Centrosomal-ciliary gene CEP290/NPHP6 mutations result in blindness with unexpected sparing of photoreceptors and visual brain: implications for therapy of Leber congenital amaurosis

Mutations in the centrosomal-ciliary gene CEP290/NPHP6 are associated with Joubert syndrome and are the most common cause of the childhood recessive blindness known as Leber congenital amaurosis (LCA). An in-frame deletion in Cep290 shows rapid degeneration in the rod-rich mouse retina. To explore the mechanisms of the human retinal disease, we studied CEP290-LCA in patients of different ages (7-48 years) and compared results to Cep290-mutant mice. Unexpectedly, blind CEP290-mutant human retinas retained photoreceptor and inner laminar architecture in the cone-rich central retina, independent of severity of visual loss. Surrounding the cone-rich island was photoreceptor loss and distorted retina, suggesting neural-glial remodeling. The mutant mouse retina at 4-6 weeks of age showed similar features of retinal remodeling, with altered neural and synaptic laminae and Muller glial activation. The visual brain pathways in CEP290-LCA were anatomically intact. Our findings of preserved foveal cones and visual brain anatomy in LCA with CEP290 mutations, despite severe blindness and rapid rod cell death, suggest an opportunity for visual restoration of central vision in this common form of inherited blindness.     

Mfrp,a gene encoding a frizzled related protein,is mutated in the mouse retinal degeneration 6

The autosomal recessive mouse mutation retinal degeneration 6 (rd6) causes small, white retinal spots and progressive photoreceptor degeneration similar to that observed in human flecked retinal diseases. Using a positional cloning approach, we determined that rd6 mice carry a splice donor mutation in the mouse homolog of the human membrane-type frizzled-related protein (Mfrp) gene that results in the skipping of exon 4. We found that mRNA of Mfrp is predominantly expressed in the eye, and at a lower level in the brain. To determine where in the eye Mfrp is expressed, in situ hybridization was done and showed that Mfrp is expressed specifically in the retinal pigment epithelium (RPE) and ciliary epithelium of the eye. The deduced amino acid sequence of MFRP contains a region with similarities to the cysteine-rich domain (CRD) of frizzled, a gene originally found in Drosophila that controls tissue polarity. The CRD is essential for Wnt binding and signaling. Wnt signaling has been shown to be involved in the control of gene expression, cell adhesion, planar polarity, proliferation and apoptosis. We also observed the localization of Wnt family proteins in the apical membrane of the RPE. Our results provide genetic evidence for an involvement of the Mfrp gene expressed by RPE in the degeneration of photoreceptors.     

Mutations in a novel cilia-centrosome protein cause a cystic kidney disease associated with retinal degeneration

Candidate exome capture identifies mutation of SDCCAG8 as the cause of a retinal‐renal ciliopathy Otto et al. (2010) Nature Genetics 42(10):840–50     

A novel mutation in NFKBIA/IKBA results in a degradation-resistant N-truncated protein and is associated with ectodermal dysplasia with immunodeficiency

Alterations in nuclear factor kappa B (NF-kappaB) essential modulator (NEMO; HUGO-approved symbol IKBKG) underlie most cases of ectodermal dysplasia with immune deficiency (EDI), a human disorder characterized by anhidrosis with diminished immunity. EDI has also been associated with a single heterozygous mutation at position Ser32 of the NF-kappaB inhibitor IkappaBalpha, one of two phosphorylation sites that are essential for targeting IkappaBalpha for proteasomal degradation and hence for activation of NF-kappaB. We report a novel heterozygous nonsense mutation in the IKBA (HUGO-approved symbol, NFKBIA) gene of a 1-year-old male child with EDI that introduces a premature termination codon at position Glu14. An in-frame methionine downstream of the nonsense mutation allows for reinitiation of translation. The resulting N-terminally truncated protein lacks both serine phosphorylation sites and inhibits NF-kappaB signaling by functioning as a dominant negative on NF-kappaB activity in lymphocytes and monocytes. These findings support the scanning model for translation initiation in eukaryotes and confirm the critical role of the NF-kappaB in the human immune response.     

Immune response induced by three Mycobacterium bovis BCG substrains with diverse regions of deletion in a C57BL/6 mouse model

This study was performed to examine the adaptive immune response generated by three Mycobacterium bovis bacillus Calmette-Guérin (BCG) substrains to determine if the number of genomic regions of deletion played a significant role in determining the magnitude of the immune response or affected their ability to reduce the bacterial burden following low-dose aerosol challenge with a virulent M. tuberculosis strain. BCG Connaught, Pasteur, and Sweden were chosen as representative substrains, as they possessed many, intermediate, and few regions of deletion, respectively, as a result of changes in the genome in various regions. Mice were vaccinated subcutaneously and were then examined at 14, 21, and 42 days postvaccination. BCG was observed in the spleen, lung, and lymph nodes. BCG Connaught induced a greater pulmonary T-cell response than the other two substrains at day 14 postvaccination, although by 42 days postvaccination activated T-cell levels dropped to the levels observed in control mice for all three substrains. Among the three substrains, BCG Connaught induced significantly greater levels of interleukin-12 in bone marrow-derived macrophage cultures. Mice challenged at days 14, 21, and 42 postvaccination displayed an equal capacity to reduce the bacterial burden in the lungs and spleen. The data provide evidence that although the BCG substrains generated qualitatively and quantitatively different immune responses, they induced similar reductions in the bacterial burden against challenge with a virulent M. tuberculosis strain in the mouse model of tuberculosis. The data raise questions about the assessment of vaccine immune responses and the relationship to a vaccine's ability to reduce the bacterial burden.     

Mutation analysis of the BRCA1 and BRCA2 genes results in the identification of novel and recurrent mutations in 6/16 flemish families with breast and/or ovarian cancer but not in 12 sporadic patients with early-onset disease. Mutations in brief no. 224. Online

Since the identification of the BRCA1 and BRCA2 genes (MIM#s 113705 and 600185), more than hundred different mutations throughout both genes have been reported. Recurrent mutations are rare and mainly due to founder effects. We analyzed 12 sporadic female patients with breast cancer before age 35, as well as 16 unrelated families, presenting with either (i) at least 3 first degree relatives with breast and/or ovarian cancer diagnosed at any age, or (ii) at least 2 first and/or second degree relatives with breast and/or ovarian cancer before age 45 years. We performed a protein truncation test for BRCA1 exon 11 and BRCA2 exons 10 and 11 and heteroduplex analysis for all the remaining exons of BRCA1 and 2. Presence of genomic deletions encompassing exons 13 or 22 of BRCA1, known to be Dutch founder mutations, was investigated by PCR. In 6/16 (37.5%) unrelated families the causal mutation in either the BRCA1 or BRCA2 gene was identified. Four different mutations were found in the BRCA1 gene: IVS5+3A>G (intron 5), 1191delC (exon 11), R1443X (exon 13), IVS22+5G>A (intron 22) and two in the BRCA2 gene: 6503delTT (exon 11), 6831delTG (exon 11). 1191delC (BRCA1) and 6831delTG (BRCA2) are novel mutations. IVS5+3A>G in exon 5 of BRCA1 published by Peelen et al. (1997) as a novel Belgian mutation, was identified in one additional family, not fulfilling our inclusion criteria. In the group of 12 sporadic female patients no mutations were found.     

Recombinant group B streptococcus Beta C protein and a variant with the deletion of its immunoglobulin A-binding site are protective mouse maternal vaccines and effective carriers in conjugate vaccines

Immunogenic vaccines against group B Streptococcus (GBS) have been created by coupling the GBS capsular polysaccharides (CPS) to carrier proteins. The GBS beta C protein (BCP) serves as an effective carrier while inducing protective immunity against BCP-expressing strains. BCP also binds human immunoglobulin A (IgA), a characteristic that may be undesirable for use in humans. Here, we examined the immunogenicity and protective efficacy of a recombinant GBS BCP (rBCP), an rBCP modified to eliminate its IgA-binding site (rBCP(DeltaIgA)), and their corresponding GBS serotype III CPS conjugates (III-rBCP and III-rBCP(DeltaIgA)). Deletion of the IgA-binding site or conjugation to CPS did not alter antigenic BCP epitopes. Recombinant proteins and conjugates elicited specific, high-titered IgG in mice. Antisera to rBCP, rBCP(DeltaIgA), III-rBCP, and III-rBCP(DeltaIgA) opsonized GBS strains A909 (Ia/BCP(+)) and H36B (Ib/BCP(+)) for killing by HL-60 cells; antiserum to III-rBCP and III-rBCP(DeltaIgA) also opsonized strain M781 (III/BCP(-)). Vaccination of female mice with either rBCP or rBCP(DeltaIgA) protected approximately 40% of their pups challenged with GBS strain A909. Pups born to III-rBCP- or III-rBCP(DeltaIgA)-vaccinated dams survived at rates of 56% and 66%, respectively. Over 90% of pups born to dams that received the type III CPS conjugates survived challenge with GBS strain M781. In summary, rBCP and rBCP(DeltaIgA) proteins and the conjugates containing them were immunogenic in mice, inducing both CPS- and protein-specific functional IgG. These results suggest that the rBCP(DeltaIgA) could be used as a carrier to augment the immunogenicity of the CPS while expanding coverage to GBS strains bearing BCP.     

Simultaneous immunisation with a Wilms' tumour 1 epitope and its ubiquitin fusions results in enhanced cell mediated immunity and tumour rejection in C57BL/6 mice

Protein fusion to ubiquitin results in its targeting to proteasome and processing through MHC class I pathway. We used this approach to induce cytotoxic T lymphocyte (CTL) response against a MHC class I epitope. Therefore, two known proteasome targeting systems, "ubiquitin fusion degradation" (UFD) and "N-end rule", were used to immunise C57BL/6 mice. Two plasmids encoding an epitope from Wilms' Tumour 1 (WT1-126), fused N-terminally to ubiquitin, were constructed. They were designated as "pUbVVPT" and "pUbGRPT", targeting the fused epitope to UFD and N-end pathways, respectively. A plasmid encoding WT1-126 without ubiquitin fusion (pPT) was also constructed as control. Three mice groups were immunised using these constructs (UGR, UVV and PT groups). Two other groups received mixed immunisations of pUbVVPT or pUbGRPT plus pPT plasmids (UVV+PT and UGR+PT). All mice received a WT1-126 peptide booster. Lymphoproliferative responses following stimulation with WT1-126 were observed in all immunisation groups, with mice receiving the mixture of plasmids eliciting the highest proliferation (UVV+PT>UGR+PT>PT). Moreover, In vivo cytotoxicity assay results revealed highest specific lysis of target cells in UVV+PT group. Tumour growth was decreased in all immunised groups, and was completely abrogated in UGR+PT group. In addition, T(H)1 type cytokines patterns were detected from all immunised groups and WT1-126-specific IFNγ producing lymphocytes were developed in them. These results suggest that the delivery of ubiquitin-fused epitopes along with epitopes alone can be used to optimise the effect of DNA vaccines on the induction of anti-tumour immunity.