Deficiency of purinergic receptor P2X7 attenuates neointima hyperplasia in mice after carotid artery wire injury

Vascular restenosis remains a major clinical challenge following interventional treatments for cardiovascular diseases. While P2X7-mediated inflammatory responses have been implicated in various cardiovascular conditions, its role in post-injury neointimal hyperplasia through macrophage-VSMC paracrine crosstalk remains incompletely understood. A carotid artery wire injury model was established to induce neointimal hyperplasia in mice. P2X7 protein expression was examined by Western blotting and immunofluorescence staining. Mice with carotid artery wire injury were treated with a P2X7 receptor antagonist or PBS vehicle control. Additionally, P2X7 knockout mice were used to investigate the role of P2X7 deficiency in intimal hyperplasia, cytokine expression, and smooth muscle cell behavioral responses. Furthermore, VSMCs were cultured with conditioned media derived from ATP-stimulated wild-type or P2X7-deficient macrophages to evaluate proliferative and migratory responses. P2X7 was significantly upregulated in carotid arteries with neointimal hyperplasia and showed predominant co-localization with macrophages. Pharmacological antagonism or global genetic deletion of P2X7 significantly attenuated intimal hyperplasia, reduced cellular proliferation, increased α-SMA immunoreactivity, and decreased caspase-1 activation. P2X7 knockout also reduced IL-1β and IL-18 immunoreactivity in vascular tissue, consistent with attenuated intimal inflammation. Compared with conditioned media from ATP-activated P2X7-deficient macrophages, conditioned media from ATP-activated wild-type macrophages significantly promoted VSMC proliferation and migration, supporting a model in which macrophage-associated P2X7 signaling contributes to a paracrine milieu that promotes VSMC proliferation and migration. These findings support an association between P2X7-dependent macrophage inflammatory signaling and VSMC proliferative and migratory responses during neointimal hyperplasia. P2X7 may therefore represent a candidate target for further investigation in vascular restenosis.