A Bioinspired Manganese‐Organic Framework Ameliorates Ischemic Stroke through its Intrinsic Nanozyme Activity and Upregulating Endogenous Antioxidant Enzymes

Abstract

Following stroke, oxidative stress induced by reactive oxygen species (ROS) aggravates neuronal damage and enlarges ischemic penumbra, which is devastating to stroke patients. Nanozyme‐based antioxidants are emerging to treat stroke through scavenging excessive ROS. However, most of nanozymes cannot efficiently scavenge ROS in neuronal cytosol and mitochondria, due to low‐uptake abilities of neurons and barriers of organelle membranes, significantly limiting nanozymes’ neuroprotective effects. To overcome this limitation, a manganese‐organic framework modified with polydopamine (pDA‐MNOF), capable of not only mimicking catalytic activities of natural SOD2's catalytic domain but also upregulating two endogenous antioxidant enzymes in neurons is fabricated. With such a dual anti‐ROS effect, this nanozyme robustly decreases cellular ROS and effectively protects them from ROS‐induced injury. STAT‐3 signaling is found to play a vital role in pDA‐MNOF activating the two antioxidant enzymes, HO1 and SOD2. In vivo pDA‐MNOF treatment significantly improves the survival of middle cerebral artery occlusion (MCAo) mice by reducing infarct volume and more importantly, promotes animal behavioral recovery. Further, pDA‐MNOF activates vascular endothelial growth factor expression, a downstream target of STAT3 signaling, thus enhancing angiogenesis. Taken together, the biochemical, cell‐biological, and animal‐level behavioral data demonstrate the potentiality of pDA‐MNOF as a dual ROS‐scavenging agent for stroke treatment.

Abstract

By mimicking the catalytic domains of natural antioxidant enzymes, a de novo metal‐organic framework modified with polydopamine is fabricated. It not only possesses superoxide dismutase‐like nanozyme activities but also biologically upregulates two endogenous antioxidant enzymes (HO1 and SOD2) through STAT3 signaling, effectively scavenging excessive reactive oxygen species and thereby powerfully salvaging neurons from ischemic insult poststroke.