ASTROCYTIC MITOTYPES: MAPPING REGION-SPECIFIC MITOCHONDRIAL FUNCTION IN HEALTH AND ALZHEIMER’S DISEASE

Astrocytic mitochondria play a key role in shaping region-specific brain activity, yet their contributions remain poorly understood. Mitochondria, essential for brain homeostasis, exhibit distinct phenotypes known as mitotypes across cell types and regions, reflecting specialized metabolic and functional profiles. To investigate astrocyte-specific mitochondrial function, we implemented immunocapture of CPT1A (carnitine palmitoyltransferase 1A)–a protein enriched in astrocytic mitochondria– in wild-type and Alzheimer’s disease (AD) mouse models.
We first confirmed the enrichment of CPT1A in astrocytes relative to non-astrocytic cells using Western blot analysis and immunohistochemistry. We then established a method to immunocapture intact CPT1A-positive mitochondria from mitochondrial fractions isolated from adult mouse brain. Functional validation using Seahorse assays demonstrated robust mitochondrial respiration in CPT1A-positive mitochondria, whereas IgG control samples, which lacked mitochondria, showed no response. Western blot analysis further confirmed enrichment of CPT1A-positive mitochondria in the immunocaptured fraction compared to controls.
Using this approach, we are assessing the bioenergetic, proteomic, and lipidomic signature of region-specific astrocytic mitochondria isolated from the cortex, hippocampus, and cerebellum of wild-type mice. We will then compare hippocampal astrocytic mitochondrial profiles between wild-type and 5XFAD mouse model of AD.
Together, these studies will provide critical insight into the functional properties of astrocyte-derived mitochondria and establish a foundation for future mechanistic investigations into the interplay between mitochondrial biology, brain cell type, and brain region. Ultimately, this work may open new therapeutic avenues in precision medicine by targeting astrocytic mitochondria in neurodegenerative diseases such as AD.