title: Effect of PEGylation on biodistribution and gene silencing of siRNA/lipid nanoparticle complexes.
abstract: OBJECTIVE
  To determine the influence of physicochemical properties of lipid nanoparticles (LNPs) carrying siRNA on their gene silencing in vivo. Mechanistic understanding of how the architecture of the nanoparticle can alter gene expression has also been studied.
  
  
  METHODS
  The effect of 3-N-[(ω-methoxypoly(ethylene glycol)2000)carbamoyl]-1,2-dimyristyloxy-propylamine (PEG-C-DMA) on hepatic distribution and FVII gene silencing was determined. FVII mRNA in hepatocytes and liver tissues was determined by Q-PCR. Hepatic distribution was quantified by FACS analysis using Cy5 labeled siRNA.
  
  
  RESULTS
  Gene silencing was highly dependent on the amount of PEG-C-DMA present. FVII gene silencing inversely correlated to the amount of PEG-C-DMA in LNPs. High FVII gene silencing was obtained in vitro and in vivo when the molar ratio of PEG-C-DMA to lipid was 0.5 mol%. Surprisingly, PEGylation didn't alter the hepatic distribution of the LNPs at 5 h post administration. Instead the amount of PEG present in the LNPs has an effect on red blood cell disruption at low pH.
  
  
  CONCLUSIONS
  Low but sufficient PEG-C-DMA amount in LNPs plays an important role for efficient FVII gene silencing in vivo. PEGylation did not alter the hepatic distribution of LNPs, but altered gene silencing efficacy by potentially reducing endosomal disruption.
authors.affiliation: Biomedical Engineering and Technology Institute Institutes for Advanced Interdisciplinary Research, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062, China.
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Bao
authors.forename: Yi
authors.initials: Y
authors.lastname: Jin
authors.forename: Padmanabh
authors.initials: P
authors.lastname: Chivukula
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Clamme
authors.forename: Ram I
authors.initials: RI
authors.lastname: Mahato
authors.forename: Dominic
authors.initials: D
authors.lastname: Ng
authors.forename: Wenbin
authors.initials: W
authors.lastname: Ying
authors.forename: Yiting
authors.initials: Y
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Yu
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005167:Factor VII / Q000235:genetics*; D022781:Hepatocytes / Q000378:metabolism*; D008055:Lipids / Q000737:chemistry; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011437:Propylamines / Q000737:chemistry; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D008055:Lipids; D011437:Propylamines; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011092:Polyethylene Glycols; D005167:Factor VII; C028210:monomethoxypolyethylene glycol