As espécies de Candida são patógenos oportunistas e as infecções nas cavidades bucais causadas por este gênero são comuns em pacientes com fatores predisponentes, entre eles imussuprimidos, diabéticos e usuários de próteses dentais. No Brasil o índice de endentados é elevado sendo necessária a utilização de próteses bucais, que são locais favoráveis à colonização de microrganismos e o desenvolvimento de biofilme. A utilização de antissépticos como medida complementar na higiene oral é cada vez mais difundida. O objetivo deste trabalho foi detectar em amostras de C. albicans e C. não-albicans, isoladas da saliva de portadores de próteses bucais, os fatores de virulência, proteinase e biofilme e genes relacionados à proteinase (SAP1, SAP3) e à adesão (ALS1 e ALS3) e avaliar a atividade antifúngica in vitro de três formulações comerciais à base de clorexidina 0,12%, cetilpiridínio 0,07% e 0,075% frente aos isolados de Candida e biofilmes. Foram coletadas amostras de saliva de 70 pacientes usuários de próteses bucais. As leveduras foram isoladas em meio de CHROMagar® Candida e identificadas pela metodologia clássica e a confirmação de C. albicans por biologia molecular (PCR). Leveduras do gênero Candida foram isoladas de 32 (45,7%) amostras. Destas foram identificadas: C. albicans (29), C. krusei (5), C. glabrata (4), C. tropicalis (3) e C. parapsilosis (2), totalizando 43 leveduras entre monoculturas e culturas mistas. Os genes pesquisados foram detectados somente em amostras de C. albicans, os genes ALS2, ALS3 e SAP3 foram identificados em 86% dos isolados e o SAP1 em 93%. A atividade de proteinase entre os dos isolados de C. albicans foi de 72,4% e entre das espécies de C. não-albicans 35,7%. A de formação de biofilme sobre placas de 96 poços, e após coloração com XTT, demonstrou que a maioria dos isolados de Candida e todas as culturas mistas desenvolveram biofilmes em 24 horas. A atividade de três antissépticos frente as leveduras foi de <=1,25%, equivalente a uma diluição de 1:80 do antisséptico. Concluímos os três antissépticos também foram eficazes frente aos biofilmes de monoculturas e culturas mistas, as cepas de C. albicans continua sendo a espécie prevalente na cavidade bucal, os genes SAP1, SAP3, ALS2 e ALS3 estão presentes na maioria dos isolados de C. albicans, nestas amostras a maioria foram proteinase e biofilme positivos. A atividade de proteinase foi superior nas espécies de C. albicans em comparação com C. não-albicans. Os biofilmes das espécies de Candida quando formados em culturas mistas se desenvolvem mais em comparação com a formação de biofilme em monocultura. As três formulações de antissépticos foram eficazes contra todos isolados de leveduras em forma planctônica e na maioria dos biofilmes. / Candida species are opportunistic pathogens and infections in the oral cavity caused by these yeasts are common in patients with predisposing factors, such as diabetic or immunocompromised individuals with dental prosthesis. In Brazil, the number of toothless patients is high and the use of dental prosthesis is common, which represents a niche for colonization and formation of microbial biofilms in the oral cavity. The use of mouthwashes to aid in the oral hygiene has increased. The objective of this research was to isolate C. albicans and C. non-albicans from saliva of dental prosthesis users and to evaluate the isolates for the presence of virulence factors, proteinase production, biofilm formation and to search for genes encoding for proteinases (SAP1, SAP3) and adhesion factors (ALS1 and ALS3). Another objective was to evaluate in vitro the antifungal activity of three commercial mouthwashes containing 0.12% chlorhexidine and 0.07% or 0.075% cetylpyridinium, against planktonic Candida sp. cultures and in biofilms. Saliva samples of 70 patients with dental prosthesis were collected, the yeasts were isolated on CHOMagar® Candida and identified by classical biochemical tests combined with molecular test (PCR) for confirmation of C. albicans. Yeasts of Candida genus were isolated from 32 samples (45.7%) and were identified as C. albicans (29), C. krusei (5), C. glabrata (4), C. tropicalis (3) and C. parapsilosis (2), with a total of 43 yeasts, including mono and mixed cultures. The genes studied were detected only in C. albicans: ALS2, ALS3 and SAP3 genes were detected in 86% of the isolates and SAP1 in 93%. The proteinase activity among the isolates of C. albicans was 72.4% and among the species of C. non-albicans it was 35.7%. Assay done with cultivation in 96-wells microplates and staining with XTT, showed the majority of Candida isolates and all the mixed cultures were able to form biofilms within 24h. The activity of the three mouthwashes towards the yeasts was < 1.25%, equivalent to a dilution of 1:80 of the formulation. The three mouthwashes tested were also active against mono or multispecies biofilms. In conclusion, it was shown C. albicans is the most prevalent species. The genes SAP1, SAP3, ALS2 and ALS3 are present in the majority of C. albicans isolates, which were also positive for proteinase and biofilm formation. There was more proteinase activity in C. albicans in comparison with C. non-albicans. The biofilms of Candida species grew better in mixed cultures than in monoculture. The three commercial mouthwashes formulations were effective against all the yeast isolates in planktonic growth and they also inhibited the majority of yeasts in biofilm. Future work is needed to completely elucidate the role of Candida species in biofilms of oral cavity. It is also interesting to propose studies to standardize sensitivity tests for mono and multi-species biofilms.

As espécies de Candida são patógenos oportunistas e as infecções nas cavidades bucais causadas por este gênero são comuns em pacientes com fatores predisponentes, entre eles imussuprimidos, diabéticos e usuários de próteses dentais. No Brasil o índice de endentados é elevado sendo necessária a utilização de próteses bucais, que são locais favoráveis à colonização de microrganismos e o desenvolvimento de biofilme. A utilização de antissépticos como medida complementar na higiene oral é cada vez mais difundida. O objetivo deste trabalho foi detectar em amostras de C. albicans e C. não-albicans, isoladas da saliva de portadores de próteses bucais, os fatores de virulência, proteinase e biofilme e genes relacionados à proteinase (SAP1, SAP3) e à adesão (ALS1 e ALS3) e avaliar a atividade antifúngica in vitro de três formulações comerciais à base de clorexidina 0,12%, cetilpiridínio 0,07% e 0,075% frente aos isolados de Candida e biofilmes. Foram coletadas amostras de saliva de 70 pacientes usuários de próteses bucais. As leveduras foram isoladas em meio de CHROMagar® Candida e identificadas pela metodologia clássica e a confirmação de C. albicans por biologia molecular (PCR). Leveduras do gênero Candida foram isoladas de 32 (45,7%) amostras. Destas foram identificadas: C. albicans (29), C. krusei (5), C. glabrata (4), C. tropicalis (3) e C. parapsilosis (2), totalizando 43 leveduras entre monoculturas e culturas mistas. Os genes pesquisados foram detectados somente em amostras de C. albicans, os genes ALS2, ALS3 e SAP3 foram identificados em 86% dos isolados e o SAP1 em 93%. A atividade de proteinase entre os dos isolados de C. albicans foi de 72,4% e entre das espécies de C. não-albicans 35,7%. A de formação de biofilme sobre placas de 96 poços, e após coloração com XTT, demonstrou que a maioria dos isolados de Candida e todas as culturas mistas desenvolveram biofilmes em 24 horas. A atividade de três antissépticos frente as leveduras foi de <=1,25%, equivalente a uma diluição de 1:80 do antisséptico. Concluímos os três antissépticos também foram eficazes frente aos biofilmes de monoculturas e culturas mistas, as cepas de C. albicans continua sendo a espécie prevalente na cavidade bucal, os genes SAP1, SAP3, ALS2 e ALS3 estão presentes na maioria dos isolados de C. albicans, nestas amostras a maioria foram proteinase e biofilme positivos. A atividade de proteinase foi superior nas espécies de C. albicans em comparação com C. não-albicans. Os biofilmes das espécies de Candida quando formados em culturas mistas se desenvolvem mais em comparação com a formação de biofilme em monocultura. As três formulações de antissépticos foram eficazes contra todos isolados de leveduras em forma planctônica e na maioria dos biofilmes. / Candida species are opportunistic pathogens and infections in the oral cavity caused by these yeasts are common in patients with predisposing factors, such as diabetic or immunocompromised individuals with dental prosthesis. In Brazil, the number of toothless patients is high and the use of dental prosthesis is common, which represents a niche for colonization and formation of microbial biofilms in the oral cavity. The use of mouthwashes to aid in the oral hygiene has increased. The objective of this research was to isolate C. albicans and C. non-albicans from saliva of dental prosthesis users and to evaluate the isolates for the presence of virulence factors, proteinase production, biofilm formation and to search for genes encoding for proteinases (SAP1, SAP3) and adhesion factors (ALS1 and ALS3). Another objective was to evaluate in vitro the antifungal activity of three commercial mouthwashes containing 0.12% chlorhexidine and 0.07% or 0.075% cetylpyridinium, against planktonic Candida sp. cultures and in biofilms. Saliva samples of 70 patients with dental prosthesis were collected, the yeasts were isolated on CHOMagar® Candida and identified by classical biochemical tests combined with molecular test (PCR) for confirmation of C. albicans. Yeasts of Candida genus were isolated from 32 samples (45.7%) and were identified as C. albicans (29), C. krusei (5), C. glabrata (4), C. tropicalis (3) and C. parapsilosis (2), with a total of 43 yeasts, including mono and mixed cultures. The genes studied were detected only in C. albicans: ALS2, ALS3 and SAP3 genes were detected in 86% of the isolates and SAP1 in 93%. The proteinase activity among the isolates of C. albicans was 72.4% and among the species of C. non-albicans it was 35.7%. Assay done with cultivation in 96-wells microplates and staining with XTT, showed the majority of Candida isolates and all the mixed cultures were able to form biofilms within 24h. The activity of the three mouthwashes towards the yeasts was < 1.25%, equivalent to a dilution of 1:80 of the formulation. The three mouthwashes tested were also active against mono or multispecies biofilms. In conclusion, it was shown C. albicans is the most prevalent species. The genes SAP1, SAP3, ALS2 and ALS3 are present in the majority of C. albicans isolates, which were also positive for proteinase and biofilm formation. There was more proteinase activity in C. albicans in comparison with C. non-albicans. The biofilms of Candida species grew better in mixed cultures than in monoculture. The three commercial mouthwashes formulations were effective against all the yeast isolates in planktonic growth and they also inhibited the majority of yeasts in biofilm. Future work is needed to completely elucidate the role of Candida species in biofilms of oral cavity. It is also interesting to propose studies to standardize sensitivity tests for mono and multi-species biofilms.

京都大学 / 0048 / 新制・課程博士 / 博士(生命科学) / 甲第18483号 / 生博第312号 / 新制||生||41(附属図書館) / 31361 / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 上村 匡, 教授 垣塚 彰, 教授 藤田 尚志 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

La technologie de reprogrammation de cellules somatiques en cellules souches pluripotentes induites (iPS) offre aujourd’hui l’opportunité de modéliser des maladies neurodégénératives et d’étudier des neurones de patients. Nous avons utilisé cette technologie pour générer deux modèles de maladies neurodégénératives : la mucopolysaccharidose de type IIIB (MPSIIIB) et la forme ALS2 de la sclérose latérale amyotrophique (SLA). Dans le modèle MPSIIIB, nous avons montré que les iPS et les neurones de patients présentaient des défauts caractéristiques de la pathologie telle que l’accumulation de vésicules de surcharge. Des altérations de l’appareil de Golgi dans ces cellules ont également été mises en évidence. Une analyse du transcriptome de précurseurs neuraux MPSIIIB a montré des modifications transcriptionnelles touchant notamment des gènes impliqués dans les interactions de la cellule avec la matrice extracellulaire. Ainsi, dans une seconde étude, des altérations de la migration et de l’orientation de cellules de souris mutantes MPSIIIB ou de patients ont été démontrées. Ces altérations pourraient être responsables des perturbations de la neurogénèse et de la neuritogénèse chez les enfants malades. Dans le modèle SLA/ALS2, nous avons montré que les neurones de patients présentaient des défauts incluant une diminution de la surface des endosomes et des anomalies de la croissance neuritique. Alors qu’il n’existait jusqu’alors aucun modèle cellulaire pertinent reproduisant cette maladie, ce modèle permettra à présent d’étudier les processus physiopathologiques impliqués dans la maladie. En conclusion, la génération de cellules iPS permet de modéliser des maladies neurodégénératives et d’étudier les processus physiopathologiques qui sont associés sur des neurones humains en culture. Ces modèles cellulaires pourraient permettre dans un avenir proche de réaliser des criblages de molécules à visée thérapeutique / Reprogramming technology of somatic cells in induced pluripotent stem cells (iPS) now offers the opportunity to model neurodegenerative diseases and to study patient’s neurons. We used this technology for generating two models of neurodegenerative diseases: the muccopolysaccharidosis type IIIB (MPSIIIB) and the ALS2 form of amyotrophic lateral sclerosis (ALS). In the MPSIIIB model, we have shown that iPS and neurons of patients had characteristic defects of the disease such as the accumulation of storage vesicles. Alterations of the Golgi apparatus in these cells were also highlighted. Transcriptome analysis of MPSIIIB neural precursors showed transcriptional changes involving particularly genes implicated in cell-extracellular matrix interactions. Thus, in a subsequent study, alterations of migration and orientation of MPSIIIB mutant mouse cells and MPSIIIB patients’ cells have been demonstrated. These alterations may be responsible for the disruption of neurogenesis and neuritogenesis in sick children. In the ALS2 model, we have shown that patients’ neurons had defects including decreased endosomes’ surface and abnormal neurite outgrowth. As there was previously no relevant cellular model reproducing the disease, this model will now allow the study of physiopathological processes involved in the disease. In conclusion, the generation of iPS cells allows to model neurodegenerative diseases and to study associated physiopathological processes on cultured human neurons. These cell models could allow in the near future the screening of molecules of potential therapeutical interest

La technologie de reprogrammation de cellules somatiques en cellules souches pluripotentes induites (iPS) offre aujourd'hui l'opportunité de modéliser des maladies neurodégénératives et d'étudier des neurones de patients. Nous avons utilisé cette technologie pour générer deux modèles de maladies neurodégénératives : la mucopolysaccharidose de type IIIB (MPSIIIB) et la forme ALS2 de la sclérose latérale amyotrophique (SLA). Dans le modèle MPSIIIB, nous avons montré que les iPS et les neurones de patients présentaient des défauts caractéristiques de la pathologie telle que l'accumulation de vésicules de surcharge. Des altérations de l'appareil de Golgi dans ces cellules ont également été mises en évidence. Une analyse du transcriptome de précurseurs neuraux MPSIIIB a montré des modifications transcriptionnelles touchant notamment des gènes impliqués dans les interactions de la cellule avec la matrice extracellulaire. Ainsi, dans une seconde étude, des altérations de la migration et de l'orientation de cellules de souris mutantes MPSIIIB ou de patients ont été démontrées. Ces altérations pourraient être responsables des perturbations de la neurogénèse et de la neuritogénèse chez les enfants malades. Dans le modèle SLA/ALS2, nous avons montré que les neurones de patients présentaient des défauts incluant une diminution de la surface des endosomes et des anomalies de la croissance neuritique. Alors qu'il n'existait jusqu'alors aucun modèle cellulaire pertinent reproduisant cette maladie, ce modèle permettra à présent d'étudier les processus physiopathologiques impliqués dans la maladie. En conclusion, la génération de cellules iPS permet de modéliser des maladies neurodégénératives et d'étudier les processus physiopathologiques qui sont associés sur des neurones humains en culture. Ces modèles cellulaires pourraient permettre dans un avenir proche de réaliser des criblages de molécules à visée thérapeutique