title: Long Noncoding RNA Malat1 Regulates Cerebrovascular Pathologies in Ischemic Stroke.
abstract: The study was designed to determine the role of long noncoding RNA (lncRNA), metastasis-associated lung adenocarcinoma transcript 1 (Malat1), in ischemic stroke outcome. Primary mouse brain microvascular endothelial cells (BMECs) were cultured and treated with Malat1 GapmeR before 16 h oxygen and glucose depravation (OGD). Cell death was assayed by LDH and MTT methods. Malat1 knock-out and wild-type mice were subjected to 1 h of middle cerebral artery occlusion (MCAO) and 24-72 h of reperfusion. To explore the underlying mechanism, apoptotic and inflammatory factors were measured by qPCR, ELISA, and Western blotting. The physical interaction between Malat1 and apoptotic or inflammatory factors was measured by RNA immunoprecipitation. Increased Malat1 levels were found in cultured mouse BMECs after OGD as well as in isolated cerebral microvessels in mice after MCAO. Silencing of Malat1 by Malat1 GapmeR significantly increased OGD-induced cell death and Caspase 3 activity in BMECs. Silencing of Malat1 also significantly aggravated OGD-induced expression of the proapoptotic factor Bim and proinflammatory cytokines MCP-1, IL-6, and E-selectin. Moreover, Malat1 KO mice presented larger brain infarct size, worsened neurological scores, and reduced sensorimotor functions. Consistent within vitrofindings, significantly increased expression of proapoptotic and proinflammatory factors was also found in the cerebral cortex of Malat1 KO mice after ischemic stroke compared with WT controls. Finally, we demonstrated that Malat1 binds to Bim and E-selectin bothin vitroandin vivoOur study suggests that Malat1 plays critical protective roles in ischemic stroke.SIGNIFICANCE STATEMENTAccumulative studies have demonstrated the important regulatory roles of microRNAs in vascular and neural damage after ischemic stroke. However, the functional significance and mechanisms of other classes of noncoding RNAs in cerebrovascular pathophysiology after stroke are less studied. Here we demonstrate a novel role of Malat1, a long noncoding RNA that has been originally identified as a prognostic marker for non-small cell lung cancer, in cerebrovascular pathogenesis of ischemic stroke. Our experiments have provided the first evidence that Malat1 plays anti-apoptotic and anti-inflammatory roles in brain microvasculature to reduce ischemic cerebral vascular and parenchymal damages. Our studies also suggest that lncRNAs can be therapeutically targeted to minimize poststroke brain damage.
authors.affiliation: Pittsburgh Institute of Brain Disorders and Recovery, Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, and.
authors.forename: Xuejing
authors.identifier: 0000-0003-2994-5502
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Pittsburgh Institute of Brain Disorders and Recovery, Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, and.
authors.forename: Xuelian
authors.initials: X
authors.lastname: Tang
authors.affiliation: Pittsburgh Institute of Brain Disorders and Recovery, Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, and.
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana 70112.
authors.forename: Milton H
authors.initials: MH
authors.lastname: Hamblin
authors.affiliation: Pittsburgh Institute of Brain Disorders and Recovery, Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, and yink2@upmc.edu.
authors.forename: Ke-Jie
authors.identifier: 0000-0002-7169-3858
authors.initials: KJ
authors.lastname: Yin
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001921:Brain / Q000473:pathology*; D020520:Brain Infarction / Q000209:etiology; D016923:Cell Death / Q000235:genetics; D015687:Cell Hypoxia / Q000502:physiology; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000378:metabolism; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics*; D005947:Glucose / Q000172:deficiency; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D055806:Microvessels / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D062085:RNA, Long Noncoding / Q000235:genetics / Q000378:metabolism*; D015427:Reperfusion Injury; D013997:Time Factors
chemical_list: D016207:Cytokines; C557040:Malat1 long non-coding RNA, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D062085:RNA, Long Noncoding; D005947:Glucose
keywords: Malat1; apoptosis; cerebral ischemia; cerebral vascular endothelial cell; inflammation; stroke