Targeting the KCNC3-Dependent Anterior Insular-Lateral Orbitofrontal Cortex Glutamatergic Circuit Attenuates...

Traumatic brain injury (TBI) is a prevalent cause of secondary neuropsychiatric disorders, with post-traumatic anxiety significantly worsening long-term outcomes. However, the key neural circuits and molecular mechanisms underlying post-TBI anxiety remain poorly understood. Here, we show that TBI patients with frontal lobe injuries and anxiety exhibited increased activity and enhanced functional connectivity in the anterior insular cortex (aIC) and lateral orbitofrontal cortex (lOFC). Mechanistically, we established a mouse model of moderate frontal lobe TBI, categorizing animals into anxious and non-anxious TBI groups. BOLD-fMRI and c-Fos expression analyses revealed that mice with post-traumatic anxiety also exhibited increased activity in the aIC and lOFC, as well as heightened activity in the aIC-lOFC glutamatergic circuit. Optogenetic and chemogenetic modulation of this circuit bidirectionally regulated post-traumatic anxiety. Single-cell RNA sequencing of aIC glutamatergic neurons identified a specific downregulation of KCNC3 in anxious TBI mice. Functional validation confirmed that KCNC3 downregulation mediates hyperactivity in the aIC-lOFC glutamatergic circuit and induces post-traumatic anxiety. Together, these findings unveil a critical role of TBI‑induced KCNC3 downregulation in aIC glutamatergic neurons in driving hyperactivity of the aIC-lOFC glutamatergic circuit and resulting post‑traumatic anxiety, and they suggest KCNC3 and the aIC-lOFC circuit as promising therapeutic targets for post‑TBI anxiety.