A new FAU study shows astrocytes help neurons fire in sync, shaping brain rhythms key for attention, memory, and sleep – guiding how groups of neurons work together during high-focus or restful states.

New research strengthens the hypothesis that immune responses to central nervous system infections trigger amyloid-beta (Aβ) clumping. The work uses SARS-CoV-2 infection of human retinal tissue and retinal organoids as a model to investigate the potential antimicrobial origins of Alzheimer’s disease (AD). Research has implicated Aβ as a contributor to AD; an emergent theory suggests that the innate immune system produces aggregating Aβ to ensnare pathogens in the central nervous system – and that this pathway, over time and with repeat infections, could drive AD. Sean Miller and colleagues investigated this hypothesis by compiling tissue from 20 postmortem eyes from patients with AD to characterize Aβ accumulation. They then grew human retinal organoids based on stem cells from those tissues and exposed them to SARS-CoV-2. Miller et al. also evaluated postmortem eyes from patients with SARS-CoV-2 but without a history of AD. Ultimately, the analyses connected SARS-CoV-2 infection with immune cell-based Aβ extracellular clumping. Next, Miller et al. investigated whether preventing SARS-CoV-2 infection pharmacologically would preclude Spike 1 protein-mediated Aβ clustering. They did this by blocking the interaction between SARS-CoV-2 and the Neuropilin-1 protein, a recently recognized co-receptor for SARS-CoV-2 entry. Blocking the interaction reduced Aβ clustering in the human retinal tissue. “The accumulation of amyloid-β may be associated with the cognitive symptoms associated with COVID-19 and suggest that NRP1 inhibitors or antiviral medications may serve as therapeutic tools to prevent these consequences,” the authors write.

The research team led by Nobel Laureates May-Britt and Edvard Moser at the Norwegian University of Science and Technology (NTNU) is already known for their discovery of the brain’s sense of place. Now they have shown that the brain also weaves a tapestry of time: The brain segments and organizes events into experiences, placing unique bookmarks on them so that our lives don’t become a blurry stream, but rather a series of meaningful moments and memories we can revisit and learn from.