Mendelian randomization analysis of psoriasis and psoriatic arthritis associated with risks of ulcerative colitis

Multi-omics analysis of outer membrane vesicles from P. goldsteinii in a psoriasis mouse model

AIMS

Psoriasis is a chronic skin inflammation with no complete cure. Parabacteroides goldsteinii (P. goldsteinii), a probiotic, alleviates inflammation by modulating gut microbiota. Its outer membrane vesicles (PG-OMVs) deliver microbial molecules to influence host-microbiota interactions. However, their role in psoriasis remains unclear. This study explores the effects and mechanisms of PG-OMVs in psoriasis.

MATERIALS AND METHODS

PG-OMVs were isolated from P. goldsteinii using high-pressure tangential flow ultrafiltration combined with size exclusion chromatography, and characterized by transmission electron microscopy and nano-flow cytometry. Subsequently, Lipidomic and proteomic analysis was performed to investigate the composition of PG-OMVs. A psoriasis-like mouse model was established using imiquimod to evaluate their therapeutic effects. Furthermore, transcriptomic analysis, in situ sequencing, and 16S rRNA sequencing were applied to skin and fecal samples to explore underlying mechanisms. An in vitro model using LPS-stimulated HaCaT keratinocytes was also employed to assess the cytotoxicity and anti-inflammatory activity of PG-OMVs.

KEY FINDINGS

PG-OMVs have an average diameter of approximately 84.9 nm and a uniformly disc-like morphology. Lipidomic and proteomic revealed diverse lipid species and proteins potentially involved in regulating metabolic dysfunction. In the imiquimod-induced mouse model, PG-OMVs alleviated skin lesions and histopathological changes. Mechanistic studies showed that PG-OMVs modulate mTOR, TNF, and IL-17 pathways, regulate inflammatory and proliferative genes (e.g., AKT1, mTOR, FOS, FOSB), and restore gut microbial balance. In vitro, PG-OMVs significantly suppressed pro-inflammatory cytokines.

SIGNIFICANCE

This study demonstrates that PG-OMVs ameliorate psoriasis by regulating inflammatory pathways and the gut microbiota, offering a promising therapeutic strategy.

Role of miRNAs in the pathogenesis of psoriasis and psoriatic arthritis: a genome-wide Mendelian randomization study

BACKGROUND

MicroRNAs (miRNAs) are critical in the onset and treatment of skin diseases, but the miRNAs causally associated with psoriasis (PSO) and psoriatic arthritis (PsA) remain unclear. This study aims to identify miRNAs with causal associations with PSO and PsA.

METHODS

Five Mendelian randomization (MR) methods were employed, using miRNA expression quantitative trait loci (mirQTL) data as exposure variables and PSO and PsA as outcome variables. This approach was used to uncover the causal links of miRNAs with both PSO and PsA, with robust sensitivity analyses ensuring the stability of our findings. Finally, miRNet and enrichment analyses were used to predict target genes of the causal miRNAs and their potential biological roles.

RESULTS

Our robust findings indicated that miR-27b-3p, miR-204-5p, and miR-6891-3p were notably associated with an enhanced risk of PSO. Additionally, miR-6891-3p was greatly associated with an enhanced risk of PsA. Conversely, miR-29c-3p, miR-181a-3p, miR-181a-5p, miR-181b-5p, and miR-199a-3p were substantially associated with a reduced risk of both PSO and PsA. Enrichment analyses revealed that the target genes of these causal miRNAs were markedly enriched in biological pathways such as apoptosis, Wnt, and PI3K-AKT signaling.

CONCLUSION

This study identifies eight miRNAs causally associated with PSO and five miRNAs associated with PsA, with no observed heterogeneity or pleiotropy. These findings offer potential biomarkers for the diagnosis and treatment of PSO and PsA. Key Points • We conducted the first genome-wide MR study to explore the causal relationships between miRNAs and PSO and PsA. • The study found stable and reliable causal effects of 8 miRNAs on PSO and 5 miRNAs on PsA. • These miRNAs provide important insights into elucidating the pathophysiological mechanisms of PSO and PsA and developing new therapeutic approaches.

Association of partial infections with the risk of psoriasis: A two-sample Mendelian randomization study

BACKGROUND

As a common chronic recurrent inflammatory skin disease, psoriasis is characterized by erythema and scaly skin lesions, with infection as an integral part of the pathogenesis of many diseases. Many previous cases reported the impact of psoriasis on infection. However, the existing research fails to completely clarify the infection factors associated with the potential of these diseases and causality.

MATERIALS AND METHODS

Thirteen kinds of pathogens and their immune responses and psoriasis in the phenotype of 46 species of SNPs data were respectively obtained from the GWAS catalog database and the UK biobank database. With the help of R software, three methods of inverse variance weighted (IVW), weighted median (WME), and MR-Egger regression were used to analyze the causality of the dataset.

RESULTS

According to the results of IVW analysis, there is a causal relationship between anti-Epstein Barr virus antibody and psoriasis (OR: 1.003, 95% CI: 1.001∼1.006, P = 0.046) with a positive correlation.

CONCLUSION

Based on the results of MR analysis, there is a causal relationship between psoriasis and EBV infection, which indicates that EBV infection can increase the risk or severity of psoriasis. Therefore, in clinical scenarios, patients afflicted with psoriasis should be prevented from contracting the infection and recurrence of EBV as well as symptoms of psoriasis. The underlying immunological mechanism also provides a new perspective for experimental research.