title: Downregulation of VEGF mRNA expression by triamcinolone acetonide acetate-loaded chitosan derivative nanoparticles in human retinal pigment epithelial cells.
abstract: BACKGROUND
  The purpose of this study was to investigate the downregulation of mRNA expression of vascular endothelial growth factor (VEGF) by triamcinolone acetonide acetate (TAA)-loaded chitosan nanoparticles in human retinal pigment epithelial cells.
  
  
  METHODS
  TAA-loaded deoxycholic acid-modified chitosan (TAA/DA-Chit) nanoparticles were prepared via a self-assembly mechanism, and their morphology and zeta potential were examined by transmission electron microscopy and zeta potential analysis, respectively. DA-Chit and TAA/DA-Chit nanoparticle toxicity was evaluated using a Cell Counting Kit-8 assay. The efficiency of cellular uptake was determined using fluorescein isothiocyanate-labeled DA-Chit nanoparticles, in place of TAA/DA-Chit nanoparticles, assessed by both inverted fluorescence microscopy and flow cytometry. Downregulation of VEGF mRNA expression by TAA/DA-Chit nanoparticles was further investigated by real-time reverse transcription polymerase chain reaction (RT-PCR) assay of the treated human retinal pigment epithelial cells.
  
  
  RESULTS
  TAA/DA-Chit nanoparticles were prepared with a TAA-loading capacity in the range of 12%-82%, which increased the water solubility of TAA from 0.3 mg/mL to 2.1 mg/mL. These nanoparticles showed oblate shapes 100-550 nm in size in transmission electron microscopic images and had positive zeta potentials. The Cell Counting Kit-8 assay indicated that the DA-Chit and TAA/DA-Chit nanoparticles had no toxicity and low toxicity, respectively, to human retinal pigment epithelial cells. Fluorescein isothiocyanate-labeled DA-Chit nanoparticle uptake by human retinal pigment epithelial cells was confirmed by inverted fluorescence microscopy and flow cytometry. Real-time RT-PCR assay showed that the VEGF mRNA level decreased after incubation of human retinal pigment epithelial cells with TAA/DA-Chit nanoparticles.
  
  
  CONCLUSIONS
  TAA/DA-Chit nanoparticles had a downregulating effect on VEGF mRNA expression in human retinal pigment epithelial cells and low cytotoxicity, which might be beneficial characteristics for the development of future treatment for diabetic retinopathy.
authors.affiliation: Department of Ophthalmology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China.
authors.forename: Huaisheng
authors.initials: H
authors.lastname: Zhou
authors.forename: Liqun
authors.initials: L
authors.lastname: Yang
authors.forename: Huajie
authors.initials: H
authors.lastname: Li
authors.forename: Haijun
authors.initials: H
authors.lastname: Gong
authors.forename: Liangzheng
authors.initials: L
authors.lastname: Cheng
authors.forename: Haisheng
authors.initials: H
authors.lastname: Zheng
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Zhang
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Lan
mesh_terms: D000085:Acetates / Q000494:pharmacology; D002460:Cell Line; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry* / Q000494:pharmacology; D003840:Deoxycholic Acid / Q000737:chemistry / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D053758:Nanoparticles / Q000008:administration & dosage / Q000737:chemistry*; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D012995:Solubility; D014222:Triamcinolone Acetonide / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D000085:Acetates; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D003840:Deoxycholic Acid; D048271:Chitosan; D014222:Triamcinolone Acetonide