ABSTRACT
OBJECTIVE To identify the role of mixed lineage kinase domain like protein(MLKL)in cerebral small vessel disease(CSVD)and explore the underlying mechanism.METHODS Transient bilateral common carotid artery occlusion(tBCCAO)was used to establish a mouse model of CSVD.Immunofluorescence staining and Western blotting were used to observe the expres-sions of RIPK3/MLKL signaling molecules in brain tissues at 7,14 and 28 d after tBCCAO.Open field test,rotarod test,Y-maze and novel object recognition test were used to observe the effect of MLKL knockout on cognitive func-tion after tBCCAO.Blood-brain barrier(BBB)disruption was observed by sodium fluorescein permeability test and the expressions of tight junction proteins.Immunoflu-orescence staining and Western blotting were used to detect the expression of microglia marker Iba-1,astro-cyte marker GFAP,and NLRP3/Caspase-1 signaling mol-ecules in the hippocampus of CSVD mice.ELISA was used to detect the level of inflammatory factors(TNF-α,IL-1β,IL-18)in hippocampus.RESULTS The expres-sions of RIPK3/MLKL signaling molecules increased in cortex and hippocampus after tBCCAO,especially on day 14.The expression of pMLKL mainly increased in neurons,glia cells and endothelial cells in CSVD mice.MLKL knockout improved the cognitive functions such as motor learning,spatial learning and working memory,and object recognition ability in CSVD mice.MLKL knock-out alleviated the leakage of sodium fluorescein and attenuated the down-regulation of tight junction proteins at 1 d and 14 d after tBCCAO.At 14 d after tBCCAO,MLKL knock out inhibited the activations of microglia and astrocytes,attenuated the expressions of NLRP3/cas-pase-1 molecules,and decreased the levels of inflamma-tory factors in the hippocampus of mice.CONCLUSION Genetic inhibition of MLKL exerts protective effects against cognitive impairment by ameliorating BBB dam-age and neuroinflammation in a mouse cerebral small vessel disease model.