RESUMEN
BACKGROUND: Consanguineous couples have an increased risk of severe diseases in offspring due to autosomal recessive disorders. Exome sequencing (ES) offers the possibility of extensive preconception carrier screening (PCS) in consanguineous couples who may be at risk of rare genetic disorders. METHODS: We retrospectively analysed ES data from 65 probands affected with rare genetic disorders born from consanguineous couples. We explored diagnostic yield and carrier status for recessive disorders. RESULTS: The overall diagnostic yield in a singleton approach was 53.8%, mostly recessive variants. In a hypothetical exome-based PCS, only 11.7% of these causative rare variants would have been missed in the filtering process. Carrier screening for recessive conditions allowed the identification of at least one additional pathogenic or likely pathogenic variant in 85.7% of the probands, being the majority with a gene carrier frequency <1 in 200. In addition, considering only clinically actionable conditions, we estimated that 12.3% of our close consanguineous couples may be at risk for an additional recessive disease. CONCLUSIONS: Our results demonstrate that ES outperforms panel-based screening in a PCS context in consanguineous couples and could potentially increase their reproductive autonomy and facilitate informed decision-making.
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Enfermedades Raras , Humanos , Consanguinidad , Secuenciación del Exoma , Estudios Retrospectivos , Genes Recesivos , Frecuencia de los Genes , Enfermedades Raras/genética , Tamización de Portadores GenéticosRESUMEN
BACKGROUND/OBJECTIVES: Exome sequencing may identify pathogenic variants unrelated with the purpose of the analysis. We investigated the frequency of secondary and incidental findings (SF/IF) in cancer susceptibility genes (CSG), their clinical actionability and the psychological impact in individuals with an SF/IF (cases) compared with individuals tested due to their cancer history (controls). METHODS: This study analysed 533 exomes ordered for non-cancer conditions. Medical records were reviewed for clinical actionability of SF/IF. Psychological impact was analysed using the Multidimensional Impact of Cancer Risk Assessment (MICRA) scale and compared between cases and controls with a propensity score weighting method. RESULTS: The frequency of SF/IF in CSG was 2.1% (95% CI 1.1% to 3.8%): three BRCA2, three PMS2, two SDHB, and one each in BRCA1, MLH1 and RAD51C. Among the relatives, 18 were carriers. Twenty enrolled for surveillance, and a neoplasm was diagnosed in 20%: three paragangliomas and one breast cancer. Cases presented higher MICRA mean scores than controls (21.3 vs 16.2 in MICRA total score, 6.3 vs 4.2 in the distress subscale, and 8.3 vs 6.6 in the uncertainty subscale; all p<0.001). CONCLUSION: SF/IF in CSG were identified in 2.1% of patients. Despite a numerically higher psychological impact, the identification of SF/IF allowed early detection and cancer prevention in families without cancer history.
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Neoplasias de la Mama , Predisposición Genética a la Enfermedad , Humanos , Femenino , Secuenciación del Exoma , Hallazgos Incidentales , Neoplasias de la Mama/genética , Genes BRCA2RESUMEN
Thyroid dyshormonogenesis (THD) is a heterogeneous group of genetic diseases caused by the total or partial defect in the synthesis or secretion of thyroid hormones. Genetic variants in DUOX2 can cause partial to total iodination organification defects and clinical heterogeneity, from transient to permanent congenital hypothyroidism. The aim of this study was to undertake a molecular characterization and genotype-phenotype correlation in patients with THD and candidate variants in DUOX2. A total of 31 (19.38%) patients from the Catalan Neonatal Screening Program presented with variants in DUOX2 that could explain their phenotype. Fifteen (48.39%) patients were compound heterozygous, 10 (32.26%) heterozygous, and 4 (12.90%) homozygous. In addition, 8 (26.67%) of these patients presented variants in other genes. A total of 35 variants were described, 10 (28.57%) of these variants have not been previously reported in literature. The most frequent variant in our cohort was c.2895_2898del/p.(Phe966SerfsTer29), classified as pathogenic according to reported functional studies. The final diagnosis of this cohort was permanent THD in 21 patients and transient THD in 10, according to reevaluation and/or need for treatment with levothyroxine. A clear genotype-phenotype correlation could not be identified; therefore, functional studies are necessary to confirm the pathogenicity of the variants.
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Oxidasas Duales , Estudios de Asociación Genética , Humanos , Oxidasas Duales/genética , Oxidasas Duales/metabolismo , Femenino , Masculino , Recién Nacido , Disgenesias Tiroideas/genética , Disgenesias Tiroideas/patología , Fenotipo , Mutación , Genotipo , Hipotiroidismo Congénito/genética , Tamizaje Neonatal , TiroxinaRESUMEN
RRM2B encodes the p53-inducible small subunit (p53R2) of ribonucleotide reductase, a key protein for mitochondrial DNA (mtDNA) synthesis. Pathogenic variants in this gene result in familial mitochondrial disease in adults and children, secondary to a maintenance disorder of mtDNA. This study describes two patients, mother and son, with early-onset chronic progressive external ophthalmoplegia (PEO). Skeletal muscle biopsy from the latter was examined: cytochrome c oxidase (COX)-negative fibres were shown, and molecular studies revealed multiple mtDNA deletions. A next-generation sequencing gene panel for nuclear-encoded mitochondrial maintenance genes identified two unreported heterozygous missense variants (c.514 G > A and c.682 G > A) in the clinically affected son. The clinically affected mother harboured the first variant in homozygous state, and the clinically unaffected father harboured the remaining variant in heterozygous state. In silico analyses predicted both variants as deleterious. Cell culture studies revealed that patients' skin fibroblasts, but not fibroblasts from healthy controls, responded to nucleoside supplementation with enhanced mtDNA repopulation, thus suggesting an in vitro functional difference in patients' cells. Our results support the pathogenicity of two novel RRM2B variants found in two patients with autosomal recessive PEO with multiple mtDNA deletions inherited with a pseudodominant pattern.
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Oftalmoplejía Externa Progresiva Crónica , Oftalmoplejía , Ribonucleótido Reductasas , Adulto , Niño , Humanos , Oftalmoplejía Externa Progresiva Crónica/genética , Oftalmoplejía Externa Progresiva Crónica/patología , Patrón de Herencia , ADN Mitocondrial/genética , Ribonucleótido Reductasas/genética , Proteínas de Ciclo Celular/genéticaRESUMEN
Chronic progressive external ophthalmoplegia (CPEO) plus syndrome due to pathogenic biallelic variants in TOP3A gene has been described in only one single patient. We report two adult siblings with c.614A>G (p.Asp205Gly) homozygous missense variant in the TOP3A gene who had CPEO plus syndrome.
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Oftalmoplejía Externa Progresiva Crónica , Oftalmoplejía , Adulto , Humanos , Oftalmoplejía Externa Progresiva Crónica/genética , Oftalmoplejía Externa Progresiva Crónica/patología , Mutación Missense , Homocigoto , Oftalmoplejía/genética , ADN Mitocondrial/genéticaRESUMEN
BACKGROUND: A proportion of de novo variants in patients affected by genetic disorders, particularly those with autosomal dominant (AD) inheritance, could be the consequence of somatic mosaicism in one of the progenitors. There is growing evidence that germline and somatic mosaicism are more common and play a greater role in genetic disorders than previously acknowledged. In Marfan syndrome (MFS), caused by pathogenic variants in the fibrillin-1 gene (FBN1) gene, approximately 25% of the disease-causing variants are reported as de novo. Only a few cases of parental mosaicism have been reported in MFS. METHODS: Employing an amplicon-based deep sequencing (ADS) method, we carried out a systematic analysis of 60 parents of 30 FBN1 positive, consecutive patients with MFS with an apparently de novo pathogenic variant. RESULTS: Out of the 60 parents studied (30 families), the majority (n=51, 85%) had a systemic score of 0, seven had a score of 1 and two a score of 2, all due to minor criteria common in the normal population. We detected two families with somatic mosaicism in one of the progenitors, with a rate of 6.6% (2/30) of apparently de novo cases. CONCLUSIONS: The search for parental somatic mosaicism should be routinely implemented in de novo cases of MFS, to offer appropriate genetic and reproductive counselling as well as to reveal masked, isolated clinical signs of MFS in progenitors that may require specific follow-up.
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Síndrome de Marfan , Fibrilina-1/genética , Humanos , Síndrome de Marfan/patología , Mosaicismo , MutaciónRESUMEN
AIM: To correlate clinical, radiological, and biochemical features with genetic findings in children with bilateral basal ganglia lesions of unknown aetiology, and propose a diagnostic algorithm for early recognition. METHOD: Children with basal ganglia disease were recruited in a 2-year prospective multicentre study for clinical, biomarker, and genetic studies. Radiological pattern recognition was examined by hierarchical clustering analysis. RESULTS: We identified 22 genetic conditions in 30 out of 62 paediatric patients (37 males, 25 females; mean age at onset 2y, SD 3; range 0-10y; mean age at assessment 11y, range 1-25y) through gene panels (n=11), whole-exome sequencing (n=13), and mitochondrial DNA (mtDNA) sequencing (n=6). Genetic aetiologies included mitochondrial diseases (57%), Aicardi-Goutières syndrome (20%), and monogenic causes of dystonia and/or epilepsy (17%) mimicking Leigh syndrome. Radiological abnormalities included T2-hyperintense lesions (n=26) and lesions caused by calcium or manganese mineralization (n=9). Three clusters were identified: the pallidal, neostriatal, and striatal, plus the last including mtDNA defects in the oxidative phosphorylation system with prominent brain atrophy. Mitochondrial biomarkers showed poor sensitivity and specificity in children with mitochondrial disease, whereas interferon signature was observed in all patients with patients with Aicardi-Goutières syndrome. INTERPRETATION: Combined whole-exome and mtDNA sequencing allowed the identification of several genetic conditions affecting basal ganglia metabolism. We propose a diagnostic algorithm which prioritizes early use of next-generation sequencing on the basis of three clusters of basal ganglia lesions.
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Enfermedades de los Ganglios Basales , Enfermedades Mitocondriales , Enfermedades Autoinmunes del Sistema Nervioso , Enfermedades de los Ganglios Basales/diagnóstico , Enfermedades de los Ganglios Basales/genética , Niño , Preescolar , ADN Mitocondrial , Femenino , Humanos , Lactante , Recién Nacido , Imagen por Resonancia Magnética , Masculino , Enfermedades Mitocondriales/diagnóstico , Enfermedades Mitocondriales/genética , Mutación , Malformaciones del Sistema Nervioso , Estudios ProspectivosRESUMEN
Rare diseases (RDs) as a whole affect a huge number of individuals although each specific condition comprises a low number of individuals. As a consequence, funds allocated to expand research to all conditions are often limited. Several initiatives have emerged to invest more resources for research in RDs, but patients express unmet needs regarding educational initiatives, awareness support, and psychosocial resources. We developed an educational training program in the format of weekly sessions covering basic medical scientific knowledge and psychosocial aspects of RDs. The aim of this initiative was to assess its overall impact regarding knowledge, psychological issues, and participant satisfaction. Items were evaluated through surveys before and after the sessions. Here, we report the experience and impact of two editions of this initiative with a total of 37 participants. Our results show improvements in knowledge and better management of the psychological impact. Moreover, participants were able to exchange experiences and concerns, most of which were shared even though the RDs were different. Overall, the program was evaluated by the participants as a highly beneficial experience and all of them were interested in attending advanced editions.
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Enfermedades Raras , Escolaridad , Humanos , Encuestas y CuestionariosRESUMEN
Mitochondrial DNA depletion and multiple deletions syndromes (MDDS) constitute a group of mitochondrial diseases defined by dysfunctional mitochondrial DNA (mtDNA) replication and maintenance. As is the case for many other mitochondrial diseases, the options for the treatment of these disorders are rather limited today. Some aggressive treatments such as liver transplantation or allogeneic stem cell transplantation are among the few available options for patients with some forms of MDDS. However, in recent years, significant advances in our knowledge of the biochemical pathomechanisms accounting for dysfunctional mtDNA replication have been achieved, which has opened new prospects for the treatment of these often fatal diseases. Current strategies under investigation to treat MDDS range from small molecule substrate enhancement approaches to more complex treatments, such as lentiviral or adenoassociated vector-mediated gene therapy. Some of these experimental therapies have already reached the clinical phase with very promising results, however, they are hampered by the fact that these are all rare disorders and so the patient recruitment potential for clinical trials is very limited.
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ADN Mitocondrial , Mitocondrias/genética , Enfermedades Mitocondriales/etiología , Enfermedades Mitocondriales/terapia , Animales , Terapia Combinada , Replicación del ADN , Manejo de la Enfermedad , Susceptibilidad a Enfermedades , Regulación de la Expresión Génica , Humanos , Mitocondrias/metabolismo , Enfermedades Mitocondriales/diagnóstico , Enfermedades Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , MutaciónRESUMEN
Polymerase γ catalytic subunit (POLG) gene encodes the enzyme responsible for mitochondrial DNA (mtDNA) synthesis. Mutations affecting POLG are the most prevalent cause of mitochondrial disease because of defective mtDNA replication and lead to a wide spectrum of clinical phenotypes characterized by mtDNA deletions or depletion. Enhancing mitochondrial deoxyribonucleoside triphosphate (dNTP) synthesis effectively rescues mtDNA depletion in different models of defective mtDNA maintenance due to dNTP insufficiency. In this study, we studied mtDNA copy number recovery rates following ethidium bromide-forced depletion in quiescent fibroblasts from patients harboring mutations in different domains of POLG. Whereas control cells spontaneously recovered initial mtDNA levels, POLG-deficient cells experienced a more severe depletion and could not repopulate mtDNA. However, activation of deoxyribonucleoside (dN) salvage by supplementation with dNs plus erythro-9-(2-hydroxy-3-nonyl) adenine (inhibitor of deoxyadenosine degradation) led to increased mitochondrial dNTP pools and promoted mtDNA repopulation in all tested POLG-mutant cells independently of their specific genetic defect. The treatment did not compromise POLG fidelity because no increase in multiple deletions or point mutations was detected. Our study suggests that physiologic dNTP concentration limits the mtDNA replication rate. We thus propose that increasing mitochondrial dNTP availability could be of therapeutic interest for POLG deficiency and other conditions in which mtDNA maintenance is challenged.-Blázquez-Bermejo, C., Carreño-Gago, L., Molina-Granada, D., Aguirre, J., Ramón, J., Torres-Torronteras, J., Cabrera-Pérez, R., Martín, M. Á., Domínguez-González, C., de la Cruz, X., Lombès, A., García-Arumí, E., Martí, R., Cámara, Y. Increased dNTP pools rescue mtDNA depletion in human POLG-deficient fibroblasts.
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ADN Polimerasa gamma/deficiencia , ADN Mitocondrial/metabolismo , Desoxirribonucleótidos/farmacología , Fibroblastos/metabolismo , Adenina/análogos & derivados , Adenina/farmacología , Adulto , Dominio Catalítico/genética , Células Cultivadas , ADN Polimerasa gamma/genética , Replicación del ADN/efectos de los fármacos , ADN Mitocondrial/genética , Desoxirribonucleótidos/metabolismo , Etidio/farmacología , Femenino , Fibroblastos/efectos de los fármacos , Genotipo , Humanos , Masculino , Mitocondrias Musculares/genética , Modelos Moleculares , Mutación Missense , Fenotipo , Mutación Puntual , Conformación Proteica , Reacción en Cadena en Tiempo Real de la Polimerasa , Eliminación de SecuenciaRESUMEN
Strategies to treat cachexia are still at its infancy. Enhanced muscle protein breakdown and ubiquitin-proteasome system are common features of cachexia associated with chronic conditions including lung cancer (LC). Poly(ADP-ribose) polymerases (PARP), which play a major role in chromatin structure regulation, also underlie maintenance of muscle metabolism and body composition. We hypothesized that protein catabolism, proteolytic markers, muscle fiber phenotype, and muscle anabolism may improve in respiratory and limb muscles of LC-cachectic Parp-1-deficient (Parp-1-/- ) and Parp-2-/- mice. In diaphragm and gastrocnemius of LC (LP07 adenocarcinoma) bearing mice (wild type, Parp-1-/- , and Parp-2-/- ), PARP activity (ADP-ribose polymers, pADPr), redox balance, muscle fiber phenotype, apoptotic nuclei, tyrosine release, protein ubiquitination, muscle-specific E3 ligases, NF-κB signaling pathway, markers of muscle anabolism (Akt, mTOR, p70S6K, and mitochondrial DNA) were evaluated along with body and muscle weights, and limb muscle force. Compared to wild type cachectic animals, in both respiratory and limb muscles of Parp-1-/- and Parp-2-/- cachectic mice: cancer induced-muscle wasting characterized by increased PARP activity, protein oxidation, tyrosine release, and ubiquitin-proteasome system (total protein ubiquitination, atrogin-1, and 20S proteasome C8 subunit) were blunted, the reduction in contractile myosin and atrophy of the fibers was attenuated, while no effects were seen in other structural features (inflammatory cells, internal or apoptotic nuclei), and markers of muscle anabolism partly improved. Activation of either PARP-1 or -2 is likely to play a role in muscle protein catabolism via oxidative stress, NF-κB signaling, and enhanced proteasomal degradation in cancer-induced cachexia. Therapeutic potential of PARP activity inhibition deserves attention.
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Caquexia/etiología , Neoplasias Pulmonares/complicaciones , Fibras Musculares Esqueléticas/enzimología , Proteínas Musculares/metabolismo , Músculo Esquelético/enzimología , Estrés Oxidativo , Poli(ADP-Ribosa) Polimerasa-1/metabolismo , Poli(ADP-Ribosa) Polimerasas/metabolismo , Proteolisis , Animales , Apoptosis , Biomarcadores/metabolismo , Caquexia/enzimología , Caquexia/genética , Caquexia/patología , Línea Celular Tumoral , Diafragma/enzimología , Diafragma/patología , Femenino , Genotipo , Neoplasias Pulmonares/enzimología , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Ratones de la Cepa 129 , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias Musculares/metabolismo , Mitocondrias Musculares/patología , Fibras Musculares Esqueléticas/patología , Músculo Esquelético/patología , FN-kappa B/metabolismo , Tamaño de los Órganos , Fenotipo , Poli(ADP-Ribosa) Polimerasa-1/deficiencia , Poli(ADP-Ribosa) Polimerasa-1/genética , Poli(ADP-Ribosa) Polimerasas/deficiencia , Poli(ADP-Ribosa) Polimerasas/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Transducción de Señal , Factores de Tiempo , UbiquitinaciónRESUMEN
Mitochondrial dysfunction activates mitochondria-to-nucleus signaling pathways whose components are mostly unknown. Identification of these components is important to understand the molecular mechanisms underlying mitochondrial diseases and to discover putative therapeutic targets. MELAS syndrome is a rare neurodegenerative disease caused by mutations in mitochondrial (mt) DNA affecting mt-tRNA(Leu(UUR)). Patient and cybrid cells exhibit elevated oxidative stress. Moreover, mutant mt-tRNAs(Leu(UUR)) lack the taurine-containing modification normally present at the wobble uridine (U34) of wild-type mt-tRNA(Leu(UUR)), which is considered an etiology of MELAS. However, the molecular mechanism is still unclear. We found that MELAS cybrids exhibit a significant decrease in the steady-state levels of several mt-tRNA-modification enzymes, which is not due to transcriptional regulation. We demonstrated that oxidative stress mediates an NFkB-dependent induction of microRNA-9/9*, which acts as a post-transcriptional negative regulator of the mt-tRNA-modification enzymes GTPBP3, MTO1 and TRMU. Down-regulation of these enzymes by microRNA-9/9* affects the U34 modification status of non-mutant tRNAs and contributes to the MELAS phenotype. Anti-microRNA-9 treatments of MELAS cybrids reverse the phenotype, whereas miR-9 transfection of wild-type cells mimics the effects of siRNA-mediated down-regulation of GTPBP3, MTO1 and TRMU. Our data represent the first evidence that an mt-DNA disease can directly affect microRNA expression. Moreover, we demonstrate that the modification status of mt-tRNAs is dynamic and that cells respond to stress by modulating the expression of mt-tRNA-modifying enzymes. microRNA-9/9* is a crucial player in mitochondria-to-nucleus signaling as it regulates expression of nuclear genes in response to changes in the functional state of mitochondria.
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Proteínas Portadoras/genética , Proteínas de Unión al GTP/genética , Síndrome MELAS/genética , MicroARNs/metabolismo , Proteínas Mitocondriales/genética , ARNt Metiltransferasas/genética , Núcleo Celular/genética , Células Cultivadas , Regulación hacia Abajo , Humanos , Mitocondrias/genética , Mitocondrias/metabolismo , FN-kappa B/metabolismo , Estrés Oxidativo , ARN/metabolismo , ARN Mitocondrial , ARN de Transferencia de Leucina/metabolismo , Proteínas de Unión al ARN , Especies Reactivas de Oxígeno/metabolismo , Transducción de SeñalRESUMEN
Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease characterized by bilateral acute or subacute progressive central visual loss. Most cases of LHON syndrome are caused by point mutations in the MT-ND1, MT-ND4, and MT-ND6 genes. Here, we report a novel homoplasmic mutation in the MT-ND1 gene (m.3634A>G, p.Ser110Gly) in a patient with the classical clinical features of LHON syndrome. Several observations support the idea that the mutation is pathogenic and involved in the clinical phenotype of the patient: 1) The mutation affected a highly conserved amino acid, 2) A pathogenic mutation in the same amino acid (m.3635G>A, p.Ser110Asn) was previously reported in a patient with LHON syndrome, 3) The mutation is not recorded in the Mitomap or Human Mitochondrial Genome Database, 4) In silico predictors classified the mutation as "probably damaging", and 5) Cybrids carrying the mutation showed decreased Complex I enzyme activity, lower cell proliferation, and decreased mitochondrial membrane potential relative to control cybrids.
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NADH Deshidrogenasa/genética , Atrofia Óptica Hereditaria de Leber/genética , Mutación Puntual , Adulto , Secuencia de Aminoácidos , Animales , Variaciones en el Número de Copia de ADN , ADN Mitocondrial/genética , Genes Mitocondriales , Humanos , Masculino , NADH Deshidrogenasa/química , Linaje , Alineación de SecuenciaRESUMEN
Left ventricular mass (LVM) is a highly heritable trait and an independent risk factor for all-cause mortality. So far, genome-wide association studies have not identified the genetic factors that underlie LVM variation, and the regulatory mechanisms for blood-pressure-independent cardiac hypertrophy remain poorly understood. Unbiased systems genetics approaches in the rat now provide a powerful complementary tool to genome-wide association studies, and we applied integrative genomics to dissect a highly replicated, blood-pressure-independent LVM locus on rat chromosome 3p. Here we identified endonuclease G (Endog), which previously was implicated in apoptosis but not hypertrophy, as the gene at the locus, and we found a loss-of-function mutation in Endog that is associated with increased LVM and impaired cardiac function. Inhibition of Endog in cultured cardiomyocytes resulted in an increase in cell size and hypertrophic biomarkers in the absence of pro-hypertrophic stimulation. Genome-wide network analysis unexpectedly implicated ENDOG in fundamental mitochondrial processes that are unrelated to apoptosis. We showed direct regulation of ENDOG by ERR-α and PGC1α (which are master regulators of mitochondrial and cardiac function), interaction of ENDOG with the mitochondrial genome and ENDOG-mediated regulation of mitochondrial mass. At baseline, the Endog-deleted mouse heart had depleted mitochondria, mitochondrial dysfunction and elevated levels of reactive oxygen species, which were associated with enlarged and steatotic cardiomyocytes. Our study has further established the link between mitochondrial dysfunction, reactive oxygen species and heart disease and has uncovered a role for Endog in maladaptive cardiac hypertrophy.
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Cardiomegalia/enzimología , Cardiomegalia/patología , Endodesoxirribonucleasas/metabolismo , Mitocondrias/metabolismo , Animales , Apoptosis , Peso Corporal/genética , Cardiomegalia/genética , Cardiomegalia/fisiopatología , Respiración de la Célula , Cromosomas de los Mamíferos/genética , Cruzamientos Genéticos , Endodesoxirribonucleasas/deficiencia , Endodesoxirribonucleasas/genética , Femenino , Regulación de la Expresión Génica , Genes Mitocondriales/genética , Hipertrofia Ventricular Izquierda/enzimología , Hipertrofia Ventricular Izquierda/genética , Hipertrofia Ventricular Izquierda/patología , Hipertrofia Ventricular Izquierda/fisiopatología , Metabolismo de los Lípidos , Masculino , Mitocondrias/genética , Mitocondrias/patología , Tamaño de los Órganos/genética , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Sitios de Carácter Cuantitativo/genética , Proteínas de Unión al ARN/metabolismo , Ratas , Ratas Endogámicas , Especies Reactivas de Oxígeno/metabolismo , Receptores de Estrógenos/metabolismo , Factores de Transcripción/metabolismo , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
Patients with chronic heart failure (CHF) experience exercise intolerance, fatigue and muscle wasting, which negatively influence their survival. We hypothesized that treatment with either the antioxidant N-acetyl cysteine (NAC) or the proteasome inhibitor bortezomib of rats with monocrotaline-induced CHF may restore inspiratory and limb muscle mass, function, and structure through several molecular mechanisms involved in protein breakdown and metabolism in the diaphragm and gastrocnemius. In these muscles of CHF-cachectic rats with and without treatment with NAC or bortezomib (N = 10/group) and non-cachectic controls, proteolysis (tyrosine release, proteasome activities, ubiquitin-proteasome markers), oxidative stress, inflammation, mitochondrial function, myosin, NF-κB transcriptional activity, muscle structural abnormalities, and fiber morphometry were analyzed together with muscle and cardiac functions. In diaphragm and gastrocnemius of CHF-cachectic rats, tyrosine release, proteasome activity, protein ubiquitination, atrogin-1, MURF-1, NF-κB activity, oxidative stress, inflammation, and structural abnormalities were increased, while muscle and cardiac functions, myosin content, slow- and fast-twitch fiber sizes, and mitochondrial activity were decreased. Concomitant treatment of CHF-cachectic rats with NAC or bortezomib improved protein catabolism, oxidative stress, inflammation, muscle fiber sizes, function and damage, superoxide dismutase and myosin levels, mitochondrial function (complex I, gastrocnemius), cardiac function and decreased NF-κB transcriptional activity in both muscles. Treatment of CHF-cachectic animals with NAC or bortezomib attenuated the functional (heart, muscles), biological, and structural alterations in muscles. Nonetheless, future studies conducted in actual clinical settings are warranted in order to assess the potential beneficial effects and safety concerns of these pharmacological agents on muscle mass loss and wasting in CHF-cachectic patients.
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Acetilcisteína/administración & dosificación , Bortezomib/administración & dosificación , Insuficiencia Cardíaca/tratamiento farmacológico , Estrés Oxidativo/efectos de los fármacos , Animales , Diafragma/efectos de los fármacos , Diafragma/metabolismo , Diafragma/patología , Insuficiencia Cardíaca/inducido químicamente , Insuficiencia Cardíaca/metabolismo , Humanos , Mitocondrias/metabolismo , Monocrotalina/toxicidad , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , FN-kappa B/metabolismo , Proteolisis/efectos de los fármacos , RatasRESUMEN
Acquired alterations in mitochondrial DNA are believed to play a pathogenic role in Parkinson's disease. In particular, accumulation of mitochondrial DNA deletions has been observed in substantia nigra pars compacta dopaminergic neurons from patients with Parkinson's disease and aged individuals. Also, mutations in mitochondrial DNA polymerase gamma result in multiple mitochondrial DNA deletions that can be associated with levodopa-responsive parkinsonism and severe substantia nigra pars compacta dopaminergic neurodegeneration. However, whether mitochondrial DNA deletions play a causative role in the demise of dopaminergic neurons remains unknown. Here we assessed the potential pathogenic effects of mitochondrial DNA deletions on the dopaminergic nigrostriatal system by using mutant mice possessing a proofreading-deficient form of mitochondrial DNA polymerase gamma (POLGD257A), which results in a time-dependent accumulation of mitochondrial DNA deletions in several tissues, including the brain. In these animals, we assessed the occurrence of mitochondrial DNA deletions within individual substantia nigra pars compacta dopaminergic neurons, by laser capture microdissection and quantitative real-time polymerase chain reaction, and determined the potential deleterious effects of such mitochondrial DNA alterations on mitochondrial function and dopaminergic neuronal integrity, by cytochrome c oxidase histochemistry and quantitative morphology. Nigral dopaminergic neurons from POLGD257A mice accumulate mitochondrial DNA deletions to a similar extent (â¼40-60%) as patients with Parkinson's disease and aged individuals. Despite such high levels of mitochondrial DNA deletions, the majority of substantia nigra pars compacta dopaminergic neurons from these animals did not exhibit mitochondrial dysfunction or degeneration. Only a few individual substantia nigra pars compacta neurons appeared as cytochrome c oxidase-negative, which exhibited higher levels of mitochondrial DNA deletions than cytochrome c oxidase-positive cells (60.38±3.92% versus 45.18±2.83%). Survival of dopaminergic neurons in POLGD257A mice was associated with increased mitochondrial DNA copy number, enhanced mitochondrial cristae network, improved mitochondrial respiration, decreased exacerbation of mitochondria-derived reactive oxygen species, greater striatal dopamine levels and resistance to parkinsonian mitochondrial neurotoxins. These results indicate that primary accumulation of mitochondrial DNA deletions within substantia nigra pars compacta dopaminergic neurons, at an extent similar to that observed in patients with Parkinson's disease, do not kill dopaminergic neurons but trigger neuroprotective compensatory mechanisms at a mitochondrial level that may account for the high pathogenic threshold of mitochondrial DNA deletions in these cells.
Asunto(s)
Cuerpo Estriado/metabolismo , ADN Mitocondrial/genética , Neuronas Dopaminérgicas/metabolismo , Enfermedad de Parkinson/genética , Sustancia Negra/metabolismo , Animales , Muerte Celular/genética , Cuerpo Estriado/patología , ADN Polimerasa gamma , ADN Mitocondrial/metabolismo , ADN Polimerasa Dirigida por ADN/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Neuronas Dopaminérgicas/patología , Ratones , Ratones Transgénicos , Mitocondrias/genética , Mitocondrias/metabolismo , Mitocondrias/patología , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/patología , Sustancia Negra/patologíaRESUMEN
In 2001, we reported linkage of an autosomal dominant form of limb-girdle muscular dystrophy, limb-girdle muscular dystrophy 1F, to chromosome 7q32.1-32.2, but the identity of the mutant gene was elusive. Here, using a whole genome sequencing strategy, we identified the causative mutation of limb-girdle muscular dystrophy 1F, a heterozygous single nucleotide deletion (c.2771del) in the termination codon of transportin 3 (TNPO3). This gene is situated within the chromosomal region linked to the disease and encodes a nuclear membrane protein belonging to the importin beta family. TNPO3 transports serine/arginine-rich proteins into the nucleus, and has been identified as a key factor in the HIV-import process into the nucleus. The mutation is predicted to generate a 15-amino acid extension of the C-terminus of the protein, segregates with the clinical phenotype, and is absent in genomic sequence databases and a set of >200 control alleles. In skeletal muscle of affected individuals, expression of the mutant messenger RNA and histological abnormalities of nuclei and TNPO3 indicate altered TNPO3 function. Our results demonstrate that the TNPO3 mutation is the cause of limb-girdle muscular dystrophy 1F, expand our knowledge of the molecular basis of muscular dystrophies and bolster the importance of defects of nuclear envelope proteins as causes of inherited myopathies.
Asunto(s)
Eliminación de Gen , Distrofia Muscular de Cinturas/diagnóstico , Distrofia Muscular de Cinturas/genética , beta Carioferinas/genética , Adolescente , Adulto , Anciano , Secuencia de Bases , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Distrofia Muscular de Cinturas/metabolismo , Linaje , beta Carioferinas/biosíntesisRESUMEN
Background: Previous studies found high but very variable levels of tetranor-PGEM and PGDM (urine metabolites of prostaglandin (PG) E2 and PGD2, respectively) in persons with cystic fibrosis (pwCF). This study aims to assess the role of cyclooxygenase COX-1 and COX-2 genetic polymorphisms in PG production and of PG metabolites as potential markers of symptoms' severity and imaging findings. Methods: A total of 30 healthy subjects and 103 pwCF were included in this study. Clinical and radiological CF severity was evaluated using clinical scoring methods and chest computed tomography (CT), respectively. Urine metabolites were measured using liquid chromatography/tandem mass spectrometry. Variants in the COX-1 gene (PTGS1 639 C>A, PTGS1 762+14delA and COX-2 gene: PTGS2-899G>C (-765G>C) and PTGS2 (8473T>C) were also analyzed. Results: PGE-M and PGD-M urine concentrations were significantly higher in pwCF than in controls. There were also statistically significant differences between clinically mild and moderate disease and severe disease. Patients with bronchiectasis and/or air trapping had higher PGE-M levels than patients without these complications. The four polymorphisms did not associate with clinical severity, air trapping, bronchiectasis, or urinary PG levels. Conclusions: These results suggest that urinary PG level testing can be used as a biomarker of CF severity. COX genetic polymorphisms are not involved in the variability of PG production.
RESUMEN
Background/Objectives: Non-Invasive prenatal test (NIPT) is used as a universal or contingent test after prior risk assessment. Screening is mainly performed for common trisomies (T21, T13, T18), although other chromosomal anomalies may be detected. Our objective was to study the performance of GWNIPT in the detection of chromosomal abnormalities in pregnancies in which an invasive prenatal study was performed and in early pregnancy losses, in comparison with the reference test. Method: VeriSeqTM NIPT Solution v2, a genome-wide NIPT (GWNIPT), was performed prior to invasive testing in fetal diagnostic study cases (FDS, n = 155) and in early pregnancy losses (EPL, n = 68). Results: In the FDS group, the diagnostic test (QFPCR, array and karyotype) detected anomalies in 32 pregnancies (21%), in twenty of them (61%) also detected by GWNIPT. Eleven of the twelve cases undetected by GWNIPT were balanced translocations (n = 4) or deletions/duplications <7 Mb (n = 7). In the EPL group, GWNIPT detected anomalies in 46% of cases (31/68) but comparison with reference test (QFPCR and karyotype) in products of conception (POC) was only possible in 18 cases. Concordant results between POC and GWNIPT test were obtained in 16 of the 18 cases. In EPL, with GWNIPT testing, common trisomies accounted for 25.8% of cases (8/31), rare trisomies 54.8% (17/31) and microdeletions/duplications 16.1% (5/31). Conclusions: The GWNIPT test may be useful in clinical practice in prenatal and in EPL's genetic diagnosis when the appropriate sample is not available.