Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
Support Care Cancer ; 30(2): 1521-1527, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34533630

RESUMO

PURPOSE: Prevention of chemotherapy-induced nausea and vomiting (CINV) is particularly challenging for patients receiving highly emetogenic preparative regimens before autologous stem cell transplantation (ASCT) due to the daily and continuous emetogenic stimulus of the multiple day chemotherapy. While studies have shown effective prevention of CINV during the conditioning phase with NK1 receptor antagonist (NK1RA)-containing regimens, there have been no studies evaluating antiemetic use during chemomobilization prior to ASCT. METHODS: This multicenter, open-label, phase IIa study evaluated the efficacy of every-other-day dosing of NEPA administered during chemomobilization in patients with relapsed-refractory aggressive non-Hodgkin's lymphoma. Eighty-one patients participated. RESULTS: Response rates were 77.8% for complete response (no emesis and no rescue use), 72.8% for complete control (complete response and no more than mild nausea), 86.4% for no emesis, and 82.7% for no rescue use during the overall phase (duration of chemomobilization through 48 h after). NEPA was well tolerated with no treatment-related adverse events reported. CONCLUSION: NEPA, administered with a simplified every-other-day schedule, show to be very effective in preventing CINV in patients at high risk of CINV undergoing to chemomobilization of hematopoietic stem cells prior to ASCT.


Assuntos
Antieméticos , Linfoma não Hodgkin , Náusea , Palonossetrom , Vômito , Antieméticos/efeitos adversos , Antineoplásicos/efeitos adversos , Quimioterapia Combinada/efeitos adversos , Transplante de Células-Tronco Hematopoéticas , Humanos , Linfoma não Hodgkin/tratamento farmacológico , Náusea/induzido quimicamente , Náusea/prevenção & controle , Palonossetrom/efeitos adversos , Transplante Autólogo , Resultado do Tratamento , Vômito/induzido quimicamente , Vômito/prevenção & controle
2.
Stem Cell Res ; 49: 102016, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33039807

RESUMO

GSX2 is a homeobox transcription factor (TF) controlling the specification of the ventral lateral ganglionic eminence and its major derivative, the corpus striatum. Medium spiny neurons (MSNs) represent the largest cell component of the striatum and they are primarily affected in Huntington disease (HD). Here, we used CRISPR technology to generate a pluripotent GSX2-reporter human embryonic stem cell (hESC) line that can be leveraged to monitor striatal differentiation in real-time and to enrich for MSN-committed progenitors.


Assuntos
Células-Tronco Embrionárias Humanas , Diferenciação Celular , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Corpo Estriado , Células-Tronco Embrionárias , Humanos , Neurônios
3.
Core Evid ; 15: 21-29, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32802009

RESUMO

INTRODUCTION: Antineoplastic drugs may induce several side effects, including chemotherapy-induced nausea and vomiting (CINV). Two neurotransmitters play a central role in mediating the emetic response: serotonin acting on the 5HT3 receptor and the substance P targeting the NK1 receptor. Indeed, a combination of a 5HT3 receptor antagonist (5HT3-RA) and a NK1 receptor antagonist (NK1-RA) together with dexamethasone has been shown to be very effective. In fact, this combination is actually widely used and recommended for CINV prophylaxis for highly emetogenic cisplatin-based adriamycin/cyclophosphamide (AC) and carboplatin-based regimens. NEPA (netupitant/palonosetron) is the only fixed combination antiemetic available and it is composed by the long-lasting second-generation 5HT3-RA palonosetron and the highly selective NK1-RA netupitant. AIM: The aims of this short review were to analyze the role of NEPA in CINV prophylaxis and management taking in account the risk factors related to the patient and to the antineoplastic treatment. EVIDENCE REVIEW: CINV development is not only correlated to the emetogenic potential of the antineoplastic drugs but is also very influenced by the patient characteristics and history, such as gender, age, alcohol intake, nausea during pregnancy and motion sickness. In pivotal and post-registration studies, NEPA has demonstrated to be effective and safe in both highly and moderately emetogenic chemotherapy. CONCLUSION: A proper assessment of both chemotherapy- and patient-related risk factors is paramount to properly evaluate an appropriate prophylaxis of CINV and NEPA by simplifying the therapy, guarantees fully adherence to antiemetic guidelines, and consequently improves the control of CINV, especially in high risk patients.

4.
Int J Hematol Oncol ; 9(1): IJH23, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32382409

RESUMO

We analyzed safety of NEPA (netupitant/palonosetron) and dexamethasone (NEPA+DEX) for the management of chemotherapy-induced nausea and vomiting (CINV) in classical Hodgkin's lymphoma patients that experienced CINV with a prophylaxis with palonosetron (PALO + DEX). In a retrospective, monocentric, noncomparative study, we analyzed adverse events and CINV grading in patients who switched from PALO + DEX to NEPA + DEX. Among 32 patients treated with ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) during the study period, 47% did not properly control CINV with PALO + DEX and were shifted to NEPA + DEX. Among these, 53.3% properly controlled CINV is for all the remaining chemotherapy cycles. We did not observe an increase of adverse events after switching to NEPA. In our study, NEPA did not show drug-drug interaction with ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) chemotherapy agents and NEPA administration was well tolerated with mild and transient adverse events.

5.
Bone Marrow Transplant ; 55(11): 2114-2120, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32346078

RESUMO

Despite the availability of several antiemetics, clinical findings show that control of chemotherapy-induced nausea and vomiting (CINV) continues to be a serious concern for hematological patients, mainly for those receiving multiple-day (MD) and high-dose (HD) chemotherapy (CT). For CINV prophylaxis, 5-hydroxytryptamine type-3 receptor antagonists (5HT3-RAs) and neurokinin 1 receptor antagonists (NK1-RAs) are usually administered together with dexamethasone, which may increase the risk of serious infections in patients undergoing myeloablative treatment. The rationale of this multicenter, open-label and phase IIa study was to explore the efficacy of multiple doses of NEPA (netupitant/palonosetron) given as an every-other-day regimen without dexamethasone in preventing CINV in patients with relapsed-refractory aggressive non-Hodgkin's lymphoma (R/R-NHL), eligible for autologous stem cell transplantation (ASCT) and treated with MD-HD-CT. Seventy patients participated to the study. According to the adopted Fleming one-stage design, the primary endpoint of this study was achieved. The CR values were 87.1% (primary endpoint, overall phase: days 1-8), 88.6% (acute phase: days 1-6), and 98.6% (delayed phase: days 7-8), while complete control (CR with no more than mild nausea) was 85.7% (overall phase), 88.6% (acute phase), and 95.7% (delayed phase). Moderate and severe episodes of nausea were reported by less than 10% of patients in the overall phase and less than 5% in both the acute and delayed phases. Regarding safety, NEPA was well tolerated with only one adverse event (constipation) evaluated as possibly related to NEPA administration. In conclusion, our study demonstrated that multiple alternate dosing of NEPA without the addition of dexamethasone is highly effective for preventing nausea and vomiting in this difficult setting, with a good tolerability profile.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Linfoma não Hodgkin , Dexametasona , Combinação de Medicamentos , Humanos , Isoquinolinas , Linfoma não Hodgkin/terapia , Náusea , Recidiva Local de Neoplasia , Piridinas , Quinuclidinas , Transplante Autólogo , Vômito
6.
ACS Med Chem Lett ; 11(2): 101-107, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32071674

RESUMO

Inhibitors of mutant isocitrate dehydrogenase (mIDH) 1 and 2 cancer-associated enzymes prevent the accumulation of the oncometabolite d-2-hydroxyglutarate (2-HG) and are under clinical investigation for the treatment of several cancers harboring an IDH mutation. Herein, we describe the discovery of vorasidenib (AG-881), a potent, oral, brain-penetrant dual inhibitor of both mIDH1 and mIDH2. X-ray cocrystal structures allowed us to characterize the compound binding site, leading to an understanding of the dual mutant inhibition. Furthermore, vorasidenib penetrates the brain of several preclinical species and inhibits 2-HG production in glioma tissue by >97% in an orthotopic glioma mouse model. Vorasidenib represents a novel dual mIDH1/2 inhibitor and is currently in clinical development for the treatment of low-grade mIDH glioma.

7.
BMC Cancer ; 19(1): 1268, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31888544

RESUMO

BACKGROUND: Nausea can be particularly prominent during the delayed period. Therefore, we performed a meta-analysis of the available randomised evidence to assess the average effect of palonosetron plus one-day dexamethasone (DEX; also called the DEX-sparing strategy) compared with palonosetron plus 3-day DEX for control of chemotherapy-induced nausea and vomiting (CINV), focusing on delayed nausea. METHODS: Eligible studies were identified through MEDLINE, Embase, and CENTRAL. Data on acute and delayed CINV were collected. Efficacy end points were complete response (CR; no vomiting, and no use of rescue medication), complete protection (CP; CR plus no clinically significant nausea), and total control (TC; CR plus no nausea) during the delayed period (days 2-5 after chemotherapy initiation). All randomised studies comparing palonosetron plus single-dose DEX (with or without another active agent) on day 1 followed by either no further DEX or additional DEX doses (both alone or in combination with another active agent) qualified. RESULTS: Of 864 citations screened, 8 studies with 1970 patients were included in the meta-analysis. During the delayed period, the combined odds ratio (OR) for all comparisons was 0.92 (95% confidence interval [CI], 0.76-1.12) for CR, 0.85 (95% CI, 0.71-1.03) for CP, and 0.92 (95% CI, 0.77-1.11) for TC in patients undergoing moderately emetogenic chemotherapy (MEC) or anthracycline and cyclophosphamide-containing chemotherapy (AC). The absolute risk difference (RD) computations for all end points in the delayed period did not exceed the threshold of - 4% (range, - 1% to - 4%). The effect was similar in subgroups defined by various study design parameters. The absolute RD computations in the acute period did not exceed the threshold of 1% (range, 0 to 1%). For one-day vs. 3-day DEX, numbers needed to be treated in order for one additional patient to not experience CR, CP and TC over the delayed period were 100, 25 and 50, respectively. CONCLUSIONS: This meta-analysis demonstrates that DEX-sparing regimens do not cause any significant loss in protection against not only vomiting but also nausea induced by single-day MEC or AC during the delayed period. These data should lead clinicians to optimise use of prophylactic DEX in clinical practice.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Dexametasona/uso terapêutico , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Náusea/prevenção & controle , Neoplasias/tratamento farmacológico , Vômito/prevenção & controle , Dexametasona/efeitos adversos , Humanos , Náusea/etiologia , Razão de Chances , Ensaios Clínicos Controlados Aleatórios como Assunto , Vômito/etiologia , Suspensão de Tratamento
8.
Blood ; 133(5): 436-445, 2019 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-30567753

RESUMO

Ibrutinib is a first-in-class inhibitor of Bruton tyrosine kinase (BTK) and has shown single-agent activity in recurrent/refractory central nervous system (CNS) lymphoma. Clinical responses are often transient or incomplete, suggesting a need for a combination therapy approach. We conducted a phase 1b clinical trial to explore the sequential combination of ibrutinib (560 or 840 mg daily dosing) with high-dose methotrexate (HD-MTX) and rituximab in patients with CNS lymphoma (CNSL). HD-MTX was given at 3.5 g/m2 every 2 weeks for a total of 8 doses (4 cycles; 1 cycle = 28 days). Ibrutinib was held on days of HD-MTX infusion and resumed 5 days after HD-MTX infusion or after HD-MTX clearance. Single-agent daily ibrutinib was administered continuously after completion of induction therapy until disease progression, intolerable toxicity, or death. We also explored next-generation sequencing of circulating tumor DNA (ctDNA) in cerebrospinal fluid (CSF) before and during treatment. The combination of ibrutinib, HD-MTX, and rituximab was tolerated with an acceptable safety profile (no grade 5 events, 3 grade 4 events). No dose-limiting toxicity was observed. Eleven of 15 patients proceeded to maintenance ibrutinib after completing 4 cycles of the ibrutinib/HD-MTX/rituximab combination. Clinical responses occurred in 12 of 15 patients (80%). Sustained tumor responses were associated with clearance of ctDNA from the CSF. This trial was registered at www.clinicaltrials.gov as #NCT02315326.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Linfoma/tratamento farmacológico , Metotrexato/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Rituximab/uso terapêutico , Adenina/análogos & derivados , Adulto , Tirosina Quinase da Agamaglobulinemia/antagonistas & inibidores , Idoso , Antineoplásicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Sistema Nervoso Central/genética , Neoplasias do Sistema Nervoso Central/patologia , DNA Tumoral Circulante/genética , Feminino , Humanos , Linfoma/genética , Linfoma/patologia , Metotrexato/efeitos adversos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia , Piperidinas , Inibidores de Proteínas Quinases/efeitos adversos , Pirazóis/efeitos adversos , Pirazóis/farmacocinética , Pirimidinas/efeitos adversos , Pirimidinas/farmacocinética , Rituximab/efeitos adversos , Resultado do Tratamento , Adulto Jovem
9.
Nat Commun ; 8(1): 2035, 2017 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-29229958

RESUMO

Transport of macromolecules through the nuclear pore by importins and exportins plays a critical role in the spatial regulation of protein activity. How cancer cells co-opt this process to promote tumorigenesis remains unclear. The epidermal growth factor receptor (EGFR) plays a critical role in normal development and in human cancer. Here we describe a mechanism of EGFR regulation through the importin ß family member RAN-binding protein 6 (RanBP6), a protein of hitherto unknown functions. We show that RanBP6 silencing impairs nuclear translocation of signal transducer and activator of transcription 3 (STAT3), reduces STAT3 binding to the EGFR promoter, results in transcriptional derepression of EGFR, and increased EGFR pathway output. Focal deletions of the RanBP6 locus on chromosome 9p were found in a subset of glioblastoma (GBM) and silencing of RanBP6 promoted glioma growth in vivo. Our results provide an example of EGFR deregulation in cancer through silencing of components of the nuclear import pathway.


Assuntos
Receptores ErbB/genética , Regulação Neoplásica da Expressão Gênica , Glioma/genética , beta Carioferinas/genética , Proteína ran de Ligação ao GTP/genética , Transporte Ativo do Núcleo Celular/genética , Animais , Antibióticos Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Células Cultivadas , Doxorrubicina/farmacologia , Receptores ErbB/metabolismo , Retroalimentação Fisiológica , Feminino , Técnicas de Silenciamento de Genes , Glioma/tratamento farmacológico , Glioma/metabolismo , Células HEK293 , Humanos , Camundongos Knockout , Camundongos SCID , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , beta Carioferinas/metabolismo , Proteína ran de Ligação ao GTP/metabolismo
10.
Trends Mol Med ; 23(9): 776-777, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28781061

RESUMO

Diffuse brain infiltration by tumor cells is a hallmark of glioma. Molecular mechanisms of brain invasion are poorly understood due to the difficulty to model this process in culture. A new study published in Cell Reports developed a three-dimensional organotypic model and identified interferon regulatory factor 3 (IRF3) as repressor of glioma invasion.


Assuntos
Neoplasias Encefálicas , Fator Regulador 3 de Interferon , Modelos Biológicos , Proteínas de Neoplasias , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Glioma , Humanos , Fator Regulador 3 de Interferon/genética , Fator Regulador 3 de Interferon/metabolismo , Invasividade Neoplásica , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo
11.
Cancer Discov ; 7(9): 1018-1029, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28619981

RESUMO

Bruton tyrosine kinase (BTK) links the B-cell antigen receptor (BCR) and Toll-like receptors with NF-κB. The role of BTK in primary central nervous system (CNS) lymphoma (PCNSL) is unknown. We performed a phase I clinical trial with ibrutinib, the first-in-class BTK inhibitor, for patients with relapsed or refractory CNS lymphoma. Clinical responses to ibrutinib occurred in 10 of 13 (77%) patients with PCNSL, including five complete responses. The only PCNSL with complete ibrutinib resistance harbored a mutation within the coiled-coil domain of CARD11, a known ibrutinib resistance mechanism. Incomplete tumor responses were associated with mutations in the B-cell antigen receptor-associated protein CD79B. CD79B-mutant PCNSLs showed enrichment of mammalian target of rapamycin (mTOR)-related gene sets and increased staining with PI3K/mTOR activation markers. Inhibition of the PI3K isoforms p110α/p110δ or mTOR synergized with ibrutinib to induce cell death in CD79B-mutant PCNSL cells.Significance: Ibrutinib has substantial activity in patients with relapsed or refractory B-cell lymphoma of the CNS. Response rates in PCNSL were considerably higher than reported for diffuse large B-cell lymphoma outside the CNS, suggesting a divergent molecular pathogenesis. Combined inhibition of BTK and PI3K/mTOR may augment the ibrutinib response in CD79B-mutant human PCNSLs. Cancer Discov; 7(9); 1018-29. ©2017 AACR.See related commentary by Lakshmanan and Byrd, p. 940This article is highlighted in the In This Issue feature, p. 920.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Linfoma de Células B/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Adenina/análogos & derivados , Adulto , Tirosina Quinase da Agamaglobulinemia , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacocinética , Proteínas Adaptadoras de Sinalização CARD/genética , Neoplasias do Sistema Nervoso Central/sangue , Neoplasias do Sistema Nervoso Central/líquido cefalorraquidiano , Neoplasias do Sistema Nervoso Central/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Guanilato Ciclase/genética , Humanos , Linfoma de Células B/sangue , Linfoma de Células B/líquido cefalorraquidiano , Linfoma de Células B/metabolismo , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Mutação , Piperidinas , Inibidores de Proteínas Quinases/efeitos adversos , Inibidores de Proteínas Quinases/farmacocinética , Proteínas Tirosina Quinases/antagonistas & inibidores , Pirazóis/efeitos adversos , Pirazóis/farmacocinética , Pirimidinas/efeitos adversos , Pirimidinas/farmacocinética , Resultado do Tratamento , Adulto Jovem
12.
Wiley Interdiscip Rev Dev Biol ; 5(6): 640-658, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27647730

RESUMO

Neural stem cells (NSCs) reside in specialized niches in the adult mammalian brain. The ventricular-subventricular zone (V-SVZ), adjacent to the lateral ventricles, gives rise to olfactory bulb (OB) neurons, and some astrocytes and oligodendrocytes throughout life. In vitro assays have been widely used to retrospectively identify NSCs. However, cells that behave as stem cells in vitro do not reflect the identity, diversity, and behavior of NSCs in vivo. Novel tools including fluorescence activated cell sorting, lineage-tracing, and clonal analysis have uncovered multiple layers of adult V-SVZ NSC heterogeneity, including proliferation state and regional identity. In light of these findings, we reexamine the concept of adult NSCs, considering heterogeneity as a key parameter for analyzing their dynamics in vivo. V-SVZ NSCs form a mosaic of quiescent (qNSCs) and activated cells (aNSCs) that reside in regionally distinct microdomains, reflecting their regional embryonic origins, and give rise to specific subtypes of OB interneurons. Prospective purification and transcriptome analysis of qNSCs and aNSCs has illuminated their molecular and functional properties. qNSCs are slowly dividing, have slow kinetics of neurogenesis in vivo, can be recruited to regenerate the V-SVZ, and only rarely give rise to in vitro colonies. aNSCs are highly proliferative, undergo rapid clonal expansion of the neurogenic lineage in vivo, and readily form in vitro colonies. Key open questions remain about stem cell dynamics in vivo and the lineage relationship between qNSCs and aNSCs under homeostasis and regeneration, as well as context-dependent plasticity of regionally distinct adult NSCs under different external stimuli. WIREs Dev Biol 2016, 5:640-658. doi: 10.1002/wdev.248 For further resources related to this article, please visit the WIREs website.


Assuntos
Células-Tronco Adultas/metabolismo , Células-Tronco Neurais/metabolismo , Neurogênese/fisiologia , Nicho de Células-Tronco/fisiologia , Adulto , Células-Tronco Adultas/citologia , Diferenciação Celular , Humanos , Células-Tronco Neurais/citologia
13.
Cell Stem Cell ; 19(5): 643-652, 2016 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-27452173

RESUMO

Specialized niches support the lifelong maintenance and function of tissue-specific stem cells. Adult neural stem cells in the ventricular-subventricular zone (V-SVZ) contact the cerebrospinal fluid (CSF), which flows through the lateral ventricles. A largely ignored component of the V-SVZ stem cell niche is the lateral ventricle choroid plexus (LVCP), a primary producer of CSF. Here we show that the LVCP, in addition to performing important homeostatic support functions, secretes factors that promote colony formation and proliferation of purified quiescent and activated V-SVZ stem cells and transit-amplifying cells. The functional effect of the LVCP secretome changes throughout the lifespan, with activated neural stem cells being especially sensitive to age-related changes. Transcriptome analysis identified multiple factors that recruit colony formation and highlights novel facets of LVCP function. Thus, the LVCP is a key niche compartment that translates physiological changes into molecular signals directly affecting neural stem cell behavior.


Assuntos
Células-Tronco Adultas/citologia , Envelhecimento/fisiologia , Plexo Corióideo/citologia , Células-Tronco Neurais/citologia , Transdução de Sinais , Nicho de Células-Tronco , Células-Tronco Adultas/metabolismo , Animais , Proliferação de Células , Plexo Corióideo/metabolismo , Células Clonais , Perfilação da Expressão Gênica , Ventrículos Laterais/citologia , Camundongos , Células-Tronco Neurais/metabolismo
14.
Neuron ; 82(3): 545-59, 2014 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-24811379

RESUMO

Adult neurogenic niches harbor quiescent neural stem cells; however, their in vivo identity has been elusive. Here, we prospectively isolate GFAP(+)CD133(+) (quiescent neural stem cells [qNSCs]) and GFAP(+)CD133(+)EGFR(+) (activated neural stem cells [aNSCs]) from the adult ventricular-subventricular zone. aNSCs are rapidly cycling, highly neurogenic in vivo, and enriched in colony-forming cells in vitro. In contrast, qNSCs are largely dormant in vivo, generate olfactory bulb interneurons with slower kinetics, and only rarely form colonies in vitro. Moreover, qNSCs are Nestin negative, a marker widely used for neural stem cells. Upon activation, qNSCs upregulate Nestin and EGFR and become highly proliferative. Notably, qNSCs and aNSCs can interconvert in vitro. Transcriptome analysis reveals that qNSCs share features with quiescent stem cells from other organs. Finally, small-molecule screening identified the GPCR ligands, S1P and PGD2, as factors that actively maintain the quiescent state of qNSCs.


Assuntos
Células-Tronco Adultas/fisiologia , Ventrículos Laterais/citologia , Ventrículos Laterais/fisiologia , Células-Tronco Neurais/fisiologia , Animais , Astrócitos/fisiologia , Biomarcadores/metabolismo , Separação Celular/métodos , Células Cultivadas , Humanos , Camundongos , Camundongos Transgênicos , Estudos Prospectivos , Transcriptoma/genética
15.
J Physiol ; 587(Pt 11): 2457-72, 2009 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-19332500

RESUMO

Light adaptation in vertebrate photoreceptors is mediated by multiple mechanisms, one of which could involve nuclear feedback and changes in gene expression. Therefore, we have investigated light adaptation-associated changes in gene expression using microarrays and real-time PCR in isolated photoreceptors, in cultured isolated retinas and in acutely isolated retinas. In all three preparations after 2 h of an exposure to a bright light, we observed an up-regulation of almost 100% of three genes, Sag, Guca1a and Guca1b, coding for proteins known to play a major role in phototransduction: arrestin, GCAP1 and GCAP2. No detectable up-regulation occurred for light exposures of less than 1 h. Functional in vivo electroretinographic tests show that a partial recovery of the dark current occurred 1-2 h after prolonged illumination with a steady light that initially caused a substantial suppression of the photoresponse. These observations demonstrate that prolonged illumination results in the up-regulation of genes coding for proteins involved in the phototransduction signalling cascade, possibly underlying a novel component of light adaptation occurring 1-2 h after the onset of a steady bright light.


Assuntos
Adaptação Ocular , Arrestina/metabolismo , Proteínas Ativadoras de Guanilato Ciclase/metabolismo , Luz , Células Fotorreceptoras de Vertebrados/metabolismo , Visão Ocular , Adaptação Ocular/genética , Animais , Arrestina/genética , Células Cultivadas , Adaptação à Escuridão , Eletrorretinografia , Perfilação da Expressão Gênica/métodos , Proteínas Ativadoras de Guanilato Ciclase/genética , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Análise de Sequência com Séries de Oligonucleotídeos , Estimulação Luminosa , RNA Mensageiro/metabolismo , Ratos , Ratos Long-Evans , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Regulação para Cima , Visão Ocular/genética
16.
Biophys J ; 90(10): 3599-607, 2006 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-16513780

RESUMO

With the aim of understanding the relation between structure and gating of CNGA1 channels from bovine rod, an extensive cysteine scanning mutagenesis was performed. Each residue from Phe-375 to Val-424 was mutated into a cysteine one at a time and the modification caused by various sulfhydryl reagents was analyzed. The addition of the mild oxidizing agent copper phenanthroline (CuP) in the open (presence of 1 mM cGMP) or closed state locked the channel in the respective states. A subsequent treatment with the reducing agent DTT restored normal gating fully in the open state and partially in the closed state. This action of CuP was not observed when F380 was mutated into a cysteine in the cysteine-free CNGA1 channel and in the double mutant C314S&F380C. These observations suggest that these effects are mediated by the formation of a disulfide bond (S-S) between F380C and the endogenous Cys-314 in the S5 segment. It can be rationalized by supposing that during gating the S6 segment rotates anticlockwise-when viewed from the extracellular side-by approximately 30 degrees .


Assuntos
Ativação do Canal Iônico/fisiologia , Canais Iônicos/química , Canais Iônicos/metabolismo , Oócitos/fisiologia , Animais , Bovinos , Células Cultivadas , Canais de Cátion Regulados por Nucleotídeos Cíclicos , Cisteína/química , Cisteína/genética , Cisteína/metabolismo , Canais Iônicos/genética , Mutagênese Sítio-Dirigida , Conformação Proteica , Relação Estrutura-Atividade , Xenopus laevis
17.
FEBS Lett ; 579(9): 1968-72, 2005 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-15792804

RESUMO

Cyclic nucleotide-gated (CNG) ion channels, underlying sensory transduction in vertebrate photoreceptors and olfactory sensory neurons, require cyclic nucleotides to open. Here, we present structural models of the tetrameric CNG channel pore from bovine rod in both open and closed states, as obtained by combining homology modeling-based techniques, experimentally derived spatial constraints and structural patterns present in the PDB database. Gating is initiated by an anticlockwise rotation of the N-terminal region of the C-linker, which is then, transmitted through the S6 transmembrane helices to the P-helix, and in turn from this to the pore lumen, which opens up from 2 to 5A thus allowing for ion permeation. The approach, here presented, is expected to provide a general methodology for model ion channels and their gating when structural templates are available and an extensive electrophysiological analysis has been performed.


Assuntos
Ativação do Canal Iônico , Canais Iônicos/química , Sequência de Aminoácidos , Animais , Bovinos , Canais de Cátion Regulados por Nucleotídeos Cíclicos , Canais Iônicos/metabolismo , Camundongos , Modelos Estruturais , Dados de Sequência Molecular , Estrutura Molecular , Nucleotídeos Cíclicos/metabolismo , Conformação Proteica , Alinhamento de Sequência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...