Simple and highly specific targeting of resident microglia with adeno-associated virus

Microglia, as the immune cells of the central nervous system (CNS), play dynamic roles in both healthy and diseased conditions. The ability to genetically target microglia using viruses is crucial for understanding their functions and advancing microglia-based treatments. We here show that resident microglia can be simply and specifically targeted using adeno-associated virus (AAV) vectors containing a 466-bp DNA fragment from the human <i>IBA1</i> (<i>hIBA1</i>) promoter. This targeting approach is applicable to both resting and reactive microglia. When combining the short <i>hIBA1</i> promoter with the target sequence of <i>miR124</i>, up to 98% of transduced cells are identified as microglia. Such a simple and highly specific microglia-targeting strategy may be further optimized for research and therapeutics.