimize the present level of cellular damage before it can cause more harm. At some point the research community will make inroads towards creating therapies based on boosted autophagy - though this doesn't appear to be happening anywhere near as rapidly as I expected it to. Here is an example of research into the regulation of autophagy, similar to many other papers published in past years, but the expected use of this sort of knowledge to build a treatment has yet to happen:
The discovery of a gene network regulating lysosomal biogenesis and its transcriptional regulator transcription factor EB (TFEB) revealed that cells monitor lysosomal function and respond to degradation requirements and environmental cues. We report the identification of transcription factor E3 (TFE3) as another regulator of lysosomal homeostasis that induced expression of genes encoding proteins involved in autophagy and lysosomal biogenesis [in] response to starvation and lysosomal stress.We found that in nutrient-replete cells, TFE3 was recruited to lysosomes through interaction with active Rag guanosine triphosphatases (GTPases) and exhibited mammalian (or mechanistic) target of rapamycin complex 1 (mTORC1)-dependent phosphorylation. Phosphorylated TFE3 was retained in the cytosol through its interaction with the cytosolic chaperone 14-3-3. After starvation, TFE3 rapidly translocated to the nucleus and bound to the CLEAR (Coordinated Lysosomal Expression and Regulation) elements present in the promoter region of many lysosomal genes, thereby inducing lysosomal biogenesis.
Depletion of endogenous TFE3 entirely abolished the response [of] cells to starvation, suggesting that TFE3 plays a critical role in nutrient sensing and regulation of energy metabolism. Furthermore, overexpression of TFE3 triggered lysosomal exocytosis and resulted in efficient cellular clearance in a cellular model of a lysosomal storage disorder, Pompe disease, thus identifying TFE3 as a potential therapeutic target for the treatment of lysosomal disorders.
Link: http://dx.doi.org/10...isignal.2004754
View the full article at FightAging
