IL-18 and Cutaneous Inflammatory Diseases. Int J Mol Sci. 2015;16:29357-29369. [PMID: 26690141 PMCID: PMC4691115 DOI: 10.3390/ijms161226172]

Progressive accumulation of hyperinflammatory NKG2Dlow NK cells in early childhood severe atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease that often precedes the development of food allergy, asthma, and allergic rhinitis. The prevailing paradigm holds that a reduced frequency and function of natural killer (NK) cell contributes to AD pathogenesis, yet the underlying mechanisms and contributions of NK cells to allergic comorbidities remain ill-defined. Here, analysis of circulating NK cells in a longitudinal early life cohort of children with AD revealed a progressive accumulation of NK cells with low expression of the activating receptor NKG2D, which was linked to more severe AD and sensitivity to allergens. This was most notable in children co-sensitized to food and aeroallergens, a risk factor for development of asthma. Individual-level longitudinal analysis in a subset of children revealed coincident reduction of NKG2D on NK cells with acquired or persistent sensitization, and this was associated with impaired skin barrier function assessed by transepidermal water loss. Low expression of NKG2D on NK cells was paradoxically associated with depressed cytolytic function but exaggerated release of the proinflammatory cytokine tumor necrosis factor-α. These observations provide important insights into a potential mechanism underlying the development of allergic comorbidity in early life in children with AD, which involves altered NK cell functional responses, and define an endotype of severe AD.

Systemic Inflammatory Proteomic Biomarkers in Atopic Dermatitis: Exploring Potential Indicators for Disease Severity

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory cutaneous disorder, that emerges from intricate interplays among genetic predisposition, immune dysregulation, environmental factors, and compromised skin barrier. Understanding the inflammatory pathway in AD is important due to its fundamental role in the pathogenesis of AD. This study aimed to explore the diverse spectrum of proteins linked to the inflammation of AD and the relationship between systemic biomarkers and clinical severity in AD.

METHODS

We examined the blood samples from 48 patients with AD and 48 healthy controls (HCs) using the Proximity Extension Assay (Olink). Differentially expressed proteins (DEPs) were identified and Pearson correlation analysis was conducted to determine systemic proteomic biomarkers associated with severity of AD.

RESULTS

A total of 29 DEPs were significantly up-regulated and 2 DEPs were significantly down-regulated in AD compared with the HC. The MCP-4, IL-18, MCP-3, TNFRSF9, and IL-17C were the top 5 highest DEPs associated with the severity of AD.

CONCLUSION

Our study sheds light on the intricate network of inflammatory proteins in AD and their potential implications for disease severity. Our results indicate that these systemic inflammatory proteins could be valuable for assessing AD severity and enhancing our understanding of the disease's complexity and its potential management strategies.

Commercial Diagnostics and Emerging Precision Medicine Technologies in Psoriasis and Atopic Dermatitis

While psoriasis and atopic dermatitis (AD) are two common dermatological conditions, their diagnosis and therapeutic decision-making pathways are often complex. As a result, there has been increased focus on the development of precision medicine approaches for psoriasis and AD. Two companies at the forefront of dermatology precision medicine research are Mindera Health and Castle Biosciences. Here, we review the technologies developed by these two companies using a dermal diagnostic patch and superficial skin scrapings, respectively, their research published to date, and their future research goals. Research from both companies shows promise in predicting the response of inflammatory skin disease to biologics using minimally invasive techniques. However, challenges to adoption include insurance coverage and patient trust in the technologies. While there are several differences between Mindera Health and Castle Biosciences, they have a shared goal of utilizing minimally invasive technologies to sample skin and predict response to biologic treatments using a panel of optimized biomarkers.

The evaluation of skin sensitization potential of the UVCB substance diisopentyl phthalate by in silico and in vitro methods

Diisopentyl phthalate (DiPeP) is primarily used as a plasticizer or additive within the production of polyvinyl chloride (PVC), and has many additional industrial applications. Its metabolites were recently found in urinary samples of pregnant women; thus, this substance is of concern as relates to human exposure. Depending upon the nature of the alcohol used in its synthesis, DiPeP may exist either as a mixture consisting of several branched positional isomers, or as a single defined structure. This article investigates the skin sensitization potential and immunomodulatory effects of DiPeP CAS No. 84777-06-0, which is currently marketed and classified as a UVCB substance, by in silico and in vitro methods. Our findings showed an immunomodulatory effect for DiPeP in LPS-induced THP-1 activation assay (increased CD54 expression). In silico predictions using QSAR TOOLBOX 4.5, ToxTree, and VEGA did not identify DiPeP, in the form of a discrete compound, as a skin sensitizer. The keratinocyte activation (Key Event 2 (KE2) of the adverse outcome pathway (AOP) for skin sensitization) was evaluated by two different test methods (HaCaT assay and RHE assay), and results were discordant. While the HaCaT assay showed that DiPeP can activate keratinocytes (increased levels of IL-6, IL-8, IL-1α, and ILA gene expression), in the RHE assay, DiPeP slightly increased IL-6 release. Although inconclusive for KE2, the role of DiPeP in KE3 (dendritic cell activation) was demonstrated by the increased levels of CD54 and IL-8 and TNF-α in THP-1 cells (THP-1 activation assay). Altogether, findings were inconclusive regarding the skin sensitization potential of the UVCB DiPeP-disagreeing with the results of DiPeP in the form of discrete compound (skin sensitizer by the LLNA assay). Additional studies are needed to elucidate the differences between DiPeP isomer forms, and to better understand the applicability domains of non-animal methods in identifying skin sensitization hazards of UVCB substances.

A potential virulence factor: Brucella flagellin FliK does not affect the main biological properties but inhibits the inflammatory response in RAW264.7 cells

The bacterial flagellum is an elongated filament that protrudes from the cell and is responsible for bacterial motility. It can also be a pathogen-associated molecular pattern (PAMP) that regulates the host immune response and is involved in bacterial pathogenicity. In contrast to motile bacteria, the Brucella flagellum does not serve a motile purpose. Instead, it plays a role in regulating Brucella virulence and the host's immune response, similar to other non-motile bacteria. The flagellin protein, FliK, plays a key role in assembly of the flagellum and also as a potential virulence factor involved in the regulation of bacterial virulence and pathogenicity. In this study, we generated a Brucella suis S2 flik gene deletion strain and its complemented strain and found that deletion of the flik gene has no significant effect on the main biological properties of Brucella, but significantly enhanced the inflammatory response induced by Brucella infection of RAW264.7 macrophages. Further experiments demonstrated that the FliK protein was able to inhibit LPS-induced cellular inflammatory responses by down-regulating the expression of MyD88 and NF-κB, and by decreasing p65 phosphorylation in the NF-κB pathway; it also inhibited the expression of NLRP3 and caspase-1 in the NLRP3 inflammasome pathway. In conclusion, our study suggests that Brucella FliK may act as a virulence factor involved in the regulation of Brucella pathogenicity and modulation of the host immune response.

Mendelian Randomization Studies in Atopic Dermatitis: A Systematic Review

Prior studies have found associations between atopic dermatitis (AD) and comorbidities, including depression, obesity, asthma, and allergic rhinitis. Although observational studies often cannot establish robust causality between potential risk factors and AD, Mendelian randomization minimizes confounding when exploring causality by relying on random allelic assortment at birth. In this study, we systematically reviewed 30 Mendelian randomization studies in AD. Body mass index, gut microbial flora, the IL-18 signaling pathway, and gastroesophageal reflux disease were among the causal factors for AD, whereas AD was causal for several medical conditions, including heart failure, rheumatoid arthritis, and conjunctivitis. These insights may improve preventive counseling in AD.

Genetic and Immunological Pathogenesis of Atopic Dermatitis

Type 2 immune-mediated diseases give a clear answer to the issue of nature (genetics) versus nurture (environment). Both genetics and environment play vital complementary roles in the development of atopic dermatitis (AD). As a key component of the atopic march, AD demonstrates the interactive nature of genetic and environmental contributions to atopy. From sequence variants in the epithelial barrier gene encoding FLG to the hygiene hypothesis, AD combines a broad array of contributions into a single syndrome. This review will focus on the genetic contribution to AD and where genetics facilitates the elicitation or enhancement of AD pathogenesis.

Potential Aspects of the Use of Cytokines in Atopic Dermatitis

Atopic dermatitis (AD) is an abnormal inflammatory response in the skin to food, environmental IgE, or non-IgE allergens. This disease belongs to a group of inflammatory diseases that affect both children and adults. In highly developed countries, AD is diagnosed twice as often in children than in adults, which may possibly be connected to increased urbanization. The immune system's pathomechanisms of AD involve humoral mechanisms with IgE, cellular T lymphocytes, dendritic cells occurring in the dermis, Langerhans cells occurring in the epidermis, and other cells infiltrating the site of inflammation (eosinophils, macrophages, mast cells, neutrophils, and basophils). Cytokines are small proteins that affect the interaction and communication between cells. This review characterizes cytokines and potential aspects of the treatment of atopic dermatitis, as well as new strategies that are currently being developed, including targeting cytokines and their receptors.

Single-cell transcriptomics reveals prominent expression of IL-14, IL-18, and IL-32 in psoriasis

RATIONALE

Psoriasis is a chronic inflammatory skin disease involving different cytokines and chemokines.

OBJECTIVES

Here we use single-cell transcriptomic analyses to identify relevant immune cell and nonimmune cell populations for an in-depth characterization of cell types and inflammatory mediators in this disease.

METHODS

Psoriasis skin lesions of eight patients are analyzed using single-cell technology. Data are further validated by in situ hybridization (ISH) of human tissues, serum analyses of human samples and tissues of a murine model of psoriasis, and by in vitro cell culture experiments.

RESULTS

Several different immune-activated cell types with particular cytokine patterns are identified such as keratinocytes, T-helper cells, dendritic cells, macrophages, and fibroblasts. Apart from well-known factors, IL-14 (TXLNA), IL-18, and IL-32 are identified with prominent expression in individual cell types in psoriasis. The percentage of inflammatory cellular subtypes expressing IL-14, IL-18, and IL-32 was significantly higher in psoriatic skin compared with healthy control skin. These findings were confirmed by ISH of human skin samples, in a murine model of psoriasis, in human serum samples, and in in vitro experiments.

CONCLUSIONS

Taken together, we provide a differentiated view of psoriasis immune-cell phenotypes that support the role of IL-14, IL-18, and IL-32 in psoriasis pathogenesis.

Progressive accumulation of hyperinflammatory NKG2D low NK cells in early childhood severe atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease that often precedes the development of food allergy, asthma, and allergic rhinitis. The prevailing paradigm holds that a reduced frequency and function of natural killer (NK) cell contributes to AD pathogenesis, yet the underlying mechanisms and contributions of NK cells to allergic co-morbidities remain ill-defined. Herein, analysis of circulating NK cells in a longitudinal early life cohort of children with AD revealed a progressive accumulation of NK cells with low expression of the activating receptor NKG2D, which was linked to more severe AD and sensitivity to allergens. This was most notable in children co-sensitized to food and aero allergens, a risk factor for development of asthma. Individual-level longitudinal analysis in a subset of children revealed co-incident reduction of NKG2D on NK cells with acquired or persistent sensitization, and this was associated with impaired skin barrier function assessed by transepidermal water loss. Low expression of NKG2D on NK cells was paradoxically associated with depressed cytolytic function but exaggerated release of the proinflammatory cytokine TNF-α. These observations provide important insights into a potential mechanism underlying the development of allergic co-morbidity in early life in children with AD which involves altered NK-cell functional responses, and define an endotype of severe AD.

Challenges and Future Trends in Atopic Dermatitis

Atopic dermatitis represents a complex and multidimensional interaction that represents potential fields of preventive and therapeutic management. In addition to the treatment armamentarium available for atopic dermatitis, novel drugs targeting significant molecular pathways in atopic dermatitis biologics and small molecules are also being developed given the condition's complex pathophysiology. While most of the patients are expecting better efficacy and long-term control, the response to these drugs would still depend on numerous factors such as complex genotype, diverse environmental triggers and microbiome-derived signals, and, most importantly, dynamic immune responses. This review article highlights the challenges and the recently developed pharmacological agents in atopic dermatitis based on the molecular pathogenesis of this condition, creating a specific therapeutic approach toward a more personalized medicine.

Association of IL-4 and IL-18 genetic polymorphisms with atopic dermatitis in Chinese children

Background

Atopic dermatitis (AD) is a common chronic inflammatory skin disease, adversely affecting nearly 20% of the pediatric population worldwide. Interleukin-4 (IL-4) and interleukin-18 (IL-18) are considered to be involved in the pathogenesis and development of AD. The aim of this study was to investigate the association of IL-4 and IL-18 gene polymorphisms with the susceptibility and severity of AD in Chinese children.

Methods

Six candidate single nucleotide polymorphisms (SNPs) in IL-4 and IL-18 genes were genotyped through multi-PCR combined with next-generation sequencing in 132 AD children and 100 healthy controls, and all the analyses were performed on blood genome DNA.

Results

The frequencies of G allele, CG genotype and CG + GG genotype of IL-4 rs2243283, as well as the haplotype IL-4/GTT (rs2243283-rs2243250-rs2243248) were all significantly decreased in AD patients compared with the controls [G vs. C: P = 0.033, OR = 0.59; CG vs. CC: P = 0.024, OR = 0.47; CG + GG vs. CC: P = 0.012, OR = 0.49; GTT vs. CCT: P = 0.011, OR = 0.65]. Moreover, the frequencies of A allele, AA genotype and AG + AA genotype of IL-18 rs7106524, along with the haplotype IL-18/CAA (rs187238-rs360718-rs7106524) were statistically increased in the severe AD patients (A vs. G: P < 0.001, OR = 2.79; AA vs. GG: P = 0.003, OR = 5.51; AG + AA vs. GG: P = 0.036, OR = 2.93; CAA vs. CAG: P = 0.001, OR = 2.86).

Conclusions

Our findings suggested that genetic variation in IL-4 rs2243283 such as G allele, CG genotype and CG + GG genotype might confer the reduced susceptibility to AD in Chinese children. Furthermore, A allele, AA genotype and AG + AA genotype of IL-18 rs7106524 explored the strong association with severity in Chinese AD children.

An integrated in silico-in vitro investigation to assess the skin sensitization potential of 4-Octylphenol

One of the major challenges in chemical toxicity testing is the possibility to protect human health against adverse effects with non-animal methods. In this paper, 4-Octylphenol (OP) was tested for skin sensitization and immunomodulatory effects using an integrated in silico-in vitro test approach. In silico tools (QSAR TOOLBOX 4.5, ToxTree and VEGA) were used together with several in vitro tests including HaCaT cells (quantification of IL-6; IL-8; IL-1α and IL-18 by ELISA and expression of genes TNF, IL1A, IL6 and IL8 by RT- qPCR), RHE model (quantification of IL-6; IL-8; IL-1α and IL-18 by ELISA) and THP-1 activation assay (CD86/CD54 expression and IL-8 release). Additionally, the immunomodulatory effect of OP was investigated using lncRNAs MALAT1 and NEAT1 expression and LPS-induced THP-1 activation (CD86/CD54 expression and IL-8 release). The in silico tools predicted OP as a sensitizer. In vitro tests are also concordant with the in silico prediction. OP increased IL-6 expression (HaCaT cells); IL-18 and IL-8 expressions (RHE model). An irritant potential was also shown by a great expression of IL-1α (RHE model); and increased expression of CD54 marker and IL-8 in THP-1 cells. Immunomodulatory effects of OP were demonstrated by the downregulation of NEAT1, MALAT1 (epigenetic markers), IL6 and IL8; and an increase in LPS-induced CD54 and IL-8 expressions. Overall, results indicate that OP is a skin sensitizer, being positive in three key events of the AOP for skin sensitization, also showing immunomodulatory effects.

The Anti-Atopic Dermatitis Effects of Mentha arvensis Essential Oil Are Involved in the Inhibition of the NLRP3 Inflammasome in DNCB-Challenged Atopic Dermatitis BALB/c Mice

The NLRP3 inflammasome is upregulated by various agents, such as nuclear factor-kappa B (NF-κB), lipopolysaccharide (LPS), and adenosine triphosphate (ATP). The NLRP3 inflammasome facilitations the maturation of interleukin (IL)-1β, a proinflammatory cytokine that is critically involved in the pathogenesis of atopic dermatitis (AD). Although the NLRP3 inflammasome clearly exacerbates AD symptoms such as erythema and pruritus, drugs for AD patients targeting the NLRP3 inflammasome are still lacking. Based on the previous findings that Mentha arvensis essential oil (MAEO) possesses strong anti-inflammatory and anti-AD properties through its inhibition of the ERK/NF-κB signaling pathway, we postulated that MAEO might be capable of modulating the NLRP3 inflammasome in AD. The aim of this research was to investigate whether MAEO affects the inhibition of NLRP3 inflammasome activation in murine bone marrow-derived macrophages (BMDMs) stimulated with LPS + ATP in vitro and in a murine model displaying AD-like symptoms induced by 2,4-dinitrochlorobenzene (DNCB) in vivo. We found that MAEO inhibited the expression of NLRP3 and caspase-1, leading to the suppression of NLRP3 inflammasome activation and IL-1β production in BMDMs stimulated with LPS + ATP. In addition, MAEO exhibited efficacy in ameliorating AD symptoms in a murine model induced by DNCB, as indicated by the reduction in dermatitis score, ear thickness, transepidermal water loss (TEWL), epidermal thickness, and immunoglobulin E (IgE) levels. Furthermore, MAEO attenuated the recruitment of NLRP3-expressing macrophages and NLRP3 inflammasome activation in murine dorsal skin lesions induced by DNCB. Overall, we provide evidence for the anti-AD effects of MAEO via inhibition of NLRP3 inflammasome activation.

Protective assessment of progesterone and its receptor on experimental diabetic neuropathy: Antioxidant and anti-inflammatory effects

Diabetes induces a disorder in mitochondrial activity, which causes damage to the nuclear and mitochondrial DNA and ultimately increases the release of inflammatory cytokines and damages the sciatic nerve and dorsal root ganglion and induces neuropathy. It has been shown that progesterone has anti-inflammatory and antioxidative effects and prevents nerve cell damage. Therefore, the aim of this experiment was to investigate the effect of progesterone receptor neuroprotection on diabetic neuropathy. Forty male Sprague-Dawley rats were divided into four groups, including control group, diabetic control group, diabetic control group + progesterone (30 mg/kg), and diabetic control group + combination of progesterone (30 mg/kg) and RU486 (10 mg/kg). After the induction of diabetes, blood glucose level, body weight, behavioral tests, electrophysiological tests, oxidative and inflammatory factors, and histological parameters were measured. Progesterone treatment significantly reduced the level of sensitivity to hot plate without significant effect on glucose level, and significant changes were also observed in the results of tail flick test. In addition, the results showed that the administration of progesterone can improve MNCV and significantly reduce the serum levels of oxidative stress and inflammatory factors, as well as inflammation and edema around the sciatic nerve. However, RU486 inverted the beneficial effects of progesterone. Progesterone can be considered as a protective agent in reducing DN because of its ability to reduce inflammation and nerve damage. In addition, RU486, a progesterone receptor blocker, inhibits the beneficial effects of progesterone on the DN; thus, progesterone receptors play an important role in the neuroprotective effect of progesterone.

Interleukin-18 and IL-18BP in inflammatory dermatological diseases

Interleukin (IL)-18, an interferon-γ inducer, belongs to the IL-1 family of pleiotropic pro-inflammatory factors, and IL-18 binding protein (IL-18BP) is a native antagonist of IL-18 in vivo, regulating its activity. Moreover, IL-18 exerts an influential function in host innate and adaptive immunity, and IL-18BP has elevated levels of interferon-γ in diverse cells, suggesting that IL-18BP is a negative feedback inhibitor of IL-18-mediated immunity. Similar to IL-1β, the IL-18 cytokine is produced as an indolent precursor that requires further processing into an active cytokine by caspase-1 and mediating downstream signaling pathways through MyD88. IL-18 has been implicated to play a role in psoriasis, atopic dermatitis, rosacea, and bullous pemphigoid in human inflammatory skin diseases. Currently, IL-18BP is less explored in treating inflammatory skin diseases, while IL-18BP is being tested in clinical trials for other diseases. Thereby, IL-18BP is a prospective therapeutic target.

Assessment of selected interleukins (IL-6, IL-17A, IL-18, IL-23) and chemokines (RANTES, IP-10) in children with acute and chronic urticaria

BACKGROUND

Urticarial lesions develop as a result of the activation of mast cells which, through the release of mediators, influence the formation of local inflammatory infiltrates. Changes in the expression of many cytokines and chemokines are observed in the course of urticaria. The aim of the study was to evaluate serum levels of interleukin (IL)-6, IL-17A, IL-18, IL-23, regulated on activation, normal T cell expressed and secreted (RANTES) and interferon (IFN)-γ-inducible protein-10 (IP-10) in children with acute urticaria and exacerbation of chronic urticaria in comparison to healthy volunteers. Moreover, we made an attempt to identify factors associated with the acute phase of urticaria and factors predicting the course of the disease among the studied parameters.

METHODS

We retrospectively analyzed 32 children with acute urticaria and 32 children with chronic urticaria. The control group consisted of 40 healthy children. Each patient was clinically evaluated. Serum concentrations of selected cytokines and chemokines were determined by using enzyme-linked immunosorbent assay.

RESULTS

Patients with acute and chronic urticaria had higher concentrations of IL-6 and IL-17A (p < 0.001) and lower concentrations of IL-18, IL-23, RANTES and IP-10 (p < 0.001) as compared to the control group. A significant association between IL-6 and IP-10 with the acute phase of urticaria has been demonstrated. There was no correlation of the studied cytokines and chemokines with disease activity.

CONCLUSIONS

In children with acute phase of urticaria, the cytokine serum concentration differs compared to healthy subjects. IL-6 and IP-10 seem to be useful in differentiating children with acute phase of urticaria and healthy ones. The search for factors predicting the course of the disease requires further studies.

IL-18BP Improves Early Graft Function and Survival in Lewis-Brown Norway Rat Orthotopic Liver Transplantation Model

Interleukin-18 (IL-18) can effectively activate natural killer (NK) cells and induce large concentrations of interferon-γ (IFN-γ). In healthy humans, IL-18 binding protein (IL-18BP) can inhibit the binding of IL-18 to IL-18R and counteract the biological action of IL-18 due to its high concentration and high affinity, thus preventing the production of IFN-γ and inhibiting NK-cell activation. Through previous studies and the phenomena observed by our group in pig-non-human primates (NHPs) liver transplantation experiments, we proposed that the imbalance in IL-18/IL-18BP expression upon transplantation encourages the activation, proliferation, and cytotoxic effects of NK cells, ultimately causing acute vascular rejection of the graft. In this research, we used Lewis-Brown Norway rat orthotopic liver transplantation (OLTx) as a model of acute vascular rejection. AAV8-Il18bp viral vectors as gene delivery vehicles were constructed for gene therapy to overexpress IL-18BP and alleviate NK-cell rejection of the graft after transplantation. The results showed that livers overexpressing IL-18BP had reduced damage and could function longer after transplantation, effectively improving the survival time of the recipients.

Multiple Cytokine Analysis of Th1/Th2/Th9/Th17/Th22/Treg Cytokine Pathway for Individual Immune Profile Assessment in Patients with Psoriasis

BACKGROUND Psoriasis is an autoimmune and autoinflammatory disorder that has a significant impact on patient quality of life. The aim of the study was to assess the immune profiles of patients with psoriasis with multiple cytokine analysis. MATERIAL AND METHODS Fifty-two male psoriatic patients and 24 healthy male volunteers were recruited. Granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon gamma (IFN-gamma), interleukin (IL)-1 beta, IL-2, Il-4, IL-5, IL-6, IL-9, IL-10, IL-12p70, IL-13, IL-17A, IL-18, IL-21, IL-22, IL-23, IL-27, and tumor necrosis factor (TNF)-alpha were measured in patients' serum with a Th1/Th2/Th9/Th17/Th22/Treg Cytokine 18-Plex Human ProcartaPlex Panel, based on Luminex xMAP technology. RESULTS The median fluorescence intensities of serum GM-CSF, IL-2, IL-5, IL-10, IL-13, IL-17A, IL-21, and IL-22 were not intensive enough to calculate the cytokine concentration. We observed elevated levels of IL-6 (P=0.001) and IL-9 (P=0.003) in patients, compared with the control group. The levels of IL-1beta (P=0.008) and IL-27 (P=0.006) were decreased. In patients with psoriatic arthritis, we noticed a decreased level of IL-9 compared with that in patients without arthritis (P=0.034). The levels of IL-12 (P<0.05) and IL-18 (P<0.05) correlated positively with the Psoriasis Area and Severity Index. We found negative correlations of IL-9 (P<0.05), IL-12 (P<0.05), and IL-23 (P<0.05) with the age of psoriatic patients; IL-12 (P<0.05) and IL-23 (P<0.05) with psoriasis duration; and IL-6 (P<0.05) and IL-9 (P<0.05) with the Nail Psoriasis Severity Index. CONCLUSIONS Multiple cytokine analysis seems to be an important form of individual immune profile assessment before treatment selection.

IL-1 Family Cytokines in Inflammatory Dermatoses: Pathogenetic Role and Potential Therapeutic Implications

The interleukin-1 (IL-1) family is involved in the correct functioning and regulation of the innate immune system, linking innate and adaptative immune responses. This complex family is composed by several cytokines, receptors, and co-receptors, all working in a balanced way to maintain homeostasis. Dysregulation of these processes results in tissue inflammation and is involved in the pathogenesis of common inflammatory dermatoses such as psoriasis, hidradenitis suppurativa, and atopic dermatitis. Therefore, therapeutic targeting of IL-1 pathways has been studied, and several monoclonal antibodies are currently being assessed in clinical trials. So far, promising results have been obtained with anti-IL-36R spesolimab and imsidolimab in pustular psoriasis, and their efficacy is being tested in other conditions.

Expression Profiles of the Ovine IL18 Gene and Association of Its Polymorphism With Hematologic Parameters in Hu Lambs

Hematological traits are important indexes to evaluate health status and immunological conditions in human and livestock. In this study, we measured the hematologic indexes of 819 male Hu lambs and performed the descriptive statistical analysis. The results showed the coefficients of variation of partial indexes were >10%, and the heritability for mean erythrocyte volume (MCV), white blood cell count (WBC), hemoglobin concentration (HGB), hematocrit (HCT), and red blood cell (RBC) distribution-standard deviation (RDW_SD) were medium to high, ranging from 0.17 to 0.43. In addition, Interleukin 18 (IL18), as an important regulator of both innate and acquired immune responses, was selected as candidate gene and subjected to the expression profile analysis, single nucleotide polymorphism (SNP) scanning and association analysis by using quantitative real-time PCR (qRT-PCR), PCR amplification, Sanger sequencing, and KASP genotyping. The results of qRT-PCR indicated that IL18 is predominantly expressed in lymph and lung compared with that in the other tested tissues. In addition, three novel polymorphisms (g. 24991544 A > G, g. 24991651 A > G, and g. 24991749 C > T) were identified in IL18, and the three SNPs were in a strong linkage state. Therefore, only a SNP was genotyped and performed association analysis in the enlarged experimental population, the result of association analysis demonstrated that the polymorphism g. 24991651 A > G was significantly associated with RBC, MCV, MCHC, and RDW_CV. These results will provide the reference values and the novel genetic markers of hematological parameters in sheep.

Granzyme B in Epithelial Barrier Dysfunction and Related Skin Diseases

The predominant function of the skin is to serve as a barrier - to protect against external insults and to prevent water loss. Junctional and structural proteins in the stratum corneum, the outermost layer of the epidermis, are critical to the integrity of the epidermal barrier as it balances ongoing outward migration, differentiation, and desquamation of keratinocytes in the epidermis. As such, epidermal barrier function is highly susceptible to upsurges of proteolytic activity in the stratum corneum and epidermis. Granzyme B is a serine protease scarce in healthy tissues but present at high levels in tissues encumbered by chronic inflammation. Discovered in the 1980s, Granzyme B is currently recognized for its intracellular roles in immune cell-mediated targeted apoptosis as well as extracellular roles in inflammation, chronic injuries, tissue remodeling, and processing of cytokines, matrix proteins, and autoantigens. Increasing evidence has emerged in recent years supporting a role for Granzyme B in promoting barrier dysfunction in the epidermis by direct cleavage of barrier proteins and eliciting immunoreactivity. Likewise, Granzyme B contributes to impaired epithelial function of the airways, retina, gut and vessels. In the present review, the role of Granzyme B in cutaneous epithelial dysfunction is discussed in the context of specific conditions with an overview of underlying mechanisms as well as utility of current experimental and therapeutic inhibitors.

Genetic variants affecting chemical mediated skin immunotoxicity

The skin is an immune-competent organ and this function may be impaired by exposure to chemicals, which may ultimately result in immune-mediated dermal disorders. Interindividual variability to chemical-induced skin immune reactions is associated with intrinsic individual characteristics and their genomes. In the last 30-40 years, several genes influencing susceptibility to skin immune reactions were identified. The aim of this review is to provide information regarding common genetic variations affecting skin immunotoxicity. The polymorphisms selected for this review are related to xenobiotic-metabolizing enzymes (CYPA1 and CYPB1 genes), antioxidant defense (GSTM1, GSTT1, and GSTP1 genes), aryl hydrocarbon receptor signaling pathway (AHR and ARNT genes), skin barrier function transepidermal water loss (FLG, CASP14, and SPINK5 genes), inflammation (TNF, IL10, IL6, IL18, IL31, and TSLP genes), major histocompatibility complex (MHC) and neuroendocrine system peptides (CALCA, TRPV1, ACE genes). These genes present variants associated with skin immune responses and diseases, as well as variants associated with protecting skin immune homeostasis following chemical exposure. The molecular and association studies focusing on these genetic variants may elucidate their functional consequences and contribution in the susceptibility to skin immunotoxicity. Providing information on how genetic variations affect the skin immune system may reduce uncertainties in estimating chemical hazards/risks for human health in the future.

Structural and Functional Changes and Possible Molecular Mechanisms in Aged Skin

Skin aging is a complex process influenced by intrinsic and extrinsic factors. Together, these factors affect the structure and function of the epidermis and dermis. Histologically, aging skin typically shows epidermal atrophy due to decreased cell numbers. The dermis of aged skin shows decreased numbers of mast cells and fibroblasts. Fibroblast senescence contributes to skin aging by secreting a senescence-associated secretory phenotype, which decreases proliferation by impairing the release of essential growth factors and enhancing degradation of the extracellular matrix through activation of matrix metalloproteinases (MMPs). Several molecular mechanisms affect skin aging including telomere shortening, oxidative stress and MMP, cytokines, autophagic control, microRNAs, and the microbiome. Accumulating evidence on the molecular mechanisms of skin aging has provided clinicians with a wide range of therapeutic targets for treating aging skin.

Human β-Defensin 2 and Its Postulated Role in Modulation of the Immune Response

Studies described so far suggest that human β-defensin 2 is an important protein of innate immune response which provides protection for the human organism against invading pathogens of bacterial, viral, fungal, as well as parasitical origin. Its pivotal role in enhancing immunity was proved in infants. It may also be considered a marker of inflammation. Its therapeutic administration has been suggested for maintenance of the balance of systemic homeostasis based on the appropriate composition of the microbiota. It has been suggested that it may be an important therapeutic tool for modulating the response of the immune system in many inflammatory diseases, offering new treatment modalities. For this reason, its properties and role in the human body discussed in this review should be studied in more detail.

Pruritus, Allergy and Autoimmunity: Paving the Way for an Integrated Understanding of Psychodermatological Diseases?

Pruritus is a key symptom in allergology and dermatology, contributing to the global and huge impact on quality of life related to skin disorders, both those which are not related to a primary dermatosis (illness) and those which are linked with primary skin lesions (disease). This is particularly evident within psychophysiological dermatoses, a group of psychodermatological diseases where there is a primary dermatosis, where psychological stress plays a role, and where pruritus may represent a major and shared symptom. The etiopathogenesis of pruritus in those disorders sheds light on the link among psychopathological features, psychological stress and the subtle interface between allergic and autoimmune mechanisms, where mast cells play a pivotal role. Allergy has long been recognised as an altered reactivity to exogenous antigens (allergens), defined as an immediate hypersensitivity mediated by immunoglobulin E (IgE). In turn, the immunological understanding of atopy is related to an immediate hypersensitivity reaction to environmental antigens involving T-helper 2 (Th2) responses and the IgE production. Mast cells are major cells in the early phase of allergy, releasing the mediators involved in the symptoms associated with the allergic disease, including pruritus, when the allergen cross-links with IgE, whose mechanisms can be observed in acute urticaria and atopy. Some allergic reactions may persist and allergy may eventually lead to autoimmunity, with the development of a T-helper 1 (Th1) and then IgE-independent inflammation. For instance, in chronic spontaneous urticaria, the mast cell activation may include autoimmune mechanisms, where autoantibodies against the extracellular α subunit of the high-affinity IgE receptor (FcεRIα) and to IgE are observed, with the involvement of Th1 lymphocytes and the production of interferon-γ (INF-γ). The role of autoimmunity is also suggested in the etiopathogenesis of other psychophysiological dermatoses, namely psoriasis, atopic dermatitis and alopecia areata. In the latter, for example, mast cells were reported to be linked with the loss of immune privilege and they are the key cells involved in the experience of pruritus, whose intensity was reported to precede and be correlated with the onset of the hair loss. Furthermore, considering that the role of hair and skin is wide, from psychosocial aspects (communication and social interaction) to vital functions (such as, temperature control), it is straightforward that they are central in our interactions and synchronization with others and the world; thereby, we may admit that the psychophysiological dermatoses could represent a loss of such synchronization. Furthermore, they are often linked with psychopathology which strongly connects with the concept of desynchronization, namely, sleep disorders and depressive symptoms, the clinical expression of a dysfunction in the interplay among mast cells, pineal gland and melatonin, thus the circadian rhythm, as well as their connection with the hypothalamic corticotrophin-releasing hormone (CRH), well-known for its key role in stress response. Moreover, increasing evidence has supported the existence of cutaneous equivalents for these mechanisms, connecting with those central pathways. Thereby, taking all these concepts into consideration, this review intends to look into the updated evidence on the shared biological mechanisms between allergy and autoimmunity, underlining pruritus as a core element, then revisiting the key role of mast cells and discussing the connection with melatonin and immune-inflammatory pathways in the physiopathology of psychophysiological dermatoses, thus paving the way for the understanding of their psychosomatic correlates and a comprehensive psychodermatological approach.

Association between interleukin gene polymorphisms and susceptibility to gastric cancer in the Qinghai population

OBJECTIVE

To investigate the associations between interleukin (IL) gene polymorphisms and susceptibility to gastric cancer in the Qinghai population, China.

METHODS

Patients with gastric cancer and cancer-free controls were enrolled into the study from Qinghai Provincial People's Hospital between September 2016 and September 2018. Single nucleotide polymorphisms (SNPs) were genotyped with the Sequenom MassARRAY® SNP genotype system. The Hardy-Weinberg equilibrium in allele and genotype frequencies, and general characteristics between patients with gastric cancer and cancer-free controls, were evaluated using χ²-test. Potential associations between interleukin gene variants and the risk of gastric cancer were analysed by logistic regression.

RESULTS

Among eight candidate SNPs, the allele and genotype frequency distribution of IL-1B rs1143634 polymorphism was significantly different between patients with gastric cancer (n = 190) and cancer-free controls (n = 186). The IL-1B rs1143634 GA genotype and IL-1B rs1143634 GA + AA genotype were associated with a reduced risk of gastric cancer, however, the remaining SNPs were not statistically associated with gastric cancer risk in the Qinghai population.

CONCLUSION

The IL-1B rs1143634 polymorphism might be associated with a decreased risk of gastric cancer, and may be a protective factor against gastric cancer.

The Role of Interleukin 10 and 18 in Chronic Spontaneous Urticaria Pathogenesis in the Context of Angioedema Coexistence

Chronic spontaneous urticaria (CSU) is defined using clinical symptoms as spontaneous occurrence of itchy wheals and/or angioedema for at least 6 weeks. Angioedema is underdiagnosed in CSU patients, and its presence has significant negative impact on health-related quality of life, daily activities, health care resource utilization, and work. Various cytokines have been found to be involved in pathogenesis of CSU. To study levels of interleukin (IL)-10 and IL-18 in CSU patients and to look for the differences in CSU subgroups divided with regard to angioedema reoccurrence, we included consecutive CSU patients into the study. To assess disease activity, urticaria activity score was used. In addition, we calculated disease duration time. In all groups, Il-10 and Il-18 serum concentrations were measured. The study involved 52 patients with CSU and 47 healthy volunteers. The IL-10 level was statistically significantly higher in patients with CSU compared to the control group. There were no significant differences in level of IL-18 between those groups. Comparison of patients with CSU and angioedema with those without angioedema showed no significant differences in level of IL-10 and IL-18. We see the need for further studies of serum levels of IL-10 and IL-18 to better understand the pathogenesis of the disease and to find markers useful in predicting the symptom type in the course of CSU.

The interleukin-1 family cytokines in psoriasis: pathogenetic role and therapeutic perspectives

Introduction: IL-1 family cytokines play an important role in the innate immune system and their uncontrolled activation and expression can initiate a pathologic inflammatory response. Their role in psoriasis, pustular psoriasis, and psoriatic arthritis has been studied, and they offer potential interest as therapeutic targets.Areas covered: This review focuses on the role that interleukin (IL)-1 family cytokines play in psoriasis pathogenesis, with a special focus on pustular psoriasis, and how these cytokines can be used as therapeutic targets. Using PubMed, we review the literature for articles related to IL-1 family cytokines and psoriasis, focusing on pustular psoriasis, and including pathogenesis, genetics and therapeutic targets.Expert opinion: IL-1 and IL-36 cytokines act as critical drivers of the autoinflammatory responses involved in pustular psoriasis. Studies on the specific role of each IL-1 cytokine are needed, as well as of their regulatory pathways. Targeting of IL-1 family cytokines has been used in pustular psoriasis, with IL-1 and IL-36 R blockade showing promising results.

NLRP3 Inflammasome at the Interface of Inflammation, Endothelial Dysfunction, and Type 2 Diabetes

Type 2 diabetes mellitus (T2DM), accounting for 90-95% cases of diabetes, is characterized by chronic inflammation. The mechanisms that control inflammation activation in T2DM are largely unexplored. Inflammasomes represent significant sensors mediating innate immune responses. The aim of this work is to present a review of links between the NLRP3 inflammasome, endothelial dysfunction, and T2DM. The NLRP3 inflammasome activates caspase-1, which leads to the maturation of pro-inflammatory cytokines interleukin 1β and interleukin 18. In this review, we characterize the structure and functions of NLRP3 inflammasome as well as the most important mechanisms and molecules engaged in its activation. We present evidence of the importance of the endothelial dysfunction as the first key step to activating the inflammasome, which suggests that suppressing the NLRP3 inflammasome could be a new approach in depletion hyperglycemic toxicity and in averting the onset of vascular complications in T2DM. We also demonstrate reports showing that the expression of a few microRNAs that are also known to be involved in either NLRP3 inflammasome activation or endothelial dysfunction is deregulated in T2DM. Collectively, this evidence suggests that T2DM is an inflammatory disease stimulated by pro-inflammatory cytokines. Finally, studies revealing the role of glucose concentration in the activation of NLRP3 inflammasome are analyzed. The more that is known about inflammasomes, the higher the chances to create new, effective therapies for patients suffering from inflammatory diseases. This may offer potential novel therapeutic perspectives in T2DM prevention and treatment.

Prognostic tools for hypertrophic scar formation based on fundamental differences in systemic immunity

Unpredictable hypertrophic scarring (HS) occurs after approximately 35% of all surgical procedures and causes significant physical and psychological complaints. Parallel to the need to understanding the mechanisms underlying HS formation, a prognostic tool is needed. The objective was to determine whether (systemic) immunological differences exist between patients who develop HS and those who develop normotrophic scars (NS) and to assess whether those differences can be used to identify patients prone to developing HS. A prospective cohort study with NS and HS groups in which (a) cytokine release by peripheral blood mononuclear cells (PBMC) and (b) the irritation threshold (IT) after an irritant (sodium lauryl sulphate) patch test was evaluated. Univariate regression analysis of PBMC cytokine secretion showed that low MCP-1, IL-8, IL-18 and IL-23 levels have a strong correlation with HS (P < .010-0.004; AUC = 0.790-0.883). Notably, combinations of two or three cytokines (TNF-a, MCP-1 and IL-23; AUC: 0.942, Nagelkerke R2 : 0.727) showed an improved AUC indicating a better correlation with HS than single cytokine analysis. These combination models produce good prognostic results over a broad probability range (sensitivity: 93.8%, specificity 86.7%, accuracy 90,25% between probability 0.3 and 0.7). Furthermore, the HS group had a lower IT than the NS group and an accuracy of 68%. In conclusion, very fundamental immunological differences exist between individuals who develop HS and those who do not, whereas the cytokine assay forms the basis of a predictive prognostic test for HS formation, the less invasive, easily performed irritant skin patch test is more accessible for daily practice.

3,3'-Diindolylmethane alleviates acute atopic dermatitis by regulating T cell differentiation in a mouse model

Atopic dermatitis is a severe, chronic relapsing inflammatory disease of the skin with family clustering. It is characterized into acute phase, which is dominated by T helper 2-type immune responses, and chronic phase, which is dominated by T helper 1-type immune responses. Studies have shown that 3,3'-diindolylmethane not only has antitumor effects but also can relieve symptoms of inflammatory diseases by inhibiting the nuclear factor-κB signaling pathway and regulating T cell differentiation. To study the effect of 3,3'-diindolylmethane on atopic dermatitis and the underlying mechanism, a mouse model of acute atopic dermatitis was established using 2,4-dinitrofluorobenzene. After intraperitoneal injection of 3,3'-diindolylmethane, skin erythema and edema in mice were significantly alleviated. Furthermore, 3,3'-diindolylmethane reduced immune activation, probably by inhibiting the secretion of thymic stromal lymphopoietin by keratinocytes. 3,3'-Diindolylmethane also promoted the differentiation of regulatory T cells and inhibited the activation of T helper 2 and T helper 17 cells to reduce atopic dermatitis-related immune responses. However, it showed no significant effect on the differentiation of T helper 1 cells. These results indicate that 3,3'-diindolylmethane has a significant inhibitory effect on T helper 2 cells in the acute phase of atopic dermatitis. Our findings may provide not only more insights into the pathological mechanism of AD, but also a new candidate medicine for it.

TNF Is Partially Required for Cell-Death-Triggered Skin Inflammation upon Acute Loss of cFLIP

cFLIP is required for epidermal integrity and skin inflammation silencing via protection from TNF-induced keratinocyte apoptosis. Here, we generated and analyzed cFLIP epidermal KO mice with additional TNF deficiency. Intriguingly, the ablation of TNF rescued the pathological phenotype of epidermal cFLIP KO from characteristic weight loss and increased mortality. Moreover, the lack of TNF in these animals strongly reduced and delayed the epidermal hyperkeratosis and the increased apoptosis in keratinocytes. Our data demonstrate that TNF signaling in cFLIP-deficient keratinocytes is the critical factor for the regulation of skin inflammation via modulated cytokine and chemokine expression and, thus, the attraction of immune cells. Our data suggest that autocrine TNF loop activation upon cFLIP deletion is dispensable for T cells, but is critical for neutrophil attraction. Our findings provide evidence for a negative regulatory role of cFLIP for TNF-dependent apoptosis and partially for epidermal inflammation. However, alternative signaling pathways may contribute to the development of the dramatic skin disease upon cFLIP deletion. Our data warrant future studies of the regulatory mechanism controlling the development of skin disease upon cFLIP deficiency and the role of cFLIP/TNF in a number of inflammatory skin diseases, including toxic epidermal necrolysis (TEN).

Long-Term and Clinically Relevant Full-Thickness Human Skin Equivalent for Psoriasis

Psoriasis is an incurable, immune-mediated inflammatory disease characterized by the hyperproliferation and abnormal differentiation of keratinocytes. To study in depth the pathogenesis of this disease and possible therapy options suitable, pre-clinical models are required. Three-dimensional skin equivalents are a potential alternative to simplistic monolayer cultures and immunologically different animal models. However, current skin equivalents lack long-term stability, which jeopardizes the possibility to simulate the complex disease-specific phenotype followed by long-term therapeutic treatment. To overcome this limitation, the cell coating technique was used to fabricate full-thickness human skin equivalents (HSEs). This rapid and scaffold-free fabrication method relies on coating cell membranes with nanofilms using layer-by-layer assembly, thereby allowing extended cultivation of HSEs up to 49 days. The advantage in time is exploited to develop a model that not only forms a disease phenotype but can also be used to monitor the effects of topical or systemic treatment. To generate a psoriatic phenotype, the HSEs were stimulated with recombinant human interleukin 17A (rhIL-17A). This was followed by systemic treatment of the HSEs with the anti-IL-17A antibody secukinumab in the presence of rhIL-17A. Microarray and RT-PCR analysis demonstrated that HSEs treated with rhIL-17A showed downregulation of differentiation markers and upregulation of chemokines and cytokines, while treatment with anti-IL-17A antibody reverted these gene regulations. Gene ontology analysis revealed the proinflammatory and chemotactic effects of rhIL-17A on the established HSEs. These data demonstrated, at the molecular level, the effects of anti-IL-17A antibody on rhIL-17A-induced gene regulations. This shows the physiological relevance of the developed HSE and opens venues for its use as an alternative to ex vivo skin explants and animal testing.

Review of Prominent Cytokines as Superior Therapeutic Targets for Moderate-to-Severe Atopic Dermatitis

Cytokines predominate the inflammatory pathways in diseases like rhinitis, asthma, and atopic dermatitis. Corticosteroids and immunosuppressants are presently the mainstays of treatment for patients with moderate-to-severe disease, but often accompany a poor side effect profile. In this review, we attempt to consolidate current data on various interleukins (IL) that participate in the pathogenesis of atopic dermatitis (AD) to further improve therapeutic strategies. For now, dupilumab is the most accepted biologic to be registered for treatment for moderate-to-severe disease. Recently, IL-37, IL-13, IL-26, IL-17 & IL-31/33 axis as well as proteins like thymic stromal lymphopoietin (TSLP) show promising results as future therapeutic targets because of their important role in the pathogenesis of AD. However, further studies are required to clarify the safety and efficacy of these interventions compared to current treatment modalities but it is worthwhile to pursue research into biologics as a more successful treatment option for moderate-to-severe AD.

IL-18 in Blood Serum of Hepatitis C Patients Might be of Predictive Value for Individual Outcomes

OBJECTIVE

Pro- inflammatory cytokines including Interleukin (IL)-18 have been shown to be involved in the clearance of Hepatitis C virus (HCV) infection. However, changes in the balance of pro- and anti-inflammatory cytokines production during the immune response, can elicit a variety of liver damages. Therefore, it is of interest to study IL-18 serum levels in hepatitis patients and its correlation with HCV infection.

METHODS

Twenty-nine newly diagnosed HCV+ patients with no history of antiviral therapy, and 17 healthy controls, were enrolled in our study. Biochemical markers of liver disease were evaluated by biochemistry assay kits. Serum concentrations of IL-18 were determined with the ELISA method before and after treatment with pangenotypic direct-acting antivirals (DAAs) treatment.

RESULTS

Our results showed statistically significant difference in serum levels of IL-18 in HCV+ patients (692.261 ± 48.76) compared to healthy controls (520.00 ± 44.73) (P=0.021). However, there was no significant difference in IL-18 serum levels between the treated group compared to untreated patients (P=0.74). No significant correlations were detected between the level of IL-18 and liver enzyme levels.

CONCLUSION

According to our study, IL-18 might be a disease marker associated with HCV infection; however, this conclusion requires further investigation.

Dynamical modeling of pro- and anti-inflammatory cytokines in the early stage of septic shock

A dynamical model of the pathophysiological behaviors of IL18 and IL10 cytokines with their receptors is tested against data for the case of early sepsis. The proposed approach considers the surroundings (organs and bone marrow) and the different subsystems (cells and cyctokines). The interactions between blood cells, cytokines and the surroundings are described via mass balances. Cytokines are adsorbed onto associated receptors at the cell surface. The adsorption is described by the Langmuir model and gives rise to the production of more cytokines and associated receptors inside the cell. The quantities of pro and anti-inflammatory cytokines present in the body are combined to give global information via an inflammation level function which describes the patient’s state. Data for parameter estimation comes from the Sepsis 48 H database. Comparisons between patient data and simulations are presented and are in good agreement. For the IL18/IL10 cytokine pair, 5 key parameters have been found. They are linked to pro-inflammatory IL18 cytokine and show that the early sepsis is driven by components of inflammatory character.

Regulation of Human Innate Lymphoid Cells in the Context of Mucosal Inflammation

Since their identification as a unique cell population, innate lymphoid cells (ILCs) have revolutionized our understanding of immune responses, leaving their impact on multiple inflammatory and fibrotic pathologies without doubt. Thus, a tightly controlled regulation of local ILC numbers and their activity is of crucial importance. Even though this has been extensively studied in murine ILCs in the last few years, our knowledge of human ILCs is still lagging behind. Our review article will therefore summarize recent insights into the function of human ILCs and will particularly focus on their regulation under inflammatory conditions. The quality and intensity of ILC involvement into local immune responses at mucosal sites of the human body can potentially be modulated via three different axes: (1) activation of tissue-resident mature ILCs, (2) plasticity and local transdifferentiation of specific ILC subsets, and (3) tissue migration and accumulation of peripheral ILCs. Despite a still ongoing scientific effort in this field, already existing data on the fate of human ILCs under different pathologic conditions clearly indicate that all three of these mechanisms are of relevance for the clinical course of chronic inflammatory and autoimmune diseases and might likewise provide new target structures for future therapeutic strategies.

IL-1 family and Cutaneous Leishmaniasis: A poorly understood relationship

The cytokines of the interleukin (IL) -1 family act in the initiation of an effective immune response in Leishmania infection, represented mainly by the T helper 1 (Th1) profile, in addition to being associated with disease exacerbation and controversial contributions in the Th2 responses. The family also includes members who self-regulate inflammation, such as antagonists and anti-inflammatory cytokines, most of which have not yet been studied in Cutaneous Leishmaniasis (CL) in humans. Here we summarize findings about what is known so far about the role of these cytokines in mice, the main study model, and in humans. We reinforce the importance of studies of these cytokines as new targets in the context of CL.

ATP-P2X7-Induced Inflammasome Activation Contributes to Melanocyte Death and CD8+ T-Cell Trafficking to the Skin in Vitiligo

Extracellular adenosine 5'-triphosphate (ATP) is a well-known inflammasome-activating signal. Emerging evidence demonstrates a critical role for inflammasome activation in vitiligo pathogenesis. However, the specific molecular mechanism of inflammasome-dependent melanocyte degeneration in vitiligo is still not clear. This study presents how extracellular ATP, released from keratinocytes by oxidative stress, affects melanocyte survival in vitiligo skin. H₂O₂-induced oxidative injury increased ATP release from keratinocytes and skin tissues. The high concentration of extracellular ATP induced both ROS production and cell death in melanocytes. Treatment with ATP caused the activation of caspase-1 as well as the production of active forms of IL-1β and IL-18 via P2X7 receptor in keratinocytes and melanocytes. Lesional and perilesional skin of vitiligo showed higher levels of ATP as well as upregulation of active caspase-1 compared with nonlesional skin, suggesting its possible role in inflammasome activation in vitiligo. Moreover, the elevated expression of CXCL9 in keratinocytes, mediated through ATP/P2X7 receptor-dependent inflammasome activation, was responsible for CLA⁺CD8⁺ T-cell chemotaxis into the skin. These results demonstrate that extracellular ATP as a danger signal activates the inflammasome pathway and increases cutaneous chemotaxis of CD8⁺ T cells via CXCL9 in vitiligo. Therefore, targeting ATP-P2X7 signaling may be a potential strategy for vitiligo treatment.

A comprehensive pathway map of IL-18-mediated signalling

Interleukin-18 (IL-18) is a member of the IL-1 family of cytokines and was initially described as an IFN-γ-inducing factor derived from anti-CD3-stimulated T-helper (Th)1 cells. IL-18 plays a significant role in the activation of hematopoietic cell types mediating both Th1 and Th2 responses and is the primary inducer of interferon-γ in these cells. The biological activity of IL-18 is mediated through its binding to the IL-18 receptor complex and activation of nuclear factor-κB (NF-κB), culminating in the production and release of several cytokines, chemokines, and cellular adhesion molecules. In certain cell types, IL-18 also activates mitogen-activated protein kinases (MAPKs) and phosphoinositide 3-kinase/ AKT serine/threonine kinase (PI3K/AKT) signaling modules leading to the production and release of proinflammatory cytokines. IL-18-mediated signaling acts as one of the vital components of the immunomodulatory cytokine networks involved in host defense, inflammation, and tissue regeneration. Albeit its biomedical importance, a comprehensive resource of IL-18 mediated signaling pathway is currently lacking. In this study, we report on the development of an integrated pathway map of IL-18/IL-18R signaling. The pathway map was developed through literature mining from published literature based on manual curation guidelines adapted from NetPath and includes information on 16 protein-protein interaction events, 38 enzyme-catalysis events, 12 protein translocation events, 26 activations/inhibition events, transcriptional regulators, 230 gene regulation events and 84 induced protein expression events. The IL-18 signaling pathway can be freely accessed through the WikiPathways database (https://www.wikipathways.org/index.php/Pathway:WP4754).

Omnipresence of inflammasome activities in inflammatory bone diseases

The inflammasomes are intracellular protein complexes that are assembled in response to a variety of perturbations including infections and injuries. Failure of the inflammasomes to rapidly clear the insults or restore tissue homeostasis can result in chronic inflammation. Recurring inflammation is also provoked by mutations that cause the constitutive assembly of the components of these protein platforms. Evidence suggests that chronic inflammation is a shared mechanism in bone loss associated with aging, dysregulated metabolism, autoinflammatory, and autoimmune diseases. Mechanistically, inflammatory mediators promote bone resorption while suppressing bone formation, an imbalance which over time leads to bone loss and increased fracture risk. Thus, while acute inflammation is important for the maintenance of bone integrity, its chronic state damages this tissue. In this review, we discuss the role of the inflammasomes in inflammation-induced osteolysis.

Polyphenol mixture of a native Korean variety of Artemisia argyi H. (Seomae mugwort) and its anti‑inflammatory effects

In the present study, a polyphenolic mixture was isolated from Seomae mugwort (SM; a native Korean variety of Artemisia argyi H.) via extraction with aqueous 70% methanol followed by the elution of ethyl acetate over a silica gel column. Each polyphenolic compound was analyzed using high-performance liquid chromatography coupled with tandem mass spectrometry, and compared with the literature. In addition to the 14 characterized components, one hydroxy-cinnamate, six flavonoids, and one lignan were reported for the first time, to the best our knowledge, in Artemisia argyi H. The anti-inflammatory properties of SM polyphenols were studied in lipopolysaccharide-treated RAW 264.7 macrophage cells. The SM polyphenols attenuated the activation of macrophages via the inhibition of nitric oxide production, nuclear factor-κB activation, the mRNA expression of inducible nitric oxide synthase, tumor necrosis factor α and interleukin-1β, and the phosphorylation of mitogen-activated protein kinase. Our results suggested that SM polyphenols may have therapeutic potential for the treatment of inflammatory-related diseases.

Serum levels of selected cytokines [interleukin (IL)-17A, IL-18, IL-23] and chemokines (RANTES, IP10) in the acute phase of immunoglobulin A vasculitis in children

The pathogenesis of the immunoglobulin A vasculitis (IgAV) is still unknown. The available data shows that interleukin (IL)-17, IL-18, IL-23, regulated on activation, normal T cell expressed and secreted (CCL 5, RANTES), and interferon (IFN)-γ-inducible protein 10 (IP10) participate in the pathogenesis of IgAV by influencing the recruitment of leukocytes to the site of inflammation. The aim of this study was to analyze the serum concentration of IL-17A, IL-18, IL-23, RANTES, and IP10 in patients with acute IgAV compared to healthy children. Moreover, we wanted to assess the suitability of the levels of tested cytokines to predict the severity of the disease. All children with IgAV hospitalized in our institution between 2012 and 2017 were included in the study. Cytokines levels were determined in a serum sample secured at admission to the hospital. Basic laboratory tests have also been analyzed. IL-17A, IL-18, and IL-23 were significantly higher in whole IgAV group (52.25 pg/ml; 164.1 pg/ml and 700 pg/ml, respectively) than in the control group (27.92 pg/ml; 140.1 pg/ml and 581.5 pg/ml, respectively). The receiver operating characteristic (ROC) curve analysis revealed the largest area under the curve (AUC 0.979, p < 0.001) for the IL-17A with 95.1% sensitivity and 91.7% specificity. There were no significant differences in cytokine levels depending on the severity of the IgAV. Although the serum levels of the IL-17A, IL-18, and IL-23 increase significantly in the acute phase of the IgAV, they cannot be used as indicators of predicting the course of the disease. IL-17A seems to be a good predictor of IgAV occurrences.

Use of Natural Components Derived from Oil Seed Plants for Treatment of Inflammatory Skin Diseases

The incidence of inflammatory skin diseases is increasing, so the search for relevant therapeutics is of major concern. Plants are rich in phytochemicals which can alleviate many symptoms. In this review, we concentrate on compounds found in the seeds of widely cultivated plants, regularly used for oil production. The oils from these plants are often used to alleviate the symptoms of inflammatory diseases through synergetic action of unsaturated fatty acids and other phytochemicals most commonly derived from the terpenoid pathway. The knowledge of the chemical composition of oil seeds and the understanding of the mechanisms of action of single components should allow for a more tailored approach for the treatment for many diseases. In many cases, these seeds could serve as an efficient material for the isolation of pure phytochemicals. Here we present the content of phytochemicals, assumed to be responsible for healing properties of plant oils in a widely cultivated oil seed plants and review the proposed mechanism of action for fatty acids, selected mono-, sesqui-, di- and triterpenes, carotenoids, tocopherol and polyphenols.

Interleukin-18 exacerbates skin inflammation and affects microabscesses and scale formation in a mouse model of imiquimod-induced psoriasis

Background:

As a potent pro-inflammatory cytokine of the interleukin (IL)-1 family, IL-18 was elevated in early active and progressive plaque-type psoriatic lesions and that serum or plasma levels of IL-18 correlated with the Psoriasis Area and Severity Index (PASI). Although results from previous studies have established that IL-18 may aggravate psoriatic inflammation, the mechanisms of this process remain unknown. In this study, IL-18 knock out (KO) mice and wild-type (WT) mice were used to investigate the effects of IL-18 within a mouse model of psoriasis.

Methods:

WT and IL-18 KO mice were divided into four groups, including imiquimod (IMQ)-treated IL-18 KO group (n = 11) and WT group (n = 13) as well as their respectively gene-matched control mice (receiving vaseline; n = 12). PASI scores were used to evaluate psoriatic lesions in IMQ-treated mice. Pathological features and dermal cellular infiltration were investigated by hematoxylin and eosin staining. The levels of psoriasis-related cytokines including IL-23, IL-17, IL-12, IL-1β, IFNγ, IL-15, IL-27, and IL-4 were tested by real-time polymerase chain reaction (PCR). The protein level of IL-1β, IL-27, CXCL1, and Ly6 g were investigated by immunohistochemistry (IHC).

Results:

Acanthosis (98.46 ± 14.12 vs. 222.68 ± 71.10 μm, P < 0.01) and dermal cell infiltration (572.25 ± 47.45 vs. 762.47 ± 59.59 cells/field, P < 0.01) were significantly milder in IMQ-induced IL-18 KO mice compared with that in WT mice. IMQ-induced IL-18 KO mice manifested larger areas of Munro microabscesses (11,467.83 ± 5112.09 vs. 4093.19 ± 2591.88 μm², P < 0.01) and scales (100,935.24 ± 41,167.77 vs. 41,604.41 ± 14,184.10 μm², P < 0.01) as compared with WT mice. In skin lesions of IL-18 KO mice, the expressions of IL-1β, IL-4, and IL-27 were all significantly upregulated but IL-17 was decreased. Histologically, strong positive signals of Ly6g were observed within the epidermis of IL-18 KO mice but expressions of CXCL1 were decreased.

Conclusions:

IL-18 may exacerbate prominent inflammation and influence pathological features in IMQ-induced mouse model of psoriasis. IL-18 may upregulate pro-inflammatory cytokines and reduce protective cytokines, thus aggravating psoriatic inflammation. In addition, IL-18 may be involved in the formation of Munro microabscesses and scales.

Cell death-mediated cytokine release and its therapeutic implications

Targeting apoptosis to treat diseases has seen tremendous success over the past decades. More recently, alternative forms of regulated cell death, including pyroptosis and necroptosis, have been described. Understanding the molecular cascades regulating both pyroptosis and necroptosis will yield even more targets to treat diseases. These lytic forms of cell death are distinct from apoptosis due to their characteristic lysis and release of cellular components that promote disease or direct a beneficial immune response. In this review, we focus on how pyroptosis and necroptosis, which release potent immune cytokines such as IL-1 and IL-18, contribute to various diseases. We also consider the important role that the executioners of these cell death pathways, GSDMD and MLKL, play in the progression of inflammatory diseases. Crosstalk between the different cell death pathways likely plays a major role physiologically. New therapeutic strategies targeting these specific molecules hold enormous potential for managing inflammatory diseases.