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Objective: ACTH-producing pancreatic NETs have a propensity to metastasize, and in patients with metastases, there is no established method yet to precisely determine if the excess ACTH is produced by the primary or the metastatic tumors. Localizing the source of production of ACTH in such cases is important for devising suitable treatment strategies and evaluating the benefit of local therapies from the viewpoint of control of Cushing's syndrome. Methods: We performed the selective arterial calcium injection (SACI) test combined with selective portal and hepatic venous sampling in a 32-year-old female patient with ectopic ACTH-producing pancreatic NET and liver metastases. Results: The blood level of ACTH after Ca loading was significantly elevated only in the vessels thought to be directly feeding the pancreatic tumor, and Ca loading from any artery did not significantly increase ACTH concentrations in the hepatic veins compared to the main trunk of the portal vein. Conclusions: The present case demonstrates that there might be an ACTH-producing p-NET that responds to Ca loading. Further in vitro studies are required to validate this possibility.
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Background/Aim: The number of older patients with breast cancer has been increasing and a major challenge is to develop optimal treatment strategies for these patients, who often have comorbidities. Obesity is reportedly a poor prognostic factor in breast cancer, however there is limited research on underweight patients. Clarifying the relationship between physique and prognosis may contribute to the establishment of optimal treatment strategies for older patients with breast cancer. Patients and Methods: This retrospective study examined clinicopathological data from a multicenter collaborative database on 1,076 patients aged 70 years or older who had undergone curative surgery. According to the body mass index (BMI), patient physique was defined as underweight (<18.5 kg/m2), normal (18.5-24.9 kg/m2) or obese (≥25 kg/m2). In this study, we explored the relationship between the physique of patients with breast cancer and outcomes. Results: Underweight patients had a significantly lower rate of chemotherapy administration (p=0.017) and a higher rate of presence of other cancer (p=0.022). During the observation period (median of 75.2 months), 133 patients (12%) developed recurrent disease and 131 patients (12%) died. Age, BMI, tumor size, progesterone receptor and the presence of other cancer were independent factors relating to overall survival (p<0.001, p=0.027, p=0.002, p=0.008 and p=0.005, respectively). Patients with a low BMI had a significantly shorter overall survival, but there was no association with disease-free survival in this subset of patients. Conclusion: Overall survival was shorter in underweight older patients with breast cancer. Our data indicate that being underweight should be considered both in treatment decisions and in future studies of outcomes for older patients with breast cancer.
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BACKGROUND: Cat scratch disease (CSD) is an infectious disease caused by Bartonella henselae. CSD follows a typical course, characterized by regional lymphadenopathy. In atypical CSD, the lesions spread to systemic organs and can cause fever of unknown origin (FUO). A previous study showed the usefulness of whole-body magnetic resonance imaging (WB-MRI) with diffusion-weighted imaging (DWI) for limited areas in the diagnosis of FUO, but there are no studies on the clinical utility of whole-body DWI (WB-DWI). We herein report the case of an immunocompetent young man in whom contrast-enhanced CT-unidentifiable multiple liver abscess and osteomyelitis were successfully detected by WB-DWI. Follow-up with a liver biopsy helped confirm an atypical CSD diagnosis. CASE PRESENTATION: A 23-year-old previously healthy man was admitted for a 19-day history of high fever despite 3-day treatment by azithromycin. His physical examination was unremarkable and contrast-enhanced CT showed only a low attenuated area in the right lobe of the liver, indicating a cyst. WB-DWI revealed multiple nodular lesions of hypo-diffusion in the liver, spine, and pelvic region. The biopsy specimens of the liver abscess showed no evidence of tuberculosis/malignancy and the polymerase chain reaction (PCR) test of liver abscess aspirate showed positive findings for Bartonellahenselae, confirming the diagnosis of CSD. He completed minocycline monotherapy for a total of 60 days without any deterioration. CONCLUSIONS: WB-DWI can be useful for the diagnosis of atypical CSD with hepatic and bone involvement, which can cause FUO in young immunocompetent adults.
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Bartonella henselae , Doença da Arranhadura de Gato , Febre de Causa Desconhecida , Abscesso Hepático , Doença da Arranhadura de Gato/diagnóstico por imagem , Doença da Arranhadura de Gato/tratamento farmacológico , Humanos , Imageamento por Ressonância Magnética , Masculino , Imagem Corporal TotalRESUMO
BACKGROUND: Due to the lack of clinical trials on the efficacy of chemotherapy in older patients, an optimal treatment strategy has not been developed. We investigated whether adjuvant chemotherapy could improve the survival of older patients with breast cancer in Japan. METHODS: We retrospectively analyzed data of patients with breast cancer aged ≥ 70 years who underwent breast cancer surgery in eight hospitals between 2008 and 2013. Clinical treatment and follow-up data were obtained from the patients' medical electric records. RESULTS: A total of 1095 patients were enrolled, of which 905 were included in the initial non-matched analysis. The median age and follow-up period were 75 (range 70-93) and 6.3 years, respectively. Of these patients, 127 (14%) received adjuvant chemotherapy (Chemo group) while the remaining 778 (86%) did not (Control group). The Chemo group was younger (mean age in years 73 vs 76; P < 0.0001), had a larger pathological tumor size (mean mm 25.9 vs 19.9; P < 0.0001), and more metastatic axillary lymph nodes (mean numbers 2.7 vs 0.7; P < 0.0001) than the Control group. The disease-free survival (DFS) and overall survival (OS) did not differ significantly between the two groups (P = 0.783 and P = 0.558). After matched analyses, DFS was found to be significantly prolonged with adjuvant chemotherapy (P = 0.037); however, OS difference in the matched cohort was not statistically significant (P = 0.333). CONCLUSION: The results showed that adjuvant chemotherapy was associated with a reduced risk of recurrence, but survival benefits were limited.
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Neoplasias da Mama , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Quimioterapia Adjuvante , Intervalo Livre de Doença , Feminino , Humanos , Mastectomia , Estudos RetrospectivosRESUMO
BACKGROUND: The efficacy of anti-programmed death receptor 1 (PD-1) therapy in patients with large cell neuroendocrine carcinoma (LCNEC) remains unclear. We investigated the outcome of anti-PD-1 therapy and its predictive markers by evaluating the immune-related tumor microenvironment. PATIENTS: We retrospectively reviewed patients with advanced LCNEC treated with systemic chemotherapy. We also evaluated PD ligand 1 (PD-L1) expression (clone: 22C3), CD8-positive tumor-infiltrating lymphocytes (TILs), and the mutational profiles. RESULTS: Seventy patients were enrolled, and 13 of 70 patients received anti-PD-1 therapy. The progression-free survival (PFS) and objective response rate (ORR) of the anti-PD-1 therapy were 4.2 months and 39%, respectively. The overall survival of patients treated with anti-PD-1 therapy (n = 13) was significantly better than those treated without anti-PD-1 therapy (n = 57) (25.2 months vs 10.9 months; P = .02). Among the 13 patients treated with anti-PD-1 therapy, 10 patients (90%) had PD-L1-negative tumors. Patients with a high density of tumoral CD8-positive TILs (≥38/mm2) had a significantly better ORR and PFS than those with a low density of tumoral CD8-positive TILs (ORR: P = .02; PFS: P = .003). Additionally, all 3 patients with TP53 mutation co-occurring with PIK3CA mutation (2 of 8 patients) or RB1 mutation (1 of 8 patients) responded to anti-PD-1 therapy. CONCLUSIONS: Anti-PD-1 therapy was effective regardless of PD-L1 positivity in patients with advanced LCNEC. Our investigation might suggest that the density of tumoral CD8-positive TILs and the presence of co-occurring mutations are predictors of the efficacy of anti-PD-1 therapy in patients with advanced LCNEC.
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Antineoplásicos Imunológicos/administração & dosagem , Carcinoma de Células Grandes/tratamento farmacológico , Carcinoma Neuroendócrino/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígeno B7-H1/antagonistas & inibidores , Carcinoma de Células Grandes/genética , Carcinoma de Células Grandes/imunologia , Carcinoma Neuroendócrino/genética , Carcinoma Neuroendócrino/imunologia , Feminino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/imunologia , Masculino , Pessoa de Meia-Idade , Mutação , Intervalo Livre de Progressão , Estudos Retrospectivos , Taxa de Sobrevida , Microambiente Tumoral/imunologiaRESUMO
Background: The relationship between left ventricular diastolic dysfunction (LVDD) and paroxysmal atrial fibrillation (PAF) remains unclear because of a lack of standard measures to evaluate LVDD. Accordingly, we examined the association between the prevalence of PAF and each LVDD grade determined according to the latest American Society of Echocardiography guidelines. MethodsâandâResults: In all, 2,063 patients without persistent AF who underwent echocardiography at Saitama Municipal Hospital from July 2016 to June 2017 were included in the study. Patients were divided into LVDD 6 categories: No-LVDD (n=1,107), Borderline (n=392), Grade 1 (n=204), Indeterminate (n=62), Grade 2 (n=254), and Grade 3 (n=44). PAF was documented in 111 (10.0%), 81 (20.7%), 28 (13.7%), 6 (9.7%), 52 (20.5%), and 24 (54.5%) patients in the No-LVDD, Borderline, Grade 1, Indeterminate, Grade 2, and Grade 3 categories, respectively. PAF prevalence was higher in patients with Grade 3 LVDD across the whole study population. Subgroup analyses showed that the prevalence of PAF increased with increased LVDD grade in patients with reduced left ventricular ejection fraction. This relationship was significant in multivariate analysis including various patient characteristics. Conclusions: LVDD severity determined on the basis of the latest echocardiographic criteria was associated with the prevalence of PAF. The present findings shed light on the development of new therapeutic markers for PAF.
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Dramatic progress in targeted therapy and immunotherapy has been changing clinical practices in lung cancer. With the accumulation of clinical practice, it has become clear that pre-existing interstitial pneumonia (IP) could be a risk factor for drug-induced lung injury, which has enhanced awareness regarding the difficulty in treating lung cancer with comorbid IP. Unfortunately, there is only low-grade evidence in the field of lung cancer with comorbid IP, because almost all clinical trials exclude such patients. There have been very few specialized clinical trials for patients with lung cancer and underlying IPs thus far. Therefore, it is necessary to treat such cases empirically or to give up on the treatment itself. Considering these circumstances, establishing how to treat lung cancer with comorbid IP is an urgent issue. This paper is a summary of the official statement reported by the Diffuse Lung Disease/Thoracic Oncology Assembly and the Japanese Respiratory Society (JRS) in 2017, which attempts to approach lung cancer with comorbid IP systematically.
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Doenças Pulmonares Intersticiais/terapia , Neoplasias Pulmonares/terapia , Pneumologia/organização & administração , Humanos , Japão/epidemiologia , Doenças Pulmonares Intersticiais/epidemiologia , Neoplasias Pulmonares/epidemiologiaRESUMO
BACKGROUND: Cytotoxic chemotherapy for advanced non-small cell lung cancer (NSCLC) as second-line or subsequent treatment generally results in a poor treatment outcome. Several reports have indicated that subsequent cytotoxic chemotherapy in patients who have received immune checkpoint inhibitors (ICIs) might have relatively better efficacy. METHODS: The clinical data of advanced NSCLC patients treated with nivolumab during clinical practice at the National Cancer Center Hospital between 17 December 2015 and 31 August 2017 were consecutively reviewed, and the treatment outcomes of docetaxel-based chemotherapy (docetaxel +/- ramucirumab) or S-1 after nivolumab were analyzed. The results were then compared with those of advanced NSCLC patients treated with docetaxel or S-1 but not ICIs during clinical practice between 17 December 2014 and 16 December 2015. RESULTS: Thirty patients were administered docetaxel-based chemotherapy and 21 patients were administered S-1 in any line after nivolumab. Twenty-four patients were administered docetaxel-based chemotherapy and 15 patients were administered S-1 immediately after nivolumab. Sixty-six patients were administered docetaxel and 23 patients were administered S-1 without ICIs. The objective response rate, disease control rate, and median progression-free survival duration were 28.6%, 53.6%, and 5.26 months for patients receiving docetaxel-based chemotherapy or S-1 immediately after nivolumab treatment; 24.3%, 51.4%, and 3.88 months for patients receiving docetaxel-based chemotherapy or S-1 in any line after nivolumab; and 16.4%, 56.7%, and 2.74 months, for patients receiving docetaxel or S-1 without ICIs, respectively. CONCLUSION: Subsequent cytotoxic chemotherapy, especially immediately after nivolumab, has better treatment efficacy than that of regimens without ICI pretreatment.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Adulto , Idoso , Anticorpos Monoclonais Humanizados/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/patologia , Docetaxel/administração & dosagem , Combinação de Medicamentos , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Nivolumabe/administração & dosagem , Nivolumabe/efeitos adversos , Nivolumabe/uso terapêutico , Ácido Oxônico/administração & dosagem , Retratamento , Tegafur/administração & dosagem , Resultado do Tratamento , RamucirumabRESUMO
OBJECTIVES: Nivolumab, an anti-programmed cell death protein 1 (PD-1) monoclonal antibody, has been shown to yield a durable response and significant prolongation of the survival in some patients with non-small-cell lung cancer (NSCLC). However, identification of patients who are likely to respond to nivolumab remains difficult at present. MATERIALS AND METHODS: We conducted a retrospective analysis of the clinical data of 87 consecutive patients with advanced NSCLC seen in clinical practice who received nivolumab monotherapy at the National Cancer Center Hospital in Japan between January 2016 and July 2016 (discovery cohort). In addition, we also collected the clinical data of 75 patients who were administered nivolumab monotherapy between August 2016 and March 2017 (validation cohort). For this study, we focused on the changes in the lymphocyte-to-monocyte ratio (LMR) observed after nivolumab monotherapy. RESULTS: In the discovery cohort, increase (≥10%) of the LMR at 4 weeks after the start of nivolumab monotherapy relative to the pretreatment LMR was positively correlated with an objective response (objective response rate (ORR); 39.4% vs 11.8%, p = 0.0065). When this cutoff value of ≥10% was used, increase of the LMR was significantly associated with a prolonged progression-free survival (PFS) (median PFS [mPFS]; 7.3 months vs 2.5 months, p = 0.0049) and overall survival (OS) (median survival time; 15.6 months vs 8.9 months, p = 0.014). In the validation cohort also, increase of the LMR was significantly associated with higher ORR (50.0% vs 20.0%, p = 0.015) and prolonged PFS (mPFS; not reached vs 3.1 months, p = 0.0092). On the other hand, no such correlation was observed among patients treated with docetaxel. CONCLUSION: A rapid increase of the LMR was significantly associated with the effects of nivolumab monotherapy in our study cohort. Therefore, early change of the LMR may be used as a novel effective surrogate marker to decide on continuation of anti-PD-1 therapy.
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Antineoplásicos/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Imunoterapia/métodos , Neoplasias Pulmonares/tratamento farmacológico , Linfócitos/patologia , Monócitos/patologia , Nivolumabe/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Farmacológicos , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Estudos de Coortes , Feminino , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/mortalidade , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Prognóstico , Estudos Retrospectivos , Análise de SobrevidaRESUMO
BACKGROUND: Ovarian metastases from colorectal cancers are relatively rare. Since most ovarian metastases are associated with metastases at other sites, the prognosis is usually poor. Few reports exist that describe the clinical course of colorectal cancer patients with ovarian metastasis, including the chemotherapy response. METHODS: We retrospectively reviewed the clinical data of patients with ovarian metastases from colorectal cancer treated at the National Cancer Center Hospital, Tokyo, between January 2006 and December 2015. RESULTS: Thirty-seven patients with ovarian metastases received palliative chemotherapy as first-line treatment. The objective response rate for systemic chemotherapy of ovarian metastases was significantly lower than that for other metastatic sites (23.5 vs. 63.6% for first-line, respectively, p = 0.0047). Following chemotherapy, the additional surgical resection of ovarian metastases was positively associated with longer overall survival (OS) compared to no surgical resection (43.1 vs. 17.0 months, respectively, p = 0.0016). Furthermore, cytoreductive surgery was also positively associated with longer OS, especially when other metastatic sites were well controlled. CONCLUSIONS: Ovarian metastases are less responsive to systemic chemotherapy compared to extra-ovarian metastases in patients with relapsed or metastatic colorectal cancer. Multidisciplinary treatment strategy, including systemic chemotherapy and cytoreductive surgery, may contribute to the prolongation of OS.
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Neoplasias Colorretais/patologia , Neoplasias Ovarianas/secundário , Neoplasias Ovarianas/terapia , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Terapia Combinada , Procedimentos Cirúrgicos de Citorredução , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/cirurgia , Estudos Retrospectivos , Resultado do TratamentoRESUMO
The preoptic area (POa) of the rostral diencephalon supplies the neocortex and the amygdala with GABAergic neurons in the developing mouse brain. However, the molecular mechanisms that determine the pathway and destinations of POa-derived neurons have not yet been identified. Here we show that Chicken ovalbumin upstream promoter transcription factor II (COUP-TFII)-induced expression of Neuropilin-2 (Nrp2) and its down-regulation control the destination of POa-derived GABAergic neurons. Initially, a majority of the POa-derived migrating neurons express COUP-TFII and form a caudal migratory stream toward the caudal subpallium. When a subpopulation of cells steers toward the neocortex, they exhibit decreased expression of COUP-TFII and Nrp2. The present findings show that suppression of COUP-TFII/Nrp2 changed the destination of the cells into the neocortex, whereas overexpression of COUP-TFII/Nrp2 caused cells to end up in the medial part of the amygdala. Taken together, these results reveal that COUP-TFII/Nrp2 is a molecular switch determining the pathway and destination of migrating GABAergic neurons born in the POa.
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Encéfalo/metabolismo , Fator II de Transcrição COUP/metabolismo , Diencéfalo/metabolismo , Neurônios GABAérgicos/metabolismo , Neuropilina-2/metabolismo , Tonsila do Cerebelo/embriologia , Tonsila do Cerebelo/metabolismo , Animais , Western Blotting , Encéfalo/embriologia , Fator II de Transcrição COUP/genética , Movimento Celular/genética , Diencéfalo/embriologia , Neurônios GABAérgicos/citologia , Regulação da Expressão Gênica no Desenvolvimento , Hibridização In Situ , Camundongos Endogâmicos ICR , Camundongos Knockout , Microscopia Confocal , Neocórtex/embriologia , Neocórtex/metabolismo , Neuropilina-2/genética , Área Pré-Óptica/embriologia , Área Pré-Óptica/metabolismo , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Técnicas de Cultura de TecidosRESUMO
The mammalian neocortex has a laminar structure that develops in a birth-date-dependent "inside-out" pattern. Its layered structure is established by neuronal migration accompanied by sequential changes in migratory mode regulated by several signaling cascades. Although Reelin was discovered about two decades ago and is one of the best known molecules that is indispensable to the establishment of the "inside-out" neuron layers, the cellular and molecular functions of Reelin in layer formation are still largely unknown. In this review article, we summarize our recent understanding of Reelin's functions during neuronal migration. Reelin acts in at least two different steps of neuronal migration: the final step of neuronal migration (somal/terminal translocation) just beneath the marginal zone (MZ) and the regulation of cell polarity step when the neurons change their migratory mode from multipolar migration to locomotion. During the translocation mode, Reelin activates integrin α5ß1 through an intracellular pathway that triggers the translocation and activates N-cadherin in concert with the nectin-afadin system. Reelin is also involved in the termination of neuronal migration by degrading Dab1 via the SOCS7-Cullin5-Rbx2 system, and Reelin has been found to induce the birth-date-dependent neuronal aggregation in vivo. Based on these findings, we hypothesize that the molecular function of Reelin during neuronal migration is to control cell-adhesiveness during development by regulating the expression/activation of cell adhesion molecules.
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Moléculas de Adesão Celular Neuronais/fisiologia , Movimento Celular/fisiologia , Proteínas da Matriz Extracelular/fisiologia , Mamíferos/anatomia & histologia , Neocórtex/citologia , Neocórtex/crescimento & desenvolvimento , Proteínas do Tecido Nervoso/fisiologia , Neurônios/fisiologia , Serina Endopeptidases/fisiologia , Animais , Humanos , Mamíferos/crescimento & desenvolvimento , Neurogênese , Proteína Reelina , Transdução de Sinais/fisiologiaRESUMO
Birthdate-dependent neuronal layering is fundamental to neocortical functions. The extracellular protein Reelin is essential for the establishment of the eventual neuronal alignments. Although this Reelin-dependent neuronal layering is mainly established by the final neuronal migration step called "terminal translocation" beneath the marginal zone (MZ), the molecular mechanism underlying the control by Reelin of terminal translocation and layer formation is largely unknown. Here, we show that after Reelin binds to its receptors, it activates integrin α5ß1 through the intracellular Dab1-Crk/CrkL-C3G-Rap1 pathway. This intracellular pathway is required for terminal translocation and the activation of Reelin signaling promotes neuronal adhesion to fibronectin through integrin α5ß1. Since fibronectin is localized in the MZ, the activated integrin α5ß1 then controls terminal translocation, which mediates proper neuronal alignments in the mature cortex. These data indicate that Reelin-dependent activation of neuronal adhesion to the extracellular matrix is crucial for the eventual birth-date-dependent layering of the neocortex.
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Moléculas de Adesão Celular Neuronais/metabolismo , Adesão Celular/fisiologia , Movimento Celular/fisiologia , Proteínas da Matriz Extracelular/metabolismo , Regulação da Expressão Gênica/fisiologia , Integrina alfa5beta1/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/fisiologia , Serina Endopeptidases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Análise de Variância , Animais , Adesão Celular/efeitos dos fármacos , Adesão Celular/genética , Moléculas de Adesão Celular Neuronais/efeitos dos fármacos , Moléculas de Adesão Celular Neuronais/genética , Linhagem Celular Transformada , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Eletroporação , Embrião de Mamíferos , Proteínas da Matriz Extracelular/efeitos dos fármacos , Proteínas da Matriz Extracelular/genética , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/genética , Proteínas de Fluorescência Verde/genética , Humanos , Integrina alfa5beta1/genética , Camundongos , Camundongos Endogâmicos ICR , Camundongos Mutantes Neurológicos , Camundongos Transgênicos , Mutação/genética , Proteínas do Tecido Nervoso/efeitos dos fármacos , Proteínas do Tecido Nervoso/genética , Neurônios/efeitos dos fármacos , Proteínas Nucleares , Gravidez , Proteínas Proto-Oncogênicas c-crk/metabolismo , Proteína Reelina , Serina Endopeptidases/efeitos dos fármacos , Serina Endopeptidases/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Córtex Somatossensorial/citologia , Proteínas rap1 de Ligação ao GTP/metabolismoRESUMO
Mammalian neocortex has a laminated structure that develops in a birth-date-dependent "inside-out" pattern. This layered structure is established by neuronal migration with sequential changes of the migratory mode regulated by several signaling cascades, including the Reelin-Disabled homolog 1 (Dab1) pathway. Although the importance of "locomotion," the major migratory mode, has been well established, the physiological significance of the mode change from locomotion to "terminal translocation," the final migratory mode, is unknown. In this study, we found that the outermost region of the mouse cortical plate has several histologically distinct features and named this region the primitive cortical zone (PCZ). Time-lapse analyses revealed that "locomoting" neurons paused transiently just beneath the PCZ before migrating into it by "terminal translocation." Furthermore, whereas Dab1-knockdown (KD) neurons could reach beneath the PCZ, they failed to enter the PCZ, suggesting that the Dab1-dependent terminal translocation is necessary for entry of the neurons into the PCZ. Importantly, sequential in utero electroporation experiments directly revealed that failure of the Dab1-dependent terminal translocation resulted in disruption of the inside-out alignment within the PCZ and that this disrupted pattern was still preserved in the mature cortex. Conversely, Dab1-KD locomoting neurons could pass by both wild-type and Dab1-KD predecessors beneath the PCZ. Our data indicate that the PCZ is a unique environment, passage of neurons through which involves molecularly and behaviorally different migratory mechanisms, and that the migratory mode change from locomotion to terminal translocation just beneath the PCZ is critical for the Dab1-dependent inside-out lamination in the mature cortex.
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Morfogênese/fisiologia , Neocórtex/embriologia , Neocórtex/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Neurogênese/fisiologia , Animais , Movimento Celular , Camundongos , Camundongos Endogâmicos ICR , Neurônios/fisiologia , Proteína ReelinaRESUMO
Neurons in the developing mammalian neocortex form the cortical plate (CP) in an "inside-out" manner; that is, earlier-born neurons form the deeper layers, whereas later-born neurons migrate past the existing layers and form the more superficial layers. Reelin, a glycoprotein secreted by Cajal-Retzius neurons in the marginal zone (MZ), is crucial for this "inside-out" layering, because the layers are inverted in the Reelin-deficient mouse, reeler (Reln(rl)). Even though more than a decade has passed since the discovery of reelin, the biological effect of Reelin on individual migrating neurons remains unclear. In addition, although the MZ is missing in the reeler cortex, it is unknown whether Reelin directly regulates the development of the cell-body-sparse MZ. To address these issues, we expressed Reelin ectopically in the developing mouse cortex, and the results showed that Reelin caused the leading processes of migrating neurons to assemble in the Reelin-rich region, which in turn induced their cell bodies to form cellular aggregates around Reelin. Interestingly, the ectopic Reelin-rich region became cell-body-sparse and dendrite-rich, resembling the MZ, and the late-born neurons migrated past their predecessors toward the central Reelin-rich region within the aggregates, resulting in a birthdate-dependent "inside-out" alignment even ectopically. Reelin receptors and intracellular adaptor protein Dab1 were found to be necessary for formation of the aggregates. The above findings indicate that Reelin signaling is capable of inducing the formation of the dendrite-rich, cell-body-sparse MZ and a birthdate-dependent "inside-out" alignment of neurons independently of other factors/structures near the MZ.
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Moléculas de Adesão Celular Neuronais/metabolismo , Movimento Celular/fisiologia , Proteínas da Matriz Extracelular/metabolismo , Neocórtex/embriologia , Neocórtex/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Neurônios/fisiologia , Serina Endopeptidases/metabolismo , Animais , Moléculas de Adesão Celular Neuronais/genética , Agregação Celular/fisiologia , Linhagem Celular , Dendritos/fisiologia , Proteínas da Matriz Extracelular/genética , Humanos , Camundongos , Camundongos Endogâmicos ICR , Camundongos Transgênicos , Neocórtex/cirurgia , Proteínas do Tecido Nervoso/genética , Proteína Reelina , Serina Endopeptidases/genética , Fatores de TempoRESUMO
Although membrane trafficking pathways are involved in basic cellular functions, the evolutionally expanded number of their related family proteins suggests additional roles for membrane trafficking in higher organisms. Here, we show that several Rab-dependent trafficking pathways differentially participate in neuronal migration, an essential step for the formation of the mammalian-specific six-layered brain structure. In vivo electroporation-mediated suppression of Rab5 or dynamin to block endocytosis caused a severe neuronal migration defect in mouse cerebral cortex. Among many downstream endocytic pathways, suppression of Rab11-dependent recycling pathways exhibited a similar migration disorder, whereas inhibition of Rab7-dependent lysosomal degradation pathways affected only the final phase of neuronal migration and dendrite morphology. Inhibition of Rab5 or Rab11 perturbed the trafficking of N-cadherin, whose suppression also disturbed neuronal migration. Taken together, our findings reveal physiological roles of endocytic pathways, each of which has specific functions in distinct steps of neuronal migration and maturation during mammalian brain formation.
Assuntos
Caderinas/metabolismo , Movimento Celular/fisiologia , Endocitose/fisiologia , Neurônios/fisiologia , Proteínas rab de Ligação ao GTP/metabolismo , Animais , Caderinas/genética , Adesão Celular/fisiologia , Comunicação Celular/fisiologia , Células Cultivadas , Córtex Cerebral/citologia , Córtex Cerebral/crescimento & desenvolvimento , Córtex Cerebral/fisiologia , Dendritos/fisiologia , Dinaminas/genética , Dinaminas/metabolismo , Lisossomos/enzimologia , Lisossomos/fisiologia , MAP Quinase Quinase 4/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Neurônios/citologia , Transdução de Sinais , Proteínas rab de Ligação ao GTP/genética , Proteínas rab5 de Ligação ao GTP/genética , Proteínas rab5 de Ligação ao GTP/metabolismo , proteínas de unión al GTP Rab7RESUMO
Neuronal migration is essential for proper cortical layer formation and brain function, because migration defects result in neurological disorders such as mental retardation and epilepsy. Neuronal migration is divided into several contiguous steps: early phase (multipolar mode), locomotion mode, and terminal translocation mode. The locomotion mode covers most of the migration route and thereby is the main contributor to cortical layer formation. However, analysis of the molecular mechanisms regulating this mode is difficult due to the secondary effects of defects at the early phase of migration. In this study, we established an ex vivo chemical inhibitor screening, allowing us to directly analyze the locomotion mode of migration. Roscovitine and PP2, inhibitors for Cdk5 and Src family kinases, respectively, suppressed the locomotion mode of migration. In line with this, a small percentage of Cdk5- or Src family kinase (Fyn)-knockdown cells exhibited locomoting morphology but retarded migration, although the majority of cells were stalled at the early phase of migration. We also showed that rottlerin, widely used as a specific inhibitor for protein kinase Cdelta (PKCdelta), suppressed the locomotion mode. Unexpectedly, however, the dominant-negative form as well as RNA interference for PKCdelta hardly affected the locomotion, whereas they may disturb terminal translocation. In addition, we found JNK to be a potential downstream target of rottlerin. Taken together, our novel chemical inhibitor screening provides evidence that Cdk5 and Src family kinases regulate the locomotion mode of neuronal migration. It also uncovered roles for Fyn and PKCdelta in the early and final phases of migration, respectively.