Nav: Home

Zika virus infects the adult human brain and causes memory deficits in animal models

September 05, 2019

Zika virus attracted worldwide attention in recent years due to the devastating consequences of infection for pregnant women and their fetuses, many of which were born with microcephaly and other severe neurological malformations. Although ZIKV infection has historically been associated to relatively mild symptoms, a number of serious neurological complications were described in adult patients during the 2015 outbreak in America. Despite these clinical observations, how ZIKV is toxic to the adult brain and how neurological problems are caused in infected adults have remained unknown.

Researchers led by neuroscientists Sergio T. Ferreira e Claudia Figueiredo and virologist Andrea Da Poian at the Federal University of Rio de Janeiro (Brazil) have now come up with answers to these questions. First, they exposed small fragments of adult human brain tissue to ZIKV isolated from the blood of an infected Brazilian patient. Contrary to the previous belief that ZIKV only infects neuronal progenitor cells or neurons that are still immature in the developing brain, they found that the virus infected and replicated in adult human tissue, producing new viral particles capable of infecting more cells.

But what are the consequences of this infection? To address this question, they injected Zika virus directly into the brains of mice. As lead author Claudia P. Figueiredo and Ferreira explains: "Infected mice exhibited marked memory impairment that persisted even after infection had been fought off by the organism. Moreover, this was consistent with the fact that brain regions responsible for learning and memory processing were the main sites of viral replication in their brains."

The work further showed that infection by ZIKV causes a strong inflammatory response in the mouse brain, and this includes activation of brain resident immune cells called microglia. Fernanda Barros-Aragão, a PhD student and author of the study, explains that this exaggerated inflammatory response is ultimately responsible for memory loss: "Neurons communicate through highly specialized regions called synapses. Surprisingly, we found that microglia that become aberrantly activated upon infection by ZIKV attack and engulf synapses. This impairs communication between neurons and, therefore, the formation of new memories." Interestingly, when animals were treated for about one week with anti-inflammatory drugs capable of blocking microglial activation, they recovered memory.

Results from this study indicate that the adult brain is damaged by infection by ZIKV, and point to the need to carefully evaluate learning and memory performance in follow-up assessments of infected adults. Although no specific treatments for ZIKV infection are yet available, these findings further reveal the possibility that neurological symptoms caused to infection by controlling brain inflammation.
-end-
The paper entitled "Zika virus replicates in adult human brain tissue and impairs synapse function and memory in adult mice" will be published in Nature Communications on the 5th of September.

The study was funded by the Carlos Chagas Filho Foundation for Research Support in the State of Rio de Janeiro (FAPERJ), the National Council for Scientific and Technological Development (CNPq), the Coordination for the Improvement of Higher Education Personnel, Ministry of Education (CAPES / MEC), the Funding Agency for Studies and Projects (FINEP), the National Institute of Science and Technology for Structural Biology and Bioimaging (INBEB), the National Institute for Innovation in Pharmaceutical Products and Identification of New Therapeutic Targets (INOVAMED), and the National Institute of Science and Technology for Translational Neuroscience (INNT).

Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem (INBEB)

Related Neurons Articles:

How do we get so many different types of neurons in our brain?
SMU (Southern Methodist University) researchers have discovered another layer of complexity in gene expression, which could help explain how we're able to have so many billions of neurons in our brain.
These neurons affect how much you do, or don't, want to eat
University of Arizona researchers have identified a network of neurons that coordinate with other brain regions to influence eating behaviors.
Mood neurons mature during adolescence
Researchers have discovered a mysterious group of neurons in the amygdala -- a key center for emotional processing in the brain -- that stay in an immature, prenatal developmental state throughout childhood.
Astrocytes protect neurons from toxic buildup
Neurons off-load toxic by-products to astrocytes, which process and recycle them.
Connecting neurons in the brain
Leuven researchers uncover new mechanisms of brain development that determine when, where and how strongly distinct brain cells interconnect.
More Neurons News and Neurons Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...