Autophagy is the process of dealing with the body's harmful "garbage". The body produces many wastes every day, such as some accumulated proteins. In order to make the structure and function of human cells normal, these "garbage" needs a mechanism to eliminate. If this mechanism is blocked, waste products accumulate in the cells, eventually leading to disease in the body. As cells age, their ability to expel harmful waste decreases, according to a new study from Duke University's institute of medical research. The findings suggest that the deterioration of autophagy in older neurons may be a risk factor for a range of neurodegenerative diseases, such as Alzheimer's and Parkinson's.
"Reduced autophagy makes neurons more susceptible to genetic or environmental risks," holtzbauer says. "Neurodegenerative diseases associated with worsening autophagy, such as Alzheimer's, Huntington's and Parkinson's, are the main areas of interest."
The mechanism of autophagy is that the autophagosome first binds to misfolded proteins and processes these wastes in the first step. Then, the autophagosomes that contain human waste bind to lysosomes, and the enzymes in the lysosomes degrade the waste. This degradation mechanism is the main way to keep neurons healthy, without which they eventually die from the accumulation of waste.
Through a series of studies of mice, the team showed that while the early stages of autophagosome formation were unaffected, they found that older mice had defects in their autophagosomes that could allow garbage to accumulate at synapses, causing neurons to receive or transmit signals that were interrupted or stopped. Holtzbauer points out that in other studies of the same type, researchers have found defective autophagosomes in the tissues of dead people with neurodegenerative diseases.
This provides further evidence that autophagosomes may play an important role in human neurodegenerative diseases, a finding that needs to be confirmed by more precise data.