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1.
Cell ; 187(12): 2897-2897.e1, 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38848671

RESUMEN

Resmetirom is an oral selective THR-ß agonist conditionally approved for the treatment of patients with noncirrhotic MASH with moderate to advanced fibrosis. Resmetirom restores mitochondrial and hepatic metabolic function; reduces atherogenic lipids; improves hepatic steatosis, inflammation, and fibrosis; and has no significant effect on THR-α. To view this Bench to Bedside, open or download the PDF.


Asunto(s)
Cirrosis Hepática , Piridazinas , Uracilo , Animales , Humanos , Hígado/metabolismo , Hígado/efectos de los fármacos , Cirrosis Hepática/tratamiento farmacológico , Cirrosis Hepática/metabolismo , Cirrosis Hepática/patología , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Piridazinas/uso terapéutico , Uracilo/análogos & derivados
2.
Nat Immunol ; 22(8): 1020-1029, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34312547

RESUMEN

T cell exhaustion is an induced state of dysfunction that arises in response to chronic infection and cancer. Exhausted CD8+ T cells acquire a distinct epigenetic state, but it is not known whether that chromatin landscape is fixed or plastic following the resolution of a chronic infection. Here we show that the epigenetic state of exhaustion is largely irreversible, even after curative therapy. Analysis of chromatin accessibility in HCV- and HIV-specific responses identifies a core epigenetic program of exhaustion in CD8+ T cells, which undergoes only limited remodeling before and after resolution of infection. Moreover, canonical features of exhaustion, including super-enhancers near the genes TOX and HIF1A, remain 'epigenetically scarred.' T cell exhaustion is therefore a conserved epigenetic state that becomes fixed and persists independent of chronic antigen stimulation and inflammation. Therapeutic efforts to reverse T cell exhaustion may require new approaches that increase the epigenetic plasticity of exhausted T cells.


Asunto(s)
Antígenos Virales/inmunología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Hepacivirus/inmunología , Hepatitis C Crónica/inmunología , Memoria Inmunológica/inmunología , 2-Naftilamina/uso terapéutico , Anilidas/uso terapéutico , Antivirales/uso terapéutico , Cromatina/metabolismo , Ciclopropanos/uso terapéutico , Epigénesis Genética/genética , Hepacivirus/efectos de los fármacos , Hepatitis C Crónica/tratamiento farmacológico , Proteínas del Grupo de Alta Movilidad/genética , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Lactamas Macrocíclicas/uso terapéutico , Prolina/análogos & derivados , Prolina/uso terapéutico , Ribavirina/uso terapéutico , Ritonavir/uso terapéutico , Sulfonamidas/uso terapéutico , Uracilo/análogos & derivados , Uracilo/uso terapéutico , Valina/uso terapéutico
3.
Nat Immunol ; 20(9): 1244-1255, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31431722

RESUMEN

Mucosal-associated invariant T cells (MAIT cells) recognize the microbial metabolite 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil (5-OP-RU) presented by the MHC class Ib molecule, MR1. MAIT cells acquire effector functions during thymic development, but the mechanisms involved are unclear. Here we used single-cell RNA-sequencing to characterize the developmental path of 5-OP-RU-specific thymocytes. In addition to the known MAIT1 and MAIT17 effector subsets selected on bone-marrow-derived hematopoietic cells, we identified 5-OP-RU-specific thymocytes that were selected on thymic epithelial cells and differentiated into CD44- naive T cells. MAIT cell positive selection required signaling through the adapter, SAP, that controlled the expression of the transcription factor, ZBTB16. Pseudotemporal ordering of single cells revealed transcriptional trajectories of 5-OP-RU-specific thymocytes selected on either thymic epithelial cells or hematopoietic cells. The resulting model illustrates T cell lineage decisions.


Asunto(s)
Linaje de la Célula/inmunología , Células T Invariantes Asociadas a Mucosa/citología , Células T Invariantes Asociadas a Mucosa/inmunología , Ribitol/análogos & derivados , Timocitos/citología , Timocitos/inmunología , Uracilo/análogos & derivados , Animales , Secuencia de Bases , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Antígenos de Histocompatibilidad Clase I/metabolismo , Receptores de Hialuranos/metabolismo , Activación de Linfocitos/inmunología , Ratones , Ratones Noqueados , Antígenos de Histocompatibilidad Menor/metabolismo , Proteína de la Leucemia Promielocítica con Dedos de Zinc/biosíntesis , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Ribitol/inmunología , Análisis de Secuencia de ARN , Familia de Moléculas Señalizadoras de la Activación Linfocitaria/metabolismo , Timo/citología , Timo/inmunología , Uracilo/inmunología
4.
N Engl J Med ; 390(6): 497-509, 2024 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-38324483

RESUMEN

BACKGROUND: Nonalcoholic steatohepatitis (NASH) is a progressive liver disease with no approved treatment. Resmetirom is an oral, liver-directed, thyroid hormone receptor beta-selective agonist in development for the treatment of NASH with liver fibrosis. METHODS: We are conducting an ongoing phase 3 trial involving adults with biopsy-confirmed NASH and a fibrosis stage of F1B, F2, or F3 (stages range from F0 [no fibrosis] to F4 [cirrhosis]). Patients were randomly assigned in a 1:1:1 ratio to receive once-daily resmetirom at a dose of 80 mg or 100 mg or placebo. The two primary end points at week 52 were NASH resolution (including a reduction in the nonalcoholic fatty liver disease [NAFLD] activity score by ≥2 points; scores range from 0 to 8, with higher scores indicating more severe disease) with no worsening of fibrosis, and an improvement (reduction) in fibrosis by at least one stage with no worsening of the NAFLD activity score. RESULTS: Overall, 966 patients formed the primary analysis population (322 in the 80-mg resmetirom group, 323 in the 100-mg resmetirom group, and 321 in the placebo group). NASH resolution with no worsening of fibrosis was achieved in 25.9% of the patients in the 80-mg resmetirom group and 29.9% of those in the 100-mg resmetirom group, as compared with 9.7% of those in the placebo group (P<0.001 for both comparisons with placebo). Fibrosis improvement by at least one stage with no worsening of the NAFLD activity score was achieved in 24.2% of the patients in the 80-mg resmetirom group and 25.9% of those in the 100-mg resmetirom group, as compared with 14.2% of those in the placebo group (P<0.001 for both comparisons with placebo). The change in low-density lipoprotein cholesterol levels from baseline to week 24 was -13.6% in the 80-mg resmetirom group and -16.3% in the 100-mg resmetirom group, as compared with 0.1% in the placebo group (P<0.001 for both comparisons with placebo). Diarrhea and nausea were more frequent with resmetirom than with placebo. The incidence of serious adverse events was similar across trial groups: 10.9% in the 80-mg resmetirom group, 12.7% in the 100-mg resmetirom group, and 11.5% in the placebo group. CONCLUSIONS: Both the 80-mg dose and the 100-mg dose of resmetirom were superior to placebo with respect to NASH resolution and improvement in liver fibrosis by at least one stage. (Funded by Madrigal Pharmaceuticals; MAESTRO-NASH ClinicalTrials.gov number, NCT03900429.).


Asunto(s)
Cirrosis Hepática , Enfermedad del Hígado Graso no Alcohólico , Piridazinas , Uracilo , Adulto , Humanos , Método Doble Ciego , Hígado/diagnóstico por imagen , Hígado/efectos de los fármacos , Hígado/patología , Cirrosis Hepática/tratamiento farmacológico , Cirrosis Hepática/etiología , Cirrosis Hepática/patología , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Enfermedad del Hígado Graso no Alcohólico/patología , Piridazinas/uso terapéutico , Resultado del Tratamiento , Uracilo/análogos & derivados , Receptores beta de Hormona Tiroidea/agonistas , Biopsia , Relación Dosis-Respuesta a Droga
5.
N Engl J Med ; 390(20): 1849-1861, 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38739079

RESUMEN

BACKGROUND: One of the major determinants of exercise intolerance and limiting symptoms among patients with obstructive hypertrophic cardiomyopathy (HCM) is an elevated intracardiac pressure resulting from left ventricular outflow tract obstruction. Aficamten is an oral selective cardiac myosin inhibitor that reduces left ventricular outflow tract gradients by mitigating cardiac hypercontractility. METHODS: In this phase 3, double-blind trial, we randomly assigned adults with symptomatic obstructive HCM to receive aficamten (starting dose, 5 mg; maximum dose, 20 mg) or placebo for 24 weeks, with dose adjustment based on echocardiography results. The primary end point was the change from baseline to week 24 in the peak oxygen uptake as assessed by cardiopulmonary exercise testing. The 10 prespecified secondary end points (tested hierarchically) were change in the Kansas City Cardiomyopathy Questionnaire clinical summary score (KCCQ-CSS), improvement in the New York Heart Association (NYHA) functional class, change in the pressure gradient after the Valsalva maneuver, occurrence of a gradient of less than 30 mm Hg after the Valsalva maneuver, and duration of eligibility for septal reduction therapy (all assessed at week 24); change in the KCCQ-CSS, improvement in the NYHA functional class, change in the pressure gradient after the Valsalva maneuver, and occurrence of a gradient of less than 30 mm Hg after the Valsalva maneuver (all assessed at week 12); and change in the total workload as assessed by cardiopulmonary exercise testing at week 24. RESULTS: A total of 282 patients underwent randomization: 142 to the aficamten group and 140 to the placebo group. The mean age was 59.1 years, 59.2% were men, the baseline mean resting left ventricular outflow tract gradient was 55.1 mm Hg, and the baseline mean left ventricular ejection fraction was 74.8%. At 24 weeks, the mean change in the peak oxygen uptake was 1.8 ml per kilogram per minute (95% confidence interval [CI], 1.2 to 2.3) in the aficamten group and 0.0 ml per kilogram per minute (95% CI, -0.5 to 0.5) in the placebo group (least-squares mean between-group difference, 1.7 ml per kilogram per minute; 95% CI, 1.0 to 2.4; P<0.001). The results for all 10 secondary end points were significantly improved with aficamten as compared with placebo. The incidence of adverse events appeared to be similar in the two groups. CONCLUSIONS: Among patients with symptomatic obstructive HCM, treatment with aficamten resulted in a significantly greater improvement in peak oxygen uptake than placebo. (Funded by Cytokinetics; SEQUOIA-HCM ClinicalTrials.gov number, NCT05186818.).


Asunto(s)
Cardiomiopatía Hipertrófica , Fármacos Cardiovasculares , Prueba de Esfuerzo , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Bencilaminas , Miosinas Cardíacas/antagonistas & inhibidores , Cardiomiopatía Hipertrófica/tratamiento farmacológico , Cardiomiopatía Hipertrófica/fisiopatología , Método Doble Ciego , Tolerancia al Ejercicio/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Uracilo/análogos & derivados , Maniobra de Valsalva , Obstrucción del Flujo Ventricular Externo/tratamiento farmacológico , Obstrucción del Flujo Ventricular Externo/fisiopatología , Obstrucción del Flujo Ventricular Externo/etiología , Fármacos Cardiovasculares/farmacología , Fármacos Cardiovasculares/uso terapéutico , Contracción Miocárdica/efectos de los fármacos , Contracción Miocárdica/fisiología , Administración Oral
6.
Cell ; 150(5): 909-21, 2012 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-22939620

RESUMEN

Some Ts in nuclear DNA of trypanosomes and Leishmania are hydroxylated and glucosylated to yield base J (ß-D-glucosyl-hydroxymethyluracil). In Leishmania, about 99% of J is located in telomeric repeats. We show here that most of the remaining J is located at chromosome-internal RNA polymerase II termination sites. This internal J and telomeric J can be reduced by a knockout of J-binding protein 2 (JBP2), an enzyme involved in the first step of J biosynthesis. J levels are further reduced by growing Leishmania JBP2 knockout cells in BrdU-containing medium, resulting in cell death. The loss of internal J in JBP2 knockout cells is accompanied by massive readthrough at RNA polymerase II termination sites. The readthrough varies between transcription units but may extend over 100 kb. We conclude that J is required for proper transcription termination and infer that the absence of internal J kills Leishmania by massive readthrough of transcriptional stops.


Asunto(s)
Glucósidos/metabolismo , Leishmania/genética , Leishmania/metabolismo , Transcripción Genética , Uracilo/análogos & derivados , Técnicas de Inactivación de Genes , ARN Polimerasa II/metabolismo , ARN Bicatenario/metabolismo , Uracilo/metabolismo
7.
Proc Natl Acad Sci U S A ; 121(8): e2314914121, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38346202

RESUMEN

Mavacamten is a FDA-approved small-molecule therapeutic designed to regulate cardiac function at the sarcomere level by selectively but reversibly inhibiting the enzymatic activity of myosin. It shifts myosin toward ordered off states close to the thick filament backbone. It remains elusive whether these myosin heads in the off state(s) can be recruited in response to physiological stimuli when required to boost cardiac output. We show that cardiac myosins stabilized in these off state(s) by mavacamten are recruitable by 1) Ca2+, 2) increased chronotropy [heart rate (HR)], 3) stretch, and 4) ß-adrenergic (ß-AR) stimulation, all known physiological inotropic interventions. At the molecular level, we show that Ca2+ increases myosin ATPase activity by shifting mavacamten-stabilized myosin heads from the inactive super-relaxed state to the active disordered relaxed state. At the myofilament level, both Ca2+ and passive lengthening can shift mavacamten-ordered off myosin heads from positions close to the thick filament backbone to disordered on states closer to the thin filaments. In isolated rat cardiomyocytes, increased stimulation rates enhanced shortening fraction in mavacamten-treated cells. This observation was confirmed in vivo in telemetered rats, where left-ventricular dP/dtmax, an index of inotropy, increased with HR in mavacamten-treated animals. Finally, we show that ß-AR stimulation in vivo increases left-ventricular function and stroke volume in the setting of mavacamten. Our data demonstrate that the mavacamten-promoted off states of myosin in the thick filament are at least partially activable, thus preserving cardiac reserve mechanisms.


Asunto(s)
Miocitos Cardíacos , Miosinas , Uracilo/análogos & derivados , Animales , Ratas , Bencilaminas/farmacología , Contracción Muscular
8.
Proc Natl Acad Sci U S A ; 121(9): e2311883121, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38386705

RESUMEN

Heart muscle has the unique property that it can never rest; all cardiomyocytes contract with each heartbeat which requires a complex control mechanism to regulate cardiac output to physiological requirements. Changes in calcium concentration regulate the thin filament activation. A separate but linked mechanism regulates the thick filament activation, which frees sufficient myosin heads to bind the thin filament, thereby producing the required force. Thick filaments contain additional nonmyosin proteins, myosin-binding protein C and titin, the latter being the protein that transmits applied tension to the thick filament. How these three proteins interact to control thick filament activation is poorly understood. Here, we show using 3-D image reconstruction of frozen-hydrated human cardiac muscle myofibrils lacking exogenous drugs that the thick filament is structured to provide three levels of myosin activation corresponding to the three crowns of myosin heads in each 429Å repeat. In one crown, the myosin heads are almost completely activated and disordered. In another crown, many myosin heads are inactive, ordered into a structure called the interacting heads motif. At the third crown, the myosin heads are ordered into the interacting heads motif, but the stability of that motif is affected by myosin-binding protein C. We think that this hierarchy of control explains many of the effects of length-dependent activation as well as stretch activation in cardiac muscle control.


Asunto(s)
Bencilaminas , Miocardio , Sarcómeros , Uracilo/análogos & derivados , Humanos , Miofibrillas , Miocitos Cardíacos , Miosinas
9.
Proc Natl Acad Sci U S A ; 121(25): e2404457121, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38865275

RESUMEN

The fat mass and obesity-associated fatso (FTO) protein is a member of the Alkb family of dioxygenases and catalyzes oxidative demethylation of N6-methyladenosine (m6A), N1-methyladenosine (m1A), 3-methylthymine (m3T), and 3-methyluracil (m3U) in single-stranded nucleic acids. It is well established that the catalytic activity of FTO proceeds via two coupled reactions. The first reaction involves decarboxylation of alpha-ketoglutarate (αKG) and formation of an oxyferryl species. In the second reaction, the oxyferryl intermediate oxidizes the methylated nucleic acid to reestablish Fe(II) and the canonical base. However, it remains unclear how binding of the nucleic acid activates the αKG decarboxylation reaction and why FTO demethylates different methyl modifications at different rates. Here, we investigate the interaction of FTO with 5-mer DNA oligos incorporating the m6A, m1A, or m3T modifications using solution NMR, molecular dynamics (MD) simulations, and enzymatic assays. We show that binding of the nucleic acid to FTO activates a two-state conformational equilibrium in the αKG cosubstrate that modulates the O2 accessibility of the Fe(II) catalyst. Notably, the substrates that provide better stabilization to the αKG conformation in which Fe(II) is exposed to O2 are demethylated more efficiently by FTO. These results indicate that i) binding of the methylated nucleic acid is required to expose the catalytic metal to O2 and activate the αKG decarboxylation reaction, and ii) the measured turnover of the demethylation reaction (which is an ensemble average over the entire sample) depends on the ability of the methylated base to favor the Fe(II) state accessible to O2.


Asunto(s)
Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato , Hierro , Ácidos Cetoglutáricos , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/metabolismo , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/química , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/genética , Ácidos Cetoglutáricos/metabolismo , Ácidos Cetoglutáricos/química , Hierro/metabolismo , Hierro/química , Humanos , Especificidad por Sustrato , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/química , Conformación Proteica , Uracilo/metabolismo , Uracilo/análogos & derivados , Uracilo/química , Simulación de Dinámica Molecular , Timina/análogos & derivados
10.
RNA ; 30(7): 901-919, 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38670632

RESUMEN

A key to understanding the roles of RNA in regulating gene expression is knowing their structures in vivo. One way to obtain this information is through probing the structures of RNA with chemicals. To probe RNA structure directly in cells, membrane-permeable reagents that modify the Watson-Crick (WC) face of unpaired nucleotides can be used. Although dimethyl sulfate (DMS) has led to substantial insight into RNA structure, it has limited nucleotide specificity in vivo, with WC face reactivity only at adenine (A) and cytosine (C) at neutral pH. The reagent 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) was recently shown to modify the WC face of guanine (G) and uracil (U). Although useful at lower concentrations in experiments that measure chemical modifications by reverse transcription (RT) stops, at higher concentrations necessary for detection by mutational profiling (MaP), EDC treatment leads to degradation of RNA. Here, we demonstrate EDC-stimulated degradation of RNA in Gram-negative and Gram-positive bacteria. In an attempt to overcome these limitations, we developed a new carbodiimide reagent, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide methiodide (ETC), which we show specifically modifies unpaired Gs and Us in vivo without substantial degradation of RNA. We establish ETC as a probe for MaP and optimize the RT conditions and computational analysis in Escherichia coli Importantly, we demonstrate the utility of ETC as a probe for improving RNA structure prediction both alone and with DMS.


Asunto(s)
Guanina , Conformación de Ácido Nucleico , Ésteres del Ácido Sulfúrico , Uracilo , Ésteres del Ácido Sulfúrico/química , Uracilo/química , Uracilo/análogos & derivados , Uracilo/metabolismo , Guanina/química , Guanina/metabolismo , ARN/química , ARN/genética , Escherichia coli/genética , Escherichia coli/efectos de los fármacos , Carbodiimidas/química , ARN Bacteriano/química , ARN Bacteriano/genética , Estabilidad del ARN , Indicadores y Reactivos/química
11.
J Biol Chem ; 300(5): 107229, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38537698

RESUMEN

Mucosal-associated invariant T (MAIT) cells can elicit immune responses against riboflavin-based antigens presented by the evolutionary conserved MHC class I related protein, MR1. While we have an understanding of the structural basis of human MAIT cell receptor (TCR) recognition of human MR1 presenting a variety of ligands, how the semi-invariant mouse MAIT TCR binds mouse MR1-ligand remains unknown. Here, we determine the crystal structures of 2 mouse TRAV1-TRBV13-2+ MAIT TCR-MR1-5-OP-RU ternary complexes, whose TCRs differ only in the composition of their CDR3ß loops. These mouse MAIT TCRs mediate high affinity interactions with mouse MR1-5-OP-RU and cross-recognize human MR1-5-OP-RU. Similarly, a human MAIT TCR could bind mouse MR1-5-OP-RU with high affinity. This cross-species recognition indicates the evolutionary conserved nature of this MAIT TCR-MR1 axis. Comparing crystal structures of the mouse versus human MAIT TCR-MR1-5-OP-RU complexes provides structural insight into the conserved nature of this MAIT TCR-MR1 interaction and conserved specificity for the microbial antigens, whereby key germline-encoded interactions required for MAIT activation are maintained. This is an important consideration for the development of MAIT cell-based therapeutics that will rely on preclinical mouse models of disease.


Asunto(s)
Antígenos de Histocompatibilidad Clase I , Antígenos de Histocompatibilidad Menor , Células T Invariantes Asociadas a Mucosa , Ribitol , Animales , Antígenos de Histocompatibilidad Clase I/metabolismo , Antígenos de Histocompatibilidad Clase I/inmunología , Antígenos de Histocompatibilidad Clase I/química , Antígenos de Histocompatibilidad Menor/metabolismo , Antígenos de Histocompatibilidad Menor/genética , Antígenos de Histocompatibilidad Menor/inmunología , Antígenos de Histocompatibilidad Menor/química , Ratones , Células T Invariantes Asociadas a Mucosa/inmunología , Células T Invariantes Asociadas a Mucosa/metabolismo , Humanos , Ribitol/análogos & derivados , Ribitol/metabolismo , Ribitol/química , Uracilo/análogos & derivados , Uracilo/metabolismo , Uracilo/química , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores de Antígenos de Linfocitos T/inmunología , Cristalografía por Rayos X
12.
J Biol Chem ; 300(1): 105565, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38103642

RESUMEN

The biochemical SRX (super-relaxed) state of myosin has been defined as a low ATPase activity state. This state can conserve energy when the myosin is not recruited for muscle contraction. The SRX state has been correlated with a structurally defined ordered (versus disordered) state of muscle thick filaments. The two states may be linked via a common interacting head motif (IHM) where the two heads of heavy meromyosin (HMM), or myosin, fold back onto each other and form additional contacts with S2 and the thick filament. Experimental observations of the SRX, IHM, and the ordered form of thick filaments, however, do not always agree, and result in a series of unresolved paradoxes. To address these paradoxes, we have reexamined the biochemical measurements of the SRX state for porcine cardiac HMM. In our hands, the commonly employed mantATP displacement assay was unable to quantify the population of the SRX state with all data fitting very well by a single exponential. We further show that mavacamten inhibits the basal ATPases of both porcine ventricle HMM and S1 (Ki, 0.32 and 1.76 µM respectively) while dATP activates HMM cooperatively without any evidence of an SRX state. A combination of our experimental observations and theories suggests that the displacement of mantATP in purified proteins is not a reliable assay to quantify the SRX population. This means that while the structurally defined IHM and ordered thick filaments clearly exist, great care must be employed when using the mantATP displacement assay.


Asunto(s)
Adenosina Trifosfato , Pruebas de Enzimas , Miosina Tipo IIA no Muscular , Porcinos , ortoaminobenzoatos , Animales , Adenosina Trifosfatasas/antagonistas & inhibidores , Adenosina Trifosfatasas/metabolismo , Adenosina Trifosfato/análogos & derivados , Adenosina Trifosfato/metabolismo , Secuencias de Aminoácidos , Bencilaminas/farmacología , Pruebas de Enzimas/métodos , Pruebas de Enzimas/normas , Ventrículos Cardíacos/efectos de los fármacos , Ventrículos Cardíacos/enzimología , Ventrículos Cardíacos/metabolismo , Contracción Miocárdica , Subfragmentos de Miosina/química , Subfragmentos de Miosina/metabolismo , Miosina Tipo IIA no Muscular/química , Miosina Tipo IIA no Muscular/metabolismo , ortoaminobenzoatos/metabolismo , Uracilo/análogos & derivados , Uracilo/farmacología
13.
Circulation ; 149(7): 498-509, 2024 02 13.
Artículo en Inglés | MEDLINE | ID: mdl-37961906

RESUMEN

BACKGROUND: Compared with men, women with hypertrophic cardiomyopathy (HCM) have a higher incidence of heart failure and worse outcomes. We investigated baseline clinical and echocardiographic characteristics and response to mavacamten among women compared with men in the EXPLORER-HCM study (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy). METHODS: A prespecified post hoc analysis of sex from the blinded, randomized EXPLORER-HCM trial of mavacamten versus placebo in symptomatic patients with obstructive HCM was performed. Baseline characteristics were compared with t tests for continuous variables (expressed as mean values) and χ2 tests for categorical variables. Prespecified primary, secondary, and exploratory end points and echocardiographic measurements from baseline to end of treatment (week 30) were analyzed with ANCOVA for continuous end points and a generalized linear model with binomial distribution for binary end points, with adjustment for each outcome's baseline value, New York Heart Association class, ß-blocker use, and ergometer type. RESULTS: At baseline, women (n=102) were older (62 years versus 56 years; P<0.0001), had lower peak oxygen consumption (16.7 mL·kg-1·min-1 versus 21.3 mL·kg-1·min-1; P<0.0001), were more likely to be assigned New York Heart Association class III (42% versus 17%; P<0.0001), had worse health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 64 versus 75; P<0.0001), and had higher baseline plasma NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels (1704 ng/L versus 990 ng/L; P=0.004) than men (n=149). After 30 weeks of mavacamten treatment, similar improvements were observed in women and men in the primary composite end point (percentage difference on mavacamten versus placebo, 22% versus 19%, respectively; P=0.759) and in the secondary end points of change in postexercise left ventricular outflow tract gradient (-42.4 mm Hg versus -33.6 mm Hg; P=0.348), change in peak oxygen consumption (1.2 mL·kg-1·min-1 versus 1.6 mL·kg-1·min-1; P=0.633), and percentage achieving ≥1 New York Heart Association class improvement (41% versus 28%; P=0.254). However, women had greater improvement in health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 14.8 versus 6.1; P=0.026) and in the exploratory end point of NT-proBNP levels (-1322 ng/L versus -649 ng/L; P=0.0008). CONCLUSIONS: Although at baseline women with symptomatic obstructive HCM enrolled in EXPLORER-HCM were older and had worse heart failure and health status than men, treatment with mavacamten resulted in similar improvements in the primary and most secondary EXPLORER-HCM end points and greater improvements in health status and NT-proBNP. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03470545.


Asunto(s)
Bencilaminas , Cardiomiopatía Hipertrófica , Uracilo , Adulto , Femenino , Humanos , Masculino , Bencilaminas/uso terapéutico , Cardiomiopatía Hipertrófica/tratamiento farmacológico , Insuficiencia Cardíaca , Uracilo/uso terapéutico , Uracilo/análogos & derivados , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores Sexuales
14.
Br J Cancer ; 131(8): 1290-1297, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39244627

RESUMEN

BACKGROUND: The efficacy of FOLFIRI plus an antiangiogenesis biologic agent as 2nd line therapy for metastatic colorectal adenocarcinoma is limited. TAS-102 is a novel oral antimetabolite with a distinct mechanism of action from fluoropyrimidines. We evaluated the antitumour efficacy of TAS-102, irinotecan and bevacizumab in patients with pre-treated, advanced colorectal adenocarcinoma in a multicenter, phase II, single-arm study. METHODS: Patients with advanced colorectal adenocarcinoma who had progressed after oxaliplatin and fluoropyrimidine and were eligible for treatment with bevacizumab were treated with irinotecan, bevacizumab, and TAS-102 in 28-day cycles. The primary endpoint was progression-free survival (PFS). RESULTS: We enrolled 35 evaluable patients. The study was positive. The median PFS was 7.9 (90% CI 6.2-11.8) months (vs. 6 months in historical control, p = 0.018). The median overall survival was 16.5 (90% CI 9.8-17.5) months. Sixty-seven per cent of patients experienced grade 3 or higher treatment-related adverse events. The most common toxicities were hematological (neutropenia) and gastrointestinal (diarrhoea, nausea, and vomiting). CONCLUSIONS: Irinotecan, TAS-102 and bevacizumab is an active 2nd line therapy for patients with metastatic colorectal adenocarcinoma. Neutropenia is common and can affect dose density/intensity mandating use of G-CSF. A randomized study versus standard-of-care therapy is warranted. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT04109924.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica , Bevacizumab , Neoplasias Colorrectales , Combinación de Medicamentos , Irinotecán , Pirrolidinas , Timina , Trifluridina , Uracilo , Humanos , Bevacizumab/administración & dosificación , Bevacizumab/uso terapéutico , Bevacizumab/efectos adversos , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Irinotecán/administración & dosificación , Irinotecán/uso terapéutico , Masculino , Trifluridina/administración & dosificación , Trifluridina/uso terapéutico , Trifluridina/efectos adversos , Femenino , Persona de Mediana Edad , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Anciano , Adulto , Uracilo/análogos & derivados , Uracilo/uso terapéutico , Uracilo/administración & dosificación , Pirrolidinas/uso terapéutico , Pirrolidinas/administración & dosificación , Pirrolidinas/efectos adversos , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/patología , Adenocarcinoma/secundario , Supervivencia sin Progresión , Metástasis de la Neoplasia , Anciano de 80 o más Años
15.
Biochem Biophys Res Commun ; 734: 150742, 2024 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-39353359

RESUMEN

Alcoholic steatohepatitis (ASH) represents a critical stage in alcoholic liver disease (ALD), which significantly increases the risk of developing alcoholic hepatitis and cirrhosis. Currently, corticosteroids and alcohol abstinence remain the only available strategy to prevent or reverse ASH progression with no FDA approved drug therapy till date. Given the notable pathological similarities between ASH and metabolic dysfunction-associated steatohepatitis (MASH), repurposing drugs approved for MASH presents an attractive therapeutic approach to treat ASH. In this context, we evaluated the efficacy of Resmetirom, a recently approved drug for MASH, in a mouse model of ASH. Our findings demonstrate that Resmetirom, a liver-specific thyroid hormone analog, not only reduces hepatic steatosis but also markedly alleviates liver injury, oxidative stress, and inflammation associated with ASH. In summary, this study provides a proof-of-concept for the potential use of MASH drugs in treating ASH and establishes a foundation for future testing and clinical trials of Resmetirom, in patients with ASH.


Asunto(s)
Hígado Graso Alcohólico , Hígado , Ratones Endogámicos C57BL , Receptores beta de Hormona Tiroidea , Animales , Hígado Graso Alcohólico/tratamiento farmacológico , Hígado Graso Alcohólico/metabolismo , Hígado Graso Alcohólico/patología , Ratones , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Receptores beta de Hormona Tiroidea/agonistas , Receptores beta de Hormona Tiroidea/metabolismo , Receptores beta de Hormona Tiroidea/genética , Masculino , Estrés Oxidativo/efectos de los fármacos , Modelos Animales de Enfermedad , Piridazinas , Uracilo/análogos & derivados
16.
Am Heart J ; 277: 138-141, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39242133

RESUMEN

INTRODUCTION: We have previously reported that genetically positive patients have a more profound early decrease in provocable left ventricular outflow tract gradient compared to genetically negative patients utilizing mavacamten in the first 12 weeks of therapy. METHODS AND RESULTS: In this current analysis, we found that genetically positive patients have less favorable remodeling as measured by left ventricular wall thickness regression when evaluated long-term as compared to genetically negative patients, despite an overall better early response to mavacamten. The majority of genetically positive patients were maintained on only 2.5 mg of mavacamten due to early robust response. CONCLUSION: We hypothesize that this lower dosing attenuated the long-term benefit of mavacamten in genetically positive patients. We believe that the long-term benefit of mavacamten on positive cardiac remodeling is dose-dependent and not solely related to the magnitude of left ventricular outflow gradient decrease.


Asunto(s)
Remodelación Ventricular , Humanos , Remodelación Ventricular/efectos de los fármacos , Remodelación Ventricular/genética , Masculino , Femenino , Estudios de Seguimiento , Persona de Mediana Edad , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Resultado del Tratamiento , Factores de Tiempo , Bencilaminas , Uracilo/análogos & derivados
17.
J Transl Med ; 22(1): 379, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38650006

RESUMEN

BACKGROUND: TAS-102 (Lonsurf®) is an oral fluoropyrimidine consisting of a combination of trifluridine (a thymidine analog) and tipiracil (a thymidine phosphorylation inhibitor). The drug is effective in metastatic colorectal cancer (mCRC) patients refractory to fluorouracil, irinotecan and oxaliplatin. This study is a real-world analysis, investigating the interplay of genotype/phenotype in relation to TAS-102 sensitivity. METHODS: Forty-seven consecutive mCRC patients were treated with TAS-102 at the National Cancer Institute of Naples from March 2019 to March 2021, at a dosage of 35 mg/m2, twice a day, in cycles of 28 days (from day 1 to 5 and from day 8 to 12). Clinical-pathological parameters were described. Activity was evaluated with RECIST criteria (v1.1) and toxicity with NCI-CTC (v5.0). Survival was depicted through the Kaplan-Meyer curves. Genetic features of patients were evaluated with Next Generation Sequencing (NGS) through the Illumina NovaSeq 6000 platform and TruSigt™Oncology 500 kit. RESULTS: Median age of patients was 65 years (range: 46-77). Forty-one patients had 2 or more metastatic sites and 38 patients underwent to more than 2 previous lines of therapies. ECOG (Eastern Cooperative Oncology Group) Performance Status (PS) was 2 in 19 patients. The median number of TAS-102 cycles was 4 (range: 2-12). The most frequent toxic event was neutropenia (G3/G4 in 16 patients). There were no severe (> 3) non-haematological toxicities or treatment-related deaths. Twenty-six patients experienced progressive disease (PD), 21 stable disease (SD). Three patients with long-lasting disease control (DC: complete, partial responses or stable disease) shared an FGFR4 (p.Gly388Arg) mutation. Patients experiencing DC had more frequently a low tumour growth rate (P = 0.0306) and an FGFR4 p.G388R variant (P < 0.0001). The FGFR4 Arg388 genotype was associated with better survival (median: 6.4 months) compared to the Gly388 genotype (median: 4 months); the HR was 0.25 (95% CI 0.12- 0.51; P = 0.0001 at Log-Rank test). CONCLUSIONS: This phenotype/genotype investigation suggests that the FGFR4 p.G388R variant may serve as a new marker for identifying patients who are responsive to TAS-102. A mechanistic hypothesis is proposed to interpret these findings.


Asunto(s)
Neoplasias Colorrectales , Combinación de Medicamentos , Metástasis de la Neoplasia , Pirrolidinas , Receptor Tipo 4 de Factor de Crecimiento de Fibroblastos , Timina , Trifluridina , Uracilo , Humanos , Trifluridina/uso terapéutico , Trifluridina/efectos adversos , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Pirrolidinas/uso terapéutico , Masculino , Femenino , Uracilo/análogos & derivados , Uracilo/uso terapéutico , Uracilo/efectos adversos , Persona de Mediana Edad , Anciano , Receptor Tipo 4 de Factor de Crecimiento de Fibroblastos/genética , Polimorfismo de Nucleótido Simple/genética
18.
J Card Fail ; 30(9): 1136-1153, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38777216

RESUMEN

For many years, treatment of hypertrophic cardiomyopathy (HCM) has focused on non-disease-specific therapies. Cardiac myosin modulators (ie, mavacamten and aficamten) reduce the pathologic actin-myosin interactions that are characteristic of HCM, leading to improved cardiac energetics and reduction in hypercontractility. Several recently published randomized clinical trials have demonstrated that mavacamten improves exercise capacity, left ventricular outflow tract obstruction and symptoms in patients with obstructive HCM and may delay the need for septal-reduction therapy. Long-term data in real-world populations will be needed to fully assess the safety and efficacy of mavacamten. Importantly, HCM is a complex and heterogeneous disease, and not all patients will respond to mavacamten; therefore, careful patient selection and shared decision making will be necessary in guiding the use of mavacamten in obstructive HCM.


Asunto(s)
Cardiomiopatía Hipertrófica , Manejo de la Enfermedad , Humanos , Cardiomiopatía Hipertrófica/terapia , Cardiomiopatía Hipertrófica/fisiopatología , Bencilaminas/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos , Resultado del Tratamiento , Uracilo/análogos & derivados
19.
Heart Fail Rev ; 29(2): 479-496, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38112937

RESUMEN

Hypertrophic cardiomyopathy (HCM) is the most common heritable myocardial disorder worldwide. Current pharmacological treatment options are limited. Mavacamten, a first-in-class cardiac myosin inhibitor, targets the main underlying pathology of HCM. We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of Mavacamten in patients with HCM. PRISMA flow chart was utilized using PubMed, SCOPUS, and Cochrane databases for all up-to-date studies using pre-defined keywords. Pre-specified efficacy outcomes comprised several parameters, including an improvement in peak oxygen consumption (pVO2) and ≥ 1 NYHA class, the need for septal reduction therapy (SRT), change from baseline in Kansas City Cardiomyopathy Questionnaire (KCCQ), changes in biochemical markers and LVEF, along with peak left ventricular outflow tract gradient at rest and after Valsalva maneuver. Safety outcomes included morbidity and serious adverse events. This systematic review included five studies, four RCTs and one non-randomized control trial comprised a total of 524 (Mavacamten [273, 54.3%] vs placebo [230, 45.7%] adult (≥ 18 years) patients with a mean age of 56 years. The study. comprised patients with Caucasian and Chinese ethnicity and patients with obstructive (oHCM) and non-obstructive (nHCM) HCM. Most baseline characteristics were similar between the treatment and placebo groups. Mavacamten showed a statistically significant increase in the frequency of the primary composite endpoint (RR = 1.92, 95% CI [1.28, 2.88]), ≥ 1 NYHA class improvement (RR = 2.10, 95% CI [1.66, 2.67]), a significant decrease in LVEF, peak left ventricular outflow tract gradient at rest and after Valsalva maneuver. Mavacamten also showed a significant reduction in SRT rates (RR = 0.29, 95% CI [0.21, 0.40], p < 0.00001), KCCQ clinical summary scores (MD = 8.08, 95% CI [4.80, 11.37], P < 0.00001) troponin levels and N-terminal pro-B-type natriuretic peptide levels. However, there was no statistically significant difference between Mavacamten and placebo regarding the change from baseline peak oxygen consumption. Mavacamten use resulted in a small increase in adverse events but no statistically significant increment in serious adverse events. Our study showed that Mavacamten is a safe and effective treatment option for Caucasian and Chinese patients with HCM on the short-term. Further research is needed to explore the long-term safety and efficacy of Mavacamten with HCM. In addition, adequately powered studies including patients with nHCM is needed to ascertain befits of Mavacamten in those patients.


Asunto(s)
Cardiomiopatía Hipertrófica , Humanos , Cardiomiopatía Hipertrófica/tratamiento farmacológico , Cardiomiopatía Hipertrófica/fisiopatología , Resultado del Tratamiento , Uracilo/análogos & derivados , Uracilo/uso terapéutico , Uracilo/efectos adversos , Función Ventricular Izquierda/efectos de los fármacos , Función Ventricular Izquierda/fisiología , Bencilaminas
20.
Invest New Drugs ; 42(4): 454-461, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38990451

RESUMEN

PURPOSE: This phase I trial is to determine the recommended dose of the TAS-102, irinotecan plus bevacizumab regimen and assess its safety and efficacy in patients with metastatic colorectal cancer refractory to fluoropyrimidine and oxaliplatin treatment. METHODS: A 3 + 3 designed dose escalation was performed. Patients were administered TAS-102 (30-35 mg/m2 twice daily on days 1-5) and irinotecan (150-165 mg/m2 on day 1) combined with a fixed dose of bevacizumab (5 mg/kg on day 1) every two weeks. The primary endpoint was the determination of the recommended phase II dose. RESULTS: Eighteen patients were enrolled: 6 at the Level 1 (TAS-102 30 mg/m2 twice daily, irinotecan 150 mg/m2 plus bevacizumab 5 mg/kg), six at the Level 2 (TAS-102 35 mg/m2 twice daily, irinotecan 150 mg/m2 plus bevacizumab 5 mg/kg), and six at the Level 3 (TAS-102 30 mg/m2 twice daily, irinotecan 165 mg/m2 plus bevacizumab 5 mg/kg). Five dose-limiting toxicities occurred: one observed at Level 1 (thrombocytopenia), two at Level 2 (neutropenia and diarrhea), and two at Level 3 (fatigue and neutropenia). The RP2D was established as TAS-102 30 mg/m2 twice daily and irinotecan 150 mg/m2 plus bevacizumab 5 mg/kg. The most frequent grade 3/4 treatment-related adverse events were neutropenia (33.3%), diarrhea (16.7%), and thrombocytopenia (11.1%). No treatment-related death occurred. Two patients (11.1%) experienced partial responses and 14 (77.8%) had stable disease. CONCLUSION: The regimen of TAS-102, irinotecan, and bevacizumab is tolerable with antitumor activity for metastatic colorectal cancer patients refractory to first-line fluoropyrimidines and oxaliplatin treatment.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica , Bevacizumab , Neoplasias Colorrectales , Combinación de Medicamentos , Irinotecán , Pirrolidinas , Timina , Trifluridina , Uracilo , Humanos , Timina/administración & dosificación , Trifluridina/administración & dosificación , Trifluridina/uso terapéutico , Trifluridina/efectos adversos , Bevacizumab/administración & dosificación , Bevacizumab/efectos adversos , Bevacizumab/uso terapéutico , Masculino , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Femenino , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Persona de Mediana Edad , Pirrolidinas/administración & dosificación , Pirrolidinas/efectos adversos , Pirrolidinas/uso terapéutico , Anciano , Irinotecán/administración & dosificación , Irinotecán/efectos adversos , Irinotecán/uso terapéutico , Uracilo/análogos & derivados , Uracilo/administración & dosificación , Uracilo/uso terapéutico , Uracilo/efectos adversos , Adulto , Metástasis de la Neoplasia
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