Role of IL-22 in homeostasis and diseases of the skin

Th22 cells promote the transition from homeostatic to reactive microglia in diabetic encephalopathy

BACKGROUND

Diabetic encephalopathy (DE) is one of the most serious complications of diabetes mellitus (DM), and its pathogenesis has not yet been clarified. Th22 cells are a newly discovered class of CD4+ T cells that play important roles in inflammatory, autoimmune and infectious diseases. However, it is unclear whether Th22 cells are involved in the pathogenesis of DE.

METHODS

We established a T2DM mouse model in vivo and cocultured Th22 cells with microglia under high glucose (HG) conditions in vitro. Cognitive dysfunction was evaluated using the Morris water maze (MWM) test; blood‒brain barrier (BBB) integrity was evaluated using the Evans blue (EB) extravasation assay; Th22 cells and IL-22 receptors were detected by immunofluorescence; and IL-1β, TNF-α, iNOS, CD86, Arg-1, and CD206 protein expression was measured by Western Blot (WB) analysis.

RESULTS

Th22 cells passed through the BBB into the hippocampus and secreted interleukin-22 (IL-22), and the mice subsequently exhibited decreased learning and memory abilities. In the DE model, IL-22 promoted the transformation of homeostatic microglia into reactive microglia as well as the inflammatory response. Additionally, coculture of Th22 cells with BV2 microglia cultured under HG conditions increased the production of proinflammatory cytokines, and the microglia showed reactive changes. Mechanistically, IL-22Rα1 acted as a ligand, and IL-22 bound to IL-22Rα1 on microglia to drive primary microglia-induced inflammatory responses. Interestingly, interleukin-22 binding protein (IL-22BP) directly binds to IL-22Rα1 on microglia to inhibit the proinflammatory effects of IL-22.

CONCLUSION

Th22 cells secrete IL-22 after passing through the BBB into the hippocampus and promote the transformation of homeostatic microglia into reactive microglia, which induces an inflammatory response, exacerbates learning and memory impairment and cognitive deficits, and contributes to and accelerates the development of DE.

IL-22BP Modulates Injury in Acute Pancreatitis but Delays Tissue Recovery in Chronic Pancreatitis

BACKGROUND & AIMS

In acute pancreatitis, interleukin (IL)-22 signaling is increased, whereas overall expression of the cytokine paradoxically drops, suggesting an additional level of control. Here, we investigate the regulation of IL-22 signaling by its soluble neutralizing receptor interleukin-22 binding protein (IL-22BP) in the context of both acute and chronic pancreatitis.

METHODS

Cerulein was used to induce acute and chronic pancreatitis in both wild-type mice and IL-22BP knockout mice. Histology, multiplex immunofluorescence and flow cytometry were performed to compare differences in tissue injury, recovery, fibrosis, and inflammation at various times of recovery.

RESULTS

Loss of IL-22BP resulted in increased canonical IL-22 signaling and the expression of the anti-autophagy protein Bcl-XL. This was associated with decreased severity of acute pancreatitis, as evidenced by lower serum amylase and tissue injury. In chronic pancreatitis, IL-22BP expression was induced in the inflammatory and recovery phases and genetic deletion resulted in unchecked IL-22 signaling, as demonstrated by persistent p-Stat3 signaling and proliferation of both epithelial cells and fibroblasts. Loss of IL-22BP increased myeloid cell infiltration, which persisted throughout recovery. Mechanistically, IL-22 activity forced persistent acinar to ductal metaplasia and delayed tissue recovery.

CONCLUSIONS

IL-22BP plays an important role in modulating IL-22 activity during tissue injury and recovery after pancreatitis. Loss of IL-22BP attenuated acute pancreatitis but promoted chronic fibrosis and inflammation through uncontrolled IL-22 signaling and subsequent deleterious effects on epithelial cells, fibroblasts, and immune infiltration.

NLRC3 affects the development of psoriasis by modulating the NF-κB signaling pathway mediated inflammatory response through its interaction with TRAF6

OBJECTIVE

The function and mechanism of NOD-like receptor family CARD-containing 3 (NLRC3) in psoriasis are not yet reported, even though it plays a crucial role in innate and adaptive immunity by inhibiting inflammation. Therefore, this research aims to investigate the role and mechanism of NLRC3 in psoriasis.

METHODS

HaCaT cells were induced to form a psoriasis cell model using 20 ng/mL IL-1β, 20 ng/mL IL-17A, 20 ng/mL IL-23, 50 ng/mL TNF-α, and 20 ng/mL oncostatin M. Cell Counting Kit-8 (CCK-8) assay and flow cytometry were assessed to determine the proliferation, cell cycle, and apoptosis of HaCaT cells. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was utilized to measure the knockdown efficiency of NLRC3 and TRAF6 interfering RNA in HaCaT cells. Western blot analysis was performed to determine the expression levels of NLRC3, TRAF6, and proteins associated with the NF-κB signaling pathway. A mouse model of psoriasis-like dermatitis was established by evenly applying miquimod cream (62.5 mg/day) to both ears. Hematoxylin-eosin staining was used to measure ear thickness and inflammatory infiltrates in mice. Histological analysis, immunohistochemistry, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL were performed to detect cell proliferation and apoptosis. Interactions between NLRC3 and TRAF6 were predicted using the STRING database (https://cn.string-db.org/). Co-Immunoprecipitation was used to confirm interactions between NLRC3 and TRAF6. Ubiquitination of TRAF6 was assessed by Western blot.

RESULTS

Knockdown of NLRC3 expression promoted cell proliferation and inhibited cell apoptosis in HaCaT cells. In vivo, knockdown of NLRC3 expression significantly increased the infiltration of inflammatory cells and the proliferation of Ki-67 positive cells within mouse ear epidermis, while decreasing the number of apoptotic cells. NLRC3 interacted with TRAF6 and influenced its K63 ubiquitination level. Knockdown of TRAF6 expression resulted in increased cell proliferation and decreased cell apoptosis in HaCaT cells. In vivo, knockdown of TRAF6 expression led to a significant increase in inflammatory cell infiltration and Ki-67 positive cells in mouse ear epidermis, and a decrease in apoptotic cells. Inhibiting the NF-κB signaling pathway alleviated the progression of psoriasis, and interfering with TRAF6 activated the NF-κB signaling axis, contributing to the onset and advancement of psoriasis.

CONCLUSION

NLRC3 affects the occurrence of psoriasis by regulating TRAF6 and influencing the NF-κB signaling axis-mediated inflammatory response. This finding offers a theoretical foundation for the treatment of psoriasis.

Integration of GWAS, QTLs and keratinocyte functional assays reveals molecular mechanisms of atopic dermatitis

Atopic dermatitis is a highly heritable and common inflammatory skin condition affecting children and adults worldwide. Multi-ancestry approaches to atopic dermatitis genetic association studies are poised to boost power to detect genetic signal and identify loci contributing to atopic dermatitis risk. Here, we present a multi-ancestry GWAS meta-analysis of twelve atopic dermatitis cohorts from five ancestral populations totaling 56,146 cases and 602,280 controls. We report 101 genomic loci associated with atopic dermatitis, including 16 loci that have not been previously associated with atopic dermatitis or eczema. Fine-mapping, QTL colocalization, and cell-type enrichment analyses identified genes and cell types implicated in atopic dermatitis pathophysiology. Functional analyses in keratinocytes provide evidence for genes that could play a role in atopic dermatitis through epidermal barrier function. Our study provides insights into the etiology of atopic dermatitis by harnessing multiple genetic and functional approaches to unveil the mechanisms by which atopic dermatitis-associated variants impact genes and cell types.

Targeting Cytokine Dysregulation in Psoriasis: The Role of Dietary Interventions in Modulating the Immune Response

Psoriasis is a chronic immune-mediated skin disease characterized by cytokine dysregulation. Pro-inflammatory mediators, including tumor necrosis factor-alpha (TNF-α), interleukin (IL)-17, and IL-23, play pivotal roles in the pathogenesis of psoriasis. Emerging evidence suggests that dietary interventions can modulate cytokine activity, providing a complementary approach to standard therapies. This narrative review examines the impact of various dietary strategies, including a Mediterranean diet, ketogenic diet, gluten-free diet, and fasting-mimicking diet, on cytokine profiles and clinical outcomes in psoriasis. Research insights reveal that dietary components such as omega-3 fatty acids, polyphenols, and short-chain fatty acids influence immune signaling pathways. These pathways include nuclear factor-kappa B (NF-κB) and Signal Transducer and Activator of Transcription 3 (STAT3). Additionally, these dietary components promote anti-inflammatory effects mediated by gut microbiota. Clinical studies demonstrate significant reductions in psoriasis severity, improved quality of life, and modulation of key cytokines associated with disease activity. Despite these advancements, significant challenges persist in effectively integrating these findings into clinical practice. These challenges include variability in patient responses, adherence issues, and the need for robust biomarkers to monitor efficacy. Future directions emphasize the potential of personalized nutrition and precision medicine approaches to optimize dietary interventions tailored to individual cytokine profiles and genetic predispositions. Integrating these strategies into psoriasis care could transform treatment paradigms by simultaneously addressing both systemic inflammation and comorbid conditions.

Interleukins in the Pathogenesis of Warts: Insight from the Last Decade-A Narrative Review

Human papillomavirus (HPV) is the etiological agent of a wide spectrum of diseases, from benign lesions to neoplasms. In most cases, in the first few years after infection, viral clearance occurs; however, in some cases, the infection remains persistent, allowing the progression of the lesions. The host immune response plays a key role in the resolution of the infection. The immune response to HPV is regulated by the dynamic interaction between numerous interleukins that exert pro- or anti-inflammatory effects. The role of interleukins in malignant lesions caused by HPV has been intensively studied, but in the case of benign lesions including warts, data are limited. This review compiles data from the last 10 years on the involvement of interleukins in the pathogenesis of warts, with the aim of providing new perspectives on this topic. Elucidating the role of interleukins will not only increase our knowledge of the pathogenesis of HPV infection but will also provide the foundation for the development of new therapies.

Cytokines, chemokines and growth factors involved in keloids pathogenesis

Keloid is a common fibrotic disease, which is difficult to treat. It often causes itching and pain, which greatly disturbs patients in their work and daily life and causing difficulties in social interaction. Its pathogenesis is not clear, but may be related to several aspects: genetic susceptibility, environmental, immunological and endocrine factors, trauma and tension. The central point of its pathogenesis is the excessive proliferation of fibroblasts, with excessive synthesis and secretion of extracellular matrix such as collagen. However, the cause of fibroblast excessive proliferation and differentiation is not clear. Immune abnormalities may play an important role, with cytokines, chemokines, growth factors, and other important immune molecules acting on fibroblasts. This paper presents a detailed and comprehensive literature review on this subject.

Filaggrinopathies-FLG/FLG2: Diagnostic Complexities and Immunotherapy

FLG and FLG2 proteins are expressed in the outer layers of the epidermis, where they are vital in epidermal differentiation and skin barrier formation. Filaggrinopathies involving dysfunctions in these proteins are associated with a spectrum of phenotypic presentations, from monogenic to multifactorial conditions. This review examines biosynthesis and function of FLG and FLG2 proteins and evaluates their molecular pathogenesis in filaggrinopathies. Moreover, genotype-phenotype correlations are assessed, emphasizing genetic diagnosis complexities and diverse immune dysregulation patterns. Finally, it examines ongoing immunotherapeutic approaches by targeting different cytokines as promising treatment options for filaggrinopathies management.

IL-22-mediated microRNA-124-3p/GRB2 axis regulates hyperproliferation and inflammatory response of keratinocytes in psoriasis

Psoriasis is an inflammatory dermatosis that features overproliferation and inflammatory reaction of keratinocytes. A study reported that IL-22 is involved in the pathogenesis of psoriasis by mediating miR-124 to regulate the expression of fibroblast growth factor receptor 2 in keratinocytes. A microRNA may target multiple target genes. Therefore, we speculate that miR-124-3p may also target other downstream genes to affect IL -22-induced keratinocyte function. A possible target gene of miR-124-3p, growth factor receptor-bound protein 2 (GRB2), was screened by analyzing the target gene databases. GRB2 expression was elevated and miR-124-3p expression was decreased in psoriatic lesions compared to psoriatic adjacent normal skins and healthy controls. We performed the following cell experiments in the IL-22-stimulated HaCaT cell model. In keratinocytes transfected with the miR-124-3p mimics, GRB2 expression was significantly lower. We analyzed the regulation of keratinocyte proliferation by GRB2 and miR-124-3p. High levels of GRB2 promoted keratinocyte proliferation and expression of Ki67, PCNA, and K16, which were inhibited by low expression of GRB2. In addition, we found that the effect of GRB2 inhibitors on the proliferation and inflammatory response of keratinocytes was dose-dependent. Finally, we investigated the influence of GRB2 on inflammatory mediators in keratinocytes with the ELISA. After low expression of GRB2, the mRNA expression and secretion of the pro-inflammatory factor were suppressed. When both GRB2 and miR-124-3p were overexpressed, the cellular overproliferation and inflammation caused by GRB2 overexpression were significantly reversed by miR-124-3p. In summary, IL-22-mediated miR-124-3p regulates keratinocyte hyperproliferation and inflammatory response by suppressing GRB2 expression in psoriasis.

Atopic dermatitis: pathogenesis and therapeutic intervention

The skin serves as the first protective barrier for nonspecific immunity and encompasses a vast network of skin-associated immune cells. Atopic dermatitis (AD) is a prevalent inflammatory skin disease that affects individuals of all ages and races, with a complex pathogenesis intricately linked to genetic, environmental factors, skin barrier dysfunction as well as immune dysfunction. Individuals diagnosed with AD frequently exhibit genetic predispositions, characterized by mutations that impact the structural integrity of the skin barrier. This barrier dysfunction leads to the release of alarmins, activating the type 2 immune pathway and recruiting various immune cells to the skin, where they coordinate cutaneous immune responses. In this review, we summarize experimental models of AD and provide an overview of its pathogenesis and the therapeutic interventions. We focus on elucidating the intricate interplay between the immune system of the skin and the complex regulatory mechanisms, as well as commonly used treatments for AD, aiming to systematically understand the cellular and molecular crosstalk in AD-affected skin. Our overarching objective is to provide novel insights and inform potential clinical interventions to reduce the incidence and impact of AD.

Monoclonal antibodies in phase II and III trials for moderate to severe atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease that significantly affects quality of life and mental health, especially in children. Traditional treatments include chemotherapeutics, topical corticosteroids, and immunomodulatory agents, but recent advances have introduced novel monoclonal antibody therapies. Through this comprehensive review paper, we aim to discuss these therapeutic options and their role in treating atopic dermatitis.

AREAS COVERED

A comprehensive search of the NIH Clinical Trials database was conducted from September 2023 to January 2024, focusing on phase 2 and 3 trials for AD treatments. Trials were filtered using keywords such as 'atopic dermatitis,' 'monoclonal antibody,' and 'phase 2/3.' Out of 25 trials analyzed, 11 were in phase 2 and 14 in phase 3. Only U.S.-based trials comparing novel therapies to placebo were included. In addition to the clinical trial database, we utilized the companies' websites and relevant abstracts to gather the latest results.

EXPERT OPINION

Currently investigated monoclonal antibodies have the ability to transform management by targeting specific mediators implicated in the inflammatory pathway of AD. The results of Phase II and III trials for monoclonal antibodies demonstrated strong therapeutic potential with significant reductions in EASI scores and represent a promising new targeted treatment option.

Harnessing IL-22 for metabolic health: promise and pitfalls

Primarily perceived as an anti-inflammatory and antimicrobial mediator in mucosa and skin, interleukin-22 (IL-22) has emerged as a pivotal metabolic regulator. Central to IL-22 signaling is its receptor, IL-22RA1. Through IL-22RA1, IL-22 orchestrates glucose homeostasis by modulating insulin secretion, reducing cellular stress in pancreatic islets, promoting beta-cell regeneration, and influencing hepatic glucose and lipid metabolism. These actions suggest its potential as a therapeutic for metabolic dysfunctions like diabetes, obesity, and steatohepatitis. However, clinical applications of IL-22 face challenges related to off-target effects and safety concerns. This review explores IL-22's physiological roles, regulatory mechanisms, and profound influence on metabolic tissues. It also underscores IL-22's dual role in metabolic health and disease, advocating further research to harness its therapeutic potential.

The role of IL-22 in cancer

Interleukin-22, discovered in the year of 2000, is a pleiotropic Th17 cytokine from the IL-10 family of cytokines. IL-22 signals through the type 2 cytokine receptor complex IL-22R and predominantly activates STAT3. This pathway leads to the transcription of several different types of genes, giving IL-22 context-specific functions ranging from inducing antimicrobial peptide expression to target cell proliferation. In recent years, it has been shown that IL-22 is involved in the pathogenesis of neoplasia in some cancers through its pro-proliferative and anti-apoptotic effects. This review highlights studies with recent discoveries and conclusions drawn on IL-22 and its involvement and function in various cancers. Such a study may be helpful to better understand the role of IL-22 in cancer so that new treatment could be developed targeting IL-22.

IL-22 in Atopic Dermatitis

Atopic dermatitis (AD) is a prevalent and chronic inflammatory skin condition characterized by a multifaceted pathophysiology that gives rise to diverse clinical manifestations. The management of AD remains challenging due to the suboptimal efficacy of existing treatment options. Nonetheless, recent progress in elucidating the underlying mechanisms of the disease has facilitated the identification of new potential therapeutic targets and promising drug candidates. In this review, we summarize the newest data, considering multiple connections between IL-22 and AD. The presence of circulating IL-22 has been found to correlate with the severity of AD and is identified as a critical factor driving the inflammatory response associated with the condition. Elevated levels of IL-22 in patients with AD are correlated with increased proliferation of keratinocytes, alterations in the skin microbiota, and impaired epidermal barrier function. Collectively, these factors contribute to the manifestation of the characteristic symptoms observed in AD.

A comprehensive immunobiology review of IBD: With a specific glance to Th22 lymphocytes development, biology, function, and role in IBD

The two primary forms of inflammatory disorders of the small intestine andcolon that make up inflammatory bowel disease (IBD) are ulcerative colitis (UC) and Crohn's disease (CD). While ulcerative colitis primarily affects the colon and the rectum, CD affects the small and large intestines, as well as the esophagus,mouth, anus, andstomach. Although the etiology of IBD is not completely clear, and there are many unknowns about it, the development, progression, and recurrence of IBD are significantly influenced by the activity of immune system cells, particularly lymphocytes, given that the disease is primarily caused by the immune system stimulation and activation against gastrointestinal (GI) tract components due to the inflammation caused by environmental factors such as viral or bacterial infections, etc. in genetically predisposed individuals. Maintaining homeostasis and the integrity of the mucosal barrier are critical in stopping the development of IBD. Specific immune system cells and the quantity of secretory mucus and microbiome are vital in maintaining this stability. Th22 cells are helper T lymphocyte subtypes that are particularly important for maintaining the integrity and equilibrium of the mucosal barrier. This review discusses the most recent research on these cells' biology, function, and evolution and their involvement in IBD.

Multi-ancestry Genome-Wide Association Meta-Analysis Identifies Novel Loci in Atopic Dermatitis

Atopic dermatitis (AD) is a highly heritable and common inflammatory skin condition affecting children and adults worldwide. Multi-ancestry approaches to AD genetic association studies are poised to boost power to detect genetic signal and identify ancestry-specific loci contributing to AD risk. Here, we present a multi-ancestry GWAS meta-analysis of twelve AD cohorts from five ancestral populations totaling 56,146 cases and 602,280 controls. We report 101 genomic loci associated with AD, including 15 loci that have not been previously associated with AD or eczema. Fine-mapping, QTL colocalization, and cell-type enrichment analyses identified genes and cell types implicated in AD pathophysiology. Functional analyses in keratinocytes provide evidence for genes that could play a role in AD through epidermal barrier function. Our study provides new insights into the etiology of AD by harnessing multiple genetic and functional approaches to unveil the mechanisms by which AD-associated variants impact genes and cell types.

Expression and diagnostic value of interleukin-22 in rheumatoid arthritis-associated interstitial lung disease

Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is characterized by a high incidence and mortality rate, highlighting the need for biomarkers to detect ILD early in RA patients. Previous studies have shown the protective effects of Interleukin-22 (IL-22) in pulmonary fibrosis using mouse models. This study aims to assess IL-22 expression in RA-ILD to validate foundational experiments and explore its diagnostic value. The study included 66 newly diagnosed RA patients (33 with ILD, 33 without ILD) and 14 healthy controls (HC). ELISA was utilized to measure IL-22 levels and perform intergroup comparisons. The correlation between IL-22 levels and the severity of RA-ILD was examined. Logistic regression analysis was employed to screen potential predictive factors for RA-ILD risk and establish a predictive nomogram. The diagnostic value of IL-22 in RA-ILD was assessed using ROC. Subsequently, the data were subjected to 30-fold cross-validation. IL-22 levels in the RA-ILD group were lower than in the RA-No-ILD group and were inversely correlated with the severity of RA-ILD. Logistic regression analysis identified IL-22, age, smoking history, anti-mutated citrullinated vimentin antibody (MCV-Ab), and mean corpuscular hemoglobin concentration (MCHC) as independent factors for distinguishing between the groups. The diagnostic value of IL-22 in RA-ILD was moderate (AUC = 0.75) and improved when combined with age, smoking history, MCV-Ab and MCHC (AUC = 0.97). After 30-fold cross-validation, the average AUC was 0.886. IL-22 expression is dysregulated in the pathogenesis of RA-ILD. This study highlights the potential of IL-22, along with other factors, as a valuable biomarker for assessing RA-ILD occurrence and progression.

The roles of Th cells in myocardial infarction

Myocardial infarction, commonly known as a heart attack, is a serious condition caused by the abrupt stoppage of blood flow to a part of the heart, leading to tissue damage. A significant aspect of this condition is reperfusion injury, which occurs when blood flow is restored but exacerbates the damage. This review first addresses the role of the innate immune system, including neutrophils and macrophages, in the cascade of events leading to myocardial infarction and reperfusion injury. It then shifts focus to the critical involvement of CD4+ T helper cells in these processes. These cells, pivotal in regulating the immune response and tissue recovery, include various subpopulations such as Th1, Th2, Th9, Th17, and Th22, each playing a unique role in the pathophysiology of myocardial infarction and reperfusion injury. These subpopulations contribute to the injury process through diverse mechanisms, with cytokines such as IFN-γ and IL-4 influencing the balance between tissue repair and injury exacerbation. Understanding the interplay between the innate immune system and CD4+ T helper cells, along with their cytokines, is crucial for developing targeted therapies to mitigate myocardial infarction and reperfusion injury, ultimately improving outcomes for cardiac patients.

Skin, gut, and lung barrier: Physiological interface and target of intervention for preventing and treating allergic diseases

The epithelial barriers of the skin, gut, and respiratory tract are critical interfaces between the environment and the host, and they orchestrate both homeostatic and pathogenic immune responses. The mechanisms underlying epithelial barrier dysfunction in allergic and inflammatory conditions, such as atopic dermatitis, food allergy, eosinophilic oesophagitis, allergic rhinitis, chronic rhinosinusitis, and asthma, are complex and influenced by the exposome, microbiome, individual genetics, and epigenetics. Here, we review the role of the epithelial barriers of the skin, digestive tract, and airways in maintaining homeostasis, how they influence the occurrence and progression of allergic and inflammatory conditions, how current treatments target the epithelium to improve symptoms of these disorders, and what the unmet needs are in the identification and treatment of epithelial disorders.

Natural Product-Derived Compounds Targeting Keratinocytes and Molecular Pathways in Psoriasis Therapeutics

Psoriasis is a chronic autoimmune inflammatory skin disorder that affects approximately 2-3% of the global population due to significant genetic predisposition. It is characterized by an uncontrolled growth and differentiation of keratinocytes, leading to the formation of scaly erythematous plaques. Psoriasis extends beyond dermatological manifestations to impact joints and nails and is often associated with systemic disorders. Although traditional treatments provide relief, their use is limited by potential side effects and the chronic nature of the disease. This review aims to discuss the therapeutic potential of keratinocyte-targeting natural products in psoriasis and highlight their efficacy and safety in comparison with conventional treatments. This review comprehensively examines psoriasis pathogenesis within keratinocytes and the various related signaling pathways (such as JAK-STAT and NF-κB) and cytokines. It presents molecular targets such as high-mobility group box-1 (HMGB1), dual-specificity phosphatase-1 (DUSP1), and the aryl hydrocarbon receptor (AhR) for treating psoriasis. It evaluates the ability of natural compounds such as luteolin, piperine, and glycyrrhizin to modulate psoriasis-related pathways. Finally, it offers insights into alternative and sustainable treatment options with fewer side effects.

WTAP mediated m6A-modified circ_0056856 contributes to the proliferation, migration, and invasion of IL-22-stimulated human keratinocyte by miR-197-3p/CDK1 axis

BACKGROUND

Psoriasis is a chronic inflammation-associated skin disorder, and interleukin-22 (IL-22) is involved in psoriasis pathogenesis by boosting the proliferation and migration of keratinocytes. Mounting evidence has shown that circRNAs might play an important role in several aspects of psoriasis. This study is designed to explore the role and mechanism of circ_0056856 in regulating the phenotypes of IL-22-induced keratinocytes (HaCaT cells).

METHODS

Circ_0056856, microRNA-197-3p (miR-197-3p), Cyclin-dependent kinase 1 (CDK1), and Wilms tumor 1-associated protein (WTAP) levels were detected using real-time quantitative polymerase chain reaction (RT-qPCR). Cell viability, proliferation, migration, and invasion were analyzed using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), Wound scratch, and Transwell assays. After being predicted by Circinteractome or TargetScan, binding between miR-197-3p and circ_0056856 or CDK1 was verified by a dual-luciferase reporter assay. CDK1 and WTAP protein levels were determined using Western blot. Interaction between WTAP and circ_0056856 was assessed using methylated RNA immunoprecipitation (MeRIP) assay.

RESULTS

Increased circ_0056856, CDK1, and WTAP were observed in psoriasis patients and IL-22-treated HaCaT cells. Moreover, circ_0056856 knockdown might repress IL-22-induced HaCaT cell proliferation, migration, and invasion in vitro. In mechanism, circ_0056856 might function as a sponge of miR-197-3p to modulate CDK1 expression, and WTAP improved circ_0056856 expression via m6A methylation.

CONCLUSION

WTAP-guided m6A modified circ_0056856 facilitates IL-22-stimulated HaCaT cell damage through the miR-197-3p/CDK1 axis, which could provide novel insights into psoriasis treatment.

Dupilumab-associated head and neck dermatitis shows a pronounced type 22 immune signature mediated by oligoclonally expanded T cells

Dupilumab, an IL4R-blocking antibody, has shown clinical efficacy for atopic dermatitis (AD) treatment. In addition to conjunctivitis/blepharitis, the de novo appearance of head/neck dermatitis is now recognized as a distinct side effect, occurring in up to 10% of patients. Histopathological features distinct from AD suggest a drug effect, but exact underlying mechanisms remain unknown. We profiled punch biopsies from dupilumab-associated head and neck dermatitis (DAHND) by using single-cell RNA sequencing and compared data with untreated AD and healthy control skin. We show that dupilumab treatment was accompanied by normalization of IL-4/IL-13 downstream activity markers such as CCL13, CCL17, CCL18 and CCL26. By contrast, we found strong increases in type 22-associated markers (IL22, AHR) especially in oligoclonally expanded T cells, accompanied by enhanced keratinocyte activation and IL-22 receptor upregulation. Taken together, we demonstrate that dupilumab effectively dampens conventional type 2 inflammation in DAHND lesions, with concomitant hyperactivation of IL22-associated responses.

T cell-mediated skin-brain axis: Bridging the gap between psoriasis and psychiatric comorbidities

Psoriasis, a chronic inflammatory skin condition, is often accompanied by psychiatric comorbidities such as anxiety, depression, suicidal ideation, and other mental disorders. Psychological disorders may also play a role in the development and progression of psoriasis. The intricate interplay between the skin diseases and the psychiatric comorbidities is mediated by the 'skin-brain axis'. Understanding the mechanisms underlying psoriasis and psychiatric comorbidities can help improve the efficacy of treatment by breaking the vicious cycle of diseases. T cells and related cytokines play a key role in the pathogenesis of psoriasis and psychiatric diseases, and are crucial components of the 'skin-brain axis'. Apart from damaging the blood-brain barrier (BBB) directly, T cells and secreted cytokines could interact with the hypothalamic-pituitary-adrenal axis (HPA axis) and the sympathetic nervous system (SNS) to exacerbate skin diseases or mental disorders. However, few reviews have systematically summarized the roles and mechanisms of T cells in the interaction between psoriasis and psychiatric comorbidities. In this review, we discussed several key T cells and their roles in the 'skin-brain axis', with a focus on the mechanisms underlying the interplay between psoriasis and mental commodities, to provide data that might help develop effective strategies for the treatment of both psoriasis and psychiatric comorbidities.

The relationship between umbilical cord blood IL-22 level and infantile eczema at 42 days

Background

The occurrence of eczema is related to helper T 22 (Th22) cytokine disorder, and Th22 mainly secretes interleukin-22 (IL-22). This study aims to investigate the predictive value of umbilical cord blood IL-22 levels on the onset of eczema in infants within 42 days.

Study design

The study selected 157 full-term healthy neonates born between September 2020 and May 2021. Cord blood was collected immediately after birth to determine IL-22 levels, and the infants were followed up for 42 days to assess the incidence of eczema.

Results

Among the 157 infants who completed the 42-day follow-up, 86 developed eczema and 71 did not. The level of IL-22 in the umbilical cord blood of the eczema group was lower than that of the non-eczema group (p < 0.05). Additionally, the incidence of eczema in children whose Family history of allergy was significantly higher than in the group without eczema (p < 0.05). Logistic regression analysis indicated that low cord blood IL-22 levels and a family history of allergies were independent risk factors for eczema (p < 0.05). The ROC curve of cord blood IL-22 levels and infant eczema showed that the cut-off value is 36.362 pg/ml, the area under the curve (AUC) is 0.613, the standard error is 0.045, the 95% CI is 0.526-0.701, the sensitivity is 63.4%, and the specificity is 57.0%. Therefore, there is a certain correlation between cord blood IL-22 levels and the incidence of infant eczema.

Conclusions

Low IL-22 levels in umbilical cord blood may be linked to the development of infant eczema within 42 days, indicating a potential predictive value, although this value appears to be limited.

Understanding Type 3 Innate Lymphoid Cells and Crosstalk with the Microbiota: A Skin Connection

Innate lymphoid cells (ILCs) are a diverse population of lymphocytes classified into natural killer (NK) cells, ILC1s, ILC2s, ILC3s, and ILCregs, broadly following the cytokine secretion and transcription factor profiles of classical T cell subsets. Nonetheless, the ILC lineage does not have rearranged antigen-specific receptors and possesses distinct characteristics. ILCs are found in barrier tissues such as the skin, lungs, and intestines, where they play a role between acquired immune cells and myeloid cells. Within the skin, ILCs are activated by the microbiota and, in turn, may influence the microbiome composition and modulate immune function through cytokine secretion or direct cellular interactions. In particular, ILC3s provide epithelial protection against extracellular bacteria. However, the mechanism by which these cells modulate skin health and homeostasis in response to microbiome changes is unclear. To better understand how ILC3s function against microbiota perturbations in the skin, we propose a role for these cells in response to Cutibacterium acnes, a predominant commensal bacterium linked to the inflammatory skin condition, acne vulgaris. In this article, we review current evidence describing the role of ILC3s in the skin and suggest functional roles by drawing parallels with ILC3s from other organs. We emphasize the limited understanding and knowledge gaps of ILC3s in the skin and discuss the potential impact of ILC3-microbiota crosstalk in select skin diseases. Exploring the dialogue between the microbiota and ILC3s may lead to novel strategies to ameliorate skin immunity.

Enhancement of recombinant human interleukin-22 production by fusing with human serum albumin and supplementing N-acetylcysteine in Pichia Pastoris

Interleukin-22 (IL-22) plays an important role in the treatment of organ failure, which can induce anti-apoptotic and proliferative signaling pathways; Nevertheless, the practical utilization of IL-22 is hindered by the restricted efficacy of its production. Pichia pastoris presents a viable platform for both industrial and pharmaceutical applications. In this study, we successfully generated a fusion protein consisting of truncated human serum albumin and human IL-22 (HSA-hIL-22) using P. pastoris, and examined the impact of antioxidants on HSA-hIL-22 production. We have achieved the production of HSA-hIL-22 in the culture medium at a yield of approximately 2.25 mg/ml. Moreover, 0-40 mM ascorbic acid supplementation did not significantly affect HSA-hIL-22 production or the growth rate of the recombinant strain. However, 80 mM ascorbic acid treatment had a detrimental effect on the expression of HSA-hIL-22. In addition, 5-10 mM N-acetyl-l-cysteine (NAC) resulted in an increase of HSA-hIL-22 production, accompanied by a reduction in the growth rate of the recombinant strain. Conversely, 20-80 mM NAC supplementation inhibited the growth of the recombinant strains and reduced intact HSA-hIL-22 production. However, neither NAC nor ascorbic acid exhibited any effect on superoxide dismutase (SOD) and malondialdehyde (MDA) levels, except that NAC increased GSH content. Furthermore, our findings indicate that recombinant HSA-hIL-22, which demonstrated the ability to stimulate the proliferation of HepG2 cells, possesses bioactivity. In addition, NAC did not affect HSA-hIL-22 bioactivity. In conclusion, our study demonstrates that NAC supplementation can enhance the secretion of functional HSA-hIL-22 proteins produced in P. pastoris without compromising their activity.

Therapeutic effectiveness of upadacitinib on individual types of rash in Japanese patients with moderate-to-severe atopic dermatitis

Atopic dermatitis (AD) is a chronic eczematous disease with various types of rash, erythema, edema/papulation, excoriation, or lichenification. Janus kinase 1 inhibitor upadacitinib is effective for moderate-to-severe AD. We aimed to investigate the therapeutic effects of upadacitinib on each rash type in AD patients in real-world clinical practice. Seventy-two Japanese patients with moderate-to-severe AD were treated with oral upadacitinib 15 mg/day plus topical corticosteroids. The Eczema Area and Severity Index (EASI) scores for erythema, edema/papulation, excoriation, or lichenification on the whole body or on head and neck, upper limbs, lower limbs, or trunk were assessed at weeks 0, 4, and 12 of treatment. The proportions of patients who achieved resolution or at least 75% reduction of EASI from baseline (EASI 75) for individual rash types were calculated at weeks 4 and 12 on the whole body or each anatomical site. The resolution rates for excoriation, erythema, edema/papulation, or lichenification on the whole body were 38.3%, 23.7%, 21.7%, and 8.3% at week 4 and 18.3%, 18.6%, 11.6%, and 13.3% at week 12, respectively. The EASI scores for all rash types significantly decreased at weeks 4 and 12 compared to week 0. The achievement rates of EASI 75 for excoriation, erythema, edema/papulation, or lichenification on the whole body were 67.2%, 66.7%, 49.2%, and 37.7% at week 4 and 57.3%, 65%, 41%, and 41% at week 12, respectively. The achievement rate of EASI 75 for erythema on head and neck at week 4 (45.3%) was lower than that on upper limbs (71%) and on lower limbs (70.8%), and that on head and neck at week 12 (42.2%) was lower than that on lower limbs (69.2%). These results indicate that upadacitinib is effective for all AD rash types, especially for excoriation and erythema, while head-and-neck erythema might be less responsive to upadacitinib.

IL-20 Cytokines Are Involved in the Repair of Airway Epithelial Barrier: Implication in Exposure to Cigarette Smoke and in COPD Pathology

BACKGROUND

Dysregulated inflammation as seen in chronic obstructive pulmonary disease (COPD) is associated with impaired wound healing. IL-20 cytokines are known to be involved in wound healing processes. The purpose of this study was to use ex vivo and in vitro approaches mimicking COPD to evaluate the potential modulatory role of interleukin-20 (IL-20) on the inflammatory and healing responses to epithelial wounding.

METHODS

The expression of IL-20 cytokines and their receptors was investigated in lung-derived samples collected from non-COPD and COPD patients, from mice chronically exposed to cigarette smoke and from airway epithelial cells from humans and mice exposed in vitro to cigarette smoke. To investigate the role of IL-20 cytokines in wound healing, experiments were performed using a blocking anti-IL-20Rb antibody.

RESULTS

Of interest, IL-20 cytokines and their receptors were expressed in bronchial mucosa, especially on airway epithelial cells. Their expression correlated with the disease severity. Blocking these cytokines in a COPD context improved the repair processes after a lesion induced by scratching the epithelial layer.

CONCLUSIONS

Collectively, this study highlights the implication of IL-20 cytokines in the repair of the airway epithelium and in the pathology of COPD. IL-20 subfamily cytokines might provide therapeutic benefit for patients with COPD to improve epithelial healing.

Clinical trials of antibody drugs in the treatments of atopic dermatitis

Atopic dermatitis (AD) is one of the most common, relapsing, chronic inflammatory skin disease, being regarded as a global health issue. Recent studies have shown that Th2 cell-mediated type 2 immunity plays a central role in AD. The type 2 inflammatory cytokines such as IL-4, IL-13, IL-22, IL-31, IL-17 and IL-5 mediate the pathogenesis of AD. A variety of antibody drugs targeting these cytokines have been developed to treat AD in clinics. Notably, several antibody drugs have exhibited high efficacy in treating atopic dermatitis in previous studies, demonstrating that they could be therapeutic methods for AD patients. Herein, we reviewed the clinical trials of antibody drugs in the treatment of AD, which provides a useful guideline for clinicians to treat patients with AD in clinics.

Endogenous interleukin-22 prevents cardiac rupture after myocardial infarction in mice

Myocardial infarction (MI) can result in fatal myocardial rupture or heart failure due to adverse remodeling and dysfunction of the left ventricle. Although recent studies have shown that exogenous interleukin (IL)-22 shows cardioprotective effect after MI, the pathophysiological significance of endogenous IL-22 is unknown. In this study, we investigated the role of endogenous IL-22 in a mouse model of MI. We produced MI model by permanent ligation of the left coronary artery in wild-type (WT) and IL-22 knock-out (KO) mice. The post-MI survival rate was significantly worse in IL-22KO mice than in WT mice due to a higher rate of cardiac rupture. Although IL-22KO mice exhibited a significantly greater infarct size than WT mice, there was no significant difference in left ventricular geometry or function between WT and IL-22KO mice. IL-22KO mice showed increase in infiltrating macrophages and myofibroblasts, and altered expression pattern of inflammation- and extracellular matrix (ECM)-related genes after MI. While IL-22KO mice showed no obvious changes in cardiac morphology or function before MI, expressions of matrix metalloproteinase (MMP)-2 and MMP-9 were increased, whereas that of tissue inhibitor of MMPs (TIMP)-3 was decreased in cardiac tissue. Protein expression of IL-22 receptor complex, IL-22 receptor alpha 1 (IL-22R1) and IL-10 receptor beta (IL-10RB), were increased in cardiac tissue 3 days after MI, regardless of the genotype. We propose that endogenous IL-22 plays an important role in preventing cardiac rupture after MI, possibly by regulating inflammation and ECM metabolism.