THE ROLE OF GIRK CHANNELS IN BERGMANN GLIA CELLS

Kir3.1 (GIRK1), a G protein-coupled inwardly rectifying potassium channel, plays a critical role in regulating neuronal excitability by hyperpolarizing the membrane potential and reducing neuronal firing. It is predominantly expressed in neurons throughout the central nervous system. Findings from our laboratory suggest that GIRKs, traditionally characterized as neuronal channels, interact with inwardly rectifying (Kir) channels from other subfamilies, such as Kir4.1, which is expressed in glia cells. This unexpected interaction was examined in a heterologous expression system, revealing that GIRK1 exerts a dominant-negative effect on native Kir4.1 currents.
Notably, recent studies have reported high transcript levels of GIRK1 in cerebellar Bergmann glia. These cells are known to regulate cerebellar homeostasis, guide neuronal migration, and contribute to motor and cognitive processes. The emerging evidence points to previously unrecognized roles for GIRK1 in Bergmann glia, potentially reshaping our understanding of their contribution to cerebellar circuitry.
To explore this further, we generated an inducible, cell type–specific knockout mouse line enabling selective deletion of GIRK1 from Bergmann glia. Behavioral analyses revealed a sex-specific phenotype, with altered social behavior and enhanced motor learning observed only in females. Single-cell RNA sequencing further suggested a non–cell-autonomous mechanism, whereby granule cells—closely associated with Bergmann glia—respond to the knockout by upregulating genes related to endoplasmic reticulum stress.
This study aims to elucidate the biological significance of GIRK1 in astrocytes and to define its role in shaping Bergmann glia function, thereby providing new insight into the broader physiological roles of GIRK channels in glial cells.