title: Mechanisms of AAV transduction in glaucoma-associated human trabecular meshwork cells.
abstract: BACKGROUND
  Glaucoma is a chronic eye disease which leads to irreversible blindness. The trabecular meshwork tissue controls intraocular pressure (IOP), which is the major risk factor for glaucoma. Gene therapy treatment of chronic diseases requires the use of long-term expression, low toxicity and lack of immune response vectors. Adeno-associated viruses (AAV) possess these characteristics but have been unable to transduce the trabecular meshwork. Because of the importance of regulating elevated IOP by long-term gene therapy, we investigated mechanisms of AAV transduction to the human trabecular meshwork (TM).
  
  
  METHODS
  Primary human trabecular meshwork cells (HTM) and perfused organ cultures were infected with rAAV2-GFP, RGD-pseudotyped rAAV2-GFP alone, or combined with recombinant DeltaE1/E3 adenoviruses. Intracellular rAAV2 DNA and RNA were measured by relative quantitative and real-time TaqMan polymerase chain reaction (PCR). Host transcriptome was analyzed using high-density oligonucleotide microarrays. One transduction mechanism was tested using self-complementary AAV (scAAV).
  
  
  RESULTS
  The dramatic transduction enhancement obtained upon co-infection of rAAV2 with DeltaE1/E3 adenoviruses provides insights into transduction mechanisms in the HTM. Even if not transduced, rAAV2 enters TM cells. GeneChip analysis showed significant changes in host genes involved in cell cycle and DNA replication. Consequently, scAAV-GFP transduction was highly efficient. Other transduction-enhancement genes included coxsackie adenovirus receptor (CAR) and genes relevant to trabecular meshwork function.
  
  
  CONCLUSIONS
  The rate-limiting step of AAV transduction was not viral entry failure but, at least in part, host downregulation of DNA replication. Additional specific host genes might be involved. Our study revealed genes and mechanisms which led for the first time to efficient AAV transduction of the HTM.
authors.affiliation: Department of Ophthalmology, University of North Carolina School of Medicine, 103 Mason Farm Road, Chapel Hill, NC 27599, USA. tborras@med.unc.edu
authors.forename: Teresa
authors.initials: T
authors.lastname: Borrás
authors.forename: Wei
authors.initials: W
authors.lastname: Xue
authors.forename: Vivian W
authors.initials: VW
authors.lastname: Choi
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Bartlett
authors.forename: Guorong
authors.initials: G
authors.lastname: Li
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Samulski
authors.forename: Sarah S
authors.initials: SS
authors.lastname: Chisolm
mesh_terms: D000867:Anterior Chamber / Q000378:metabolism / Q000473:pathology; D002460:Cell Line; D000229:Dependovirus / Q000235:genetics*; D020869:Gene Expression Profiling; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D005901:Glaucoma / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D007429:Intraocular Pressure / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D009924:Organ Culture Techniques; D010477:Perfusion; D014129:Trabecular Meshwork / Q000378:metabolism / Q000473:pathology*; D014161:Transduction, Genetic
chemical_list: D049452:Green Fluorescent Proteins