Targeting EGR1 Attenuates CCL2 Expression in Inflammatory Keratinocytes and Allergic Skin Inflammation

Abstract

Early growth response 1 (EGR1) is a zinc-finger transcription factor involved in inflammatory gene regulation, but the extent to which pharmacological inhibition of EGR1 DNA-binding activity influences inflammatory transcriptional responses in keratinocytes remains incompletely understood. Here, we explored the transcriptional effects of pharmacological EGR1 inhibition in tumor necrosis factor-α (TNFα)-stimulated HaCaT keratinocytes. RNA sequencing was employed as an exploratory, hypothesis-generating screen using three structurally related EGR1 inhibitors (IT21, IT23, and IT25) to identify candidate genes showing concordant expression patterns across the three pharmacological perturbations. This exploratory analysis suggested broader changes in inflammation-associated transcriptional programs and identified several leukocyte-recruiting chemokines among the candidate genes. CCL2 was selected as a representative candidate for independent biological and mechanistic validation. IT25 treatment and EGR1 knockdown attenuated TNFα-induced CCL2 expression, while promoter–reporter analysis, EGR1-binding site mutagenesis, EGR1 overexpression, and chromatin immunoprecipitation supported EGR1-dependent transcriptional regulation of CCL2 in keratinocytes. Furthermore, topical IT25 treatment attenuated house dust mite-induced atopic dermatitis-like skin inflammation and was associated with reduced epidermal CCL2 expression and inflammatory cell infiltration in vivo. Collectively, these findings establish EGR1-dependent regulation of CCL2 in inflammatory keratinocytes and support further investigation of EGR1 DNA-binding activity as a pharmacological target in cutaneous inflammation.