RESUMEN

MAF1, a key repressor of RNA polymerase (pol) III-mediated transcription, has been shown to promote mesoderm formation in vitro. Here, we show that MAF1 plays a critical role in regulating osteoblast differentiation and bone mass. Global deletion of MAF1 (Maf1-/- mice) produced a high bone mass phenotype. However, osteoblasts isolated from Maf1-/- mice showed reduced osteoblastogenesis ex vivo. Therefore, we determined the phenotype of mice overexpressing MAF1 in cells from the mesenchymal lineage (Prx1-Cre;LSL-MAF1 mice). These mice showed increased bone mass. Ex vivo, cells from these mice showed enhanced osteoblastogenesis concordant with their high bone mass phenotype. Thus, the high bone mass phenotype in Maf1-/- mice is likely due to confounding effects from the global absence of MAF1. MAF1 overexpression promoted osteoblast differentiation of ST2 cells while MAF1 downregulation inhibited differentiation, indicating MAF1 enhances osteoblast formation. However, other perturbations used to repress RNA pol III transcription, inhibited osteoblast differentiation. However, decreasing RNA pol III transcription through these perturbations enhanced adipogenesis in ST2 cells. RNA-seq analyzed the basis for these opposing actions on osteoblast differentiation. The different modalities used to perturb RNA pol III transcription resulted in distinct gene expression changes, indicating that this transcription process is highly sensitive and triggers diverse gene expression programs and phenotypic outcomes. Specifically, MAF1 induced genes known to promote osteoblast differentiation. Furthermore, genes that are induced during osteoblast differentiation displayed codon bias. Together, these results reveal a novel role for MAF1 and RNA pol III-mediated transcription in osteoblast fate determination, differentiation, and bone mass regulation.

Asunto(s)

ARN Polimerasa III , Proteínas Represoras , Animales , Proteína 1 Similar al Receptor de Interleucina-1 , Ratones , Prolapso de la Válvula Mitral , Miopía , ARN , ARN Polimerasa III/genética , ARN Polimerasa III/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Enfermedades de la Piel , Transcripción Genética

RESUMEN

Purpose: Interprofessional collaboration in health care is needed for comprehensive patient care and improved health outcomes. The purpose of this study was to assess dental hygienists' attitudes and behaviors on past interprofessional education experiences to determine how those experiences influence the ways they collaborate with other health care professionals.Methods: Licensed dental hygienists in the United States were recruited to participate in this mixed methods study via social media sites and through the constituents of the American Dental Hygienists' Association. The survey instrument consisted of 23 items incorporating quantitative Likert-style, multiple-choice and qualitative open-ended questions designed to measure participants' attitudes towards interprofessional collaboration (IPC) and interprofessional education (IPE), IPC behaviors in practice and previous IPE experiences.Results: Of the 184 participants who opened the survey, 165 respondents met the inclusion criteria and completed the survey (n=165). Most of the participants indicated the belief that IPC was important (90%, n=147) and felt confident collaborating with other health care professionals (81%, n=133). While two-thirds of the respondents did not report previous IPE experience (66%, n=109), the majority reported collaborating with other health care professionals within the past six months (63%, n=102). Respondents who reported prior IPE, collaborated with other health care professionals more frequently, on average, than those without IPE experience. Most IPE experiences were case studies and on- and off-campus clinical rotations.Conclusion: Findings suggest dental hygienists appreciate the importance of IPC and collaborate with other health care providers based on those attitudes, regardless of prior IPE experiences. Further research examining the best practices of IPE experiences could enrich the value of future collaborations between dental hygienists and other health care providers.

Asunto(s)

Higienistas Dentales , Educación Interprofesional , Actitud , Actitud del Personal de Salud , Humanos , Relaciones Interprofesionales , Encuestas y Cuestionarios , Estados Unidos

RESUMEN

Given the disruption caused by the COVID-19 pandemic, life as we knew it has been turned upside down, but the need for science to go on has never been stronger. In the realm of scientific conferences, with the requirement for social distancing, the importance of wearing face coverings, and travel restrictions, only virtual meetings have been possible during the pandemic. But many are asking: What is the new post-pandemic normal likely to be? Do we still want to have in-person meetings when the restrictions are eased? Assuming we do, when will they be possible again, and under what conditions? Regardless of what the benefits of virtual symposia might be, are they here to stay? These questions, and many more that are being asked around the world today, are the subject of this perspective. Herein, we attempt to provide useful context and insight into where scientific meetings have been, where they are today, where they are going, and how they will get there. Our conclusion is that the pandemic has created an accelerated opportunity to make the world of future scientific conferences better in a "both/and" collaborative in-person/virtual scenario, not the more limited "pick one" choice.

RESUMEN

BACKGROUND AND AIMS: This study examined whether enhanced susceptibility of steatotic liver to ischemia-reperfusion (I/R) injury is due to impaired recruitment of bone marrow (BM) progenitors of liver sinusoidal endothelial cells (LSECs, also called sinusoidal endothelial cell progenitor cells [sprocs]) with diminished repair of injured LSECs and whether restoring signaling to recruit BM sprocs reduces I/R injury. APPROACH AND RESULTS: Hepatic vessels were clamped for 1 hour in rats fed a high-fat, high-fructose (HFHF) diet for 5, 10, or 15 weeks. Matrix metalloproteinase 9 (MMP-9) antisense oligonucleotides (ASO) or an MMP inhibitor were used to induce liver-selective MMP-9 inhibition. HFHF rats had mild, moderate, and severe steatosis, respectively, at 5, 10, and 15 weeks. I/R injury was enhanced in HFHF rats; this was accompanied by complete absence of hepatic vascular endothelial growth factor (VEGF)-stromal cell-derived factor 1 (sdf1) signaling, leading to lack of BM sproc recruitment. Liver-selective MMP-9 inhibition to protect against proteolytic cleavage of hepatic VEGF using either MMP-9 ASO or intraportal MMP inhibitor in 5-week and 10-week HFHF rats enhanced hepatic VEGF-sdf1 signaling, increased BM sproc recruitment, and reduced alanine aminotransferase (ALT) by 92% and 77% at 5 weeks and by 80% and 64% at 10 weeks of the HFHF diet, respectively. After I/R injury in 15-week HFHF rats, the MMP inhibitor reduced active MMP-9 expression by 97%, ameliorated histologic evidence of injury, and reduced ALT by 58%, which is comparable to control rats sustaining I/R injury. Rescue therapy with intraportal MMP inhibitor, given after ischemia, in the 5-week HFHF rat reduced ALT by 71% and reduced necrosis. CONCLUSIONS: Lack of signaling to recruit BM sprocs that repair injured LSECs renders steatotic liver more susceptible to I/R injury. Liver-selective MMP-9 inhibition enhances VEGF-sdf1 signaling and recruitment of BM sprocs, which markedly protects against I/R injury, even in severely steatotic rats.

Asunto(s)

Células Progenitoras Endoteliales/efectos de los fármacos , Hígado Graso/etiología , Metaloproteinasa 9 de la Matriz/metabolismo , Inhibidores de la Metaloproteinasa de la Matriz/farmacología , Daño por Reperfusión/prevención & control , Animales , Trasplante de Médula Ósea , Dieta Alta en Grasa , Azúcares de la Dieta/efectos adversos , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades/terapia , Células Progenitoras Endoteliales/patología , Hígado Graso/diagnóstico , Hígado Graso/tratamiento farmacológico , Fructosa/efectos adversos , Humanos , Hígado/irrigación sanguínea , Hígado/diagnóstico por imagen , Hígado/efectos de los fármacos , Hígado/patología , Masculino , Inhibidores de la Metaloproteinasa de la Matriz/uso terapéutico , Microvasos/citología , Microvasos/efectos de los fármacos , Microvasos/patología , Ratas , Daño por Reperfusión/etiología

RESUMEN

MAF1 homolog, negative regulator of RNA polymerase III (MAF1) is a key repressor of RNA polymerase (pol) III-dependent transcription and functions as a tumor suppressor. Its expression is frequently down-regulated in primary human hepatocellular carcinomas (HCCs). However, this reduction in MAF1 protein levels does not correlate with its transcript levels, indicating that MAF1 is regulated post-transcriptionally. Here, we demonstrate that MAF1 is a labile protein whose levels are regulated through the ubiquitin-dependent proteasome pathway. We found that MAF1 ubiquitination is enhanced upon mTOR complex 1 (TORC1)-mediated phosphorylation at Ser-75. Moreover, we observed that the E3 ubiquitin ligase cullin 2 (CUL2) critically regulates MAF1 ubiquitination and controls its stability and subsequent RNA pol III-dependent transcription. Analysis of the phenotypic consequences of modulating either CUL2 or MAF1 protein expression revealed changes in actin cytoskeleton reorganization and altered sensitivity to doxorubicin-induced apoptosis. Repression of RNA pol III-dependent transcription by chemical inhibition or knockdown of BRF1 RNA pol III transcription initiation factor subunit (BRF1) enhanced HCC cell sensitivity to doxorubicin, suggesting that MAF1 regulates doxorubicin resistance in HCC by controlling RNA pol III-dependent transcription. Together, our results identify the ubiquitin proteasome pathway and CUL2 as important regulators of MAF1 levels. They suggest that decreases in MAF1 protein underlie chemoresistance in HCC and perhaps other cancers and point to an important role for MAF1 and RNA pol III-mediated transcription in chemosensitivity and apoptosis.

Asunto(s)

Antibióticos Antineoplásicos/farmacología , Carcinoma Hepatocelular/tratamiento farmacológico , Doxorrubicina/farmacología , Neoplasias Hepáticas/tratamiento farmacológico , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteínas Represoras/antagonistas & inhibidores , Ubiquitina/metabolismo , Animales , Apoptosis/efectos de los fármacos , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Ciclo Celular/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Ratones , Ratones Noqueados , Fosforilación/efectos de los fármacos , Proteínas Represoras/deficiencia , Proteínas Represoras/metabolismo

RESUMEN

RNA polymerase (pol) III transcribes a variety of small untranslated RNAs involved in transcription, RNA processing, and translation. RNA pol III and its components are altered in various human developmental disorders, yet their roles in cell fate determination and development are poorly understood. Here we demonstrate that Maf1, a transcriptional repressor, promotes induction of mouse embryonic stem cells (mESCs) into mesoderm. Reduced Maf1 expression in mESCs and preadipocytes impairs adipogenesis, while ectopic Maf1 expression in Maf1-deficient cells enhances differentiation. RNA pol III repression by chemical inhibition or knockdown of Brf1 promotes adipogenesis. Altered RNA pol III-dependent transcription produces select changes in mRNAs with a significant enrichment of adipogenic gene signatures. Furthermore, RNA pol III-mediated transcription positively regulates long non-coding RNA H19 and Wnt6 expression, established adipogenesis inhibitors. Together, these studies reveal an important and unexpected function for RNA pol III-mediated transcription and Maf1 in mesoderm induction and adipocyte differentiation.

Asunto(s)

Adipocitos/metabolismo , Adipogénesis/genética , ARN Polimerasa III/genética , Proteínas Represoras/genética , Transcripción Genética , Adipocitos/citología , Animales , Factor 1 de Respuesta al Butirato , Diferenciación Celular , Cuerpos Embrioides/citología , Cuerpos Embrioides/metabolismo , Fibroblastos/citología , Fibroblastos/metabolismo , Regulación del Desarrollo de la Expresión Génica , Masculino , Mesodermo/citología , Mesodermo/crecimiento & desarrollo , Mesodermo/metabolismo , Ratones , Ratones Desnudos , Células Madre Embrionarias de Ratones/citología , Células Madre Embrionarias de Ratones/metabolismo , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Cultivo Primario de Células , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , ARN Polimerasa III/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Proteínas de Unión al ARN/antagonistas & inhibidores , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Proteínas Represoras/metabolismo , Transducción de Señal , Proteínas Wnt/genética , Proteínas Wnt/metabolismo

RESUMEN

This retrospective analysis aimed to determine the effects of a maternal viral vaccination program (MVVP; Express Verified) on calf health during the feeding period. In low- and high-risk populations, calves born to dams vaccinated pre-breeding with program products had improved morbidity and mortality outcomes compared with non-program animals.

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Analyse rétrospective de la morbidité dans des parcs d'engraissement et résultats de mortalité chez les veaux nés de mères ayant des antécédents de vaccination connus. Cette analyse rétrospective visait à déterminer les effets d'un programme maternel de vaccination virale (PMVV; Express Verified) sur la santé des veaux durant la période d'allaitement. Dans les populations à risque faible et élevé, les veaux nés de mères vaccinées avant l'accouplement avec des produits de programme présentaient des résultats améliorés de morbidité et de mortalité comparativement aux animaux à l'extérieur du programme.(Traduit par Isabelle Vallières).

Asunto(s)

Complejo Respiratorio Bovino/mortalidad , Enfermedades de los Bovinos/prevención & control , Vacunación/veterinaria , Vacunas Virales/inmunología , Animales , Complejo Respiratorio Bovino/epidemiología , Bovinos , Enfermedades de los Bovinos/inmunología , Femenino , Fiebre/epidemiología , Fiebre/veterinaria , Masculino , Estudios Retrospectivos

RESUMEN

The TATA-binding protein (TBP) plays a central role in eukaryotic gene transcription. Given its key function in transcription initiation, TBP was initially thought to be an invariant protein. However, studies showed that TBP expression is upregulated by oncogenic signaling pathways. Furthermore, depending on the cell type, small increases in cellular TBP amounts can induce changes in cellular growth properties towards a transformed phenotype. Here we sought to identify the specific TBP-regulated gene targets that drive its ability to induce tumorigenesis. Using microarray analysis, our results reveal that increases in cellular TBP concentrations produce selective alterations in gene expression that include an enrichment for genes involved in angiogenesis. Accordingly, we find that TBP levels modulate VEGFA expression, the master regulator of angiogenesis. Increases in cellular TBP amounts induce VEGFA expression and secretion to enhance cell migration and tumor vascularization. TBP mediates changes in VEGFA transcription requiring its recruitment at a hypoxia-insensitive proximal TSS, revealing a mechanism for VEGF regulation under non-stress conditions. The results are clinically relevant as TBP expression is significantly increased in both colon adenocarcinomas as well as adenomas relative to normal tissue. Furthermore, TBP expression is positively correlated with VEGFA expression. Collectively, these studies support the idea that increases in TBP expression contribute to enhanced VEGFA transcription early in colorectal cancer development to drive tumorigenesis.

Asunto(s)

Neoplasias del Colon/genética , Neoplasias del Colon/metabolismo , Regulación Neoplásica de la Expresión Génica , Proteína de Unión a TATA-Box/metabolismo , Factor A de Crecimiento Endotelial Vascular/genética , Sitios de Unión , Movimiento Celular/genética , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Neoplasias del Colon/patología , Expresión Génica , Perfilación de la Expresión Génica , Genes Reporteros , Humanos , Neovascularización Patológica/genética , Neovascularización Patológica/metabolismo , Regiones Promotoras Genéticas , Unión Proteica , ARN Polimerasa II/metabolismo , Proteína de Unión a TATA-Box/genética , Sitio de Iniciación de la Transcripción , Transcriptoma , Factor A de Crecimiento Endotelial Vascular/metabolismo

RESUMEN

PTEN is a critical tumor suppressor whose dysregulation leads to metabolic disease and cancer. How these diseases are linked at a molecular level is poorly understood. Maf1 is a novel PTEN target that connects PTEN's ability to repress intracellular lipid accumulation with its tumor suppressor function. Maf1 represses the expression of rRNAs and tRNAs to restrain biosynthetic capacity and oncogenic transformation. Recent studies demonstrate that Maf1 also controls intracellular lipid accumulation. In animal models, dysregulation of RNA polymerase I- and III-dependent transcription, and subsequent upregulation of rRNAs and tRNAs, leads to altered lipid metabolism and storage. Together these results identify unexpected connections between RNA and lipid metabolism that may help explain the strong epidemiological association between obesity and cancer.

Asunto(s)

Metabolismo de los Lípidos/fisiología , Fosfohidrolasa PTEN/metabolismo , ARN/metabolismo , Proteínas Represoras/metabolismo , Animales , Humanos , Metabolismo de los Lípidos/genética , Fosfohidrolasa PTEN/genética , ARN/genética , Proteínas Represoras/genética

RESUMEN

The aims of this study were to document the extent of nutritional content in U.S. dental hygiene program curricula; identify program directors' opinions, perceptions, and barriers to expanding nutritional content; and evaluate if a proposed nutrition curriculum model would be beneficial. This mixed methods study involved quantitative and qualitative aspects. An invitation letter was sent to all 335 directors of entry-level U.S. dental hygiene programs. In response, 55 directors submitted nutrition course syllabi from their programs (16.4% of the total) for the quantitative analysis. In addition, 14 nutrition instructors and ten program directors were interviewed regarding their perceptions and opinions of nutrition education for dental hygiene students. All aspects of the content analysis results revealed that nutrition content in entry-level dental hygiene programs is diverse. Some programs did not include nutrition content, while others provided oral and systemic nutrition intervention subject matter. Some programs offered multiple clinical nutrition applications and patient contact opportunities while most required none. The interview results disclosed a variety of opinions and perceptions of dental hygienists' role in nutrition. Several interviewees viewed dental hygienists' role in nutrition to be an integral part of patient care, while others indicated no role or providing caries prevention counseling only. Although dental hygienists are expected to provide nutrition assessments and interventions, no standards or standardized competencies exist for nutrition in dental hygiene education. A standardized nutrition model could be beneficial for entry-level programs to ensure dental hygienists possess basic knowledge to perform nutrition assessments and intervention to address Healthy People 2020's intervention initiatives.

Asunto(s)

Curriculum , Higienistas Dentales/educación , Ciencias de la Nutrición/educación , Personal Administrativo , Actitud del Personal de Salud , Consejo , Caries Dental/prevención & control , Dietética/educación , Docentes , Promoción de la Salud , Humanos , Evaluación Nutricional , Relaciones Profesional-Paciente , Estados Unidos

RESUMEN

Maf1 was initially identified as a transcriptional repressor of RNA pol III-transcribed genes, yet little is known about its other potential target genes or its biological function. Here, we show that Maf1 is a key downstream target of PTEN that drives both its tumor suppressor and metabolic functions. Maf1 expression is diminished with loss of PTEN in both mouse models and human cancers. Consistent with its role as a tumor suppressor, Maf1 reduces anchorage-independent growth and tumor formation in mice. PTEN-mediated changes in Maf1 expression are mediated by PTEN acting on PI3K/AKT/FoxO1 signaling, revealing a new pathway that regulates RNA pol III-dependent genes. This regulatory event is biologically relevant as diet-induced PI3K activation reduces Maf1 expression in mouse liver. We further identify lipogenic enzymes as a new class of Maf1-regulated genes whereby Maf1 occupancy at the FASN promoter opposes SREBP1c-mediated transcription activation. Consistent with these findings, Maf1 inhibits intracellular lipid accumulation and increasing Maf1 expression in mouse liver abrogates diet-mediated induction of lipogenic enzymes and triglycerides. Together, these results establish a new biological role for Maf1 as a downstream effector of PTEN/PI3K signaling and reveal that Maf1 is a key element by which this pathway co-regulates lipid metabolism and oncogenesis.

Asunto(s)

Carcinogénesis , Metabolismo de los Lípidos/genética , Fosfohidrolasa PTEN/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Represoras/metabolismo , Animales , Línea Celular Tumoral , Inmunoprecipitación de Cromatina , Proteína Forkhead Box O1 , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Células Hep G2 , Humanos , Inmunohistoquímica , Masculino , Ratones , Ratones Endogámicos C57BL , Neoplasias/complicaciones , Neoplasias/genética , Obesidad/complicaciones , Obesidad/genética , Fosfohidrolasa PTEN/genética , Fosfatidilinositol 3-Quinasas/genética , Regiones Promotoras Genéticas , Proteínas Represoras/genética , Transducción de Señal

RESUMEN

Maf1 is a conserved repressor of RNA polymerase (Pol) III transcription; however, its physiological role in the context of a multicellular organism is not well understood. Here, we show that C. elegans MAFR-1 is functionally orthologous to human Maf1, represses the expression of both RNA Pol III and Pol II transcripts, and mediates organismal fecundity and lipid homeostasis. MAFR-1 impacts lipid transport by modulating intestinal expression of the vitellogenin family of proteins, resulting in cell-nonautonomous defects in the developing reproductive system. MAFR-1 levels inversely correlate with stored intestinal lipids, in part by influencing the expression of the lipogenesis enzymes fasn-1/FASN and pod-2/ACC1. Animals fed a high carbohydrate diet exhibit reduced mafr-1 expression and mutations in the insulin signaling pathway genes daf-18/PTEN and daf-16/FoxO abrogate the lipid storage defects associated with deregulated mafr-1 expression. Our results reveal physiological roles for mafr-1 in regulating organismal lipid homeostasis, which ensure reproductive success.

Asunto(s)

Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Fertilidad , Metabolismo de los Lípidos , Proteínas Represoras/metabolismo , Acetiltransferasas/genética , Acetiltransferasas/metabolismo , Animales , Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiología , Proteínas de Caenorhabditis elegans/genética , Acido Graso Sintasa Tipo I/genética , Acido Graso Sintasa Tipo I/metabolismo , Homeostasis , Mucosa Intestinal/metabolismo , ARN Polimerasa I/genética , ARN Polimerasa I/metabolismo , ARN Polimerasa III/genética , ARN Polimerasa III/metabolismo , Proteínas Represoras/genética , Sistema Urogenital/crecimiento & desarrollo , Sistema Urogenital/metabolismo , Sistema Urogenital/fisiología , Vitelogeninas/genética , Vitelogeninas/metabolismo

RESUMEN

Tissue regeneration diminishes with age, concurrent with declining hormone levels including growth factors such as insulin-like growth factor-1 (IGF-1). We investigated the molecular basis for such decline in pancreatic ß-cells where loss of proliferation occurs early in age and is proposed to contribute to the pathogenesis of diabetes. We studied the regeneration capacity of ß-cells in mouse model where PI3K/AKT pathway downstream of insulin/IGF-1 signaling is upregulated by genetic deletion of Pten (phosphatase and tensin homologue deleted on chromosome 10) specifically in insulin-producing cells. In this model, PTEN loss prevents the decline in proliferation capacity in aged ß-cells and restores the ability of aged ß-cells to respond to injury-induced regeneration. Using several animal and cell models where we can manipulate PTEN expression, we found that PTEN blocks cell cycle re-entry through a novel pathway leading to an increase in p16(ink4a), a cell cycle inhibitor characterized for its role in cellular senescence/aging. A downregulation in p16(ink4a) occurs when PTEN is lost as a result of cyclin D1 induction and the activation of E2F transcription factors. The activation of E2F transcriptional factors leads to methylation of p16(ink4a) promoter, an event that is mediated by the upregulation of polycomb protein, Ezh2. These analyses establish a novel PTEN/cyclin D1/E2F/Ezh2/p16(ink4a) signaling network responsible for the aging process and provide specific evidence for a molecular paradigm that explain how decline in growth factor signals such as IGF-1 (through PTEN/PI3K signaling) may control regeneration and the lack thereof in aging cells.

Asunto(s)

Ciclo Celular , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patología , Fosfohidrolasa PTEN/metabolismo , Envejecimiento/patología , Animales , Proliferación Celular , Ciclina D1/metabolismo , Inhibidor p27 de las Quinasas Dependientes de la Ciclina/metabolismo , Metilación de ADN/genética , Regulación hacia Abajo/genética , Proteína Potenciadora del Homólogo Zeste 2 , Eliminación de Gen , Humanos , Ratones , Fosfohidrolasa PTEN/deficiencia , Complejo Represivo Polycomb 2/genética , Complejo Represivo Polycomb 2/metabolismo , Transducción de Señal , Regulación hacia Arriba/genética

RESUMEN

RNA polymerase (pol) III transcribes genes that determine biosynthetic capacity. Induction of these genes is required for oncogenic transformation. The transcriptional repressor, Maf1, plays a central role in the repression of these and other genes that promote oncogenesis. Our studies identify an important new role for SUMOylation in repressing RNA pol III-dependent transcription. We show that a key mechanism by which this occurs is through small ubiquitin-like modifier (SUMO) modification of Maf1 by both SUMO1 and SUMO2. Mutation of each lysine residue revealed that Lys-35 is the major SUMOylation site on Maf1 and that the deSUMOylase, SENP1, is responsible for controlling Maf1K35 SUMOylation. SUMOylation of Maf1 is unaffected by rapamycin inhibition of mammalian target of rapamycin (mTOR) and mTOR-dependent Maf1 phosphorylation. By preventing SUMOylation at Lys-35, Maf1 is impaired in its ability to both repress transcription and suppress colony growth. Although SUMOylation does not alter Maf1 subcellular localization, Maf1K35R is defective in its ability to associate with RNA pol III. This impairs Maf1 recruitment to tRNA gene promoters and its ability to facilitate the dissociation of RNA pol III from these promoters. These studies identify a novel role for SUMOylation in controlling Maf1 and RNA pol III-mediated transcription. Given the emerging roles of SENP1, Maf1, and RNA pol III transcription in oncogenesis, our studies support the idea that deSUMOylation of Maf1 and induction of its gene targets play a critical role in cancer development.

Asunto(s)

Endopeptidasas/metabolismo , Regulación Neoplásica de la Expresión Génica , ARN Polimerasa III/metabolismo , Proteínas Represoras/metabolismo , Proteínas Modificadoras Pequeñas Relacionadas con Ubiquitina/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Células COS , Línea Celular Tumoral , Proliferación Celular , Chlorocebus aethiops , Cisteína Endopeptidasas , Células HEK293 , Humanos , Lisina/química , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Neoplasias/metabolismo , Procesamiento Proteico-Postraduccional , Factores de Transcripción/metabolismo , Transcripción Genética

RESUMEN

VPS4B, an AAA ATPase (ATPase associated with various cellular activities), participates in vesicular trafficking and autophagosome maturation in mammalian cells. In solid tumors, hypoxia is a common feature and an indicator of poor treatment outcome. Our studies demonstrate that exogenous or endogenous (assessed with anchorage-independent three-dimensional multicellular spheroid culture) hypoxia induces VPS4B downregulation by the ubiquitin-proteasome system. Inhibition of VPS4B function by short hairpin VPS4B (sh-VPS4B) or expression of dominant negative VPS4B(E235Q) promotes anchorage-independent breast cancer cell growth and resistance to gefitinib, U0126, and genotoxicity. Biochemically, hyperactivation of epidermal growth factor receptor (EGFR), a receptor tyrosine kinase essential for cell proliferation and survival, accompanied by increased EGFR accumulation and altered intracellular compartmentalization, is observed in cells with compromised VPS4B. Furthermore, enhanced FOS/JUN induction and AP-1 promoter activation are noted in EGF-treated cells with VPS4B knockdown. However, VPS4B depletion does not affect EGFRvIII stability or its associated signaling. An inverse correlation between VPS4B expression and EGFR abundance is observed in breast tumors, and high-grade or recurrent breast carcinomas exhibit lower VPS4B expression. Together, our findings highlight a potentially critical role of VPS4B downregulation or chronic-hypoxia-induced VPS4B degradation in promoting tumor progression, unveiling a nongenomic mechanism for EGFR overproduction in human breast cancer.

Asunto(s)

Adenosina Trifosfatasas/metabolismo , Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Receptores ErbB/metabolismo , Transducción de Señal , ATPasas Asociadas con Actividades Celulares Diversas , Adenosina Trifosfatasas/genética , Animales , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Hipoxia de la Célula , Línea Celular , Línea Celular Tumoral , Regulación hacia Abajo , Complejos de Clasificación Endosomal Requeridos para el Transporte/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Fosforilación , ARN Mensajero/genética , Ratas , Esferoides Celulares

RESUMEN

This study examined whether parent-youth dyads participating in the Strengthening Families Program 10-14 (SFP 10-14) would demonstrate greater postprogram family cohesion, communication, involvement, and supervision and if youth would report less alcohol, tobacco, and other drugs involvement in contrast to a comparison group. From 16 randomly selected schools, we recruited 167 parent-youth dyads: 86 from intervention and 81 from comparison schools. The intention-to-treat analysis found one significant change in family environment. Considering dose, it was found that among dyads receiving a full dose, all the outcomes were in the expected direction and effect sizes were moderate. Among dyads receiving a partial dose, 10 of 18 outcomes were in the direction opposite that expected. Youth participation in alcohol, tobacco, and other drugs was very low and did not differ postprogram. Although the expected outcomes were not realized, findings descriptive of dosage effects make a valuable contribution to the field. Study of factors that distinguish intervention completers from noncompleters is recommended.

Asunto(s)

Familia , Relaciones Padres-Hijo , Adolescente , Adulto , Femenino , Humanos , Masculino , Trastornos Relacionados con Sustancias/prevención & control

RESUMEN

Effective management and conservation of species, subspecies, or ecotypes require an understanding of how populations are structured in space. We used satellite-tracking locations and hierarchical and fuzzy clustering to quantify subpopulations within the behaviorally different barren-ground caribou (Rangifer tarandus groenlandicus), Dolphin and Union island caribou (R. t. groenlandicus x pearyi), and boreal (R. t. caribou) caribou ecotypes in the Northwest Territories and Nunavut, Canada. Using a novel approach, we verified that the previously recognized Cape Bathurst, Bluenose-West, Bluenose-East, Bathurst, Beverly, Qamanirjuaq, and Lorillard barren-ground subpopulations were robust and that the Queen Maude Gulf and Wager Bay barren-ground subpopulations were organized as individuals. Dolphin and Union island and boreal caribou formed one and two distinct subpopulation, respectively, and were organized as individuals. Robust subpopulations were structured by strong annual spatial affiliation among females; subpopulations organized as individuals were structured by migratory connectivity, barriers to movement, and/or habitat discontinuity. One barren-ground subpopulation used two calving grounds, and one calving ground was used by two barren-ground subpopulations, indicating that these caribou cannot be reliably assigned to subpopulations solely by calving-ground use. They should be classified by annual spatial affiliation among females. Annual-range size and path lengths varied significantly among ecotypes, including mountain woodland caribou (R. t. caribou), and reflected behavioral differences. An east-west cline in annual-range sizes and path lengths among migratory barren-ground subpopulations likely reflected differences in subpopulation size and habitat conditions and further supported the subpopulation structure identified.

Asunto(s)

Ciervos/fisiología , Ecosistema , Migración Animal , Animales , Regiones Árticas , Canadá , Demografía , Femenino , Sistemas de Información Geográfica , Modelos Biológicos , Conducta Social

RESUMEN

Chronic alcohol consumption is associated with steatohepatitis and cirrhosis, enhancing the risk for hepatocellular carcinoma. RNA polymerase (pol) III transcribes a variety of small, untranslated RNAs, including tRNAs and 5S rRNAs, which determine the biosynthetic capacity of cells. Increased RNA pol III-dependent transcription, observed in transformed cells and human tumors, is required for oncogenic transformation. Given that alcohol consumption increases risk for liver cancer, we examined whether alcohol regulates this class of genes. Ethanol induces RNA pol III-dependent transcription in both HepG2 cells and primary mouse hepatocytes in a manner that requires ethanol metabolism and the activation of JNK1. This regulatory event is mediated, at least in part, through the ability of ethanol to induce expression of the TFIIIB components, Brf1, and the TATA-binding protein (TBP). Induction of TBP, Brf1, and RNA pol III-dependent gene expression is driven by enhanced c-Jun expression. Ethanol promotes a marked increase in the direct recruitment of c-Jun to TBP, Brf1, and tRNA gene promoters. Chronic alcohol administration in mice leads to enhanced expression of TBP, Brf1, tRNA, and 5S rRNA gene transcription in the liver. These alcohol-dependent increases are more pronounced in transgenic animals that express the HCV NS5A protein that display increased incidence of liver tumors. Together, these results identify a new class of genes that are regulated by alcohol through the co-regulation of TFIIIB components and define a central role for c-Jun in this process.

Asunto(s)

Depresores del Sistema Nervioso Central/farmacología , Etanol/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Proteínas Nucleares/biosíntesis , Proteínas Proto-Oncogénicas c-jun/metabolismo , ARN Polimerasa III/metabolismo , Proteínas de Unión al ARN/biosíntesis , Factores Asociados con la Proteína de Unión a TATA/biosíntesis , Proteína de Unión a TATA-Box/metabolismo , Animales , Factor 1 de Respuesta al Butirato , Carcinoma Hepatocelular/inducido químicamente , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Transformación Celular Neoplásica/inducido químicamente , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Depresores del Sistema Nervioso Central/efectos adversos , Activación Enzimática/efectos de los fármacos , Activación Enzimática/genética , Etanol/efectos adversos , Hígado Graso/inducido químicamente , Hígado Graso/genética , Hígado Graso/metabolismo , Regulación de la Expresión Génica/genética , Células Hep G2 , Humanos , Cirrosis Hepática Alcohólica/genética , Cirrosis Hepática Alcohólica/metabolismo , Neoplasias Hepáticas/inducido químicamente , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , MAP Quinasa Quinasa 4/genética , MAP Quinasa Quinasa 4/metabolismo , Ratones , Ratones Transgénicos , Proteínas Nucleares/genética , Proteínas Proto-Oncogénicas c-jun/genética , ARN Polimerasa III/genética , ARN Ribosómico 5S/biosíntesis , ARN Ribosómico 5S/genética , ARN de Transferencia/biosíntesis , ARN de Transferencia/genética , Proteínas de Unión al ARN/genética , Elementos de Respuesta/genética , Factores Asociados con la Proteína de Unión a TATA/genética , Proteína de Unión a TATA-Box/genética , Transcripción Genética/efectos de los fármacos , Transcripción Genética/genética , Proteínas no Estructurales Virales/biosíntesis , Proteínas no Estructurales Virales/genética

RESUMEN

RNA polymerase (pol) III-dependent transcription is subject to stringent regulation by tumor suppressors and oncogenic proteins and enhanced RNA pol III transcription is essential for cellular transformation and tumorigenesis. Since the c-Jun N-terminal kinases (JNKs) display both oncogenic and tumor suppressor properties, the roles of these proteins in regulating RNA pol III transcription were examined. In both mouse and human cells, loss or reduction in JNK1 expression represses RNA pol III transcription. In contrast, loss or reduction in JNK2 expression induces transcription. The JNKs coordinately regulate expression of all 3 TFIIIB subunits. While JNK1 positively regulates TBP expression, the RNA pol III-specific factors, Brf1 and Bdp1, JNK2 negatively regulates their expression. Brf1 is coregulated with TBP through the JNK target, Elk-1. Reducing Elk-1 expression decreases Brf1 expression. Decreasing JNK1 expression reduces Elk-1 occupancy at the Brf1 promoter, while decreasing JNK2 expression enhances recruitment of Elk-1 to the Brf1 promoter. In contrast, regulation of Bdp1 occurs through JNK-mediated alterations in TBP expression. Altered TBP expression mimics the effect of reduced JNK1 or JNK2 levels on Bdp1 expression. Decreasing JNK1 expression reduces the occupancy of TBP at the Bdp1 promoter, while decreasing JNK2 expression enhances recruitment of TBP to the Bdp1 promoter. Together, these results provide a molecular mechanism for regulating RNA pol III transcription through the coordinate control of TFIIIB subunit expression and elucidate opposing functions for the JNKs in regulating a large class of genes that dictate the biosynthetic capacity of cells.

Asunto(s)

Proteína Quinasa 8 Activada por Mitógenos/fisiología , Proteína Quinasa 9 Activada por Mitógenos/fisiología , ARN Polimerasa III/fisiología , Factor de Transcripción TFIIIB/genética , Transcripción Genética , Regulación de la Expresión Génica , Humanos , Regiones Promotoras Genéticas , Subunidades de Proteína , Proteínas Tirosina Fosfatasas no Receptoras/genética , Factores Asociados con la Proteína de Unión a TATA/genética , Proteína de Unión a TATA-Box/genética , Proteína de Unión a TATA-Box/metabolismo , Proteína Elk-1 con Dominio ets/metabolismo