SPP1 and Osteopenia: For pericytes, the Spp1 signaling axis (which encodes osteopenia, a molecule that limits inflammation and promotes axon regeneration) and the Tgfb1 signaling axis were markedly enhanced in the PLX group, indicating that replenished microglia can promote the proliferation of pericytes, thereby increasing their coverage and contributing to BBB stabilization (Figure S6D).