9-cis-retinal and Retinal-Degeneration

Rhodopsin homeostasis is tightly coupled to rod photoreceptor cell survival and vision. Mutations resulting in the misfolding of rhodopsin can lead to autosomal dominant retinitis pigmentosa (adRP), a progressive retinal degeneration that currently is untreatable. Using a cell-based high-throughput screen (HTS) to identify small molecules that can stabilize the P23H-opsin mutant, which causes most cases of adRP, we identified a novel pharmacological chaperone of rod photoreceptor opsin, YC-001. As a non-retinoid molecule, YC-001 demonstrates micromolar potency and efficacy greater than 9-cis-retinal with lower cytotoxicity. YC-001 binds to bovine rod opsin with an EC

Topics: Alcohol Oxidoreductases; Animals; ATP-Binding Cassette Transporters; Cell Line, Tumor; Disease Models, Animal; Diterpenes; Female; HEK293 Cells; High-Throughput Screening Assays; Humans; Light; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mutation; Neuroprotective Agents; NIH 3T3 Cells; Protein Folding; Protein Transport; Retinal Degeneration; Retinal Rod Photoreceptor Cells; Retinaldehyde; Rhodopsin; Thiophenes; Treatment Outcome

Continuous regeneration of the 11-

Topics: Alcohol Oxidoreductases; Animals; ATP-Binding Cassette Transporters; Diterpenes; Light; Macular Degeneration; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Opsins; Protective Agents; Retina; Retinal Degeneration; Retinaldehyde; Retinoids

To assess changes in rod and cone visual functions in a mouse model of Fundus albipunctatus with disrupted 11-cis-retinol dehydrogenase (RDH) genes after pharmacologic treatment with an artificial retinal chromophore.. Retinoid levels and photoreceptor functions of Rdh5-/-Rdh11-/- mice at a variety of light intensities were analyzed with normal-phase HPLC and ERG techniques. Production of 11-cis-retinal, the visual pigment chromophore, was suppressed with a potent inhibitor of the retinoid cycle, all-trans-retinylamine (Ret-NH2). The chromophore was replaced by a functional geometric isomer, 9-cis-retinal, delivered by oral gavage.. Aberrant cone responses were detected in 12-month-old Rdh5-/-Rdh11-/- mice raised in a 12-hour light/12-hour dark cycle. This cone defect was exacerbated in conditions of low levels of 11-cis-retinal. Administration of 9-cis-retinal increased the rate of dark adaptation and improved cone function in Rdh5-/-Rdh11-/- mice.. Disruption of 11-cis-RDHs causes a slowly developing cone dystrophy caused by inefficient cone pigment regeneration. Rod and cone visual function improved significantly in the mouse model of F. albipunctatus after treatment with 9-cis-retinal, suggesting a potential approach to slow the progression of cone dystrophy in affected humans.

Topics: Animals; Chromatography, High Pressure Liquid; Dark Adaptation; Disease Models, Animal; Diterpenes; Electroretinography; Isomerism; Mice; Mice, Knockout; Oxidoreductases; Photoreceptor Cells, Vertebrate; Pigment Epithelium of Eye; Retinal Degeneration; Retinal Dehydrogenase; Retinaldehyde; Retinoids

RPE65 is essential for the generation of 11-cis retinal. Rod photoreceptors in the RPE65-knockout (Rpe65(-/-)) mouse are known to degenerate slowly with age. This study was designed to examine cone photoreceptors and the expression of cone-specific genes in the Rpe65(-/-) mouse.. Gene expression changes were identified by microarray and confirmed by real-time RT-PCR. Cone photoreceptors were stained by peanut agglutinin (PNA) lectin in the flatmounted retina. The 9- or 11-cis retinal was supplied by intraperitoneal injections.. The short-wavelength (SWL) cone opsin mRNA was markedly decreased at 2 weeks of age, whereas the decrease in the middle-wavelength (MWL) cone opsin mRNA occurred relatively later in age. In contrast, the rhodopsin mRNA level did not show any significant change at all the ages analyzed. Consistent with the cone opsin changes, the cone transducin alpha-subunit mRNA decreased at both 4 and 8 weeks of age, whereas again the rod transducin alpha-subunit did not show any significant change. Rpe65(-/-) mice showed significant cone loss in both the central and ventral retina between 2 and 3 weeks of age. Administration of 9- or 11-cis retinal to Rpe65(-/-) mice 2 weeks of age increased cone density by twofold in these areas.. In the Rpe65(-/-) mouse, the expression of cone-specific genes is downregulated and is accompanied by cone degeneration at early ages. Early administration of 9- or 11-cis retinal can partially prevent cone loss, suggesting that the absence of 11-cis chromophore may be responsible for the early cone degeneration.

Topics: Animals; Carrier Proteins; Cell Count; cis-trans-Isomerases; Diterpenes; Down-Regulation; Eye Proteins; Gene Expression; Gene Expression Profiling; GTP-Binding Protein alpha Subunits; Heterotrimeric GTP-Binding Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Oligonucleotide Array Sequence Analysis; Proteins; Retinal Cone Photoreceptor Cells; Retinal Degeneration; Retinaldehyde; Reverse Transcriptase Polymerase Chain Reaction; Rhodopsin; RNA, Messenger; Rod Opsins; Transducin

To determine the impairment of the transient pupillary light reflex (TPLR) due to severe retinal dysfunction and degeneration in a murine model of Leber congenital amaurosis (LCA) and in patients with the disease.. Direct TPLR was elicited in anesthetized, dark-adapted Rpe65(-/-) and control mice with full-field light stimuli (0.1 second duration) of increasing intensities (-6.6 to +2.3 log scot-cd. m(-2)). 9-cis-Retinal was administered orally to a subset of Rpe65(-/-) mice, and TPLR was recorded 48 hours after the treatment. TPLR was also measured in a group of patients with LCA.. Baseline pupillary diameters in Rpe65(-/-) and control mice were similar. TPLR thresholds of Rpe65(-/-) mice were elevated by 5 log units compared with those of control animals. The waveform of the TPLR in Rpe65(-/-) mice was similar to that evoked by 4.8-log-unit dimmer stimuli in control mice. Treatment of Rpe65(-/-) mice with 9-cis-retinal lowered the TPLR threshold by 2.1 log units. Patients with LCA had baseline pupillary diameters similar to normal, but the TPLR was abnormal, with thresholds elevated by 3 to more than 6 log units. When adjusted to the elevation of TPLR threshold, pupillary constriction kinetics in most patients were similar to those in normal subjects.. Pupillometry was used to quantify visual impairment and to probe transmission of retinal signals to higher nervous centers in a murine model of LCA and in patients with LCA. Mouse results were consistent with a dominant role of image-forming photoreceptors driving the early phase of the TPLR when elicited by short-duration stimuli. The objective and noninvasive nature of the TPLR measurement, and the observed post-treatment change toward normal in the animal model supports the notion that this may be a useful outcome measure in future therapeutic trials of LCA.

Topics: Adolescent; Adult; Animals; Blindness; Carrier Proteins; Child; Child, Preschool; cis-trans-Isomerases; Dark Adaptation; Diterpenes; Electrophysiology; Eye Proteins; Female; Humans; Infant; Light; Male; Mice; Mice, Knockout; Middle Aged; Proteins; Pupil Disorders; Reflex, Pupillary; Retinal Degeneration; Retinaldehyde

Mutations in the retinal pigment epithelium gene encoding RPE65 are a cause of the incurable early-onset recessive human retinal degenerations known as Leber congenital amaurosis. Rpe65-deficient mice, a model of Leber congenital amaurosis, have no rod photopigment and severely impaired rod physiology. We analyzed retinoid flow in this model and then intervened by using oral 9-cis-retinal, attempting to bypass the biochemical block caused by the genetic abnormality. Within 48 h, there was formation of rod photopigment and dramatic improvement in rod physiology, thus demonstrating that mechanism-based pharmacological intervention has the potential to restore vision in otherwise incurable genetic retinal degenerations.

Topics: Administration, Oral; Animals; Blindness; Carrier Proteins; Child; cis-trans-Isomerases; Disease Models, Animal; Diterpenes; Eye Proteins; Female; Humans; Male; Mice; Mice, Knockout; Pigment Epithelium of Eye; Proteins; Retinal Degeneration; Retinal Rod Photoreceptor Cells; Retinaldehyde; Retinoids; Time Factors