Can repeated flu infections raise the risk of Parkinson’s? Hyderabad study has clues

The recent study from scientist Swasti Raychaudhuri’s lab at CCMB explores how these RNA virus infections trigger molecular changes linked to neurodegeneration and identifies a molecular safeguard against this damage. However, while the study proposes that this mechanism “might contribute” to the development of Parkinson’s, it does not demonstrate that an infection ultimately causes Parkinson’s disease.

How Parkinson’s develops

In Parkinson’s disease, a protein called alpha-synuclein can become abnormally folded and start sticking together. Over time, these misfolded proteins form clumps called Lewy bodies, which accumulate inside nerve cells. These clumps can interfere with communication between neurons and affect how they function.
The study found out how an RNA virus could increase the formation of these clumps and accelerate the development of Parkinson’s disease.

How effective is the body’s defence?

Cells have a natural defence mechanism involving a protein called DDX39A. Normally, DDX39A is found in the nucleus, but when a viral infection occurs, it can move into the cell and interact with the virus’s RNA.

DDX39A can unwind the virus’s RNA, breaking apart the folded structures that the virus needs to replicate efficiently. As a result, the virus has more difficulty making new copies of itself, which reduces the amount of virus inside the cell. At the same time, this process appears to slow down the formation of alpha-synuclein clumps. In other words, DDX39A may help the cell fight the virus while also reducing the conditions that encourage abnormal alpha-synuclein aggregation.

Why then is the defence not a shield enough for Parkinson’s disease

The study suggests that there is a delicate balance inside infected cells. Sometimes the cell’s protective mechanisms can control both the virus and the abnormal protein changes. However, under certain conditions, viral infection may shift this balance and pace up the formation of protein clusters.

If these abnormal protein clumps accumulate in nerve cells over a long period, they could contribute to the cellular changes associated with Parkinson’s disease.

What researchers are investigating

The researchers are now studying how these changes might develop over a longer period. Their findings raise the possibility that repeated or severe viral infections could sometimes increase the risk of Parkinson’s. However, not every viral infection will lead to increased amyloid formation or Parkinson’s disease. Other factors in the cell and the individual’s biology also influence what happens after an infection.