No abstract

The transcription factor FOSL1 plays an important role in cell differentiation and tumorigenesis. Primarily, FOSL1 is crucial for the differentiation of several cell lineages, namely adipocytes, chondrocytes, and osteoblasts. In solid tumors, FOSL1 controls the progression of tumor cells through the epithelial–mesenchymal transformation. In this review, we summarize the available data on FOSL1 expression, stabilization, and degradation in the cell. We discuss how FOSL1 is integrated into the intracellular signaling mechanisms and provide a comprehensive analysis of FOSL1 influence on gene expression. We also analyze the pathological changes caused by altered Fosl1 expression in genetically modified mice. In addition, we dedicated a separate section of the review to the role of FOSL1 in human cancer. Primarily, we focus on the FOSL1 expression pattern in solid tumors, FOSL1 importance as a prognostic factor, and FOSL1 perspectives as a molecular target for anticancer therapy.

In our previous work, we built the model of PPARγ dependent pathways involved in the development of the psoriatic lesions. Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor and transcription factor which regulates the expression of many proinflammatory genes. We tested the hypothesis that low levels of PPARγ expression promote the development of psoriatic lesions triggering the IL17-related signaling cascade. Skin samples of normally looking and lesional skin donated by psoriasis patients and psoriatic CD3+ Tcells samples (n = 23) and samples of healthy CD3+ T cells donated by volunteers (n = 10) were analyzed by real-time PCR, ELISA and immunohistochemistry analysis. We found that the expression of PPARγ is downregulated in human psoriatic skin and laser treatment restores the expression. The expression of IL17, STAT3, FOXP3, and RORC in psoriatic skin before and after laser treatment were correlated with PPARγ expression according to the reconstructed model of PPARγ pathway in psoriasis.In conclusion, we report that PPARγ weakens the expression of genes that contribute in the development of psoriatic lesion. Our data show that transcriptional regulation of PPARγ expression by FOSL1 and by STAT3/FOSL1 feedback loop may be central in the psoriatic skin and T-cells.

MicroRNAs play an important role in the regulation of many cellular processes. Undoubtedly, these regulatory molecules are involved in the pathogenesis of asthma, and therefore can be potential targets for treatment.

We performed quantitative analysis of FOSL1 gene expression in lesional psoriatic skin. The expression of this gene in lesional psoriatic skin was significantly increased compared to that in unaffected areas. Enhanced FOSL1 expression significantly correlated with high psoriasis area and severity index (PASI). High level of FOSL1 gene expression was proposed to be a marker of pathological process activity in psoriasis.

Peutz-Jeghers syndrome is a rare autosomal dominant disorder. Approximately 1:25,000 to 1:280,000 cases are registered annually. The pathogenesis of the disease is based on the mutation of the STK 11 gene on chromosome 19. Peutz-Jeghers syndrome is characterized by several symptoms: the formation of multiple hamartomatous polyps primarily in the gastrointestinal tract and hyperpigmentation of the mucous membranes and skin. Patients with Peutz-Jeghers syndrome often develop various malignant neoplasms, mainly localized in the pancreas and colon. We describe Peutz-Jeghers syndrome in a girl 4 years 7 months old. Initially, the child was diagnosed with vitiligo due to complaints of depigmentation of the skin of the face and hands. During re-examination after half a year, foci of hyperpigmentation on the lip and mucous membranes of the oral cavity were noted. Esophagogastroduodenoscopy showed the presence of a polypous lump in the stomach. Genetic consultation confirmed the diagnosis of Peutz-Jeghers syndrome. The absence of family history indicates a sporadic case characterized by diseases with an autosomal-dominant mode of inheritance. This clinical case demonstrates the need for gastroenterological and genetic examinations in the presence of lesions on the oral mucosa and the vermillion border of the lips to confirm or exclude Peutz-Jeghers syndrome.

Background Plaque psoriasis is a chronic autoimmune disorder characterized by the development of red scaly plaques. To date psoriasis lesional skin transcriptome has been extensively studied, whereas only few proteomic studies of psoriatic skin are available. Aim The aim of this study was to compare protein expression patterns of lesional and normally looking skin of psoriasis patients with skin of the healthy volunteers, reveal differentially expressed proteins and identify changes in cell metabolism caused by the disease. Methods Skin samples of normally looking and lesional skin donated by psoriasis patients (n = 5) and samples of healthy skin donated by volunteers (n = 5) were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). After protein identification and data processing, the set of differentially expressed proteins was subjected to protein ontology analysis to characterize changes in biological processes, cell components and molecular functions in the patients’ skin compared to skin of the healthy volunteers. The expression of selected differentially expressed proteins was validated by ELISA and immunohistochemistry. Results The performed analysis identified 405 and 59 differentially expressed proteins in lesional and normally looking psoriatic skin compared to healthy control. In normally looking skin of the patients, we discovered decreased expression of KNG1, APOE, HRG, THBS1 and PLG. Presumably, these changes were needed to protect the epidermis from spontaneous activation of kallikrein-kinin system and delay the following development of inflammatory response. In lesional skin, we identified several large groups of proteins with coordinated expression. Mainly, these proteins were involved in different aspects of protein and RNA metabolism, namely ATP synthesis and consumption; intracellular trafficking of membrane-bound vesicles, pre-RNA processing, translation, chaperoning and degradation in proteasomes/immunoproteasomes. Conclusion Our findings explain the molecular basis of metabolic changes caused by disease in skin lesions, such as faster cell turnover and higher metabolic rate. They also indicate on downregulation of kallikrein-kinin system in normally looking skin of the patients that would be needed to delay exacerbation of the disease. Data are available via ProteomeXchange with identifier PXD021673.

Interactions of genes in intersecting signaling pathways, as well as environmental influences, are required for the development of psoriasis. Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor and transcription factor which inhibits the expression of many proinflammatory genes. We tested the hypothesis that low levels of PPARγ expression promote the development of psoriatic lesions. We combined experimental results and network functional analysis to reconstruct the model of PPARγ-downregulated signaling in psoriasis. We hypothesize that the expression of IL17, STAT3, FOXP3, and RORC and FOSL1 genes in psoriatic skin is correlated with the level of PPARγ expression, and they belong to the same signaling pathway that regulates the development of psoriasis lesion.