A comprehensive clinical and biochemical functional study of a novel RPE65 hypomorphic mutation

PURPOSE. Later onset and progression of retinal dystrophy occur with some RPE65 missense mutations. The functional consequences of the novel P25L RPE65 mutation was correlated with its early-childhood phenotype and compared with other pathogenic missense mutations. METHODS. In addition to typical clinical tests, fundus autofluorescence (FAF), optical coherence tomography (OCT), and two-color threshold perimetry (2CTP) were measured. RPE65 mutations were screened by SSCP and direct sequencing. Isomerase activity of mutant RPE65 was assayed in 293F cells and quantified by HPLC analysis of retinoids. RESULTS. A very mild phenotype was detected in a now 7-yearold boy homozygous for the P25L mutation in RPE65. Although abnormal dark adaptation was noticed early, best corrected visual acuity was 20/20 at age 5 years and 20/30 at age 7 years. Nystagmus was absent. Cone electroretinogram (ERG) was measurable, rod ERG severely reduced, and FAF very low. 2CTP detected mainly cone-mediated responses in scotopic conditions, and light-adapted cone responses were approximately 1.5 log units below normal. High-resolution spectral domain OCT revealed morphologic changes. Isomerase activity in 293F cells transfected with RPE65/P25L was reduced to 7.7% of wild-type RPE65-transfected cells, whereas RPE65/ L22P-transfected cells had 13.5%. CONCLUSIONS. The mild clinical phenotype observed is consistent with the residual activity of a severely hypomorphic mutant RPE65. Reduction to Ͻ10% of wild-type RPE65 activity by homozygous P25L correlates with almost complete rod function loss and cone amplitude reduction. Functional survival of cones is possible in patients with residual RPE65 isomerase activity. This patient should profit most from gene therapy. (Invest Ophthalmol Vis Sci. 2008;49:5235-5242) DOI: 10.1167/iovs.07-1671 H uman mutations in the gene for the highly preferentially expressed RPE protein RPE65 are associated with a spectrum of retinal dystrophies ranging from more severe earlyonset conditions, variously described as Leber congenital amaurosis type 2/autosomal recessive childhood-onset severe retinal dystrophy or early-onset severe retinal dystrophy (LCA2/arCSR, EOSRD) to later onset conditions described as autosomal recessive retinitis pigmentosa (arRP). 1-7 Recently, RPE65 has been established as the isomerase central to the retinoid visual cycle. 8 -10 This cycle 11 is crucial for supply of the chromophore 11-cis retinal for visual pigment regeneration. Animal models have contributed greatly to our understanding of the role of RPE65 in the visual cycle, regeneration, and retinal dystrophy. Rpe65 knockout mice display a biochemical phenotype consisting of extreme chromophore starvation (no rhodopsin) in the photoreceptors concurrent with overaccumulation of all-trans retinyl esters in the RPE 10 and are extremely insensitive to light. This insensitivity to light protects Rpe65 Ϫ/Ϫ mice from light damage, establishing rhodopsin as the mediator of light-induced retinal damage. 12 There is also a natural mutation in mouse Rpe65 called rd12. 14,15 The utility of gene therapy was established by preclinical trials in these dogs. 21 This level appears to be more than enough to maintain near-normal function. In contrast, human RPE65 EOSRD displays a wide spectrum of severity, age of onset, and progression not seen in animal models. In this article, we present the mild phenotypic consequences of a homozygous P25L missense mutation in a young patient and correlate these with the biochemical effect of this mutation on RPE65 activity. We show that even though the isomerase activity of the mutant RPE65 was quite impaired, the patient had near-normal visual acuity. However, rod function was extremely impaired. In addition, short-wavelength cones appeared more impaired than long-wavelength cones, consistent with findings in other patients with RPE65 mutations that blue color vision is much more and earlier impaired than is red vision, opposite to the usual case in cone dystrophies. These From th

An optimized derivative of an endogenous CXCR4 antagonist prevents atopic dermatitis and airway inflammation

Aberrant CXCR4/CXCL12 signaling is involved in many pathophysiological processes such as cancer and inflammatory diseases. A natural fragment of serum albumin, named EPI-X4, has previously been identified as endogenous peptide antagonist and inverse agonist of CXCR4 and is a promising compound for the development of improved analogues for the therapy of CXCR4-associated diseases. To generate optimized EPI-X4 derivatives we here performed molecular docking analysis to identify key interaction motifs of EPI-X4/CXCR4. Subsequent rational drug design allowed to increase the anti-CXCR4 activity of EPI-X4. The EPI-X4 derivative JM#21 bound CXCR4 and suppressed CXCR4-tropic HIV-1 infection more efficiently than the clinically approved small molecule CXCR4 antagonist AMD3100. EPI-X4 JM#21 did not exert toxic effects in zebrafish embryos and suppressed allergen-induced infiltration of eosinophils and other immune cells into the airways of animals in an asthma mouse model. Moreover, topical administration of the optimized EPI-X4 derivative efficiently prevented inflammation of the skin in a mouse model of atopic dermatitis. Thus, rationally designed EPI-X4 JM#21 is a novel potent antagonist of CXCR4 and the first CXCR4 inhibitor with therapeutic efficacy in atopic dermatitis. Further clinical development of this new class of CXCR4 antagonists for the therapy of atopic dermatitis, asthma and other CXCR4-associated diseases is highly warranted

Identification of a Phage Display-Derived Peptide Interacting with the N-Terminal Region of Factor VII Activating Protease (FSAP) Enables Characterization of Zymogen Activation

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Clinical characterization of 66 patients with congenital retinal disease due to the deep-intronic c.2991+1655A>G mutation in CEP290

PURPOSE. To describe the phenotypic spectrum of retinal disease caused by the c.2991+1655A>G mutation in CEP290 and to compare disease severity between homozygous and compound heterozygous patients. METHODS. Medical records were reviewed for best-corrected visual acuity (BCVA), age of onset, fundoscopy descriptions. Foveal outer nuclear layer (ONL) and ellipsoid zone (EZ) presence was assessed using spectral-domain optical coherence tomography (SD-OCT). Differences between compound heterozygous and homozygous patients were analyzed based on visual performance and visual development. RESULTS. A total of 66 patients were included. The majority of patients had either light perception or no light perception. In the remaining group of 14 patients, median BCVA was 20/195 Snellen (0.99 LogMAR; range 0.12–1.90) for the right eye, and 20/148 Snellen (0.87 LogMAR; range 0.22–1.90) for the left. Homozygous patients tended to be more likely to develop light perception compared to more severely affected compound heterozygous patients (P = 0.080) and are more likely to improve from no light perception to light perception (P = 0.022) before the age of 6 years. OCT data were available in 12 patients, 11 of whom had retained foveal ONL and EZ integrity up to 48 years (median 23 years) of age. CONCLUSIONS. Homozygous patients seem less severely affected compared to their compound-heterozygous peers. Improvement of visual function may occur in the early years of life, suggesting a time window for therapeutic intervention up to the approximate age of 17 years. This period may be extended by an intact foveal ONL and EZ on OCT