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1.
J Cell Sci ; 137(4)2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38240353

RESUMO

The tumour suppressor, Lethal (2) giant larvae [Lgl; also known as L(2)gl], is an evolutionarily conserved protein that was discovered in the vinegar fly Drosophila, where its depletion results in tissue overgrowth and loss of cell polarity. Lgl links cell polarity and tissue growth through regulation of the Notch and the Hippo signalling pathways. Lgl regulates the Notch pathway by inhibiting V-ATPase activity via Vap33. How Lgl regulates the Hippo pathway was unclear. In this current study, we show that V-ATPase activity inhibits the Hippo pathway, whereas Vap33 acts to activate Hippo signalling. Vap33 physically and genetically interacts with the actin cytoskeletal regulators RtGEF (Pix) and Git, which also bind to the Hippo protein (Hpo) and are involved in the activation of the Hippo pathway. Additionally, we show that the ADP ribosylation factor Arf79F (Arf1), which is a Hpo interactor, is involved in the inhibition of the Hippo pathway. Altogether, our data suggest that Lgl acts via Vap33 to activate the Hippo pathway by a dual mechanism: (1) through interaction with RtGEF, Git and Arf79F, and (2) through interaction and inhibition of the V-ATPase, thereby controlling epithelial tissue growth.


Assuntos
Proteínas de Drosophila , Neoplasias , Animais , Adenosina Trifosfatases/metabolismo , Polaridade Celular , Drosophila/metabolismo , Drosophila melanogaster , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Via de Sinalização Hippo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Proteínas Supressoras de Tumor/metabolismo
2.
BMC Health Serv Res ; 21(1): 22, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33407442

RESUMO

BACKGROUND: In sub-Saharan Africa, there is dearth of trained laboratorians and strengthened laboratory systems to provide adequate and quality laboratory services for enhanced HIV control. In response to this challenge, in 2007, the African Centre for Integrated Laboratory Training (ACILT) was established in South Africa with a mission to train staffs from countries with high burdens of diseases in skills needed to strengthen sustainable laboratory systems. This study was undertaken to assess the transference of newly gained knowledge and skills to other laboratory staff, and to identify enabling and obstructive factors to their implementation. METHODS: We used Kirkpatrick model to determine training effectiveness by assessing the transference of newly gained knowledge and skills to participant's work environment, along with measuring enabling and obstructive factors. In addition to regular course evaluations at ACILT (pre and post training), in 2015 we sent e-questionnaires to 867 participants in 43 countries for course participation between 2008 and 2014. Diagnostics courses included Viral Load, and systems strengthening included strategic planning and Biosafety and Biosecurity. SAS v9.44 and Excel were used to analyze retrospective de-identified data collected at six months pre and post-training. RESULTS: Of the 867 participants, 203 (23.4%) responded and reported average improvements in accuracy and timeliness in Viral Load programs and to systems strengthening. For Viral Load testing, frequency of corrective action for unsatisfactory proficiency scores improved from 57 to 91%, testing error rates reduced from 12.9% to 4.9%; 88% responders contributed to the first national strategic plan development and 91% developed strategies to mitigate biosafety risks in their institutions. Key enabling factors were team and management support, and key obstructive factors included insufficient resources and staff's resistance to change. CONCLUSIONS: Training at ACILT had a documented positive impact on strengthening the laboratory capacity and laboratory workforce and substantial cost savings. ACILT's investment produced a multiplier effect whereby national laboratory systems, personnel and leadership reaped training benefits. This laboratory training centre with a global clientele contributed to improve existing laboratory services, systems and networks for the HIV epidemic and is now being leveraged for COVID-19 testing that has infected 41,332,899 people globally.


Assuntos
Epidemias/prevenção & controle , Infecções por HIV/prevenção & controle , Laboratórios/organização & administração , Pessoal de Laboratório/educação , África Subsaariana/epidemiologia , Teste para COVID-19 , Serviços de Laboratório Clínico , Infecções por HIV/epidemiologia , Teste de HIV , Pesquisa sobre Serviços de Saúde , Humanos , Estudos Retrospectivos
3.
Mol Neurobiol ; 58(4): 1769-1781, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33387303

RESUMO

We have previously shown that the expression of nicotinamide N-methyltransferase (NNMT) is significantly increased in the brains of patients who have died of Parkinson's disease (PD). In this study, we have compared the expression of NNMT in post-mortem medial temporal lobe, hippocampus and cerebellum of 10 Alzheimer's disease (AD) and 9 non-disease control subjects using a combination of quantitative Western blotting, immunohistochemistry and dual-label confocal microscopy coupled with quantitative analysis of colocalisation. NNMT was detected as a single protein of 29 kDa in both AD and non-disease control brains, which was significantly increased in AD medial temporal lobe compared to non-disease controls (7.5-fold, P < 0.026). There was no significant difference in expression in the cerebellum (P = 0.91). NNMT expression in AD medial temporal lobe and hippocampus was present in cholinergic neurones with no glial localisation. Cell-type expression was identical in both non-disease control and AD tissues. These results are the first to show, in a proof-of-concept study using a small patient cohort, that NNMT protein expression is increased in the AD brain and is present in neurones which degenerate in AD. These results suggest that the elevation of NNMT may be a common feature of many neurodegenerative diseases. Confirmation of this overexpression using a larger AD patient cohort will drive the future development of NNMT-targetting therapeutics which may slow or stop the disease pathogenesis, in contrast to current therapies which solely address AD symptoms.


Assuntos
Doença de Alzheimer/enzimologia , Nicotinamida N-Metiltransferase/metabolismo , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Estudos de Casos e Controles , Cerebelo/enzimologia , Cerebelo/patologia , Feminino , Hipocampo/enzimologia , Hipocampo/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Neurônios/enzimologia , Neurônios/patologia , Lobo Temporal/enzimologia , Lobo Temporal/patologia
4.
Genetics ; 216(1): 135-144, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32675276

RESUMO

As juvenile animals grow, their behavior, physiology, and development need to be matched to environmental conditions to ensure they survive to adulthood. However, we know little about how behavior and physiology are integrated with development to achieve this outcome. Neuropeptides are prime candidates for achieving this due to their well-known signaling functions in controlling many aspects of behavior, physiology, and development in response to environmental cues. In the growing Drosophila larva, while several neuropeptides have been shown to regulate feeding behavior, and a handful to regulate growth, it is unclear if any of these play a global role in coordinating feeding behavior with developmental programs. Here, we demonstrate that Neuropeptide F Receptor (NPFR), best studied as a conserved regulator of feeding behavior from insects to mammals, also regulates development in Drosophila Knocking down NPFR in the prothoracic gland, which produces the steroid hormone ecdysone, generates developmental delay and an extended feeding period, resulting in increased body size. We show that these effects are due to decreased ecdysone production, as these animals have reduced expression of ecdysone biosynthesis genes and lower ecdysone titers. Moreover, these phenotypes can be rescued by feeding larvae food supplemented with ecdysone. Further, we show that NPFR negatively regulates the insulin signaling pathway in the prothoracic gland to achieve these effects. Taken together, our data demonstrate that NPFR signaling plays a key role in regulating animal development, and may, thus, play a global role in integrating feeding behavior and development in Drosophila.


Assuntos
Tamanho Corporal , Proteínas de Drosophila/genética , Estágios do Ciclo de Vida/genética , Receptores de Neuropeptídeos/genética , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Ecdisona/metabolismo , Comportamento Alimentar , Receptores de Neuropeptídeos/metabolismo , Transdução de Sinais
5.
Development ; 147(11)2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32527935

RESUMO

Here, we report novel tumour suppressor activity for the Drosophila Argonaute family RNA-binding protein AGO1, a component of the miRNA-dependent RNA-induced silencing complex (RISC). The mechanism for growth inhibition does not, however, involve canonical roles as part of the RISC; rather, AGO1 controls cell and tissue growth by functioning as a direct transcriptional repressor of the master regulator of growth, Myc. AGO1 depletion in wing imaginal discs drives a significant increase in ribosome biogenesis, nucleolar expansion and cell growth in a manner dependent on Myc abundance. Moreover, increased Myc promoter activity and elevated Myc mRNA in AGO1-depleted animals requires RNA polymerase II transcription. Further support for transcriptional AGO1 functions is provided by physical interaction with the RNA polymerase II transcriptional machinery (chromatin remodelling factors and Mediator Complex), punctate nuclear localisation in euchromatic regions and overlap with Polycomb Group transcriptional silencing loci. Moreover, significant AGO1 enrichment is observed on the Myc promoter and AGO1 interacts with the Myc transcriptional activator Psi. Together, our data show that Drosophila AGO1 functions outside of the RISC to repress Myc transcription and inhibit developmental cell and tissue growth.This article has an associated 'The people behind the papers' interview.


Assuntos
Proteínas Argonautas/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Fatores de Transcrição/metabolismo , Animais , Animais Geneticamente Modificados/metabolismo , Proteínas Argonautas/antagonistas & inibidores , Proteínas Argonautas/genética , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/genética , Drosophila/crescimento & desenvolvimento , Proteínas de Drosophila/antagonistas & inibidores , Proteínas de Drosophila/genética , Larva/metabolismo , MicroRNAs/metabolismo , Mutagênese Sítio-Dirigida , Regiões Promotoras Genéticas , Interferência de RNA , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/antagonistas & inibidores , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Ribossomos/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/genética , Transcrição Gênica , Asas de Animais/crescimento & desenvolvimento , Asas de Animais/fisiologia
6.
Int J Mol Sci ; 19(12)2018 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-30567377

RESUMO

Many of the links between diet and cancer are controversial and over simplified. To date, human epidemiological studies consistently reveal that patients who suffer diet-related obesity and/or type II diabetes have an increased risk of cancer, suffer more aggressive cancers, and respond poorly to current therapies. However, the underlying molecular mechanisms that increase cancer risk and decrease the response to cancer therapies in these patients remain largely unknown. Here, we review studies in mouse cancer models in which either dietary or genetic manipulation has been used to model obesity and/or type II diabetes. These studies demonstrate an emerging role for the conserved insulin and insulin-like growth factor signaling pathways as links between diet and cancer progression. However, these models are time consuming to develop and expensive to maintain. As the world faces an epidemic of obesity and type II diabetes we argue that the development of novel animal models is urgently required. We make the case for Drosophila as providing an unparalleled opportunity to combine dietary manipulation with models of human metabolic disease and cancer. Thus, combining diet and cancer models in Drosophila can rapidly and significantly advance our understanding of the conserved molecular mechanisms that link diet and diet-related metabolic disorders to poor cancer patient prognosis.


Assuntos
Diabetes Mellitus Tipo 2/genética , Dieta , Neoplasias/genética , Obesidade/genética , Animais , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/patologia , Modelos Animais de Doenças , Drosophila , Humanos , Camundongos , Neoplasias/complicações , Neoplasias/patologia , Obesidade/complicações , Obesidade/patologia
7.
Sci Signal ; 11(533)2018 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-29871910

RESUMO

Epithelial cell polarity is linked to the control of tissue growth and tumorigenesis. The tumor suppressor and cell polarity protein lethal-2-giant larvae (Lgl) promotes Hippo signaling and inhibits Notch signaling to restrict tissue growth in Drosophila melanogaster Notch signaling is greater in lgl mutant tissue than in wild-type tissue because of increased acidification of endosomal vesicles, which promotes the proteolytic processing and activation of Notch by γ-secretase. We showed that the increased Notch signaling and tissue growth defects of lgl mutant tissue depended on endosomal vesicle acidification mediated by the vacuolar adenosine triphosphatase (V-ATPase). Lgl promoted the activity of the V-ATPase by interacting with Vap33 (VAMP-associated protein of 33 kDa). Vap33 physically and genetically interacted with Lgl and V-ATPase subunits and repressed V-ATPase-mediated endosomal vesicle acidification and Notch signaling. Vap33 overexpression reduced the abundance of the V-ATPase component Vha44, whereas Lgl knockdown reduced the binding of Vap33 to the V-ATPase component Vha68-3. Our data indicate that Lgl promotes the binding of Vap33 to the V-ATPase, thus inhibiting V-ATPase-mediated endosomal vesicle acidification and thereby reducing γ-secretase activity, Notch signaling, and tissue growth. Our findings implicate the deregulation of Vap33 and V-ATPase activity in polarity-impaired epithelial cancers.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Endossomos/metabolismo , Proteínas de Membrana/metabolismo , Transdução de Sinais , Proteínas Supressoras de Tumor/metabolismo , ATPases Vacuolares Próton-Translocadoras/metabolismo , Ácidos/metabolismo , Animais , Proteínas de Transporte/genética , Polaridade Celular , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Epitélio/crescimento & desenvolvimento , Epitélio/metabolismo , Olho/crescimento & desenvolvimento , Olho/metabolismo , Feminino , Proteínas de Membrana/genética , Receptores Notch/genética , Receptores Notch/metabolismo , Proteínas Supressoras de Tumor/genética , ATPases Vacuolares Próton-Translocadoras/genética , Vacúolos/metabolismo
8.
J Neurol Neurosurg Psychiatry ; 89(12): 1320-1323, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29661925

RESUMO

OBJECTIVES: After 20 years of data collection, pregnancy registers have informed prescribing practice. Various populations show trends for a reduction in valproate prescribing, which is associated with an increased risk of anatomical teratogenesis and neurodevelopmental effects in those exposed in utero. Our aim was to determine if any shifts in prescribing trends have occurred in the UK and Ireland Epilepsy and Pregnancy Register cohort and to assess if there had been any change in the overall major congenital malformation (MCM) rate over time. METHODS: The UK and Ireland Epilepsy and Pregnancy Register, a prospective, observational, registration and follow-up study established in 1996, was used to determine the changes in antiepileptic drugs (AEDs) utilised during pregnancy and the MCM rate between 1996 and 2016. Linear regression analysis was used to assess changes in AED utilisation, and Poisson regression was used for the analysis of trends in the MCM rates. RESULTS: Outcome data for 9247 pregnancies showed a stable percentage of monotherapy to polytherapy prescribing habits over time. After Bonferroni correction, statistically significant (p<0.003) changes were found in monotherapy prescribing with increases in lamotrigine and levetiracetam and decreases in valproate and carbamazepine use. Between 1996 and 2016, the total MCM rate showed a 2.1% reduction per year (incidence risk ratio 0.979 (95% CIs 0.956 to 1.002) but Poisson regression analysis showed that this was not statistically significant p=0.08). CONCLUSION: Significant changes are seen in the prescribing habits in this cohort over 20 years, but a statistically significant change in the MCM rate was not detected. This work should be replicated on a larger scale to determine if significant changes are occurring in the MCM rate, which would allow a robust economic estimate of the benefits of improvements in prescribing practice and the personal effect of such changes.


Assuntos
Anormalidades Induzidas por Medicamentos/epidemiologia , Anticonvulsivantes/efeitos adversos , Uso de Medicamentos/tendências , Resultado da Gravidez/epidemiologia , Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Feminino , Humanos , Incidência , Irlanda/epidemiologia , Gravidez , Estudos Prospectivos , Sistema de Registros/estatística & dados numéricos , Reino Unido/epidemiologia
9.
Biol Open ; 7(1)2018 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-29361610

RESUMO

Drosophila lethal giant larvae (lgl) encodes a conserved tumor suppressor with established roles in cell polarity, asymmetric division, and proliferation control. Lgl's human orthologs, HUGL1 and HUGL2, are altered in human cancers, however, its mechanistic role as a tumor suppressor remains poorly understood. Based on a previously established connection between Lgl and Fragile X protein (FMRP), a miRNA-associated translational regulator, we hypothesized that Lgl may exert its role as a tumor suppressor by interacting with the miRNA pathway. Consistent with this model, we found that lgl is a dominant modifier of Argonaute1 overexpression in the eye neuroepithelium. Using microarray profiling we identified a core set of ten miRNAs that are altered throughout tumorigenesis in Drosophila lgl mutants. Among these are several miRNAs previously linked to human cancers including miR-9a, which we found to be downregulated in lgl neuroepithelial tissues. To determine whether miR-9a can act as an effector of Lgl in vivo, we overexpressed it in the context of lgl knock-down by RNAi and found it able to reduce the overgrowth phenotype caused by Lgl loss in epithelia. Furthermore, cross-comparisons between miRNA and mRNA profiling in lgl mutant tissues and human breast cancer cells identified thrombospondin (tsp) as a common factor altered in both fly and human breast cancer tumorigenesis models. Our work provides the first evidence of a functional connection between Lgl and the miRNA pathway, demonstrates that miR-9a mediates Lgl's role in restricting epithelial proliferation, and provides novel insights into pathways controlled by Lgl during tumor progression.

10.
G3 (Bethesda) ; 7(8): 2497-2509, 2017 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-28611255

RESUMO

In both Drosophila melanogaster and mammalian systems, epithelial structure and underlying cell polarity are essential for proper tissue morphogenesis and organ growth. Cell polarity interfaces with multiple cellular processes that are regulated by the phosphorylation status of large protein networks. To gain insight into the molecular mechanisms that coordinate cell polarity with tissue growth, we screened a boutique collection of RNAi stocks targeting the kinome for their capacity to modify Drosophila "cell polarity" eye and wing phenotypes. Initially, we identified kinase or phosphatase genes whose depletion modified adult eye phenotypes associated with the manipulation of cell polarity complexes (via overexpression of Crb or aPKC). We next conducted a secondary screen to test whether these cell polarity modifiers altered tissue overgrowth associated with depletion of Lgl in the wing. These screens identified Hippo, Jun kinase (JNK), and Notch signaling pathways, previously linked to cell polarity regulation of tissue growth. Furthermore, novel pathways not previously connected to cell polarity regulation of tissue growth were identified, including Wingless (Wg/Wnt), Ras, and lipid/Phospho-inositol-3-kinase (PI3K) signaling pathways. Additionally, we demonstrated that the "nutrient sensing" kinases Salt Inducible Kinase 2 and 3 (SIK2 and 3) are potent modifiers of cell polarity phenotypes and regulators of tissue growth. Overall, our screen has revealed novel cell polarity-interacting kinases and phosphatases that affect tissue growth, providing a platform for investigating molecular mechanisms coordinating cell polarity and tissue growth during development.


Assuntos
Polaridade Celular/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Epistasia Genética , Epitélio/metabolismo , Genes de Insetos , Testes Genéticos , Interferência de RNA , Animais , Proteínas de Drosophila/metabolismo , Feminino , Ontologia Genética , Genes Modificadores , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Tamanho do Órgão/genética , Transdução de Sinais/genética , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Asas de Animais/anatomia & histologia
11.
Nucleic Acids Res ; 44(16): 7646-58, 2016 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-27207882

RESUMO

Despite two decades of research, the major function of FBP-family KH domain proteins during animal development remains controversial. The literature is divided between RNA processing and transcriptional functions for these single stranded nucleic acid binding proteins. Using Drosophila, where the three mammalian FBP proteins (FBP1-3) are represented by one ortholog, Psi, we demonstrate the primary developmental role is control of cell and tissue growth. Co-IP-mass spectrometry positioned Psi in an interactome predominantly comprised of RNA Polymerase II (RNA Pol II) transcriptional machinery and we demonstrate Psi is a potent transcriptional activator. The most striking interaction was between Psi and the transcriptional mediator (MED) complex, a known sensor of signaling inputs. Moreover, genetic manipulation of MED activity modified Psi-dependent growth, which suggests Psi interacts with MED to integrate developmental growth signals. Our data suggest the key target of the Psi/MED network in controlling developmentally regulated tissue growth is the transcription factor MYC. As FBP1 has been implicated in controlling expression of the MYC oncogene, we predict interaction between MED and FBP1 might also have implications for cancer initiation and progression.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Complexo Mediador/metabolismo , Morfogênese , Proteínas Proto-Oncogênicas c-myc/metabolismo , Animais , Drosophila melanogaster/citologia , Drosophila melanogaster/genética , Técnicas de Silenciamento de Genes , Células HeLa , Humanos , Proteínas Nucleares , Regiões Promotoras Genéticas/genética , Ligação Proteica , Subunidades Proteicas/metabolismo , RNA Polimerase II/metabolismo , Proteínas de Ligação a RNA , Transcrição Gênica
12.
Cell Signal ; 27(10): 2045-53, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26215099

RESUMO

Increased rates of ribosome biogenesis and biomass accumulation are fundamental properties of rapidly growing and dividing malignant cells. The MYC oncoprotein drives growth predominantly via its ability to upregulate the ribosome biogenesis program, in particular stimulating the activity of the RNA Polymerase I (Pol I) machinery to increase ribosomal RNA (rRNA) transcription. Although MYC function is known to be highly dependent on the cellular signalling context, the pathways interacting with MYC to regulate transcription of ribosomal genes (rDNA) in vivo in response to growth factor status, nutrient availability and cellular stress are only beginning to be understood. To determine factors critical to MYC-dependent stimulation of rDNA transcription in vivo, we performed a transient expression screen for known oncogenic signalling pathways in Drosophila. Strikingly, from the broad range of pathways tested, we found that ribosomal protein S6 Kinase (S6K) activity, downstream of the TOR pathway, was the only factor rate-limiting for the rapid induction of rDNA transcription due to transiently increased MYC. Further, we demonstrated that one of the mechanism(s) by which MYC and S6K cooperate is through coordinate activation of the essential Pol I transcription initiation factor TIF-1A (RRN 3). As Pol I targeted therapy is now in phase 1 clinical trials in patients with haematological malignancies, including those driven by MYC, these data suggest that therapies dually targeting Pol I transcription and S6K activity may be effective in treating MYC-driven tumours.


Assuntos
DNA Ribossômico/genética , Drosophila melanogaster/genética , Proteínas Proto-Oncogênicas c-myc/fisiologia , Proteínas Quinases S6 Ribossômicas/fisiologia , Transcrição Gênica , Animais , Nucléolo Celular/enzimologia , Nucléolo Celular/ultraestrutura , Olho Composto de Artrópodes/enzimologia , Olho Composto de Artrópodes/ultraestrutura , DNA Ribossômico/metabolismo , Drosophila melanogaster/metabolismo , Proteínas Nucleares/metabolismo , Glândulas Salivares/enzimologia , Glândulas Salivares/ultraestrutura , Fatores de Transcrição/metabolismo
13.
Nat Commun ; 6: 7404, 2015 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-26074141

RESUMO

Nucleotide excision DNA repair (NER) pathway mutations cause neurodegenerative and progeroid disorders (xeroderma pigmentosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD)), which are inexplicably associated with (XP) or without (CS/TTD) cancer. Moreover, cancer progression occurs in certain patients, but not others, with similar C-terminal mutations in the XPB helicase subunit of transcription and NER factor TFIIH. Mechanisms driving overproliferation and, therefore, cancer associated with XPB mutations are currently unknown. Here using Drosophila models, we provide evidence that C-terminally truncated Hay/XPB alleles enhance overgrowth dependent on reduced abundance of RNA recognition motif protein Hfp/FIR, which transcriptionally represses the MYC oncogene homologue, dMYC. The data demonstrate that dMYC repression and dMYC-dependent overgrowth in the Hfp hypomorph is further impaired in the C-terminal Hay/XPB mutant background. Thus, we predict defective transcriptional repression of MYC by the Hfp orthologue, FIR, might provide one mechanism for cancer progression in XP/CS.


Assuntos
Proliferação de Células/genética , Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/genética , Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Transcrição/genética , Animais , Imunoprecipitação da Cromatina , DNA Helicases/genética , Drosophila melanogaster , Regulação da Expressão Gênica , Imuno-Histoquímica , Mutação , Transcrição Gênica , Xeroderma Pigmentoso/genética
14.
Cell Cycle ; 14(10): 1496-506, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25789785

RESUMO

The evolutionarily conserved neoplastic tumor suppressor protein, Lethal (2) giant larvae (Lgl), plays roles in cell polarity and tissue growth via regulation of the Hippo pathway. In our recent study, we showed that in the developing Drosophila eye epithelium, depletion of Lgl leads to increased ligand-dependent Notch signaling. lgl mutant tissue also exhibits an accumulation of early endosomes, recycling endosomes, early-multivesicular body markers and acidic vesicles. We showed that elevated Notch signaling in lgl(-) tissue can be rescued by feeding larvae the vesicle de-acidifying drug chloroquine, revealing that Lgl attenuates Notch signaling by limiting vesicle acidification. Strikingly, chloroquine also rescued the lgl(-) overgrowth phenotype, suggesting that the Hippo pathway defects were also rescued. In this extraview, we provide additional data on the regulation of Notch signaling and endocytosis by Lgl, and discuss possible mechanisms by which Lgl depletion contributes to signaling pathway defects and tumorigenesis.


Assuntos
Proteínas de Drosophila/metabolismo , Receptores Notch/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Animais , Autofagia/efeitos dos fármacos , Polaridade Celular , Cloroquina/farmacologia , Drosophila/metabolismo , Proteínas de Drosophila/genética , Endocitose , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Endossomos/metabolismo , Olho/metabolismo , Olho/patologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Microscopia Confocal , Mutação , Fenótipo , Proteína Quinase C/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Proteínas Supressoras de Tumor/genética , Proteínas rab de Ligação ao GTP/metabolismo , proteínas de unión al GTP Rab7
15.
Curr Biol ; 24(18): 2073-2084, 2014 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-25220057

RESUMO

BACKGROUND: The Drosophila melanogaster junctional neoplastic tumor suppressor, Lethal-2-giant larvae (Lgl), is a regulator of apicobasal cell polarity and tissue growth. We have previously shown in the developing Drosophila eye epithelium that, without affecting cell polarity, depletion of Lgl results in ectopic cell proliferation and blockage of developmental cell death due to deregulation of the Hippo signaling pathway. RESULTS: Here, we show that Notch signaling is increased in lgl-depleted eye tissue, independently of Lgl's function in apicobasal cell polarity. The upregulation of Notch signaling is ligand dependent and correlates with accumulation of cleaved Notch. Concomitant with higher cleaved Notch levels in lgl- tissue, early endosomes (Avalanche [Avl+]), recycling endosomes (Rab11+), early multivesicular bodies (Hrs+), and acidified vesicles, but not late endosomal markers (Car+ and Rab7+), accumulate. Colocalization studies revealed that Lgl associates with early to late endosomes and lysosomes. Upregulation of Notch signaling in lgl- tissue requires dynamin- and Rab5-mediated endocytosis and vesicle acidification but is independent of Hrs/Stam or Rab11 activity. Furthermore, Lgl regulates Notch signaling independently of the aPKC-Par6-Baz apical polarity complex. CONCLUSIONS: Altogether, our data show that Lgl regulates endocytosis to restrict vesicle acidification and prevent ectopic ligand-dependent Notch signaling. This Lgl function is independent of the aPKC-Par6-Baz polarity complex and uncovers a novel attenuation mechanism of ligand-activated Notch signaling during Drosophila eye development.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/fisiologia , Endocitose , Receptores Notch/genética , Transdução de Sinais , Proteínas Supressoras de Tumor/genética , Animais , Olho Composto de Artrópodes/crescimento & desenvolvimento , Olho Composto de Artrópodes/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Larva/genética , Larva/crescimento & desenvolvimento , Larva/fisiologia , Receptores Notch/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Regulação para Cima
16.
Cancers (Basel) ; 6(2): 879-96, 2014 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-24743776

RESUMO

In both Drosophila and mammalian systems, the Hippo (Hpo) signalling pathway controls tissue growth by inhibiting cell proliferation and promoting apoptosis. The core pathway consists of a protein kinase Hpo (MST1/2 in mammals) that is regulated by a number of upstream inputs including Drosophila Ras Association Factor, dRASSF. We have previously shown in the developing Drosophila eye epithelium that loss of the apico-basal cell polarity regulator lethal-(2)-giant-larvae (lgl), and the concomitant increase in aPKC activity, results in ectopic proliferation and suppression of developmental cell death by blocking Hpo pathway signalling. Here, we further explore how Lgl/aPKC interacts with the Hpo pathway. Deregulation of the Hpo pathway by Lgl depletion is associated with the mislocalization of Hpo and dRASSF. We demonstrate that Lgl/aPKC regulate the Hpo pathway independently of upstream inputs from Fat/Dachs and the Kibra/Expanded/Merlin complex. We show depletion of Lgl also results in accumulation and mislocalization of components of the dSTRIPAK complex, a major phosphatase complex that directly binds to dRASSF and represses Hpo activity. However, depleting dSTRIPAK components, or removal of dRASSF did not rescue the lgl-/- or aPKC overexpression phenotypes. Thus, Lgl/aPKC regulate Hpo activity by a novel mechanism, independently of dRASSF and dSTRIPAK. Surprisingly, removal of dRASSF in tissue with increased aPKC activity results in mild tissue overgrowth, indicating that in this context dRASSF acts as a tumor suppressor. This effect was independent of the Hpo and Ras Mitogen Activated Protein Kinase (MAPK) pathways, suggesting that dRASSF regulates a novel pathway to control tissue growth.

17.
J Clin Microbiol ; 52(3): 773-80, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24353004

RESUMO

A voluntary, cost-free external quality assessment (EQA) program established by the U.S. Centers for Disease Control and Prevention (CDC) was implemented to primarily monitor the performance of laboratories conducting HIV Early Infant Diagnosis (EID) from dried blood spots (DBS) in low- to middle-income countries since 2006. Ten blind DBS proficiency test (PT) specimens and 100 known HIV-positive and -negative DBS specimens (to be used as internal controls) were shipped triannually to participating laboratories with reports for the PT specimens due within 30 days. The participant's results and a summary of the performance of all participating laboratories and each diagnostic method were provided after each test cycle. Enrollment in the CDC PT program expanded progressively from 17 laboratories from 11 countries in 2006 to include 136 laboratories from 41 countries at the end of 2012. Despite external pressures to test and treat more children while expanding EID programs, mean PT test scores significantly improved over time as demonstrated by the upward trend from mid-2006 to the end of 2012 (P=0.001) and the increase in the percentage of laboratories scoring 100% (P=0.003). The mean test scores plateaued over the past 10 testing cycles, ranging between 98.2% and 99.7%, and discordant test results still occur but at a rate of no higher than 2.6%. Analysis of these test results suggests a positive impact of proficiency testing on the testing performance of the participating laboratories, and a continuous training program and proficiency testing participation may translate into laboratories improving their testing accuracy.


Assuntos
Técnicas de Laboratório Clínico/métodos , Técnicas de Laboratório Clínico/normas , Diagnóstico Precoce , Infecções por HIV/diagnóstico , HIV-1/isolamento & purificação , Ensaio de Proficiência Laboratorial , Sangue/virologia , Centers for Disease Control and Prevention, U.S. , Dessecação , Países em Desenvolvimento , Infecções por HIV/virologia , Pesquisa sobre Serviços de Saúde/tendências , Humanos , Lactente , Garantia da Qualidade dos Cuidados de Saúde/tendências , Manejo de Espécimes/métodos , Manejo de Espécimes/normas , Estados Unidos
18.
Arq. neuropsiquiatr ; 71(2): 110-112, Feb. 2013. tab
Artigo em Inglês | LILACS | ID: lil-663916

RESUMO

The olfactory bulb and tract (OB/OT) are among the earliest structures in the brain to undergo pathological changes in many neurodegenerative conditions. The availability of OB/OT samples from brain specimens in brain banks therefore assumes importance. We collected data from 5 years (2006-2010) regarding the presence or absence of OB/OT material in cases received by the Queen Square Brain Bank (QSBB) for Neurological Disorders, UCL Institute of Neurology, UK, to estimate availability of OB/OT material at the brain bank and also to look for possible associations. Of the 438 cases received, 320 had complete data regarding OB/OT and 29.4% of these had OB/OT in at least one half of the specimen. Unavailability of OB/OT was associated with larger post-mortem delays (p<0.001), suggesting that the delay might render the tissue more friable and hence lead to its loss. Brains from female donors also tended to have a higher availability in our samples.


O bulbo e o trato olfatórios (OB/OT) são algumas das estruturas cerebrais mais sensíveis a neurodegeneração. A disponibilidade deste material para estudos neuropatológicos em bancos de cérebro tem, portanto, grande relevância. Coletamos dados referentes a 5 anos (2006-2010) a respeito da presença ou ausência de OB/OT no Queen Square Brain Bank (QSBB) for Neurological Disorders, parte do UCL Institute of Neurology, Reino Unido, para estimar a disponibildade deste material em um banco de cérebro, e também para estudar fatores que influenciam essa disponibilidade. Dos 438 casos recebidos, encontramos dados referentes a presença ou ausência de OB/OT em 320, dos quais 29,4% possuiam OB/OT em pelo menos um lado. A indisponibilidade de OB/OT foi associada a maior intervalo entre a morte e a autópsia(p<0.001), sugerindo que o atraso pode deixar o material mais friável, levando aperda durante a coleta. Cérebros de doadoras femininas apresentaram maior disponibilidade de OB/OT em nossa amostra.


Assuntos
Feminino , Humanos , Masculino , Bulbo Olfatório , Bancos de Tecidos/estatística & dados numéricos , Autopsia , Fatores Sexuais , Fatores de Tempo , Reino Unido
19.
Neurology ; 80(4): 400-5, 2013 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-23303847

RESUMO

OBJECTIVES: Levetiracetam is a broad-spectrum antiepileptic drug (AED) which is currently licensed in the United States and the United Kingdom and Ireland for use as adjunctive treatment of focal-onset seizures and myoclonic seizures or generalized tonic-clonic seizures, occurring as part of generalized epilepsy syndromes. In the United Kingdom and Ireland, it is also licensed as monotherapy treatment for focal-onset seizures. Previous small studies have suggested a low risk for major congenital malformations (MCM) with levetiracetam use in pregnancy. METHODS: The UK and Ireland Epilepsy and Pregnancy Registers are prospective, observational registration and follow-up studies that were set up to determine the relative safety of all AEDs taken in pregnancy. Here we report our combined results for first-trimester exposures to levetiracetam from October 2000 to August 2011. RESULTS: Outcome data were available for 671 pregnancies. Of these, 304 had been exposed to levetiracetam in monotherapy, and 367 had been exposed to levetiracetam in combination with at least one other AED. There were 2 MCM in the monotherapy group (0.70%; 95% confidence interval [CI] 0.19%-2.51%) and 19 in the polytherapy group 5.56% (3.54%­8.56%) [corrected]. The MCM rate in the polytherapy group varied by AED regimen, with lower rates when levetiracetam was given with lamotrigine (1.77%; 95% CI 0.49%-6.22%) than when given with valproate (6.90%; 95% CI 1.91%-21.96%) or carbamazepine (9.38%; 95% CI 4.37%-18.98%). CONCLUSION: This study, in a meaningful number of exposed pregnancies, confirms a low risk for MCM with levetiracetam monotherapy use in pregnancy. MCM risk is higher when levetiracetam is taken as part of a polytherapy regimen, although further work is required to determine the risks of particular combinations. With respect to MCM, levetiracetam taken in monotherapy can be considered a safer alternative to valproate for women with epilepsy of childbearing age.


Assuntos
Anormalidades Induzidas por Medicamentos/epidemiologia , Epilepsia Generalizada/tratamento farmacológico , Epilepsia Tônico-Clônica/tratamento farmacológico , Piracetam/análogos & derivados , Complicações na Gravidez/induzido quimicamente , Adulto , Anticonvulsivantes/administração & dosagem , Anticonvulsivantes/efeitos adversos , Quimioterapia Combinada/efeitos adversos , Epilepsia Generalizada/epidemiologia , Epilepsia Tônico-Clônica/epidemiologia , Feminino , Seguimentos , Humanos , Recém-Nascido , Irlanda/epidemiologia , Levetiracetam , Masculino , Piracetam/administração & dosagem , Piracetam/efeitos adversos , Gravidez , Complicações na Gravidez/epidemiologia , Primeiro Trimestre da Gravidez/efeitos dos fármacos , Sistema de Registros/estatística & dados numéricos , Fatores de Risco , Reino Unido/epidemiologia , Ácido Valproico/administração & dosagem , Ácido Valproico/efeitos adversos
20.
Arq Neuropsiquiatr ; 71(2): 110-2, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23295368

RESUMO

The olfactory bulb and tract (OB/OT) are among the earliest structures in the brain to undergo pathological changes in many neurodegenerative conditions. The availability of OB/OT samples from brain specimens in brain banks therefore assumes importance. We collected data from 5 years (2006-2010) regarding the presence or absence of OB/OT material in cases received by the Queen Square Brain Bank (QSBB) for Neurological Disorders, UCL Institute of Neurology, UK, to estimate availability of OB/OT material at the brain bank and also to look for possible associations. Of the 438 cases received, 320 had complete data regarding OB/OT and 29.4% of these had OB/OT in at least one half of the specimen. Unavailability of OB/OT was associated with larger post-mortem delays (p<0.001), suggesting that the delay might render the tissue more friable and hence lead to its loss. Brains from female donors also tended to have a higher availability in our samples.


Assuntos
Bulbo Olfatório , Bancos de Tecidos/estatística & dados numéricos , Autopsia , Feminino , Humanos , Masculino , Fatores Sexuais , Fatores de Tempo , Reino Unido
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