Sugar first, mitochondria later: how brain immune cells respond to injury
When the brain is injured, its immune cells don’t wait around. New research reveals that microglia, the brain’s resident immune cells, launch their first response using sugar-based energy, long before mitochondria enter the scene.
Using advanced live imaging, scientists observed that microglia rush toward damage and begin their work almost immediately even though their long cellular extensions contain few or no mitochondria at this early stage. Instead, these cells rely on glycolysis, a fast way to generate energy from sugar, allowing them to move quickly and react within minutes.
Only later do mitochondria arrive. Hours after the initial response, microglia reorganize their internal architecture, building microscopic transport routes that allow mitochondria to travel to the most active zones. Once there, mitochondria support sustained functions such as debris clearance and longer-term immune activity.
This two-step strategy challenges the traditional view of mitochondria as constant power suppliers. Instead, it shows that brain immune cells are metabolically flexible, choosing speed first and endurance second.
Why this matters: microglia play a central role in aging, neuroinflammation, and neurodegenerative diseases. Understanding how healthy microglia manage energy over time helps researchers identify what may go wrong in chronic brain disorders and how mitochondrial function might be restored or optimized.
In short, the brain’s immune response is not only fast it is smart, adaptive, and precisely timed.
The World Mitochondria Society will organize 2 meetings dedicated to mitochondria dynamics next April & October.
Sources & More Information
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Pietramale AN et al.
Mitochondria are absent from microglial processes performing surveillance, chemotaxis, and phagocytic engulfment.
Nature Communications, 2025.
DOI: 10.1038/s41467-025-66708-6 -
Espinoza K et al.
Dynamic changes in mitochondria support phenotypic flexibility of microglia.
Nature Communications, 2025.
DOI: 10.1038/s41467-025-66709-5 -
MedicalXpress / Dartmouth College (Video and more information)
Brain immune cells arrive powered by sugar, then build roads to recruit reinforcements.
January 26, 2026.
We are pleased to announce that the 17th Conference Targeting Mitochondria 2026 will be held in Berlin, Germany, from October 21-23. We look forward to welcoming you.
