Microglia play a central role in the neuroinflammation associated with Alzheimer’s disease (AD). At the 20th International Conference on Alzheimer’s and Parkinson’s Diseases (AD/PD), scientists focused on TREM2, a microglial receptor that regulates immune responses, exploring new ways to address neuroinflammation. 

Microglia play a central role in the neuroinflammation associated with Alzheimer’s disease (AD). These cells act as the brain’s immune system and respond to damage signals such as amyloid accumulation. When the process starts, the initial microglial response can be protective. However, in later stages, this response becomes dysfunctional and contributes to disease progression. At the 20th International Conference on Alzheimer’s and Parkinson’s Diseases (AD/PD), scientists focused on TREM2, a microglial receptor that regulates immune responses, exploring new ways to address neuroinflammation. 

In Alzheimer’s disease, microglia act as a double-edged sword. They can either protect the brain or worsen the damage, depending on their activation state. Inflammatory activation harms healthy neurons. However, a study reveals that a special type of microglia expressing specific receptors and behaving like T cells may help mitigate this neurodegenerative condition.

“Loss of synapses and dysfunctional synapses in a region-specific way is important in Alzheimer’s. It’s actually the strongest correlate of cognitive decline, far more so than plaques and tangles, which are the pathological hallmarks,” Soyon Hong told the audience at the XVII Meeting on Glial Cells in Health and Disease, which was held in Marseille last week.

Melanoma is the most aggressive form of skin cancer and often spreads to the brain. Though immunotherapy has greatly improved the outlook for even metastatic melanoma patients, once melanoma brain metastases (MBM) develop, prognosis worsens, and available therapeutic options decline. Scientists at the Institute for Neurosciences (IN), a joint center of the Spanish National Research Council (CSIC) and the Miguel Hernández University of Elche (UMH) have found a way to tackle MBM through microglial reprogramming.

The way the brain ages is not the same in women and men. A study in mice has observed differences in the expression of the maternal and paternal X chromosomes that could explain variation in brain aging between the sexes and a faster deterioration in some women. Another study has discovered different survival strategies in the microglial cells of females and males. Both studies highlight sex differences that could have implications for several age-related neurological disorders, such as Alzheimer’s or Parkinson’s.

Reducing microglial activity in the presence of apolipoprotein E4 (APOE4) has uncovered a mechanism associated with the deposition of misfolded amyloid and tau in a novel mouse model of Alzheimer’s disease. By transplanting human neurons into the mouse brain and eliminating the mouse microglia, scientists at the Gladstone Institutes in San Francisco observed that amyloid and tau deposition was reduced. These results support therapeutic strategies that target APOE4 and microglia.

Using microglia and an unbiased screening method, investigators have identified almost 60 previously unknown targets for γ-secretase. Investigators from KU Leuven and colleagues published their results in Molecular Cell on Nov. 16, 2023.