Imiquimod-induced psoriasis-like inflammation model in calcium-differentiated human keratinocytes mimics psoriasis-associated biomolecules and signaling pathways

Dysregulation of keratinocytes and immune response are remarkable phenomena that trigger inflammation in the psoriasis pathology. In vitro models for elucidating psoriasis pathogenesis and treatment provide the potential to mimic enhanced systems that more accurately represent the disease phenotype and immunopathogenesis. The aim of this study was to investigate the morphological, molecular and biochemical changes of cell–cell interactions in CaCl₂-differentiated HaCaT cells under imiquimod (IMQ)-induced inflammatory conditions. To establish this model, HaCaT cells were differentiated with CaCl₂ and then stimulated with IMQ to induce psoriatic inflammation. Morphological analyses were evaluated on inverted microscope images and HE-stained cells under light microscopy. Cell proliferation was analyzed by the MTT assay and confirmed with the PCNA biomarker. Psoriasis-associated biomarkers were evaluated by immunofluorescence staining. Cytokine levels were measured by ELISA, and the expressions of Toll-like receptors (TLRs), NLRP3 inflammasome, angiogenic, hypoxia, and TGF-β/Smads genes were assessed by qRT-PCR. The results revealed that IMQ-induced HaCaT cells exhibited morphology and organization mimicking psoriatic keratinocytes. The expressions of CK17, PCNA, actin, prohibitin and inflammatory cytokines were significantly increased in the IMQ group. Furthermore, significant changes were detected in the gene expression levels of inflammation-related TLRs, NLRP3 inflammasome complex, angiogenic, hypoxia, and TGF-β/Smads. This model effectively mimics psoriatic inflammatory responses in HaCaT cells and may serve as a cost-effective tool to evaluate the anti-psoriatic potential of new drug candidates.