The Immunology of Psoriasis-Current Concepts in Pathogenesis.

Psoriasis is one of the most common inflammatory skin diseases with a chronic, relapsing-remitting course. The last decades of intense research uncovered a pathological network of interactions between immune cells and other types of cells in the pathogenesis of psoriasis. Emerging evidence indicates that dendritic cells, TH17 cells, and keratinocytes constitute a pathogenic triad in psoriasis. Dendritic cells produce TNF-α and IL-23 to promote T cell differentiation toward TH17 cells that produce key psoriatic cytokines IL-17, IFN-γ, and IL-22. Their activity results in skin inflammation and activation and hyperproliferation of keratinocytes. In addition, other cells and signaling pathways are implicated in the pathogenesis of psoriasis, including TH9 cells, TH22 cells, CD8+ cytotoxic cells, neutrophils, γδ T cells, and cytokines and chemokines secreted by them. New insights from high-throughput analysis of lesional skin identified novel signaling pathways and cell populations involved in the pathogenesis. These studies not only expanded our knowledge about the mechanisms of immune response and the pathogenesis of psoriasis but also resulted in a revolution in the clinical management of patients with psoriasis. Thus, understanding the mechanisms of immune response in psoriatic inflammation is crucial for further studies, the development of novel therapeutic strategies, and the clinical management of psoriasis patients. The aim of the review was to comprehensively present the dysregulation of immune response in psoriasis with an emphasis on recent findings. Here, we described the role of immune cells, including T cells, B cells, dendritic cells, neutrophils, monocytes, mast cells, and innate lymphoid cells (ILCs), as well as non-immune cells, including keratinocytes, fibroblasts, endothelial cells, and platelets in the initiation, development, and progression of psoriasis.

TMEM244 Is a Long Non-Coding RNA Necessary for CTCL Cell Growth.

Transmembrane protein 244 (TMEM244) was annotated to be a member of the TMEM family, which are is a component of cell membranes and is involved in many cellular processes. To date, the expression of the TMEM244 protein has not been experimentally confirmed, and its function has not been clarified. Recently, the expression of the TMEM244 gene was acknowledged to be a diagnostic marker for Sézary syndrome, a rare cutaneous T-cell lymphoma (CTCL). In this study, we aimed to determine the role of the TMEM244 gene in CTCL cells. Two CTCL cell lines were transfected with shRNAs targeting the TMEM244 transcript. The phenotypic effect of TMEM244 knockdown was validated using green fluorescent protein (GFP) growth competition assays and AnnexinV/7AAD staining. Western blot analysis was performed to identify the TMEM244 protein. Our results indicate that TMEM244 is not a protein-coding gene but a long non-coding RNA (lncRNA) that is necessary for the growth of CTCL cells.

Role of Histone Deacetylases in T-Cell Development and Function.

Histone deacetylases (HDACs) are a group of enzymes called "epigenetic erasers". They remove the acetyl group from histones changing the condensation state of chromatin, leading to epigenetic modification of gene expression and various downstream effects. Eighteen HDACs have been identified and grouped into four classes. The role of HDACs in T-cells has been extensively studied, and it has been proven that many of them are important players in T-cell development and function. In this review, we present the current state of knowledge on the role of HDACs in the early stages of T-cell development but also in the functioning of mature lymphocytes on the periphery, including activation, cytokine production, and metabolism regulation.