title: Nanoparticle-mediated delivery of therapeutic genes: focus on miRNA therapeutics.
abstract: BACKGROUND
  Micro RNAs (miRNA) are 21 - 23 nucleotides long and regulate the expression of coding genes by binding imperfectly with their 3' UTR region. The miRNA profile is altered in pathological processes, making miRNAs good targets for drug therapy. Restoration of down-regulated miRNA or inhibition of overexpressed miRNA to return miRNA to its normal state is the basis of miRNA-based therapy. This review focuses on nanocarriers used for the delivery of miRNA that confer physical stability to the unstable RNA structure, protect the RNA from nuclease degradation and aid in effective silencing of target genes.
  
  
  METHODS
  The necessity of the nanocarrier for the delivery of the miRNA is emphasized and the recent research on liposome-, metal- and polymer-mediated miRNA delivery for the inhibition or replacement of the disease-related miRNA is summarized.
  
  
  CONCLUSIONS
  The size, charge and surface properties of nanocarriers have to be tuned to ensure effective and safe delivery of the miRNA in clinical practice. The immune responses related to the nanocarriers and the double-stranded nucleotide delivery remain to be addressed. Also, the binding of miRNAs to non-specific targets has to be studied in more detail because miRNAs have multiple targets due to partial binding unlike siRNA.
authors.affiliation: Chonnam National University Medical School, Research Institute of Medical Sciences, Department of Biomedical Science, Gwangju, South Korea. pik96@chonnam.ac.kr
authors.forename: Muthunarayanan
authors.initials: M
authors.lastname: Muthiah
authors.forename: In-Kyu
authors.initials: IK
authors.lastname: Park
authors.forename: Chong-Su
authors.initials: CS
authors.lastname: Cho
mesh_terms: D000818:Animals; D016503:Drug Delivery Systems; D015316:Genetic Therapy; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D053758:Nanoparticles / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D035683:MicroRNAs; D034741:RNA, Small Interfering