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As a strategy to treat Duchenne muscular dystrophy, we used arginine butyrate, which combines two pharmacological activities: nitric oxide pathway activation, and histone deacetylase inhibition. Continuous intraperitoneal administration to dystrophin-deficient mdx mice resulted in a near 2-fold increase in utrophin (protein homologous to dystrophin) in skeletal muscle, heart, and brain, accompanied by an improvement of the dystrophic phenotype in both adult and newborn mice (45 and 70% decrease in creatine kinase level, respectively; 14% increase in tidal volume, 30% decrease in necrotic area in limb and 23% increase in isometric force). Intermittent administration, as performed in clinical trials, was then used to reduce the frequency of injections and to improve safety. This also enhanced utrophin level around 2-fold (EC50=284 mg/ml) and alleviated the dystrophic phenotype (inverted grid and grip test performance near to wild-type values, creatine kinase level decreased by 50%). Skin biopsies were used to monitor treatment efficacy, instead of invasive muscle biopsies, and this could be done a few days after the start of treatment. A 2-fold increase in utrophin expression was also shown in cultured human myotubes. In vivo and in vitro experiments demonstrated that the drug combination acts synergistically. Together, these data constitute a proof of principle of the beneficial effects of arginine butyrate on muscular dystrophy.
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Arginina/análogos & derivados , Butiratos/uso terapéutico , Distrofia Muscular Animal/tratamiento farmacológico , Distrofia Muscular de Duchenne/tratamiento farmacológico , Animales , Animales Recién Nacidos , Arginina/administración & dosificación , Arginina/uso terapéutico , Butiratos/administración & dosificación , Células Cultivadas , Sinergismo Farmacológico , Inhibidores de Histona Desacetilasas/uso terapéutico , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos mdx , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/metabolismo , Distrofia Muscular Animal/patología , Distrofia Muscular Animal/fisiopatología , Distrofia Muscular de Duchenne/patología , Distrofia Muscular de Duchenne/fisiopatología , Regulación hacia Arriba/efectos de los fármacos , Utrofina/genéticaRESUMEN
OBJECTIVES: Duchenne muscular dystrophy is an X-linked neuromuscular disorder. The heart is traditionally involved, leading to heart failure. The mdx mouse is a natural animal model of the disease. We conducted a prospective study to analyze left ventricular (LV) function in mdx mice at different ages using high-resolution Doppler echocardiography. METHODS: Echocardiography was performed with a 30-MHz cardiac probe. Wild-type and mdx mice were scanned at 10 and 12 months. We measured the interventricular septal wall thickness, posterior wall thickness, and LV diameter in systole and diastole. The LV shortening fraction, LV ejection fraction, and LV mass were then calculated. RESULTS: At 10 months, the shortening fractions in mdx and wild-type mice were relatively close (29% ± 5% versus 25% ± 4%). We found a significant difference in the posterior wall thickness change (40% ± 12% in mdx versus 28% ± 10% in wild-type; P = .048). The LV mass/body weight ratio was higher in mdx than wild-type mice (3.67 ± 0.25 versus 3.39 ± 0.26; P = .05). At 12 months, the LV mass was elevated in mdx mice compared to wild-type (152 ±16 versus 135 ± 3.7 mg; P = .04). The diastolic posterior wall thickness change was decreased in mdx mice at 12 months compared to wild-type (21% ± 7% versus 33% ± 4%; P = .01). The LV ejection fraction was not statistically different between mdx and wild-type mice (50% ± 6% versus 54% ± 2%). CONCLUSIONS: Ten-month-old mdx mice had a significantly higher posterior wall thickness than wild-type mice, but it was not significant at 12 months. In 12-month-old mdx mice, the posterior wall thickness change was significantly lower, and the LV mass was significantly higher. These findings indicate the role of LV function in the early stages of Duchenne muscular dystrophy.
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Algoritmos , Cardiomiopatías/diagnóstico por imagen , Ecocardiografía Doppler/métodos , Interpretación de Imagen Asistida por Computador/métodos , Distrofia Muscular de Duchenne/diagnóstico por imagen , Disfunción Ventricular Izquierda , Animales , Aumento de la Imagen/métodos , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos mdx , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Background: The effects of α and ß adrenergic receptor modulation on the risk of developing heart failure (HF) remains uncertain due to a lack of randomized controlled trials. This study aimed to estimate the effects of α and ß adrenergic receptors modulation on the risk of HF and to provide proof of principle for genetic target validation studies in HF. Methods: Genetic variants within the cis regions encoding the adrenergic receptors α1A, α2B, ß1, and ß2 associated with blood pressure in a 757,601-participant genome-wide association study (GWAS) were selected as instruments to perform a drug target Mendelian randomization study. Effects of these variants on HF risk were derived from the HERMES GWAS (542,362 controls; 40,805 HF cases). Results: Lower α1A or ß1 activity was associated with reduced HF risk: odds ratio (OR) 0.83 (95% CI 0.74-0.93, P = 0.001) and 0.95 (95% CI 0.93-0.97, P = 8 × 10-6). Conversely, lower α2B activity was associated with increased HF risk: OR 1.09 (95% CI 1.05-1.12, P = 3 × 10-7). No evidence of an effect of lower ß2 activity on HF risk was found: OR 0.99 (95% CI 0.92-1.07, P = 0.95). Complementary analyses showed that these effects were consistent with those on left ventricular dimensions and acted independently of any potential effect on coronary artery disease. Conclusions: This study provides genetic evidence that α1A or ß1 receptor inhibition will likely decrease HF risk, while lower α2B activity may increase this risk. Genetic variant analysis can assist with drug development for HF prevention.
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Deficiency of the dysferlin protein presents as two major clinical phenotypes: limb-girdle muscular dystrophy type 2B and Miyoshi myopathy. Dysferlin is known to participate in membrane repair, providing a potential hypothesis to the underlying pathophysiology of these diseases. The size of the dysferlin cDNA prevents its direct incorporation into an adeno-associated virus (AAV) vector for therapeutic gene transfer into muscle. To bypass this limitation, we split the dysferlin cDNA at the exon 28/29 junction and cloned it into two independent AAV vectors carrying the appropriate splicing sequences. Intramuscular injection of the corresponding vectors into a dysferlin-deficient mouse model led to the expression of full-length dysferlin for at least 1 year. Importantly, systemic injection in the tail vein of the two vectors led to a widespread although weak expression of the full-length protein. Injections were associated with an improvement of the histological aspect of the muscle, a reduction in the number of necrotic fibers, restoration of membrane repair capacity and a global improvement in locomotor activity. Altogether, these data support the use of such a strategy for the treatment of dysferlin deficiency.
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Dependovirus/genética , Técnicas de Transferencia de Gen , Terapia Genética , Vectores Genéticos/genética , Proteínas de la Membrana/deficiencia , Proteínas de la Membrana/uso terapéutico , Proteínas Musculares/deficiencia , Proteínas Musculares/uso terapéutico , Distrofia Muscular de Cinturas/genética , Animales , Cruzamientos Genéticos , Disferlina , Femenino , Inyecciones Intramusculares , Masculino , Proteínas de la Membrana/genética , Membranas/patología , Ratones , Ratones Endogámicos C57BL , Proteínas Musculares/genética , Músculo Esquelético/patología , Distrofia Muscular de Cinturas/terapia , Mutación , Fenotipo , Transgenes , Cicatrización de HeridasRESUMEN
AIMS: Acute decompensated heart failure (ADHF), a live-threatening complication of heart failure (HF), associates a further decrease of the already by HF-impaired cardiac function with an increase in heart rate. We evaluated, using a new model of ADHF, whether heart rate reduction (HRR) opposes the acute decompensation-related aggravation of cardiovascular dysfunction. METHODS AND RESULTS: Cardiac output (echocardiography), cardiac tissue perfusion (magnetic resonance imaging), pulmonary wet weight, and in vitro coronary artery relaxation (Mulvany) were assessed 1 and 14 days after acute decompensation induced by salt-loading (1.8 g/kg, PO) in rats with well-established HF due to coronary ligation. HRR was induced by administration of the If current inhibitor S38844, 12 mg/kg PO twice daily for 2.5 days initiated 12 h or 6 days after salt-loading (early or delayed treatment, respectively). After 24 h, salt-loading resulted in acute decompensation, characterized by a reduction in cardiac output (HF: 130 ± 5 mL/min, ADHF: 105 ± 8 mL/min; P < 0.01), associated with a decreased myocardial perfusion (HF: 6.41 ± 0.53 mL/min/g, ADHF: 4.20 ± 0.11 mL/min/g; P < 0.01), a slight increase in pulmonary weight (HF: 1.68 ± 0.09 g, ADHF: 1.81 ± 0.15 g), and impaired coronary relaxation (HF: 55 ± 1% of pre-contraction at acetylcholine 4.5 10-5 M, ADHF: 27 ± 7 %; P < 0.01). Fourteen days after salt-loading, cardiac output only partially recovered (117 ± 5 mL/min; P < 0.05), while myocardial tissue perfusion (4.51 ± 0.44 mL/min; P < 0.01) and coronary relaxation (28 ± 4%; P < 0.01) remained impaired, but pulmonary weight further increased (2.06 ± 0.15 g, P < 0.05). Compared with untreated ADHF, HRR induced by S38844 improved cardiac output (125 ± 1 mL/min; P < 0.05), myocardial tissue perfusion (6.46 ± 0.42 mL/min/g; P < 0.01), and coronary relaxation (79 ± 2%; P < 0.01) as soon as 12 h after S38844 administration. These effects persisted beyond S38844 administration, illustrated by the improvements in cardiac output (130 ± 6 mL/min; P < 0.05), myocardial tissue perfusion (6.38 ± 0.48 mL/min/g; P < 0.01), and coronary relaxation (71 ± 4%; P < 0.01) at Day 14. S38844 did not modify pulmonary weight at Day 1 (1.78 ± 0.04 g) but tended to decrease pulmonary weight at Day 14 (1.80 ± 0.18 g). While delayed HRR induced by S38844 never improved cardiac function, early HRR rendered less prone to a second acute decompensation. CONCLUSIONS: In a model mimicking human ADHF, early, but not delayed, transient HRR induced by the If current inhibitor S38844 opposes acute decompensation by preventing the decompensated-related aggravation of cardiovascular dysfunction as well as the development of pulmonary congestion, and these protective effects persist beyond the transient treatment. Whether early transient HRR induced by If current inhibitors or other bradycardic agents, i.e. beta-blockers, exerts beneficial effects in human ADHF warrants further investigation.
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Insuficiencia Cardíaca , Animales , Gasto Cardíaco , Ecocardiografía , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/etiología , Frecuencia Cardíaca , Ventrículos Cardíacos , RatasRESUMEN
AIMS: The HERMES (HEart failure Molecular Epidemiology for Therapeutic targetS) consortium aims to identify the genomic and molecular basis of heart failure. METHODS AND RESULTS: The consortium currently includes 51 studies from 11 countries, including 68 157 heart failure cases and 949 888 controls, with data on heart failure events and prognosis. All studies collected biological samples and performed genome-wide genotyping of common genetic variants. The enrolment of subjects into participating studies ranged from 1948 to the present day, and the median follow-up following heart failure diagnosis ranged from 2 to 116 months. Forty-nine of 51 individual studies enrolled participants of both sexes; in these studies, participants with heart failure were predominantly male (34-90%). The mean age at diagnosis or ascertainment across all studies ranged from 54 to 84 years. Based on the aggregate sample, we estimated 80% power to genetic variant associations with risk of heart failure with an odds ratio of ≥1.10 for common variants (allele frequency ≥ 0.05) and ≥1.20 for low-frequency variants (allele frequency 0.01-0.05) at P < 5 × 10-8 under an additive genetic model. CONCLUSIONS: HERMES is a global collaboration aiming to (i) identify the genetic determinants of heart failure; (ii) generate insights into the causal pathways leading to heart failure and enable genetic approaches to target prioritization; and (iii) develop genomic tools for disease stratification and risk prediction.
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Estudio de Asociación del Genoma Completo , Insuficiencia Cardíaca , Anciano , Anciano de 80 o más Años , Femenino , Genómica , Insuficiencia Cardíaca/genética , Humanos , Masculino , Persona de Mediana Edad , PronósticoRESUMEN
Myotubular myopathy (XLMTM, OMIM 310400) is a severe congenital muscular disease due to mutations in the myotubularin gene (MTM1) and characterized by the presence of small myofibers with frequent occurrence of central nuclei. Myotubularin is a ubiquitously expressed phosphoinositide phosphatase with a muscle-specific role in man and mouse that is poorly understood. No specific treatment exists to date for patients with myotubular myopathy. We have constructed an adeno-associated virus (AAV) vector expressing myotubularin in order to test its therapeutic potential in a XLMTM mouse model. We show that a single intramuscular injection of this vector in symptomatic Mtm1-deficient mice ameliorates the pathological phenotype in the targeted muscle. Myotubularin replacement in mice largely corrects nuclei and mitochondria positioning in myofibers and leads to a strong increase in muscle volume and recovery of the contractile force. In addition, we used this AAV vector to overexpress myotubularin in wild-type skeletal muscle and get insight into its localization and function. We show that a substantial proportion of myotubularin associates with the sarcolemma and I band, including triads. Myotubularin overexpression in muscle induces the accumulation of packed membrane saccules and presence of vacuoles that contain markers of sarcolemma and T-tubules, suggesting that myotubularin is involved in plasma membrane homeostasis of myofibers. This study provides a proof-of-principle that local delivery of an AAV vector expressing myotubularin can improve the motor capacities of XLMTM muscle and represents a novel approach to study myotubularin function in skeletal muscle.
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Membrana Celular/metabolismo , Terapia Genética , Músculo Esquelético/metabolismo , Miopatías Estructurales Congénitas/genética , Miopatías Estructurales Congénitas/terapia , Proteínas Tirosina Fosfatasas no Receptoras/genética , Animales , Línea Celular , Membrana Celular/química , Membrana Celular/genética , Membrana Celular/patología , Dependovirus/genética , Dependovirus/metabolismo , Femenino , Vectores Genéticos/genética , Homeostasis , Inyecciones Intramusculares , Masculino , Ratones , Músculo Esquelético/química , Músculo Esquelético/patología , Músculo Esquelético/fisiopatología , Miopatías Estructurales Congénitas/metabolismo , Miopatías Estructurales Congénitas/fisiopatología , Fenotipo , Proteínas Tirosina Fosfatasas no Receptoras/administración & dosificación , Proteínas Tirosina Fosfatasas no Receptoras/análisis , Proteínas Tirosina Fosfatasas no Receptoras/metabolismoRESUMEN
MicroRNA (miRNA) inhibition is a promising therapeutic strategy in several disease indications. MRG-110 is a locked nucleic acid-based antisense oligonucleotide that targets miR-92a-3p and experimentally was shown to have documented therapeutic effects on cardiovascular disease and wound healing. To gain first insights into the activity of anti-miR-92a in humans, we investigated miR-92a-3p expression in several blood compartments and assessed the effect of MRG-110 on target derepression. Healthy adults were randomly assigned (5:2) to receive a single intravenous dose of MRG-110 or placebo in one of seven sequential ascending intravenous dose cohorts ranging from 0.01 to 1.5 mg/kg body weight. MiR-92a-3p whole blood levels were time and dose dependently decreased with half-maximal inhibition of 0.27 and 0.31 mg/kg at 24 and 72 h after dosing, respectively. In the high-dose groups, >95% inhibition was detected at 24-72 h postinfusion and significant inhibition was observed for 2 weeks. Similar inhibitory effects were detected in isolated CD31+ cells, and miR-92a-3p expression was also inhibited in extracellular vesicles in the high-dose group. Target derepression was measured in whole blood and showed that ITGA5 and CD93 were increased at a dose of 1.5 mg/kg. Single-cell RNA sequencing of peripheral blood cells revealed a cell type-specific derepression of miR-92a targets. Together this study demonstrates that systemic infusion of anti-miR-92a efficiently inhibits miR-92a in the peripheral blood compartment and derepresses miR-92a targets in humans.
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Enfermedades Cardiovasculares/tratamiento farmacológico , Integrinas/genética , Glicoproteínas de Membrana/genética , MicroARNs/genética , Oligonucleótidos/administración & dosificación , Receptores de Complemento/genética , Adolescente , Adulto , Antagomirs/administración & dosificación , Enfermedades Cardiovasculares/genética , Enfermedades Cardiovasculares/patología , Linaje de la Célula/genética , Vesículas Extracelulares/efectos de los fármacos , Vesículas Extracelulares/genética , Femenino , Humanos , Masculino , MicroARNs/antagonistas & inhibidores , Persona de Mediana Edad , Oligonucleótidos Antisentido/administración & dosificación , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/genética , Cicatrización de Heridas/efectos de los fármacos , Cicatrización de Heridas/genética , Adulto JovenRESUMEN
BACKGROUND: Heart rate (HR) at admission in patients with acute heart failure (AHF) has been shown to be an important risk marker of in-hospital mortality. However, its relation with mid and long-term prognosis as well as the impact of Ejection Fraction (EF) is unknown. Our objective was to study the relationship between long-term survival and HR at admission depending on EF in a cohort of patients hospitalized for AHF. METHODS: We analyzed the data of 2335 patients in sinus rhythm hospitalized for AHF from AHEAD registry. Patients with cardiogenic shock and AHF from surgical or non-cardiac etiology were excluded. RESULTS: Survival rates at 6 and 12 months were 84.8% and 78% respectively. Increased age, decreased diastolic BP, lack of PCI during hospitalization, increased creatinine level and increased HR (with different cut-offs according to EF categories) were found as predictors whatever the EF at 6 and 12 months. Optimal prognostic cut-offs of heart rate were identified for Heart Failure with reduced EF at 100 bpm, for Heart Failure with mid-range EF at 90 bpm and for Heart Failure with preserved EF at 80 bpm for both 6 and 12 months. CONCLUSION: Our study suggests that HR at admission appears to be an independent prognostic parameter in AHF patients in sinus rhythm irrespective of EF and can be used to classify patients according to the severity of the disease.
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Insuficiencia Cardíaca , Intervención Coronaria Percutánea , Frecuencia Cardíaca , Mortalidad Hospitalaria , Hospitalización , Humanos , Lactante , Pronóstico , Sistema de Registros , Volumen SistólicoRESUMEN
Although acetylcholinesterase (AChE) knockout mice survive, they have abnormal neuromuscular function. We analysed further the effects of the mutation on hind limb muscle contractile properties. Tibialis anterior muscle from AChE KO mice is unable to maintain tension during a short period of repetitive nerve stimulation (tetanic fade) and has an increased twitch tension in response to a single nerve electric stimulation. In response to direct muscle stimulation, we found that maximal velocity of shortening of soleus muscle is increased and maximum tetanic force is decreased in AchE KO mice versus control animals. As the contractile properties of the soleus muscle were altered by AChE ablation, our results suggest cellular and molecular changes in AChE ablated muscle containing both fast and slow muscle fibres.
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Acetilcolinesterasa/metabolismo , Músculo Esquelético/fisiología , Acetilcolinesterasa/genética , Animales , Estimulación Eléctrica , Contracción Isométrica , Ratones , Ratones Noqueados , Músculo Esquelético/enzimologíaRESUMEN
α-Sarcoglycanopathy (limb-girdle muscular dystrophy type 2D, LGMD2D) is a recessive muscular disorder caused by deficiency in α-sarcoglycan, a transmembrane protein part of the dystrophin-associated complex. To date, no treatment exists for this disease. We constructed recombinant pseudotype-1 adeno-associated virus (rAAV) vectors expressing the human α-sarcoglycan cDNA from a ubiquitous or a muscle-specific promoter. Evidence of specific immune response leading to disappearance of the vector was observed with the ubiquitous promoter. In contrast, efficient and sustained transgene expression with correct sarcolemmal localization and without evident toxicity was obtained with the muscle-specific promoter after intra-arterial injection into the limbs of an LGMD2D murine model. Transgene expression resulted in restoration of the sarcoglycan complex, histological improvement, membrane stabilization, and correction of pseudohypertrophy. More importantly, α-sarcoglycan transfer produced full rescue of the contractile force deficits and stretch sensibility and led to an increase of the global activity of the animals when both posterior limbs are injected. Our results establish the feasibility for AAV-mediated α-sarcoglycan gene transfer as a therapeutic approach.
RESUMEN
alpha-Sarcoglycanopathy (limb-girdle muscular dystrophy type 2D, LGMD2D) is a recessive muscular disorder caused by deficiency in alpha-sarcoglycan, a transmembrane protein part of the dystrophin-associated complex. To date, no treatment exists for this disease. We constructed recombinant pseudotype-1 adeno-associated virus (rAAV) vectors expressing the human alpha-sarcoglycan cDNA from a ubiquitous or a muscle-specific promoter. Evidence of specific immune response leading to disappearance of the vector was observed with the ubiquitous promoter. In contrast, efficient and sustained transgene expression with correct sarcolemmal localization and without evident toxicity was obtained with the muscle-specific promoter after intra-arterial injection into the limbs of an LGMD2D murine model. Transgene expression resulted in restoration of the sarcoglycan complex, histological improvement, membrane stabilization, and correction of pseudohypertrophy. More importantly, alpha-sarcoglycan transfer produced full rescue of the contractile force deficits and stretch sensibility and led to an increase of the global activity of the animals when both posterior limbs are injected. Our results establish the feasibility for AAV-mediated alpha-sarcoglycan gene transfer as a therapeutic approach.
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Dependovirus/genética , Vectores Genéticos/administración & dosificación , Vectores Genéticos/genética , Músculos/metabolismo , Sarcoglicanos/deficiencia , Sarcoglicanos/metabolismo , Animales , Permeabilidad de la Membrana Celular , Dependovirus/clasificación , Distrofina/metabolismo , Expresión Génica , Regulación de la Expresión Génica , Hipertrofia/genética , Hipertrofia/metabolismo , Hipertrofia/patología , Inyecciones Intraarteriales , Cinética , Ratones , Especificidad de Órganos , Fenotipo , Regiones Promotoras Genéticas/genética , Unión Proteica , Sarcoglicanos/genéticaRESUMEN
OBJECTIVE: Limb-girdle muscular dystophy 2A (LGMD2A, OMIM) is a slowly progressive myopathy caused by the deficiency in calpain 3, a calcium-dependent cysteine protease of the skeletal muscle. METHODS: In this study, we carried out an observational study of clinical manifestations and disease progression in genetically confirmed LGMD2A patients for up to 4 years. A total of 85 patients, aged 14-65 years, were recruited in three centers located in metropolitan France, the Basque country, and the Reunion Island. They were followed up every 6 months for 2 years and a subgroup was assessed annually thereafter for two more years. Data collected for all patients included clinical history, blood parameters, muscle strength assessed by manual muscle testing (MMT) and quantitative muscle testing, functional scores, and pulmonary and cardiac functions. In addition, CT scans of the lower limbs were performed in a subgroup of patients. RESULTS: Our study confirms the clinical description of a slowly progressive disorder with onset in the first or second decade of life with some degree of variability related to gender and mutation type. The null mutations lead to a more severe phenotype while compound heterozygote patients are the least affected. Muscle weakness is remarkably symmetrical and predominant in the axial muscles of the trunk and proximal muscles of the lower limb. There was a high correlation between the weakness at individual muscle level as assessed by MMT and the loss of density in CT scan analysis. INTERPRETATION: All the generated data will help to determine the endpoints for further clinical studies.
RESUMEN
Limb-girdle muscular dystrophy 2D (LGMD2D) is an inherited myogenic disorder belonging to the group of muscular dystrophies. Sgca-null mouse is a knock-out model of LGMD2D. Little is known about cardiac phenotype characterization in this model at different ages. We conducted a prospective study to characterize cardiac sgca-null mice phenotype using high resolution Doppler echocardiography at different ages. Conventional echocardiography was performed on anesthetised mice using a Vevo 770 (Visualsonics) with 30 MHz cardiac probe. Wild Type (WT) and sgca-null mice were scanned at 13, 15 and 17 months. From M-mode, we measured interventricular septal (IVS) wall thickness, posterior wall (PW) thickness, and end-left ventricular diameter in systolic and diastolic. From the above parameters, we calculated left ventricular (LV) shortening fraction (SF), LV ejection fraction (EF) and LV mass. At age 13 months, PW diastolic thickness was increased in sgca-null mice (0.89±0.14 mm vs 0.73±0.2 mm; P=0.020) and LV mass was higher in sgca-null mice (LV mass 205.2 mg vs 143 mg; P=0.001). We found also dilation of the LV (LVEDD: 4.84 mm vs 4.29 mm; P=0.019) in sgca-null mice. At age 15 months, dilation of the LV (LVEDD: 4.86 mm vs 4 mm; P=0.05) with an increase of the LV mass (165.7 mg vs 127.12; P=0.03) are found in sgca-null mice. At age 17 months, we found a decrease of the PW thickening (17% vs 30%; P=0.036). This work provides echocardiographic insights for the assessment of pharmaceutical therapies in sgca-null mice.
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Duchenne muscular dystrophy, a genetic disease caused by the absence of functional dystrophin, remains without adequate treatment. Although great hopes are attached to gene and cell therapies, identification of active small molecules remains a valid option for new treatments. We have studied the effect of 20 approved pharmaceutical compounds on the muscles of dystrophin-deficient mdx5Cv mice. These compounds were selected as the result of a prior screen of 800 approved molecules on a dystrophin mutant of the invertebrate animal model Cænorhabditis elegans. Drugs were administered to the mice through maternal feeding since 2weeks of life and mixed in their food after the 3rd week of life. The effects of the drugs on mice were evaluated both at 6weeks and 16weeks. Each drug was tested at two concentrations. Prednisone was added to the molecule list as a positive control. To investigate treatment efficiency, more than 30 histological, biochemical and functional parameters were recorded. This extensive study reveals that tricyclics (Imipramine and Amitriptyline) are beneficial to the fast muscles of mdx mice. It also highlights a great variability of responses according to time, muscles and assays.
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Aprobación de Drogas/métodos , Evaluación Preclínica de Medicamentos/métodos , Distrofia Muscular de Duchenne/tratamiento farmacológico , Animales , Creatina Quinasa/sangre , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Composición de Medicamentos , Distrofina/genética , Técnicas In Vitro , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos mdx , Contracción Muscular/efectos de los fármacos , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/fisiología , Músculos/efectos de los fármacos , Músculos/patología , Distrofia Muscular de Duchenne/sangre , Distrofia Muscular de Duchenne/patologíaRESUMEN
Calpainopathy (limb-girdle muscular dystrophy type 2A, LGMD2A) is a recessive muscular disorder caused by deficiency in the calcium-dependent cysteine protease calpain 3. To date, no treatment exists for this disease. We evaluated the potential of recombinant adeno-associated virus (rAAV) vectors for gene therapy in a murine model for LGMD2A. To drive the expression of calpain 3, we used rAAV2/1 pseudotyped vectors and muscle-specific promoters to avoid calpain 3 cell toxicity. We report efficient and stable transgene expression in muscle with restoration of the proteolytic activity and without evident toxicity. In addition, calpain 3 was correctly targeted to the sarcomere. Moreover, its presence resulted in improvement of the histological features and in therapeutic efficacy at the physiological levels, including correction of atrophy and full rescue of the contractile force deficits. Our results establish the feasibility of AAV-mediated calpain 3 gene transfer as a therapeutic approach.
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Calpaína/genética , Calpaína/uso terapéutico , Dependovirus/genética , Técnicas de Transferencia de Gen , Terapia Genética/métodos , Proteínas Musculares/genética , Proteínas Musculares/uso terapéutico , Distrofia Muscular de Cinturas/terapia , Animales , Calpaína/biosíntesis , Calpaína/deficiencia , Modelos Animales de Enfermedad , Activación Enzimática/genética , Estabilidad de Enzimas/genética , Vectores Genéticos/uso terapéutico , Inyecciones Intramusculares , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas Musculares/biosíntesis , Proteínas Musculares/deficiencia , Músculo Esquelético/enzimología , Distrofia Muscular de Cinturas/metabolismoRESUMEN
Defects in human calpain 3 are responsible for limb-girdle muscular dystrophy type 2A, an autosomal-recessive disorder characterized mainly by late-onset proximal muscular atrophy. A corresponding murine model has previously been generated by gene targeting. In this report, muscular activity of calpain 3-deficient (capn3(-/-)) mice was evaluated at different ages. Growth curves showed a progressive global muscular atrophy. Histological examination throughout the lifespan of mice confirmed the dystrophic lesions. Whole animal tests showed only a mild significant impairment of the forelimbs. Studies of the mechanical properties of selected isolated fast- and slow-twitch muscles demonstrated that slow-twitch muscles were significantly weaker in capn3(-/-) mice than in wild-type mice. Three different tests showed that there was no membrane disruption, suggesting a nonmechanical etiology of capn3(-/-) mice dystrophy. These findings are consistent with a mechanism involving signaling systems.
Asunto(s)
Calpaína/genética , Calpaína/metabolismo , Proteínas Musculares , Músculo Esquelético/fisiología , Distrofias Musculares/metabolismo , Animales , Modelos Animales de Enfermedad , Impedancia Eléctrica , Femenino , Ratones , Ratones Mutantes , Contracción Muscular/fisiología , Fibras Musculares de Contracción Rápida/metabolismo , Fibras Musculares de Contracción Lenta/metabolismo , Músculo Esquelético/citología , Distrofias Musculares/genética , Distrofias Musculares/fisiopatología , FenotipoRESUMEN
Most mutations in the dystrophin gene create a frameshift or a stop in the mRNA and are associated with severe Duchenne muscular dystrophy. Exon skipping that naturally occurs at low frequency sometimes eliminates the mutation and leads to the production of a rescued protein. We have achieved persistent exon skipping that removes the mutated exon on the dystrophin messenger mRNA of the mdx mouse, by a single administration of an AAV vector expressing antisense sequences linked to a modified U7 small nuclear RNA. We report the sustained production of functional dystrophin at physiological levels in entire groups of muscles and the correction of the muscular dystrophy.
Asunto(s)
Distrofina/genética , Exones , Terapia Genética , Distrofia Muscular Animal/terapia , Distrofia Muscular de Duchenne/terapia , Mutación , Oligonucleótidos Antisentido/farmacología , ARN Nuclear Pequeño/metabolismo , Animales , Dependovirus/genética , Distrofina/metabolismo , Vectores Genéticos , Intrones , Ratones , Ratones Endogámicos mdx , Contracción Muscular , Fibras Musculares Esqueléticas/inmunología , Fibras Musculares Esqueléticas/patología , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Músculo Esquelético/fisiología , Distrofia Muscular Animal/genética , Distrofia Muscular Animal/patología , Distrofia Muscular Animal/fisiopatología , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patología , Distrofia Muscular de Duchenne/fisiopatología , Empalme del ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Nuclear Pequeño/genética , TransfecciónRESUMEN
This report describes the characterisation of the expression profile of several myogenic determination genes during human embryogenesis. The data were obtained from axial structures and limb buds of human embryos aged between 3 and 8 weeks of development. Using in situ hybridisation to detect Pax3 and MyoD gene family mRNAs, and immunochemistry to follow Six and Eya protein accumulation, we have been able to establish the chronology of accumulation of these gene products. As in mouse, the first transcripts detected in myotomes of 3 week-old embryos are Pax3 and Myf5, followed by the expression of myogenin. MyoD appears to be activated well after Myf5, myogenin and MRF4 in the early myotome, whereas, in limb bud muscles, the presence of all four of these mRNAs is concomitant from 6 weeks. Six1, Six4 and Six5 homeoproteins are detected later than Myf5 activation. These Six homeoproteins are first observed in the cytoplasm of myogenin expressing cells. At later stages of development, Six1 and Six5, but not Six4, are translocated into the nuclei of myogenic cells, concomitantly with MyHCemb expression. Eya1 and Eya2 proteins, potential Six cofactors, were also detected in myogenin positive cells, but their accumulation was delayed and was mainly cytoplasmic. These results preclude that early activation of Myf5, myogenin and MRF4 is under the control of Six and Eya proteins, while Six and Eya proteins would be involved in later steps of myogenic differentiation.