IL-36γ has proinflammatory effects on human endothelial cells

Epidermal proteomics demonstrates Elafin as a psoriasis-specific biomarker and highlights increased anti-inflammatory activity around psoriatic plaques

BACKGROUND

Eczema and psoriasis are common diseases. Despite both showing active epidermal contribution to the inflammatory process, their molecular aetiology and pathological mechanisms are different.

OBJECTIVE

Further molecular insight into these differences is therefore needed to enable effective future diagnostic and treatment strategies. The majority of our mechanistic and clinical understanding of psoriasis and eczema is derived from RNA, immunohistology and whole skin biopsy data.

METHODS

In this study, non-invasive epidermal sampling of lesional, perilesional and non-lesional skin from diseased and healthy skin was used to perform an in depth proteomic analysis of epidermal proteins.

RESULTS

Our findings confirmed the psoriasis-associated cytokine IL-36γ as an excellent protein biomarker for lesional psoriasis. However, ELISA and ROC curve analysis of 53 psoriasis and 42 eczema derived samples showed that the sensitivity and specificity were outperformed by elastase-specific protease inhibitor, elafin. Of note, elafin was also found upregulated in non-lesional psoriatic skin at non-predilection sites demonstrating inherent differences between the non-involved skin of healthy and psoriatic individuals. Mass spectrometry and ELISA analysis also demonstrated the upregulation of the anti-inflammatory molecule IL-37 in psoriatic perilesional but not lesional skin. The high expression of IL-37 surrounding psoriatic plaque may contribute to the sharp demarcation of inflammatory morphology changes observed in psoriasis. This finding was also specific for psoriasis and not seen in atopic dermatitis or autoimmune blistering perilesional skin. Our results confirm IL-36γ and add elafin as robust, hallmark molecules distinguishing psoriasis and eczema-associated inflammation even in patients under systemic treatment.

CONCLUSIONS

Overall, these findings highlight the potential of epidermal non-invasive sampling and proteomic analysis to increase our diagnostic and pathophysiologic understanding of skin diseases. Moreover, the identification of molecular differences in healthy-looking skin between patients and healthy controls highlights potential disease susceptibility markers and proteins involved in the initial stages of disease.

Understanding the impact of risankizumab on keratinocyte-derived IL-23A in a novel organotypic 3D skin model containing IL-23A responsive and IL-17A producing γδ-T-cells

PURPOSE

To study the effects of the anti-IL-23A antibody risankizumab on the IL-36γ/IL-23A/IL-17A signalling cascade we used a newly developed 3D skin model consisting of primary human keratinocytes, fibroblasts and γδ-T-cells.

METHODS

In this in vitro study we developed new full-thickness 3D skin models containing normal human epidermal keratinocytes (NHEK), normal human dermal fibroblasts (NHDF) and IL-23A responsive and IL-17A producing γδ-T-cells. The effects of IL-36γ stimulation with and without risankizumab treatment on IL-23A and IL-17A expression were examined at the RNA and protein levels.

RESULTS

In preliminary monolayer experiments stimulation of γδ-T-cells with IL-23A promoted the IL-17A expression that was inhibited after risankizumab treatment. Using 3D skin models containing γδ-T-cells, we found that stimulation with IL-36γ significantly increased not only IL-23A but also IL-17A expression. These effects were inhibited by concomitant treatment with risankizumab.

CONCLUSIONS

Our results showed that blockade of IL-23A has inhibitory effects on the IL-36γ/IL-23A feedforward loop. Our newly developed 3D skin model containing IL-23A responsive and IL-17A producing γδ-T-cells enables molecular analysis of targeted therapies aimed at the IL-36γ/IL-23A/IL-17A signalling cascade in psoriasis.

The role of interleukin-36 in health and disease states

The interleukin (IL)-1 superfamily upregulates immune responses and maintains homeostasis between the innate and adaptive immune systems. Within the IL-1 superfamily, IL-36 plays a pivotal role in both innate and adaptive immune responses. Of the four IL-36 isoforms, three have agonist activity (IL-36α, IL-36β, IL-36γ) and the fourth has antagonist activity (IL-36 receptor antagonist [IL-36Ra]). All IL-36 isoforms bind to the IL-36 receptor (IL-36R). Binding of IL-36α/β/γ to the IL-36R recruits the IL-1 receptor accessory protein (IL-1RAcP) and activates downstream signalling pathways mediated by nuclear transcription factor kappa B and mitogen-activated protein kinase signalling pathways. Antagonist binding of IL-36Ra to IL-36R inhibits recruitment of IL-1RAcP, blocking downstream signalling pathways. Changes in the balance within the IL-36 cytokine family can lead to uncontrolled inflammatory responses throughout the body. As such, IL-36 has been implicated in numerous inflammatory diseases, notably a type of pustular psoriasis called generalized pustular psoriasis (GPP), a chronic, rare, potentially life-threatening, multisystemic skin disease characterised by recurrent fever and extensive sterile pustules. In GPP, IL-36 is central to disease pathogenesis, and the prevention of IL-36-mediated signalling can improve clinical outcomes. In this review, we summarize the literature describing the biological functions of the IL-36 pathway. We also consider the evidence for uncontrolled activation of the IL-36 pathway in a wide range of skin (e.g., plaque psoriasis, pustular psoriasis, hidradenitis suppurativa, acne, Netherton syndrome, atopic dermatitis and pyoderma gangrenosum), lung (e.g., idiopathic pulmonary fibrosis), gut (e.g., intestinal fibrosis, inflammatory bowel disease and Hirschsprung's disease), kidney (e.g., renal tubulointerstitial lesions) and infectious diseases caused by a variety of pathogens (e.g., COVID-19; Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus pneumoniae infections), as well as in cancer. We also consider how targeting the IL-36 signalling pathway could be used in treating inflammatory disease states.

Effects on peripheral and central nervous system of key inflammatory intercellular signalling peptides and proteins in psoriasis

Psoriasis is a chronic systemic inflammatory cutaneous disease. Where the immune system plays an important role in its pathogenesis, with key inflammatory intercellular signalling peptides and proteins including IL-17 and IL-23. The psychoneurological system also figures prominently in development of psoriasis. There is a high prevalence of comorbidity between psoriasis and mental health disorders such as depression, anxiety and mania. Patients with psoriasis often suffer from pathological pain in the lesions, and their neurological accidents could improve the lesions in innervated areas. The immune system and the psychoneurological system interact closely in the pathogenesis of psoriasis. Patients with psoriasis exhibit abnormal levels of neuropeptides both in circulating and localized lesion, acting as immunomodulators involved in the inflammatory response. Moreover, receptors for inflammatory factors are expressed in both peripheral and central nervous systems (CNSs), suggesting that nervous system can receive and be influenced by signals from immune system. Key inflammatory intercellular signalling peptides and proteins in psoriasis, such as IL-17 and IL-23, can be involved in sensory signalling and may affect synaptic plasticity and the blood-brain barrier of CNS through the circulation. This review provides an overview of the multiple effects on the peripheral and CNS under conditions of systemic inflammation in psoriasis, providing a framework and inspiration for in-depth studies of neuroimmunomodulation in psoriasis.

Interleukin-38: A crucial player in periodontitis

BACKGROUND

The objective of this study was to compare the levels of gingival crevicular fluid (GCF), salivary, and serum matrix metalloproteinase-9, interleukin (IL)-17, IL-36γ, and IL-38 in individuals with healthy periodontium, gingivitis, and periodontitis and to evaluate their correlations with clinical periodontal parameters.

MATERIALS AND METHODS

Ninety systemically healthy and nonsmoking volunteers divided into a healthy (H) group (n = 30), a gingivitis (G) group (n = 30), and a periodontitis (P) group (n = 30) were included in this study. Clinical periodontal parameters of volunteers were recorded, and GCF, unstimulated saliva, and serum samples were collected. Data analysis was done with enzyme-linked immunosorbent assays. The Kruskal-Wallis test and Bonferroni correction were used for multiple comparisons and post hoc statistical analyses.

RESULTS

The group H had significantly lower clinical parameters than the group P (p < 0.001). GCF and salivary IL-36γ and IL-38 levels were significantly higher in the group P than in the H and G groups (p < 0.05). Positive correlations between biochemical findings and clinical periodontal parameters were observed.

CONCLUSIONS

IL-36γ and IL-38 levels in GCF, saliva, and serum correlate with clinical periodontal parameters and may play a role in determining the activity of periodontitis.

Endothelial Dysfunction in Psoriasis: An Integrative Review

Vascular endothelial cells (ECs), the inner layer of blood vessels, were previously considered to be a passive lining that facilitates cellular and molecular exchange. However, recent studies have revealed that ECs can respond to various stimuli and actively regulate vascular function and skin inflammation. Specific subtypes of ECs are known to have significant roles in a diverse range of physiological and pathological processes in the skin. This review suggests that EC dysfunction is both causal and consequential in the pathogenesis of psoriasis. Further investigations into dysregulated pathways in EC dysfunction may provide new insights for the treatment of psoriasis.

Emerging Role of the IL-36/IL-36R Axis in Multiple Inflammatory Skin Diseases

IL-36 is a most recent member of the IL-1 cytokine family, primarily expressed at barrier sites of the body such as the skin, lungs, and intestine. It plays a vital role in inflammation and is implicated in the development of various cutaneous; intestinal; and pulmonary disorders, including psoriasis, inflammatory bowel disease, and chronic obstructive pulmonary disease. IL-36 comprises 4 isoforms: the proinflammatory IL-36α, IL-36β, and IL-36γ and the anti-inflammatory IL-36R antagonist. An imbalance between proinflammatory and anti-inflammatory IL-36 isoforms can contribute to the inflammatory fate of cells and tissues. IL-36 cytokines signal through an IL-36R heterodimer mediating their function through canonical signaling cacade, including the NF-B pathway. Prominent for its role in psoriasis, IL-36 has recently been associated with disease mechanisms in atopic dermatitis, hidradenitis suppurativa, neutrophilic dermatoses, autoimmune blistering disease, and Netherton syndrome. The major cutaneous source of IL-36 cytokines is keratinocytes, pointing to its role in the communication between the epidermis, innate (neutrophils, dendritic cells) immune system, and adaptive (T helper [Th]1 cells, Th17) immune system. Thus, cutaneous IL-36 signaling is crucial for the immunopathological outcome of various skin diseases. Consequently, the IL-36/IL-36R axis has recently been recognized as a promising drug target for the treatment of inflammatory disorders beyond psoriasis. This review summarizes the current update on IL-36 cytokines in inflammatory skin diseases.

IL-17A-driven psoriasis is critically dependent on IL-36 signaling

Plaque psoriasis is an autoinflammatory and autoimmune skin disease, affecting 1-3% of the population worldwide. Previously, high levels of IL-36 family cytokines were found in psoriatic skin lesions, thereby contributing to keratinocyte hyperproliferation and infiltration of immune cells such as neutrophils. While treatment with anti-IL36 receptor (IL36R) antibodies was recently approved for generalized pustular psoriasis (GPP), it remains unclear, if targeting the IL36R might also inhibit plaque psoriasis. Here we show that antibody-mediated inhibition of IL36R is sufficient to suppress imiquimod-induced psoriasis-like skin inflammation and represses the disease's development in a model that depends on IL-17A overexpression in the skin. Importantly, treatment with anti-IL36R antibodies inhibited skin inflammation and attenuated psoriasis-associated, systemic inflammation. This is possibly due to a widespread effect of IL36R inhibition, which not only suppresses pro-inflammatory gene expression in keratinocytes, but also the activation of other immune cells such as T-cells or dendritic cells. In conclusion, we propose that inhibition of the IL-36 signaling pathway might constitute an attractive, alternative approach for treating IL-17A-driven psoriasis and psoriasis-linked comorbidities.

Tertiary lymphoid structures and B lymphocytes: a promising therapeutic strategy to fight cancer

Tertiary lymphoid structures (TLSs) are clusters of lymphoid cells with an organization that resembles that of secondary lymphoid organs. Both structures share common developmental characteristics, although TLSs usually appear in chronically inflamed non-lymphoid tissues, such as tumors. TLSs contain diverse types of immune cells, with varying degrees of spatial organization that represent different stages of maturation. These structures support both humoral and cellular immune responses, thus the correlation between the existence of TLS and clinical outcomes in cancer patients has been extensively studied. The finding that TLSs are associated with better prognosis in some types of cancer has led to the design of therapeutic strategies based on promoting the formation of these structures. Agents such as chemokines, cytokines, antibodies and cancer vaccines have been used in combination with traditional antitumor treatments to enhance TLS generation, with good results. The induction of TLS formation therefore represents a novel and promising avenue for the treatment of a number of tumor types.

Tertiary lymphoid structures in pancreatic cancer: a new target for immunotherapy

Pancreatic cancer (PC) is extremely malignant and shows limited response to available immunotherapies due to the hypoxic and immunosuppressive nature of its tumor microenvironment (TME). The aggregation of immune cells (B cells, T cells, dendritic cells, etc.), which is induced in various chronic inflammatory settings such as infection, inflammation, and tumors, is known as the tertiary lymphoid structure (TLS). Several studies have shown that TLSs can be found in both intra- and peritumor tissues of PC. The role of TLSs in peritumor tissues in tumors remains unclear, though intratumoral TLSs are known to play an active role in a variety of tumors, including PC. The formation of intratumoral TLSs in PC is associated with a good prognosis. In addition, TLSs can be used as an indicator to assess the effectiveness of treatment. Targeted induction of TLS formation may become a new avenue of immunotherapy for PC. This review summarizes the formation, characteristics, relevant clinical outcomes, and clinical applications of TLSs in the pancreatic TME. We aim to provide new ideas for future immunotherapy of PC.

Potential skin health promoting benefits of costunolide: a therapeutic strategy to improve skin inflammation in imiquimod-induced psoriasis

Psoriasis is a recurrent inflammatory skin disease. IL-36-related cytokines are overexpressed in psoriasis, but the mechanism is not yet clear. Costunolide (Cos) is a sesquiterpenoid compound derived from the root of the traditional Chinese medicine Aucklandia lappa Decne. This study aimed to explore the mechanism of Cos on improving psoriasis-like skin inflammation. An in vivo model was established by applying imiquimod treatment to the back skin of mice, and an in vitro model was established by using polyinosinic-polycytidylic acid (Poly(I:C)) stimulated-mouse primary dermal fibroblasts to induce inflammation. The results showed that Cos improved the pathological changes of psoriasis-like skin inflammation. In addition, Cos could inhibit epidermal damage and inflammation-related expression and improve the occurrence of skin-related inflammation in both in vivo and in vitro experiments. The improvement of psoriasis-like skin inflammatory response might be through the P2X7R/IL-36 signaling pathway. Collectively, Cos has an inhibitory effect on the expression of psoriasis-like skin inflammation. This showed that Cos has potential skin health promoting benefits by preventing psoriasis-like skin inflammation.

Turning Tertiary Lymphoid Structures (TLS) into Hot Spots: Values of TLS in Gastrointestinal Tumors

Tertiary lymphoid structures (TLSs) are ectopic lymphocyte aggregation structures found in the tumor microenvironment (TME). Emerging evidence shows that TLSs are significantly correlated with the progression of gastrointestinal tumors, patients' prognosis, and the efficacy of adjuvant therapy. Besides, there are still some immunosuppressive factors in the TLSs that may affect the anti-tumor responses of TLSs, including negative regulators of anti-tumor immune responses, the immune checkpoint molecules, and inappropriate tumor metabolism. Therefore, a more comprehensive understanding of TLSs' responses in gastrointestinal tumors is essential to fully understand how TLSs can fully exert their anti-tumor responses. In addition, targeting TLSs with immune checkpoint inhibitors and vaccines to establish mature TLSs is currently being developed to reprogram the TME, further benefiting cancer immunotherapies. This review summarizes recent findings on the formation of TLSs, the mechanisms of their anti-tumor immune responses, and the association between therapeutic strategies and TLSs, providing a novel perspective on tumor-associated TLSs in gastrointestinal tumors.

Exploring the Molecular Pathogenesis, Pathogen Association, and Therapeutic Strategies against HPV Infection

The human papillomavirus (HPV), commonly documented as the cause of warts, has gained much interest recently due to its possible links to several types of cancer. HPV infection is discussed in this review from multiple angles, including its virology, epidemiology, etiology, immunology, clinical symptoms, and treatment. Recent breakthroughs in molecular biology have led to the development of new methods for detecting and treating HPV in tissue. There is no cure for HPV, and although vaccines are available to prevent infection with the most common HPV viruses, their utilization is limited. Destruction and excision are the primary treatment modalities. This review sheds light on the epidemiology, molecular pathogenesis, the association of several other pathogens with HPV, the latest treatment strategies available to treat the same, and an overview of the progress made and the obstacles still to be overcome in the fight against HPV infection.

The IL-1 Family and Its Role in Atherosclerosis

The IL-1 superfamily of cytokines is a central regulator of immunity and inflammation. The family is composed of 11 cytokines (with agonist, antagonist, and anti-inflammatory properties) and 10 receptors, all tightly regulated through decoy receptor, receptor antagonists, and signaling inhibitors. Inflammation not only is an important physiological response against infection and injury but also plays a central role in atherosclerosis development. Several clinical association studies along with experimental studies have implicated the IL-1 superfamily of cytokines and its receptors in the pathogenesis of cardiovascular disease. Here, we summarize the key features of the IL-1 family, its role in immunity and disease, and how it helps shape the development of atherosclerosis.

Plasma Levels of Interleukins 36α, 36β, and 37 in Patients with Psoriasis and Their Correlation with Disease Activity Parameters

Psoriasis is a chronic, proliferative, inflammatory skin disease characterised by skin lesions and systemic symptoms. Numerous cytokines are produced in psoriasis as a result of inflammation. The aim of this study was to examine the plasma concentrations of IL-36α, IL-36β, and IL-37 in psoriasis and their correlations with disease activity parameters. This study recruited 84 individuals, 53 with plaque-type psoriasis and 31 healthy controls. The plaque type of psoriasis is the most common type and is typically characterized by circular-to-oval red plaques distributed over body surfaces of the extremities and scalp. In patients with psoriasis, we observed statistically significantly decreased plasma concentrations of IL-36β and IL-37. The concentrations of IL-36α were increased in comparison with control group. The plasma concentrations of IL-36α and IL-36β were statistically significantly correlated with all tested parameters of disease activity: the Psoriasis Activity Severity Index, Dermatology Life Quality Index, and Body Surface Area Index. There were no statistically significant correlations between plasma levels of IL-37 and the tested parameters of disease activity. These results indicate a role of IL36α, IL-36β, and IL-37 in the pathogenesis of psoriasis.

Molecular and cellular regulation of psoriatic inflammation

This review highlights the molecular and cellular mechanisms underlying psoriatic inflammation with an emphasis on recent developments which may impact on treatment approaches for this chronic disease. We consider both the skin and the musculoskeletal compartment and how different manifestations of psoriatic inflammation are linked. This review brings a focus to the importance of inflammatory feedback loops that exist in the initiation and chronic stages of the condition, and how close interaction between the epidermis and both innate and adaptive immune compartments drives psoriatic inflammation. Furthermore, we highlight work done on biomarkers to predict the outcome of therapy as well as the transition from psoriasis to psoriatic arthritis.

The mechanism on Prevotella melaninogenica promoting the inflammatory progression of oral lichen planus

Oral lichen planus (OLP) is a common chronic inflammatory disease occurring in the oral mucosa. Bacteria is a key driver of mucosal immune response and can induce changes in gene expression and function of epithelial keratinocytes. IL-36γ can induce the expression of antimicrobial peptides, cytokines and chemokines, and is widely involved in many chronic inflammatory diseases. Our aim is to explore the role of IL-36γ in pathological process of OLP when Prevotella melaninogenica (P. melaninogenica) invades oral mucosa. The expression of IL-36γ in OLP lesions and mice was detected by immunohistochemistry. Recombinant human IL-36Gamma (rhIL-36γ) was used to treat oral keratinocytes and the expression levels of inflammatory cytokines were detected by qRT-PCR and ELISA. The expression of IL-36γ and TRPV1 was detected by western blotting following co-culturing P. melaninogenica with oral keratinocytes. The mRNA expression of IL-36γ was detected by qRT-PCR. From our results, IL-36γ was upregulated in OLP lesions. Exogenous rhIL-36γ promoted the expression of pro-inflammatory cytokines and antibacterial peptides in oral keratinocytes. The expression of IL-36γ was significantly increased following the stimulation of P. melaninogenica in oral keratinocytes and mice. TRPV1 activation was induced by P. melaninogenica and its activation enhanced the expression of IL-36γ. IL-36Ra could reduce the inflammation in OLP in vitro. In summary, overexpression of IL-36γ in OLP lesions could promote its pathogenesis by inducing inflammation. P. melaninogenica invasion of oral keratinocytes could induce the expression of IL-36γ by the activation of TRPV1, thereby regulating the interaction between bacteria and oral epithelial cells.

Modulation of IL-36-based inflammatory feedback loop through hepatocytes-derived IL-36R-P2X7R axis improves steatosis in alcoholic steatohepatitis

BACKGROUND AND PURPOSE

IL-36 is induced by proinflammatory cytokines and itself promotes inflammatory responses, shaping an IL-36-based inflammation loop. Although, hepatocytes, as "epithelial cell-like" hepatic parenchymal cells, produce IL-36 responses to drug-induced liver injury, little is known about the mechanistic role of the IL-36 signalling during the progression of alcoholic steatohepatitis (ASH). Regarding IL-36/IL-36R and P2X7R coregulates the inflammatory response, we elucidated the modulation of IL-36R-P2X7R-TLRs axis affected hepatocytes steatosis and IL-36-based inflammatory feedback loop that accompanies the onset of ASH.

EXPERIMENTAL APPROACH

C57BL/6J mice were subjected to chronic-plus-binge ethanol feeding or acute gavage with multiple doses of ethanol to establish ASH, followed by pharmacological inhibition or genetic silencing of IL-36R and P2X7R. AML12 cells or mouse primary hepatocytes were stimulated with alcohol, LPS plus ATP or Poly(I:C) plus ATP, followed by silencing of IL-36γ, IL-36R or P2X7R.

KEY RESULTS

P2X7R and IL-36R deficiency blocked the inflammatory loop, especially made by IL-36 cytokines, in hepatocytes of mice suffering from ASH. Pharmacological inhibition to P2X7R or IL-36R alleviated lipid accumulation and inflammatory response in ASH. IL-36R was indispensable for P2X7R modulated NLRP3 inflammasome activation in ASH and IL-36 led to a vicious cycle of P2X7R-driven inflammation in alcohol-exposed hepatocytes. TLR ligands promoted IL-36γ production in hepatocytes based on the synergism of P2X7R.

CONCLUSIONS AND IMPLICATIONS

Blockade of IL-36-based inflammatory feedback loop via IL-36R-P2X7R-TLRs-modulated NLRP3 inflammasome activation circumvented the steatosis and inflammation that accompanies the onset of ASH, suggesting that targeting IL-36 might serve as a novel therapeutic approach to combat ASH.

Interleukin-1 Receptor-Like 2: One Receptor, Three Agonists, and Many Implications

The interleukin (IL)-1 superfamily of cytokines comprises 11 pro- and anti-inflammatory cytokines, which play essential roles during the immune response. Several pathogenic pathways are initiated by IL-1RL2 (interleukin 1 receptor-like 2) signaling, also known as IL-36R, in the skin, lungs, and gut. IL-36 cytokines promote the secretion of proinflammatory cytokines and chemokines, upregulation of antimicrobial peptides, proliferation mediators, and adhesion molecules on endothelial cells. In addition, the IL-36-IL-1RL2 axis has an essential role against viral infections, including a potential role in COVID-19 pathology. The evidence presented in this review highlights the importance of the axis IL-36-IL-1RL2 in the development of several inflammation-related diseases and the healing process. It suggests that IL-1RL2 ligands have specific roles depending on the tissue or cell source. However, there is still much to discover about this cytokine family, their functions in other organs, and how they accomplish a dual effect in inflammation and healing.

Targeting IL-36 improves age-related coronary microcirculatory dysfunction and attenuates myocardial ischaemia-reperfusion injury in mice

Following myocardial infarction (MI), elderly patients have a poorer prognosis than younger patients, which may be linked to increased coronary microvessel susceptibility to injury. Interleukin-36 (IL-36), a newly discovered proinflammatory member of the IL-1 superfamily, may mediate this injury, but its role in the injured heart is currently not known. We first demonstrated the presence of IL-36(α/β) and its receptor (IL-36R) in ischemia/reperfusion-injured (IR-injured) mouse hearts and, interestingly, noted that expression of both increased with aging. An intravital model for imaging the adult and aged IR-injured beating heart in real time in vivo was used to demonstrate heightened basal and injury-induced neutrophil recruitment, and poorer blood flow, in the aged coronary microcirculation when compared with adult hearts. An IL-36R antagonist (IL-36Ra) decreased neutrophil recruitment, improved blood flow, and reduced infarct size in both adult and aged mice. This may be mechanistically explained by attenuated endothelial oxidative damage and VCAM-1 expression in IL-36Ra–treated mice. Our findings of an enhanced age-related coronary microcirculatory dysfunction in reperfused hearts may explain the poorer outcomes in elderly patients following MI. Since targeting the IL-36/IL-36R pathway was vasculoprotective in aged hearts, it may potentially be a therapy for treating MI in the elderly population.

Interleukin role in the regulation of endothelial cell pathological activation

Interleukins (ILs) are the group of cytokines firstly identified as expressed by leukocytes and playing different immunomodulatory functions. With increasing evidence of a constant crosstalk between leukocytes and endothelial cells in the regulation of immune cell differentiation and activation, a role of ILs also in endothelial cell stimulation and vascular inflammation has been shown. ILs act on endothelial cells both in an autocrine and a paracrine manner. In fact, a cross regulation is present among ILs expressed by different cell types, leading to amplification or blocking of the initial inflammatory signal with the secretion of additional ILs or involvement of other adjacent cells and tissues. Based on selective structural features, ILs can be divided into four major groups, a fifth group comprises ILs that do not fit into any of the other four. Most of the ILs playing a role in endothelial cell activation belong to the IL1-like cytokine group, but the number of ILs involved in vascular inflammation is constantly growing, and a special contribution of IL6, IL8, and IL17 has been underlined. This review aims at presenting current knowledge and at underling missing information about the role of IL in activating endothelial cells in selected pathological settings such as tumours, psoriasis, systemic sclerosis, and viral infection.

IL-36α and Lipopolysaccharide Cooperatively Induce Autophagy by Triggering Pro-Autophagic Biased Signaling

Autophagy is an intracellular catabolic process that controls infections both directly and indirectly via its multifaceted effects on the innate and adaptive immune responses. It has been reported that LPS stimulates this cellular process, whereas the effect of IL-36α on autophagy remains largely unknown. We therefore investigated how IL-36α modulates the endogenous and LPS-induced autophagy in THP-1 cells. The levels of LC3B-II and autophagic flux were determined by Western blotting. The intracellular localization of LC3B was measured by immunofluorescence assay. The activation levels of signaling pathways implicated in autophagy regulation were evaluated by using a phosphokinase array. Our results showed that combined IL-36α and LPS treatment cooperatively increased the levels of LC3B-II and Beclin-1, stimulated the autophagic flux, facilitated intracellular redistribution of LC3B, and increased the average number of autophagosomes per cell. The IL36α/LPS combined treatment increased phosphorylation of STAT5a/b, had minimal effect on the Akt/PRAS40/mTOR pathway, and reduced the levels of phospho-Yes, phospho-FAK, and phospho-WNK1. Thus, this cytokine/PAMP combination triggers pro-autophagic biased signaling by several mechanisms and thus cooperatively stimulates the autophagic cascade. An increased autophagic activity of innate immune cells simultaneously exposed to IL-36α and LPS may play an important role in the pathogenesis of Gram-negative bacterial infections.

Roles of IL-1 and IL-10 family cytokines in the progression of systemic lupus erythematosus: Friends or foes?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that can affect nearly every organ system in the body. Besides genetic and environmental factors, unbalanced pro-inflammatory and anti-inflammatory cytokines contribute to immune dysregulation, trigger an inflammatory response, and induce tissue and organ damage. Inflammatory responses in SLE can be promoted and/or maintained by the availability of cytokines that are overproduced systemically and/or in local tissues. Several key cytokines have been considered potential targets for the reduction of chronic inflammation in SLE. Recent studies indicated that dysregulated production of several cytokines, including those of the IL-1 family and IL-10 family, orchestrate immune activation and self-tolerance, play critical roles in the pathogenesis of SLE. Among IL-1 family cytokines, IL-1, IL-18, IL-33, IL-36, IL-37, and IL-38 had been the most thoroughly investigated in SLE. Additionally, IL-10 family cytokines, IL-10, IL-20, IL-22, IL-26, IL-28, and IL-29 are dysregulated in SLE. Therefore, a better understanding of the initiation and progression of SLE may provide suitable novel targets for therapeutic intervention. In this review, we discuss the involvement of inflammation in the pathogenesis of SLE, with a focus on IL-1 family and IL-10 family cytokines, and highlight pathophysiological approaches and therapeutic potential for treating SLE.

The Role of IL-37 and IL-38 in Obstetrics Abnormalities

There are two fairly common complications during pregnancy, i.e., gestational diabetes mellitus (GDM) and pre-eclampsia, which are independent, but are also closely linked in prevalence in pregnant women, with potential serious adverse consequences. IL-37 and IL-38, which belong to the IL-1 superfamily, participate in anti-inflammatory responses. Dysregulation of IL-37 and IL-38 has been observed in many auto-immune diseases. IL-37 is substantially reduced in the umbilical cords and placentas of GDM subjects, but IL-37 is significantly induced in the placentas of pre-eclampsia patients, suggesting there are differential regulatory roles of IL-37 in obstetrics, despite IL-37 being an anti-inflammatory mediator. Furthermore, IL-38 is substantially increased in the umbilical cords and placentas of GDM subjects, but minimal difference is observed in the placentas from pre-eclampsia patients. These data imply that IL-38 is also regulated independently within the diseased placentas. This review provides some insight for both basic scientists and medical practitioners to manage these patients effectively.

IL-36 in chronic inflammation and fibrosis - bridging the gap?

IL-36 is a member of the IL-1 superfamily and consists of three agonists and one receptor antagonist (IL-36Ra). The three endogenous agonists, IL-36α, -β, and -γ, act primarily as proinflammatory cytokines, and their signaling through the IL-36 receptor (IL-36R) promotes immune cell infiltration and secretion of inflammatory and chemotactic molecules. However, IL-36 signaling also fosters secretion of profibrotic soluble mediators, suggesting a role in fibrotic disorders. IL-36 isoforms and IL-36 have been implicated in inflammatory diseases including psoriasis, arthritis, inflammatory bowel diseases, and allergic rhinitis. Moreover, IL-36 has been connected to fibrotic disorders affecting the kidney, lung, and intestines. This review summarizes the expression, cellular source, and function of IL-36 in inflammation and fibrosis in various organs, and proposes that IL-36 modulation may prove valuable in preventing or treating inflammatory and fibrotic diseases and may reveal a mechanistic link between inflammation and fibrosis.

Propionate and Butyrate Produced by Gut Microbiota after Probiotic Supplementation Attenuate Lung Metastasis of Melanoma Cells in Mice

SCOPE

The beneficial effects of probiotics in reducing gastrointestinal inflammation and in preventing colorectal cancer have been reported, but the mechanism underlying the immunomodulatory effect of probiotics in inhibiting extra-intestinal tumor progression remains unclear.

METHODS AND RESULTS

This study shows that probiotic supplementation attenuate lung metastasis of melanoma cells in mice. Feeding mice with VSL#3 probiotics change the composition and proportion of gut microbiota. The changes in gut bacteria composition, such as in the abundance of Lachnospiraceae, Streptococcus, and Lachnoclostridium, are associated with the production of short-chain fatty acids in the gut. The concentrations of propionate and butyrate are upregulated in gut and blood after feeding VSL#3, and the increase in propionate and butyrate levels promotes the expression of chemokine (C-C motif) ligand 20 (CCL20) in lung endothelial cells and the recruitment of T helper 17 (Th17) cells to the lungs via the CCL20/chemokine receptor 6 axis. The recruitment of Th17 cells decreases the number of tumor foci in lungs and attenuates the lung metastasis of melanoma cells in mice.

CONCLUSIONS

The results provide new information on the role and mechanisms of action of probiotics in attenuating extra-intestinal tumor metastasis.

Tertiary Lymphoid Structures in Cancer: The Double-Edged Sword Role in Antitumor Immunity and Potential Therapeutic Induction Strategies

The complex tumor microenvironment (TME) plays a vital role in cancer development and dramatically determines the efficacy of immunotherapy. Tertiary lymphoid structures (TLSs) within the TME are well recognized and consist of T cell-rich areas containing dendritic cells (DCs) and B cell-rich areas containing germinal centers (GCs). Accumulating research has indicated that there is a close association between tumor-associated TLSs and favorable clinical outcomes in most types of cancers, though a minority of studies have reported an association between TLSs and a poor prognosis. Overall, the double-edged sword role of TLSs in the TME and potential mechanisms need to be further investigated, which will provide novel therapeutic perspectives for antitumor immunoregulation. In this review, we focus on discussing the main functions of TLSs in the TME and recent advances in the therapeutic manipulation of TLSs through multiple strategies to enhance local antitumor immunity.

Increased angiogenesis and migration of dermal microvascular endothelial cells from patients with psoriasis

Psoriasis displays both increased angiogenesis and microvascular dilation in the skin, while human dermal microvascular endothelial cells (HDMECs) are involved in angiogenesis and microvascular dilation. Whether the functions of HDMECs are altered in psoriatic skin versus healthy skin remain unknown. Here, we isolated HDMECs from the skin of 10 patients with psoriasis and 10 healthy subjects and compared angiogenesis, proliferation, migration and cell metabolism between psoriatic HDMECs and normal HDMECs. We found that the morphology of primary HDMECs was comparable between psoriatic HDMECs and normal HDMECs. After passage, psoriatic HDMECs displayed larger cell size and wider intercellular space. In addition to DiI-Ac-LDL (DiI-labelled acetylated low-density lipoprotein) uptake, expression levels of CD31, vWF (von Willebrand factor) and LYVE-1 were comparable in psoriatic HDMECs versus normal HDMECs. However, psoriatic HDMECs exhibited increased tube formation (numbers of nodes and meshes, p < 0.05) and migration (numbers of migrated cells, p < 0.001) and reductions in proliferation (growth rates, p < 0.05) and energy metabolism (oxygen consumption rate and extracellular acidification rate, p < 0.05) compared with normal HDMECs. Therefore, psoriatic HDMECs display an increased angiogenesis and migration and decreased proliferation and metabolic activity, suggesting a pathogenic role of HDMECs in psoriasis.

Association of serum CCL20 levels with pulmonary vascular involvement and primary biliary cholangitis in patients with systemic sclerosis

AIM

Systemic sclerosis (SSc) is a chronic autoimmune disease resulting in vasculopathy and fibrosis of the skin and major internal organs. Especially, interstitial lung disease and pulmonary arterial hypertension are the leading causes of mortality. C-C motif ligand 20 (CCL20) is known as a homeostatic and inflammatory chemokine, which is associated with fibrosis and angiogenesis and constantly expressed in organs involved in SSc. Therefore, we investigated the potential contribution of CCL20 to the development of SSc.

METHOD

We conducted cross-sectional analyses of 67 SSc patients and 20 healthy controls recruited in a single center for 9 years. Serum CCL20 levels were measured by enzyme-linked immunosorbent assay. Statistical analyses were performed with the Mann-Whitney U test, the Kruskal-Wallis test followed by Dunn's multiple comparison test, Fisher's exact probability test and the Spearman's rank correlation coefficient.

RESULTS

SSc patients had significantly higher serum CCL20 levels than healthy controls. In SSc patients, serum CCL20 levels correlated inversely with the percentage of predicated diffusion lung capacity for carbon monoxide and positively with mean pulmonary artery pressure (mPAP). In addition, SSc patients with increased serum CCL20 levels had anti-mitochondrial antibody M2 titer significantly elevated relative to those with normal levels, and SSc patients with asymptomatic primary biliary cholangitis (PBC) possessed higher serum CCL20 levels than those without. Importantly, serum CCL20 levels were associated positively with mPAP values and PBC presence by multivariate regression analysis.

CONCLUSION

Serum CCL20 levels may be involved in the development of pulmonary vascular involvement leading to pulmonary arterial hypertension and asymptomatic PBC in SSc patients.

IL-36 cytokines and gut immunity

Interleukin 36 (IL-36) constitutes a group of cytokines that belong to the IL-1 superfamily. Emerging evidence has suggested a role of IL-36 in the pathogenesis of many inflammatory disorders. Intriguingly, in the gastrointestinal tract, IL-36 has a rather complex function. IL-36 receptor ligands are overexpressed in both animal colitis models and human IBD patients and may play both pathogenic and protective roles, depending on the context. IL-36 cytokines comprise three receptor agonists: IL-36α, IL-36β and IL-36γ, and two receptor antagonists: IL-36Ra and IL-38. All IL-36 receptor agonists bind to the IL-36R complex and exert pleiotropic effects during inflammatory settings. Here, we first briefly review the processing and secretion of IL-36 cytokines. We then focus on the current understanding of the immunology effects of IL-36 in gut immunity. In addition, we also discuss the ongoing trials that aim to blockage IL-36R signalling for treating chronic intestinal inflammation and present some unexplored questions regarding IL-36 research.

Interleukin-36 Cytokine/Receptor Signaling: A New Target for Tissue Fibrosis

Tissue fibrosis is a major unresolved medical problem, which impairs the function of various systems. The molecular mechanisms involved are poorly understood, which hinders the development of effective therapeutic strategies. Emerging evidence from recent studies indicates that interleukin 36 (IL-36) and the corresponding receptor (IL-36R), a newly-characterized cytokine/receptor signaling complex involved in immune-inflammation, play an important role in the pathogenesis of fibrosis in multiple tissues. This review focuses on recent experimental findings, which implicate IL-36R and its associated cytokines in different forms of organ fibrosis. Specifically, it outlines the molecular basis and biological function of IL-36R in normal cells and sums up the pathological role in the development of fibrosis in the lung, kidney, heart, intestine, and pancreas. We also summarize the new progress in the IL-36/IL-36R-related mechanisms involved in tissue fibrosis and enclose the potential of IL-36R inhibition as a therapeutic strategy to combat pro-fibrotic pathologies. Given its high association with disease, gaining new insight into the immuno-mechanisms that contribute to tissue fibrosis could have a significant impact on human health.

IL36 indicating good prognosis in human Hepatocellular Carcinoma

Background and Aim: Hepatocellular carcinoma (HCC) is the leading cause of cancer death in men before the age of 60 years in China. Interleukin (IL)36 played important roles in antitumor immune responses, but its role in HCC is still unknown. We aimed to explore the correlation between IL36 and prognosis of HCC patients.

Methods: The expression of IL36 was measured by Immunohistochemistry (IHC), serum Enzyme-linked Immunosorbent Assay (ELISA) and flow cytometry (FCM). Chi-square test was performed to analyze the relationship between IL36 expression and clinical parameters of HCC patients. The correlation between IL36 expression and prognosis of HCC patients was evaluated by Kaplan-Meier method and Cox regression analysis.

Results: The IL36 expression in HCC tumor samples was lower than that in paired peri-tumor samples; the analyses suggested that there was no correlation between IL36 expression and age, gender, and tumor size, but tight relationship between IL36 expression and liver cirrhosis, metastasis and some other clinical parameters. The results of Kaplan-Meier analysis indicated positive expression of IL36 could induce high survival rate of patients. The detection of IL36 with ELISA suggested that expression of IL36 in serum was the highest in patients of HCC, other than the chronic hepatitis patients and the healthy. The result of FCM suggested the expression of IL36 was higher in CD4+ T cells than other immune cells.

Conclusions: There is a close relationship between the expression of IL36 and the prognosis of HCC, higher expression of IL36 suggested better prognosis and longer survival of HCC.

Six reference-quality genomes reveal evolution of bat adaptations

Bats possess extraordinary adaptations, including flight, echolocation, extreme longevity and unique immunity. High-quality genomes are crucial for understanding the molecular basis and evolution of these traits. Here we incorporated long-read sequencing and state-of-the-art scaffolding protocols1 to generate, to our knowledge, the first reference-quality genomes of six bat species (Rhinolophus ferrumequinum, Rousettus aegyptiacus, Phyllostomus discolor, Myotis myotis, Pipistrellus kuhlii and Molossus molossus). We integrated gene projections from our 'Tool to infer Orthologs from Genome Alignments' (TOGA) software with de novo and homology gene predictions as well as short- and long-read transcriptomics to generate highly complete gene annotations. To resolve the phylogenetic position of bats within Laurasiatheria, we applied several phylogenetic methods to comprehensive sets of orthologous protein-coding and noncoding regions of the genome, and identified a basal origin for bats within Scrotifera. Our genome-wide screens revealed positive selection on hearing-related genes in the ancestral branch of bats, which is indicative of laryngeal echolocation being an ancestral trait in this clade. We found selection and loss of immunity-related genes (including pro-inflammatory NF-κB regulators) and expansions of anti-viral APOBEC3 genes, which highlights molecular mechanisms that may contribute to the exceptional immunity of bats. Genomic integrations of diverse viruses provide a genomic record of historical tolerance to viral infection in bats. Finally, we found and experimentally validated bat-specific variation in microRNAs, which may regulate bat-specific gene-expression programs. Our reference-quality bat genomes provide the resources required to uncover and validate the genomic basis of adaptations of bats, and stimulate new avenues of research that are directly relevant to human health and disease1.

IL-36 signaling in keratinocytes controls early IL-23 production in psoriasis-like dermatitis

IL-36R signaling plays an important role in the pathogenesis of psoriasis. We ought to assess the specific function of IL-36R in keratinocytes for the pathology of Aldara-induced psoriasis-like dermatitis. Il36r ΔK mice presenting deletion of IL-36R in keratinocytes were similarly resistant to Aldara-induced ear inflammation as Il36r -/- mice, but acanthosis was only prevented in Il36r -/- mice. FACS analysis revealed that IL-36R signaling in keratinocytes is mandatory for early neutrophil infiltration in Aldara-treated ears. RNASeq and qRT-PCR experiments demonstrated the crucial role of IL-36R signaling in keratinocytes for induction of IL-23, IL-17, and IL-22 at early time points. Taken together, our results demonstrate that IL-36R signaling in keratinocytes plays a major role in the induction of Aldara-induced psoriasis-like dermatitis by triggering early production of IL-23/IL-17/IL-22 cytokines and neutrophil infiltration.

Interleukin (IL)-17/IL-36 axis participates to the crosstalk between endothelial cells and keratinocytes during inflammatory skin responses

In inflammatory skin conditions, such as psoriasis, vascular enlargement is associated with endothelial cell proliferation, release of cytokines and adhesion molecule expression. Interleukin (IL)-17A is a pro-inflammatory cytokine mainly secreted by T helper-17 cells that is critically involved in psoriasis pathogenesis. IL-36α, IL-36β and IL-36γ are also inflammatory cytokines up-regulated in psoriasis and induced by various stimuli, including IL-17A. In this study, we found that human keratinocytes are the main source of IL-36, in particular of IL-36γ. This cytokine was strongly induced by IL-17A and, together with IL-17A, efficiently activated human dermal microvascular endothelial cells (HDMECs), which expressed both IL-17 and IL-36 receptors. Both IL-36γ and IL-17A induced cell proliferation through specific molecular cascades involving ERK1/2 only or ERK1/2, STAT3 and NF-κB, respectively. We highlighted the intense IL-17A- and IL-36γ -dependent interplay between keratinocytes and HDMECs, likely active in the psoriatic lesions and leading to the establishment of a cytokine network responsible for the development and maintenance of the inflamed state. IL-17A or IL-36γ showed in HDMECs a synergic activity with TNF-α by potently inducing inflammatory cytokine/chemokine release and ICAM-1 expression. We also investigated the involvement of IL-36γ and VEGF-A, substantially reduced in lesional skin of psoriatic patients pharmacologically treated with the anti-IL-17A antibody Secukinumab. Importantly, keratinocyte-derived IL-36γ represented an additional pro-angiogenic mediator of IL-17A. We observed that keratinocyte-derived VEGF-A influenced proliferation but did not act on expression of adhesion molecules in HDMECs. On the other hand, inhibition of IL-36γ released by IL-17A-treated keratinocytes impaired either proliferation or ICAM-1 expression both in HDMECs and in an in vivo murine model of psoriasis. Taken together, our data demonstrated that IL-17A and IL-36γ are highly involved in endothelial cells/keratinocytes crosstalk in inflammatory skin conditions.

Deficiency of Interleukin-36 Receptor Protected Cardiomyocytes from Ischemia-Reperfusion Injury in Cardiopulmonary Bypass

Background

Interleukin-36 has been demonstrated to be involved in inflammatory responses. Inflammatory responses due to ischemia-reperfusion injury following cardiopulmonary bypass (CPB) can cause heart dysfunction or damage.

Material/Methods

The CPB models were constructed in IL-36R−/−, IL-36RN−/−, and wild-type SD rats. Ultrasonic cardiography and ELISA were used to evaluate the cardiac function and measuring myocardial biomarker levels in different groups. TUNEL assay was used to evaluate apoptosis. Western blot assays and RT-PCR were performed to measure the expression of chemokines and secondary inflammatory cytokines in the heart. Oxidative stress in tissue and cultured cells was assessed using a DCFH-DA fluorescence probe and quantification of superoxide dismutase activity.

Results

Improved systolic function and decreased serum levels of myocardial damage biomarkers were found in IL-36R−/− rats compared to WT rats, while worse cardiac function and cardiomyocyte IR injury were observed in IL-36RN−/− rats compared to WT rats. TUNEL staining and Western blot analyses found that cardiomyocyte apoptosis and inflammation were significantly lower in the hearts of IL-36R−/− rats compared with that of WT rats. Oxidative stress was significantly lower in IL-36R−/− rats compared to WT rats. iNOS expression was significantly reduced, while eNOS expression was increased in the hearts of IL-36R−/− rats. Silencing of IL-36R expression in vitro activated SIRT1/FOXO1/p53 signaling in cardiomyocytes.

Conclusions

IL-36R deficiency in cardiomyocytes repressed infiltration of bone marrow-derived inflammatory cells and oxidative stress dependent on SIRT1-FOXO1 signaling, thus protecting cardiomyocytes and improving cardiac function in CPB model rats.

4-methylumbelliferone inhibits clonogenic potency by suppressing high molecular weight-hyaluronan in fibrosarcoma cells

The inflammatory response is closely associated with cancer cell survival. It has been reported that inflammatory signaling cascades promote tumor survival and exert detrimental effects in normal tissue. Hyaluronans have different cellular functions depending on their molecular weights and high molecular weight-hyaluronan (HMW-HA) exhibits anti-inflammatory effects. A previous study determined that the co-administration of 4-methylumbelliferone (4-MU) and X-ray irradiation enhanced anti-tumor and anti-inflammatory effects in HT1080 human fibrosarcoma cells. However, many mechanisms underlie the effect of hyaluronan molecular weight on cells and the induction of anti-inflammatory effects via 4-MU. The present study aimed to determine the relationship between hyaluronan synthesis inhibition by 4-MU and its anti-inflammatory and radio-sensitizing effect in the context of hyaluronan molecular weight. The hyaluronan concentration following 2 Gy X-ray irradiation and/or 4-MU administration was analyzed via ELISA. Additionally, the mRNA expressions of hyaluronan synthase (HAS) by 4-MU and various inflammatory cytokines and interleukins (IL) following exogenous HMW-HA administration were evaluated via Reverse transcription-quantitative PCR. Invasive potential was assessed by matrigel transwell assays and cell survival following exposure to 4-MU with HMW-HA was determined using a clonogenic potency assay. The results of the present study demonstrated that 4-MU suppressed HMW-HA production by inhibiting HAS2 and HAS3 expression. In addition, the surviving fraction of fibrosarcoma cells were rescued from the cell-killing effect of 4-MU via the exogenous administration of HMW-HA. The mRNA levels of certain inflammatory cytokines, including IL-1α, IL-36γ and IL-37 were elevated following HMW-HA administration. The surviving fraction of cells irradiated with 2 Gy alone did not increase following exogenous HMW-HA administration. The results of the present study indicated that the radio-sensitizing effect of 4-MU and the inhibitory effect on hyaluronan synthesis were not closely associated. It was also revealed that IL-1α, IL-36γ and IL-37 were associated with the cell-killing effect of 4-MU in HT1080 cells.

Interleukin-23 pathway at the enthesis: The emerging story of enthesitis in spondyloarthropathy

The inflammatory disorders collectively termed the seronegative spondyloarthropathies (SpA) include ankylosing spondylitis (AS), psoriatic arthritis (PsA), reactive arthritis, the arthritis associated with inflammatory bowel disease including Crohn's disease and ulcerative colitis, the arthritis related to anterior uveitis, and finally, somewhat controversially Behcet's disease. All of these diseases are associated with SNPs in the IL-23R or the interleukin-23 (IL-23) cytokine itself and related downstream signaling JAK pathway genes and the interleukin-17 (IL-17) pathway. In rheumatoid arthritis, the target of the immune response is the synovium but the SpA disorders target the tendon, ligament, and joint capsule skeletal anchorage points that are termed entheses. The discovery that IL-23R-expressing cells were ensconced in healthy murine enthesis, and other extraskeletal anchorage points including the aortic root and the ciliary body of the eye and that systemic overexpression of IL-23 resulted in a severe experimental SpA, confirmed a fundamentally different immunobiology to rheumatoid arthritis. Recently, IL-23R-expressing myeloid cells and various innate and adaptive T cells that produce IL-17 family cytokines have also been described in the human enthesis. Blockade of IL-23 pathway with either anti-p40 or anti-p19 subunits has resulted in some spectacular therapeutic successes in psoriasis and PsA including improvement in enthesitis in the peripheral skeleton but has failed to demonstrate efficacy in AS that is largely a spinal polyenthesitis. Herein, we discuss the known biology of IL-23 at the human enthesis and highlight the remarkable emerging story of this unique skeletal tissue.

Pathogenic role of exosomes and microRNAs in HPV-mediated inflammation and cervical cancer: A review

Cervical cancer (CC) is the fourth most common cause of cancer death in women. The most important risk factor for the development of CC is cervical infection with human papilloma virus (HPV). Inflammation is a protective strategy that is triggered by the host against pathogens such as viral infections that acts rapidly to activate the innate immune response. Inflammation is beneficial if it is brief and well controlled; however, if the inflammation is excessive or it becomes of chronic duration, it can produce detrimental effects. HPV proteins are involved, both directly and indirectly, in the development of chronic inflammation, which is a causal factor in the development of CC. However, other factors may also have a potential role in stimulating chronic inflammation. MicroRNAs (miRNAs) (a class of noncoding RNAs) are strong regulators of gene expression. They have emerged as key players in several biological processes, including inflammatory pathways. Abnormal expression of miRNAs may be linked to the induction of inflammation that occurs in CC. Exosomes are a subset of extracellular vesicles shed by almost all types of cells, which can function as cargo transfer vehicles. Exosomes contain proteins and genetic material (including miRNAs) derived from their parent cells and can potentially affect recipient cells. Exosomes have recently been recognized to be involved in inflammatory processes and can also affect the immune response. In this review, we discuss the role of HPV proteins, miRNAs and exosomes in the inflammation associated with CC.

IL-36 Signaling in the Tumor Microenvironment

The ability of the immune system to prevent or control the growth of tumor cells is critically dependent on inflammatory processes that lead to the activation, expansion, and recruitment of antitumor effector cells into the tumor microenvironment (TME). These processes are orchestrated by soluble cytokines produced in tissues that alarm local immune surveillance cells (such as dendritic cells, DCs) to mobilize protective antitumor immune populations (B cells, T cells). The interleukin (IL)-36 family of pro-inflammatory cytokines plays an important role in multiple disease processes, ranging from an instigator of autoimmune psoriasis to an initiator of therapeutic immune responses against tumor cells. This chapter will focus on the biologic role of immunomodulatory IL-36 family cytokines in the cancer setting and their potential utility in the design of effective interventional therapies. (127 words).

Function and Regulation of IL-36 Signaling in Inflammatory Diseases and Cancer Development

The IL-36 subfamily of cytokines belongs to the IL-1 superfamily and consists of three pro-inflammatory agonists IL-36α, IL-36β, IL-36γ, and an IL-36 receptor (IL-36R) antagonist, IL-36Ra. These IL-36 cytokines function through a common receptor to modulate innate and adaptive immune responses. IL-36 cytokines are expressed as inactive precursors and require proteolytic processing to become fully active. Upon binding to IL-36R, IL-36 agonists augment the expression and production of inflammatory cytokines via activating signaling pathways. IL-36 is mainly expressed in epidermal, bronchial, and intestinal epithelial cells that form the barrier structures of the body and regulates the balance between pro-inflammatory and anti-inflammatory cytokine production at these tissue sites. Dysregulation of IL-36 signaling is a major etiological factor in the development of autoimmune and inflammatory diseases. Besides its critical role in inflammatory skin diseases such as psoriasis, emerging evidence suggests that aberrant IL-36 activities also promote inflammatory diseases in the lung, kidneys, and intestines, underscoring the potential of IL-36 as a therapeutic target for common inflammatory diseases. The role of IL-36 signaling in cancer development is also under investigation, with limited studies suggesting a potential anti-tumor effect. In this comprehensive review, we summarize current knowledge regarding the expression, activation, regulatory mechanisms, and biological functions of IL-36 signaling in immunity, inflammatory diseases, and cancer development.

Biology of IL-36 Signaling and Its Role in Systemic Inflammatory Diseases

Interleukin (IL)-36 is a member of the IL-1 superfamily and includes three agonists (IL-36α, IL-36β, and IL-36γ) and an antagonist (IL-36Ra). IL-36 agonists bind to heterodimeric receptor complexes. Then, the heterotrimer complexes signal via intracellular functional domains, binding to downstream signaling proteins and inducing inflammatory responses. In this review, we summarized the current knowledge about the biological role of IL-36 and its correlation with systemic inflammatory diseases. The information collected will help to increase the understanding of the potential of IL-36 and may give clues for developing novel therapeutic strategies.

Increased serum IL-36β and IL-36γ levels in patients with neuromyelitis optica spectrum disorders: association with disease activity

Background

Interleukin 36 (IL-36) cytokines belong to the IL-1 family and play an important role in some autoimmune diseases. However, the relationship between IL-36 and neuromyelitis optica spectrum disorders (NMOSD) remains unclear.

Methods

We determined serum IL-36α, IL-36β and IL-36γ levels and assessed correlations with clinical characteristics in 50 NMOSD patients and 30 healthy controls (HC).

Results

The concentrations of serum IL-36β and IL-36γ were significantly higher in patients with NMOSD than in HCs and decreased during remission. Serum IL-36β levels were positively correlated with the annual relapse rate (ARR), spinal cord lesion length and Expanded Disability Status Scale (EDSS) scores.

Conclusions

Serum IL-36β and IL-36γ levels were related to disease activity in NMOSD patients and may be important biomarkers of NMOSD.

The Significance of IL-36 Hyperactivation and IL-36R Targeting in Psoriasis

Psoriasis is an immune-mediated inflammatory skin disease that involves mainly T helper (Th)17, Th1 and Th22 lymphocytes, which cause hyper-proliferation of the epidermis with aberrant differentiation of keratinocytes, and local production of chemokines and cytokines. These fuel a self-amplifying loop where these products act on T cells to perpetuate cutaneous inflammatory processes. Among the various inflammatory mediators involved, interleukin (IL)-36 cytokines are important for the recruitment and activation of neutrophils and Th17 cells in psoriatic skin. In particular, IL-36s induce chemokines and cytokines interfere with differentiation/cornification programs in the epidermis, as well as promote pathological angiogenesis and endothelial cell activation. IL-36 cytokines belong to the IL-1 family, and comprise IL-36α, IL-36β, and IL-36γ agonists as well as IL-36 receptor antagonist and IL-38 antagonists. IL-36 cytokines are up-regulated in psoriatic epidermis, and their expression is strongly induced by TNF-α and IL-17. Contrarily, IL-38 antagonist is downregulated, and its impaired expression may be relevant to the dysregulated inflammatory processes induced by IL-36. Here, we discuss on the pathogenic mechanisms leading to the altered balance of IL-36 agonists/antagonists and the significance of this dysregulation in psoriasis. Collection of the information will provide a theoretical basis for the development of novel therapeutic strategies based on IL-36 agonist/antagonist manipulation in psoriasis.

IL-1 Family Cytokine Regulation of Vascular Permeability and Angiogenesis

The IL-1 family of cytokines are well-known for their primary role in initiating inflammatory responses both in response to and acting as danger signals. It has long been established that IL-1 is capable of simultaneously regulating inflammation and angiogenesis, indeed one of IL-1's earliest names was haemopoeitn-1 due to its pro-angiogenic effects. Other IL-1 family cytokines are also known to have roles in mediating angiogenesis, either directly or indirectly via induction of proangiogenic factors such as VEGF. Of note, some of these family members appear to have directly opposing effects in different tissues and pathologies. Here we will review what is known about how the various IL-1 family members regulate vascular permeability and angiogenic function in a range of different tissues, and describe some of the mechanisms employed to achieve these effects.