Endoplasmic reticulum stress links psoriasis vulgaris with keratinocyte inflammation

Introduction
Endoplasmic reticulum stress (ERS) has been implicated in the pathogenesis of various inflammatory diseases. However, the role of ERS in psoriasis is still unclear.

Aim
To examine ERS in psoriasis keratinocytes and to assess the association of ERS with skin inflammation response.

Material and methods
We investigated ERS in keratinocytes of normal skin, lesional and perilesional psoriasis vulgaris (PV) skin tissues using transmission electron microscope (TEM) examination, Western blot and immunostaining analysis.

Results
By TEM examination, we found that endoplasmic reticulum (ER) in psoriatic keratinocytes was ultrastructurally abnormal, with changes in ER morphology and the ER expansion. Using Western blot and immunostaining analysis, we showed that the expression of ERS-associated proteins, such as BiP, CHOP and XBP1, was enhanced in PV epidermis compared to the healthy skin. Moreover, abundant TNF-a protein was correlated to the increased BiP, CHOP and XBP1 expression in PV epidermis.

Conclusions
Our findings demonstrate that PV keratinocytes have an increased ERS, which may contribute to the pathogenesis of PV.