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1.
Nature ; 624(7992): 621-629, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38049589

RESUMEN

Type 2 diabetes mellitus (T2D), a major cause of worldwide morbidity and mortality, is characterized by dysfunction of insulin-producing pancreatic islet ß cells1,2. T2D genome-wide association studies (GWAS) have identified hundreds of signals in non-coding and ß cell regulatory genomic regions, but deciphering their biological mechanisms remains challenging3-5. Here, to identify early disease-driving events, we performed traditional and multiplexed pancreatic tissue imaging, sorted-islet cell transcriptomics and islet functional analysis of early-stage T2D and control donors. By integrating diverse modalities, we show that early-stage T2D is characterized by ß cell-intrinsic defects that can be proportioned into gene regulatory modules with enrichment in signals of genetic risk. After identifying the ß cell hub gene and transcription factor RFX6 within one such module, we demonstrated multiple layers of genetic risk that converge on an RFX6-mediated network to reduce insulin secretion by ß cells. RFX6 perturbation in primary human islet cells alters ß cell chromatin architecture at regions enriched for T2D GWAS signals, and population-scale genetic analyses causally link genetically predicted reduced RFX6 expression with increased T2D risk. Understanding the molecular mechanisms of complex, systemic diseases necessitates integration of signals from multiple molecules, cells, organs and individuals, and thus we anticipate that this approach will be a useful template to identify and validate key regulatory networks and master hub genes for other diseases or traits using GWAS data.


Asunto(s)
Diabetes Mellitus Tipo 2 , Perfilación de la Expresión Génica , Redes Reguladoras de Genes , Predisposición Genética a la Enfermedad , Islotes Pancreáticos , Humanos , Estudios de Casos y Controles , Separación Celular , Cromatina/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Diabetes Mellitus Tipo 2/fisiopatología , Redes Reguladoras de Genes/genética , Estudio de Asociación del Genoma Completo , Secreción de Insulina , Islotes Pancreáticos/metabolismo , Islotes Pancreáticos/patología , Reproducibilidad de los Resultados
2.
Nature ; 611(7937): 818-826, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36385524

RESUMEN

Immune-related adverse events, particularly severe toxicities such as myocarditis, are major challenges to the utility of immune checkpoint inhibitors (ICIs) in anticancer therapy1. The pathogenesis of ICI-associated myocarditis (ICI-MC) is poorly understood. Pdcd1-/-Ctla4+/- mice recapitulate clinicopathological features of ICI-MC, including myocardial T cell infiltration2. Here, using single-cell RNA and T cell receptor (TCR) sequencing of cardiac immune infiltrates from Pdcd1-/-Ctla4+/- mice, we identify clonal effector CD8+ T cells as the dominant cell population. Treatment with anti-CD8-depleting, but not anti-CD4-depleting, antibodies improved the survival of Pdcd1-/-Ctla4+/- mice. Adoptive transfer of immune cells from mice with myocarditis induced fatal myocarditis in recipients, which required CD8+ T cells. The cardiac-specific protein α-myosin, which is absent from the thymus3,4, was identified as the cognate antigen source for three major histocompatibility complex class I-restricted TCRs derived from mice with fulminant myocarditis. Peripheral blood T cells from three patients with ICI-MC were expanded by α-myosin peptides. Moreover, these α-myosin-expanded T cells shared TCR clonotypes with diseased heart and skeletal muscle, which indicates that α-myosin may be a clinically important autoantigen in ICI-MC. These studies underscore the crucial role for cytotoxic CD8+ T cells, identify a candidate autoantigen in ICI-MC and yield new insights into the pathogenesis of ICI toxicity.


Asunto(s)
Linfocitos T CD8-positivos , Inmunoterapia , Miocarditis , Miosinas Ventriculares , Animales , Ratones , Autoantígenos/inmunología , Linfocitos T CD8-positivos/inmunología , Antígeno CTLA-4/deficiencia , Antígeno CTLA-4/genética , Inmunoterapia/efectos adversos , Miocarditis/inducido químicamente , Miocarditis/etiología , Miocarditis/mortalidad , Miocarditis/patología , Miosinas Ventriculares/inmunología
3.
Mol Genet Metab ; 142(1): 108360, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38428378

RESUMEN

The Mendelian disorders of chromatin machinery (MDCMs) represent a distinct subgroup of disorders that present with neurodevelopmental disability. The chromatin machinery regulates gene expression by a range of mechanisms, including by post-translational modification of histones, responding to histone marks, and remodelling nucleosomes. Some of the MDCMs that impact on histone modification may have potential therapeutic interventions. Two potential treatment strategies are to enhance the intracellular pool of metabolites that can act as substrates for histone modifiers and the use of medications that may inhibit or promote the modification of histone residues to influence gene expression. In this article we discuss the influence and potential treatments of histone modifications involving histone acetylation and histone methylation. Genomic technologies are facilitating earlier diagnosis of many Mendelian disorders, providing potential opportunities for early treatment from infancy. This has parallels with how inborn errors of metabolism have been afforded early treatment with newborn screening. Before this promise can be fulfilled, we require greater understanding of the biochemical fingerprint of these conditions, which may provide opportunities to supplement metabolites that can act as substrates for chromatin modifying enzymes. Importantly, understanding the metabolomic profile of affected individuals may also provide disorder-specific biomarkers that will be critical for demonstrating efficacy of treatment, as treatment response may not be able to be accurately assessed by clinical measures.


Asunto(s)
Cromatina , Redes y Vías Metabólicas , Humanos , Cromatina/genética , Cromatina/metabolismo , Redes y Vías Metabólicas/genética , Histonas/metabolismo , Histonas/genética , Procesamiento Proteico-Postraduccional , Acetilación , Errores Innatos del Metabolismo/genética , Errores Innatos del Metabolismo/terapia , Errores Innatos del Metabolismo/diagnóstico , Errores Innatos del Metabolismo/metabolismo , Ensamble y Desensamble de Cromatina/genética , Enfermedades Genéticas Congénitas/genética , Enfermedades Genéticas Congénitas/terapia , Enfermedades Genéticas Congénitas/metabolismo , Recién Nacido , Metilación
4.
Oncologist ; 27(12): e967-e969, 2022 12 09.
Artículo en Inglés | MEDLINE | ID: mdl-36288471

RESUMEN

Immune checkpoint inhibitor (ICI)-induced hypophysitis is an immune-mediated pituitary inflammation that tends to cause long-term pituitary deficiency. Management of ICI-induced hypophysitis includes corticosteroids for acute inflammation and long-term hormone replacement due to irreversible pituitary cell damage. We report a case of recurrent hypophysitis following ICI rechallenge for metastatic melanoma. A 33-year-old woman with recurrent metastatic melanoma with adrenal, pelvic, and inguinal metastases developed recurrent hypophysitis during treatment with ipilimumab and nivolumab which recurred with rechallenge >5 years later. In both cases, headache was the most notable symptom and brain MRI showed pituitary enlargement and edema without evidence of metastases. Central adrenal insufficiency and symptoms caused by mass effect were treated with acute high-dose corticosteroids and long-term replacement corticosteroids. Based on recurrence and failure of symptomatic treatment with continued steroid treatment, ICI was discontinued. This case illustrates that hypophysitis may recur with ICI rechallenge, challenging traditional assumptions that chronic, irreversible irAEs are unlikely to recur or flare. The regenerative potential of pituitary cells after ICI-induced damage or additional damage to previously unaffected cells may be more conceivable than previously realized. Additional research on the potential for recurrent ICI-induced endocrinopathies are needed.


Asunto(s)
Inhibidores de Puntos de Control Inmunológico , Melanoma , Humanos , Adulto , Melanoma/tratamiento farmacológico
5.
Diabetologia ; 63(7): 1418-1423, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32388592

RESUMEN

AIMS/HYPOTHESIS: Individuals with longstanding and recent-onset type 1 diabetes have a smaller pancreas. Since beta cells represent a very small portion of the pancreas, the loss of pancreas volume in diabetes is primarily due to the loss of pancreatic exocrine mass. However, the structural changes in the exocrine pancreas in diabetes are not well understood. METHODS: To characterise the pancreatic endocrine and exocrine compartments in diabetes, we studied pancreases from adult donors with type 1 diabetes compared with similarly aged donors without diabetes. Islet cell mass, islet morphometry, exocrine mass, acinar cell size and number and pancreas fibrosis were assessed by immunohistochemical staining. To better understand possible mechanisms of altered pancreas size, we measured pancreas size in three mouse models of insulin deficiency. RESULTS: Pancreases from donors with type 1 diabetes were approximately 45% smaller than those from donors without diabetes (47.4 ± 2.6 vs 85.7 ± 3.7 g), independent of diabetes duration or age of onset. Diabetic donor pancreases had decreased beta cell mass (0.061 ± 0.025 vs 0.94 ± 0.21 g) and reduced total exocrine mass (42.0 ± 4.9 vs 96.1 ± 6.5 g). Diabetic acinar cells were similar in size but fewer in number compared with those in pancreases from non-diabetic donors (63.7 ± 8.1 × 109 vs 121.6 ± 12.2 × 109 cells/pancreas), likely accounting for the difference in pancreas size. Within the type 1 diabetes exocrine tissue, there was a greater degree of fibrosis. The pancreases in three mouse models of insulin deficiency were similar in size to those in control mice. CONCLUSIONS/INTERPRETATION: Pancreases from donors with type 1 diabetes are smaller than normal donor pancreases because exocrine cells are fewer in number rather than smaller in size; these changes occur early in the disease process. Our mouse data suggest that decreased pancreas size in type 1 diabetes is not directly caused by insulin deficiency, but the precise mechanism responsible remains unclear.


Asunto(s)
Diabetes Mellitus Tipo 1/metabolismo , Páncreas Exocrino/metabolismo , Células Acinares/metabolismo , Animales , Femenino , Células Secretoras de Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Ratones , Páncreas/metabolismo
6.
Hippocampus ; 28(5): 327-337, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29431270

RESUMEN

Key pathological features of Parkinson's Disease (PD) include the progressive degeneration of midbrain dopaminergic (DA) neurons and hindbrain noradrenergic (NA) neurons. The loss of DA neurons has been extensively studied and is the main cause of motor dysfunction. Importantly, however, there are a range of 'non-movement' related features of PD including cognitive dysfunction, sleep disturbances and mood disorders. The origins for these non-motor symptoms are less clear, but a possible substrate for cognitive decline may be reduced adult-hippocampal neurogenesis, which is reported to be impaired in PD. The mechanisms underlying reduced neurogenesis in PD are not well established. Here we tested the hypothesis that NA and DA depletion, as occurs in PD, impairs hippocampal neurogenesis. We used 6-hydroxydopamine or the immunotoxin dopamine-ß-hydroxylase-saporin to selectively lesion DA or NA neurons, respectively, in adult Sprague Dawley rats and assessed hippocampal neurogenesis through phenotyping of cells birth-dated using 5-bromo-2'-deoxyuridine. The results showed no difference in proliferation or differentiation of newborn cells in the subgranular zone of the dentate gyrus after NA or DA lesions. This suggests that impairment of hippocampal neurogenesis in PD likely results from mechanisms independent of, or in addition to degeneration of DA and NA neurons.


Asunto(s)
Neuronas Adrenérgicas/patología , Encéfalo/patología , Neuronas Dopaminérgicas/patología , Neurogénesis , Trastornos Parkinsonianos/patología , Neuronas Adrenérgicas/metabolismo , Animales , Encéfalo/metabolismo , Bromodesoxiuridina , Muerte Celular , Dopamina/metabolismo , Dopamina beta-Hidroxilasa , Neuronas Dopaminérgicas/metabolismo , Femenino , Antígeno Ki-67/metabolismo , Degeneración Nerviosa/metabolismo , Degeneración Nerviosa/patología , Células-Madre Neurales/metabolismo , Células-Madre Neurales/patología , Neurogénesis/fisiología , Norepinefrina/metabolismo , Oxidopamina , Trastornos Parkinsonianos/metabolismo , Ratas Sprague-Dawley , Saporinas
7.
J Community Health ; 42(2): 344-348, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27638034

RESUMEN

Our objectives was to create an initiative to change the culture of a small community to improve quality of life as it relates to health for the residents through the use of health-related educational sessions, a coordinated fitness and nutrition program, and the construction of community fitness trails. We compared the use of a health-focused community driven program to the status quo in seeking opportunities to improve perception and understanding of one's health and overall quality of life for participants. Among the various techniques identified to improve a community's health outcomes, dissemination of information through the use of educational sessions empowered citizens to take control of their health status, and ultimately, their quality of life. This came with zero negative impacts for those providing the education, as well as those participating in the sessions. Although the application of these methods depends on local resources, leadership, and partnerships, programs similar to those presented here can help to improve quality of life for citizens in communities across the country facing the challenges secondary to a sedentary lifestyle.


Asunto(s)
Servicios de Salud Comunitaria/organización & administración , Diabetes Mellitus Tipo 2/prevención & control , Obesidad/prevención & control , Educación del Paciente como Asunto/organización & administración , Adulto , Servicios de Salud Comunitaria/métodos , Estado de Salud , Humanos , Educación del Paciente como Asunto/métodos , Educación y Entrenamiento Físico/métodos , Educación y Entrenamiento Físico/organización & administración , Calidad de Vida , Tennessee , Programas de Reducción de Peso/métodos , Programas de Reducción de Peso/organización & administración
8.
J Biol Chem ; 290(25): 15450-15461, 2015 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-25934393

RESUMEN

ATP-sensitive potassium (KATP) channels are heteromultimeric complexes of an inwardly rectifying Kir channel (Kir6.x) and sulfonylurea receptors. Their regulation by intracellular ATP and ADP generates electrical signals in response to changes in cellular metabolism. We investigated channel elements that control the kinetics of ATP-dependent regulation of KATP (Kir6.2 + SUR1) channels using rapid concentration jumps. WT Kir6.2 channels re-open after rapid washout of ATP with a time constant of ∼60 ms. Extending similar kinetic measurements to numerous mutants revealed fairly modest effects on gating kinetics despite significant changes in ATP sensitivity and open probability. However, we identified a pair of highly conserved neighboring amino acids (Trp-68 and Lys-170) that control the rate of channel opening and inhibition in response to ATP. Paradoxically, mutations of Trp-68 or Lys-170 markedly slow the kinetics of channel opening (500 and 700 ms for W68L and K170N, respectively), while increasing channel open probability. Examining the functional effects of these residues using φ value analysis revealed a steep negative slope. This finding implies that these residues play a role in lowering the transition state energy barrier between open and closed channel states. Using unnatural amino acid incorporation, we demonstrate the requirement for a planar amino acid at Kir6.2 position 68 for normal channel gating, which is potentially necessary to localize the ϵ-amine of Lys-170 in the phosphatidylinositol 4,5-bisphosphate-binding site. Overall, our findings identify a discrete pair of highly conserved residues with an essential role for controlling gating kinetics of Kir channels.


Asunto(s)
Canales de Potasio de Rectificación Interna/química , Sustitución de Aminoácidos , Animales , Sitios de Unión , Cinética , Ratones , Mutación Missense , Canales de Potasio de Rectificación Interna/genética , Canales de Potasio de Rectificación Interna/metabolismo , Receptores de Sulfonilureas/química , Receptores de Sulfonilureas/genética , Receptores de Sulfonilureas/metabolismo
9.
J Gen Virol ; 97(8): 1955-1967, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27217299

RESUMEN

Promyelocytic leukemia (PML) proteins have been implicated in antiviral responses but PML and associated proteins are also suggested to support virus replication. One isoform, PML-II, is required for efficient transcription of interferon and interferon-responsive genes. We therefore investigated the PML-II contribution to human adenovirus 5 (Ad5) infection, using shRNA-mediated knockdown. HelaΔII cells showed a 2-3-fold elevation in Ad5 yield, reflecting an increase in late gene expression. This increase was found to be due in part to the reduced innate immune response consequent upon PML-II depletion. However, the effect was minor because the viral E4 Orf3 protein targets and inactivates this PML-II function. The major benefit to Ad5 in HelaΔII cells was exerted via an increase in HSP70; depletion of HSP70 completely reversed this replicative advantage. Increased Ad5 late gene expression was not due either to the previously described inhibition of inflammatory responses by HSP70 or to effects of HSP70 on major late promoter or L4 promoter activity, but might be linked to an observed increase in E1B 55K, as this protein is known to be required for efficient late gene expression. The induction of HSP70 by PML-II removal was specific for the HSPA1B gene among the HSP70 gene family and thus was not the consequence of a general stress response. Taken together, these data show that PML-II, through its various actions, has an overall negative effect on the Ad5 lifecycle.


Asunto(s)
Adenovirus Humanos/inmunología , Proteínas HSP70 de Choque Térmico/metabolismo , Interferones/metabolismo , Proteína de la Leucemia Promielocítica/metabolismo , Isoformas de Proteínas/metabolismo , Técnicas de Silenciamiento del Gen , Células HeLa , Humanos , Inmunidad Innata , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo
10.
J Virol ; 89(14): 7053-63, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25926634

RESUMEN

UNLABELLED: The late phase of adenovirus gene expression is controlled by proteins made in the intermediate phase, including L4 proteins of 22,000- and 33,000-Da apparent molecular mass (L4-22K and -33K proteins) that are expressed initially from the L4 promoter (L4P). The L4P is activated by a combination of viral proteins and cellular p53 and is ultimately inhibited again by its own products. Here, we have examined the L4P of human adenovirus type 5 in detail and have defined its transcription start site, which our data suggest is positioned by a weak TATA box. Rather than contributing positively to promoter activity, a putative initiator element at the transcription start site acts as a target for negative regulation imposed on the L4P by cellular TFII-I. We show that this TFII-I inhibition is relieved by one of the previously defined viral activators of the L4P, the E4 Orf3 protein, which alters the pool of TFII-I in the cell. We also explore further the negative regulation of the L4P by its products and show that the L4-33K protein is more significant in this process than L4-22K. It is the combined actions of positive and negative factors that lead to the transient activation of the L4P at the onset of the late phase of adenovirus gene expression. IMPORTANCE: The adenovirus replication cycle proceeds through multiple phases of gene expression in which a key step is the activation of late-phase gene expression to produce proteins from which progeny particles can be formed. Working with human adenovirus type 5, we showed previously that two proteins expressed from the L4 region of the viral genome perform essential roles in moving the infection on into the late phase; these two proteins are produced by the action of a dedicated promoter, the L4P, and without them the infection does not proceed successfully to progeny generation. In this new work, we delineate further aspects of L4P activity and regulation. Understanding how the L4P works, and how it contributes to activation of the late phase of infection, is important to our understanding of natural infections by the virus, in which late gene expression can fail to occur, allowing the virus to persist.


Asunto(s)
Adenovirus Humanos/genética , Regulación Viral de la Expresión Génica , Interacciones Huésped-Patógeno , Regiones Promotoras Genéticas , Factores de Transcripción TFII/metabolismo , Proteínas Virales/biosíntesis , Línea Celular , Humanos , Sitio de Iniciación de la Transcripción
11.
BMC Med Inform Decis Mak ; 15: 28, 2015 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-25881112

RESUMEN

BACKGROUND: Manual eligibility screening (ES) for a clinical trial typically requires a labor-intensive review of patient records that utilizes many resources. Leveraging state-of-the-art natural language processing (NLP) and information extraction (IE) technologies, we sought to improve the efficiency of physician decision-making in clinical trial enrollment. In order to markedly reduce the pool of potential candidates for staff screening, we developed an automated ES algorithm to identify patients who meet core eligibility characteristics of an oncology clinical trial. METHODS: We collected narrative eligibility criteria from ClinicalTrials.gov for 55 clinical trials actively enrolling oncology patients in our institution between 12/01/2009 and 10/31/2011. In parallel, our ES algorithm extracted clinical and demographic information from the Electronic Health Record (EHR) data fields to represent profiles of all 215 oncology patients admitted to cancer treatment during the same period. The automated ES algorithm then matched the trial criteria with the patient profiles to identify potential trial-patient matches. Matching performance was validated on a reference set of 169 historical trial-patient enrollment decisions, and workload, precision, recall, negative predictive value (NPV) and specificity were calculated. RESULTS: Without automation, an oncologist would need to review 163 patients per trial on average to replicate the historical patient enrollment for each trial. This workload is reduced by 85% to 24 patients when using automated ES (precision/recall/NPV/specificity: 12.6%/100.0%/100.0%/89.9%). Without automation, an oncologist would need to review 42 trials per patient on average to replicate the patient-trial matches that occur in the retrospective data set. With automated ES this workload is reduced by 90% to four trials (precision/recall/NPV/specificity: 35.7%/100.0%/100.0%/95.5%). CONCLUSION: By leveraging NLP and IE technologies, automated ES could dramatically increase the trial screening efficiency of oncologists and enable participation of small practices, which are often left out from trial enrollment. The algorithm has the potential to significantly reduce the effort to execute clinical research at a point in time when new initiatives of the cancer care community intend to greatly expand both the access to trials and the number of available trials.


Asunto(s)
Ensayos Clínicos como Asunto/métodos , Determinación de la Elegibilidad/métodos , Almacenamiento y Recuperación de la Información/métodos , Procesamiento de Lenguaje Natural , Neoplasias/terapia , Selección de Paciente , Niño , Humanos
12.
J Biol Chem ; 288(3): 1896-906, 2013 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-23223446

RESUMEN

Classically, exit from the endoplasmic reticulum (ER) is rate-limiting for secretory protein trafficking because protein folding/assembly occurs there. In this study, we have exploited "hPro-CpepSfGFP," a human proinsulin bearing "superfolder" green fluorescent C-peptide expressed in pancreatic ß cells where it is processed to human insulin and CpepSfGFP. Remarkably, steady-state accumulation of hPro-CpepSfGFP and endogenous proinsulin is in the Golgi region, as if final stages of protein folding/assembly were occurring there. The Golgi regional distribution of proinsulin is dynamic, influenced by fasting/refeeding, and increased with ß cell zinc deficiency. However, coexpression of ER-entrapped mutant proinsulin-C(A7)Y shifts the steady-state distribution of wild-type proinsulin to the ER. Endogenous proinsulin coprecipitates with hPro-CpepSfGFP and even more so with hProC(A7)Y-CpepSfGFP. Using Cerulean and Venus-tagged proinsulins, we find that both WT-WT and WT-mutant proinsulin pairs exhibit FRET. The data demonstrate that wild-type proinsulin dimerizes within the ER but accumulates at a poorly recognized slow step within the Golgi region, reflecting either slow kinetics of proinsulin hexamerization, steps in formation of nascent secretory granules, or other unknown molecular events. However, in the presence of ongoing misfolding of a subpopulation of proinsulin in ß cells, the rate-limiting step in transport of the remaining proinsulin shifts to the ER.


Asunto(s)
Péptido C/metabolismo , Retículo Endoplásmico/metabolismo , Aparato de Golgi/metabolismo , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Animales , Péptido C/química , Péptido C/genética , Células COS , Línea Celular Tumoral , Chlorocebus aethiops , Dimerización , Retículo Endoplásmico/genética , Retículo Endoplásmico/ultraestructura , Expresión Génica , Aparato de Golgi/genética , Aparato de Golgi/ultraestructura , Proteínas Fluorescentes Verdes/química , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Insulina/química , Insulina/genética , Células Secretoras de Insulina/citología , Cinética , Ratones , Microscopía Confocal , Plásmidos , Unión Proteica , Pliegue de Proteína , Transporte de Proteínas , Ratas , Transfección
13.
J Biol Chem ; 288(43): 31010-8, 2013 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-24022479

RESUMEN

Upon chronic up-regulation of proinsulin synthesis, misfolded proinsulin can accumulate in the endoplasmic reticulum (ER) of pancreatic ß-cells, promoting ER stress and type 2 diabetes mellitus. In Mutant Ins-gene-induced Diabetes of Youth (MIDY), misfolded mutant proinsulin impairs ER exit of co-expressed wild-type proinsulin, limiting insulin production and leading to eventual ß-cell death. In this study we have investigated the hypothesis that increased expression of ER oxidoreductin-1α (Ero1α), despite its established role in the generation of H2O2, might nevertheless be beneficial in limiting proinsulin misfolding and its adverse downstream consequences. Increased Ero1α expression is effective in promoting wild-type proinsulin export from cells co-expressing misfolded mutant proinsulin. In addition, we find that upon increased Ero1α expression, some of the MIDY mutants themselves are directly rescued from ER retention. Secretory rescue of proinsulin-G(B23)V is correlated with improved oxidative folding of mutant proinsulin. Indeed, using three different variants of Ero1α, we find that expression of either wild-type or an Ero1α variant lacking regulatory disulfides can rescue mutant proinsulin-G(B23)V, in parallel with its ability to provide an oxidizing environment in the ER lumen, whereas beneficial effects were less apparent for a redox-inactive form of Ero1. Increased expression of protein disulfide isomerase antagonizes the rescue provided by oxidatively active Ero1. Importantly, ER stress induced by misfolded proinsulin was limited by increased expression of Ero1α, suggesting that enhancing the oxidative folding of proinsulin may be a viable therapeutic strategy in the treatment of type 2 diabetes.


Asunto(s)
Estrés del Retículo Endoplásmico , Células Secretoras de Insulina/metabolismo , Glicoproteínas de Membrana/biosíntesis , Mutación Missense , Oxidorreductasas/biosíntesis , Proinsulina/metabolismo , Pliegue de Proteína , Sustitución de Aminoácidos , Animales , Línea Celular , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/terapia , Regulación de la Expresión Génica , Humanos , Peróxido de Hidrógeno/metabolismo , Células Secretoras de Insulina/patología , Glicoproteínas de Membrana/genética , Ratones , Oxidación-Reducción , Oxidorreductasas/genética , Proinsulina/genética
14.
Hum Mol Genet ; 21(11): 2559-71, 2012 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-22388933

RESUMEN

Duchenne muscular dystrophy (DMD) is a severe neuromuscular disorder caused by mutations in the dystrophin gene that result in the absence of functional protein. Antisense-mediated exon skipping is one of the most promising approaches for the treatment of DMD and recent clinical trials have demonstrated encouraging results. However, antisense oligonucleotide-mediated exon skipping for DMD still faces major hurdles such as extremely low efficacy in the cardiac muscle, poor cellular uptake and relatively rapid clearance from circulation, which means that repeated administrations are required to achieve some therapeutic efficacy. To overcome these limitations, we previously proposed the use of small nuclear RNAs (snRNAs), especially U7snRNA to shuttle the antisense sequences after vectorization into adeno-associated virus (AAV) vectors. In this study, we report for the first time the efficiency of the AAV-mediated exon skipping approach in the utrophin/dystrophin double-knockout (dKO) mouse which is a very severe and progressive mouse model of DMD. Following a single intravenous injection of scAAV9-U7ex23 in dKO mice, near-normal levels of dystrophin expression were restored in all muscles examined, including the heart. This resulted in a considerable improvement of their muscle function and dystrophic pathology as well as a remarkable extension of the dKO mice lifespan. These findings suggest great potential for AAV-U7 in systemic treatment of the DMD phenotype.


Asunto(s)
Dependovirus/genética , Distrofina/genética , Exones , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/terapia , ARN Nuclear Pequeño/genética , Utrofina/genética , Animales , Dependovirus/metabolismo , Modelos Animales de Enfermedad , Distrofina/metabolismo , Terapia Genética , Ratones , Distrofia Muscular de Duchenne/patología , Fenotipo , ARN Nuclear Pequeño/uso terapéutico , Utrofina/metabolismo
15.
J Virol ; 87(21): 11617-25, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23966406

RESUMEN

During adenovirus infection, the emphasis of gene expression switches from early genes to late genes in a highly regulated manner. Two gene products, L4-22K and L4-33K, contribute to this switch by activating the major late transcription unit (MLTU) and regulating the splicing of its transcript. L4-22K and L4-33K expression is driven initially by a recently described L4 promoter (L4P) embedded within the MLTU that is activated by early and intermediate viral factors: E1A, E4 Orf3, and IVa2. Here we show that this promoter is also significantly activated by the cellular stress response regulator, p53. Exogenous expression of p53 activated L4P in reporter assays, while depletion of endogenous p53 inhibited the induction of L4P by viral activators. Chromatin immunoprecipitation studies showed that p53 associates with L4P and that during adenovirus type 5 (Ad5) infection, this association peaks at 12 h postinfection, coinciding with the phase of the infectious cycle when L4P is active, and is then lost as MLP activation commences. p53 activation of L4P is significant during Ad5 infection, since depletion of p53 prior to infection of either immortalized or normal cells led to severely reduced late gene expression. The association of p53 with L4P is transient due to the action of products of L4P activity (L4-22K/33K), which establish a negative feedback loop that ensures the transient activity of L4P at the start of the late phase and contributes to an efficient switch from early- to late-phase virus gene expression.


Asunto(s)
Adenovirus Humanos/genética , Regulación Viral de la Expresión Génica , Interacciones Huésped-Patógeno , Regiones Promotoras Genéticas , Activación Transcripcional , Proteína p53 Supresora de Tumor/metabolismo , Línea Celular , Inmunoprecipitación de Cromatina , Humanos , Unión Proteica
16.
Diabetes Care ; 47(3): 393-400, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38151474

RESUMEN

OBJECTIVE: This multicenter prospective cohort study compared pancreas volume as assessed by MRI, metabolic scores derived from oral glucose tolerance testing (OGTT), and a combination of pancreas volume and metabolic scores for predicting progression to stage 3 type 1 diabetes (T1D) in individuals with multiple diabetes-related autoantibodies. RESEARCH DESIGN AND METHODS: Pancreas MRI was performed in 65 multiple autoantibody-positive participants enrolled in the Type 1 Diabetes TrialNet Pathway to Prevention study. Prediction of progression to stage 3 T1D was assessed using pancreas volume index (PVI), OGTT-derived Index60 score and Diabetes Prevention Trial-Type 1 Risk Score (DPTRS), and a combination of PVI and DPTRS. RESULTS: PVI, Index60, and DPTRS were all significantly different at study entry in 11 individuals who subsequently experienced progression to stage 3 T1D compared with 54 participants who did not experience progression (P < 0.005). PVI did not correlate with metabolic testing across individual study participants. PVI declined longitudinally in the 11 individuals diagnosed with stage 3 T1D, whereas Index60 and DPTRS increased. The area under the receiver operating characteristic curve for predicting progression to stage 3 from measurements at study entry was 0.76 for PVI, 0.79 for Index60, 0.79 for DPTRS, and 0.91 for PVI plus DPTRS. CONCLUSIONS: These findings suggest that measures of pancreas volume and metabolism reflect distinct components of risk for developing stage 3 type 1 diabetes and that a combination of these measures may provide superior prediction than either alone.


Asunto(s)
Diabetes Mellitus Tipo 1 , Humanos , Diabetes Mellitus Tipo 1/diagnóstico , Estudios Prospectivos , Páncreas/diagnóstico por imagen , Páncreas/metabolismo , Factores de Riesgo , Autoanticuerpos , Imagen por Resonancia Magnética
17.
J Physiol ; 591(1): 67-76, 2013 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-23129797

RESUMEN

Substantial advances have been made in the last decade on our understanding of the basic physiology underlying neurogenesis in the postnatal mammalian brain. The bulk of the work in this area has been based on analysis of the adult brain. Relatively less is known about the capacity for neurogenesis in specific structures within the neonatal brain. Here we report that the production of medium spiny striatal projection neurons extends into the early neonatal period under normal physiological conditions in the rat brain. Birth-dating of newborn cells with bromodeoxyuridine at postnatal days 0, 2 and 5 showed a peak production close to birth, which sharply declined at the later time-points. Additionally, there was a low-level but stable contribution of neurons with interneuron identity over the same time-period. Importantly, retroviral labelling of new striatal projection neurons with green fluorescent protein showed long-term survival and terminal differentiation with characteristic morphology, including highly elaborated spiny dendrites, and appropriate axonal targeting of the globus pallidus and midbrain. This latent period of striatal neurogenesis in the early neonatal brain represents an interesting target for regenerative approaches aimed at restoring striatal circuitry in perinatal pathologies, such as hypoxic and ischaemic damage associated with cerebral palsy.


Asunto(s)
Animales Recién Nacidos/fisiología , Cuerpo Estriado/fisiología , Neuronas/fisiología , Animales , Femenino , Neurogénesis , Ratas , Ratas Sprague-Dawley
18.
Mol Ther ; 20(6): 1212-21, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22354379

RESUMEN

Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disorder caused by mutations in the dystrophin gene. Antisense-mediated exon skipping is one of the most promising approaches for the treatment of DMD but still faces personalized medicine challenges as different mutations found in DMD patients require skipping of different exons. However, 70% of DMD patients harbor dystrophin gene deletions in a mutation-rich area or "hot-spot" in the central genomic region. In this study, we have developed 11 different U7 small-nuclear RNA, to shuttle antisense sequences designed to mask key elements involved in the splicing of exons 45 to 55. We demonstrate that these constructs induce efficient exon skipping both in vitro in DMD patients' myoblasts and in vivo in human DMD (hDMD) mice and that they can be combined into a single vector to achieve a multi skipping of at least 3 exons. These very encouraging results provide proof of principle that efficient multiexon-skipping can be achieved using adeno-associated viral (AAV) vectors encoding multiple U7 small-nuclear RNAs (U7snRNAs), offering therefore very promising tools for clinical treatment of DMD.


Asunto(s)
Empalme Alternativo , Distrofina/genética , Exones , Vectores Genéticos , Distrofia Muscular de Duchenne/genética , ARN Nuclear Pequeño , Animales , Línea Celular , ADN sin Sentido , Dependovirus/genética , Modelos Animales de Enfermedad , Orden Génico , Humanos , Lentivirus/genética , Ratones , Ratones Transgénicos , Distrofia Muscular de Duchenne/terapia , Mioblastos/metabolismo , Transducción Genética
19.
J Clin Endocrinol Metab ; 108(6): 1514-1525, 2023 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-36481794

RESUMEN

Immune checkpoint inhibitors (ICI) are cancer therapies that are approved for use in at least 19 different cancers. They function by stimulating immune cell responses against cancer, and their toxicities comprise a host of autoinflammatory syndromes that may impact any organ system. Endocrine toxicities occur in as high as 25% to 50% of ICI recipients, depending on the treatment regimen used. These toxicities vary in severity from mild, asymptomatic cases of subclinical hypothyroidism to severe, fatal cases of adrenal crisis, thyroid dysfunction, or diabetic ketoacidosis. Thus, timely recognition and treatment is critical. Herein, we present clinical cases of ICI-induced thyroid dysfunction, hypophysitis, and insulin-dependent diabetes mellitus. We use these cases to discuss the screening, diagnosis, and management of ICI-associated endocrine dysfunction.


Asunto(s)
Diabetes Mellitus Tipo 1 , Neoplasias , Enfermedades de la Tiroides , Humanos , Inhibidores de Puntos de Control Inmunológico/efectos adversos , Inmunoterapia/efectos adversos , Neoplasias/tratamiento farmacológico , Diabetes Mellitus Tipo 1/inducido químicamente , Diabetes Mellitus Tipo 1/tratamiento farmacológico
20.
Health Lit Res Pract ; 7(4): e215-e224, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38061760

RESUMEN

BACKGROUND: Previous studies showed that deaf and hard-of-hearing (DHH) individuals have low health literacy related to prescription labels. This study examined the DHH's experience with understanding prescription labels and how technology can impact that experience. OBJECTIVES: The purpose of this qualitative study was twofold: (1) gain a more enhanced understanding of DHH experiences in understanding prescription labels with a focus on language needs, expectations, and preferences, and (2) assess the potential role of technology in addressing the communication-related accessibility issues which emerge from the data. METHODS: In this study, 25 Deaf American Sign Language users who picked up a prescription from a pharmacy within the past year were interviewed. A thematic analysis, which included a systematic coding process, was used to uncover themes about their experiences picking up and using prescription medications. KEY RESULTS: Thematic analyses identified that medication-related experiences centered around themes: (1) medication information seeking; (2) comfort taking medication; (3) picking up medication; and (4) communication with the pharmacy team. A large contributor to the communication experience was the perception that the pharmacist was not being respectful. Regarding comfort taking medications, 12% of participants expressed a lack of understanding medications while taking medication. This led to participants largely using online resources when seeking medication information. This study also found that technology greatly aided the participants during this experience. CONCLUSION: This study recorded the experiences within the context of limited health literacy and aversive audism found that the DHH individual repeatedly encountered communication barriers, which may contribute to their poor medication literacy. Thus, future studies should explore how to leverage the potential benefits of technology to improve the pharmacy experience of the DHH, thereby improving medication literacy. [HLRP: Health Literacy Research and Practice. 2023;7(4):e215-e224.].


PLAIN LANGUAGE SUMMARY: Previous studies have shown that deaf and hard-of-hearing (DHH) individuals have low health literacy and higher rates of unintentional medication misuse. DHH participants described their experiences related to the pharmacy and technology, as situated around negative attitudes and language barriers. Based on four themes, which emerged from our analysis, we identified areas where may help to reduce these care inequities.


Asunto(s)
Pérdida Auditiva , Personas con Deficiencia Auditiva , Humanos , Estados Unidos , Lengua de Signos , Lenguaje , Comunicación
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