Increased IL17A, IFNG, and FOXP3 Transcripts in Moderate-Severe Psoriasis: A Major Influence Exerted by IL17A in Disease Severity

LY294002 ameliorates psoriatic skin inflammation in mice via blocking the Notch1/Hes1-PTEN/AKT/IL-17A feedback loop

(IL)-17A, the effective factor of Th17 cells, acts an important pathological role in the pathogenesis of psoriasis. Notch1/hairy and split 1 (Hes1) and PI3K/AKT signaling pathways are interpenetrated and involved in Th17 cell differentiation and IL-17A production. In this present study, we used imiquimod (IMQ)-induced mouse psoriatic skin inflammation to explore the possible mechanism of Notch1/Hes1-PTEN/AKT/IL-17A feedback loop in psoriasis by employing AKT inhibitor LY294002 as an intervention with the methods of flow cytometry analysis, reverse transcription-quantitative polymerase chain reaction, western blot, co-immunoprecipitation, and immunofluorescence. First, LY294002 inhibition can obviously alleviate the mouse psoriatic skin inflammation both in skin structural and histopathological characteristics, which is similar to the changes found in IL-17A antibody-treated mice. Additionally, the interaction between Notch1 intracellular domain (NICD1) and nuclear factor kappa B (NF-κB) activator 1 (Act1) was demonstrated. LY294002 interruption resulted in consistent changes in expression levels of key signaling molecules both in Notch1/Hes1 and PI3K/AKT signaling pathways in a time-dependent manner. Moreover, chloroquine (CQ) can partly reverse the inhibitory effects of LY294002 on the Notch1/Hes1-PTEN/AKT/IL-17A feedback loop by affecting Notch1 ubiquitination and lysosomal degradation. The present study showed that LY294002 can exert the inhibitory effect on Notch1/Hes1-PTEN/AKT/IL-17A feedback loop to regulate Th17 cell differentiation and IL-17A function in the process of psoriasis, which provides a new possible therapeutic strategy for psoriasis.

Transcriptomic Profiling of Peripheral Edge of Lesions to Elucidate the Pathogenesis of Psoriasis Vulgaris

Elucidating transcriptome in the peripheral edge of the lesional (PE) skin could provide a better understanding of the molecules or signalings that intensify inflammation in the PE skin. Full-thickness biopsies of PE skin and uninvolved (UN) skin were obtained from psoriasis patients for RNA-seq. Several potential differentially expressed genes (DEGs) in the PE skin compared to those in the UN skin were identified. These DEGs enhanced functions such as angiogenesis, growth of epithelial tissue, chemotaxis and homing of cells, growth of connective tissues, and degranulation of myeloid cells beneath the PE skin. Moreover, the canonical pathways of IL-17A, IL-6, and IL-22 signaling were enriched by the DEGs. Finally, we proposed that inflammation in the PE skin might be driven by the IL-36/TLR9 axis or IL-6/Th17 axis and potentiated by IL-36α, IL-36γ, IL-17C, IL-8, S100A7, S100A8, S100A9, S100A15, SERPINB4, and hBD-2. Along with IL-36α, IL-17C, and IκBζ, ROCK2 could be an equally important factor in the pathogenesis of psoriasis, which may involve self-sustaining circuits between innate and adaptive immune responses via regulation of IL-36α and IL-36γ expression. Our finding provides new insight into signaling pathways in PE skin, which could lead to the discovery of new psoriasis targets.

Levels of the interleukins 17A, 22, and 23 and the S100 protein family in the gingival crevicular fluid of psoriatic patients with or without periodontitis

BACKGROUND

Psoriasis and periodontitis are immunologically mediated chronic inflammatory diseases. Epidemiologic evidence has linked both; however, the change of markers in gingival crevicular fluid has been poorly evaluated.

OBJECTIVE

To evaluate the levels of IL-17A, IL-22, IL-23, S100A7, S100A8, and S100A9 in gingival crevicular fluid of psoriatic and healthy subjects with and without periodontitis and their relations to psoriasis severity.

METHODS

Cross-sectional study. Sample comprised the following groups: healthy controls without periodontitis or with mild periodontitis (n=21), healthy controls with moderate or severe periodontitis (n=18), individuals with psoriasis without or mild periodontitis (n=11), and individuals with psoriasis and moderate or severe periodontitis (n=32). Levels of IL-17A, IL-22, IL-23, S100A8, and S100A9 were determined by multiplex assay and S100A7 was measured by ELISA.

RESULTS

No inter-group differences in the levels of IL-17A, IL-22, IL-23, and S100A7 were found. S100A8 levels were higher in psoriatic patients than controls (p<0.05). S100A8 was positively correlated with psoriasis severity in the group with psoriasis (p<0.05). S100A9 exceeded the detection limits.

STUDY LIMITATIONS

This pilot study presents a small sample size.

CONCLUSIONS

The concentrations of S100A8 were highest in psoriatic patients regardless of periodontal health/status. S100A8 was associated with the severity of psoriasis. The concentrations of interleukins and S100A7 were similar in psoriatic patients with or without periodontitis vs. healthy controls.