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1.
J Cell Sci ; 132(5)2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30665891

RESUMO

Bardet-Beidl syndrome (BBS) manifests from genetic mutations encoding for one or more BBS proteins. BBS4 loss impacts olfactory ciliation and odor detection, yet the cellular mechanisms remain unclear. Here, we report that Bbs4-/- mice exhibit shorter and fewer olfactory sensory neuron (OSN) cilia despite retaining odorant receptor localization. Within Bbs4-/- OSN cilia, we observed asynchronous rates of IFT-A/B particle movements, indicating miscoordination in IFT complex trafficking. Within the OSN dendritic knob, the basal bodies are dynamic, with incorporation of ectopically expressed centrin-2 and γ-tubulin occurring after nascent ciliogenesis. Importantly, BBS4 loss results in the reduction of basal body numbers separate from cilia loss. Adenoviral expression of BBS4 restored OSN cilia lengths and was sufficient to re-establish odor detection, but failed to rescue ciliary and basal body numbers. Our results yield a model for the plurality of BBS4 functions in OSNs that includes intraciliary and periciliary roles that can explain the loss of cilia and penetrance of ciliopathy phenotypes in olfactory neurons.

2.
PLoS Genet ; 13(10): e1007057, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29049287

RESUMO

Genetic mutations disrupting the structure and function of primary cilia cause various inherited retinal diseases in humans. Bardet-Biedl syndrome (BBS) is a genetically heterogeneous, pleiotropic ciliopathy characterized by retinal degeneration, obesity, postaxial polydactyly, intellectual disability, and genital and renal abnormalities. To gain insight into the mechanisms of retinal degeneration in BBS, we developed a congenital knockout mouse of Bbs8, as well as conditional mouse models in which function of the BBSome (a protein complex that mediates ciliary trafficking) can be temporally inactivated or restored. We demonstrate that BBS mutant mice have defects in retinal outer segment morphogenesis. We further demonstrate that removal of Bbs8 in adult mice affects photoreceptor function and disrupts the structural integrity of the outer segment. Notably, using a mouse model in which a gene trap inhibiting Bbs8 gene expression can be removed by an inducible FLP recombinase, we show that when BBS8 is restored in immature retinas with malformed outer segments, outer segment extension can resume normally and malformed outer segment discs are displaced distally by normal outer segment structures. Over time, the retinas of the rescued mice become morphologically and functionally normal, indicating that there is a window of plasticity when initial retinal outer segment morphogenesis defects can be ameliorated.


Assuntos
Morfogênese/fisiologia , Células Fotorreceptoras/metabolismo , Transporte Proteico/fisiologia , Animais , Síndrome de Bardet-Biedl/genética , Síndrome de Bardet-Biedl/metabolismo , Síndrome de Bardet-Biedl/patologia , Cílios/metabolismo , Camundongos , Camundongos Knockout , Modelos Animais , Morfogênese/genética , Mutação/genética , Transporte Proteico/genética , Retina/metabolismo , Retina/fisiologia
3.
Mol Ther ; 25(4): 904-916, 2017 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-28237838

RESUMO

Olfactory dysfunction is a pervasive but underappreciated health concern that affects personal safety and quality of life. Patients with olfactory dysfunctions have limited therapeutic options, particularly those involving congenital diseases. Bardet-Biedl syndrome (BBS) is one such disorder, where olfactory loss and other symptoms manifest from defective cilium morphology and/or function in various cell types/tissues. Olfactory sensory neurons (OSNs) of BBS mutant mice lack the capacity to build/maintain cilia, rendering the cells incapable of odor detection. Here we examined OSN cilium defects in Bbs1 mutant mice and assessed the utility of gene therapy to restore ciliation and function in young and adult mice. Bbs1 mutant mice possessed short residual OSN cilia in which BBSome protein trafficking and odorant detection were defective. Gene therapy with an adenovirus-delivered wild-type Bbs1 gene restored OSN ciliation, corrected BBSome cilium trafficking defects, and returned acute odor responses. Finally, using clinically approved AAV serotypes, we demonstrate, for the first time, the capacity of AAVs to restore ciliation and odor detection in OSNs of Bbs1 mutants. Together, our data demonstrate that OSN ciliogenesis can be promoted in differentiated cells of young and adult Bbs1 mutants and highlight the potential of gene therapy as a viable restorative treatment for congenital olfactory disorders.


Assuntos
Síndrome de Bardet-Biedl/genética , Síndrome de Bardet-Biedl/fisiopatologia , Terapia Genética , Neurônios Receptores Olfatórios/metabolismo , Alelos , Animais , Síndrome de Bardet-Biedl/terapia , Cílios/metabolismo , Cílios/patologia , Dependovirus/genética , Modelos Animais de Doenças , Expressão Ectópica do Gene , Expressão Gênica , Técnicas de Transferência de Genes , Vetores Genéticos/administração & dosagem , Vetores Genéticos/genética , Humanos , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Mutação , Percepção Olfatória/genética , Fenótipo , Transporte Proteico , Transdução Genética
5.
Nat Med ; 18(12): 1797-804, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23160237

RESUMO

Hydrocephalus is a common neurological disorder that leads to expansion of the cerebral ventricles and is associated with a high rate of morbidity and mortality. Most neonatal cases are of unknown etiology and are likely to have complex inheritance involving multiple genes and environmental factors. Identifying molecular mechanisms for neonatal hydrocephalus and developing noninvasive treatment modalities are high priorities. Here we use a hydrocephalic mouse model of the human ciliopathy Bardet-Biedl Syndrome (BBS) and identify a role for neural progenitors in the pathogenesis of neonatal hydrocephalus. We found that hydrocephalus in this mouse model is caused by aberrant platelet-derived growth factor receptor α (PDGFR-α) signaling, resulting in increased apoptosis and impaired proliferation of chondroitin sulfate proteoglycan 4 (also known as neuron-glial antigen 2 or NG2)(+)PDGFR-α(+) neural progenitors. Targeting this pathway with lithium treatment rescued NG2(+)PDGFR-α(+) progenitor cell proliferation in BBS mutant mice, reducing their ventricular volume. Our findings demonstrate that neural progenitors are crucial in the pathogenesis of neonatal hydrocephalus, and we identify new therapeutic targets for this common neurological disorder.


Assuntos
Antígenos/metabolismo , Apoptose/fisiologia , Síndrome de Bardet-Biedl/patologia , Hidrocefalia/etiologia , Células-Tronco Neurais/citologia , Proteoglicanas/metabolismo , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Transdução de Sinais/fisiologia , Animais , Western Blotting , Bromodesoxiuridina , Proliferação de Células/efeitos dos fármacos , Primers do DNA/genética , Feminino , Imuno-Histoquímica , Imunoprecipitação , Marcação In Situ das Extremidades Cortadas , Lítio/farmacologia , Imagem por Ressonância Magnética , Masculino , Camundongos , Camundongos Mutantes , Células-Tronco Neurais/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
6.
J Clin Invest ; 121(9): 3542-53, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21821918

RESUMO

Mutations in myocilin (MYOC) are the most common genetic cause of primary open angle glaucoma (POAG), but the mechanisms underlying MYOC-associated glaucoma are not fully understood. Here, we report the development of a transgenic mouse model of POAG caused by the Y437H MYOC mutation; the mice are referred to herein as Tg-MYOC(Y437H) mice. Analysis of adult Tg-MYOC(Y437H) mice, which we showed express human MYOC containing the Y437H mutation within relevant eye tissues, revealed that they display glaucoma phenotypes (i.e., elevated intraocular pressure [IOP], retinal ganglion cell death, and axonal degeneration) closely resembling those seen in patients with POAG caused by the Y437H MYOC mutation. Mutant myocilin was not secreted into the aqueous humor but accumulated in the ER of the trabecular meshwork (TM), thereby inducing ER stress in the TM of Tg-MYOC(Y437H) mice. Furthermore, chronic and persistent ER stress was found to be associated with TM cell death and elevation of IOP in Tg-MYOC(Y437H) mice. Reduction of ER stress with a chemical chaperone, phenylbutyric acid (PBA), prevented glaucoma phenotypes in Tg-MYOC(Y437H) mice by promoting the secretion of mutant myocilin in the aqueous humor and by decreasing intracellular accumulation of myocilin in the ER, thus preventing TM cell death. These results demonstrate that ER stress is linked to the pathogenesis of POAG and may be a target for treatment in human patients.


Assuntos
Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Glaucoma de Ângulo Aberto/tratamento farmacológico , Glaucoma de Ângulo Aberto/fisiopatologia , Fenilbutiratos/farmacologia , Fenilbutiratos/uso terapêutico , Estresse Fisiológico , Animais , Apoptose/fisiologia , Células Cultivadas , Proteínas do Citoesqueleto/genética , Retículo Endoplasmático/patologia , Proteínas do Olho/genética , Glaucoma de Ângulo Aberto/genética , Glaucoma de Ângulo Aberto/patologia , Glicoproteínas/genética , Humanos , Pressão Intraocular , Camundongos , Camundongos Transgênicos , Mutação , Fenótipo , Malha Trabecular/citologia , Malha Trabecular/metabolismo , Malha Trabecular/patologia , Transgenes , Resposta a Proteínas não Dobradas
7.
Am J Physiol Renal Physiol ; 300(2): F574-80, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21106857

RESUMO

Bardet-Biedl syndrome (BBS) is a rare hereditary autosomal recessive disease associated with several features including obesity, hypertension, and renal abnormalities. The underlying mechanisms of renal defects associated with BBS remain poorly defined. We examined the histological, molecular, and functional renal changes in BBS mouse models that have features of the human disorder. Interestingly, obese hypertensive Bbs4(-/-) mice exhibited inflammatory infiltration and renal cysts, whereas the obese normotensive Bbs2(-/-) mice had only minor inflammatory infiltration. Accordingly, the expression level of inducible nitric oxide synthase was elevated in the kidney of both BBS mice with a more marked increase in Bbs4(-/-) mice. In contrast, endothelial nitric oxide synthase expression was decreased in Bbs4(-/-), but not Bbs2(-/-), mice. Similarly, the expression levels of transient receptor potential vanilloid 1 and 4 channels as well as ß- and γ-subunits of epithelial Na channel were significantly reduced only in the kidney of Bbs4(-/-) mice. Metabolic studies revealed changes in urine output and urinary concentrations of creatinine, blood urea nitrogen, sodium, and potassium with a more pronounced effect in Bbs4(-/-) mice. Finally, we found that calorie restriction which prevented obesity in BBS mice reversed the morphological and molecular changes found in Bbs2(-/-) and Bbs4(-/-) mice, indicating the kidney abnormalities associated with BBS are obesity related. These findings extend our understanding of the function of BBS proteins and emphasize the importance of these proteins in renal physiology.


Assuntos
Síndrome de Bardet-Biedl/genética , Rim/anormalidades , Proteínas Associadas aos Microtúbulos/genética , Proteínas/genética , Animais , Nitrogênio da Ureia Sanguínea , Restrição Calórica , Creatinina/urina , Canais Epiteliais de Sódio/análise , Feminino , Hipertensão/genética , Masculino , Camundongos , Óxido Nítrico Sintase Tipo III/análise , Obesidade/genética , Oligúria/fisiopatologia , Potássio/urina , Sódio/urina , Canais de Cátion TRPV/análise
8.
Am J Hum Genet ; 86(5): 686-95, 2010 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-20398886

RESUMO

Retinitis pigmentosa is a genetically heterogeneous group of inherited ocular disorders characterized by progressive photoreceptor cell loss, night blindness, constriction of the visual field, and progressive visual disability. Homozygosity mapping and gene expression studies identified a 2 exon gene, C2ORF71. The encoded protein has no homologs and is highly expressed in the eye, where it is specifically expressed in photoreceptor cells. Two mutations were found in C2ORF71 in human RP patients: A nonsense mutation (p.W253X) in the first exon is likely to be a null allele; the second, a missense mutation (p.I201F) within a highly conserved region of the protein, leads to proteosomal degradation. Bioinformatic and functional studies identified and validated sites of lipid modification within the first three amino acids of the C2ORF71 protein. Using morpholino oligonucleotides to knockdown c2orf71 expression in zebrafish results in visual defects, confirming that C2ORF71 plays an important role in the development of normal vision. Finally, localization of C2ORF71 to primary cilia in cultured cells suggests that the protein is likely to localize to the connecting cilium or outer segment of photoreceptor cells.


Assuntos
Olho/metabolismo , Mutação , Células Fotorreceptoras de Vertebrados/metabolismo , Proteínas/genética , Retinite Pigmentosa/genética , Cegueira/genética , Cílios/genética , Cílios/metabolismo , Éxons , Proteínas do Olho/genética , Homozigoto , Humanos , Mutação de Sentido Incorreto , Retinite Pigmentosa/metabolismo
9.
PLoS Genet ; 6(3): e1000884, 2010 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-20333246

RESUMO

Bardet-Biedl Syndrome (BBS) is a heterogeneous syndromic form of retinal degeneration. We have identified a novel transcript of a known BBS gene, BBS3 (ARL6), which includes an additional exon. This transcript, BBS3L, is evolutionally conserved and is expressed predominantly in the eye, suggesting a specialized role in vision. Using antisense oligonucleotide knockdown in zebrafish, we previously demonstrated that bbs3 knockdown results in the cardinal features of BBS in zebrafish, including defects to the ciliated Kupffer's Vesicle and delayed retrograde melanosome transport. Unlike bbs3, knockdown of bbs3L does not result in Kupffer's Vesicle or melanosome transport defects, rather its knockdown leads to impaired visual function and mislocalization of the photopigment green cone opsin. Moreover, BBS3L RNA, but not BBS3 RNA, is sufficient to rescue both the vision defect as well as green opsin localization in the zebrafish retina. In order to demonstrate a role for Bbs3L function in the mammalian eye, we generated a Bbs3L-null mouse that presents with disruption of the normal photoreceptor architecture. Bbs3L-null mice lack key features of previously published Bbs-null mice, including obesity. These data demonstrate that the BBS3L transcript is required for proper retinal function and organization.


Assuntos
Fatores de Ribosilação do ADP/metabolismo , Visão Ocular , Proteínas de Peixe-Zebra/metabolismo , Fatores de Ribosilação do ADP/química , Fatores de Ribosilação do ADP/deficiência , Fatores de Ribosilação do ADP/genética , Sequência de Aminoácidos , Animais , Síndrome de Bardet-Biedl/complicações , Síndrome de Bardet-Biedl/genética , Síndrome de Bardet-Biedl/patologia , Síndrome de Bardet-Biedl/fisiopatologia , Anormalidades do Olho/complicações , Anormalidades do Olho/patologia , Anormalidades do Olho/fisiopatologia , Gânglios/efeitos dos fármacos , Gânglios/metabolismo , Gânglios/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Camundongos Mutantes , Dados de Sequência Molecular , Oligonucleotídeos Antissenso/farmacologia , Especificidade de Órgãos/efeitos dos fármacos , Fenótipo , Células Fotorreceptoras de Vertebrados/efeitos dos fármacos , Células Fotorreceptoras de Vertebrados/metabolismo , Células Fotorreceptoras de Vertebrados/patologia , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Transporte Proteico/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reflexo de Sobressalto/efeitos dos fármacos , Opsinas de Bastonetes/metabolismo , Visão Ocular/efeitos dos fármacos , Peixe-Zebra , Proteínas de Peixe-Zebra/química , Proteínas de Peixe-Zebra/genética
10.
Hum Mutat ; 31(4): 429-36, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20120035

RESUMO

Bardet-Biedl syndrome (BBS) is an autosomal recessive disease characterized by retinal dystrophy, polydactyly, obesity, learning disabilities, renal involvement, and male hypogenitalism. BBS is genetically heterogeneous with mutations of 14 genes, accounting for approximately 70% of cases. Triallelic inheritance has been suggested in about 5% of cases. Forty-nine unrelated BBS patients were screened for mutations by DHPLC analysis in BBS1, BBS2, BBS4, BBS6/MKKS, BBS10, and BBS12. The selected genes either account for more than 5% of the mutational load or are commonly reported in triallelic inheritance. Eight patients with only one or no BBS mutation were further investigated by single nucleotide polymorphism (SNP) analysis. In total, mutations were detected in 44 patients. Twenty percent had two mutations in BBS1, 18% in BBS2, 4% in BBS9, 43% in BBS10, and 2% in BBS12. Five patients were heterozygous for a sequence variation in BBS6/MKKS. We found eight patients with three sequence variations in two genes, which could be explained by triallelic inheritance, by the prevalence of heterozygous carriers or the third sequence variations representing rare polymorphisms. All changes found in a second BBS gene were amino acid substitutions. Genotype-phenotype correlations suggest a milder phenotype for BBS1 compared to BBS2 and BBS10, which we ascribe to the hypomorphic p.Met390Arg-mutation.


Assuntos
Síndrome de Bardet-Biedl/genética , Mutação/genética , Alelos , Sequência de Aminoácidos , Sequência de Bases , Sequência Conservada , Análise Mutacional de DNA , Dinamarca , Evolução Molecular , Feminino , Estudos de Associação Genética , Genótipo , Chaperoninas do Grupo II/química , Chaperoninas do Grupo II/genética , Humanos , Padrões de Herança/genética , Masculino , Dados de Sequência Molecular , Polimorfismo de Nucleotídeo Único/genética
11.
J Clin Invest ; 118(4): 1458-67, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18317593

RESUMO

Bardet-Biedl syndrome (BBS) is a heterogeneous genetic disorder characterized by many features, including obesity and cardiovascular disease. We previously developed knockout mouse models of 3 BBS genes: BBS2, BBS4, and BBS6. To dissect the mechanisms involved in the metabolic disorders associated with BBS, we assessed the development of obesity in these mouse models and found that BBS-null mice were hyperphagic, had low locomotor activity, and had elevated circulating levels of the hormone leptin. The effect of exogenous leptin on body weight and food intake was attenuated in BBS mice, which suggests that leptin resistance may contribute to hyperleptinemia. In other mouse models of obesity, leptin resistance may be selective rather than systemic; although mice became resistant to leptin's anorectic effects, the ability to increase renal sympathetic nerve activity (SNA) was preserved. Although all 3 of the BBS mouse models were similarly resistant to leptin, the sensitivity of renal SNA to leptin was maintained in Bbs4 -/- and Bbs6 -/- mice, but not in Bbs2 -/- mice. Consequently, Bbs4 -/- and Bbs6 -/- mice had higher baseline renal SNA and arterial pressure and a greater reduction in arterial pressure in response to ganglionic blockade. Furthermore, we found that BBS mice had a decreased hypothalamic expression of proopiomelanocortin, which suggests that BBS genes play an important role in maintaining leptin sensitivity in proopiomelanocortin neurons.


Assuntos
Síndrome de Bardet-Biedl/metabolismo , Hipertensão/metabolismo , Leptina/farmacologia , Proteínas Associadas aos Microtúbulos/metabolismo , Chaperonas Moleculares/metabolismo , Obesidade/metabolismo , Proteínas/metabolismo , Animais , Síndrome de Bardet-Biedl/genética , Síndrome de Bardet-Biedl/patologia , Barreira Hematoencefálica/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Modelos Animais de Doenças , Eletrocardiografia , Regulação da Expressão Gênica/efeitos dos fármacos , Chaperoninas do Grupo II , Hipertensão/genética , Imagem por Ressonância Magnética , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/deficiência , Proteínas Associadas aos Microtúbulos/genética , Chaperonas Moleculares/genética , Obesidade/genética , Tamanho do Órgão , Proteínas/genética
13.
Proc Natl Acad Sci U S A ; 104(49): 19422-7, 2007 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-18032602

RESUMO

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous disorder that results in retinal degeneration, obesity, cognitive impairment, polydactyly, renal abnormalities, and hypogenitalism. Of the 12 known BBS genes, BBS1 is the most commonly mutated, and a single missense mutation (M390R) accounts for approximately 80% of BBS1 cases. To gain insight into the function of BBS1, we generated a Bbs1(M390R/M390R) knockin mouse model. Mice homozygous for the M390R mutation recapitulated aspects of the human phenotype, including retinal degeneration, male infertility, and obesity. The obese mutant mice were hyperphagic and hyperleptinemic and exhibited reduced locomotor activity but no elevation in mean arterial blood pressure. Morphological evaluation of Bbs1 mutant brain neuroanatomy revealed ventriculomegaly of the lateral and third ventricles, thinning of the cerebral cortex, and reduced volume of the corpus striatum and hippocampus. Similar abnormalities were also observed in the brains of Bbs2(-/-), Bbs4(-/-), and Bbs6(-/-) mice, establishing these neuroanatomical defects as a previously undescribed BBS mouse model phenotype. Ultrastructural examination of the ependymal cell cilia that line the enlarged third ventricle of the Bbs1 mutant brains showed that, whereas the 9 + 2 arrangement of axonemal microtubules was intact, elongated cilia and cilia with abnormally swollen distal ends were present. Together with data from transmission electron microscopy analysis of photoreceptor cell connecting cilia, the Bbs1 M390R mutation does not affect axonemal structure, but it may play a role in the regulation of cilia assembly and/or function.


Assuntos
Síndrome de Bardet-Biedl/genética , Síndrome de Bardet-Biedl/patologia , Modelos Animais de Doenças , Camundongos/genética , Proteínas Associadas aos Microtúbulos/genética , Animais , Ventrículos Cerebrais/patologia , Cílios/ultraestrutura , Masculino , Mutação , Obesidade/genética , Doenças Retinianas/genética , Cauda do Espermatozoide/patologia
14.
Invest Ophthalmol Vis Sci ; 48(7): 3329-40, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17591906

RESUMO

PURPOSE: To identify and characterize gene expression changes associated with photoreceptor cell loss in a Bbs4-knockout mouse model of retinal degeneration. METHODS: Differential gene expression in the eyes of 5-month-old Bbs4(-/-) mice undergoing retinal degeneration were analyzed using gene microarrays (Affymetrix, Santa Clara, CA). Elevated ocular transcripts were confirmed by Northern blotting of RNA from Bbs4(-/-) and three additional mouse models of Bardet-Biedl Syndrome (BBS). TUNEL assays and transmission electron microscopy were used to study cell death and photoreceptor morphology in these mice. RESULTS: Three hundred fifty-four probes were differentially expressed in Bbs4(-/-) eyes compared with controls using a twofold cutoff. Numerous vision-related transcripts decreased because of photoreceptor cell loss. Increased expression of the stress response genes Edn2, Lcn2, Serpina3n, and Socs3 was noted at 5 months of age and as early as postnatal week 4 in the eyes of four BBS mouse model strains. A burst of apoptotic activity in the photoreceptor outer nuclear layer at postnatal week 2 and highly disorganized outer segments by postnatal weeks 4 to 6 was observed in all four strains. CONCLUSIONS: The specific loss of photoreceptors in Bbs4(-)(/)(-) mice allows us to identify a set of genes that are preferentially expressed in photoreceptors compared with other cell types found in the eye and is a valuable resource in the continuing search for genes involved in retinal disease. The molecular and morphologic changes observed in young BBS animal model eyes implies that BBS proteins play a critical, early role in establishing the correct structure and function of photoreceptors.


Assuntos
Proteínas da Fase Aguda/genética , Síndrome de Bardet-Biedl/genética , Regulação da Expressão Gênica , Proteínas Associadas aos Microtúbulos/genética , Células Fotorreceptoras de Vertebrados/metabolismo , Degeneração Retiniana/genética , Animais , Apoptose , Síndrome de Bardet-Biedl/metabolismo , Síndrome de Bardet-Biedl/patologia , Northern Blotting , Endotelina-2/genética , Perfilação da Expressão Gênica , Marcação In Situ das Extremidades Cortadas , Lipocalina-2 , Lipocalinas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Oncogênicas/genética , Células Fotorreceptoras de Vertebrados/patologia , Degeneração Retiniana/metabolismo , Degeneração Retiniana/patologia , Serpinas/genética , Proteína 3 Supressora da Sinalização de Citocinas , Proteínas Supressoras da Sinalização de Citocina/genética
15.
Eur J Med Genet ; 50(2): 120-7, 2007 Mar-Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17157569

RESUMO

We report a 22-year-old female with a variant of the Axenfeld-Rieger Syndrome (ARS) and discuss its relation with the subtelomeric 6p deletion. An ARS variant has been described in two familial cases of Axenfeld-Rieger Anomaly (ARA) featuring specific extra ocular manifestations-hypertelorism, midface hypoplasia, mild sensorial deafness, hydrocephaly, psychomotor delay and flattened femoral epiphyses. We proposed that this set of characteristics represents a separate syndrome within the ARS. On the other hand, there have been reported four cases with cryptic de novo pure 6pter microdeletions detected by specific subtelomeric probes in patients with ARS characteristics. We describe a 6pter deletion detected by SNP genotyping and confirmed by FISH and MLPA involving the FOXC1 gene in a patient with ocular and systemic findings that fit perfectly with the variant mentioned above. We conclude that the ARS variant belongs to the ARS phenotypic spectrum, which includes flattened femoral epiphyses as a feature.


Assuntos
Anormalidades Múltiplas/genética , Deleção Cromossômica , Cromossomos Humanos Par 6 , Anormalidades do Olho/genética , Variação Genética , Anormalidades Múltiplas/diagnóstico por imagem , Adulto , Mapeamento Cromossômico , Sondas de DNA , Feminino , Fatores de Transcrição Forkhead/genética , Genótipo , Quadril/diagnóstico por imagem , Humanos , Hipertelorismo/genética , Hibridização in Situ Fluorescente , Deficiência Intelectual/genética , Cariotipagem , Polimorfismo de Nucleotídeo Único , Radiografia , Síndrome
16.
Proc Natl Acad Sci U S A ; 103(16): 6287-92, 2006 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-16606853

RESUMO

The identification of mutations in genes that cause human diseases has largely been accomplished through the use of positional cloning, which relies on linkage mapping. In studies of rare diseases, the resolution of linkage mapping is limited by the number of available meioses and informative marker density. One recent advance is the development of high-density SNP microarrays for genotyping. The SNP arrays overcome low marker informativity by using a large number of markers to achieve greater coverage at finer resolution. We used SNP microarray genotyping for homozygosity mapping in a small consanguineous Israeli Bedouin family with autosomal recessive Bardet-Biedl syndrome (BBS; obesity, pigmentary retinopathy, polydactyly, hypogonadism, renal and cardiac abnormalities, and cognitive impairment) in which previous linkage studies using short tandem repeat polymorphisms failed to identify a disease locus. SNP genotyping revealed a homozygous candidate region. Mutation analysis in the region of homozygosity identified a conserved homozygous missense mutation in the TRIM32 gene, a gene coding for an E3 ubiquitin ligase. Functional analysis of this gene in zebrafish and expression correlation analyses among other BBS genes in an expression quantitative trait loci data set demonstrate that TRIM32 is a BBS gene. This study shows the value of high-density SNP genotyping for homozygosity mapping and the use of expression correlation data for evaluation of candidate genes and identifies the proteasome degradation pathway as a pathway involved in BBS.


Assuntos
Síndrome de Bardet-Biedl/genética , Polimorfismo de Nucleotídeo Único , Fatores de Transcrição/genética , Ubiquitina-Proteína Ligases/genética , Animais , Mapeamento Cromossômico , Análise Mutacional de DNA , Genoma Humano , Homozigoto , Humanos , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Fatores de Transcrição/metabolismo , Proteínas com Motivo Tripartido , Peixe-Zebra , Proteínas de Peixe-Zebra/genética
17.
Am J Hum Genet ; 77(6): 1021-33, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16380913

RESUMO

Bardet-Biedl syndrome (BBS) is an autosomal recessive, genetically heterogeneous, pleiotropic human disorder characterized by obesity, retinopathy, polydactyly, renal and cardiac malformations, learning disabilities, and hypogenitalism. Eight BBS genes representing all known mapped loci have been identified. Mutation analysis of the known BBS genes in BBS patients indicate that additional BBS genes exist and/or that unidentified mutations exist in the known genes. To identify new BBS genes, we performed homozygosity mapping of small, consanguineous BBS pedigrees, using moderately dense SNP arrays. A bioinformatics approach combining comparative genomic analysis and gene expression studies of a BBS-knockout mouse model was used to prioritize BBS candidate genes within the newly identified loci for mutation screening. By use of this strategy, parathyroid hormone-responsive gene B1 (B1) was found to be a novel BBS gene (BBS9), supported by the identification of homozygous mutations in BBS patients. The identification of BBS9 illustrates the power of using a combination of comparative genomic analysis, gene expression studies, and homozygosity mapping with SNP arrays in small, consanguineous families for the identification of rare autosomal recessive disorders. We also demonstrate that small, consanguineous families are useful in identifying intragenic deletions. This type of mutation is likely to be underreported because of the difficulty of deletion detection in the heterozygous state by the mutation screening methods that are used in many studies.


Assuntos
Síndrome de Bardet-Biedl/genética , Expressão Gênica , Genes Recessivos , Genômica , Proteínas de Neoplasias/genética , Alelos , Elementos Alu , Sequência de Bases , Mapeamento Cromossômico , Biologia Computacional , Consanguinidade , Análise Mutacional de DNA , Feminino , Deleção de Genes , Homozigoto , Humanos , Masculino , Dados de Sequência Molecular , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Linhagem , Polimorfismo de Nucleotídeo Único
18.
Hum Mol Genet ; 14(9): 1109-18, 2005 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-15772095

RESUMO

McKusick-Kaufman syndrome (MKS) is an autosomal recessive disorder characterized by post-axial polydactyly, congenital heart defects and hydrometrocolpos, a congenital structural abnormality of female genitalia. Mutations in the MKKS gene have also been shown to cause some cases of Bardet-Biedl syndrome (BBS) which is characterized by obesity, pigmentary retinopathy, polydactyly, renal abnormalities and hypogenitalism with secondary features of hypertension and diabetes. Although there is overlap in clinical features between MKS and BBS, MKS patients are not obese and do not develop retinopathy or have learning disabilities. To further explore the pathophysiology of BBS and the related disorder MKS, we have developed an Mkks(-/-) mouse model. This model shows that the absence of Mkks leads to retinal degeneration through apoptosis, failure of spermatozoa flagella formation, elevated blood pressure and obesity. The obesity is associated with hyperphagia and decreased activity. In addition, neurological screening reveals deficits in olfaction and social dominance. The mice do not have polydactyly or vaginal abnormalities. The phenotype of the Mkks(-/-) mice closely resembles the phenotype of other mouse models of BBS (Bbs2(-/-) and Bbs4(-/-)). These observations suggest that the complete absence of MKKS leads to BBS while the MKS phenotype is likely to be due to specific mutations.


Assuntos
Anormalidades Múltiplas/genética , Síndrome de Bardet-Biedl/genética , Fenótipo , Proteínas/genética , Alelos , Animais , Síndrome de Bardet-Biedl/metabolismo , Síndrome de Bardet-Biedl/patologia , Síndrome de Bardet-Biedl/fisiopatologia , Pressão Sanguínea/genética , Modelos Animais de Doenças , Genes Recessivos , Humanos , Leptina/sangue , Leptina/genética , Masculino , Camundongos , Camundongos Knockout , Modelos Genéticos , Obesidade/genética , Obesidade/metabolismo , Degeneração Retiniana/genética , Degeneração Retiniana/patologia , Predomínio Social , Cauda do Espermatozoide/metabolismo , Cauda do Espermatozoide/patologia , Síndrome
19.
Proc Natl Acad Sci U S A ; 101(47): 16588-93, 2004 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-15539463

RESUMO

Bardet-Biedl syndrome (BBS) is a heterogeneous, pleiotropic human disorder characterized by obesity, retinopathy, polydactyly, renal and cardiac malformations, learning disabilities, hypogenitalism, and an increased incidence of diabetes and hypertension. No information is available regarding the specific function of BBS2. We show that mice lacking Bbs2 gene expression have major components of the human phenotype, including obesity and retinopathy. In addition, these mice have phenotypes associated with cilia dysfunction, including retinopathy, renal cysts, male infertility, and a deficit in olfaction. With the exception of male infertility, these phenotypes are not caused by a complete absence of cilia. We demonstrate that BBS2 retinopathy involves normal retina development followed by apoptotic death of photoreceptors, the primary ciliated cells of the retina. Photoreceptor cell death is preceded by mislocalization of rhodopsin, indicating a defect in transport. We also demonstrate that Bbs2(-/-) mice and a second BBS mouse model, Bbs4(-/-), have a defect in social function. The evaluation of Bbs2(-/-) mice indicates additional phenotypes that should be evaluated in human patients, including deficits in social interaction and infertility.


Assuntos
Síndrome de Bardet-Biedl/genética , Síndrome de Bardet-Biedl/metabolismo , Rodopsina/metabolismo , Animais , Apoptose , Síndrome de Bardet-Biedl/patologia , Cílios/patologia , Modelos Animais de Doenças , Marcação de Genes , Humanos , Doenças Renais Císticas/genética , Doenças Renais Císticas/patologia , Masculino , Camundongos , Camundongos Knockout , Obesidade/genética , Obesidade/metabolismo , Fenótipo , Células Fotorreceptoras de Vertebrados/patologia , Retinite Pigmentosa/genética , Retinite Pigmentosa/metabolismo , Retinite Pigmentosa/patologia , Transtornos das Sensações/genética , Transtornos das Sensações/fisiopatologia , Predomínio Social , Espermatogênese/genética , Espermatogênese/fisiologia
20.
Am J Ophthalmol ; 135(3): 368-75, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12614756

RESUMO

PURPOSE: Mutations of the forkhead transcription factor gene FOXC1 result in anterior segment anomalies. No description of the spectrum of defects resulting from a single point mutation of this gene exists in the ophthalmology literature. We have screened all available patients with Axenfeld-Rieger genes (PITX2 and FOXC1). In this report, we clinically characterize the spectrum of ocular and systemic manifestations in one family resulting from a previously reported point mutation (Phe112Ser) in FOXC1. DESIGN: Observational case series. METHODS: Ten members of a multigenerational family were examined for signs of glaucoma, anterior segment abnormalities, and systemic features of Axenfeld-Rieger syndrome. The examinations were performed in an ophthalmology examination room or in the patients' homes. Blood was obtained from 10 members and screened for mutations in FOXC1 using direct DNA sequencing. RESULTS: A single mutation causing a T to C change in codon 112 (Phe112Ser) of FOXC1 was present in six members of the family. Five of these six patients were examined and all demonstrated anterior segment anomalies. One patient had Axenfeld anomaly, one had Rieger syndrome, and one had both Axenfeld anomaly and Peters anomaly. Additionally, some members demonstrated cardiac abnormalities, which may be secondary to their FOXC1 mutation. CONCLUSIONS: A wide spectrum of clinical phenotypes can result from a single point mutation of FOXC1. This report confirms that Rieger syndrome (with dental and facial abnormalities) can be caused by a mutation in FOXC1. It is also the first report of Peters anomaly being caused by a FOXC1 mutation.


Assuntos
Anormalidades Múltiplas/genética , Segmento Anterior do Olho/anormalidades , Proteínas de Ligação a DNA , Anormalidades do Olho/genética , Iris/anormalidades , Mutação Puntual , Fatores de Transcrição/genética , Adolescente , Adulto , Idoso , Criança , Opacidade da Córnea/genética , Análise Mutacional de DNA , Ossos Faciais/anormalidades , Feminino , Fatores de Transcrição Forkhead , Glaucoma/genética , Humanos , Masculino , Linhagem , Síndrome , Anormalidades Dentárias/genética
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