A single transcription factor, NeuroD1, enables the direct conversion of brain-resident immune cells into functional neurons after stroke, restoring lost neurological function. This breakthrough shows promise for regenerating brain tissue, offering a potential future therapy for age-related neurodegeneration and stroke-induced disabilities by replenishing neurons within damaged areas.
October 2023 – PNAS
Key takeaways
- Brain immune cells become neurons: Researchers successfully reprogrammed microglia and macrophages, immune cells that naturally gather at brain injury sites, into fully functional neurons using a single factor called NeuroD1. This direct in vivo conversion bypasses stem cell stages and offers a targeted method for replenishing lost neurons where traditional neurogenesis is limited
- Functional recovery is directly linked: Converted neurons not only survived and matured but also integrated into existing brain circuits, improving motor functions in stroke-affected mice. Ablating these newly formed neurons reversed the recovery, confirming their direct and essential role in restoring neurological function rather than triggering indirect repair pathways
- Potential for age-related brain repair: The adult brain’s natural ability to generate new neurons declines with age, but this technique bypasses that limitation by transforming available immune cells into replacement neurons. It opens the door to therapeutic strategies for age-related cognitive decline, neurodegeneration, and stroke recovery by harnessing the brain’s own immune cells
- High efficiency and long-term stability: Around 70% of reprogrammed cells became striatal projection neurons, crucial for motor control, and maintained their function long-term. These neurons formed correct connections and exhibited normal electrical activity, showing not just transformation but functional integration that persisted, a key requirement for lasting brain repair and rejuvenation
Read the article at: Irie, Takashi, et al. “Direct neuronal conversion of microglia/macrophages reinstates neurological function after stroke.” PNAS, vol. 120, no. 42, 2023, https://doi.org/10.1073/pnas.2307972120.
