Modulação do metabolismo e da resposta inflamatória na sepse
Data
2022-06-22
Autores
Ferreira, Bianca Rodrigues Lima [UNIFESP]
Orientadores
Salomão, Reinaldo [UNIFESP]
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A Sepse é causada por uma resposta desregulada do hospedeiro à infecção e é uma das principais causas de morte em UTI. Leucócitos de pacientes com sepse apresentam simultaneamente tanto respostas pró-inflamatórias quanto anti-inflamatórias, apresentando um fenótipo de tolerância à endotoxina. Além disso, o metabolismo celular pode influenciar a resposta imune na sepse. Entretanto, diversos aspectos da imunopatologia da sepse não são completamente entendidos. Esse estudo teve como objetivo investigar as adaptações metabólicas e imunes em leucócitos de pacientes sépticos. Utilizando um PCR Array para avaliar a expressão de genes relacionados ao regulador metabólico HIF (fator de transcrição induzido por hipóxia) -1α em células mononucleares de pacientes sépticos, foi observada uma regulação distinta dessa via entre sobreviventes e não sobreviventes, com uma maior expressão naqueles que não sobreviveram. Integrando informações de transcriptoma e proteoma para gerar redes de interação proteína-proteína (PPIN), foram identificados módulos relacionados a alterações metabólicas, comprometimento de processos de transcrição e tradução, e uma inflamação aumentada nos leucócitos de pacientes sépticos, relacionada a neutrófilos de baixa densidade. Foi também observado uma regulação positiva do metabolismo da glicose no proteoma de células mononucleares desses pacientes, e num modelo in vitro de tolerância à endotoxina, a glicose foi necessária para sustentar produção de citocinas e fagocitose tanto em células tolerantes como nos controles. Adicionalmente, com uma análise da produção de citocinas em resposta a estímulo ex vivo, foi observado que pacientes com sepse por COVID-19 não apresentaram um perfil de tolerância à endotoxina. Esses resultados ajudam a compreender diferentes mecanismos que levam à resposta desregulada na sepse e destacam a complexidade desse processo.
Sepsis is caused by a dysregulated host response to infection and is a major cause of death in ICUs. Leukocytes from patients with sepsis present simultaneous pro-inflammatory and anti-inflammatory responses, displaying an endotoxin-tolerance phenotype. Additionally, cellular metabolism may influence the immune response in sepsis. However, many aspects of sepsis immunopathology are not fully understood. This study aimed to investigate metabolic and immune adaptations in septic patient’s leukocytes. Using a PCR array to evaluate the expression of genes related to the metabolic regulator hypoxia inducible factor (HIF) - 1α in septic patient’s mononuclear cells, we observed a distinct regulation of this pathway between survivors and non-survivors, with an increased expression in those who did not survive. By integrating transcriptome and proteome information to generate protein-protein interaction networks (PPIN), we identified modules related to metabolic alterations, impairment of transcriptional and translational processes and an increased inflammation in patients’ leukocytes, related to low-density neutrophils. We also observed upregulated glucose metabolism in the proteome of patients’ mononuclear cells, and in an in vitro endotoxin-tolerance model, glucose was necessary to support cytokine production and phagocytosis in both control and tolerant cells. Additionally, by analyzing cytokine production upon ex vivo stimulation, we observed that patients with COVID-19 sepsis did not present an endotoxin-tolerance profile. These results contribute to understand distinct mechanisms leading to the dysregulated response in sepsis and highlight the complexity of this process.
Sepsis is caused by a dysregulated host response to infection and is a major cause of death in ICUs. Leukocytes from patients with sepsis present simultaneous pro-inflammatory and anti-inflammatory responses, displaying an endotoxin-tolerance phenotype. Additionally, cellular metabolism may influence the immune response in sepsis. However, many aspects of sepsis immunopathology are not fully understood. This study aimed to investigate metabolic and immune adaptations in septic patient’s leukocytes. Using a PCR array to evaluate the expression of genes related to the metabolic regulator hypoxia inducible factor (HIF) - 1α in septic patient’s mononuclear cells, we observed a distinct regulation of this pathway between survivors and non-survivors, with an increased expression in those who did not survive. By integrating transcriptome and proteome information to generate protein-protein interaction networks (PPIN), we identified modules related to metabolic alterations, impairment of transcriptional and translational processes and an increased inflammation in patients’ leukocytes, related to low-density neutrophils. We also observed upregulated glucose metabolism in the proteome of patients’ mononuclear cells, and in an in vitro endotoxin-tolerance model, glucose was necessary to support cytokine production and phagocytosis in both control and tolerant cells. Additionally, by analyzing cytokine production upon ex vivo stimulation, we observed that patients with COVID-19 sepsis did not present an endotoxin-tolerance profile. These results contribute to understand distinct mechanisms leading to the dysregulated response in sepsis and highlight the complexity of this process.