NLRP3 inflammasome inhibition with MCC950 improves diabetes-mediated cognitive impairment and vasoneuronal remodeling after ischemia.

Diabetes increases the risk and worsens the progression of cognitive impairment via the greater occurrence of small vessel disease and stroke. Yet, the underlying mechanisms are not fully understood. It is now accepted that cardiovascular health is critical for brain health and any neurorestorative approaches to prevent/delay cognitive deficits should target the conceptual neurovascular unit (NVU) rather than neurons alone. We have recently shown that there is augmented hippocampal NVU remodeling after a remote ischemic injury in diabetes. NLRP3 inflammasome signaling has been implicated in the development of diabetes and neurodegenerative diseases, but little is known about the impact of NLRP3 activation on functional and structural interaction within the NVU of hippocampus, a critical part of the brain that is involved in forming, organizing, and storing memories. Endothelial cells are at the center of the NVU and produce trophic factors such as brain derived neurotrophic factor (BDNF) contributing to neuronal survival, known as vasotrophic coupling. Therefore, the aims of this study focused on two hypotheses: 1) diabetes negatively impacts hippocampal NVU remodeling and worsens cognitive outcome after stroke, and 2) NLRP3 inhibition with MCC950 will improve NVU remodeling and cognitive outcome following stroke via vasotrophic (un)coupling between endothelial cells and hippocampal neurons. Stroke was induced through a 90-min transient middle cerebral artery occlusion (MCAO) in control and high-fat diet/streptozotocin-induced (HFD/STZ) diabetic male Wistar rats. Saline or MCC950 (3 mg/kg), an inhibitor of NLRP3, was injected at 1 and 3 h after reperfusion. Cognition was assessed over time and neuronal density, blood-brain barrier (BBB) permeability as well as NVU remodeling (aquaporin-4 [AQP4] polarity) was measured on day 14 after stroke. BDNF was measured in endothelial and hippocampal neuronal cultures under hypoxic and diabetes-mimicking condition with and without NLRP3 inhibition. Diabetes increased neuronal degeneration and BBB permeability, disrupted AQP4 polarity, impaired cognitive function and amplified NLRP3 activation after ischemia. Inhibition with MCC950 improved cognitive function and vascular integrity after stroke in diabetic animals and prevented hypoxia-mediated decrease in BDNF secretion. These results are the first to provide essential data showing MCC950 has the potential to become a therapeutic to prevent neurovascular remodeling and worsened cognitive decline in diabetic patients following stroke.

Ward R ，Li W ，Abdul Y ，Jackson L ，Dong G ，Jamil S ，Filosa J ，Fagan SC ，Ergul A ... -  《-》

Inhibition of the NLRP3 inflammasome reduces brain edema and regulates the distribution of aquaporin-4 after cerebral ischaemia-reperfusion.

Brain edema is a common threat to life in ischaemic brain injury. The NLRP3 inflammasome promotes the inflammatory injury after ischaemic stroke. Previous studies have shown that aquaporin-4 (AQP4) modulates brain water transport and endothelin-1 (ET-1) induces cerebral edema. However, the contribution of the NLRP3 inflammasome to regulation of brain edema and blood-brain barrier (BBB) disruption in cerebral ischaemia-reperfusion is elusive. The aim of this study is to investigate the effect of inhibition of the NLRP3 inflammasome by MCC950 on regulation of cerebral edema, BBB disruption and the expression of AQP4 and ET-1 in cerebral ischaemia-reperfusion. The male C57BL/6 mice were used to establish the experimental transient middle cerebral artery occlusion (tMCAO) model. The mice were intraperitoneally injected with MCC950. Changes in NLRP3, IL-1β, IL-18, the pyroptosis protein gasdermin D (GSDMD), brain water content, AQP4 and ET-1 in brain tissue were detected. MCC950 inhibited NLRP3 and GSDMD after tMCAO. MCC950 improved cerebral edema and alleviated the damage of BBB after tMCAO. The levels of AQP4 and ET-1 were decreased by MCC950. In addition, MCC950 regulated the distribution of AQP4 after tMCAO in mice. The NLRP3 inflammasome facilitated brain edema and BBB disruption after cerebral ischaemia-reperfusion in mice, and NLRP3 inflammasome inhibition with MCC950 regulated the expression and distribution of AQP4 in the infarct area. Hence, the NLRP3 inflammasome is considered to be an important target for the treatment of brain edema in cerebral ischaemia-reperfusion, and MCC950 has potential value for ischaemic stroke treatment.

Wang H ，Chen H ，Jin J ，Liu Q ，Zhong D ，Li G ... -  《-》

Inhibition of NLRP3 inflammasome alleviates cognitive deficits in a mouse model of anti-NMDAR encephalitis induced by active immunization.

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a neurological disorder, characterized by cognitive deficits as one of its vital features. The nucleotide-binding oligomerization domain-like receptor (NLRP3) inflammasome is a key contributor to neuroinflammation and cognitive deficits in neurological diseases. However, the underlying mechanism of anti-NMDAR encephalitis remains unclear, and the biological function of the NLRP3 inflammasome in this condition has not been elucidated. In this study, a mouse model of anti-NMDAR encephalitis was induced by active immunization with the GluN1356-385 peptide (NEA model). The NLRP3 inflammasome in the hippocampus and temporal cortex was investigated using real-time quantitative PCR (RT-qPCR), western blotting, and immunofluorescence staining. The impact of MCC950 on cognitive function and NLRP3 inflammation was assessed. Confocal immunofluorescence staining and Sholl analysis were employed to examine the function and morphology of microglia. In the current study, we discovered overactivation of the NLRP3 inflammasome and an enhanced inflammatory response in the NEA model, particularly in the hippocampus and temporal cortex. Furthermore, significant cognitive dysfunction was observed in the NEA model. While, MCC950, a selective inhibitor of the NLRP3 inflammasome, sharply attenuated the inflammatory response in mice, leading to mitigated cognitive deficits of mice and more regular arrangements of neurons and reduced number of hyperchromatic cells were also observed in the hippocampus area. In addition, we found that the excess elevation of NLRP3 inflammasome was mainly expressed in microglia accompanied with the overactivation of microglia, while MCC950 treatment significantly inhibited the increased number and activated morphological changes of microglia in the NEA model. Altogether, our study reveals the vital role of overactivated NLRP3 signaling pathway in aggravating the inflammatory response and cognitive deficits and the potential protective effect of MCC950 in anti-NMDAR encephalitis. Thus, MCC950 represents a promising strategy for anti-inflammation in anti-NMDAR encephalitis and our study lays a theoretical foundation for it to become a clinically targeted drug.

Yang X ，Sun A ，Kong L ，Yang X ，Zhao X ，Wang S ... -  《-》

Inhibition of NLRP3 Inflammasome Ameliorates Cerebral Ischemia-Reperfusion Injury in Diabetic Mice.

Hong P ，Li FX ，Gu RN ，Fang YY ，Lai LY ，Wang YW ，Tao T ，Xu SY ，You ZJ ，Zhang HF ... -  《-》

Inhibition of the NLRP3-inflammasome as a potential approach for neuroprotection after stroke.

Ismael S ，Zhao L ，Nasoohi S ，Ishrat T ... -  《Scientific Reports》