[2PL-2_2] 【Relay】Microglia in the choreography of brain construction

[2PL-2_2] Microglia in the choreography of brain construction

*Sonia GAREL^1,2 (1. College de France, CIRB, Paris, France, 2. Ecole Normale Superieure, IBENS, Paris, France)

Keywords:

Microglia,Brain development,Tissue integrity,neuroglial interactions

Microglia, the main resident immune cells of the brain, are highly dynamic and responsive to their environment. Their capacity for cellular and transcriptomic change is especially evident during development, but also features prominently in ageing and neurodegenerative diseases. Understanding microglial biology therefore requires examining not only their roles in pathology, but also the contexts in which their functional programs first emerge and are progressively refined. In this lecture, we will explore how early brain development provides a unique lens to understand foundational aspects of microglial function and adaptation.As they colonize the embryonic brain—arriving before most other glial populations—microglia are positioned at the center of brain construction, when tissue architecture is being established and actively remodeled. We will present published and unpublished work showing how microglia contribute to building and maintaining the developing brain, safeguarding tissue integrity during periods of intense morphogenetic change while shaping the structural and molecular environment of the emerging tissue. We will further discuss how some of these early functional states resemble those observed in neurodegenerative conditions, suggesting that developmental programs may be redeployed, sustained, or dysregulated later in life. Development thus provides a privileged window to reveal core features of microglial biology that shape brain function and vulnerability across the lifespan, in health and disease.