June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Rod photoreceptor-specific ablation of dehydrodolichyldiphosphate synthase (DHDDS) causes rapid retinal degeneration: A new model for arRP
Author Affiliations & Notes
  • Sriganesh Ramachandra Rao
    Biochemistry, SUNY- University at Buffalo, Buffalo, New York, United States
    Research Service, VA Western NY Healthcare System, Buffalo, New York, United States
  • Mark Christian Butler
    Ophthalmology, Physiology & Biophysics, Pharmacology & Toxicology, and Neuroscience Program, SUNY- University at Buffalo, Buffalo, New York, United States
    Research Service, VA Western NY Healthcare System, Buffalo, New York, United States
  • Delores A. Stacks
    Optometry and Vision Science, University of Alabama, Birmingham, Birmingham, Alabama, United States
  • Steven J Pittler
    Optometry and Vision Science, University of Alabama, Birmingham, Birmingham, Alabama, United States
  • Jack M Sullivan
    Ophthalmology, Physiology & Biophysics, Pharmacology & Toxicology, and Neuroscience Program, SUNY- University at Buffalo, Buffalo, New York, United States
    Research Service, VA Western NY Healthcare System, Buffalo, New York, United States
  • Steven J Fliesler
    Ophthalmology, Biochemisty, & Neuroscience Program, SUNY- University at Buffalo, Buffalo, New York, United States
    Research Service, VA Western NY Healthcare System, Buffalo, New York, United States
  • Footnotes
    Commercial Relationships   Sriganesh Ramachandra Rao, None; Mark Butler, None; Delores Stacks, None; Steven Pittler, None; Jack Sullivan, None; Steven Fliesler, None
  • Footnotes
    Support  NIH RO1 EY007361 (SJF); NIH R01 EY013433 (JMS); NIH R01 EY018143 and NIH P30 EY003039 (SJP); RPB Unrestricted Grant (SJF, JMS); Fight for Sight Student Summer Fellowship (SRR); Dept. of Veterans Affairs (SJF, SRR, MCB, JMS); Research Career Scientist (SJF).
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 265. doi:
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    • Get Citation

      Sriganesh Ramachandra Rao, Mark Christian Butler, Delores A. Stacks, Steven J Pittler, Jack M Sullivan, Steven J Fliesler; Rod photoreceptor-specific ablation of dehydrodolichyldiphosphate synthase (DHDDS) causes rapid retinal degeneration: A new model for arRP. Invest. Ophthalmol. Vis. Sci. 2017;58(8):265.

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

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Abstract

Purpose : DHDDS catalyzes cis-prenyl chain elongation to produce dolichylpyrophosphate, which is required for N-glycosylation of proteins (e.g., rhodopsin). Human mutations in DHDDS have been implicated in autosomal recessive Retinitis Pigmentosa (arRP). We examined the effects of rod-specific Dhdds ablation on the structural and electrophysiological function of the mouse retina.

Methods : A floxed Dhdds construct (KOMP, U.C. Davis) was incorporated into mouse ES cells, and a Dhdds-flx/flx mouse (C57BL/6J) line was generated. These mice were crossed with Rho-Cre (iCre-75) mice (Jackson Labs) to generate a rod-specific Dhdds knockout line (rod-Dhdds-ko). Specificity and efficiency of cre recombinase expression and activity were verified by crossing Rho-Cre mice with loxP-STOP-loxP EGFP reporter mice (Jackson Labs). Electroretinography (ERG) and spectral domain-optical coherence tomography (SD-OCT) measurements were obtained from rod-Dhdds-ko and age-matched control C57BL/6J (n=3/group) mice between postnatal (PN) wk 4 and 6. Animals were euthanized, and tissues were harvested for histological and immunohistochemical analyses. Quantitative data (mean/S.D.) were statistically compared using Student’s t-test (significance: p≤0.05) or one-way ANOVA.

Results : Cre recombinase was active in >95% of rods by PN 4 wk. Outer nuclear layer (ONL) thickness (by SD-OCT) was comparable in both rod-Dhdds-ko and control mice at PN 4 wk. However, by PN 5 wk, ONL thickness was reduced by ca. 50% in rod-Dhdds-ko mice; by PN 6 wk, only 1-2 ONL rows remained, with sparse anti-opsin immunoreactivity and little or no outer segments remaining. Scotopic and photopic ERG responses in rod-Dhdds-ko mice at PN 4 wk mice were comparable to controls, but were extinguished at all flash intensities by PN 6 wk.

Conclusions : Rod-specific Dhdds ablation did not compromise early postnatal retinal development, but caused rapid retinal degeneration between PN 4-6 wk. These findings underscore the importance of lipid-linked protein N-glycosylation in the retina, and present a new and potentially useful mouse model of arRP, e.g., for elucidation of pathobiology mechanisms, gene therapy preclinical studies, etc.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

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