A new weapon against Alzheimer’s: enhanced microglia (magenta) clearing toxic amyloid plaques (blue). A promising preclinical study from Cedars-Sinai. Credit: Cedars-Sinai
A potential new strategy against Alzheimer’s disease is taking shape in the brain’s own defense system. By boosting a specific enzyme in the brain’s immune cells, researchers at Cedars-Sinai have dramatically reduced the hallmark plaques of Alzheimer’s and reversed cognitive decline in mice. The news opens the door to potential cellular therapies for a disease that affects more than 7 million Americans and has a $781 billion associated economic drag on the U.S. economy.
The brain’s dedicated immune cells, microglia, patrol the neural environment like housekeepers, clearing away waste and debris to maintain healthy conditions for neurons. But in Alzheimer’s disease, these cells appear to become exhausted. Their fatigue allows toxic amyloid-beta proteins to accumulate into the sticky plaques that characterize the disease, ultimately damaging neurons and impairing cognition.
Dr. Warren Tourtellotte and his team at Cedars-Sinai hypothesized that enhancing a particular enzyme within microglia could rejuvenate them. The enzyme in question? Angiotensin-Converting Enzyme (ACE), which is better known for regulating blood pressure, but increasingly recognized for its role in the brain’s immune response.
Supercharging the brain’s defense
To test their theory, the investigators turned to genetic engineering. They developed laboratory mice that accumulated amyloid plaques in their brains, then modified them to overexpress ACE specifically in their microglia.
The results were clear. “We found that by using gene editing to boost ACE in immune cells called microglia, which we believe become exhausted in the brains of patients with Alzheimer’s disease, we supercharged those cells and seemed to restore them to full function,” said Tourtellotte in a press release. Tourtellotte serves as professor of Pathology and Laboratory Medicine, Neurology, Neurosurgery, and Biomedical Sciences at Cedars-Sinai. This restoration allowed the microglia to clear amyloid plaques and reverse both neurodegeneration and cognitive decline.
The mice with enhanced microglial ACE showed significant reductions in amyloid plaques throughout key brain regions. Damage to neurons was lessened. Vital connections between brain cells appeared to be rescued. Most importantly, the mice performed significantly better on learning and memory tests. which remains the gold standard for measuring cognitive function in Alzheimer’s research.
Part of a broader push
This novel approach aligns with a growing recognition of microglia’s multifaceted role in Alzheimer’s disease. While these cells can protect the brain by clearing harmful proteins, they can also contribute to neuroinflammation that worsens the condition. Finding ways to enhance their beneficial activities while dampening their harmful ones has become a key research priority.
The Cedars-Sinai study also fits into the burgeoning field of gene and cellular therapies for neurodegenerative diseases. The success of gene-editing technologies like CRISPR in other areas of medicine has inspired hope for treating Alzheimer’s. Some clinical trials are already testing gene therapies that introduce protective versions of genes like apolipoprotein E (APOE). Others are exploring “gene silencing” drugs that reduce production of harmful tau protein, another key player in Alzheimer’s pathology.
From mice to medicine
The crucial next step is confirming that the same ACE-related biology exists in human microglia. If these findings translate, they could pave the way for a novel cell-based therapy.
Such a treatment might work like this: harvest a patient’s own immune cells, genetically modify them to boost ACE expression, then reintroduce them to the brain to fight the disease. This approach could potentially work alone or complement other Alzheimer’s therapies currently in development.
“Scientific discovery is the key to developing treatments that will help us overcome Alzheimer’s disease,” said Dr. Nancy L. Sicotte, chair of the Department of Neurology at Cedars-Sinai. These findings, from the first pilot project funded by the Jona Goldrich Center for Alzheimer’s and Memory Disorders at Cedars-Sinai, point toward a promising new direction.
While this research remains in preclinical stages, it promises something valuable: a fresh approach in the ongoing quest to find effective treatments. By focusing on empowering the brain’s own defense mechanisms rather than simply clearing plaques from the outside, this work provides a hopeful glimpse into the future of Alzheimer’s therapy.
The study was published in Nature Aging with support from NIH grants and the Cedars-Sinai Goldrich Alzheimer’s Center. Additional authors include Andrew R. Gomez, Hyae Ran Byun, Shaogen Wu, A. K. M. Ghulam Muhammad, Jasmine Ikbariyeh, Jaelin Chen, Alek Muro, Lin Li, Kenneth E. Bernstein, and Richard Ainsworth.
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