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1.
Muscle Nerve ; 68(2): 157-170, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37409780

RESUMEN

INTRODUCTION/AIMS: NURTURE (NCT02386553) is an open-label study of nusinersen in children (two SMN2 copies, n = 15; three SMN2 copies, n = 10) who initiated treatment in the presymptomatic stage of spinal muscular atrophy (SMA). A prior analysis after ~3 y showed benefits on survival, respiratory outcomes, motor milestone achievement, and a favorable safety profile. An additional 2 y of follow-up (data cut: February 15, 2021) are reported. METHODS: The primary endpoint is time to death or respiratory intervention (≥6 h/day continuously for ≥7 days or tracheostomy). Secondary outcomes include overall survival, motor function, and safety. RESULTS: Median age of children was 4.9 (3.8-5.5) y at last visit. No children have discontinued the study or treatment. All were alive. No additional children utilized respiratory intervention (defined per primary endpoint) since the prior data cut. Children with three SMN2 copies achieved all World Health Organization (WHO) motor milestones, with all but one milestone in one child within normal developmental timeframes. All 15 children with two SMN2 copies achieved sitting without support, 14/15 walking with assistance, and 13/15 walking alone. Mean Hammersmith Functional Motor Scale Expanded total scores showed continued improvement. Subgroups with two SMN2 copies, minimum baseline compound muscle action potential amplitude ≥2 mV, and no baseline areflexia had better motor and nonmotor outcomes versus all children with two SMN2 copies. DISCUSSION: These results demonstrate the value of early treatment, durability of treatment effect, and favorable safety profile after ~5 y of nusinersen treatment. Inclusion/exclusion criteria and baseline characteristics should be considered when interpreting presymptomatic SMA trial data.


Asunto(s)
Atrofia Muscular Espinal , Atrofias Musculares Espinales de la Infancia , Niño , Humanos , Atrofia Muscular Espinal/tratamiento farmacológico , Oligonucleótidos/uso terapéutico , Caminata , Atrofias Musculares Espinales de la Infancia/tratamiento farmacológico
2.
J Neurochem ; 129(5): 884-94, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24494600

RESUMEN

Aggregate-prone mutant proteins, such as α-synuclein and huntingtin, play a prominent role in the pathogenesis of various neurodegenerative disorders; thus, it has been hypothesized that reducing the aggregate-prone proteins may be a beneficial therapeutic strategy for these neurodegenerative disorders. Here, we identified two previously described glucosylceramide (GlcCer) synthase inhibitors, DL-threo-1-Phenyl-2-palmitoylamino-3-morpholino-1-propanol and Genz-123346(Genz), as enhancers of autophagy flux. We also demonstrate that GlcCer synthase inhibitors exert their effects on autophagy by inhibiting AKT-mammalian target of rapamycin (mTOR) signaling. More importantly, siRNA knock down of GlcCer synthase had the similar effect as pharmacological inhibition, confirming the on-target effect. In addition, we discovered that inhibition of GlcCer synthase increased the number and size of lysosomal/late endosomal structures. Although inhibition of GlcCer synthase decreases levels of mutant α-synuclein in neurons, it does so, according to our data, through autophagy-independent mechanisms. Our findings demonstrate a direct link between glycosphingolipid biosynthesis and autophagy in primary neurons, which may represent a novel pathway with potential therapeutic value for the treatment of Parkinson's disease. Inhibition of GlcCer synthase enhances autophagy by inhibiting AKT-mTOR signaling, and increases the number and size of lysosomal/late endosomal structures. Furthermore, inhibition of GlcCer synthase decreased levels of mutant α-synuclein in neurons, which may represent a potential therapeutic target for Parkinson's disease.


Asunto(s)
Autofagia/fisiología , Inhibidores Enzimáticos/farmacología , Glucosiltransferasas/antagonistas & inhibidores , Neuronas/fisiología , Animales , Western Blotting , Células Cultivadas , Dioxanos/farmacología , Femenino , Glicoesfingolípidos/biosíntesis , Células HEK293 , Humanos , Masculino , Meperidina/análogos & derivados , Meperidina/farmacología , Ratones , Ratones Noqueados , Ratones Transgénicos , Proteína Oncogénica v-akt/metabolismo , Enfermedad de Parkinson/genética , Fosforilación , Cultivo Primario de Células , Pirrolidinas/farmacología , ARN Interferente Pequeño/genética , Reacción en Cadena en Tiempo Real de la Polimerasa
3.
Bioorg Med Chem Lett ; 24(17): 4132-40, 2014 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-25113930
4.
Nat Genet ; 37(7): 771-6, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15980862

RESUMEN

Mutations that affect the dynein motor machinery are sufficient to cause motor neuron disease. It is not known why there are aggregates or inclusions in affected tissues in mice with such mutations and in most forms of human motor neuron disease. Here we identify a new mechanism of inclusion formation by showing that decreased dynein function impairs autophagic clearance of aggregate-prone proteins. We show that mutations of the dynein machinery enhanced the toxicity of the mutation that causes Huntington disease in fly and mouse models. Furthermore, loss of dynein function resulted in premature aggregate formation by mutant huntingtin and increased levels of the autophagosome marker LC3-II in both cell culture and mouse models, compatible with impaired autophagosome-lysosome fusion.


Asunto(s)
Adenina/análogos & derivados , Autofagia , Dineínas/genética , Enfermedad de Huntington/patología , Mutación , Adenina/farmacología , Adenilil Imidodifosfato/farmacología , Animales , Conducta Animal , Encéfalo/patología , Células COS , Chlorocebus aethiops , Cruzamientos Genéticos , Dípteros , Dineínas/antagonistas & inhibidores , Dineínas/metabolismo , Humanos , Proteína Huntingtina , Enfermedad de Huntington/genética , Enfermedad de Huntington/metabolismo , Cuerpos de Inclusión/metabolismo , Ratones , Ratones Mutantes , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nucleares/genética , Células PC12 , Complejo de la Endopetidasa Proteasomal/metabolismo , Ratas , Sinucleínas
5.
Adv Ther ; 41(7): 2743-2756, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38722537

RESUMEN

INTRODUCTION: Spinal muscular atrophy (SMA) is a rare, autosomal recessive, neuromuscular disease that leads to progressive muscular weakness and atrophy. Nusinersen, an antisense oligonucleotide, was approved for SMA in China in February 2019. We report interim results from a post-marketing surveillance phase 4 study, PANDA (NCT04419233), that collects data on the safety, efficacy, and pharmacokinetics of nusinersen in children with SMA in routine clinical practice in China. METHODS: Participants enrolled in PANDA will be observed for 2 years following nusinersen treatment initiation. The primary endpoint is the incidence of adverse events (AEs)/serious AEs (SAEs) during the treatment period. Efficacy assessments include World Health Organization (WHO) Motor Milestones assessment, the Hammersmith Infant Neurological Examination (HINE), and ventilation support. Plasma and cerebrospinal fluid (CSF) concentrations of nusinersen are measured at each dose visit. RESULTS: Fifty participants were enrolled as of the January 4, 2023, data cutoff: 10 with infantile-onset (≤ 6 months) and 40 with later-onset (> 6 months) SMA. All 50 participants have received at least one dose of nusinersen; 6 have completed the study. AEs were experienced by 45 (90%) participants and were mostly mild/moderate; no AEs led to nusinersen discontinuation or study withdrawal. Eleven participants experienced SAEs, most commonly pneumonia (n = 9); none were considered related to study treatment. Stability or gain of WHO motor milestone was observed and mean HINE-2 scores improved in both subgroups throughout the study. No serious respiratory events occurred, and no permanent ventilation support was initiated during the study. Pre-dose nusinersen CSF concentrations increased steadily through the loading-dose period, with no accumulation in plasma after multiple doses. CONCLUSION: Nusinersen was generally well tolerated with an acceptable overall safety profile, consistent with the known safety of nusinersen. Efficacy, safety, and nusinersen exposure are consistent with prior observations. These results support continuing PANDA and evaluation of nusinersen in Chinese participants with SMA. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT04419233.


Asunto(s)
Oligonucleótidos , Vigilancia de Productos Comercializados , Humanos , Oligonucleótidos/uso terapéutico , Oligonucleótidos/efectos adversos , Lactante , China , Masculino , Femenino , Preescolar , Atrofia Muscular Espinal/tratamiento farmacológico , Resultado del Tratamiento , Atrofias Musculares Espinales de la Infancia/tratamiento farmacológico
6.
Nat Genet ; 36(6): 585-95, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15146184

RESUMEN

Huntington disease is one of nine inherited neurodegenerative disorders caused by a polyglutamine tract expansion. Expanded polyglutamine proteins accumulate abnormally in intracellular aggregates. Here we show that mammalian target of rapamycin (mTOR) is sequestered in polyglutamine aggregates in cell models, transgenic mice and human brains. Sequestration of mTOR impairs its kinase activity and induces autophagy, a key clearance pathway for mutant huntingtin fragments. This protects against polyglutamine toxicity, as the specific mTOR inhibitor rapamycin attenuates huntingtin accumulation and cell death in cell models of Huntington disease, and inhibition of autophagy has the converse effects. Furthermore, rapamycin protects against neurodegeneration in a fly model of Huntington disease, and the rapamycin analog CCI-779 improved performance on four different behavioral tasks and decreased aggregate formation in a mouse model of Huntington disease. Our data provide proof-of-principle for the potential of inducing autophagy to treat Huntington disease.


Asunto(s)
Enfermedad de Huntington/tratamiento farmacológico , Inhibidores de Proteínas Quinasas , Animales , Autofagia , Células COS , Modelos Animales de Enfermedad , Drosophila melanogaster , Femenino , Humanos , Proteína Huntingtina , Enfermedad de Huntington/genética , Enfermedad de Huntington/metabolismo , Sustancias Macromoleculares , Masculino , Ratones , Ratones Transgénicos , Mutación , Proteínas del Tejido Nervioso/química , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Péptidos/química , Péptidos/genética , Péptidos/metabolismo , Biosíntesis de Proteínas , Proteínas Quinasas/metabolismo , Sirolimus/farmacología , Serina-Treonina Quinasas TOR
7.
J Neuromuscul Dis ; 10(5): 813-823, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37393513

RESUMEN

BACKGROUND: Pharmacokinetic/pharmacodynamic modeling indicates that the higher dose of nusinersen may be associated with a clinically meaningful increase in efficacy above that seen with the 12-mg approved dose. OBJECTIVE: Here we describe both the design of DEVOTE (NCT04089566), a 3-part clinical study evaluating safety, tolerability, and efficacy of higher dose of nusinersen, and results from the initial Part A. METHODS: DEVOTE Part A evaluates safety and tolerability of a higher nusinersen dose; Part B assesses efficacy in a randomized, double-blind design; and Part C assesses safety and tolerability of participants transitioning from the 12-mg dose to higher doses. RESULTS: In the completed Part A of DEVOTE, all 6 enrolled participants aged 6.1-12.6 years have completed the study. Four participants experienced treatment-emergent adverse events (TEAEs), the majority of which were mild. Common TEAEs of headache, pain, chills, vomiting, and paresthesia were considered related to the lumbar puncture procedure. There were no safety concerns regarding clinical or laboratory parameters. Nusinersen levels in the cerebrospinal fluid were within the range of modeled predictions for higher dose of nusinersen. While Part A was not designed for assessing efficacy, most participants showed stabilization or improvement in motor function. Parts B and C of DEVOTE are ongoing. CONCLUSIONS: The findings from Part A of the DEVOTE study support further development of higher dose of nusinersen.


Asunto(s)
Atrofia Muscular Espinal , Humanos , Atrofia Muscular Espinal/tratamiento farmacológico , Oligonucleótidos/efectos adversos , Dolor , Proyectos de Investigación , Niño
8.
J Clin Med ; 12(15)2023 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-37568304

RESUMEN

Nusinersen has been shown to improve or stabilize motor function in individuals with spinal muscular atrophy (SMA). We evaluated baseline scoliosis severity and motor function in nusinersen-treated non-ambulatory children with later-onset SMA. Post hoc analyses were conducted on 95 children initiating nusinersen treatment in the CHERISH study or SHINE long-term extension trial. Participants were categorized by baseline Cobb angle (first nusinersen dose): ≤10°, >10° to ≤20°, and >20° to <40° (no/mild/moderate scoliosis, respectively). Outcome measures included the Hammersmith Functional Motor Score-Expanded (HFMSE) and the Revised Upper Limb Module (RULM). Regression analysis determined the relationships between baseline scoliosis severity and later motor function. For children with no, mild, and moderate scoliosis, the mean increase in HFMSE from baseline to Day 930 was 6.0, 3.9, and 0.7 points, and in RULM was 6.1, 4.6, and 2.3 points. In the linear model, a 10° increase in baseline Cobb angle was significantly associated with a -1.4 (95% CI -2.6, -0.2) point decrease in HFMSE (p = 0.02) and a -1.2 (95% CI -2.1, -0.4) point decrease in RULM (p = 0.006) at Day 930. Treatment with nusinersen was associated with improvements/stabilization in motor function in all groups, with greater response in those with no/mild scoliosis at baseline.

9.
CPT Pharmacometrics Syst Pharmacol ; 12(2): 196-206, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36471456

RESUMEN

Phosphorylated neurofilament heavy subunit (pNfH) has been recently identified as a promising biomarker of disease onset and treatment efficacy in spinal muscular atrophy (SMA). This study introduces a quantitative systems pharmacology model representing the SMA pediatric scenario in the age range of 0-20 years with and without treatment with the antisense oligonucleotide nusinersen. Physiological changes typical of the pediatric age and the contribution of SMA and its treatment to the peripheral pNfH levels were included in the model by extending the equations of a previously developed mathematical model describing the neurofilament trafficking in healthy adults. All model parameters were estimated by fitting data from clinical trials that enrolled SMA patients treated with nusinersen. The data from the control group of the study was employed to build an in silico population of untreated subjects, and the parameters related to the treatment were estimated by fitting individual pNfH time series of SMA patients followed during the treatment. The final model reproduces well the pNfH levels in the presence of SMA in both the treated and untreated conditions. The results were validated by comparing model predictions with the data obtained from an additional cohort of SMA patients. The reported good predictive model performance makes it a valuable tool for investigating pNfH as a biomarker of disease progression and treatment response in SMA and for the in silico evaluation of novel treatment protocols.


Asunto(s)
Atrofia Muscular Espinal , Oligonucleótidos Antisentido , Adulto , Humanos , Niño , Recién Nacido , Lactante , Preescolar , Adolescente , Adulto Joven , Oligonucleótidos Antisentido/farmacología , Oligonucleótidos Antisentido/uso terapéutico , Filamentos Intermedios , Farmacología en Red , Atrofia Muscular Espinal/tratamiento farmacológico , Biomarcadores
10.
Nature ; 442(7105): 916-9, 2006 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-16862116

RESUMEN

Frontotemporal dementia (FTD) is the second most common cause of dementia in people under the age of 65 years. A large proportion of FTD patients (35-50%) have a family history of dementia, consistent with a strong genetic component to the disease. In 1998, mutations in the gene encoding the microtubule-associated protein tau (MAPT) were shown to cause familial FTD with parkinsonism linked to chromosome 17q21 (FTDP-17). The neuropathology of patients with defined MAPT mutations is characterized by cytoplasmic neurofibrillary inclusions composed of hyperphosphorylated tau. However, in multiple FTD families with significant evidence for linkage to the same region on chromosome 17q21 (D17S1787-D17S806), mutations in MAPT have not been found and the patients consistently lack tau-immunoreactive inclusion pathology. In contrast, these patients have ubiquitin (ub)-immunoreactive neuronal cytoplasmic inclusions and characteristic lentiform ub-immunoreactive neuronal intranuclear inclusions. Here we demonstrate that in these families, FTD is caused by mutations in progranulin (PGRN) that are likely to create null alleles. PGRN is located 1.7 Mb centromeric of MAPT on chromosome 17q21.31 and encodes a 68.5-kDa secreted growth factor involved in the regulation of multiple processes including development, wound repair and inflammation. PGRN has also been strongly linked to tumorigenesis. Moreover, PGRN expression is increased in activated microglia in many neurodegenerative diseases including Creutzfeldt-Jakob disease, motor neuron disease and Alzheimer's disease. Our results identify mutations in PGRN as a cause of neurodegenerative disease and indicate the importance of PGRN function for neuronal survival.


Asunto(s)
Cromosomas Humanos Par 17/genética , Demencia/genética , Lóbulo Frontal/fisiopatología , Péptidos y Proteínas de Señalización Intercelular/genética , Mutación/genética , Precursores de Proteínas/genética , Lóbulo Temporal/fisiopatología , Supervivencia Celular , Codón de Terminación/genética , Demencia/fisiopatología , Lóbulo Frontal/metabolismo , Ligamiento Genético/genética , Humanos , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Neuronas/metabolismo , Neuronas/patología , Mapeo Físico de Cromosoma , Progranulinas , Precursores de Proteínas/metabolismo , Estabilidad del ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Lóbulo Temporal/metabolismo , Proteínas tau/deficiencia , Proteínas tau/genética
11.
Ann Clin Transl Neurol ; 9(6): 819-829, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35567345

RESUMEN

OBJECTIVE: The long-term favorable safety profile of nusinersen provides an opportunity to consider a higher dose. We report on the relationships between nusinersen cerebrospinal fluid (CSF) exposure, biomarker levels, and clinical efficacy. METHODS: The analyses used data from the CS3A and ENDEAR studies of nusinersen in participants with infantile-onset spinal muscular atrophy (SMA). Steady-state CSF trough (Ctrough ) levels, plasma phosphorylated neurofilament heavy chain (pNF-H) levels, body weight, and Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) scores were selected as parameters of interest. A validated population pharmacokinetic (PK) model was applied to predict the nusinersen CSF Ctrough . PK/pharmacodynamic (PK/PD) models used nusinersen CSF Ctrough measurements, which were time-matched with CHOP INTEND scores. RESULTS: Higher nusinersen CSF exposure was associated with a greater decrease in pNF-H levels and greater efficacy, as measured by change in the CHOP INTEND score from baseline. These findings indicate a dose-response relationship between CSF nusinersen levels and treatment response. The higher dose is predicted to lead to approximately a 2.4-fold increase in nusinersen CSF levels with fewer loading doses. PK/PD modeling indicates that a higher concentration of nusinersen may predict an additional 5-point increase in CHOP INTEND score beyond that observed with 12 mg. INTERPRETATION: Our data indicate that a higher dose of nusinersen may lead to additional clinically meaningful improvement in efficacy when compared with the currently approved 12-mg dose. The efficacy, safety, and PK of a higher nusinersen dose are currently under investigation in the ongoing phase 2/3 DEVOTE study (NCT04089566).


Asunto(s)
Atrofias Musculares Espinales de la Infancia , Biomarcadores , Niño , Humanos , Lactante , Oligonucleótidos/farmacocinética , Atrofias Musculares Espinales de la Infancia/tratamiento farmacológico , Resultado del Tratamiento
12.
CNS Drugs ; 36(2): 181-190, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-35080757

RESUMEN

BACKGROUND: Nusinersen is approved for the treatment of spinal muscular atrophy. The most common approved dosing regimen is four intrathecal loading doses of nusinersen 12 mg; the first three are administered at 14-day intervals followed by a fourth dose 30 days later, and then 12-mg maintenance doses are administered every 4 months thereafter. Interruption of nusinersen treatment in the maintenance dosing phase might occur for a number of clinical reasons. OBJECTIVE: The objective of this report is to describe dosing regimens that allow for the most rapid restoration of steady-state concentrations of nusinersen in the cerebrospinal fluid (CSF) following a treatment interruption during maintenance dosing. METHODS: Population pharmacokinetic models using integrated pharmacokinetic data from ten nusinersen clinical trials that included a broad range of participants with spinal muscular atrophy treated with intrathecal nusinersen were used to investigate different durations of treatment interruptions during maintenance treatment. Potential dosing regimens for re-initiation of nusinersen were evaluated, with the goal of achieving the quickest restoration of steady-state nusinersen CSF concentrations without exceeding maximal CSF exposures observed during the initial loading period. RESULTS: Our pharmacokinetic modeling indicates the following regimen will lead to optimal restoration of nusinersen CSF levels after treatment interruption: two doses of nusinersen should be administered at 14-day intervals following treatment interruptions of ≥ 8 to < 16 months since the last dose, and three doses of nusinersen at 14-day intervals for treatment interruptions of ≥ 16 to < 40 months since the last maintenance dose, with subsequent maintenance dosing every 4 months in both instances. After treatment interruptions of ≥ 40 months, the full loading regimen will rapidly restore nusinersen CSF levels. CONCLUSIONS: Prolonged treatment interruptions lead to suboptimal CSF levels of nusinersen. The optimal regimen to restore nusinersen CSF levels depends on the interval since the last maintenance dose was administered.


Nusinersen is a drug used to treat people of all ages who have spinal muscular atrophy. Nusinersen is injected with a thin needle into the lower back, a procedure known as a lumbar puncture. People initially receive three doses of nusinersen 12 mg each 14 days apart. They receive a fourth dose 1 month later, and then injections every 4 months (known as maintenance dosing). This treatment plan allows nusinersen to build up to effective levels in the fluid surrounding the spinal cord and brain. Some people may miss dose(s) or may stop nusinersen treatment at some point during maintenance dosing and then may want to continue treatment. This study used information from ten clinical trials to find out the best way to restart treatment to build up nusinersen to effective levels. People with a treatment break of ≥ 8 to < 16 months since the last dose need two doses of nusinersen at 14-day intervals before receiving maintenance dosing. People with a treatment break of ≥ 16 to < 40 months since the last dose need three doses of nusinersen at 14-day intervals before receiving maintenance dosing. If people stopped treatment for ≥ 40 months, they would need four doses before starting maintenance treatment. Results from this study showed that the number of doses that people needed before starting maintenance treatment depended on how long the treatment break was.


Asunto(s)
Relación Dosis-Respuesta a Droga , Monitoreo de Drogas/métodos , Quimioterapia de Mantención/métodos , Atrofia Muscular Espinal , Oligonucleótidos , Esquema de Medicación , Duración de la Terapia , Humanos , Inyecciones Espinales/métodos , Modelos Biológicos , Atrofia Muscular Espinal/líquido cefalorraquídeo , Atrofia Muscular Espinal/tratamiento farmacológico , Oligonucleótidos/administración & dosificación , Oligonucleótidos/líquido cefalorraquídeo , Oligonucleótidos/farmacocinética , Oligonucleótidos Antisentido/administración & dosificación , Oligonucleótidos Antisentido/líquido cefalorraquídeo , Oligonucleótidos Antisentido/farmacocinética , Resultado del Tratamiento
13.
Neuromuscul Disord ; 31(4): 310-318, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33781694

RESUMEN

Nusinersen is an antisense oligonucleotide approved for the treatment of spinal muscular atrophy. The drug is given intrathecally at 12 mg, beginning with 3 loading doses at 2-week intervals, a fourth loading dose 30 days thereafter, and maintenance doses at 4-month intervals. This population pharmacokinetic model was developed to clarify how to maintain targeted nusinersen exposure after an unforeseen one-time delay or missed dose. Simulations demonstrated that the impact of a one-time delay in dosing or a missed dose on median cerebrospinal fluid exposures depended on duration of interruption and the regimen phase in which it occurred. Delays in loading doses delayed reaching the peak trough concentration by approximately the duration of the interruption. Resumption of the regimen as soon as possible resulted in achieving steady state trough concentration upon completion of the loading phase. A short delay (30-90 days) during the maintenance phase led to prolonged lower median cerebrospinal fluid concentration if all subsequent doses were shifted by the same 4-month interval. However, administration of the delayed dose, followed by the subsequent dose as originally scheduled, rapidly restored trough concentration. If a dose must be delayed, patients should return to the original dosing schedule as soon as possible.


Asunto(s)
Atrofia Muscular Espinal/tratamiento farmacológico , Oligonucleótidos/farmacocinética , Humanos , Oligonucleótidos/administración & dosificación
14.
Biochemistry ; 49(26): 5511-23, 2010 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-20515039

RESUMEN

Autosomal dominant mutations in leucine rich repeat kinase 2 (LRRK2) are the most common genetic cause of Parkinson's disease (PD). Despite the presence of multiple domains, the kinase activity of LRRK2 is thought to represent the primary function of the protein. Alterations in LRRK2 kinase activity are thought to underlie the pathogenesis of its PD-linked mutations; however, many questions regarding basic aspects of LRRK2 function remain unclear, including the cellular mechanisms of LRRK2 regulation and the importance of its unique distribution within the cell. Here, we demonstrate for the first time that the subcellular localization of wild-type LRRK2 is associated with changes in four distinct biochemical properties likely crucial for LRRK2 function. Our data demonstrate for the first time that the wild-type LRRK2 dimer possesses greater kinase activity than its more abundant monomeric counterpart. Importantly, we show that this activated form of LRRK2 is substantially enriched at the membrane of cells expressing endogenous or exogenous LRRK2, and that the membrane-associated fraction of LRRK2 likewise possesses greater kinase activity than cytosolic LRRK2. In addition, membrane-associated LRRK2 binds GTP more efficiently than cytosolic LRRK2 but demonstrates a lower degree of phosphorylation. Our observations suggest that multiple events, including altered protein-protein interactions and post-translational modifications, contribute to the regulation of LRRK2 function, through modulation of membrane association and complex assembly. These findings may have implications for the sites of LRRK2 function within the cell, the identification and localization of bona fide LRRK2 substrates, and efforts to design small molecule inhibitors of LRRK2.


Asunto(s)
Membrana Celular/metabolismo , Multimerización de Proteína , Proteínas Serina-Treonina Quinasas/análisis , Línea Celular , Citosol , Activación Enzimática , Guanosina Trifosfato/metabolismo , Humanos , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina , Enfermedad de Parkinson , Fosforilación , Unión Proteica , Proteínas Serina-Treonina Quinasas/metabolismo , Transporte de Proteínas
15.
J Cell Biol ; 170(7): 1101-11, 2005 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-16186256

RESUMEN

Macroautophagy is a key pathway for the clearance of aggregate-prone cytosolic proteins. Currently, the only suitable pharmacologic strategy for up-regulating autophagy in mammalian cells is to use rapamycin, which inhibits the mammalian target of rapamycin (mTOR), a negative regulator of autophagy. Here we describe a novel mTOR-independent pathway that regulates autophagy. We show that lithium induces autophagy, and thereby, enhances the clearance of autophagy substrates, like mutant huntingtin and alpha-synucleins. This effect is not mediated by glycogen synthase kinase 3beta inhibition. The autophagy-enhancing properties of lithium were mediated by inhibition of inositol monophosphatase and led to free inositol depletion. This, in turn, decreased myo-inositol-1,4,5-triphosphate (IP3) levels. Our data suggest that the autophagy effect is mediated at the level of (or downstream of) lowered IP3, because it was abrogated by pharmacologic treatments that increased IP3. This novel pharmacologic strategy for autophagy induction is independent of mTOR, and may help treatment of neurodegenerative diseases, like Huntington's disease, where the toxic protein is an autophagy substrate.


Asunto(s)
Autofagia/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Litio/farmacología , Monoéster Fosfórico Hidrolasas/antagonistas & inhibidores , Monoéster Fosfórico Hidrolasas/metabolismo , Animales , Células COS , Línea Celular Tumoral , Chlorocebus aethiops , Humanos , Proteína Huntingtina , Inositol/metabolismo , Mutación , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Quinasas/metabolismo , Sirolimus/farmacología , Serina-Treonina Quinasas TOR , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo
16.
J Neurosci ; 27(14): 3650-62, 2007 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-17409229

RESUMEN

Neurofibrillary tangles (NFTs) are a pathological hallmark of Alzheimer's disease and other tauopathies, but recent studies in a conditional mouse model of tauopathy (rTg4510) have suggested that NFT formation can be dissociated from memory loss and neurodegeneration. This suggests that NFTs are not the major neurotoxic tau species, at least during the early stages of pathogenesis. To identify other neurotoxic tau protein species, we performed biochemical analyses on brain tissues from the rTg4510 mouse model and then correlated the levels of these tau proteins with memory loss. We describe the identification and characterization of two forms of tau multimers (140 and 170 kDa), whose molecular weight suggests an oligomeric aggregate, that accumulate early in the pathogenic cascade in this mouse model. Similar tau multimers were detected in a second mouse model of tauopathy (JNPL3) and in tissue from patients with Alzheimer's disease and FTDP-17 (frontotemporal dementia and parkinsonism linked to chromosome 17). Moreover, levels of the tau multimers correlated consistently with memory loss at various ages in the rTg4510 mouse model. Our findings suggest that accumulation of early-stage aggregated tau species, before the formation of NFT, is associated with the development of functional deficits during the pathogenic progression of tauopathy.


Asunto(s)
Modelos Animales de Enfermedad , Trastornos de la Memoria/metabolismo , Tauopatías/metabolismo , Proteínas tau/metabolismo , Anciano , Anciano de 80 o más Años , Animales , Femenino , Humanos , Masculino , Trastornos de la Memoria/genética , Trastornos de la Memoria/patología , Ratones , Ratones Transgénicos , Persona de Mediana Edad , Tauopatías/genética , Tauopatías/patología , Proteínas tau/biosíntesis , Proteínas tau/genética , Proteínas tau/fisiología
18.
Int J Biochem Cell Biol ; 38(9): 1457-62, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16530457

RESUMEN

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset, autosomal dominant disease caused by the abnormal expansion of a polyalanine tract within the coding region of poly(A) binding protein nuclear 1 (PABPN1). The resultant mutant PABPN1 forms aggregates within the nuclei of skeletal muscle fibres. The mechanism by which the polyalanine expansion mutation in PABN1 causes disease is unclear. However, the mutation is thought to confer a toxic gain-of-function on the protein. Despite controversy over the role of aggregates, it has been consistently shown that agents that reduce aggregate load in cell models of OPMD also reduce levels of cell death. Recently generated animal models of OPMD will help elucidate the mechanism of disease and allow the trial of potential therapeutics. Indeed, administration of known anti-aggregation drugs attenuated muscle weakness in an OPMD mouse model. This suggests that anti-aggregation therapies may be beneficial in OPMD.


Asunto(s)
Distrofia Muscular Oculofaríngea/tratamiento farmacológico , Proteína II de Unión a Poli(A)/genética , Animales , Modelos Animales de Enfermedad , Doxiciclina/uso terapéutico , Humanos , Cuerpos de Inclusión/metabolismo , Distrofia Muscular Oculofaríngea/genética , Péptidos/metabolismo , Estructura Terciaria de Proteína , Trehalosa/uso terapéutico , Repeticiones de Trinucleótidos
19.
Basic Clin Pharmacol Toxicol ; 97(4): 236-7, 2005 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16176559

RESUMEN

Since malnutrition leads to adverse effects of several drugs on haemopoiesis and blood morphology, we tested if malnutrition itself could affect the nucleolar structure and function in rat lymphocytes. We report changes in the proportion of different nucleolar types that were dependent on the severity of feed restriction. The observed changes resemble those seen with cytostatics suggesting a possible link between feed restriction and haemotoxicity.


Asunto(s)
Nucléolo Celular/patología , Linfocitos/patología , Desnutrición , Animales , Privación de Alimentos , Masculino , Microscopía Confocal , Ratas , Ratas Wistar
20.
PLoS One ; 10(3): e0119141, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25763858

RESUMEN

Mutations in glucocerebrosidase (GBA1) cause Gaucher disease and also represent a common risk factor for Parkinson's disease and Dementia with Lewy bodies. Recently, new tool molecules were described which can increase turnover of an artificial substrate 4MUG when incubated with mutant N370S GBA1 from human spleen. Here we show that these compounds exert a similar effect on the wild-type enzyme in a cell-free system. In addition, these tool compounds robustly increase turnover of 4MUG by GBA1 derived from human cortex, despite substantially lower glycosylation of GBA1 in human brain, suggesting that the degree of glycosylation is not important for compound binding. Surprisingly, these tool compounds failed to robustly alter GBA1 turnover of 4MUG in the mouse brain homogenate. Our data raise the possibility that in vivo models with humanized glucocerebrosidase may be needed for efficacy assessments of such small molecules.


Asunto(s)
Encéfalo/enzimología , Glucosilceramidasa/metabolismo , Himecromona/análogos & derivados , Animales , Sistema Libre de Células , Glucosilceramidasa/genética , Glicosilación , Humanos , Himecromona/metabolismo , Ratones
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