Researchers Identify Fibronectin Protein as a Key Factor in Blood-Brain Barrier Damage in Alzheimer's Disease

Uncovering the Underlying Mechanism

According to НВ — Техно: On September 19, scientists revealed that an excess of the protein fibronectin can compromise the blood-brain barrier (BBB) in Alzheimer's disease. Published in the journal Nature Aging, this breakthrough links the barrier's deterioration to a genetic variant known as APOE4, the strongest genetic risk factor for late-onset Alzheimer's.

The blood-brain barrier plays a vital role by allowing oxygen and nutrients to reach the brain while blocking harmful substances like toxins and microbes. Researchers discovered that inflammation and beta-amyloid plaques activate brain cells called astrocytes, triggering an overproduction of fibronectin. This protein accumulates around cerebral blood vessels, disrupting the signals that maintain vessel integrity. As a result, the barrier becomes more permeable, leading to increased vascular leakage and heightened brain inflammation.

Study Details and Findings

The investigation involved analysis of postmortem brain tissue and cerebrospinal fluid from Alzheimer's patients, alongside experiments using human cells, 3D vascular models, APOE4-carrying mice, and zebrafish (Danio rerio). Findings demonstrated that reducing fibronectin levels decreased blood vessel permeability in zebrafish exposed to beta-amyloid. Additionally, blocking fibronectin signaling effectively restored protective communication between vascular cells.

• The FN1 gene is responsible for producing fibronectin.
• A rare loss-of-function variant of this gene in APOE4 carriers lowered Alzheimer's risk by 71%.

Although these results are promising, the research remains preclinical and does not yet prove improvements in memory or cognitive function through barrier restoration. Further animal studies are necessary to assess the safety and efficacy of this approach before progressing to human clinical trials.

While fibronectin contributes negatively to Alzheimer's pathology, it is also essential for tissue repair and normal vascular function. Therefore, future treatments should aim to selectively reduce harmful fibronectin accumulation without disrupting its beneficial roles.

This discovery marks a significant advance in understanding Alzheimer's disease mechanisms and opens new avenues for developing therapeutic strategies. Continued research will be crucial to validate these findings and explore how this knowledge can lead to effective treatments against neurodegenerative disorders.

The interplay between peripheral immune cells and brain inflammation is crucial in understanding Alzheimer’s disease. Recent studies have highlighted how these immune responses can exacerbate damage within the brain, further complicating the pathology of the condition. To explore this connection in detail, read more about how immune cells outside the brain initiate inflammation and contribute to the disease's progression.