Satellite cells are quiescent skeletal muscle specific stem cells that are activated in response to injury to aid in muscle repair and regeneration. The interaction of hepatocyte growth factor (HGF) with these cells is crucial for their activation. However, to date, research on the effect of HGF on skeletal muscle satellite cells has yielded conflicting data. Clarity is therefore required as to its effect on downstream myogenic processes. Furthermore, mouse and rat cell lines and primary culture have been widely used for in vitro studies to investigate the effect of HGF on skeletal muscle physiology and disease; very few studies have been carried out in primary cultured human skeletal myoblasts. As a result, we aimed to investigate and compare the effect of HGF (2, 10 and 50 ng/ml) on mouse C2C12 myoblast versus primary culture human skeletal myoblast (HSkM) proliferation, migration and differentiation. Proliferation was assessed via both cell counts and crystal violet assay, while migration was investigated using the scratch assay. Differentiation was determined via analysis of expression patterns of transcription factors implicated in myogenic commitment (i.e. Pax7, MyoD) as well expression of the structural protein Myosin Heavy Chain (MyHC). We demonstrate a dose-dependent effect of HGF on myoblast proliferation whereby an increase in proliferation was detected in response to 2 ng/ml HGF, whilst 10 ng/ml HGF resulted in a reduction in proliferation capacity of both C2C12 and HSkM myoblasts. Interestingly, the reduction in proliferation in response to 10 ng/ml HGF was accompanied by a down-regulation in Pax7 expression during differentiation of both mouse and human myoblasts. HGF also affected myoblast migration and differentiation in a dose-dependent manner that was inversely proportional to proliferation. HGF (10 ng/ml) stimulated an increase in myogenic commitment and terminal differentiation of C2C12 and HSkM myoblasts as reflected by the increased percentage MyoD positive cells, improved fusion and greater MyHC expression. C2C12 myoblast migration was also stimulated at this HGF concentration, but reduced in response to the lower HGF (2 ng/ml) dose. The decrease in proliferation following incubation with 10 ng/ml HGF, allows cells to exit proliferation into either a mode of migration or differentiation. Our data confirms the importance of HGF during myogenesis and highlights the sensitivity of satellite cells to changing HGF concentration. This has implications in the regulation of skeletal muscle wound repair. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Tez (Tıpta Uzmanlık) - Süleyman Demirel Üniversitesi, Tıp Fakültesi, Göğüs Hastalıkları Anabilim Dalı, 2006. / Bibliyografya var.

Diss. (sammanfattning) Linköping : Univ., 2002. / Härtill 6 uppsatser.

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Includes bibliographical references (leaves 293-348). Issued in print and online. Available via ProQuest Digital Dissertations.

No description available.

As neoplasias de glândula salivar (NGS) são tumores raros que despertam interesse por sua diversidade histopatológica e comportamento clínico. A compreensão da patobiologia assim como, dos mecanismos envolvidos no comportamento invasivo destas lesões é necessária para melhor entender a biologia das NGS e posteriormente delinear novas estratégias terapêuticas. A presente tese foi dividida em dois artigos. O objetivo do primeiro estudo foi descrever os dados demográficos, clinicopatológicos e de prognóstico das NGS diagnosticados em um centro de atenção terciário. Para tal, foi realizada uma análise retrospectiva utilizando os dados de arquivos e de prontuários. Foram identificados 109 casos de NGS cuja média de idade dos pacientes foi de 46.47 anos e a relação homens:mulheres foi de 0.94:1. As glândulas salivares maiores foram mais acometidas (75.2%) e os tumores benignos os mais prevalentes (75.2%) sendo o adenoma pleomórfico o tumor benigno mais comum e o carcinoma adenóide cístico o principal maligno. O objetivo do segundo estudo foi analizar o padrão de expressão da via de sinalização do HGF/c-Me/PI3K em NGS e correlacionar com o perfi proliferativo e desfechos clínicos das lesões. Foram construídos microarranjos de tecido (TMAs) de 93 casos de NGs e as lâminas foram submetidas a análise imunoistoquímica para HGF, p-Met, p-Akt e Ki67. Foi observada maior expressão de HGF nos tumores benignos (p=0.04), enquanto que as protínas p-Met (p=0.03), p-Akt (p=0.00) e Ki-67 (p=0.00) foram mais expressas nos tumores malignos. Nas neoplasias malignas houve maior ativação da via HGF observada pela maior expressão do seu receptor fosforilado (p-Met) bem como, maior ativação da via do PI3k pela fosforilação de Akt (p-Akt) resultando em um maior perfil proliferativo. Pode-se concluir que a via de sinalização do HGF/c-Met/PI3k parece estar ativa nas NGS regulando a proliferação especialmente nas neoplasias malignas. / Salivary gland tumors (SGT) are rare yet interesting neoplasms due to their histopatological diversity and clinical behavior. Understanding the pathobiology as well as the mechanisms involved in the invasive behavior of these lesions is needed to better comprehend the biology of SGT and further delineate new therapeutic strategies. This thesis was divided in two papers. The aim of the first study was to describe the demographic, clincopathological and prognostic data of SGT diagnosed in a tertiary care center. For this purpose, a retrospective analysis using data from the archives and records was performed. One hundred and nine cases of SGT were identified. The patients mean age was 46.47 years and the male:female ratio was 0.91:1. The major salivary glands were the most affected (75.2%) and the benign SGT were more prevalent (78%) being pleomorphic adenoma the most common benign tumor and adenoid cystic carcinoma the most common malignant tumor. The objective of the second study was to analyze the expression pattern of HGF/c-Met/PI3K signaling pathway in SGT and correlate the findings with the proliferative profile and clinical outcomes of cases. Tissue microarrays (TMAs) of 93 cases of SGT were constructed; the slides were submitted to immunohistochemical analysis for HGF, p-Met, p-Akt and Ki-67. Increased expression of HGF was observed in benign tumors (p = 0.04), while p-Met (P = 0.03), p-Akt (p = 0:00) and Ki-67 (p = 0:00) were most expressed in malignant tumors. In salivary glands carcinomas there was a higher activation of the HGF pathway observed by the higher expression of its phosporylated receptor (p-Met) as well as the higher activation of PI3k pathway through Akt (p-Akt) phosphorilation, resulting in a higher proliferative profile. It can be concluded that HGF/c-Met/PI3K signaling pathway appears to be active in SGT regulating the proliferation specially in malignant tumors.

As neoplasias de glândula salivar (NGS) são tumores raros que despertam interesse por sua diversidade histopatológica e comportamento clínico. A compreensão da patobiologia assim como, dos mecanismos envolvidos no comportamento invasivo destas lesões é necessária para melhor entender a biologia das NGS e posteriormente delinear novas estratégias terapêuticas. A presente tese foi dividida em dois artigos. O objetivo do primeiro estudo foi descrever os dados demográficos, clinicopatológicos e de prognóstico das NGS diagnosticados em um centro de atenção terciário. Para tal, foi realizada uma análise retrospectiva utilizando os dados de arquivos e de prontuários. Foram identificados 109 casos de NGS cuja média de idade dos pacientes foi de 46.47 anos e a relação homens:mulheres foi de 0.94:1. As glândulas salivares maiores foram mais acometidas (75.2%) e os tumores benignos os mais prevalentes (75.2%) sendo o adenoma pleomórfico o tumor benigno mais comum e o carcinoma adenóide cístico o principal maligno. O objetivo do segundo estudo foi analizar o padrão de expressão da via de sinalização do HGF/c-Me/PI3K em NGS e correlacionar com o perfi proliferativo e desfechos clínicos das lesões. Foram construídos microarranjos de tecido (TMAs) de 93 casos de NGs e as lâminas foram submetidas a análise imunoistoquímica para HGF, p-Met, p-Akt e Ki67. Foi observada maior expressão de HGF nos tumores benignos (p=0.04), enquanto que as protínas p-Met (p=0.03), p-Akt (p=0.00) e Ki-67 (p=0.00) foram mais expressas nos tumores malignos. Nas neoplasias malignas houve maior ativação da via HGF observada pela maior expressão do seu receptor fosforilado (p-Met) bem como, maior ativação da via do PI3k pela fosforilação de Akt (p-Akt) resultando em um maior perfil proliferativo. Pode-se concluir que a via de sinalização do HGF/c-Met/PI3k parece estar ativa nas NGS regulando a proliferação especialmente nas neoplasias malignas. / Salivary gland tumors (SGT) are rare yet interesting neoplasms due to their histopatological diversity and clinical behavior. Understanding the pathobiology as well as the mechanisms involved in the invasive behavior of these lesions is needed to better comprehend the biology of SGT and further delineate new therapeutic strategies. This thesis was divided in two papers. The aim of the first study was to describe the demographic, clincopathological and prognostic data of SGT diagnosed in a tertiary care center. For this purpose, a retrospective analysis using data from the archives and records was performed. One hundred and nine cases of SGT were identified. The patients mean age was 46.47 years and the male:female ratio was 0.91:1. The major salivary glands were the most affected (75.2%) and the benign SGT were more prevalent (78%) being pleomorphic adenoma the most common benign tumor and adenoid cystic carcinoma the most common malignant tumor. The objective of the second study was to analyze the expression pattern of HGF/c-Met/PI3K signaling pathway in SGT and correlate the findings with the proliferative profile and clinical outcomes of cases. Tissue microarrays (TMAs) of 93 cases of SGT were constructed; the slides were submitted to immunohistochemical analysis for HGF, p-Met, p-Akt and Ki-67. Increased expression of HGF was observed in benign tumors (p = 0.04), while p-Met (P = 0.03), p-Akt (p = 0:00) and Ki-67 (p = 0:00) were most expressed in malignant tumors. In salivary glands carcinomas there was a higher activation of the HGF pathway observed by the higher expression of its phosporylated receptor (p-Met) as well as the higher activation of PI3k pathway through Akt (p-Akt) phosphorilation, resulting in a higher proliferative profile. It can be concluded that HGF/c-Met/PI3K signaling pathway appears to be active in SGT regulating the proliferation specially in malignant tumors.

As neoplasias de glândula salivar (NGS) são tumores raros que despertam interesse por sua diversidade histopatológica e comportamento clínico. A compreensão da patobiologia assim como, dos mecanismos envolvidos no comportamento invasivo destas lesões é necessária para melhor entender a biologia das NGS e posteriormente delinear novas estratégias terapêuticas. A presente tese foi dividida em dois artigos. O objetivo do primeiro estudo foi descrever os dados demográficos, clinicopatológicos e de prognóstico das NGS diagnosticados em um centro de atenção terciário. Para tal, foi realizada uma análise retrospectiva utilizando os dados de arquivos e de prontuários. Foram identificados 109 casos de NGS cuja média de idade dos pacientes foi de 46.47 anos e a relação homens:mulheres foi de 0.94:1. As glândulas salivares maiores foram mais acometidas (75.2%) e os tumores benignos os mais prevalentes (75.2%) sendo o adenoma pleomórfico o tumor benigno mais comum e o carcinoma adenóide cístico o principal maligno. O objetivo do segundo estudo foi analizar o padrão de expressão da via de sinalização do HGF/c-Me/PI3K em NGS e correlacionar com o perfi proliferativo e desfechos clínicos das lesões. Foram construídos microarranjos de tecido (TMAs) de 93 casos de NGs e as lâminas foram submetidas a análise imunoistoquímica para HGF, p-Met, p-Akt e Ki67. Foi observada maior expressão de HGF nos tumores benignos (p=0.04), enquanto que as protínas p-Met (p=0.03), p-Akt (p=0.00) e Ki-67 (p=0.00) foram mais expressas nos tumores malignos. Nas neoplasias malignas houve maior ativação da via HGF observada pela maior expressão do seu receptor fosforilado (p-Met) bem como, maior ativação da via do PI3k pela fosforilação de Akt (p-Akt) resultando em um maior perfil proliferativo. Pode-se concluir que a via de sinalização do HGF/c-Met/PI3k parece estar ativa nas NGS regulando a proliferação especialmente nas neoplasias malignas. / Salivary gland tumors (SGT) are rare yet interesting neoplasms due to their histopatological diversity and clinical behavior. Understanding the pathobiology as well as the mechanisms involved in the invasive behavior of these lesions is needed to better comprehend the biology of SGT and further delineate new therapeutic strategies. This thesis was divided in two papers. The aim of the first study was to describe the demographic, clincopathological and prognostic data of SGT diagnosed in a tertiary care center. For this purpose, a retrospective analysis using data from the archives and records was performed. One hundred and nine cases of SGT were identified. The patients mean age was 46.47 years and the male:female ratio was 0.91:1. The major salivary glands were the most affected (75.2%) and the benign SGT were more prevalent (78%) being pleomorphic adenoma the most common benign tumor and adenoid cystic carcinoma the most common malignant tumor. The objective of the second study was to analyze the expression pattern of HGF/c-Met/PI3K signaling pathway in SGT and correlate the findings with the proliferative profile and clinical outcomes of cases. Tissue microarrays (TMAs) of 93 cases of SGT were constructed; the slides were submitted to immunohistochemical analysis for HGF, p-Met, p-Akt and Ki-67. Increased expression of HGF was observed in benign tumors (p = 0.04), while p-Met (P = 0.03), p-Akt (p = 0:00) and Ki-67 (p = 0:00) were most expressed in malignant tumors. In salivary glands carcinomas there was a higher activation of the HGF pathway observed by the higher expression of its phosporylated receptor (p-Met) as well as the higher activation of PI3k pathway through Akt (p-Akt) phosphorilation, resulting in a higher proliferative profile. It can be concluded that HGF/c-Met/PI3K signaling pathway appears to be active in SGT regulating the proliferation specially in malignant tumors.

Orientador: Mario José Abdalla Saad / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-21T17:03:51Z (GMT). No. of bitstreams: 1 Araujo_TiagoGomes_D.pdf: 9136785 bytes, checksum: 25c68d3dd56714d164986b415f98070d (MD5) Previous issue date: 2012 / Resumo: A resistência à insulina está presente na obesidade e na diabetes tipo 2, e está associada à hiperplasia das ilhotas pancreáticas e hiperinsulinemia como resposta compensatória, entretanto, as forças motrizes por trás desse mecanismo compensatório não são totalmente compreendidos. Dados anteriores sugeriram o envolvimento de um fator circulante desconhecido que na resistência à insulina atua como um fator de crescimento das células ?. Neste contexto, procurando por candidatos a serem este fator circulante, percebemos que o fator de crescimento de hepatócitos (HGF) é um forte candidato a ser este elo entre a resistência à insulina e o aumento da massa de ilhotas / hiperinsulinemia. Nossa abordagem teve como objetivo mostrar uma possível relação de causa-efeito entre o aumento dos níveis circulantes de HGF e a hiperplasia da ilhota / hiperinsulinemia compensatória, assim mostrando a força da associação. Ainda, se esta associação, apresenta ou não uma resposta dose-dependente, temporalidade, consistência, plausibilidade e reversibilidade. Nesse sentido, os nossos dados mostraram: a) uma correlação forte e consistente entre o HGF e o mecanismo de compensação em três modelos animais de resistência à insulina; b) o HGF aumenta a massa de célula ? de uma forma dose-dependente; c) o bloqueio do HGF interrompe os mecanismos de compensação; d) o aumento nos níveis de HGF precede a resposta compensatória associada com a resistência à insulina, indicando que estes eventos ocorrem em um modo sequencial. Além disso, o bloqueio do receptor de HGF (Met) piorou a já prejudicada sinalização da insulina no fígado de ratos obesos induzidos por dieta. Em geral, os nossos dados indicam que o HGF é um fator de crescimento que desempenha um papel fundamental no aumento da massa de ilhotas e hiperinsulinemia em ratos obesos induzidos por dieta, e sugerem um efeito protetor da interação HGF-Met na sinalização de insulina no fígado / Abstract: Insulin resistance is present in obesity and in type 2 diabetes, and is associated with islet cell hyperplasia and hyperinsulinemia but the driving forces behind this compensatory mechanism are incompletely understood. Previous data have suggested the involvement of an unknown circulating insulin resistance-related ?-cell growth-factor. In this context, looking for candidates to be a circulating factor, we realized that hepatocyte growth factor (HGF) is a strong candidate as a link between insulin resistance and increased mass of islets/hyperinsulinemia. Our approach aimed to show a possible cause-effect relationship between increase in circulating HGF levels and compensatory islet hyperplasia/hyperinsulinemia by showing the strength of the association, whether or not is a dose-dependent response, the temporality, consistency, plausibility and reversibility of the association. In this regard, our data showed: a) a strong and consistent correlation between HGF and the compensatory mechanism in three animal models of insulin resistance; b) HGF increases ?-cell mass in a dose-dependent manner; c) blocking HGF shuts down the compensatory mechanisms; d) an increase in HGF levels seems to precede the compensatory response associated with insulin resistance, indicating that these events occur in a sequential mode. Additionally, blockages of HGF receptor (Met) worsen the impaired insulin-induced insulin signaling in liver of diet-induced obesity rats. Overall, our data indicate that HGF is a growth factor playing a key role in islet mass increase and hyperinsulinemia in diet-induced obesity rats, and suggest a protective effect of the HGF-Met axis on insulin signaling in the liver / Doutorado / Medicina Experimental / Doutor em Ciências

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23368号 / 医博第4737号 / 新制||医||1051(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 川口 義弥, 教授 妹尾 浩, 教授 稲垣 暢也 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM