Hippo–YAP/TAZ Signaling in Astrocytes and Microglia: Role in Neuroinflammation, Neurodegeneration and Glial Tumors

Glial cells, particularly astrocytes and microglia, are central to maintaining CNS homeostasis and coordinating responses to injury through tightly regulated metabolic, inflammatory, and mechanosensitive processes. Emerging evidence identifies the Hippo signaling pathway and its downstream effectors YAP/TAZ as key regulators of glial functions, influencing proliferation, polarization, intercellular communication, and the balance between neuroprotection and neurotoxicity. This review discusses the Hippo signaling pathway and its transcriptional co-activators YAP/TAZ as context-dependent hubs integrating mechanical, metabolic, and immune cues in astrocytes and microglia. Particular attention is given to MST1/2- and YAP/TAZ-dependent signaling in microglia, which governs inflammatory states, redox balance, mitophagy, and mechanosensing. In astrocytes, Hippo-YAP signaling emerges as a bidirectional regulator of reactive gliosis and neuroprotection, capable of constraining excessive scar formation. However, when chronically suppressed, it impairs glutamate clearance, metabolic support, and resistance to neurodegeneration. Disruption of Hippo signaling in glial tumors is also considered, with YAP/TAZ-TEAD complexes driving glioblastoma stemness, infiltrative growth, immune evasion, and therapy resistance. Finally, therapeutic perspectives are outlined that emphasize context-selective modulation of Hippo signaling in the CNS. Overall, Hippo-YAP/TAZ signaling is presented as a highly context-dependent regulator at the interface of glial inflammation, neurodegeneration, and glioma biology and as a promising but demanding target for future CNS therapies.