AQP9 and psoriasis: Based on the above findings, we hypothesized that AQP9, as a water glycerol channel protein, might participate in the comorbidity mechanism of IBD and psoriasis by regulating the water glycerol balance of intestinal and epidermal epithelial cells, and ssGSEA showed that AQP9 may play a role in regulating the NF-kappaB signaling pathway in both diseases.