title: Pathological Effects of Mutant C1QTNF5 (S163R) Expression in Murine Retinal Pigment Epithelium.
abstract: OBJECTIVE
  The mutation S163R in complement C1q tumor necrosis factor-related protein-5 (C1QTNF5) causes an autosomal dominant disorder known as late-onset retinal degeneration (L-ORD). In this study, our goal is to evaluate the consequences of mutant S163R C1QTNF5 expression in mouse RPE following its delivery using an adeno-associated viral (AAV) vector.
  
  
  METHODS
  We generated AAV vectors containing either human wild-type C1QTNF5 or mutant S163R C1QTNF5 driven by an RPE-specific BEST1 promoter, and delivered them subretinally into one eye of adult C57BL/6 mice. Transgene expression was detected by immunohistochemistry. Retinal function was assessed by full-field ERG. Pathological changes were further examined by digital fundus imaging and spectral-domain optical coherence tomography (SD-OCT).
  
  
  RESULTS
  We show that the AAV-expressed mutant S163R leads to pathological effects similar to some of those found in patients with advanced L-ORD, including RPE thinning, RPE cell loss, and retinal degeneration. In addition, we provide in vivo evidence that mutant S163R C1QTNF5 can form large, transparent, spherical intracellular aggregates throughout the RPE, which are detectable by light microscopy. In contrast to AAV-expressed wild-type C1QTNF5, which is secreted apically from the RPE toward the photoreceptor cells and the outer limiting membrane, the S163R mutant is primarily routed toward the basal side of RPE, where it forms thick, extracellular deposits over time.
  
  
  CONCLUSIONS
  Adeno-associated viral-targeted expression of mutant S163R in the RPE represents a useful approach for quickly generating animal models that mimic pathological features of L-ORD and offers the potential to understand disease mechanisms and develop therapeutic strategies.
authors.forename: Astra
authors.initials: A
authors.lastname: Dinculescu
authors.forename: Seok-Hong
authors.initials: SH
authors.lastname: Min
authors.forename: Frank M
authors.initials: FM
authors.lastname: Dyka
authors.forename: Wen-Tao
authors.initials: WT
authors.lastname: Deng
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Stupay
authors.forename: Vince
authors.initials: V
authors.lastname: Chiodo
authors.forename: W Clay
authors.initials: WC
authors.lastname: Smith
authors.forename: William W
authors.initials: WW
authors.lastname: Hauswirth
mesh_terms: D000818:Animals; D000075002:Bestrophins; D015153:Blotting, Western; D005136:Eye Proteins / Q000235:genetics; D005654:Fundus Oculi; D015870:Gene Expression; D007473:Ion Channels / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D020125:Mutation, Missense; D012162:Retinal Degeneration / Q000235:genetics; D055213:Retinal Pigment Epithelium / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D041623:Tomography, Optical Coherence
chemical_list: C491856:Best1 protein, mouse; D000075002:Bestrophins; C516596:CTRP5 protein, mouse; D005136:Eye Proteins; D007473:Ion Channels; D008565:Membrane Proteins