Astroglial Kir4.1 ion channel deficit drives chronic migraine – KirMig

Migraine is the most debilitating of all neurological disorders, imposing significant societal costs. The majority of its clinical, financial, and emotional burden stems from chronic migraine. A key driver of migraine chronicity is central sensitization, which involves the heightened activity of neurons and circuits within pain pathways. Specifically, sensitization within the medullary dorsal horn (MDH), the first central relay for trigeminal pain (headache) processing, contributes to pain hypersensitivity. Emerging evidence highlights the crucial role of astrocytes and their mediators in this process. We recently found that the astroglial inward rectifier potassium channel, Kir4.1, is markedly downregulated in the MDH during chronic inflammatory trigeminal pain. This downregulation was both necessary and sufficient to drive pain hypersensitivity by impairing potassium clearance. Given these findings, we now aim to investigate whether similar alterations in Kir4.1 contribute to chronic migraine. The primary objectives are: (i) to expand upon our preliminary findings by studying a validated model of chronic migraine, (ii) to identify novel molecules leading to pain in migraine upon Kir4.1 downregulation, and (iii) to explore the neural circuits through which Kir4.1 downregulation leads to pain hypersensitivity. To address these aims, we will employ a range of cutting-edge techniques, including virally-mediated bidirectional modulation of Kir4.1 expression in astrocytes, systematic transcriptomic analysis and two-photon calcium imaging. These approaches will be complemented by electrophysiological, morphological, biochemical, molecular, pharmacological, and behavioral assays in a validated animal model of chronic migraine. Our results will provide a foundation for understanding astrocyte involvement in chronic migraine and exploring the therapeutic potential of targeting central Kir4.1 channels as a new treatment strategy.