The signature of the gut microbiota associated with psoriatic arthritis revealed by metagenomics.

Background: Gut microbiota is involved in the development of psoriatic arthritis (PsA), but until now, there has been a lack of understanding of the PsA host-bacteria interaction.

Objectives: To reveal the labels of gut microbiota in PsA patients and the species and functions related to disease activity.

Design: Observational research (cross-sectional) with an exploratory nature.

Methods: Metagenomics sequencing was used to analyze stool samples from 20 treatment-naïve PsA patients and 10 age-matched healthy individuals. All samples were qualified for subsequent analysis.

Results: Compared with the healthy group, α-diversity was reduced in the PsA group, and β-diversity could distinguish the two groups. Two bacteria with high abundance and correlation with PsA disease activity were identified, Bacteroides sp. 3_1_19 and Blautia AF 14-40. In different functions, K07114 (calcium-activated chloride channel (CaCC) homolog) showed a positive correlation with PsA disease activity (disease activity in psoriatic arthritis, DAPSA) and Tet32 (an antibiotic-resistant gene), and carbohydrate-binding module family 50 was negatively correlated with erythrocyte sedimentation rate. A bacterial co-expression network associated with DAPSA was constructed. The network was centered on the bacteria in the Bacteroides genus, which formed a closely related network and were positively correlated with DAPSA. As another core of the network, K07114 was closely related to multiple bacteria in the Bacteroides genus and is also positively correlated with disease activity.

Conclusion: The network composed of Bacteroides is associated with PsA disease activity, and its therapeutic value needs to be further explored. CaCCs may be a key channel for the interaction between Bacteroides and PsA-host.