Astrocytic lipid and ketone metabolism linked to improved wound repair after spinal cord injury
Research Analysis
The authors re‑examined single‑cell and spatial transcriptomic datasets and performed targeted experiments in mice to show that reactive astrocytes at the lesion border up‑regulate fatty‑acid oxidation and ketogenesis. This metabolic shift coincides with enhanced astrocyte proliferation, lipid‑droplet accumulation, and neuroprotective effects on injured neurons, suggesting a mechanistic link between astrocytic ketone production and wound healing after spinal cord injury.
Study and findings
Using publicly available single‑nucleus RNA‑seq (snRNA‑seq) and spatial transcriptomics (ST) data from mouse spinal cord injury (SCI), the authors identified a subpopulation of astrocytes (cluster 0) enriched for lipid‑metabolism genes. Gene‑set scoring and GSEA confirmed that fatty‑acid oxidation (FAO) and ketone‑body pathways were up‑regulated, peaking at 14 days post‑injury. Independent scRNA‑seq data reproduced this expansion. In vivo, astrocytes isolated from injured cords displayed abundant lipid droplets (LDs) by BODIPY staining and TEM, increased expression of the LD protein PLIN2, and heightened FAO measured by oxygen‑consumption assays. Metabolic flux with ^13C‑palmitate showed elevated production of β‑hydroxybutyrate (β‑OHB) and up‑regulation of HMGCL and HMGCS2, the key ketogenic enzymes. Conditioned medium from injured astrocytes rescued neurons subjected to oxygen‑glucose deprivation, reducing oxidative stress and improving survival; these benefits were abolished by the ketogenesis inhibitor hymeglusin and mimicked by exogenous β‑OHB. Astrocyte‑specific knockout of CPT1A, the rate‑limiting FAO enzyme, impaired the metabolic shift, reduced LD accumulation, and worsened functional recovery, indicating that CPT1A‑dependent FAO and ketogenesis are required for the observed protective phenotype.
Clinical interpretation
The data indicate that, after SCI, a subset of reactive astrocytes adopts a lipid‑oxidative and ketogenic phenotype that supports neuronal survival and tissue repair. By converting fatty acids into ketone bodies, astrocytes provide an alternative fuel and antioxidant substrate to compromised neurons. The requirement for CPT1A suggests that enhancing astrocytic FAO could be a therapeutic avenue. Although the authors also report that a ketogenic diet (KD) promotes wound repair in this model, the mechanistic evidence points to astrocyte‑intrinsic metabolic reprogramming rather than systemic ketosis per se. Translating these findings to patients would require confirmation that human astrocytes can similarly up‑regulate FAO and ketogenesis after injury and that targeted modulation of this pathway is safe and effective.
Limitations and open questions
The study relies on mouse models and reanalysis of existing transcriptomic datasets; direct evidence in human spinal cord tissue is limited to CSF β‑OHB measurements, which do not pinpoint astrocytic origin. Astrocyte‑specific CPT1A deletion may affect other metabolic functions beyond ketogenesis, complicating causal attribution. The ketogenic diet intervention was not dissected from other dietary components, leaving uncertainty about the relative contribution of systemic versus astrocytic ketosis. Future work should (i) verify astrocytic ketone production in human SCI samples, (ii) test pharmacologic activation of CPT1A or FAO in a clinically relevant setting, and (iii) determine whether the protective effect persists across injury severities and ages.
Source
Pan D et al., Advanced Science, 2026.