COVID-19 may be linked to Parkinson’s disease, study finds

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Case reports of relatively young COVID-19 patients who developed Parkinson’s disease within weeks of contracting the virus have led scientists to wonder if there could be a link between the two conditions.

Scientists found that, at least in the test tube, the SARS-CoV-2 N-protein interacts with a neuronal protein called α-synuclein and speeds the formation of amyloid fibrils, pathological protein bundles that have been implicated in Parkinson’s disease.

In addition to respiratory symptoms, SARS-CoV-2 can cause neurological problems, such as loss of smell, headaches and “brain fog.”

However, whether these symptoms are caused by the virus entering the brain, or whether the symptoms are instead caused by chemical signals released in the brain by the immune system in response to the virus, is still unclear.

In Parkinson’s disease, a protein called α-synuclein forms abnormal amyloid fibrils, leading to the death of dopamine-producing neurons in the brain.

Interestingly, loss of smell is a common premotor symptom in Parkinson’s disease.

In the study, the team examined whether protein components of SARS-CoV-2 could trigger the aggregation of α-synuclein into amyloid.

They chose to study the two most abundant proteins of the virus: the spike (S-) protein that helps SARS-CoV-2 enter cells, and the nucleocapsid (N-) protein that encapsulates the RNA genome inside the virus.

In test tube experiments, the team showed that the N- and α-synuclein proteins interact directly with at least 3–4 copies of α-synuclein bound to each N-protein.

Compared to control cells with only α-synuclein injected, about twice as many cells died upon injection of both proteins.

Also, the distribution of α-synuclein was altered in cells co-injected with both proteins, and elongated structures were observed, although the researchers could not confirm that they were amyloid.

The team says it’s unknown whether these interactions also occur within neurons of the human brain, but if so, they could help explain the possible link between COVID-19 infection and Parkinson’s disease.

If you care about Parkinson’s disease, please read studies about foods that may reduce death risk in Parkinson’s disease, and new drugs show promise in slowing down Parkinson’s disease.

For more information about brain health, please see recent studies that common high blood pressure drugs may prevent Parkinson’s and dementia, and results showing people with Parkinson’s may benefit from 7 walking strategies.

The study was conducted by Christian Blum et al and published in ACS Chemical Neuroscience.

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