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Nguyen MN, Chakraborty D, Rao SR, Onysk A, Radkiewicz M, Surmacz L, Swiezewska E, Soubeyrand E, Akhtar TA, Kraft TW, Sherry DM, Fliesler SJ, Pittler SJ. A Dhdds K42E knock-in RP59 mouse model shows inner retina pathology and defective synaptic transmission. Cell Death Dis 2023; 14:420. [PMID: 37443173 PMCID: PMC10345138 DOI: 10.1038/s41419-023-05936-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 06/07/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023]
Abstract
Retinitis pigmentosa (RP) defines a group of hereditary progressive rod-cone degenerations that exhibit a common phenotype caused by variants in over 70 genes. While most variants in the dehydrodolichyl diphosphate synthase (DHDDS) gene result in syndromic abnormalities, some variants cause non-syndromic RP (RP59). DHDDS encodes one subunit of the enzyme cis-prenyltransferase (CPT), which is required for the synthesis of dolichol (Dol), that is a necessary protein glycosylation cofactor. We previously reported the creation and initial characterization of a knock-in (KI) mouse model harboring the most prevalent RP59-associated DHDDS variant (K42E) to understand how defects in DHDDS lead to retina-specific pathology. This model exhibited no profound retinal degeneration, nor protein N-glycosylation defects. Here, we report that the Dol isoprenylogue species in retina, liver, and brain of the K42E mouse model are statistically shorter than in the corresponding tissues of age-matched controls, as reported in blood and urine of RP59 patients. Retinal transcriptome analysis demonstrated elevation of many genes encoding proteins involved in synaptogenesis and synaptic function. Quantitative retinal cell layer thickness measurements demonstrated a significant reduction in the inner nuclear layer (INL) and total retinal thickness (TRT) beginning at postnatal (PN) ∼2 months, progressively increasing to PN 18-mo. Histological analysis revealed cell loss in the INL, outer plexiform layer (OPL) disruption, and ectopic localization of outer nuclear layer (ONL) nuclei into the OPL of K42E mutant retinas, relative to controls. Electroretinograms (ERGs) of mutant mice exhibited reduced b-wave amplitudes beginning at PN 1-mo, progressively declining through PN 18-mo, without appreciable a-wave attenuation, relative to controls. Our results suggest that the underlying cause of DHDDS K42E variant driven RP59 retinal pathology is defective synaptic transmission from outer to inner retina.
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Affiliation(s)
- Mai N Nguyen
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Dibyendu Chakraborty
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Sriganesh Ramachandra Rao
- Research Service, VA Western New York Healthcare System, Buffalo, NY, 14215, USA
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Buffalo, NY, 14203, USA
| | - Agnieszka Onysk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Mariusz Radkiewicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Liliana Surmacz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Eric Soubeyrand
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G2W1, Canada
| | - Tariq A Akhtar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G2W1, Canada
| | - Timothy W Kraft
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - David M Sherry
- Departments of Cell Biology, Neurosurgery, and Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Steven J Fliesler
- Research Service, VA Western New York Healthcare System, Buffalo, NY, 14215, USA
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Buffalo, NY, 14203, USA
| | - Steven J Pittler
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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