Calcipotriol increases hCAP18 mRNA expression but inhibits extracellular LL37 peptide production in IL-17/IL-22-stimulated normal human epidermal keratinocytes

Evaluation of Dermatological and Neurological Aspects of the Relationship between Rosacea and Headaches

This study aimed to investigate the relationship between rosacea and headaches, focusing on different subtypes, as well as the associated clinical features and triggering factors. In this prospective study, 300 patients diagnosed with rosacea and 320 control subjects without rosacea or any connected mast cell activation illness were included. Patients with rosacea were assessed by a dermatologist according to the 2019 updated rosacea classification (ROSCO panel). Accordingly, patients were classified based on their predominant rosacea subtype as follows: erythematotelangiectatic (ETR), papulopustular (PPR), or phymatous (RhR). Patients experiencing headaches were assessed using the International Headache Classification. Headaches were categorized as migraine, tension-type headaches (TTHs), secondary types (STHs), and cluster-type headaches (CTHs). The ratio of headache was 30.3% in the rosacea group, which did not show a significant difference compared to the control group (30.3% vs. 25.0%, p = 0.138). In 81.3% of rosacea patients with headaches, headache onset occurred after the diagnosis of rosacea. The rate of patients with headaches was higher in the ETR group compared to the PPR and RhR groups (35.2% vs. 16.2% vs. 23.1%, p = 0.007, respectively). In terms of headache subtypes, the rates of patients with migraine and STHs were higher in the ETR group compared to the PPR and RhR groups, while the rate of patients with TTHs was higher in the RhR group. A positive correlation was found between rosacea severity and migraine severity (r = 0.284, p < 0.05). Among the triggering factors for rosacea, only sunlight was found to be associated with headaches. Lower age, female gender, and moderate to severe rosacea severity were identified as independent factors increasing the likelihood of headaches. A significant portion of rosacea patients experience headaches. Particularly, different subtypes of rosacea may be associated with various types of headaches. This study, highlighting the connection between migraine and ETR, is a pioneering work that demonstrates common pathogenic mechanisms and potential triggers.

A Systematic Review of Keratinocyte Secretions: A Regenerative Perspective

Cell regenerative therapy is a modern solution for difficult-to-heal wounds. Keratinocytes, the most common cell type in the skin, are difficult to obtain without the creation of another wound. Stem cell differentiation towards keratinocytes is a challenging process, and it is difficult to reproduce in chemically defined media. Nevertheless, a co-culture of keratinocytes with stem cells usually achieves efficient differentiation. This systematic review aims to identify the secretions of normal human keratinocytes reported in the literature and correlate them with the differentiation process. An online search revealed 338 references, of which 100 met the selection criteria. A total of 80 different keratinocyte secretions were reported, which can be grouped mainly into cytokines, growth factors, and antimicrobial peptides. The growth-factor group mostly affects stem cell differentiation into keratinocytes, especially epidermal growth factor and members of the transforming growth factor family. Nevertheless, the reported secretions reflected the nature of the involved studies, as most of them focused on keratinocyte interaction with inflammation. This review highlights the secretory function of keratinocytes, as well as the need for intense investigation to characterize these secretions and evaluate their regenerative capacities.

A mathematical model to identify optimal combinations of drug targets for dupilumab poor responders in atopic dermatitis

BACKGROUND

Several biologics for atopic dermatitis (AD) have demonstrated good efficacy in clinical trials, but with a substantial proportion of patients being identified as poor responders. This study aims to understand the pathophysiological backgrounds of patient variability in drug response, especially for dupilumab, and to identify promising drug targets in dupilumab poor responders.

METHODS

We conducted model-based meta-analysis of recent clinical trials of AD biologics and developed a mathematical model that reproduces reported clinical efficacies for nine biological drugs (dupilumab, lebrikizumab, tralokinumab, secukinumab, fezakinumab, nemolizumab, tezepelumab, GBR 830, and recombinant interferon-gamma) by describing system-level AD pathogenesis. Using this model, we simulated the clinical efficacy of hypothetical therapies on virtual patients.

RESULTS

Our model reproduced reported time courses of %improved EASI and EASI-75 of the nine drugs. The global sensitivity analysis and model simulation indicated the baseline level of IL-13 could stratify dupilumab good responders. Model simulation on the efficacies of hypothetical therapies revealed that simultaneous inhibition of IL-13 and IL-22 was effective, whereas application of the nine biologic drugs was ineffective, for dupilumab poor responders (EASI-75 at 24 weeks: 21.6% vs. max. 1.9%).

CONCLUSION

Our model identified IL-13 as a potential predictive biomarker to stratify dupilumab good responders, and simultaneous inhibition of IL-13 and IL-22 as a promising drug therapy for dupilumab poor responders. This model will serve as a computational platform for model-informed drug development for precision medicine, as it allows evaluation of the effects of new potential drug targets and the mechanisms behind patient variability in drug response.

Inhibitory effect of timolol on topical glucocorticoid‑induced skin telangiectasia

The aim of the present study wasto investigate the potential inhibitory effect of timolol on topical glucocorticoid-induced skin telangiectasia. In rabbits, flumethasone ointment was used to induce skin telangiectasia in the inner ear. Subsequently, timolol maleate (0.5%) eye drops (TMEDs) were administered twice daily for 4 weeks. Expression of the antibacterial peptides 37-amino acid peptide (LL-37) and kallikrein-5 (KLK5) was detected using quantitative polymerase chain reaction (PCR) and semi-quantitative reverse transcription-PCR. In patients with facial skin telangiectasia, one cheek of each patient was assigned to a treatment group and the other to a control group. For the treatment group cheeks, topical application of TMEDs was combined with 0.1% tacrolimus ointment once or twice daily for 8 weeks. The control group cheeks were administered with 0.1% tacrolimus ointment alone. Alterations in lesions were recorded by dermoscopy, and the L, a and b values of lesions were measured, based on the Commission Internationale de l'Éclairage system, with a chromameter prior to and at 1, 2, 4 and 8 weeks following treatment. The results indicated that erythema, papules and telangiectasia were significantly diminished following 4 weeks of treatment with TMEDs in rabbits. Notably, the expression of LL-37 and KLK5 mRNA was increased in the negative control group; however, it was decreased in the trial and blank groups. Clinical and dermoscopy images demonstrated that erythema was reduced in the 2 groups for 1 week, and that telangiectasia in the treatment group was markedly reduced compared with the control group at 4 weeks. The difference of the L and a values of lesions between the treatment and control group was significant (P<0.05). Overall, the present results suggested that the abnormal expression of LL-37 may be one of the mechanisms underlying the pathogenesis of facial corticosteroid addiction dermatitis (FCAD) and TMEDs may inhibit the mRNA expression of LL-37 by downregulating KLK5; in this regard, TMEDs may serve a role in attenuating telangiectasia, which may be beneficial in improving the telangiectasia symptoms of FCAD.

Human Langerhans Cells with Pro-inflammatory Features Relocate within Psoriasis Lesions

Psoriasis is a common skin disease that presents with well-demarcated patches of inflammation. Recurrent disease in fixed areas of the skin indicates a localized disease memory that is preserved in resolved lesions. In line with such concept, the involvement of tissue-resident immune cells in psoriasis pathology is increasingly appreciated. Langerhans cells (LCs) are perfectly placed to steer resident T cells and local tissue responses in psoriasis. Here, we present an overview of the current knowledge of LCs in human psoriasis, including findings that highlight pro-inflammatory features of LCs in psoriasis lesions. We also review the literature on conflicting data regarding LC localization and functionality in psoriasis. Our review highlights that further studies are needed to elucidate the molecular mechanisms that drive LCs functionality in inflammatory diseases.

The Vitamin D3 analogue calcipotriol suppresses CpG-activated TLR9-MyD88 signalling in murine plasmacytoid dendritic cells

BACKGROUND

Plasmacytoid dendritic cells (pDCs) are involved in the pathogenesis of psoriasis by secreting interferon-α. Vitamin D3 analogues are widely used to treat psoriasis, and the representative analogue calcipotriol (CAL) uniquely downregulates the cytokine production and chemotactic activity of pDCs. However, the molecular mechanism of action of CAL is not well understood.

AIM

To investigate effects of CAL on the Toll-like receptor 9-myeloid differentiation primary response gene 88 (TLR9-MyD88) signalling pathway, which induces cytokine production, in murine pDCs.

METHODS

pDCs were isolated from mouse spleen cells by negative selection or were generated from mouse bone-marrow cells, and were stimulated with CpG-oligodeoxynucleotide (ODN) with or without CAL for 24 h. mRNA expression of TLR9 and MyD88 was assessed by real-time PCR, and the amount of TLR9 was measured by western blotting.

RESULTS

CAL suppressed the CpG-ODN-induced increased expression of MyD88 and TLR9 in pDCs.

CONCLUSIONS

CAL may downregulate pDCs by inhibiting TLR9-MyD88 signalling.

Natural killer cells in inflammatory heart disease

Despite of a multitude of excellent studies, the regulatory role of natural killer (NK) cells in the pathogenesis of inflammatory cardiac disease is greatly underappreciated. Clinical abnormalities in the numbers and functions of NK cells are observed in myocarditis and inflammatory dilated cardiomyopathy (DCMi) as well as in cardiac transplant rejection [1-6]. Because treatment of these disorders remains largely symptomatic in nature, patients have little options for targeted therapies [7,8]. However, blockade of NK cells and their receptors can protect against inflammation and damage in animal models of cardiac injury and inflammation. In these models, NK cells suppress the maturation and trafficking of inflammatory cells, alter the local cytokine and chemokine environments, and induce apoptosis in nearby resident and hematopoietic cells [1,9,10]. This review will dissect each protective mechanism employed by NK cells and explore how their properties might be exploited for their therapeutic potential.

Rosacea: Molecular Mechanisms and Management of a Chronic Cutaneous Inflammatory Condition

Rosacea is a chronic cutaneous inflammatory disease that affects the facial skin. Clinically, rosacea can be categorized into papulopustular, erythematotelangiectatic, ocular, and phymatous rosacea. However, the phenotypic presentations of rosacea are more heterogeneous. Although the pathophysiology of rosacea remains to be elucidated, immunologic alterations and neurovascular dysregulation are thought to have important roles in initiating and strengthening the clinical manifestations of rosacea. In this article, we present the possible molecular mechanisms of rosacea based on recent laboratory and clinical studies. We describe the genetic predisposition for rosacea along with its associated diseases, triggering factors, and suggested management options in detail based on the underlying molecular biology. Understanding the molecular pathomechanisms of rosacea will likely aid toward better comprehending its complex pathogenesis.

Distinctive downmodulation of plasmacytoid dendritic cell functions by vitamin D3 analogue calcipotriol

BACKGROUND

In relation to Th17 cell actions, interferon (IFN)-α production by plasmacytoid dendritic cells (pDCs) are involved in the pathogenesis of psoriasis. Vitamin D3 analogues are widely used in the treatment of psoriasis, however, their actions on pDCs are not well understood.

OBJECTIVE

To investigate the effects of Vitamin D3 analogue calcipotriol (CAL) on pDCs, focusing on the cytokine production and chemotactic activity.

METHODS

We compared in mice the effects of CAL, cyclosporine A (CyA), and triamcinolone acetonide (TA) on the cytokine production by pDCs (IFN-α), conventional DCs (TNF-α), and γd T cells (IL-17A). pDCs isolated from mouse spleen cells were stimulated with CpG-ODN in the presence or absence of each drug for 48h. Purified splenic conventional DCs (cDCs) and lymph node γδ T cells were stimulated with CpG-ODN or with anti-CD3/CD28 antibody, respectively. IFN-α, TNF-α and IL-17A in the 48-h culture supernatants were quantified by ELISA. We also studied the ability of CAL to inhibit the chemotaxis of freshly isolated pDCs toward chemerin and VEGF-A, representative chemoattractants of pDCs, by a real-time monitoring method, EZ-Taxiscan. To assess the effect of CAL on pDC accumulation in vivo, we painted CAL ointment to the mouse skin inflamed by topical application of imiquimod cream (IMQ) for 4 consecutive days. In the skin samples, we enumerated 440c⁺ pDCs by immunohistochemistry and evaluated the mRNA expression of cytokines by real-time PCR.

RESULTS

CAL significantly inhibited CpG-enhanced pDC IFN-α production at a comparable level to T cell IL-17A production, whereas its effect on cDC TNF-α production was minimal. Accordingly, CAL suppressed the CpG-augmented expression of TLR9 and MyD88. On the contrary, CyA strongly suppressed the production of TNF-α and IL-17A, but not IFN-α. TA inhibited the production of all the cytokines tested. The effect of CAL on the chemotactic activity of pDCs was also evaluated, demonstrating a significant downmodulation by exposure to the reagent. CAL depressed chemerin receptor CMKLR1 expression in pDCs. The in vivo mouse study showed that simultaneous application of CAL to the imiquimod-applied skin reduce both the recruitment of pDCs and the expression of IFN-α2 in the skin.

CONCLUSIONS

Our findings suggest that CAL uniquely downmodulates the cytokine production and chemotactic activity of pDCs. The CAL suppression of the in vivo pDC accumulation to the skin suggests that these actions are therapeutically relevant.

IL-22/STAT3-Induced Increases in SLURP1 Expression within Psoriatic Lesions Exerts Antimicrobial Effects against Staphylococcus aureus

BACKGROUND

SLURP1 is the causal gene for Mal de Meleda (MDM), an autosomal recessive skin disorder characterized by diffuse palmoplantar keratoderma and transgressive keratosis. Moreover, although SLURP1 likely serves as an important proliferation/differentiation factor in keratinocytes, the possible relation between SLURP1 and other skin diseases, such as psoriasis and atopic dermatitis, has not been studied, and the pathophysiological control of SLURP1 expression in keratinocytes is largely unknown.

OBJECTIVES

Our aim was to examine the involvement of SLURP1 in the pathophysiology of psoriasis using an imiquimod (IMQ)-induced psoriasis model mice and normal human epidermal keratinocytes (NHEKs).

RESULTS

SLURP1 expression was up-regulated in the skin of IMQ-induced psoriasis model mice. In NHEKs stimulated with the inflammatory cytokines IL-17, IL-22 and TNF-α, which are reportedly expressed in psoriatic lesions, SLURP1 mRNA expression was significantly up-regulated by IL-22 but not the other two cytokines. The stimulatory effect of IL-22 was completely suppressed in NHEKs treated with a STAT3 inhibitor or transfected with siRNA targeting STAT3. Because IL-22 induces production of antimicrobial proteins in epithelial cells, the antibacterial activity of SLURP1 was assessed against Staphylococcus aureus (S. aureus), which is known to be associated with disease severity in psoriasis. SLURP1 significantly suppressed the growth of S. aureus.

CONCLUSIONS

These results indicate SLURP1 participates in pathophysiology of psoriasis by regulating keratinocyte proliferation and differentiation, and by suppressing the growth of S. aureus.

The Vitamin D Analogue Calcipotriol Reduces the Frequency of CD8+ IL-17+ T Cells in Psoriasis Lesions

The vitamin D analogue calcipotriol is an immunomodulatory drug widely used to treat psoriasis; however, how calcipotriol affects the immune cells in psoriasis lesions is not fully understood. The aim of this study was to investigate the effect of calcipotriol on the frequency of CD4(+) and CD8(+) T cells and innate lymphoid cells (ILC) and their production of IL-17A, IFN-γ and IL-22 in psoriasis lesions in patients with chronic plaque psoriasis. Eighteen patients with psoriasis were included, and two similar psoriasis lesions were chosen for each patient. One lesion was treated with calcipotriol (50 μg/g) and the other with vehicle twice a day for 14 days. The clinical effect was measured by degree of erythema, scaling and induration in each lesion (SUM score). Skin biopsies were collected for histological and immunohistochemical analyses. Skin-derived cells were isolated and analysed by flow cytometry. After 14 days of treatment with calcipotriol, a significant clinical and histological effect was seen; however, we found no differences in the frequency of CD4(+) and CD8(+) T cells or ILC between calcipotriol- and vehicle-treated skin. The main finding was a significant decrease in CD8(+) IL-17(+) T cells in skin-derived cells from calcipotriol-treated skin, which was further supported by the absence of CD8(+) IL-17(+) T cells in immunohistochemical staining of calcipotriol-treated skin. No changes in the frequency of IL-22(+) or IFN-γ(+) cells were observed. Our findings show that the vitamin D analogue calcipotriol reduces the frequency of CD8(+) IL-17(+) T cells in psoriasis lesions concomitant with clinical improvement.

Molecular and Morphological Characterization of Inflammatory Infiltrate in Rosacea Reveals Activation of Th1/Th17 Pathways

Rosacea is a common chronic inflammatory skin disease of unknown etiology. Our knowledge about an involvement of the adaptive immune system is very limited. We performed detailed transcriptome analysis, quantitative real-time reverse-transcriptase-PCR, and quantitative immunohistochemistry on facial biopsies of rosacea patients, classified according to their clinical subtype. As controls, we used samples from patients with facial lupus erythematosus and healthy controls. Our study shows significant activation of the immune system in all subtypes of rosacea, characterizing erythematotelangiectatic rosacea (ETR) already as a disease with significant influx of proinflammatory cells. The T-cell response is dominated by Th1/Th17-polarized immune cells, as demonstrated by significant upregulation of IFN-γ or IL-17, for example. Chemokine expression patterns support a Th1/Th17 polarization profile of the T-cell response. Macrophages and mast cells are increased in all three subtypes of rosacea, whereas neutrophils reach a maximum in papulopustular rosacea. Our studies also provide evidence for the activation of plasma cells with significant antibody production already in ETR, followed by a crescendo pattern toward phymatous rosacea. In sum, Th1/Th17 polarized inflammation and macrophage infiltration are an underestimated hallmark in all subtypes of rosacea. Therapies directly targeting the Th1/Th17 pathway are promising candidates in the future treatment of this skin disease.