Cellular response to stress: autophagy

Update: Yoshinori Ohsumi’s 2016 Nobel Prize was for the study of autophagy. Hepatologist Mark Czaja, who came to Emory in 2015, is well known for his work on autophagy in the liver.

Feeling hungry? For this month’s Current Concept feature, lets take a look at the term autophagy. Taken literally, its Greek roots mean “self-digestion”.

Autophagy in mouse liver cells — the autophagic vesicles are green (Image from PNAS)

Autophagy is a basic response of cells to not having enough nutrients or other forms of stress: they begin to break down parts of the cell that are broken or not needed. The term autophagy was coined by Belgian biochemist Christian de Duve in the 1960s. He discovered lysosomes, the parts of the cell where breakdown can take place.

Autophagy comes up in many contexts in biomedical research. Indeed, there is an entire scientific journal devoted to the topic. At Emory, researchers interested in cancer, Parkinson’s, stroke and liver disease all have touched upon the process of autophagy. 

Autophagy can be triggered when cells Oakley Sunglasses cheap are producing proteins that are not folded correctly. For example, multiple myeloma cells are under particular stress because they derive from immune cells that are factories for secreting antibodies. Larry Boise and Sagar Lonial at Winship Cancer Institute have shown that multiple myeloma cells are vulnerable to attack via disruption of autophagy, which may be important for optimizing treatments.

Likewise, autophagy pops up in diseases such as Parkinson’s, in which clumps of misfolded proteins inside neurons are a feature of the disease. Zixu Mao and his colleagues have been interested in a distinct form of autophagy called chaperone-mediated autophagy, which seems to be impaired in Parkinson’s.

In contrast, Ling Wei and her colleagues in the Department of Anesthesiology are probing whether interfering with autophagy can soften the impact of stroke on the brain.

Frank Anania’s laboratory has been probing whether treatments for fatty liver disease can protect liver cells against fatty acid poisoning, through activation of autophagy.

Note: there has been some debate over whether autophagy can protect cells from dying in some situations, or whether there is autophagy-driven cell death. An expert on the various forms of cell death, Ed Mocarski, opines that “the jury is currently out on whether autophagy can be a precursor to a novel form of programmed cell death.”

 

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Quinn Eastman

Science Writer, Research Communications qeastma@emory.edu 404-727-7829 Office

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