What COVID-19 can teach us about Alzheimer's and Parkinson's Disease

Can a viral infection influence the development of diseases such as Alzheimer's or Parkinson's? And can signs of those changes be detected in a simple blood sample? These are the questions that researcher Gunjan Bawne investigates every day at BPRC. Recently, she published her findings on this topic in the Journal of Extracellular Vesicles. 

In the publication, the researchers describe how tiny particles in the blood may play an important role in the relationship between COVID-19 and neurodegenerative diseases. “It's actually a very new field of research,” Gunjan says enthusiastically. “That's exactly what makes it so interesting. There is still so much we don't know.” 

From India to the Netherlands 

Gunjan's scientific journey began in India, where she studied bioengineering. Over time, however, her interest shifted increasingly toward the human body and the brain. 

“I've always been curious about how everything works,” she says. “Why do diseases develop? How do cells communicate with each other? Those kinds of questions fascinated me.” 

She moved to the Netherlands to pursue a Master's degree in Neuroscience at Vrije Universiteit Amsterdam. She has now lived here for almost five years. Looking back, she describes the move as a major leap into the unknown. 

“It really was a leap of faith,” she says. “But I quickly felt this was the right place for me.” 

“I really love the research culture here,” she continues. “People are open, supportive, and there's a lot of collaboration. It's easy to walk into another researcher's office to discuss ideas or learn new techniques.” 

On a personal level, too, she feels at home in the Netherlands. “I feel that I can live my life here the way I want to,” she says. “That means a lot to me.” 

Tiny messengers from the brain 

Gunjan also quickly found her place at BPRC. “We have a very international research group,” she says. “And because our research field is still developing rapidly, we help each other a lot. I've really been involved in establishing new techniques and experimental models here.” 

Although much of her research relies on human stem cells and other in vitro models, she also understands why studies involving non-human primates are sometimes essential. “These models allow us to follow biological processes over a much longer period of time. In humans, it's simply impossible to observe exactly what happens inside the body month after month following an infection.” 

For her research, blood samples collected from SARS-CoV-2-infected non-human primates are analysed over extended periods. “This enables us to monitor changes that are almost impossible to study in people in this way. We're trying to understand which biological processes may contribute to Alzheimer's or Parkinson's disease, and whether we might eventually be able to detect those changes much earlier.” 

She believes that different research approaches complement one another. “I work extensively with in vitro models and human stem cells. But sometimes you also need models in which you can study the complete immune system and the interactions between different organs. That's what makes this research so valuable.” 

Gunjan's research focuses on extracellular vesicles: microscopic particles released by cells. These vesicles transport biological information throughout the body and can even travel from the brain into the bloodstream. 

“They're essentially tiny messengers,” Gunjan explains. “By studying these vesicles, we hope to better understand what happens in the brain after a viral infection.” 

The researchers investigated microRNAs—small molecules that regulate gene activity—and compared data from COVID-19, Alzheimer's disease, and Parkinson's disease to identify overlapping biological patterns. 

“We found that certain dysregulated microRNAs appear in both COVID-19 and neurodegenerative diseases. That doesn't mean COVID directly causes Alzheimer's disease, but it does help us better understand which biological processes may be involved.” 

“We're trying to place the data into a biological context. Not just identifying molecules, but understanding what those changes actually do inside the body.” 

Research with stem cells 

In addition to analysing patient data, Gunjan also works with advanced in vitro models based on human stem cells. These are differentiated into neurons, astrocytes, and microglia to study how viral proteins and inflammatory responses affect brain cells. 

“Even after the virus itself has disappeared, inflammatory responses or viral proteins may continue to have effects. We want to understand what that long-lasting disruption does to the brain.” 

“Alzheimer's and Parkinson's disease have an enormous societal impact. The better we understand the biological processes that contribute to these diseases, the better we can ultimately think about treatments or ways to detect them at an earlier stage.” 

“If I find something fascinating, I go all in” 

“I'm simply a very enthusiastic person,” she says with a laugh. “If I find something fascinating, I go all in.” 

That curiosity ultimately brought her to the Netherlands, into neuroscience, and to this field of research. She hopes to continue exploring the relationship between viral infections and neurodegenerative diseases. 

“There is still so much we don't understand. That's exactly what makes it so exciting.”