Activation of sarco/endoplasmic reticulum Ca²⁺-ATPase 2 (SERCA2) reduces brain injury and improves cognitive function following ischemic stroke.

Ischemic stroke is a leading cause of death and long-term disability worldwide, driven in part by disrupted intracellular calcium (Ca²⁺) homeostasis, endoplasmic reticulum stress, oxidative damage, and neuroinflammation. The sarco/endoplasmic reticulum Ca²⁺-ATPase 2 (SERCA2) pump is essential for maintaining intracellular Ca²⁺ balance, and its dysfunction contributes to ischemic neuronal injury. Here, we investigated the neuroprotective effects of CDN1163, a small-molecule allosteric activator of SERCA2, in a murine model of photothrombotic stroke (pt-MCAO). Male C57BL/6 J mice received CDN1163 (50 mg/kg, i.p.) at 1, 24, 48, and 72 h after stroke induction. Neurological and cognitive outcomes were assessed using CatWalk gait analysis, novel object recognition (NOR), and the Morris water maze. Infarct volume, blood-brain barrier integrity, oxidative stress, apoptosis, NLRP3 inflammasome activation, intracellular Ca²⁺ dynamics, and SERCA ATPase activity were evaluated by TTC staining, immunoblotting, TUNEL assay, intracellular calciumimaging, and ATPase assay, respectively. CDN1163 significantly reduced infarct volume, brain oedema, and IgG extravasation, while restoring SERCA2 expression and preserving blood-brain barrier integrity. CDN1163 treatment also improved intracellular Ca²⁺ handling and enhanced SERCA2 ATPase activity following pt-MCAO stroke. Mechanistically, CDN1163 suppressed NLRP3 inflammasome signaling, reduced oxidative stress markers (4-HNE and nitrotyrosine) and apoptotic markers (Bax and cleaved PARP-1), decreased TUNEL-positive cells, and increased oxidative phosphorylation protein expression. These molecular changes were accompanied by improved gait performance and cognitive recovery. Collectively, these findings identify pharmacological activation of SERCA2 by CDN1163 as a promising therapeutic strategy for ischemic stroke by restoring Ca²⁺ homeostasis and attenuating neuroinflammatory and oxidative injury.