Impacto de consorcios microbianos productores de metabolitos neuroprotectores en un modelo de neurodegeneración animal
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2024
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El microbioma intestinal humano representa un ecosistema microbiano diverso y complejo que cumple importantes funciones que inciden sobre la salud del huésped. En los últimos años se ha evidenciado su influencia sobre enfermedades del sistema nervioso donde la comunicación bidireccional definida como eje microbioma-intestino-cerebro desempeña un rol fundamental. En esta comunicación la producción de neurometabolitos por el microbioma intestinal ha mostrado ser clave en la modulación del sistema nervioso. En particular GABA, el principal neurotransmisor inhibitorio del sistema nervioso central (SNC), ha exhibido un rol en la modulación de la depresión, ansiedad y en la neurodegeneración. Asimismo, butirato, uno de los ácidos grasos de cadena corta que cumple funciones fisiológicas importantes en el huésped, ha mostrado mantener la barrera hematoencefálica, regular procesos neuroinflamatorios y tener un efecto neuroprotector.El estudio del impacto del microbioma intestinal sobre enfermedades del sistema nervioso se ha llevado a cabo mediante el uso de sistemas in vitro y modelos animales donde se evalúa el tratamiento del efecto de una o más cepas bacterianas sobre una condición determinada. Sin embargo, en los últimos años, la aplicación de ingeniería de consorcios microbianos ha despertado creciente interés para el diseño racional y controlado de comunidades microbianas con funciones específicas. Este enfoque permite predecir de manera robusta la composición e interacciones microbianas claves. A pesar de las ventajas que ofrecen estos métodos, actualmente su uso no ha sido descrito en el estudio del impacto del microbioma sobre la neurodegeneración.El objetivo general de esta propuesta fue estudiar el impacto de consorcios microbianos optimizados para la producción de GABA y butirato sobre la neurodegeneración en un modelo animal. En línea con esto los objetivos específicos fueron: 1) Diseñar consorcios microbianos de bacterias intestinales optimizados para la producción de GABA y butirato; 2) Caracterizar, validar y producir los consorcios microbianos productores de GABA y butirato que se diseñaron in silico a escala de laboratorio en un biorreactor batch; 3) Evaluar la neurodegeneración en un modelo animal tras el tratamiento con los consorcios microbianos. Para lograr estos objetivos en una primera etapa se realizaron simulaciones de la comunidad microbiana con modelos a escala genómica (GSMMs) de las bacterias productoras de GABA, butirato y bacterias residentes representativas del microbioma intestinal utilizando el algoritmo de diseño de comunidades microbianas SteadyCom. Este algoritmo se implementó en el paquete COBRA de MATLAB. Posteriormente, los consorcios bacterianos optimizados in silico se evaluaron en un biorreactor batch donde se obtuvo información sobre la abundancia de las bacterias, producción de neurometabolitos y consumo de sustrato durante la fermentación. Finalmente, se estudió el efecto de uno de los consorcios sobre la neurodegeneración en un modelo de Parkinson en Drosophila melanogaster, donde se evaluó la capacidad locomotora, sobrevida, la integridad neuronal y el perfil de metabolitos sobre-expresados tras el tratamiento con el consorcios bacterianos.Los resultados indicaron que el tratamiento con el consorcio bacteriano no tiene un efecto negativo en la sobrevivencia de D. melanogaster aumentando inclusive su sobrevida. Produce un rescate fenotípico locomotor en moscas con la enfermedad de 10 y 25 días de edad. Restaura el perfil de metabolitos alterados asociados al balance energético, redox, metabolismo de aminoácidos y neurotransmisores, así como también reduce el nivel de biomarcadores asociados la enfermedad. Por último, el consorcio modula el microbioma intestinal en el modelo de Parkinson, lo que podría ser un mecanismo para reducir la patología de la enfermedad. En síntesis la presencia del consorcio bacteriano produce un cambio en la composición del microbiona intestinal de Drosophila Parkinsoniana, donde la producción bacteriana del neurotransmisor GABA y otros intermediaros metabólicos, su degradación en moléculas benéficas y la interacción con otros miembros del microbioma intestinal podría favorecer el balance del microbioma, reducir las alteraciones metabólicas de la enfermedad, mejorando la comunicación del eje microbioma-intestino-cerebro, reduciendo así los síntomas locomotores asociados a la enfermedad y logrando tener un efecto neuroprotector en un modelo de Parkinson en Drosophila melanogaster.
The human gut microbiome represents a diverse and complex microbial ecosystem thatperforms essential functions that affect host health. In recent years, its influence on nervoussystem diseases has been evidenced, where a bidirectional communication, defined as themicrobiome-gut-brain axis, has been described. In this context the production ofneurometabolites by gut microbiome bacteria has been shown to be important for themodulation of nervous system activity. In particular, GABA, the main inhibitoryneurotransmitter of the central nervous system (CNS), which plays a role in depression,anxiety, and neurodegeneration, and butyrate, a short-chain fatty acid with functions such asmaintenance of the blood-brain barrier, neuroinflammatory processes, and neuroprotectiveeffect. The impact of the intestinal microbiome on nervous system diseases has been studiedusing in vitro systems and animal models where the treatment effect of one or more bacterialstrains on a given condition is evaluated. In recent years, microbial consortia engineeringhas attracted increasing interest because it allows the rational and controlled design ofmicrobial communities with specific functions. This approach permits robust prediction of microbial composition and their interactions. Despite the advantages offered by this method,its use has not been applied to the study of the role of the microbiome in neurodegeneration.The general objective of this proposal was to study the impact of microbial consortiaoptimized for GABA and butyrate production in neurodegeneration in an animal model. Inline with this, the specific objectives were: 1) To design in silico microbial consortia ofintestinal bacteria optimized for GABA and butyrate production; 2) To characterize,validate, and produce the GABA and butyrate-producing microbial consortia that weredesigned in silico at laboratory scale in a batch bioreactor; 3) To evaluate neurodegenerationin an animal model after treatment with the microbial consortia. For this, simulations of themicrobial community were performed with genomic scale models (GSMMs) of GABAproducing bacteria, butyrate-producing bacteria, and commensal bacteria representative ofthe gut microbiome using the SteadyCom microbial community design algorithm. Thisalgorithm was implemented in the MATLAB package COBRA. Subsequently, the in silicooptimized bacterial consortia were evaluated in a batch bioreactor where information onbacterial abundance, neurometabolite production, and substrate consumption duringfermentation was obtained. Finally, the effect of the most effective consortia was used tostudy it in a Parkinson model in Drosophila melanogaster, where locomotor capacity,survival, neuronal integrity, and the profile of over-expressed metabolites were evaluatedafter treatment with the bacterial consortium.The results indicated that treatment with the bacterial consortium has no deleterious impacton control D. melanogaster survival, but more critically, it protects the PD flies' which donot develop a locomotor phenotype at 10 and even at 25 days of age. Also, it restores theprofile of altered metabolites associated with energy balance, redox, amino acid, and neurotransmitter metabolism and reduces the level of biomarkers associated with the disease.Therefore, the consortium fed to animals mutant for -synuclein, an accepted Parkinson’smodel, is able to colonize the intestinal microbiome and could be a mechanism to reduce thesymptoms of the disease. In summary, the consortium changes the gut microbiomecomposition of PD Drosophila, where the bacterial production of the neurotransmitterGABA and other metabolic intermediates, its degradation into beneficial molecules and theinteraction with other members of the gut microbiome could favor the microbiome balance,reduce PD metabolic alterations, improving the communication of the microbiome-gut-brainaxis, thus reducing the locomotor symptoms associated with the disease and achieving aneuroprotective effect in a model of Parkinson's disease in Drosophila melanogaster.
The human gut microbiome represents a diverse and complex microbial ecosystem thatperforms essential functions that affect host health. In recent years, its influence on nervoussystem diseases has been evidenced, where a bidirectional communication, defined as themicrobiome-gut-brain axis, has been described. In this context the production ofneurometabolites by gut microbiome bacteria has been shown to be important for themodulation of nervous system activity. In particular, GABA, the main inhibitoryneurotransmitter of the central nervous system (CNS), which plays a role in depression,anxiety, and neurodegeneration, and butyrate, a short-chain fatty acid with functions such asmaintenance of the blood-brain barrier, neuroinflammatory processes, and neuroprotectiveeffect. The impact of the intestinal microbiome on nervous system diseases has been studiedusing in vitro systems and animal models where the treatment effect of one or more bacterialstrains on a given condition is evaluated. In recent years, microbial consortia engineeringhas attracted increasing interest because it allows the rational and controlled design ofmicrobial communities with specific functions. This approach permits robust prediction of microbial composition and their interactions. Despite the advantages offered by this method,its use has not been applied to the study of the role of the microbiome in neurodegeneration.The general objective of this proposal was to study the impact of microbial consortiaoptimized for GABA and butyrate production in neurodegeneration in an animal model. Inline with this, the specific objectives were: 1) To design in silico microbial consortia ofintestinal bacteria optimized for GABA and butyrate production; 2) To characterize,validate, and produce the GABA and butyrate-producing microbial consortia that weredesigned in silico at laboratory scale in a batch bioreactor; 3) To evaluate neurodegenerationin an animal model after treatment with the microbial consortia. For this, simulations of themicrobial community were performed with genomic scale models (GSMMs) of GABAproducing bacteria, butyrate-producing bacteria, and commensal bacteria representative ofthe gut microbiome using the SteadyCom microbial community design algorithm. Thisalgorithm was implemented in the MATLAB package COBRA. Subsequently, the in silicooptimized bacterial consortia were evaluated in a batch bioreactor where information onbacterial abundance, neurometabolite production, and substrate consumption duringfermentation was obtained. Finally, the effect of the most effective consortia was used tostudy it in a Parkinson model in Drosophila melanogaster, where locomotor capacity,survival, neuronal integrity, and the profile of over-expressed metabolites were evaluatedafter treatment with the bacterial consortium.The results indicated that treatment with the bacterial consortium has no deleterious impacton control D. melanogaster survival, but more critically, it protects the PD flies' which donot develop a locomotor phenotype at 10 and even at 25 days of age. Also, it restores theprofile of altered metabolites associated with energy balance, redox, amino acid, and neurotransmitter metabolism and reduces the level of biomarkers associated with the disease.Therefore, the consortium fed to animals mutant for -synuclein, an accepted Parkinson’smodel, is able to colonize the intestinal microbiome and could be a mechanism to reduce thesymptoms of the disease. In summary, the consortium changes the gut microbiomecomposition of PD Drosophila, where the bacterial production of the neurotransmitterGABA and other metabolic intermediates, its degradation into beneficial molecules and theinteraction with other members of the gut microbiome could favor the microbiome balance,reduce PD metabolic alterations, improving the communication of the microbiome-gut-brainaxis, thus reducing the locomotor symptoms associated with the disease and achieving aneuroprotective effect in a model of Parkinson's disease in Drosophila melanogaster.
Description
Tesis (Doctor in Engineering Sciences)--Pontificia Universidad Católica de Chile, 2024.
TESIS EMBARGADA HASTA EL 30 DE ABRIL DE 2026
TESIS EMBARGADA HASTA EL 30 DE ABRIL DE 2026
Keywords
Ingeniería de consorcios microbianos, Eje microbioma-intestino- cerebro, Enfermedad de Parkinson, GABA, Drosophila melanogaster, Microbial consortium engineering, Gut-brain axis, Parkinson's disease, GABA, Drosophila melanogaster