Alternative splicing is not a key source of chemerin isoforms diversity.

BACKGROUND: Chemerin is a chemoattractant protein with adipokine and antimicrobial properties encoded by the retinoic acid receptor responder 2 (RARRES2) gene. Chemerin bioactivity largely depends on carboxyl-terminal proteolytic processing that generates chemerin isoforms with different chemotactic, regulatory, and antimicrobial potentials. While these mechanisms are relatively well known, the role of alternative splicing in generating isoform diversity remains obscure. METHODS AND RESULTS: Using rapid amplification of cDNA ends (RACE) PCR, we determined RARRES2 transcript variants present in mouse and human tissues and identified novel transcript variant 4 of mouse Rarres2 encoding mChem153K. Moreover, analyses of real-time quantitative PCR (RT-qPCR) and publicly-available next-generation RNA sequencing (RNA-seq) datasets showed that different alternatively spliced variants of mouse Rarres2 are present in mouse tissues and their expression patterns were unaffected by inflammatory and infectious stimuli except brown adipose tissue. However, only one transcript variant of human RARRES2 was present in liver and adipose tissue. CONCLUSION: Our findings indicate a limited role for alternative splicing in generating chemerin isoform diversity under all tested conditions.

Accessible Tutoring Platform Using Audio-Tactile Graphics Adapted for Visually Impaired People.

One of the problems faced by people with blindness is access to materials presented in graphical form. There are many alternative forms of providing such information, but they are very often ineffective or have certain limitations. The development of mobile devices and touch sensors enabled the development of new tools to support such people. This study presents a solution called an accessible tutoring platform, using audio-tactile graphics for people with blindness. We aimed to research the influence of the developed platform for the alternative presentation of graphics information on better memorizing, recognizing, and learning. Another goal of the research was to verify the effectiveness of the proposed method for the alternative presentation of audio-tactile graphics. The effectiveness of the proposed solution was verified quantitatively and qualitatively on two groups of blind students from primary and secondary schools with the use of a developed platform and prepared materials for learning mathematics. The obtained research results show that the proposed method of verifying students' knowledge and auto-selecting exercises with adapted audio description positively influences the improvement of learning effectiveness.

Soluble mediators in the function of the epidermal-immune-neuro unit in the skin.

Skin is the largest, environmentally exposed (barrier) organ, capable of integrating various signals into effective defensive responses. The functional significance of interactions among the epidermis and the immune and nervous systems in regulating and maintaining skin barrier function is only now becoming recognized in relation to skin pathophysiology. This review focuses on newly described pathways that involve soluble mediator-mediated crosstalk between these compartments. Dysregulation of these connections can lead to chronic inflammatory diseases and/or pathologic conditions associated with chronic pain or itch.

Redox Active Antimicrobial Peptides in Controlling Growth of Microorganisms at Body Barriers.

Epithelia in the skin, gut and other environmentally exposed organs display a variety of mechanisms to control microbial communities and limit potential pathogenic microbial invasion. Naturally occurring antimicrobial proteins/peptides and their synthetic derivatives (here collectively referred to as AMPs) reinforce the antimicrobial barrier function of epithelial cells. Understanding how these AMPs are functionally regulated may be important for new therapeutic approaches to combat microbial infections. Some AMPs are subject to redox-dependent regulation. This review aims to: (i) explore cysteine-based redox active AMPs in skin and intestine; (ii) discuss casual links between various redox environments of these barrier tissues and the ability of AMPs to control cutaneous and intestinal microbes; (iii) highlight how bacteria, through intrinsic mechanisms, can influence the bactericidal potential of redox-sensitive AMPs.

Metagenomic Studies in Inflammatory Skin Diseases.

Next-generation sequencing (NGS) technologies together with an improved access to compute performance led to a cost-effective genome sequencing over the past several years. This allowed researchers to fully unleash the potential of genomic and metagenomic analyses to better elucidate two-way interactions between host cells and microbiome, both in steady-state and in pathological conditions. Experimental research involving metagenomics shows that skin resident microbes can influence the cutaneous pathophysiology. Here, we review metagenome approaches to study microbiota at this barrier site. We also describe the consequences of changes in the skin microbiota burden and composition, mostly revealed by these technologies, in the development of common inflammatory skin diseases.

The methylation status of the chemerin promoter region located from - 252 to + 258 bp regulates constitutive but not acute-phase cytokine-inducible chemerin expression levels.

Chemerin is a chemoattractant protein with adipokine properties encoded by the retinoic acid receptor responder 2 (RARRES2) gene. It has gained more attention in the past few years due to its multilevel impact on metabolism and immune responses. However, mechanisms controlling the constitutive and regulated expression of RARRES2 in a variety of cell types remain obscure. To our knowledge, this report is the first to show that DNA methylation plays an important role in the cell-specific expression of RARRES2 in adipocytes, hepatocytes, and B lymphocytes. Using luciferase reporter assays, we determined the proximal fragment of the RARRES2 gene promoter, located from - 252 to + 258 bp, to be a key regulator of transcription. Moreover, we showed that chemerin expression is regulated in murine adipocytes by acute-phase cytokines, interleukin 1ß and oncostatin M. In contrast with adipocytes, these cytokines exerted a weak, if any, response in mouse hepatocytes, suggesting that the effects of IL-1ß and OSM on chemerin expression is specific to fat tissue. Together, our findings highlight previously uncharacterized mediators and mechanisms that control chemerin expression.

Differences in Staining for Neutrophil Elastase and its Controlling Inhibitor SLPI Reveal Heterogeneity among Neutrophils in Psoriasis.

Neutrophils are broadly classified into conventional neutrophils (PMNs) and low-density granulocytes (LDGs). LDGs are better than PMNs at generating neutrophil extracellular traps (NETs), which may contribute to the pathology of autoimmune diseases. We hypothesized that LDGs and PMNs differ in their levels of unrestrained NE that supports NET generation. Here, we show that individuals with psoriasis contain elevated levels of LDGs and that in contrast to PMNs, the LDGs display higher staining for NE and lower staining for its inhibitor SLPI. The heterogeneity between blood-derived LDGs and PMNs was somewhat reminiscent of the differences in the NE and SLPI staining patterns observed in psoriasis skin-infiltrating neutrophils. Distinctive staining for NE and SLPI in LDGs and PMNs did not result from differences in their protein levels nor manifested in higher total proteolytic activity of NE in LDGs; rather, it likely depended on different cytosolic sequestration of these proteins. The disparate profile of NE and SLPI in LDGs and PMNs coincided with altered migratory responses of these cells to cutaneous chemoattractants. Collectively, differential NE and SLPI staining identifies common attributes of both circulating and skin-infiltrating neutrophils, which may guide neutrophil migration to distinct skin regions and determine the localization of LDGs-mediated cutaneous pathology.

Architecture of antimicrobial skin defense.

The skin is the largest and the most exposed organ in the body and its defense is regulated at several anatomical levels. Here, we explore how skin layers, including the epidermis, dermis, adipose tissue, and skin appendages, as well as cutaneous microbiota, contribute to the function of skin antimicrobial defense. We highlight recent studies that reveal the differential and complementary responses of skin layers to bacterial, viral, and fungal infection. In particular, we focus on key soluble mediators in the layered skin defense, such as antimicrobial peptides, as well as on lipid antimicrobials, cytokines, chemokines, and barrier-maintaining molecules. We include our own evaluative analyses of transcriptomic datasets of human skin to map the involvement of antimicrobial peptides in skin protection under both steady state and infectious conditions. Furthermore, we explore the versatility of the mechanisms underlying skin defense by highlighting the role of the immune and nervous systems in their interaction with cutaneous microbes, and by illustrating the multifunctionality of selected antimicrobial peptides in skin protection.

The antimicrobial activity of chemerin-derived peptide p4 requires oxidative conditions.

Chemerin is a leukocyte attractant, adipokine, and antimicrobial protein abundantly produced in the skin epidermis. Despite the fact that most of the bactericidal activity present in human skin exudates is chemerin-dependent, just how chemerin shapes skin defenses remains obscure. Here we demonstrate that p4, a potent antimicrobial human chemerin peptide derivative, displays killing activity against pathogenic methicillin-resistant Staphylococcus aureus strains and suppresses microbial growth in a topical skin infection model. Mechanistically, we show that p4 homodimerization is required for maximal bactericidal activity and that an oxidative environment, such as at the skin surface, facilitates p4 disulfide bridge formation, required for the dimerization. p4 led to rapid damage of the bacterial internal membrane and inhibited the interaction between the membranous cytochrome bc1 complex and its redox partner, cytochrome c These results suggest that a chemerin p4-based defense strategy combats bacterial challenges at the skin surface.

Tutoring math platform accessible for visually impaired people.

BACKGROUND: There are many problems with teaching and assessing impaired students in higher education, especially in technical science, where the knowledge is represented mostly by structural information like: math formulae, charts, graphs, etc. Developing e-learning platform for distance education solves this problem only partially due to the lack of accessibility for the blind. METHOD: The proposed method is based on the decomposition of the typical mathematical exercise into a sequence of elementary sub-exercises. This allows for interactive resolving of math exercises and assessment of the correctness of exercise solutions at every stage. The presented methods were prepared and evaluated by visually impaired people and students. RESULTS: The article presents the accessible interactive tutoring platform for math teaching and assessment, and experience in exploring it. The results of conducted research confirm good understanding of math formulae described according to elaborated rules. Regardless of the level of complexity of the math formulae the level of math formulae understanding is higher for alternative structural description. CONCLUSIONS: The proposed solution enables alternative descriptions of math formulae. Based on the research results, the tool for computer-aided interactive learning of mathematics adapted to the needs of the blind has been designed, implemented and deployed as a platform for on-site and online and distance learning. The designed solution can be very helpful in overcoming many barriers that occur while teaching impaired students.

Antimicrobial and Attractant Roles for Chemerin in the Oral Cavity during Inflammatory Gum Disease.

Periodontal inflammation is one of the most common chronic inflammatory conditions in humans. Despite recent advances in identifying and characterizing oral microbiota dysbiosis in the pathogenesis of gum disease, just how host factors maintain a healthy homeostatic oral microbial community or prevent the development of a pathogenic oral microbiota remains poorly understood. An important determinant of microbiota fate is local antimicrobial proteins. Here, we report that chemoattractant protein chemerin, which we recently identified as a potent endogenous antimicrobial agent in body barriers such as the skin, is present in the oral cavity under homeostatic and inflammatory conditions. Chemerin and a chemerin-derived antimicrobial peptide are bactericidal against select bacteria strategically positioned in dental biofilm. Gingival crevicular samples from patients with gingivitis but not periodontitis contain abundant bioactive chemerin capable of inducing CMKLR1-dependent leukocyte migration. Gingipains secreted by the periodontopathogen P. gingivalis inactivate chemerin. Together, these data suggest that as an antimicrobial agent and leukocyte chemoattractant, chemerin likely contributes to antimicrobial immune defense in the oral cavity.