京都大学 / 新制・課程博士 / 博士(医学) / 甲第24508号 / 医博第4950号 / 新制||医||1064(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 平井 豊博, 教授 武藤 学, 教授 中島 貴子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Thesis (Ph. D.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains vi, 130 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

As partículas eliminadas na exaustão do diesel (DEP) são importantes fontes diárias de partículas inaladas, responsáveis por gerar espécies reativas de oxigênio no sistema respiratório, fazendo com que as células ativem mecanismos de defesa, como o sistema Keap1-Nrf2 e a autofagia. Para investigar o papel do Nrf2 no processo de autofagia induzida pelas DEPs, BEAS-2B foram expostas às DEP, coletadas diretamente de um motor a diesel. BEAS-2B foram tratadas com sulforafano, bafilomicina e EBSS para testar a relação entre as vias autofágica e antioxidante. A quantidade relativa de mRNA foi verificada por RT-PCR para os seguintes genes: Nrf2, NQO1, HO-1, p62, Atg5 e LCB3. A seguir, BEAS-2B foram transfectadas com RNA silenciador (siRNA) para Nrf2, expostas ou não às DEPs (10 e 50 micro g/mL por 1h e 2 h), e mRNA detectado por RT-PCR e Western blot para proteínas. Bafilomicina (inibidor de autofagia) mostrou uma diminuição significativa nos marcadores antioxidantes Nrf2 (p = 0,024), HO-1 (p = 0,002) e NQO1 (p = 0,003), enquanto sulforafano (ativador de Nrf2) aumentou os marcadores autofágicos LC3B (p = 0,004) e Atg5 (p = 0,007). BEAS-2B expostas às DEP na concentração de 50 micro g/mL por 2hs mostraram um aumento significativo nos genes autofágicos LC3B (p = 0,018) e p62 (p = 0,007) e nos genes da via antioxidante Nrf2 (p = 0,007) e NQO1 (p = 0,025). Houve uma diminuição significativa no mRNA de LC3B (p < 0,001), p62 (p = 0,001) e Atg5 (p = 0,024) nas células transfectadas com siRNA, expostas ou não à DEP. Western blotting mostrou uma redução das proteínas Nrf2, p62 e LC3II nas BEAS-2B siRNA, indicando que a exposição ao silenciamento de Nrf2 modificou a expressão de marcadores de autofagia (R < 1). Os resultados deste estudo mostram que, em células brônquicas expostas às DEP, o sistema Nrf2 e a autofagia trabalham em conjunto para tentar manter a homeostase celular / Diesel Exhaust Particles (DEPs) are main sources of daily inhaled particles, responsible for generating reactive oxygen species in the respiratory system, and causing the cells to activate defense mechanisms, such as the Keap1-Nrf2 system and autophagy. In order to investigate the role of Nrf2 in Dep-induced autophagy, BEAS-2B cells collected directly from a diesel engine were exposed to DEP and treated with sulforaphane, bafilomycin and BESS to test the relationship between autophagic and antioxidant pathways. The relative amount of mRNA was verified by RT-PCR for the following genes: Nrf2, NQO1, HO-1, p62, Atg5 and LCB3. Next, BEAS-2B cells were transfected with silencer RNA (siRNA) specific to Nrf2, exposed or not to DEPs (10 and 50 micro g/mL 1h and 2hs), and mRNA detected by RT-PCR and Western blotting for protein. Bafilomycin ( autophagy inhibitor) showed a significant decrease in the antioxidant markers Nrf2 (p=0.024), HO-1 (p = 0.002) and NQO1 (p = 0.003), whereas sulforaphane (Nrf2 activator) increased the expression levels of autophagic markers LC3B (p=0.004) and Atg5 (p=0.007). BEAS-2B exposed to DEP at a concentration of 50 micro g/mL for 2hs showed a significant increase in autophagic genes LC3B (p=0.018) and p62 (p=0.007),and in the antioxidant pathway markers Nrf2 (p=0.007) and NQO1 (p=0.025). There was a significant decrease in mRNA of the LC3B (p < 0.001), p62 (p=0.001) and Atg5 (p=0.024) in cells transfected with siRNA, exposed or not to DEP. Western blotting showed a reduction of Nrf2, p62 and LC3II proteins in BEAS-2B transfected with siRNA, indicating that Nrf2 silencedexposed to DEP modulated the expression of autophagy markers (R < 1). The results of this study show that, in bronchial cells exposed to DEP, the Nrf2 system and autophagy work together in order to try to maintain cellular homeostasis

As partículas eliminadas na exaustão do diesel (DEP) são importantes fontes diárias de partículas inaladas, responsáveis por gerar espécies reativas de oxigênio no sistema respiratório, fazendo com que as células ativem mecanismos de defesa, como o sistema Keap1-Nrf2 e a autofagia. Para investigar o papel do Nrf2 no processo de autofagia induzida pelas DEPs, BEAS-2B foram expostas às DEP, coletadas diretamente de um motor a diesel. BEAS-2B foram tratadas com sulforafano, bafilomicina e EBSS para testar a relação entre as vias autofágica e antioxidante. A quantidade relativa de mRNA foi verificada por RT-PCR para os seguintes genes: Nrf2, NQO1, HO-1, p62, Atg5 e LCB3. A seguir, BEAS-2B foram transfectadas com RNA silenciador (siRNA) para Nrf2, expostas ou não às DEPs (10 e 50 micro g/mL por 1h e 2 h), e mRNA detectado por RT-PCR e Western blot para proteínas. Bafilomicina (inibidor de autofagia) mostrou uma diminuição significativa nos marcadores antioxidantes Nrf2 (p = 0,024), HO-1 (p = 0,002) e NQO1 (p = 0,003), enquanto sulforafano (ativador de Nrf2) aumentou os marcadores autofágicos LC3B (p = 0,004) e Atg5 (p = 0,007). BEAS-2B expostas às DEP na concentração de 50 micro g/mL por 2hs mostraram um aumento significativo nos genes autofágicos LC3B (p = 0,018) e p62 (p = 0,007) e nos genes da via antioxidante Nrf2 (p = 0,007) e NQO1 (p = 0,025). Houve uma diminuição significativa no mRNA de LC3B (p < 0,001), p62 (p = 0,001) e Atg5 (p = 0,024) nas células transfectadas com siRNA, expostas ou não à DEP. Western blotting mostrou uma redução das proteínas Nrf2, p62 e LC3II nas BEAS-2B siRNA, indicando que a exposição ao silenciamento de Nrf2 modificou a expressão de marcadores de autofagia (R < 1). Os resultados deste estudo mostram que, em células brônquicas expostas às DEP, o sistema Nrf2 e a autofagia trabalham em conjunto para tentar manter a homeostase celular / Diesel Exhaust Particles (DEPs) are main sources of daily inhaled particles, responsible for generating reactive oxygen species in the respiratory system, and causing the cells to activate defense mechanisms, such as the Keap1-Nrf2 system and autophagy. In order to investigate the role of Nrf2 in Dep-induced autophagy, BEAS-2B cells collected directly from a diesel engine were exposed to DEP and treated with sulforaphane, bafilomycin and BESS to test the relationship between autophagic and antioxidant pathways. The relative amount of mRNA was verified by RT-PCR for the following genes: Nrf2, NQO1, HO-1, p62, Atg5 and LCB3. Next, BEAS-2B cells were transfected with silencer RNA (siRNA) specific to Nrf2, exposed or not to DEPs (10 and 50 micro g/mL 1h and 2hs), and mRNA detected by RT-PCR and Western blotting for protein. Bafilomycin ( autophagy inhibitor) showed a significant decrease in the antioxidant markers Nrf2 (p=0.024), HO-1 (p = 0.002) and NQO1 (p = 0.003), whereas sulforaphane (Nrf2 activator) increased the expression levels of autophagic markers LC3B (p=0.004) and Atg5 (p=0.007). BEAS-2B exposed to DEP at a concentration of 50 micro g/mL for 2hs showed a significant increase in autophagic genes LC3B (p=0.018) and p62 (p=0.007),and in the antioxidant pathway markers Nrf2 (p=0.007) and NQO1 (p=0.025). There was a significant decrease in mRNA of the LC3B (p < 0.001), p62 (p=0.001) and Atg5 (p=0.024) in cells transfected with siRNA, exposed or not to DEP. Western blotting showed a reduction of Nrf2, p62 and LC3II proteins in BEAS-2B transfected with siRNA, indicating that Nrf2 silencedexposed to DEP modulated the expression of autophagy markers (R < 1). The results of this study show that, in bronchial cells exposed to DEP, the Nrf2 system and autophagy work together in order to try to maintain cellular homeostasis

No / Flavonoids are plant-derived polyphenolic compounds with neuroprotective properties. Recent work suggests that, in addition to acting as hydrogen donors, they activate protective signalling pathways. The anti-oxidant response element (ARE) promotes the expression of protective proteins including those required for glutathione synthesis (xCT cystine antiporter, gamma-glutamylcysteine synthetase and glutathione synthase). The use of a luciferase reporter (ARE-luc) assay showed that the dietary flavan-3-ol (-)epicatechin activates this pathway in primary cortical astrocytes but not neurones. We also examined the distribution of NF-E2-related factor-2 (Nrf2), a key transcription factor in ARE-mediated gene expression. We found, using immunocytochemistry, that Nrf2 accumulated in the nuclei of astrocytes following exposure to tert-butylhydroquinone (100 microM) and (-)epicatechin (100 nM). (-)Epicatechin signalling via Nrf2 was inhibited by wortmannin implicating a phosphatidylinositol 3-kinase-dependent pathway. Finally, (-)epicatechin increased glutathione levels in astrocytes consistent with an up-regulation of ARE-mediated gene expression. Together, this suggests that flavonoids may be cytoprotective by increasing anti-oxidant gene expression.