title: MicroRNA-9 induces defective trafficking of Nav1.1 and Nav1.2 by targeting Navβ2 protein coding region in rat with chronic brain hypoperfusion.
abstract: BACKGROUND
  Previous studies have demonstrated that the trafficking defects of Nav1.1/Nav1.2 are involved in the dementia pathophysiology. However, the detailed mechanisms are not fully understood. Moreover, whether the impaired miRNAs regulation linked to dementia is a key player in sodium channel trafficking disturbance remains unclear. The cognitive impairment induced by chronic cerebral ischemia through chronic brain hypoperfusion (CBH) is likely reason to precede dementia. Therefore, our goal in the present study was to examine the role of microRNA-9 (miR-9) in regulating Nav1.1/Nav1.2 trafficking under CBH generated by bilateral common carotid artery occlusion (2VO).
  
  
  RESULTS
  The impairment of Nav1.1/Nav1.2 trafficking and decreased expression of Navβ2 were found in the hippocampi and cortices of rats following CBH generated by bilateral 2VO. MiR-9 was increased in both the hippocampi and cortices of rats following CBH by qRT-PCR. Intriguingly, miR-9 suppressed, while AMO-miR-9 enhanced, the trafficking of Nav1.1/Nav1.2 from cytoplasm to cell membrane. Further study showed that overexpression of miR-9 inhibited the Navβ2 expression by targeting on its coding sequence (CDS) domain by dual luciferase assay. However, binding-site mutation or miR-masks failed to influence Navβ2 expression as well as Nav1.1/Nav1.2 trafficking process, indicating that Navβ2 is a potential target for miR-9. Lentivirus-mediated miR-9 overexpression also inhibited Navβ2 expression and elicited translocation deficits to cell membrane of Nav1.1/Nav1.2 in rats, whereas injection of lentivirus-mediated miR-9 knockdown could reverse the impaired trafficking of Nav1.1/Nav1.2 triggered by 2VO.
  
  
  CONCLUSIONS
  We conclude that miR-9 may play a key role in regulating the process of Nav1.1/Nav1.2 trafficking via targeting on Navβ2 protein in 2VO rats at post-transcriptional level, and inhibition of miR-9 may be a potentially valuable approach to prevent Nav1.1/Nav1.2 trafficking disturbance induced by CBH.
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China. sunlihua0219@163.com.
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: Sun
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Mei-Ling
authors.initials: ML
authors.lastname: Yan
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Xue-Ling
authors.initials: XL
authors.lastname: Hu
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Li-Wei
authors.initials: LW
authors.lastname: Peng
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Che
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Bao
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Guo
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Ban
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Harbin Medical University, No.157 Baojian Road, Nangang District, Harbin, Heilongjiang Province, 150081, China.
authors.forename: Huai-Lei
authors.initials: HL
authors.lastname: Liu
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Harbin Medical University, No.157 Baojian Road, Nangang District, Harbin, Heilongjiang Province, 150081, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Hou
authors.affiliation: Department of Pharmacology, Harbin Medical University, No.157 Baojian Road, Nangang District,Harbin, Heilongjiang Province, 15008, China. aijing@ems.hrbmu.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Ai
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000235:genetics / Q000378:metabolism*; D017536:Carotid Artery, Common; D002540:Cerebral Cortex / Q000378:metabolism; D002908:Chronic Disease; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D005822:Genetic Vectors / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism; D016086:Lentivirus / Q000235:genetics; D008026:Ligation; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000494:pharmacology*; D062550:NAV1.1 Voltage-Gated Sodium Channel / Q000235:genetics / Q000378:metabolism*; D062551:NAV1.2 Voltage-Gated Sodium Channel / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism; D061567:Voltage-Gated Sodium Channel Blockers; D062548:Voltage-Gated Sodium Channel beta-2 Subunit / Q000096:biosynthesis / Q000235:genetics
chemical_list: C582333:MIRN9 microRNA, rat; D035683:MicroRNAs; D062550:NAV1.1 Voltage-Gated Sodium Channel; D062551:NAV1.2 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; D016376:Oligonucleotides, Antisense; C568250:Scn1a protein, rat; D061567:Voltage-Gated Sodium Channel Blockers; D062548:Voltage-Gated Sodium Channel beta-2 Subunit; D012964:Sodium