Restoration of Cingulate Long-Term Depression by Enhancing Non-apoptotic Caspase 3 Alleviates Peripheral Pain Hypersensitivity

Nerve injury in somatosensory pathways may lead to neuropathic pain, which affects the life quality of ∼8% of people. Long-term enhancement of excitatory synaptic transmission along somatosensory pathways contributes to neuropathic pain. Caspase 3 (Casp3) plays a non-apoptotic role in the hippocampus and regulates internalization of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunits. Whether Casp3-AMPAR interaction is involved in the maintenance of peripheral hypersensitivity after nerve injury remained unknown. Here, we show that nerve injury suppresses long-term depression (LTD) and downregulates Casp3 in the anterior cingulate cortex (ACC). Interfering with interactions between Casp3 and AMPAR subunits or reducing Casp3 activity in the ACC suppresses LTD induction and causes peripheral hypersensitivity. Overexpression of Casp3 restores LTD and reduces peripheral hypersensitivity after nerve injury. We reveal how Casp3 is involved in the maintenance of peripheral hypersensitivity. Our findings suggest that restoration of LTD via Casp3 provides a therapeutic strategy for neuropathic pain management.