June 2022
Volume 63, Issue 7
Open Access
ARVO Annual Meeting Abstract  |   June 2022
Thrombospondin-1 p.R1034 missense alleles cause congenital glaucoma with variable expressivity by inducing extracellular protein aggregation
Author Affiliations & Notes
  • Haojie Fu
    Department of Surgery, Boston Children's Hospital, Boston, Massachusetts, United States
    Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
  • Owen Siggs
    Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
    Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
  • Lachlan Knight
    Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
  • Sandra E Staffieri
    Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
    Department of Surgery, University of Melbourne, Parkville, Victoria, Australia
  • Jonathan B Ruddle
    Department of Ophthalmology, Royal Children’s Hospital, Parkville, Victoria, Australia
  • Amy E Birsner
    Department of Surgery, Boston Children's Hospital, Boston, Massachusetts, United States
  • Edward Ryan Collantes
    Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
    Department of Ophthalmology, Massachusetts Eye and Ear, Boston, Massachusetts, United States
  • Jamie Craig
    Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
  • Janey L Wiggs
    Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
    Department of Ophthalmology, Massachusetts Eye and Ear, Boston, Massachusetts, United States
  • Robert J D'Amato
    Department of Surgery, Boston Children's Hospital, Boston, Massachusetts, United States
    Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
  • Footnotes
    Commercial Relationships   Haojie Fu None; Owen Siggs None; Lachlan Knight None; Sandra Staffieri None; Jonathan Ruddle None; Amy Birsner None; Edward Ryan Collantes None; Jamie Craig None; Janey Wiggs None; Robert D'Amato None
  • Footnotes
    Support  NIH/NEI R01 EY031820
Investigative Ophthalmology & Visual Science June 2022, Vol.63, 805. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Haojie Fu, Owen Siggs, Lachlan Knight, Sandra E Staffieri, Jonathan B Ruddle, Amy E Birsner, Edward Ryan Collantes, Jamie Craig, Janey L Wiggs, Robert J D'Amato; Thrombospondin-1 p.R1034 missense alleles cause congenital glaucoma with variable expressivity by inducing extracellular protein aggregation. Invest. Ophthalmol. Vis. Sci. 2022;63(7):805.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose : Few genes are known to cause early-onset glaucoma, a severe disease affecting children and young adults. The overall purpose of this work is to identify novel early-onset glaucoma genes.

Methods : Whole-exome sequencing (WES) was conducted to identify variants in glaucoma families. A CRISPR-mediated mouse germline knock-in strategy was used to create a mutation equivalent to THBS1 R1034C. Mutant mice were evaluated for intraocular pressure (IOP), outflow facility, anterior segment histology and RGCs counts. The force field program-FoldX was used to determine the protein folding energy changes related to different mutations. The effect of mutations on extracellular matrix (ECM) was studied by site directed mutagenesis and in vitro expression.

Results : We identified novel heterozygous THBS1 missense alleles altering p.Arg1034, a highly conserved amino acid, in 3 unrelated and ethnically diverse families affected by congenital glaucoma with variable expressivity (two families with R1034C and one with R1034S). Both heterozygous and homozygous Thbs1R1034C mice exhibited elevated IOP (ANOVA, P<0.001), decreased aqueous outflow facility (43.3% and 40.5%, respectively), and RGCs loss (15.9% reduction in central retina and 22.2% in the peripheral), compared to wild type controls. Histology and electron microscopy revealed an aberrant accumulation of THBS1 in the TM ECM. FoldX suggested that the missense alleles destabilize the THBS1 structure causing protein aggregation by misfolding. Analysis using a mutagenesis series at Arg1034, including R1034C and R1034S, showed that the extent of THBS1 aggregation in ECM is correlated with the extent of mutation-related free unfolding energy. Structural ECM components, especially fibronectin, were also recruited to THBS1 depositions.

Conclusions : Our study suggests that missense variants altering THBS1 p.Arg1034 can elevate IOP through a mechanism involving aberrant TM extracellular THBS1 aggregation with compromised outflow. The role of THBS1 in the regulation of aqueous humor dynamics provides new opportunities for genetic testing and therapeutic intervention.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×