Mast Cell Cytokines IL-1, IL-33, and IL-36 Mediate Skin Inflammation in Psoriasis: A Novel Therapeutic Approach with the Anti-Inflammatory Cytokines IL-37, IL-38, and IL-1Ra

Single-cell technologies in psoriasis

Psoriasis is a chronic and recurrent inflammatory skin disorder. The primary manifestation of psoriasis arises from disturbances in the cutaneous immune microenvironment, but the specific functions of the cellular components within this microenvironment remain unknown. Recent advancements in single-cell technologies have enabled the detection of multi-omics at the level of individual cells, including single-cell transcriptome, proteome, and metabolome, which have been successfully applied in studying autoimmune diseases, and other pathologies. These techniques allow the identification of heterogeneous cell clusters and their varying contributions to disease development. Considering the immunological traits of psoriasis, an in-depth exploration of immune cells and their interactions with cutaneous parenchymal cells can markedly advance our comprehension of the mechanisms underlying the onset and recurrence of psoriasis. In this comprehensive review, we present an overview of recent applications of single-cell technologies in psoriasis, aiming to improve our understanding of the underlying mechanisms of this disorder.

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.

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

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

Emerging functions and therapeutic targets of IL-38 in central nervous system diseases

Interleukin (IL)-38 is a newly discovered cytokine of the IL-1 family, which binds various receptors (i.e., IL-36R, IL-1 receptor accessory protein-like 1, and IL-1R1) in the central nervous system (CNS). The hallmark physiological function of IL-38 is competitive binding to IL-36R, as does the IL-36R antagonist. Emerging research has shown that IL-38 is abnormally expressed in the serum and brain tissue of patients with ischemic stroke (IS) and autism spectrum disorder (ASD), suggesting that IL-38 may play an important role in neurological diseases. Important advances include that IL-38 alleviates neuromyelitis optica disorder (NMOD) by inhibiting Th17 expression, improves IS by protecting against atherosclerosis via regulating immune cells and inflammation, and reduces IL-1β and CXCL8 release through inhibiting human microglial activity post-ASD. In contrast, IL-38 mRNA is markedly increased and is mainly expressed in phagocytes in spinal cord injury (SCI). IL-38 ablation attenuated SCI by reducing immune cell infiltration. However, the effect and underlying mechanism of IL-38 in CNS diseases remain inadequately characterized. In this review, we summarize the biological characteristics, pathophysiological role, and potential mechanisms of IL-38 in CNS diseases (e.g., NMOD, Alzheimer's disease, ASD, IS, TBI, and SCI), aiming to explore the therapeutic potential of IL-38 in the prevention and treatment of CNS diseases.

Immune cells in the epithelial immune microenvironment of psoriasis: emerging therapeutic targets

Psoriasis is a chronic autoimmune inflammatory disease characterized by erroneous metabolism of keratinocytes. The development of psoriasis is closely related to abnormal activation and disorders of the immune system. Dysregulated skin protective mechanisms can activate inflammatory pathways within the epithelial immune microenvironment (EIME), leading to the development of autoimmune-related and inflammatory skin diseases. In this review, we initially emphasized the pathogenesis of psoriasis, paying particular attention to the interactions between the abnormal activation of immune cells and the production of cytokines in psoriasis. Subsequently, we delved into the significance of the interactions between EIME and immune cells in the emergence of psoriasis. A thorough understanding of these immune processes is crucial to the development of targeted therapies for psoriasis. Finally, we discussed the potential novel targeted therapies aimed at modulating the EIME in psoriasis. This comprehensive examination sheds light on the intricate underlying immune mechanisms and provides insights into potential therapeutic avenues of immune-mediated inflammatory diseases.

The elevation of plasma galectin-9 levels in patients with psoriasis and its associations with inflammatory and immune checkpoint molecules in skin tissues

Psoriasis is a chronic, immune-mediated disorder that mainly affects the skin, with an estimated global prevalence of 2-3%. Galectin-9 (Gal-9) is a β-galactoside-binding lectin capable of promoting or suppressing the progression of infectious and immune-mediated diseases. Here, we determined if the expression of Gal-9 is observed in psoriasis. Gal-9 levels were measured in plasma of psoriasis (n = 62) and healthy control (HC) (n = 31) using an enzyme-linked immunosorbent assay. In addition, skin samples from seven patients were screened for RNA transcriptomes and the expression of Gal-9 was compared with inflammatory, immune checkpoint molecules (ICMs) and Foxp3. The plasma Gal-9 levels in patients with psoriasis were significantly higher (841 pg/mL) than in HCs (617 pg/mL) (P < 0.0001) and were associated with white blood cell numbers, eosinophils (%) and alanine transaminase. The levels of inflammatory molecules IL-36B, IL-17RA, IL-6R, IL-10, IRF8, TGFb1, and IL-37, and those of ICMs of Tim-3, CTLA-4, CD86, CD80, PD-1LG2, CLEC4G, and Foxp3 were significantly correlated with Gal-9 (LGALS9) in skin. However, HMGB1, CD44, CEACAM1 and PDL1-known to be associated with a variety of Gal-9 biological functions were not correlated with LGALS9. Thus, it is likely that Gal-9 expression affects the disease state of PS.

Interleukin-36 is overexpressed in human sepsis and IL-36 receptor deletion aggravates lung injury and mortality through epithelial cells and fibroblasts in experimental murine sepsis

BACKGROUND

Sepsis is defined as a life-threatening syndrome caused by an unbalanced host response to infection. The role of interleukin (IL)-36 cytokines binding to the IL-36 receptor (IL-36R) in host response during sepsis remains unknown.

METHODS

Serum IL-36 level was measured in 47 septic patients sampled on the day of intensive care unit (ICU) and emergency department admission, 21 non-septic ICU patient controls, and 21 healthy volunteers. In addition, the effects of IL-36R deletion on host inflammatory response in cecal ligation and puncture (CLP)-induced polymicrobial sepsis was determined.

RESULTS

On the day of ICU and emergency department admission, the patients with sepsis showed a significant increase in serum IL-36 levels compared with ICU patient controls and healthy volunteers, and the serum IL-36 levels were related to the severity of sepsis. Non-survivors of septic patients displayed significantly lower serum IL-36 levels compared with survivors. A high serum IL-36 level in ICU and emergency department admission was associated with 28-day mortality, and IL-36 was found to be an independent predictor of 28-day mortality in septic patients by logistic regression analysis. Furthermore, IL-36R deletion increased lethality in CLP-induced polymicrobial sepsis. Septic mice with IL-36R deletion had higher bacterial load and demonstrated more severe multiple organ injury (including lung, liver, and kidney) as indicated by clinical chemistry and histopathology. Mechanistically, IL-36R ligands released upon lung damage activated IL-36R+lung fibroblasts thereby inducing expression of the antimicrobial protein lipocalin 2. Moreover, they induced the apoptosis of lung epithelial cells.

CONCLUSIONS

Septic patients had elevated serum IL-36 levels, which may correlate with disease severity and mortality. In experimental sepsis, we demonstrated a previously unrecognized role of IL-36R deletion in increasing lethality.

Potential Role of IL-37 in Atopic Dermatitis

Interleukin 37 (IL-37) is a recently discovered member of the IL-1 cytokine family that appears to have anti-inflammatory and immunosuppressive effects in various diseases. IL-37 acts as a dual-function cytokine, exerting its effect extracellularly by forming a complex with the receptors IL-18 α (IL-18Rα) and IL-1R8 and transmitting anti-inflammatory signals, as well as intracellularly by interacting with Smad3, entering the nucleus, and inhibiting the transcription of pro-inflammatory genes. Consequently, IL-37 is linked to IL-18, which plays a role in the pathogenesis of atopic dermatitis (AD), consistent with our studies. Some isoforms of IL-37 are expressed by keratinocytes, monocytes, and other skin immune cells. IL-37 has been found to modulate the skewed T helper 2 (Th2) inflammation that is fundamental to the pathogenesis of AD. This review provides an up-to-date summary of the function of IL-37 in modulating the immune system and analyses its potential role in the pathogenesis of AD. Moreover, it speculates on IL-37's hypothetical value as a therapeutic target in the treatment of AD.

Review of microbiota gut brain axis and innate immunity in inflammatory and infective diseases

The microbiota gut brain (MGB) axis has been shown to play a significant role in the regulation of inflammatory and infective diseases. Exploring the structure and communication mode of MGB axis is crucial for understanding its role in diseases, and studying the signaling pathways and regulatory methods of MGB axis regulation in diseases is also of profound significance for future clinical research. This article reviews the composition, communication mechanism of MGB axis and its role in inflammatory and infective diseases, including Parkinson's disease (PD), Alzheimer's disease (AD), multiple sclerosis (MS), autism spectrum disorder (ASD), depression, psoriasis, irritable bowel syndrome (IBS), and inflammatory bowel diseases (IBD). In addition, our investigation delved into the regulatory functions of the inflammasome, IFN-I, NF-κB, and PARK7/DJ-1 innate immune signaling pathway in the context of inflammatory and infective diseases. Ultimately, we discussed the efficacy of various interventions, including fecal microbiota transplantation (FMT), antibiotics, probiotics, prebiotics, synbiotics, and postbiotics, in the management of inflammatory and infective diseases. Understanding the role and mechanism of the MGB axis might make positive effects in the treatment of inflammatory and infective diseases.

Regulatory Mechanism of the IL-33-IL-37 Axis via Aryl Hydrocarbon Receptor in Atopic Dermatitis and Psoriasis

Interleukin (IL)-33 and IL-37 have been identified as novel cytokines involved in various inflammatory diseases. However, their specific roles remain largely unknown. Recent studies have shown that IL-33, which triggers inflammation, and IL-37, which suppresses it, cooperatively regulate the balance between inflammation and anti-inflammation. IL-33 and IL-37 are also deeply involved in the pathogenesis of inflammatory skin diseases such as atopic dermatitis (AD) and psoriasis. Furthermore, a signaling pathway by which aryl hydrocarbon receptor (AHR), a receptor for dioxins, regulates the expression of IL-33 and IL-37 has been revealed. Here, we outline recent findings on the mechanisms regulating IL-33 and IL-37 expression in AD and psoriasis. IL-33 expression is partially dependent on mitogen-activated protein kinase (MAPK) activation, and IL-37 has a role in suppressing MAPK in human keratinocytes. Furthermore, IL-33 downregulates skin barrier function proteins including filaggrin and loricrin, thereby downregulating the expression of IL-37, which colocalizes with these proteins. This leads to an imbalance of the IL-33-IL-37 axis, involving increased IL-33 and decreased IL-37, which may be associated with the pathogenesis of AD and psoriasis. Therefore, AHR-mediated regulation of the IL-33-IL-37 axis may lead to new therapeutic strategies for the treatment of AD and psoriasis.

Interleukin-37 inhibits desmoglein-3 endocytosis and keratinocyte dissociation via upregulation of Caveolin-1 and inhibition of the STAT3 pathway

BACKGROUND

Pemphigus vulgaris (PV) is a potentially fatal autoimmune bullous disease primarily caused by acantholysis of keratinocytes attributed to pathogenic desmoglein-3 (Dsg3) autoantibodies. Interleukin-37 (IL-37) reportedly plays important roles in a variety of autoimmune diseases, but its role in PV is not clear.

OBJECTIVES

To investigate whether IL-37 plays a role in the occurrence and progression of PV.

METHODS

HaCaT keratinocytes were stimulated with anti-Dsg3 antibody to establish an in vitro PV model, which was defined as anti-Dsg3 group. Cells incubated with medium without anti-Dsg3 treatment were used as control. IL-37 was cultured with these cells infected with or without lentiviral vector shRNA-Caveolin-1 (sh-Cav-1-LV). Cell dissociation assay and immunocytofluorescence were performed to assess keratinocyte dissociation, keratin retraction and Dsg3 endocytosis. Real-time PCR was used to detect the mRNA level of Cav-1, and western blot was used to determine the protein expression of Cav-1, Dsg3, STAT3 and phosphorylated-STAT3 (p-STAT3).

RESULTS

The anti-Dsg3 group showed more cell debris, increased keratin retraction, increased Dsg3 endocytosis, reduced Cav-1 expression and co-localization than the control group, while IL-37 treatment neutralized all of these changes. Interestingly, Cav-1 knockdown supressed the inhibitory effect of IL-37 on keratinocyte dissociation and Dsg3 internalization. The protein expression of p-STAT3 was increased in keratinocytes of the PV model but decreased by IL-37. Re-activation of the STAT3 pathway by colivelin supressed the inhibitory effect of IL-37 on keratinocyte dissociation and Dsg3 internalization, along with upregulation of Cav-1 and Dsg3.

CONCLUSIONS

IL-37 inhibited keratinocyte dissociation and Dsg3 endocytosis in an in vitro PV model through the upregulating Cav-1 and inhibiting STAT3 pathway.

IL-36α inhibits melanoma by inducing pro-inflammatory polarization of macrophages

Interleukin-36α (IL-36α) is essential for various inflammatory conditions, such as psoriasis and rheumatoid arthritis, whereas its role in tumor immunity is unclear. In this study, it was demonstrated that IL-36α could activate the NF-κB and MAPK signaling pathways in macrophages, leading to the expression of IL-1β, IL-6, TNF-α, CXCL1, CXCL2, CXCL3, CXCL5 and iNOS. Importantly, IL-36α has significant antitumor effects, altering the tumor microenvironment and promoting the infiltration of MHC IIhigh macrophages and CD8+ T cells while decreasing the levels of monocyte myeloid-derived suppressor cells, CD4+ T cells and regulatory T cells. This ultimately results in the inhibition of tumor growth and migration. Furthermore, IL-36α synergized with the PD-L1 antibody increased the immune cells infiltration and enhanced the anti-tumor effect of the PD-L1 antibody on melanoma. Collectively, this study reveals a new role for IL-36α in promoting anti-tumor immune responses in macrophages and suggests its potential for cancer immunotherapy.

Challenges and Future Trends in the Treatment of Psoriasis

Psoriasis is a chronic inflammatory skin disorder, and current treatments include topical therapies, phototherapy, systemic immune modulators, and biologics, aiming to alleviate symptoms and improve quality of life. However, challenges persist, such as adverse effects, treatment resistance, high costs, and variability in response among individuals. The future of psoriasis treatment shows promising emerging trends. New biologic agents targeting novel pathways, such as interleukin 23 inhibitors like mirikizumab, offer enhanced efficacy. Small molecule inhibitors like RORγt inhibitors and ROCK2 inhibitors provide additional treatment options. Combination therapies, including biologics with methotrexate, may improve treatment response. Advancements in topical treatments utilizing microneedles and nanoparticle-based carriers can enhance drug delivery and improve therapeutic outcomes. Biomarkers and multi-omics technologies hold potential for personalized treatment approaches, thus aiding in diagnosis, predicting treatment response, and guiding therapeutic decisions. Collaboration among researchers, clinicians, and industry stakeholders is crucial to translating these scientific breakthroughs into clinical practice. By addressing current challenges and exploring these promising trends, we can optimize psoriasis management and improve the lives of those affected by this chronic condition.

Microbiota and IL-33/31 Axis Linkage: Implications and Therapeutic Perspectives in Atopic Dermatitis and Psoriasis

Microbiome dysbiosis and cytokine alternations are key features of atopic dermatitis (AD) and psoriasis (PsO), two of the most prevalent and burdensome pruritic skin conditions worldwide. Interleukin (IL)-33 and IL-31 have been recognized to be major players who act synergistically in the pathogenesis and maintenance of different chronic inflammatory conditions and pruritic skin disorders, including AD and PsO, and their potential role as therapeutic targets is being thoroughly investigated. The bidirectional interplay between dysbiosis and immunological changes has been extensively studied, but there is still debate regarding which of these two factors is the actual causative culprit behind the aetiopathological process that ultimately leads to AD and PsO. We conducted a literature review on the Pubmed database assessing articles of immunology, dermatology, microbiology and allergology with the aim to strengthen the hypothesis that dysbiosis is at the origin of the IL-33/IL-31 dysregulation that contributes to the pathogenesis of AD and PsO. Finally, we discussed the therapeutic options currently in development for the treatment of these skin conditions targeting IL-31, IL-33 and/or the microbiome.

High Heme and Low Heme Oxygenase-1 Are Associated with Mast Cell Activation/Degranulation in HIV-Induced Chronic Widespread Pain

An overwhelming number of people with HIV (PWH) experience chronic widespread pain (CWP) throughout their lifetimes. Previously, we demonstrated that PWH with CWP have increased hemolysis and attenuated heme oxygenase 1 (HO-1) levels. HO-1 degrades reactive, cell-free heme into antioxidants like biliverdin and carbon monoxide (CO). We found that high heme or low HO-1 caused hyperalgesia in animals, likely through multiple mechanisms. In this study, we hypothesized that high heme or low HO-1 caused mast cell activation/degranulation, resulting in the release of pain mediators like histamine and bradykinin. PWH who self-report CWP were recruited from the University of Alabama at Birmingham HIV clinic. Animal models included HO-1-/- mice and hemolytic mice, where C57BL/6 mice were injected intraperitoneally with phenylhydrazine hydrochloride (PHZ). Results demonstrated that plasma histamine and bradykinin were elevated in PWH with CWP. These pain mediators were also high in HO-1-/- mice and in hemolytic mice. Both in vivo and in vitro (RBL-2H3 mast cells), heme-induced mast cell degranulation was inhibited by treatment with CORM-A1, a CO donor. CORM-A1 also attenuated mechanical and thermal (cold) allodynia in hemolytic mice. Together, the data suggest that mast cell activation secondary to high heme or low HO-1 seen in cells and animals correlates with elevated plasma levels of heme, histamine, and bradykinin in PWH with CWP.

Circ_0082476 targets miR-138-5p to promote proliferation, invasion, migration and inflammation in IL-22-treated human keratinocytes by upregulating BRD4

BACKGROUND

Circular RNAs (circRNAs) are implicated in the disease progression via acting as sponges of microRNAs (miRNAs) to regulate gene expression. The purpose of this study was to analyze the involvement of circ_0082476 in Interleukin-22 (IL-22)-induced psoriasis.

METHODS

Expression detection for circ_0082476, microRNA-424-5p (miR-138-5p) or toll-like receptor (BRD4) was completed using reverse transcription-quantitative polymerase chain reaction assay. Cell Counting Kit-8 assay and EdU assay were used for analysis of cell viability and proliferation, respectively. Cell invasion and migration abilities were assessed through transwell assay and wound healing assay. The protein expression was examined via western blot. Inflammatory reaction was determined via Enzyme-linked immunosorbent assay. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were conducted for target binding research.

RESULTS

Circ_0082476 was significantly elevated in psoriasis patients and IL-22-treated keratinocytes (HaCaT). Knockdown of circ_0082476 reduced cell proliferation, invasion and migration in IL-22-treated HaCaT cells. Circ_0082476 induced sponge effect on miR-138-5p. Circ_0082476 regulated IL-22-induced cell injury through targeting miR-138-5p. BRD4 was confirmed as a target of miR-138-5p, and miR-138-5p relieved IL-22-induced cell dysfunction by the direct downregulation of BRD4. BRD4 was positively regulated by circ_0082476 via sponging miR-138-5p.

CONCLUSION

These findings disclosed that circ_0082476 facilitated the IL22-induced epidermis cell injury in psoriasis through the upregulation of BRD4 via binding to miR-138-5p.

Activation of Mast Cells by Neuropeptides: The Role of Pro-Inflammatory and Anti-Inflammatory Cytokines

Mast cells (MCs) are tissue cells that are derived from bone marrow stem cells that contribute to allergic reactions, inflammatory diseases, innate and adaptive immunity, autoimmunity, and mental disorders. MCs located near the meninges communicate with microglia through the production of mediators such as histamine and tryptase, but also through the secretion of IL-1, IL-6 and TNF, which can create pathological effects in the brain. Preformed chemical mediators of inflammation and tumor necrosis factor (TNF) are rapidly released from the granules of MCs, the only immune cells capable of storing the cytokine TNF, although it can also be produced later through mRNA. The role of MCs in nervous system diseases has been extensively studied and reported in the scientific literature; it is of great clinical interest. However, many of the published articles concern studies on animals (mainly rats or mice) and not on humans. MCs are known to interact with neuropeptides that mediate endothelial cell activation, resulting in central nervous system (CNS) inflammatory disorders. In the brain, MCs interact with neurons causing neuronal excitation with the production of neuropeptides and the release of inflammatory mediators such as cytokines and chemokines. This article explores the current understanding of MC activation by neuropeptide substance P (SP), corticotropin-releasing hormone (CRH), and neurotensin, and the role of pro-inflammatory cytokines, suggesting a therapeutic effect of the anti-inflammatory cytokines IL-37 and IL-38.

Suprabasin-derived polypeptides: SBSN(50-63) induces inflammatory response via TLR4-mediated mast cell activation

Psoriasis is a chronic, relapsing, immune-mediated, and papulosquamous skin disorder. Excessive mast cell activation, in psoriatic lesions, contributes to inflammation. Various endogenous peptides can participate in the pathogenesis of inflammatory diseases by activating mast cells. Suprabasin (SBSN) is expressed in multiple epithelial tissues and it regulates the normal epidermal barrier function. We have recently shown that suprabasin-derived polypeptides, SBSN(50-63), are significantly increased in psoriatic lesions, through differential peptide analysis. This study was conducted to clarify whether SBSN(50-63) plays a pivotal role in activating mast cells and mediating proinflammatory cytokines and chemokines production in psoriasis. The increased expression of SBSN in psoriatic lesions was confirmed by bioinformatics analysis, PCR and ELISA. Wild-type mice injected subcutaneously with SBSN(50-63) exhibited infiltration of inflammatory cells and the release of cytokines in vivo. SBSN(50-63) stimulated mouse primary mast cells (MPMC) and the laboratory of allergic disease 2 (LAD2) human mast cells to produce more inflammatory mediators than the control group, which were measured ex vivo and in vitro. Toll-like receptor 4 was identified as the receptor of SBSN on mast cells by molecular docking analysis, molecular dynamics simulation, and siRNA transfection. Collectively, SBSN(50-63) could activate mast cells through TLR4, which may increase the inflammatory response in psoriasis.

Neuroblast Differentiation-Associated Protein Derived Polypeptides: AHNAK(5758-5775) Induces Inflammation by Activating Mast Cells via ST2

Psoriasis is a chronic inflammatory skin disease. Mast cells are significantly increased and activated in psoriatic lesions and are involved in psoriatic inflammation. Some endogenous substances can interact with the surface receptors of mast cells and initiate the release of downstream cytokines that participate in inflammatory reactions. Neuroblast differentiation-associated protein (AHNAK) is mainly expressed in the skin, esophagus, kidney, and other organs and participates in various biological processes in the human body. AHNAK and its derived peptides have been reported to be involved in the activation of mast cells and other immune processes. This study aimed to investigate whether AHNAK (5758-5775), a neuroblast differentiation-associated protein-derived polypeptide, could be considered a new endogenous substance in psoriasis patients, which activates mast cells and induces the skin inflammatory response contributing to psoriasis. Wild-type mice were treated with AHNAK(5758-5775) to observe the infiltration of inflammatory cells in the skin and cytokine release in vivo. The release of inflammatory mediators by mouse primary mast cells and the laboratory of allergic disease 2 (LAD2) human mast cells was measured in vitro. Molecular docking analysis, molecular dynamics simulation, and siRNA transfection were used to identify the receptor of AHNAK(5758-5775). AHNAK(5758-5775) could cause skin inflammation and cytokine release in wild-type mice and activated mast cells in vitro. Moreover, suppression of tumorigenicity 2 (ST2) might be a key receptor mediating AHNAK(5758-5775)'s effect on mast cells and cytokine release. We propose a novel polypeptide, AHNAK(5758-5775), which induces an inflammatory reaction and participates in the occurrence and development of psoriasis by activating mast cells.

Immunopathogenesis of Atopic Dermatitis: Focus on Interleukins as Disease Drivers and Therapeutic Targets for Novel Treatments

Atopic dermatitis is a chronic, recurrent inflammatory skin disorder manifesting by eczematous lesions and intense pruritus. Atopic dermatitis develops primarily as a result of an epidermal barrier defect and immunological imbalance. Advances in understanding these pathogenetic hallmarks, and particularly the complex role of interleukins as atopic dermatitis drivers, resulted in achieving significant therapeutic breakthroughs. Novel medications involve monoclonal antibodies specifically blocking the function of selected interleukins and small molecules such as Janus kinase inhibitors limiting downstream signaling to reduce the expression of a wider array of proinflammatory factors. Nevertheless, a subset of patients remains refractory to those treatments, highlighting the complexity of atopic dermatitis immunopathogenesis in different populations. In this review, we address the immunological heterogeneity of atopic dermatitis endotypes and phenotypes and present novel interleukin-oriented therapies for this disease.

IL-33 and IL-37: A Possible Axis in Skin and Allergic Diseases

Interleukin (IL)-37 and IL-33 are among the latest cytokines identified, playing a role in several inflammatory conditions, spanning from systemic conditions to tumors to localized diseases. As newly discovered interleukins, their role is still scarcely understood, but their potential role as therapeutic targets or disease activity markers suggests the need to reorganize the current data for a better interpretation. The aim of this review is to collect and organize data produced by several studies to create a complete picture. The research was conducted on the PubMed database, and the resulting articles were sorted by title, abstract, English language, and content. Several studies have been assessed, mostly related to atopic dermatitis and immunologic pathways. Collective data demonstrates a pro-inflammatory role of IL-33 and an anti-inflammatory one for IL-37, possibly related to each other in an IL-33/IL-37 axis. Although further studies are needed to assess the safety and plausibility of targeting these two interleukins for patients affected by skin conditions, the early results indicate that both IL-33 and IL-37 represent markers of disease activity.

Mast Cells and Interleukins

Mast cells play a critical role in inflammatory diseases and tumor growth. The versatility of mast cells is reflected in their ability to secrete a wide range of biologically active cytokines, including interleukins, chemokines, lipid mediators, proteases, and biogenic amines. The aim of this review article is to analyze the complex involvement of mast cells in the secretion of interleukins and the role of interleukins in the regulation of biological activities of mast cells.

Combining network pharmacology, RNA-seq, and metabolomics strategies to reveal the mechanism of Cimicifugae Rhizoma - Smilax glabra Roxb herb pair for the treatment of psoriasis

BACKGROUND

Psoriasis is a prevalent chronic inflammatory skin condition marked by immune cell infiltration and keratinocyte abnormal proliferation. Cimicifugae Rhizoma - Smilax glabra Roxb (CS) herb pair, the main component of Shengma Detoxification Decoction, has been proven effective for the treatment of psoriasis. However, the mechanism is yet to be deciphered.

PURPOSE

To explore the mechanism of CS for the treatment of psoriasis.

METHODS

The imiquimod-induced psoriasis-like lesion mouse model was used to identify the targets and the molecular mechanisms of CS. Network pharmacology combined with RNA-seq strategy was employed to predict the targets and mechanisms of CS for psoriasis. Metabolomics approaches were used to demonstrate the complexity of CS for the treatment of psoriasis. Finally, a compound-response-enzyme-gene network was constructed based on the multi-omics results to elucidate potential connections.

RESULTS

The CS herb pair could significantly improve psoriatic lesions and reduce the inflammatory cell infiltration and proliferation of keratinocytes in skin lesions. Network pharmacology predicted that TNF, JNK, IL-6, and IL-1β could be potential targets. RNA-seq data revealed that CS could significantly regulate genes and signaling pathways associated with Th17 responses, such as IL-36, IL-1β, CCl2, CXCL16, keratin 14, keratin 5, and antimicrobial peptides S100A8 and S100A9 well as MAPK, mTOR, and other signaling pathways. Further experimental data validated that CS treatment remarkably reduced the expression of inflammatory cytokines and factors, such as CCL2, CCL7, IL1F6, IL-17, IL-23, IL-1β, TNF-α, and IL-6, and inhibited the phosphorylation of p38 and ERK1/2. This indicated that CS exerts its therapeutic effect by inhibiting the MAPK signaling pathways. In addition, metabolomic analyses demonstrated that CS treatment improved seven metabolic pathways, these included phenylalanine, tyrosine, pyruvate metabolism, carnitine metabolism, etc. Four key metabolites (L-Arginine, L-Phenylalanine, L-Carnitine, O-Acetylcarnitine) and nine differential genes (CMA1, PCBD2, TPSAB1, TPSB2, etc.) were identified that affected amino acid metabolism, carnitine metabolism, and other pathways contributing to the infiltration of Th17 cells in psoriatic lesions.

CONCLUSION

CS could alleviate IMQ-induced psoriasis-like dermatitis by reducing the expression of cytokines and chemokines mediated by the MAPK pathway, and improved amino acid and carnitine metabolism in vivo. Our study is the first to demonstrate the complex mechanism of CS for the treatment of psoriasis and provides a new paradigm to elucidate the pharmacological effects of Traditional Chinese Medicine (TCM) drugs for psoriasis from multiple perspectives.

Further Understanding of Neuro-Immune Interactions in Allergy: Implications in Pathophysiology and Role in Disease Progression

The complicated interaction between the central and the autonomic (sympathetic, parasympathetic, and enteric) nervous systems on the one hand and the immune system and its components, on the other hand, seems to substantially contribute to allergy pathophysiology, uncovering an under-recognized association that could have diagnostic and therapeutic potentials. Neurons connect directly with and regulate the function of many immune cells, including mast cells, the cells that have a leading role in allergic disorders. Proinflammatory mediators such as cytokines, neurotrophins, chemokines, and neuropeptides are released by immune cells, which stimulate sensory neurons. The release of neurotransmitters and neuropeptides caused by the activation of these neurons directly impacts the functional activity of immune cells and vice versa, playing a decisive role in this communication. Successful application of Pavlovian conditioning in allergic disorders supports the existence of a psychoneuroimmunological interplay in classical allergic hypersensitivity reactions. Activation of neuronal homeostatic reflexes, like sneezing in allergic rhinitis, coughing in allergic asthma, and vomiting in food allergy, offers additional evidence of a neuroimmunological interaction that aims to maintain homeostasis. Dysregulation of this interaction may cause overstimulation of the immune system that will produce profound symptoms and exaggerated hemodynamic responses that will lead to severe allergic pathophysiological events, including anaphylaxis. In this article, we have systematically reviewed and discussed the evidence regarding the role of the neuro-immune interactions in common allergic clinical modalities like allergic rhinitis, chronic rhinosinusitis, allergic asthma, food allergy, atopic dermatitis, and urticaria. It is essential to understand unknown – to most of the immunology and allergy experts – neurological networks that not only physiologically cooperate with the immune system to regulate homeostasis but also pathogenetically interact with more or less known immunological pathways, contribute to what is known as neuroimmunological inflammation, and shift homeostasis to instability and disease clinical expression. This understanding will provide recognition of new allergic phenotypes/endotypes and directions to focus on specialized treatments, as the era of personalized patient-centered medicine, is hastening apace.

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.

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.

The potency of common proinflammatory cytokines measurement for revealing the risk and severity of anxiety and depression in psoriasis patients

Objective

Proinflammatory cytokines mediate anxiety and depression in various ways, such as immunity, inflammation, and the hypothalamic–pituitary–adrenal axis. This study intended to further explore the linkage of common proinflammatory cytokine levels with anxiety and depression in psoriasis patients.

Methods

Totally, 150 psoriasis patients and 50 healthy controls (HCs) were included; the serum samples were collected, then common proinflammatory cytokines were measured by ELISA. Hospital Anxiety and Depression Scale (HADS) was assessed.

Results

HADS‐anxiety (HADS‐A) score, HADS‐depression (HADS‐D) score, TNF‐α, IL‐1β, IL‐6, IL‐12, IL‐17A, and IL‐23 were all increased in psoriasis patients compared to HCs (all p < 0.05). In psoriasis patients, TNF‐α (p = 0.001), IL‐12 (p = 0.035), and IL‐17A (p < 0.001), but not IL‐1β (p = 0.255), IL‐6 (p = 0.248), and IL‐23 (p = 0.216), were positively linked to HADS‐A score. Meanwhile, TNF‐α (p = 0.007) and IL‐17A (p = 0.007) were enhanced in psoriasis patients with anxiety in contrast to those without anxiety; whereas IL‐1β (p = 0.178), IL‐6 (p = 0.360), IL‐12 (p = 0.239), and IL‐23 (p = 0.450) were not different. TNF‐α (p < 0.001), IL‐1β (p = 0.013), Il‐17A (p < 0.001), and IL‐23 (p = 0.023), but not IL‐6 (p = 0.143) and IL‐12 (p = 0.158), were positively linked to HADS‐D score. Concurrently, TNF‐α (p = 0.015), IL‐17A (p < 0.001), and IL‐23 (p = 0.017) were climbed in psoriasis patients with depression by comparison to those without depression; whereas IL‐1β (p = 0.113), IL‐6 (p = 0.237), IL‐12 (p = 0.660) did not differ.

Conclusion

TNF‐α, IL‐17A, and IL‐23 increments reflect anabatic anxiety and depression in psoriasis patients, uncovering the potency of proinflammatory cytokines measurement for monitoring or even preventing psoriasis patients' anxiety and depression.

Unmet Medical Needs in Chronic, Non-communicable Inflammatory Skin Diseases

An estimated 20-25% of the population is affected by chronic, non-communicable inflammatory skin diseases. Chronic skin inflammation has many causes. Among the most frequent chronic inflammatory skin diseases are atopic dermatitis, psoriasis, urticaria, lichen planus, and hidradenitis suppurativa, driven by a complex interplay of genetics and environmental factors. Autoimmunity is another important cause of chronic skin inflammation. The autoimmune response may be mainly T cell driven, such as in alopecia areata or vitiligo, or B cell driven in chronic spontaneous urticaria, pemphigus and pemphigoid diseases. Rare causes of chronic skin inflammation are autoinflammatory diseases, or rheumatic diseases, such as cutaneous lupus erythematosus or dermatomyositis. Whilst we have seen a significant improvement in diagnosis and treatment, several challenges remain. Especially for rarer causes of chronic skin inflammation, early diagnosis is often missed because of low awareness and lack of diagnostics. Systemic immunosuppression is the treatment of choice for almost all of these diseases. Adverse events due to immunosuppression, insufficient therapeutic responses and relapses remain a challenge. For atopic dermatitis and psoriasis, a broad spectrum of innovative treatments has been developed. However, treatment responses cannot be predicted so far. Hence, development of (bio)markers allowing selection of specific medications for individual patients is needed. Given the encouraging developments during the past years, we envision that many of these challenges in the diagnosis and treatment of chronic inflammatory skin diseases will be thoroughly addressed in the future.

Eosinophil count and tumor necrosis factor α in response to phototherapy treatment of neonatal hyperbilirubinemia: a cross sectional study

Background

Phototherapy (PT) is the most often utilized technique for treating and preventing severe hyperbilirubinemia in the term and preterm newborns. PT's proven benefit is that it decreases the requirement for exchange transfusions. To investigate the effect of PT on allergic response mediators in neonates with hyperbilirubinemia treated by PT, eosinophil counts and tumor necrosis factor alfa levels have been assessed.

Methods

This cross-sectional study included 100 full-term infants with indirect hyperbilirubinemia in the first two weeks of life who were indicated for PT. They were investigated by tumor necrosis factor α and eosinophil counts before and 72 h after starting PT. The used tests were paired with Student’s t-test and Pearson coefficient.

Results

Relative and absolute eosinophil counts and tumor necrosis factor alfa were significantly higher after PT than before (p < 0.001). There was a significant positive correlation between total serum bilirubin and both tumor necrosis factor alfa and eosinophil % (r = 0.442 and r = 0.362, respectively, P < 0.001) before PT. There was a significant positive correlation between total serum bilirubin and both eosinophil count and eosinophil % (r = 0.281and r = 0.339), respectively (P < 0.001) after PT. There was a significant positive correlation between both tumor necrosis factor alfa and eosinophil % after PT (r = 0.545, P < 0.001).

Conclusions

Serum tumor necrosis factor-alpha and eosinophilic count increased after treatment of neonatal hyperbilirubinemia by PT, which indicates an allergic response to PT in neonates.

The Multifaceted Roles of Mast Cells in Immune Homeostasis, Infections and Cancers

Mast cells (MCs) play important roles in normal immune responses and pathological states. The location of MCs on the boundaries between tissues and the external environment, including gut mucosal surfaces, lungs, skin, and around blood vessels, suggests a multitude of immunological functions. Thus, MCs are pivotal for host defense against different antigens, including allergens and microbial pathogens. MCs can produce and respond to physiological mediators and chemokines to modulate inflammation. As long-lived, tissue-resident cells, MCs indeed mediate acute inflammatory responses such as those evident in allergic reactions. Furthermore, MCs participate in innate and adaptive immune responses to bacteria, viruses, fungi, and parasites. The control of MC activation or stabilization is a powerful tool in regulating tissue homeostasis and pathogen clearance. Moreover, MCs contribute to maintaining the homeostatic equilibrium between host and resident microbiota, and they engage in crosstalk between the resident and recruited hematopoietic cells. In this review, we provide a comprehensive overview of the functions of MCs in health and disease. Further, we discuss how mouse models of MC deficiency have become useful tools for establishing MCs as a potential cellular target for treating inflammatory disorders.

Therapeutic potential of targeting IL-1 family cytokines in chronic inflammatory skin diseases

The interleukin-1 (IL-1) family of cytokines is a central regulator of a myriad of immunological responses. It comprises several cytokines, including those belonging to the IL-1, IL-36 and IL-18 subfamilies, as well as IL-33. The IL-1 family primarily plays a role in orchestrating innate immune responses but also in adaptive immunity. Increased interest in the IL-1 family occurred following the discovery that dysregulation of IL-1 signalling underlies the pathogenesis of several monogenic auto-inflammatory diseases, characterized by sterile inflammation involving the skin and other organs. This also provided increased understanding of the role of innate immunity and the IL-1 family in polygenic auto-inflammatory skin conditions, such as neutrophilic dermatoses, as well as in some of the most common chronic inflammatory skin diseases, such as psoriasis or hidradenitis suppurativa. Several therapeutic agents have been developed to inhibit the IL-1 family members and their signalling pathways. These have shown therapeutic efficacy in several chronic inflammatory skin disorders. The aim of this review is to thoroughly describe the consequences of pathological dysregulation of IL-1, IL-33, IL-36, IL-18 pathways in dermatological conditions and to provide a forward-looking update on therapeutic strategies targeting signalling by IL-1 family cytokines.

Immunobiological Properties and Clinical Applications of Interleukin-38 for Immune-Mediated Disorders: A Systematic Review Study

Exponential growth in the usage of "cytokines" (as seroimmunobiomarkers) has facilitated more accurate prognosis, early diagnosis, novel, and efficient immunotherapeutics. Numerous studies have reported immunopathophysiological and immunopathological processes of interleukin-38 (IL-38). Therefore, in this systematic review article, the authors aimed to present an updated comprehensive overview on the immunobiological mechanisms, diagnostic, and immune gene-based therapeutic potentials of IL-38. According to our inclusion and exclusion criteria, a total of 216 articles were collected from several search engines and databases from the January 2012 to July 2021 time interval by using six main keywords. Physiologic or pathologic microenvironments, optimal dosage, and involved receptors affect the functionalities of IL-38. Alterations in serum levels of IL-38 play a major role in the immunopathogenesis of a wide array of immune-mediated disorders. IL-38 shows anti-inflammatory activities by reduction or inhibition of pro-inflammatory cytokines, supporting the therapeutic aspects of IL-38 in inflammatory autoimmune diseases. According to the importance of pre-clinical studies, it seems that manipulation of the immune system by immunomodulatory properties of IL-38 can increase the accuracy of diagnosis, and decipher optimal clinical outcomes. To promote our knowledge, more collaboration is highly recommended among laboratory scientists, internal/infectious diseases specialists, oncologists, immunologists, diseases-specific biomarkers scientists, and basic medical researchers.