Expression of B lymphocyte-induced maturation protein 1 (Blimp-1) in keratinocyte and cytokine signalling drives human Th17 response in psoriasis

Transcriptional factor B lymphocyte-induced maturation protein 1 (Blimp-1) is pivotally implicated in T helper 17 (Th17) cell differentiation. This study investigated expression of the Blimp-1 protein, positive regulatory domain 1 (PRDM1), and cytokine genes in psoriasis (PsO). Affected (AS-PsO) and non-affected skin (nAS-PsO) samples were used to assess gene and protein expressions by reverse transcription-quantitative PCR (RT-qPCR), and immunostaining and confocal microscopy, respectively; the normalised public transcriptomic data permitted differential gene expression analyses. On RT-qPCR, PRDM1 and IL17A transcripts showed higher expression in AS-PsO than in nAS-PsO (n = 34) (p < 0.001; p < 0.0001, respectively). Confocal microscopy showed Blimp-1 protein expression in epidermal layer keratinocytes in AS-PsO, but not in nAS-PsO. Bioinformatic analysis of the transcriptomic dataset GSE13355 corroborated the increased PRDM1, signal transducer and activator of transcription 3 (STAT3), IL12B, TNF, IL17A, IL6, IL1B, IL22, and IL10 gene expression in AS-PsO, when compared to normal skin and nAS-PsO (p < 0.001). PRDM1 expression correlated positively (p < 0.0001) with that of IL17A (r = 0.7), IL1B (r = 0.67), IL12B (r = 0.6), IL6 (r = 0.59), IL22 (r = 0.53), IL23A (r = 0.47), IL21 (r = 0.47), IL27 (r = 0.34), IL23R (r = 0.32), S100 calcium binding protein A9 (r = 0.63), and lipocalin 2 (r = 0.50), and negatively with that of TGFB1 (r = - 0.28) and RORC (r = - 0.60). Blimp-1 may be critical in the pathogenesis of PsO dysregulation involving the Th17 inflammatory pathway. This knowledge may accelerate the development of new treatments.

Automated summary

This study found that the transcriptional factor Blimp-1 is implicated in the pathogenesis of psoriasis (PsO) by regulating the expression of genes involved in the Th17 inflammatory pathway. The expression of PRDM1 and IL17A was increased in PsO, and PRDM1 correlated positively with the expression of several cytokines. This knowledge may contribute to the development of new treatments for PsO.