Neuronal SORT1 Protein Shields Brain Cells From Alzheimer’s Damage in New Study

A neuronal protein called sortilin-1, or SORT1, may act as a molecular coordinator that keeps Alzheimer’s disease processes in check, according to a study published in Alzheimer’s Research & Therapy. The work, led by Mingjiao Zhang, Xia Yao, Jiaxuan Gu and Xiaoli Rong, shows that when neurons lack SORT1, their internal trafficking systems falter, toxic protein fragments accumulate, and nearby immune cells shift into a damaging inflammatory state. Restoring the protein, by contrast, eased several hallmarks of the disease in cell and animal models.

SORT1 belongs to the VPS10P-domain receptor family, proteins known to shuttle cargo between cellular compartments and to participate in proteostasis, the cell’s system for maintaining a healthy balance of proteins. The receptor had already been implicated in Alzheimer’s genetic risk, but its exact role in neurons remained unclear. The new study positions it as a potential integrator of two processes that increasingly appear intertwined in the disease: endosomal dysfunction inside neurons and chronic neuroinflammation driven by microglia, the brain’s resident immune cells.

To probe that role, the researchers built a co-culture system combining human neurons derived from induced pluripotent stem cells with microglia-like cells. When neuronal SORT1 was deficient, the team observed disrupted endosomal trafficking and a breakdown of proteostatic balance. The consequences were concrete: amyloid precursor protein fragments known as beta-C-terminal fragments, or beta-CTFs, piled up inside the neurons, alongside pathological tau species, both of which are closely tied to Alzheimer’s pathology.

The damage did not stay confined to neurons. In the co-culture dishes, SORT1-deficient neurons were accompanied by heightened pro-inflammatory activation of the microglia-like cells, and the neurons themselves became more vulnerable to injury.

Single-cell RNA sequencing added a temporal dimension to the story. The analyses revealed that SORT1 was dynamically expressed in inflammatory microglial populations, supporting what the authors describe as early adaptive activation but declining in late-stage Alzheimer’s disease, a shift that coincided with chronic neuroinflammation.

The protective side of the equation emerged when the researchers preserved or boosted neuronal SORT1. In their models, maintaining the protein stabilized endosomal organization, dampened maladaptive microglial responses and promoted neuronal survival. This indicates that SORT1 does not merely protect neurons cell-autonomously; it also shapes the immune environment surrounding them, positioning the receptor at a critical junction between neuronal housekeeping and neuroimmune signaling.

Using an adeno-associated virus vector to drive neuronal SORT1 expression, the researchers delivered the protein to neurons and then assessed a battery of disease-relevant outcomes.

The results were striking across multiple measures. Neuronal SORT1 expression reduced DNA damage in the treated animals, decreased microglia-associated neuroinflammation, reduced the burden of amyloid-beta plaques and improved cognitive performance. The convergence of molecular, cellular and behavioral improvements suggests that a single trafficking receptor can influence several disease processes at once, from protein accumulation to immune activation to memory.

The authors conclude that neuronal SORT1 acts as a critical regulator that preserves endosomal homeostasis, coordinates neuron-microglia crosstalk and mitigates neurodegeneration and cognitive decline in Alzheimer’s disease models. They highlight the receptor's potential as a target for early therapeutic intervention, noting that SORT1 expression appears to support early adaptive microglial activation but declines in late-stage Alzheimer's disease, coinciding with chronic neuroinflammation.

As with all preclinical work, important caveats apply. The published version of the article is being shared early as accepted peer-reviewed research and remains subject to further edits before the final version of record.

Subject of Research: The role of the neuronal receptor SORT1 in endosomal homeostasis, neuroinflammation and Alzheimer's disease models

Article Title: Neuronal SORT1 coordinates endosomal homeostasis and neuroinflammation crosstalk to protect against Alzheimer’s disease

Article References: Zhang, M., Yao, X., Gu, J., & Rong, X. (2026). Neuronal SORT1 coordinates endosomal homeostasis and neuroinflammation crosstalk to protect against Alzheimer’s disease. Alzheimer's Research & Therapy. https://doi.org/10.1186/s13195-026-02212-3

Image Credits: AI Generated

DOI: 10.1186/s13195-026-02212-3

Keywords: Alzheimer's disease, SORT1, sortilin, endosomal trafficking, neuroinflammation, microglia, 5xFAD mouse model, APP beta-CTFs, tau, iPSC-derived neurons, single-cell RNA sequencing, gene therapy