Innate immune-related receptors in normal and psoriatic skin

The Role of Alarmins in the Pathogenesis of Rheumatoid Arthritis, Osteoarthritis, and Psoriasis

Alarmins are immune-activating factors released after cellular injury or death. By secreting alarmins, cells can interact with immune cells and induce a variety of inflammatory responses. The broad family of alarmins involves several members, such as high-mobility group box 1, S100 proteins, interleukin-33, and heat shock proteins, among others. Studies have found that the concentrations and expression profiles of alarmins are altered in immune-mediated diseases. Furthermore, they are involved in the pathogenesis of inflammatory conditions. The aim of this narrative review is to present the current evidence on the role of alarmins in rheumatoid arthritis, osteoarthritis, and psoriasis. We discuss their potential involvement in mechanisms underlying the progression of these diseases and whether they could become therapeutic targets. Moreover, we summarize the impact of pharmacological agents used in the treatment of these diseases on the expression of alarmins.

Damage-Associated Molecular Patterns, a Class of Potential Psoriasis Drug Targets

Psoriasis is a chronic skin disorder that involves both innate and adaptive immune responses in its pathogenesis. Local tissue damage is a hallmark feature of psoriasis and other autoimmune diseases. In psoriasis, damage-associated molecular patterns (DAMPs) released by damaged local tissue act as danger signals and trigger inflammatory responses by recruiting and activating immune cells. They also stimulate the release of pro-inflammatory cytokines and chemokines, which exacerbate the inflammatory response and contribute to disease progression. Recent studies have highlighted the role of DAMPs as key regulators of immune responses involved in the initiation and maintenance of psoriatic inflammation. This review summarizes the current understanding of the immune mechanism of psoriasis, focusing on several important DAMPs and their mechanisms of action. We also discussed the potential of DAMPs as diagnostic and therapeutic targets for psoriasis, offering new insights into the development of more effective treatments for this challenging skin disease.

Th2 Cytokines Affect the Innate Immune Barrier without Impairing the Physical Barrier in a 3D Model of Normal Human Skin

(1) Background: Atopic dermatitis is one of the most common inflammatory skin diseases characterized by T helper (Th) 2 and Th22 cells producing interleukin (IL)-4/IL-13 and IL-22, respectively. The specific contribution of each cytokine to the impairment of the physical and the immune barrier via Toll-like receptors (TLRs) is poorly addressed concerning the epidermal compartment of the skin. (2) Methods: The effect of IL-4, IL-13, IL-22, and the master cytokine IL-23 is evaluated in a 3D model of normal human skin biopsies (n = 7) at the air-liquid interface for 24 and 48 h. We investigated by immunofluorescence the expressions of (i) claudin-1, zonula occludens (ZO)-1 filaggrin, involucrin for the physical barrier and (ii) TLR2, 4, 7, 9, human beta-defensin 2 (hBD-2) for the immune barrier. (3) Results: Th2 cytokines induce spongiosis and fail in impairing tight junction composition, while IL-22 reduces and IL-23 induces claudin-1 expression. IL-4 and IL-13 affect the TLR-mediated barrier largely than IL-22 and IL-23. IL-4 early inhibits hBD-2 expression, while IL-22 and IL-23 induce its distribution. (4) Conclusions: This experimental approach looks to the pathogenesis of AD through molecular epidermal proteins rather than cytokines only and paves the way for tailored patient therapy.

Alarmins in autoimmune diseases

Alarmins are endogenous, constitutively expressed, chemotacting and immune activating proteins or peptides released because of non-programmed cell death (i.e. infections, trauma, etc). They are considered endogenous damage-associated molecular patterns (DAMPs), able to induce a sterile inflammation. In the last years, several studies highlighted a possible role of different alarmins in the pathogenesis of various autoimmune and immune-mediated diseases. We reviewed the relevant literature about this topic, for about 160 articles. Particularly, we focused on systemic autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, idiopathic inflammatory myopathies, ANCA-associated vasculitides, Behçet's disease) and cutaneous organ-specific autoimmune diseases (vitiligo, psoriasis, alopecia, pemphigo). Finally, we discussed about future perspectives and potential therapeutic implications of alarmins in autoimmune diseases. In fact, identification of receptors and downstream signal transducers of alarmins may lead to the identification of antagonistic inhibitors and agonists, with the capacity to modulate alarmins-related pathways and potential therapeutic applicability.

Relationship between Immune Cells, Depression, Stress, and Psoriasis: Could the Use of Natural Products Be Helpful?

Psoriasis is one of the most widespread chronic inflammatory skin diseases, affecting about 2%-3% of the worldwide adult population. The pathogenesis of this disease is quite complex, but an interaction between genetic and environmental factors has been recognized with an essential modulation of inflammatory and immune responses in affected patients. Psoriatic plaques generally represent the clinical psoriatic feature resulting from an abnormal proliferation and differentiation of keratinocytes, which cause dermal hyperplasia, skin infiltration of immune cells, and increased capillarity. Some scientific pieces of evidence have reported that psychological stress may play a key role in psoriasis, and the disease itself may cause stress conditions in patients, thus reproducing a vicious cycle. The present review aims at examining immune cell involvement in psoriasis and the relationship of depression and stress in its pathogenesis and development. In addition, this review contains a focus on the possible use of natural products, thus pointing out their mechanism of action in order to counteract clinical and psychological symptoms.

Cutaneous Toxicities in the Setting of Immune Checkpoint Blockade:: The Era of Oncodermatopathology

Advancements in cancer therapy with monoclonal immune checkpoint antibody blockade have impacted the practice of all medical specialties. Cutaneous immune-related adverse events (irAEs) are a frequent, unintended, off-target consequence of immune checkpoint inhibitor (ICI) therapy that have ushered in the era of oncodermatopathology. Knowledge of the diverse morphologic types of cutaneous irAEs from ICI therapy allows further classification of cutaneous irAEs according to major histopathologic reaction patterns. Early studies suggest that immune mechanisms of lichenoid dermatitis irAE, psoriasiform dermatitis irAE, and bullous pemphigoid irAE show some similarities and differences from their histopathologic counterparts not associated with ICI therapy.

Toll-Like Receptors in Dermatology, Venereology, and Leprosy

Toll-like receptors (TLRs) represent a family of Type I transmembrane proteins characterized by an extracellular leucine-rich repeat domain and a cytoplasmic domain. TLRs represent a conserved group of receptors which help the immune system to function properly. Different TLRs are associated with an array of skin diseases. TLR agonists and antagonists have great potential for the treatment of allergic and inflammatory diseases.

Antibodies to Heat Shock Proteins 90α and 90β in Psoriasis

One of many hypotheses of psoriasis pathogenesis supposes an overexpression of heat shock proteins (Hsps) in different skin layers and systemic immunologic response to them. Hsp90 is one of the most abundant chaperone in eukaryotic cells. The number of studies concerning the role of Hsp90 and anti-Hsp90 antibodies in etiopathogenesis of various diseases is also constantly expanding. Still, there are not many reports concerning potential involvement of this Hsp family or anti-Hsp90 immunization in pathomechanism of psoriasis. The aim of the study was the estimation of anti-Hsp90α and anti-Hsp90β IgG antibodies in the sera of the psoriatic patients at different phases of disease activity in comparison to the sera of healthy individuals. The study material consisted of sera from psoriasis patients (n = 80) in active phase and in the remission phase and healthy individuals (n = 80). Concentrations of anti-Hsp90α and anti-Hsp90β IgG antibodies were determined using ELISA technique. In the patients with psoriasis (both in the active phase of the disease and in the remission phase) concentrations of anti-Hsp90α antibodies were significantly higher than in healthy individuals and they correlated positively with psoriasis area severity index values. The mean concentrations of anti-Hsp90β antibodies in the psoriatic patients and healthy controls were comparable. The obtained results indicate an existence of increased immunological response to Hsp90α in psoriasis. It may suggest the role of the extracellular form of this chaperone and/or anti-Hsp90α antibodies in etiopathogenesis of this dermatosis. The inhibition of Hsp90α may represent a novel therapeutic approach to treat psoriasis.

Heat shock proteins in the physiology and pathophysiology of epidermal keratinocytes

Heat shock proteins (HSPs), a large group of highly evolutionary conserved proteins, are considered to be main elements of the cellular proteoprotection system. HSPs are encoded by genes activated during the exposure of cells to proteotoxic factors, as well as by genes that are expressed constitutively under physiological conditions. HSPs, having properties of molecular chaperones, are involved in controlling/modulation of multiple cellular and physiological processes. In the presented review, we summarize the current knowledge on HSPs in the biology of epidermis, the outer skin layer composed of stratified squamous epithelium. This tissue has a vital barrier function preventing from dehydratation due to passive diffusion of water out of the skin, and protecting from infection and other environmental insults. We focused on HSPB1 (HSP27), HSPA1 (HSP70), HSPA2, and HSPC (HSP90), because only these HSPs have been studied in the context of physiology and pathophysiology of the epidermis. The analysis of literature data shows that HSPB1 plays a role in the regulation of final steps of keratinization; HSPA1 is involved in the cytoprotection, HSPA2 contributes to the early steps of keratinocyte differentiation, while HSPC is essential in the re-epithelialization process. Since HSPs have diverse functions in various types of somatic tissues, in spite of multiple investigations, open questions still remain about detailed roles of a particular HSP isoform in the biology of epidermal keratinocytes.

Gene expression profiling of lichenoid dermatitis immune-related adverse event from immune checkpoint inhibitors reveals increased CD14+ and CD16+ monocytes driving an innate immune response

BACKGROUND

Cancer patients receiving antibodies abrogating immune checkpoint pathways may develop a diverse array of immune-related adverse events (irAEs), of which lichenoid dermatitis (LD) is the most common. The mechanism driving the emergence of these irAEs remain understudied, underscoring a critical need to determine the unique gene expression profiles and immune composition in LD-irAE.

METHODS

LD-irAE (n = 3) and benign lichenoid keratosis (BLK) control (n = 3) were profiled with NanoString nCounter PanCancer Immune Profiling Panel interrogating the mRNA levels of 770 genes. Immunohistochemical (IHC) studies (n = 14 samples) for CD14, CD16, T-Bet, Gata-3, and FoxP3 were further evaluated using Aperio digital image analysis.

RESULTS

The LD-irAE showed downregulation of 93 mRNA transcripts (P < 0.05) and upregulation of 74 mRNA transcripts (P < 0.04) including toll-like receptor (TLR) 2 and TLR4 (P < 0.05). CD14⁺ and CD16⁺ monocytes quantified by IHC (H-score) were higher in LD-irAE than in the BLK control (P < 0.05). The immune composition of LD-irAE exhibited higher numbers of T-Bet⁺ (Th1) cells compared with Gata-3⁺ (Th2) cells (P = 0.016) and lower numbers of FoxP3 (T regulatory) cells (P = 0.008).

CONCLUSIONS

LD-irAE exhibited activation of CD14/TLR innate immune response with increased CD14⁺ and CD16⁺ monocytes compared with BLK control. CD14/TLR signaling may drive the development of LD-irAE.

Accelerated Wound Healing by Fibroblasts Differentiated from Human Embryonic Stem Cell-Derived Mesenchymal Stem Cells in a Pressure Ulcer Animal Model

Fibroblasts synthesize and secrete dermal collagen, matrix proteins, growth factors, and cytokines. These characteristics of fibroblasts provide a potential way for fibroblast therapy to treat skin ulcers more effectively than conventional therapies such as cytokine therapy and negative pressure wound therapy. However, the obstacle to the commercialization of fibroblast therapy is the limited supply of cells with consistent quality. In this study, we tested whether human embryonic stem cell-derived mesenchymal stem cells (hESC-MSCs) could be differentiated into fibroblasts considering that they have characteristics of high differentiation rates, unlimited proliferation possibility from a single colony, and homogeneity. As a result, hESC-MSC-derived fibroblasts (hESC-MSC-Fbs) showed a significant increase in the expression of type I and III collagen, fibronectin, and fibroblast-specific protein-1 (FSP-1). Besides, vessel formation and wound healing were enhanced in hESC-MSC-Fb-treated skin tissues compared to PBS- or hESC-MSC-treated skin tissues, along with decreased IL-6 expression at 4 days after the formation of pressure ulcer wound in a mouse model. In view of the limited available cell sources for fibroblast therapy, hESC-MSC-Fbs show a promising potential as a commercial cell therapy source to treat skin ulcers.

Immune receptors CD40 and CD86 in oral keratinocytes and implications for oral lichen planus

Lichen planus (LP) is a chronic T-cell-mediated mucocutaneous inflammatory disease that targets stratified epithelia, including those lining the oral cavity. The intraoral variant of LP (OLP) is associated with interferon (IFN)-γ production by infiltrating T lymphocytes; however, the role of epithelial cells in the etiopathogenesis OLP is not completely understood. There is however a growing body of evidence regarding the involvement of epithelial-derived cytokines, immune receptors, and costimulatory molecules in the pathobiological processes that promote and sustain OLP. In the present study, we used a reverse transcriptase-polymerase chain reaction assay to assess whether CD40-a receptor found mainly on antigen presenting cells-and the costimulatory molecule CD86 were expressed in oral keratinocytes (three strains of primary normal oral keratinocytes and the H357 cell line) in the presence or absence of IFN-γ. To further characterize the involvement of CD40 in OLP, expression and distribution of receptor and ligand (CD40/CD154) in tissues from OLP were evaluated by immunohistochemistry. The present results are the first to show that both CD40 and CD86 are constitutively expressed at low levels in oral keratinocytes and that their expression was enhanced by IFN-γ stimulation. The intensity of CD40 staining in OLP tissues was strong. Taken together, the results strongly suggest that CD40 and CD86 play a role in the pathophysiology of oral inflammatory diseases such as OLP.

Toll-Like Receptor Function in Acute Wounds

Significance: Inflammation is an integral part of immune response and supports optimal wound healing in adults. Inflammatory cells such as neutrophils, macrophages, dendritic cells, lymphocytes, and mast cells produce important cytokines, chemokines, and growth factors. These immune cells interact with keratinocytes, fibroblasts, and endothelial cells (ECs), as well as the extracellular matrix within a complicated network that promotes and regulates wound healing. Aberrant and persistent inflammation may result in delayed wound healing, scar formation, or chronic wounds. Targeting the molecules involved in the inflammatory response may have great potential therapeutic value. Recent Advances and Critical Issues: Toll-like receptors (TLRs) are pattern recognition receptors that recognize pathogen-associated molecular patterns from microbes or danger-associated molecular patterns from damaged cells. The discovery of TLRs sheds new light on the mechanism by which the inflammatory or innate immune response is initiated in wound healing. Convincing evidence now shows that multiple types of cells, including infiltrating or resident inflammatory cells, keratinocytes, fibroblasts, and ECs, express specific types of TLRs. Experimental reduction of certain TLRs or treatment of wounds with TLR ligands has been shown to affect wound healing. A better understanding of the involvement of TLRs in the innate immune response during skin wound healing may suggest novel strategies to improve the quality of tissue repair. Future Directions: Despite the indisputable role of TLRs in regulating the immune response in acute wound healing, the functions of TLRs that are relevant to human wound healing and chronic wounds are poorly understood.

Epidermal barrier reaction to an in vitro psoriatic microenvironment

Keratinocytes (KCs) and Langerhans cells (LCs) contribute to create the epidermal barrier. To form a functional epidermis, KCs express filaggrin and Toll-like Receptors (TLRs). LCs are the first line of epidermal defence and can be activated by interleukin (IL)-17 and Tumor Necrosis Factor (TNF)-alpha. In psoriasis, an alteration of TLR expression, a defective expression of filaggrin, and LC activation occur. In organotypic cultures of human skin we investigated the interplay between IL-17 and TNF-alpha on i) expression of filaggrin, TLR2, 7 and 9, and Nuclear Factor (NF)-kB localization by immunofluorescence and ii) LC ultrastructural features by transmission electron microscopy. Normal human skin was obtained after aesthetic surgery (n=7), overnight incubated in a Transwell system, and exposed to TNF-alpha and/or IL-17 for 24 (T24), 48 (T48), and 72 (T72) hours. Cytokines always influenced the expression of filaggrin. TNF-alpha alone activated LCs only starting from T48. TLR2 and TLR7 expressions were affected at T24 by IL-17 and the combination of cytokines, but not by TNF-alpha. TLR9-positive cells were detectable in the granular layer after cytokine exposure. A nuclear localization of NF-kB was always observed after cytokine incubation. In conclusion, each cytokine possess an intrinsic activity on the different components of the epidermal barrier.

Toll-like receptors: promising therapeutic targets for inflammatory diseases

The health of living organisms is constantly challenged by bacterial and viral threats. The recognition of pathogenic microorganisms by diverse receptors triggers a variety of host defense mechanisms, leading to their eradication. Toll-like receptors (TLRs), which are type I transmembrane proteins, recognize specific signatures of the invading microbes and activate a cascade of downstream signals inducing the secretion of inflammatory cytokines, chemokines, and type I interferons. The TLR response not only counteracts the pathogens but also initiates and shapes the adaptive immune response. Under normal conditions, inflammation is downregulated after the removal of the pathogen and cellular debris. However, a dysfunctional TLR-mediated response maintains a chronic inflammatory state and leads to local and systemic deleterious effects in host cells and tissues. Such inappropriate TLR response has been attributed to the development and progression of multiple diseases such as cancer, autoimmune, and inflammatory diseases. In this review, we discuss the emerging role of TLRs in the pathogenesis of inflammatory diseases and how targeting of TLRs offers a promising therapeutic strategy for the prevention and treatment of various inflammatory diseases. Additionally, we highlight a number of TLR-targeting agents that are in the developmental stage or in clinical trials.

Therapeutic targeting of Toll-like receptors: a review of Toll-like receptors and their signaling pathways in psoriasis

INTRODUCTION

Expression of various Toll-like receptors (TLR) in keratinocytes (KCs) has offered new insights into the pathogenesis of psoriasis. When plasmacytoid dendritic cells (pDCs) are scarce in established psoriatic lesions, KCs take the responsibility to secrete IFN type 1 through TLR9 activation. Antagonists of TLR7 and TLR8 and anti-IL-12/IL-23 substances have shown promising results in treating psoriasis. Areas covered: References in this study were extracted from Scopus, PubMed and Embase databases by the search term: ('Toll-Like Receptors' OR 'TLR') AND ('Psoriasis' OR 'Arthritis, Psoriatic' OR 'PsA'). Expert commentary: As the prevailing cell type, KCs play a major role in the maintenance of psoriatic lesions. By specific upregulation of IL-36 R, KCs can start the IL-23/IL-12 axis, leading to production of major culprits of psoriatic phenotype IL-17 and IL-22. Targeting IL-36 R could be considered as a new therapeutic target to eliminate cutaneous manifestations of psoriasis.

Immunohistochemical study of toll-like receptors 2, 4, and 9 expressions in pemphigus and bullous pemphigoid lesions

Pemphigus and bullous pemphigoid (BP) are severe autoimmune skin diseases. Whether innate immunity could be a trigger or a part of the pathogeneses is unknown. Toll-like receptors (TLRs) are important components of the innate immune system, with no previous evaluation of TLRs in autoimmune bullous diseases. This work aims to investigate TLRs 2, 4, and 9 expressions in pemphigus and bullous pemphigoid. Thirty-six patients with pemphigus vulgaris (PV), pemphigus foliaceus (PF), bullous pemphigoid (BP), and six healthy controls were studied. Skin biopsies from the patients and the controls were examined immunohistochemically for TLR2, 4, and 9 expressions. The TLR4 expressed mainly at the basal layer of epidermis in controls, but in the cases with autoimmune bullous diseases, TLR4 staining located at basal layer and suprabasal layer, even superficial layer of epidermis. The immunostaining-intensity-distribution (IID) index of TLR4 in patients with PF (13.83, P = 0.001), PV (13.08, P = 0.003), and BP (11.42, P = 0.042) were significantly higher than that of the controls (6.17). TLR2 and TLR9 showed no significantly changes at epidermal expression (P > 0.05) compared with controls. There was no correlation found between the expressions of these TLRs. This work, thus, shows a re-localization of TLR4 expression sites with increased expression in pemphigus and bullous pemphigoid lesions. Targeting TLR4 signaling is expected to be a novel treatment strategy for autoimmune bullous diseases.

Controlling the origins of inflammation with a photoactive lipopeptide immunopotentiator

Inflammatory immune responses are mediated by signaling molecules that are both produced by and recognized across highly heterogeneous cell populations. As such, the study of inflammation using traditional immunostimulants is complicated by paracrine and autocrine signaling, which obscures the origin of a propagating response. To address this challenge, we developed a small-molecule probe that can photosensitize immune cells, thus allowing light-mediated inflammation. This probe was used to control the origin of inflammation using light. Following this motif, inflammation was initiated from fibroblasts or dendritic cells. The contributions of fibroblasts and dendritic cells in initiating inflammation in heterogeneous co-culture are reported, thus providing insights into the future development of vaccines and treatment of inflammation.

CpGB DNA activates dermal macrophages and specifically recruits inflammatory monocytes into the skin

Toll-like receptor 9 (TLR9) drives innate immune responses after recognition of foreign or endogenous DNA containing unmethylated CpG motifs. DNA-mediated TLR9 activation is highly implicated in the pathogenesis of several autoimmune skin diseases, yet its contribution to the inflammation seen in these diseases remains unclear. In this study, TLR9 ligand, CpGB DNA, was administered to mice via a subcutaneous osmotic pump with treatment lasting 1 or 4 weeks. Gene expression and immunofluorescence analyses were used to determine chemokine expression and cell recruitment in the skin surrounding the pump outlet. CpGB DNA skin treatment dramatically induced a marked influx of CD11b+ F4/80+ macrophages, increasing over 4 weeks of treatment, and induction of IFNγ and TNFα expression. Chemokines, CCL2, CCL4, CCL5, CXCL9 and CXCL10, were highly induced in CpGB DNA-treated skin, although abrogation of these signalling pathways individually did not alter macrophage accumulation. Flow cytometry analysis showed that TLR9 activation in the skin increased circulating CD11b+ CD115+ Ly6C(hi) inflammatory monocytes following 1 week of CpGB DNA treatment. Additionally, skin-resident CD11b+ cells were found to initially take up subcutaneous CpGB DNA and propagate the subsequent immune response. Using diphtheria toxin-induced monocyte depletion mouse model, gene expression analysis demonstrated that CD11b+ cells are responsible for the CpGB DNA-induced cytokine and chemokine response. Overall, these data demonstrate that chronic TLR9 activation induces a specific inflammatory response, ultimately leading to a striking and selective accumulation of macrophages in the skin.

TLR2 and TLR4 expression in atopic dermatitis, contact dermatitis and psoriasis

The aim of the study was to investigate the expression of Toll-like receptors (TLRs) 2 and 4 on keratinocytes in atopic dermatitis, contact dermatitis, and psoriasis by PCR and by immunohistochemistry including confocal microscopy. Confocal microscopy revealed a granular intra-cellular expression pattern for TLR 2 and a homogenous intra-cellular expression pattern for TLR 4 in normal and diseased skin. TLR 2 was constitutively expressed in the suprabasal layers in normal skin, but limited to the basal epidermis in diseased skin. TLR 4 expression was concentrated to the basal layers in normal skin, whereas it was pronounced in upper layers in diseased skin. The shift in the TLR expression may be related to the disturbed skin barrier and a need for enhanced immune surveillance because of invading microbes. Also, there must be a balance between sufficient immune response and overstimulation.

Membrane and soluble Toll-like receptor 2 in patients with psoriasis treated by Goeckerman therapy

BACKGROUND

Toll-like receptor (TLR) 2 belongs to the large TLR receptor family comprised of at least 10 members with different roles in innate immunity. Psoriasis is recognized as a T-cell driven immune-mediated systemic inflammatory disease with a skin manifestation. An effective therapeutic approach to treat psoriasis is Goeckerman therapy (GT). The aim of this study was to assess both the kinetics of the expression of TLR2 on blood cells and the concentration of soluble (s)TLR2 in serum of patients with psoriasis and to examine the effect of GT on both TLR2 expression and sTLR2 level.

METHODS

Both membrane and sTLR2 were determined in 20 patients and 20 healthy controls. sTLR2 was evaluated by enzyme-linked immunosorbent assay. Flow cytometry method was used to determine the expression of membrane TLR2 of monocytes and granulocytes.

RESULTS

The serum level of sTLR2 was significantly lower (P < 0.0001) in patients both before and after GT compared to the control group. Compared to the membrane expression of TLR2 on monocytes of healthy blood donors, TLR2 expression was significantly higher in patients both before and after GT (P = 0.0001). Similarly, TLR2 expression on granulocytes was significantly higher in patients both before (P = 0.0061) and after (P < 0.0001) therapy than in control.

CONCLUSIONS

Membrane and soluble TLR2 may be involved in the pathogenesis of psoriasis. Both remained unchanged by GT.

Amygdalin analogues inhibit IFN-γ signalling and reduce the inflammatory response in human epidermal keratinocytes

Peptide T (PT), an octapeptide fragment located in the V2 region of the HIV-1 gp120-coating protein, appears to be beneficial in the treatment of psoriasis. Our previous investigations suggest that keratinocytes play a key role in conditioning the therapeutic effects of PT in psoriasis. The aim of this study was to explore the effects of PT and the peptidomimetic natural products, Dhurrin and Prunasin, on the expression of the IL-6, IL-8, IL-23, HSP70 and ICAM-1 on IFN-γ and TNF-α-NHEK activated cells. Moreover, we analysed the interference of PT and its analogues through STAT-3 activation. Our results show that the analogues tested exhibit the beneficial biological effects of PT, suggesting the primary role of keratinocytes upon which PT and the peptidomimetics act directly, by reducing proinflammatory responses. Its reduction appears to be important for therapeutic approach in psoriasis pathogenesis.

Tissue resources for clinical use and marker studies in melanoma

The adequate procurement and preservation of high-quality tissue specimens from patients with melanoma is a critical clinical issue as patients' tumor samples are now used not only for pathological diagnosis but are also necessary to determine the molecular signature of the tumor to stratify patients who may benefit from targeted melanoma therapy. Tissue resources available for physicians and investigators include formalin-fixed paraffin-embedded (FFPE) tissue and frozen tissue, either preserved in optimal cutting temperature (OCT) media or snap frozen. Properly preserved tissue may be used to evaluate melanoma biomarkers by immunohistochemistry (IHC) with tissue microarray (TMA) technology, to perform genetic and genomic analyses, and for other types of translational research in melanoma.

Smoking as a permissive factor of periodontal disease in psoriasis

BACKGROUND

Population-based studies have identified smoking as a pathogenetic factor in chronic periodontitis. At the same time, chronic periodontal disease has also been found to occur more often in persons suffering from psoriasis than in controls with no psoriasis. It is known that smoking aggravates both periodontal disease and psoriasis, but so far it has not been investigated how smoking influences the occurrence and severity of periodontal disease in psoriasis.

METHODS

A hospital-based study was conducted to investigate this question. The study population consisted of 82 psoriasis patients and 89 controls. All patients received a full-mouth periodontal examination, and a published classification based on bleeding on probing, clinical attachment level and probing depth was utilized for staging. Both patients and controls were divided into smoker and non-smoker groups, and the resulting groups were compared in terms of periodontal status. Beyond the descriptive statistics, odds ratios were computed.

RESULTS

Psoriasis in itself increased the likelihood of severe periodontal disease to 4.373 (OR, as compared to non-smoker controls, p<0.05), while smoking increased it to 24.278 (OR, as compared to non-smoker controls, p<0.001) in the studied population. In other words, the risk of severe periodontal disease in psoriasis turned out to be six times higher in smokers than in non-smokers.

CONCLUSIONS

The results of this study corroborate those of other studies regarding the link between psoriasis and periodontal disease, but they also seem to reveal a powerful detrimental effect of smoking on the periodontal health of psoriasis patients, whereby the authors propose that smoking may have a permissive effect on the development of severe periodontal disease in psoriasis.

Study on Certain Biomarkers of Inflammation in Psoriasis Through "OMICS" Platforms

Background:

In recent years, research on psoriasis has focused on the identification of biomarkers for the diagnosis, pathogenesis, prognosis, or therapeutic response of the disease. These studies could provide insights into the susceptibility and natural history of psoriasis. The identification of biomarkers related to comorbidities in psoriasis, such as arthritis, cardiovascular disease, and the metabolic syndrome, is of special clinical interest.

Materials and Methods:

We performed an extensive review on psoriasis biomarkers, including cytokine and growth factors, in the literature published between 1997 and 2013, including cross-references of any retrieved articles. We also included some data from our own studies.

Results:

This review presents current knowledge of soluble biomarkers in psoriasis, including cytokines, chemokines, proangiogenic mediators, growth factors, antimicrobial proteins, neuropeptides, and oxidative stress markers.

Conclusion:

In conclusion, a number of studies have been conducted with the aim of establishing soluble biomarkers for psoriasis. Most of the biomarkers that have been studied do not meet the criteria for a clinically useful biomarker. Further work is needed to establish a role for soluble biomarkers in the diagnosis and treatment of psoriasis, with a special focus on biomarkers for psoriasis comorbidities, such as arthritis, cardiovascular disease, and the metabolic syndrome.

Toll-like receptor 2 activation and comedogenesis: implications for the pathogenesis of acne

BACKGROUND

Acne is a common disorder of the human pilosebaceous unit, yet the mechanisms underlying hyperkeratinisation and subsequent inflammation (comedogenesis) remain to be determined, although cutaneous pathogens are implicated. Previously, it was reported that the release of the cytokine interleukin-1α (IL-1α) by keratinocytes of the sebaceous duct was pivotal in the life cycle of the comedone, mediating both its development and its spontaneous resolution. Toll-like receptors are a family of molecules that recognise pathogen associated molecular patterns (PAMPs) presented by microorganisms, initiating a signalling cascade terminating in the release of antimicrobial compounds and cytokines.

METHODS

We used ex vivo sebaceous gland and primary monolayer keratinocyte culture, alongside ELISAs, immunohistochemistry, Western blotting and RT-PCR to investigate the contribution of TLR activation to acne pathogenesis.

RESULTS

We found TLR2 to be expressed in basal and infundibular keratinocytes, and sebaceous glands, and its activation provoked the release of IL-1α from primary human keratinocytes in vitro. The exposure of microdissected human sebaceous glands to PAMPs specific for TLR2 in vitro resulted in a pattern of IL-1α like cornification after seven days of exposure.

CONCLUSIONS

TLR activation and secretion of IL-1α from keratinocytes may be initiating steps in comedogenesis and, therefore, critical to the pathophysiology of acne.

Expression of antimicrobial peptides and toll-like receptors is increased in tinea and pityriasis versicolor

In superficial tinea and pityriasis versicolor, the causative fungi are for the most part confined to the stratum corneum which is barely reached by leukocytes. Therefore, a role of non-cellular components in the epidermal antifungal defence was suggested. To investigate the presence of such factors in these infections, the expression of human beta defensins 2 and 3 (hBD-2, hBD-3), RNase 7, psoriasin, toll-like receptors 2, 4 and 9 (TLR2, TLR4 and TLR9) and dectin 2 was analysed by use of immunostainings in skin biopsies. We found that hBD2, hBD3, psoriasin, RNase7, TLR2 and TLR4 were significantly more often expressed in distinct layers of lesional epidermis as compared with uninfected epidermis. In both infections but not in normal skin, hBD2 and hBD3 were commonly expressed within the stratum corneum and in the stratum granulosum. Similarly, psoriasin was seen more often in the upper skin layers of both infections as compared with normal skin. No significant differences between normal and infected skin were found for the expression of TLR9 and dectin 2. Our findings clearly show the expression of specific antimicrobial proteins and defence-related ligands in superficial tinea as well as in pityriasis versicolor, suggesting that these factors contribute to fungal containment.

Immunohistochemical expression of heat shock protein 70 in vitiligo

Heat shock proteins (HSPs) are proteins that are expressed under variety of stresses including pathologic conditions. How stresses affect vitiligo is not fully understood and little is known about the role of HSPs generally and Hsp70 specifically in vitiligo. The current study investigated the expression of Hsp70 in vitiliginous (32) and normal skin (10) by immunohistochemistry together with correlating this expression with the clinicopathologic parameters in the studied vitiligo group. Hsp70 was expressed in the cytoplasm of epidermis in all normal skin compared with its localization to the cytoplasm in 35.5% and to the nuclei in 64.5% of epidermis in vitiligo lesions. Intense (P < .001) and diffuse (P < .001) expression of Hsp70 was in favor of vitiligo skin compared with normal skin. Nuclear form of Hsp70 tended to be expressed in progressive forms of the disease. The percentage of Hsp70 expression tended to be decreased with the duration of the disease. From the present study, up-regulation of HSP 70, in the form of its intense and diffuse expression, may be blamed in pathogenesis of vitiligo. Nuclear localization of HSP 70 may be more important than its presence or absence, beside it may be related to progression of the disease.

Heat shock proteins: conditional mediators of inflammation in tumor immunity

Heat shock protein (HSP)-based anticancer vaccines have undergone successful preclinical testing and are now entering clinical trial. Questions still remain, however regarding the immunological properties of HSPs. It is now accepted that many of the HSPs participate in tumor immunity, at least in part by chaperoning tumor antigenic peptides, introducing them into antigen presenting cells such as dendritic cells (DC) that display the antigens on MHC class I molecules on the cell surface and stimulate cytotoxic lymphocytes (CTL). However, in order for activated CD8+ T cells to function as effective CTL and kill tumor cells, additional signals must be induced to obtain a sturdy CTL response. These include the expression of co-stimulatory molecules on the DC surface and inflammatory events that can induce immunogenic cytokine cascades. That such events occur is indicated by the ability of Hsp70 vaccines to induce antitumor immunity and overcome tolerance to tumor antigens such as mucin1. Secondary activation of CTL can be induced by inflammatory signaling through Toll-like receptors and/or by interaction of antigen-activated T helper cells with the APC. We will discuss the role of the inflammatory properties of HSPs in tumor immunity and the potential role of HSPs in activating T helper cells and DC licensing.

Differential expression of TLR-2 and TLR-4 in the epithelial cells in oral lichen planus

OBJECTIVE

Oral lichen planus (OLP) is a chronic inflammatory condition of the mucosa mediated by a complex signalling network between the keratinocytes and the sub-epithelial lymphocytes. Since OLP occurs in constantly renewing epithelium continuously exposed to commensals, we hypothesised that the epithelial cell microflora interactions may mediate the persistent inflammation. By virtue of their ability to respond to most oral commensal microorganisms, the toll like receptor-2 (TLR-2) and TLR-4 are the most widely investigated receptors in oral diseases. The overall objective of this study was to investigate the role of TLR-2 and TLR-4 in OLP.

DESIGN

Systemically healthy OLP and control subjects were recruited after obtaining the institutional review board approval. Expression of TLR-2 and TLR-4 proteins and transcripts in the tissue epithelium and in the epithelial cells isolated from saliva were determined by immunohistochemistry and quantitative real-time polymerase chain reaction respectively.

RESULTS

The tissue epithelium and the salivary epithelial cells expressed reduced TLR-2 and increased TLR-4 proteins and transcripts in OLP. The salivary epithelial cells from OLP subjects secreted elevated IL-12. However, upon stimulation with bacterial lipopolysaccharide the epithelial cells from OLP exhibited a mixed Th1 (IL-12) and Th2 (IL-4) response. Presence of dexamethasone significantly reduced inflammatory cytokines in the in vitro stimulated cultures of salivary epithelial cells from OLP subjects.

CONCLUSION

Collectively, our data support a critical role for the host-microbial interactions in the OLP pathogenesis. The potential use of exfoliated oral epithelial cells in saliva for functional analysis exponentially increases its value as biological specimen for clinical research.

Toll-like receptors in rheumatic diseases: are we paying a high price for our defense against bugs?

In the last decade Toll-like receptor (TLR) research has led to new insights in the pathogenesis of many rheumatic diseases. In autoimmune diseases like systemic lupus erythematosus, rheumatoid arthritis and systemic sclerosis TLR signaling is likely to be involved in tolerance breakthrough and chronic inflammation via combined Fc gamma receptors and TLR recognition of immune complexes. Furthermore, inflammatory diseases like psoriatic arthritis and gout also show more and more evidence for TLR involvement. In this review we will discuss the involvement of TLR signaling in several rheumatic diseases and stress their similarities and differences based on recent findings.

Functions of Toll-like receptors as an inborn immunity component and their participation in the pathogenesis of dermatoses of different etiologies

In addition to serving as a mechanical barrier protecting our organism from the damaging effect of different factors, our skin also takes part in immune reactions developing in case of microbial intervention. Toll-like receptors (TLR) mediating recognition of molecular structures of pathogens are expressed in skin cells of different types initiating the development of adaptive immune reactions when associated with different ligands. The review presents data on the structure and functions of TLR, their localization in skin compartments and their role in the pathogenesis of skin diseases being of infectious etiology and non-infectious origin.

Role of recognizing receptors in the initiation of immune inflammation in theskin of psoriasis patients

The article presents data on the pathogenetic role of Toll-like receptors in the development of immunopathological reactions in the skin. The authors examined the distribution and content of Toll-like receptors TLR2, TLR4 and TLR9 in the affected skin of psoriasis patients. They revealed a statistically significant increase in expression of Toll-like receptors TLR2 and TLR4, which can play an important role for the formation of the inflammatory process involving cells of the adaptive immune system.

Human immunodeficiency virus and leishmaniasis

The Leishmaniases are a group of diseases transmitted to humans by the bite of a sandfly, caused by protozoan parasites of the genus Leishmania. Various Leishmania species infect humans, producing a spectrum of clinical manifestations. It is estimated that 350 million people are at risk, with a global yearly incidence of 1-1.5 million for cutaneous and 500,000 for visceral Leishmaniasis (VL). VL is a major cause of morbidity and mortality in East Africa, Brazil and the Indian subcontinent. Co-infection with human immunodeficiency virus (HIV) alters the immune response to the disease. Here we review the immune response to Leishmania in the setting of HIV co-infection. Improved understanding of the immunology involved in co-infections may help in designing prophylactic and therapeutic strategies against Leishmaniasis.

Toll-like receptors: role in dermatological disease

Toll-like receptors (TLRs) are a class of conserved receptors that recognize pathogen-associated molecular patterns (PAMPs) present in microbes. In humans, at least ten TLRs have been identified, and their recognition targets range from bacterial endotoxins to lipopeptides, DNA, dsRNA, ssRNA, fungal products, and several host factors. Of dermatological interest, these receptors are expressed on several skin cells including keratinocytes, melanocytes, and Langerhans cells. TLRs are essential in identifying microbial products and are known to link the innate and adaptive immune systems. Over the years, there have been significant advances in our understanding of TLRs in skin inflammation, cutaneous malignancies, and defence mechanisms. In this paper, we will describe the association between TLRs and various skin pathologies and discuss proposed TLR therapeutics.

Integrated network analysis of transcriptomic and proteomic data in psoriasis

BACKGROUND

Psoriasis is complex inflammatory skin pathology of autoimmune origin. Several cell types are perturbed in this pathology, and underlying signaling events are complex and still poorly understood.

RESULTS

In order to gain insight into molecular machinery underlying the disease, we conducted a comprehensive meta-analysis of proteomics and transcriptomics of psoriatic lesions from independent studies. Network-based analysis revealed similarities in regulation at both proteomics and transcriptomics level. We identified a group of transcription factors responsible for overexpression of psoriasis genes and a number of previously unknown signaling pathways that may play a role in this process. We also evaluated functional synergy between transcriptomics and proteomics results.

CONCLUSIONS

We developed network-based methodology for integrative analysis of high throughput data sets of different types. Investigation of proteomics and transcriptomics data sets on psoriasis revealed versatility in regulatory machinery underlying pathology and showed complementarities between two levels of cellular organization.