RESUMO
Maintaining neurogenesis in growing tissues requires a tight balance between progenitor cell proliferation and differentiation. In the zebrafish retina, neuronal differentiation proceeds in two stages with embryonic retinal progenitor cells (RPCs) of the central retina accounting for the first rounds of differentiation, and stem cells from the ciliary marginal zone (CMZ) being responsible for late neurogenesis and growth of the eye. In this study, we analyse two mutants with small eyes that display defects during both early and late phases of retinal neurogenesis. These mutants carry lesions in gdf6a, a gene encoding a BMP family member previously implicated in dorsoventral patterning of the eye. We show that gdf6a mutant eyes exhibit expanded retinoic acid (RA) signalling and demonstrate that exogenous activation of this pathway in wild-type eyes inhibits retinal growth, generating small eyes with a reduced CMZ and fewer proliferating progenitors, similar to gdf6a mutants. We provide evidence that RA regulates the timing of RPC differentiation by promoting cell cycle exit. Furthermore, reducing RA signalling in gdf6a mutants re-establishes appropriate timing of embryonic retinal neurogenesis and restores putative stem and progenitor cell populations in the CMZ. Together, our results support a model in which dorsally expressed gdf6a limits RA pathway activity to control the transition from proliferation to differentiation in the growing eye.
Assuntos
Fator 6 de Diferenciação de Crescimento/genética , Neurogênese/genética , Retina/embriologia , Tretinoína/metabolismo , Proteínas de Peixe-Zebra/genética , Peixe-Zebra/embriologia , Animais , Proteínas Morfogenéticas Ósseas/metabolismo , Ciclo Celular/genética , Proliferação de Células , Embrião não Mamífero/embriologia , Neurogênese/fisiologia , Transdução de Sinais/genética , Células-Tronco/citologiaRESUMO
BACKGROUND: Designing clinical trials with the emphasis on the patient-centered approach and focusing on clinical outcomes that are meaningful to patients is viewed as a priority by drug developers, regulatory agencies, payers, clinicians, and patients. This study aimed to capture information on clinical trial endpoints that would be most important and relevant for patients with advanced breast cancer, based on patient-reported outcomes. METHODS: Patients with either advanced triple-negative breast cancer [TNBC] and a maximum of two lines of systemic therapy or hormone receptor-positive/human epidermal growth factor receptor 2-negative [HR+/HER2-] breast cancer and a maximum of three lines of systemic therapy, participated in semi-structured concept elicitation interviews. Concept saturation was assessed. A sign, symptom, or impact was defined as "salient" if mentioned by ≥ 60% of participants, with an average bother rating of ≥ 5 (0-10 Scale). Participants were also asked about treatment priorities and to evaluate hypothetical scenarios showing different health-related functioning and quality-of-life treatment outcomes, using graphical representations. RESULTS: Thirty-two participants (97% women; aged 29+ years) with TNBC (n = 17) or HR+/HER2- breast cancer (n = 15) provided generally similar reports on symptom experience, with fatigue and pain being most salient, though importance of certain treatment-related symptoms varied between the two groups. Patients reported consistent perspectives on the importance of treatment outcomes: when considering a new treatment, they prioritized efficacy of the therapy, acceptable tolerability, stability, predictability of symptoms over time, and the duration of preserved health-related quality of life and physical functioning. The meaningful difference in preserved physical functioning was 2-3 months for 46% of participants with TNBC, whereas for most participants with HR+/HER2- breast cancer it started from 6-7 months. Both groups of participants found it easier to accept some toxicity at the beginning of therapy if it was followed by improvement, as opposed to improvement followed by deterioration. CONCLUSION: The results may help to inform the design of patient-centered clinical trials, to interpret health-related quality of life and/or patient-reported outcomes, and to optimize care for patients with advanced breast cancer.
Assuntos
Neoplasias da Mama , Neoplasias de Mama Triplo Negativas , Feminino , Humanos , Masculino , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Medidas de Resultados Relatados pelo Paciente , Qualidade de Vida , Receptor ErbB-2/metabolismo , Resultado do Tratamento , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , AdultoRESUMO
Background: An understanding of the experience of patients with progressive fibrosing interstitial lung disease (PF-ILD) is needed to select appropriate patient-reported outcome measures (PROMs) to evaluate treatment effect in clinical trials. Methods: A systematic literature review was conducted to develop a preliminary conceptual model of the symptoms experienced by patients with PF-ILD and the impacts the disease has on them. An online survey and consensus meetings were then conducted with 12-14 stakeholders (patients, clinicians, regulatory and payer advisors) to refine the conceptual model and critically appraise how key concepts should be measured by PROMs. PROMs assessed included Living with Idiopathic Pulmonary Fibrosis, Living with Pulmonary Fibrosis, the King's Brief Interstitial Lung Disease questionnaire, Cough and Sputum Assessment Questionnaire, Evaluating Respiratory Symptoms, Leicester Cough Questionnaire, Functional Assessment of Chronic Illness Therapy (Dyspnoea/Fatigue) and St George's Respiratory Questionnaire for Idiopathic Pulmonary Fibrosis. Results: The literature review identified 36 signs/symptoms and 43 impacts directly or indirectly related to pulmonary aspects of PF-ILD. The most relevant symptoms identified by participants included shortness of breath on exertion, fatigue and cough; relevant impacts included effects on physical functioning, activities of daily living and emotional wellbeing. These are presented in a conceptual model. Consensus opinion was that existing PROMs need further modification and validation before use in clinical trials. Conclusions: The conceptual model improves understanding of the symptoms and impacts that living with PF-ILD has on patients' wellbeing. It can help to inform the choice of PROMs in clinical trials and highlight aspects to assess in the clinical care of patients with PF-ILD.
RESUMO
How action potentials regulate myelination by oligodendrocytes is uncertain. We show that neuronal activity raises [Ca2+]i in developing oligodendrocytes in vivo and that myelin sheath elongation is promoted by a high frequency of [Ca2+]i transients and prevented by [Ca2+]i buffering. Sheath elongation occurs ~1 h after [Ca2+]i elevation. Sheath shortening is associated with a low frequency of [Ca2+]i transients but with longer duration [Ca2+]i bursts. Thus, [Ca2+]i controls myelin sheath development.
Assuntos
Axônios/fisiologia , Cálcio/metabolismo , Bainha de Mielina/fisiologia , Neurônios/fisiologia , Oligodendroglia/fisiologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/genética , Animais , Animais Geneticamente Modificados , Axônios/efeitos dos fármacos , Cálcio/farmacologia , Quelantes/farmacologia , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Mivacúrio/farmacologia , Proteína Básica da Mielina/genética , Proteína Básica da Mielina/metabolismo , Fármacos Neuromusculares não Despolarizantes/farmacologia , Neurônios/efeitos dos fármacos , Fatores de Transcrição SOXE/genética , Fatores de Transcrição SOXE/metabolismo , Bloqueadores dos Canais de Sódio/farmacologia , Medula Espinal/citologia , Tetrodotoxina/farmacologia , Peixe-Zebra , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
The role of NMDA receptors in oligodendrocytes has been controversial. A new paper (Saab et al., 2016) suggests they play a key role in regulating glucose uptake in response to axonal glutamate release, thus controlling metabolic cooperation between oligodendrocytes and axons.