title: Flank sequences of miR-145/143 and their aberrant expression in vascular disease: mechanism and therapeutic application.
abstract: BACKGROUND
  Many microRNAs (miRNAs) are downregulated in proliferative vascular disease. Thus, upregulation of these miRNAs has become a major focus of research activity. However, there is a critical barrier in gene therapy to upregulate some miRNAs such as miR-145 and miR-143 because of their significant downregulation by the unclear endogenous mechanisms under disease conditions. The purpose of this study was to determine the molecular mechanisms responsible for their downregulation and to overcome the therapeutic barrier.
  
  
  RESULTS
  In cultured proliferative rat vascular smooth muscle cells (VSMCs) in vitro and in diseased rat and mouse arteries in vivo, we have identified that the impairment of pri-miR-145 into pre-miR-145 is the critical step related to the downregulation of miR-145, in which the PI3-kinase/Akt/p53 pathway is involved. We further identified that the flank sequences of pri-miR-145 are the critical structural components responsible for the aberrant miR-145 expression. Switching of the flank sequence of downregulated miR-145 and miR-143 to the flank sequence of miR-31 confers resistance to their downregulation. The genetically engineered miR-145 (smart miR-145) restored the downregulated miR-145 in proliferative rat VSMCs and in rat carotid arteries with balloon injury and mouse atherosclerotic aortas and demonstrated much better therapeutic effects on the abnormal growth of VSMCs, expression of its target gene, KLF5 expression, VSMC marker gene expression, and vascular neointimal growth.
  
  
  CONCLUSIONS
  The flank sequences of miR-145 and miR-143 play a critical role in their aberrant expression in VSMCs and vascular walls. The genetically engineered "smart" miRNAs based on their flank sequences may have broadly therapeutic applications for many vascular diseases.
authors.affiliation: Department of Pharmacology and Cardiovascular Research Center, Rush University Medical Center, Chicago, IL.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Liu
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Cheng
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Shanshan
authors.initials: S
authors.lastname: Qin
authors.forename: Xiuwei
authors.initials: X
authors.lastname: Chen
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Tang
authors.forename: Xiangyu
authors.initials: X
authors.lastname: Zhou
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Krall
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics; D050197:Atherosclerosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D020212:Carotid Artery Injuries / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D021901:DNA, Intergenic; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism* / Q000627:therapeutic use; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D058426:Neointima; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034622:RNA Interference; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D001057:Apolipoproteins E; D021901:DNA, Intergenic; C492215:Klf5 protein, rat; D051741:Kruppel-Like Transcription Factors; C569508:MIRN143 microRNA, rat; C543499:MIRN145a microRNA, mouse; C542511:MIRN145 microRNA, rat; D035683:MicroRNAs; C532884:MIRN143 microRNA, mouse; D016159:Tumor Suppressor Protein p53; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt
keywords: cell growth; gene expression; microRNAs; smart microRNAs; vascular disease