The Pathogenesis of Psoriasis Vulgaris Mediated by Gut Microbiota-Host Co-Metabolism Regulating Tryptophan Metabolic Pathway

Abstract

Background: Psoriasis vulgaris (PV) is one of the most common chronic inflammatory skin diseases, but its exact etiology and pathological mechanism are not fully understood. The regulation of tryptophan metabolism by gut microbiota-host co-metabolism has been confirmed to significantly affect the pathogenesis of various chronic inflammatory and autoimmune diseases. Tryptophan and its main metabolites are partly involved in the pathogenesis and progression of psoriasis, but its specific regulatory mechanism has not yet been clarified. The purpose of this study is to explore the changes in the intestinal flora and its metabolic characteristics in PV patients. Methods: 16S rRNA sequencing combined with metabolomics was used to explore changes in gut microbiota and its metabolic characteristics. Alpha, Beta diversity and LEfSe (Linear Discriminant Analysis Effect Size) analyses were used to analyze the changes in the intestinal flora and to screen biomarkers. PCA (Principal Component Analysis) and OPLS-DA (Orthogonal Partial Least Squares-Discriminant Analysis) methods were used to analyze the differences in metabolite composition. PICRUS (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) software was used to predict metabolic function. Results: The result revealed differences in the tract microbiota composition between normal and psoriasis patients, suggesting that microbial populations may mediate the development of psoriasis. Fecal metabolite profiles revealed distinct metabolites associated with the psoriasis samples group (PSG). These products of metabolism primarily participated in metabolic pathways including amino acid biosynthesis, carbohydrate degradation and glycolysis. There is a positive/negative correlation between these gut microbes and metabolites. Conclusions: The results suggest that the gut microbiota and its metabolites may play a crucial role in the development of PSG, which may provide a potential biomarker for the treatment of PSG.