Psoriasis is a common inflammatory skin disease with complex etiology and chronic progression. To provide novel insights into the regulatory molecular mechanisms of the disease, we performed RNA sequencing analysis of 14 pairs of skin samples collected from patients with psoriasis. Subsequent pathway analysis and extraction of the transcriptional regulators governing psoriasis-associated pathways was executed using a combination of the MetaCore Interactome enrichment tool and the cisExpress algorithm, followed by comparison to a set of previously described psoriasis response elements. A comparative approach allowed us to identify 42 core transcriptional regulators of the disease associated with inflammation (NFκB, IRF9, JUN, FOS, SRF), the activity of T cells in psoriatic lesions (STAT6, FOXP3, NFATC2, GATA3, TCF7, RUNX1), the hyperproliferation and migration of keratinocytes (JUN, FOS, NFIB, TFAP2A, TFAP2C) and lipid metabolism (TFAP2, RARA, VDR). In addition to the core regulators, we identified 38 transcription factors previously not associated with the disease that can clarify the pathogenesis of psoriasis. To illustrate these findings, we analyzed the regulatory role of one of the identified transcription factors (TFs), FOXA1. Using ChIP-seq and RNA-seq data, we concluded that the atypical expression of the FOXA1 TF is an important player in the disease as it inhibits the maturation of naive T cells into the (CD4+FOXA1+CD47+CD69+PD-L1(hi)FOXP3−) regulatory T cell subpopulation, therefore contributing to the development of psoriatic skin lesions.

Psoriasis was used as a model to analyze the pathogenetic pathways of immune-mediated inflammatory diseases, and the results of bioinformatic, molecular-genetic and proteomic studies are provided. Cell mechanisms, common for the pathogenesis of psoriasis, as well as Crohn's disease, are identified. New approaches for immune-mediated diseases are discussed.

The epigenetics of COVID-19 is a rapidly expanding field that reveals how the SARS-CoV-2 virus initiates alterations in the host’s genome, influencing the susceptibility to infection, the disease severity, and long-term consequences, known as “long COVID.” In this review, we describe the mechanisms utilized by the virus to manipulate the host epigenome, suppressing antiviral responses and creating a favorable environment for viral replication. We also highlight virus-induced epigenetic changes across diverse cell populations that contribute to COVID-19 pathogenesis. Notably, the virus reprograms hematopoietic stem and progenitor cells, leading to long-lasting alterations in innate immunity, a phenomenon known as “trained immunity.” These epigenetic modifications are maintained in differentiated daughter cells and may explain the persistent inflammation and other symptoms of long COVID. Furthermore, we discuss emerging epigenetic biomarkers of disease severity, including methylation signatures in genes such as AIM2, HLA-C, and PARP9, as well as dysregulated miRNA profiles. Understanding this complex interplay between the virus and the host’s epigenetic landscape is crucial for developing new therapeutic approaches that target specific epigenetic modifications to suppress pathological processes and improve clinical outcomes for COVID-19 patients.

Proinflammatory cytokines TNF, IFNG, and IL17 play an important role in eruption of psoriasis. The activation of epidermal keratinocytes with the named cytokines alters their terminal differentiation program and causes their hyperproliferation in the diseased skin. HaCaT cells, which are immortalized human keratinocytes, are often used as a cellular model of psoriasis. The aim of this study was to evaluate changes in gene expression and the proliferation rates in cultured HaCaT cells treated with TNF, IFNG, and IL17. We found that HaCaT cells decrease their proliferation rate in response to either IL17 or a combination TNF and IFNG. The analysis of microarray data discovered a group of 12 genes, which were downregulated in HaCaT after treatments with the named cytokines and upregulated in psoriatic lesional skin. Eight genes were important for DNA replication and they also contributed to two larger networks that regulated cell progression through the cell cycle. We conclude that HaCaT cells have a sufficient limitation as a cellular model of psoriasis due to their treatment with proinflammatory cytokines, namely TNF, IFNG, and IL17 does not increase their proliferation rate. Thus, the studies of psoriasis based on HaCaT cells as an experimental model shall take in account this important phenomenon.