Cellular reprogramming helps outsmart progressive Alzheimers disease

A team led by researcher José Vicente Sánchez Mut at the Institute for Neurosciences (IN), a joint center of the Spanish National Research Council (CSIC) and the Miguel Hernández University of Elche (UMH), together with researcher Johannes Gräff at the École Polytechnique Fédérale de Lausanne (EPFL), has identified an experimental molecule capable of "reprogramming" the brain's immune cells to restore part of their protective function against Alzheimer's disease.

The study, published in the journal Cell Death and Disease, shows that the compound, called OLE, helps microglia enclose and contain beta-amyloid plaques, reducing their size and toxicity. In animal models, the treatment also improved cognitive performance in memory tests.

Alzheimer's disease is characterized, among other factors, by the accumulation of beta-amyloid plaques and by the progressive deterioration of microglia, the immune cells responsible for clearing these toxic deposits from the brain. As the disease progresses, these cells lose part of their protective capacity and contribute to neuronal damage.

In this study, the researchers found that OLE, a molecule derived from the PM20D1 gene, helps restore microglia to a more protective state: the cells move toward the plaques and enclose them, forming a kind of barrier around the deposits that limits their interaction with neurons and reduces their toxic impact on brain tissue.

One of the most significant findings is that we have identified a molecule capable of restoring microglia's protective function. In Alzheimer's disease, these cells become progressively impaired. Our results suggest that this process can be reversed, pointing to new therapeutic and research avenues to counteract the disease."

José Vicente Sánchez Mut, Researcher, Institute for Neurosciences

He also leads the Functional Epi-Genomics of Aging and Alzheimer's Disease laboratory at the IN CSIC-UMH.

Effects of OLE in experimental models

To study the effects of OLE, the team combined different experimental models. First, they used genetically modified worms (C. elegans) engineered to produce beta-amyloid, allowing researchers to assess its toxicity rapidly. In this model, treatment with OLE reduced the accumulation of protein aggregates and improved the worms' mobility, suggesting a protective effect against disease-associated damage.

The team then administered the compound for three months to mouse models of Alzheimer's disease to analyze its effects on the brain and memory. Following treatment, the animals showed improved performance in memory tests and a reduction in the beta-amyloid plaques associated with the disease.

To understand how OLE acts in the brain, the team analyzed the activity of thousands of individual cells. The results showed that microglia were the cell type most affected by the treatment. After administration of the compound, these cells activated mechanisms involved in beta-amyloid clearance and regained their ability to move toward and enclose the plaques.

"Single-cell analysis allowed us to determine that microglia were the cells that responded most strongly to the treatment", says Victoria Pozzi, first author of the study. "From there, we observed that the compound helped these cells move toward beta-amyloid plaques and better contain the damage associated with the disease", adds the researcher.

In addition, the team confirmed in cell cultures that microglia treated with OLE showed an increased ability to move toward beta-amyloid deposits and promote their clearance. Likewise, in neuronal cultures exposed to stress conditions similar to those observed in Alzheimer's disease, the treatment increased cell survival, suggesting that it also exerts a direct protective effect on neurons.

The study's findings are protected by two European patents, one of them owned by the CSIC. According to the authors, this advance reinforces the translational potential of the research and its possible future development in the therapeutic field.