The ST2/IL-33 Axis in Immune Cells during Inflammatory Diseases

Pharmacogenetics of therapies in rheumatoid arthritis: An update

Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory arthritis. Despite many treatment advances, achieving remission or low-disease activity in RA remains challenging, often requiring trial and error approaches with numerous medications. Precision medicine, particularly pharmacogenomics, explores how genetic factors influence drug response in individual patients, and incorporates such factors to develop personalized treatments for individual patients. Genetic variations in drug-metabolizing enzymes, transporters, and targets may contribute to inter-individual differences in drug efficacy and toxicity. Advancements in molecular sequencing have allowed rapid identification of such variants, including single nucleotide polymorphisms (SNPs). This review highlights recent major findings in the pharmacogenetics of therapies in RA, focusing on key genes and SNPs to provide insights into current trends and developments in this field.

Difamilast, a Topical Phosphodiesterase 4 Inhibitor, Produces Soluble ST2 via the AHR-NRF2 Axis in Human Keratinocytes

Difamilast, a phosphodiesterase 4 (PDE4) inhibitor, has been shown to be effective in the treatment of atopic dermatitis (AD), although the mechanism involved remains unclear. Since IL-33 plays an important role in the pathogenesis of AD, we investigated the effect of difamilast on IL-33 activity. Since an in vitro model of cultured normal human epidermal keratinocytes (NHEKs) has been utilized to evaluate the pharmacological potential of adjunctive treatment of AD, we treated NHEKs with difamilast and analyzed the expression of the suppression of tumorigenicity 2 protein (ST2), an IL-33 receptor with transmembrane (ST2L) and soluble (sST2) isoforms. Difamilast treatment increased mRNA and protein levels of sST2, a decoy receptor suppressing IL-33 signal transduction, without affecting ST2L expression. Furthermore, supernatants from difamilast-treated NHEKs inhibited IL-33-induced upregulation of TNF-α, IL-5, and IL-13 in KU812 cells, a basophil cell line sensitive to IL-33. We also found that difamilast activated the aryl hydrocarbon receptor (AHR)-nuclear factor erythroid 2-related factor 2 (NRF2) axis. Additionally, the knockdown of AHR or NRF2 abolished the difamilast-induced sST2 production. These results indicate that difamilast treatment produces sST2 via the AHR-NRF2 axis, contributing to improving AD symptoms by inhibiting IL-33 activity.

CXCL3: A key player in tumor microenvironment and inflammatory diseases

CXCL3 (C-X-C Motif Chemokine 3), a member of the C-X-C chemokine subfamily, operates as a potent chemoattractant for neutrophils, thereby orchestrating the recruitment and migration of leukocytes alongside eliciting an inflammatory response. Recent inquiries have shed light on the pivotal roles of CXCL3 in the context of carcinogenesis. In the tumor microenvironment, CXCL3 emanating from both tumor and stromal cells intricately modulates cellular behaviors through autocrine and paracrine actions, primarily via interaction with its receptor CXCR2. Activation of signaling cascades such as ERK/MAPK, AKT, and JAK2/STAT3 underscores CXCL3's propensity to favor tumorigenic processes. However, CXCL3 exhibits dualistic behaviors, as evidenced by its capacity to exert anti-tumor effects under specific conditions. Additionally, the involvement of CXCL3 extends to inflammatory disorders like eclampsia, obesity, and asthma. This review encapsulates the structural attributes, biological functionalities, and molecular underpinnings of CXCL3 across both tumorigenesis and inflammatory diseases.

ST2 and IL-33 polymorphisms and the development of childhood asthma: a prospective birth cohort study in Finnish children

The ST2/IL-33 signaling pathway has an important role in the host inflammatory response. Here we aimed to study the association of ST2 and IL-33 polymorphisms with serum soluble (s) ST2 and IL-33 concentrations in healthy Finnish children and, in addition, their association with childhood asthma. In total, 146 children were followed from birth to the age 7 years for the development of asthma. Single-nucleotide polymorphisms (SNPs) in ST2 and IL-33 were determined, and associations of the SNP variants with serum levels of sST2 and IL-33 at age of 13 months and with recurrent wheezing and childhood asthma at 7 years of age were analyzed. Children with ST2 rs1041973 AC/AA genotypes had significantly lower level of serum sST2 (2453 pg/mL; IQR 2265) than those with CC genotype (5437 pg/mL; IQR 2575; p = < 0.0001). Similar difference was also observed with ST2 rs13408661. No differences were observed between subjects with studied IL-33 SNPs. Children who carried genetic variants of ST2 rs1041973 or rs13408661 seemed to have a higher risk of asthma. In contrast, children who carried genetic variants of IL-33 rs12551268 were less often diagnosed with asthma. Even though these SNPs seemed to associate with asthma, the differences were not statistically significant.

Circulating Markers of Necroptosis in Acute Pancreatitis

OBJECTIVES

Necroptosis, a programmed inflammatory cell death, is involved in the pathogenesis of acute pancreatitis (AP). We compared levels of interleukin (IL)-33 (released upon necroptosis), sST2 (soluble IL-33 receptor), MLKL, RIPK1 and RIPK3 (necroptosis executioner proteins), and proinflammatory cytokines IL-6, TNF and IL-1β at various severity categories and stages of AP.

METHODS

Plasma from 20 patients with early mild AP (MAP) (symptom onset < 72 h), 7 with severe AP (SAP) without and 4 with persistent organ failure (OF) at sampling, 8 patients with late SAP and 20 healthy controls (HC) were studied by ELISAs.

RESULTS

Early sST2 and IL-6 levels predicted the development of SAP and were higher in both MAP and early and late SAP than in HC. RIPK3 levels were higher than in HC in the patients who had or would later have SAP. MLKL levels were associated with the presence of OFs, particularly in the late phase, but were also higher in MAP than in HC.

CONCLUSIONS

sST2, RIPK3 and IL-6 levels may have prognostic value in AP. Elevated MLKL levels are associated with OF in AP. Better understanding of necroptosis in AP pathophysiology is needed to evaluate whether inhibiting and targeting necroptosis is a potential therapeutic option in AP.

Amphiregulin, ST2, and REG3α biomarker risk algorithms as predictors of nonrelapse mortality in patients with acute GVHD

ABSTRACT

Graft-versus-host disease (GVHD) is a major cause of nonrelapse mortality (NRM) after allogeneic hematopoietic cell transplantation. Algorithms containing either the gastrointestinal (GI) GVHD biomarker amphiregulin (AREG) or a combination of 2 GI GVHD biomarkers (suppressor of tumorigenicity-2 [ST2] + regenerating family member 3 alpha [REG3α]) when measured at GVHD diagnosis are validated predictors of NRM risk but have never been assessed in the same patients using identical statistical methods. We measured the serum concentrations of ST2, REG3α, and AREG by enzyme-linked immunosorbent assay at the time of GVHD diagnosis in 715 patients divided by the date of transplantation into training (2004-2015) and validation (2015-2017) cohorts. The training cohort (n = 341) was used to develop algorithms for predicting the probability of 12-month NRM that contained all possible combinations of 1 to 3 biomarkers and a threshold corresponding to the concordance probability was used to stratify patients for the risk of NRM. Algorithms were compared with each other based on several metrics, including the area under the receiver operating characteristics curve, proportion of patients correctly classified, sensitivity, and specificity using only the validation cohort (n = 374). All algorithms were strong discriminators of 12-month NRM, whether or not patients were systemically treated (n = 321). An algorithm containing only ST2 + REG3α had the highest area under the receiver operating characteristics curve (0.757), correctly classified the most patients (75%), and more accurately risk-stratified those who developed Minnesota standard-risk GVHD and for patients who received posttransplant cyclophosphamide-based prophylaxis. An algorithm containing only AREG more accurately risk-stratified patients with Minnesota high-risk GVHD. Combining ST2, REG3α, and AREG into a single algorithm did not improve performance.

HucMSC-Ex alleviates DSS-induced colitis in mice by decreasing mast cell activation via the IL-33/ST2 axis

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory disease that poses challenges in terms of treatment. The precise mechanism underlying the role of human umbilical cord mesenchymal stem cell-derived exosome (HucMSC-Ex) in the inflammatory repair process of IBD remains elusive. Mucosal mast cells accumulate within the intestinal tract and exert regulatory functions in IBD, thus presenting a novel target for addressing this intestinal disease.

METHODS

A mouse model of Dextran Sulfate Sodium (DSS)-induced colitis was established and hucMSC-Ex were administered to investigate their impact on the regulation of intestinal mast cells. An in vitro co-culture model using the human clonal colorectal adenocarcinoma cell line (Caco-2) and human mast cell line (LAD2) was also established for further exploration of the effect of hucMSC-Ex.

RESULTS

We observed the accumulation of mast cells in the intestines of patients with IBD as well as mice. In colitis mice, there was an upregulation of mast cell-related tryptase, interleukin-33 (IL-33), and suppression of tumorigenicity 2 receptor (ST2 or IL1RL1), and the function of the intestinal mucosal barrier related to intestinal tight junction protein was weakened. HucMSC-Ex treatment significantly reduced mast cell infiltration and intestinal damage. In the co-culture model, a substantial number of mast cells interact with the epithelial barrier, triggering activation of the IL-33/IL1RL1 (ST2) pathway and subsequent release of inflammatory factors and trypsin. This disruption leads to aberrant expression of tight junction proteins, which can be alleviated by supplementation with hucMSC-Ex.

CONCLUSION

Our results suggest that hucMSC-Ex may reduce the release of mast cell mediators via the IL-33/IL1RL1 (ST2) axis, thereby mitigating its detrimental effects on intestinal barrier function.

Mast cells control lung type 2 inflammation via prostaglandin E2-driven soluble ST2

Severe asthma and sinus disease are consequences of type 2 inflammation (T2I), mediated by interleukin (IL)-33 signaling through its membrane-bound receptor, ST2. Soluble (s)ST2 reduces available IL-33 and limits T2I, but little is known about its regulation. We demonstrate that prostaglandin E2 (PGE2) drives production of sST2 to limit features of lung T2I. PGE2-deficient mice display diminished sST2. In humans with severe respiratory T2I, urinary PGE2 metabolites correlate with serum sST2. In mice, PGE2 enhanced sST2 secretion by mast cells (MCs). Mice lacking MCs, ST2 expression by MCs, or E prostanoid (EP)2 receptors by MCs showed reduced sST2 lung concentrations and strong T2I. Recombinant sST2 reduced T2I in mice lacking PGE2 or ST2 expression by MCs back to control levels. PGE2 deficiency also reversed the hyperinflammatory phenotype in mice lacking ST2 expression by MCs. PGE2 thus suppresses T2I through MC-derived sST2, explaining the severe T2I observed in low PGE2 states.

Newborn Screening for High-Risk Congenital Heart Disease by Dried Blood Spot Biomarker Analysis

Importance

Congenital heart disease (CHD) is the most common human organ malformation, affecting approximately 1 of 125 newborns globally.

Objectives

Assessing the performance of 2 diagnostic tests using minimal amounts of dried blood spots (DBS) to identify high-risk CHD compared with controls in a Swedish cohort of neonates.

Design, Setting, and Participants

This diagnostic study took place in Sweden between 2019 and 2023 and enrolled full-term babies born between 2005 and 2023. All cases were identified through centralized pediatric cardiothoracic surgical services in Lund and Gothenburg, Sweden. Controls were followed up for 1 year to ensure no late presentations of high-risk CHD occurred. Cases were verified through surgical records and echocardiography.

Exposure

High-risk CHD, defined as cases requiring cardiac surgical management during infancy due to evolving signs of heart failure or types in which the postnatal circulation depends on patency of the arterial duct. Using 3-μL DBS samples, automated quantitative tests for NT-proBNP and interleukin 1 receptor-like 1 (IL-1 RL1; formerly known as soluble ST2) were compared against established CHD screening methods.

Main Outcomes and Measures

Performance of DBS tests to detect high-risk CHD using receiver operating characteristic curves; Bland-Altman and Pearson correlation analyses to compare IL-1 RL1 DBS with plasma blood levels.

Results

A total of 313 newborns were included (mean [SD] gestational age, 39.4 [1.3] weeks; 181 [57.8%] male). Mean (SD) birthweight was 3495 (483) grams. Analyzed DBS samples included 217 CHD cases and 96 controls. Among the CHD cases, 188 participants (89.3%) were high-risk types, of which 73 (38.8%) were suspected prenatally. Of the 188 high-risk cases, 94 (50.0%) passed pulse oximetry screening and 36 (19.1%) were initially discharged after birth without diagnoses. Combining NT-proBNP and IL-1 RL1 tests performed well in comparison with existing screening methods and enabled additional identification of asymptomatic babies with receiver operating characteristic area under the curve 0.95 (95% CI, 0.93-0.98).

Conclusions and relevance

In this diagnostic study, NT-proBNP and IL-1 RL1 DBS assays identified high-risk CHD in a timely manner, including in asymptomatic newborns, and improved overall screening performance in this cohort from Sweden. Prospective evaluation of this novel approach is warranted.

Leishmania exploits host cAMP/EPAC/calcineurin signaling to induce an IL-33-mediated anti-inflammatory environment for the establishment of infection

Host anti-inflammatory responses are critical for the progression of visceral leishmaniasis, and the pleiotropic cytokine interleukin (IL)-33 was found to be upregulated in infection. Here, we documented that IL-33 induction is a consequence of elevated cAMP-mediated exchange protein activated by cAMP (EPAC)/calcineurin-dependent signaling and essential for the sustenance of infection. Leishmania donovani-infected macrophages showed upregulation of IL-33 and its neutralization resulted in decreased parasite survival and increased inflammatory responses. Infection-induced cAMP was involved in IL-33 production and of its downstream effectors PKA and EPAC, only the latter was responsible for elevated IL-33 level. EPAC initiated Rap-dependent phospholipase C activation, which triggered the release of intracellular calcium followed by calcium/calmodulin complex formation. Screening of calmodulin-dependent enzymes affirmed involvement of the phosphatase calcineurin in cAMP/EPAC/calcium/calmodulin signaling-induced IL-33 production and parasite survival. Activated calcineurin ensured nuclear localization of the transcription factors, nuclear factor of activated T cell 1 and hypoxia-inducible factor 1 alpha required for IL-33 transcription, and we further confirmed this by chromatin immunoprecipitation assay. Administering specific inhibitors of nuclear factor of activated T cell 1 and hypoxia-inducible factor 1 alpha in BALB/c mouse model of visceral leishmaniasis decreased liver and spleen parasite burden along with reduction in IL-33 level. Splenocyte supernatants of inhibitor-treated infected mice further documented an increase in tumor necrosis factor alpha and IL-12 level with simultaneous decrease of IL-10, thereby indicating an overall disease-escalating effect of IL-33. Thus, this study demonstrates that cAMP/EPAC/calcineurin signaling is crucial for the activation of IL-33 and in effect creates anti-inflammatory responses, essential for infection.

Inhibition of Interleukin-33 to Reduce Glomerular Endothelial Inflammation in Diabetic Kidney Disease

Introduction

Inflammation is a significant contributor to cardiorenal morbidity and mortality in diabetic kidney disease (DKD). The pathophysiological mechanisms linking systemic, subacute inflammation and local, kidney injury-initiated immune maladaptation is partially understood.

Methods

Here, we explored the expression of proinflammatory cytokines in patients with DKD; investigated mouse models of type 1 and type 2 diabetes (T2D); evaluated glomerular signaling in vitro; performed post hoc analyses of systemic and urinary markers of inflammation; and initiated a phase 2b clinical study (FRONTIER-1; NCT04170543).

Results

Transcriptomic profiling of kidney biopsies from patients with DKD revealed significant glomerular upregulation of interleukin-33 (IL-33). Inhibition of IL-33 signaling reduced glomerular damage and albuminuria in the uninephrectomized db/db mouse model (T2D/DKD). On a cellular level, inhibiting IL-33 improved glomerular endothelial health by decreasing cellular inflammation and reducing release of proinflammatory cytokines. Therefore, FRONTIER-1 was designed to test the safety and efficacy of the IL-33-targeted monoclonal antibody tozorakimab in patients with DKD. So far, 578 patients are enrolled in FRONTIER-1. The baseline inflammation status of participants (N > 146) was assessed in blood and urine. Comparison to independent reference cohorts (N > 200) validated the distribution of urinary tumor necrosis factor receptor 1 (TNFR1) and C-C motif chemokine ligand 2 (CCL2). Treatment with dapagliflozin for 6 weeks did not alter these biomarkers significantly.

Conclusion

We show that blocking the IL-33 pathway may mitigate glomerular endothelial inflammation in DKD. The findings from the FRONTIER-1 study will provide valuable insights into the therapeutic potential of IL-33 inhibition in DKD.

IL-33 Suppresses the Progression of Atherosclerosis via the ERK1/2-IRF1-VCAM-1 Pathway

PURPOSE

This study was designed to explore the effects of interleukin 33 (IL-33) on the progression of atherosclerosis and the possible mechanism.

METHODS

The adhesion assay was performed on isolated peripheral blood mononuclear cells (PBMCs) and human umbilical vein endothelial cells (HUVEC). The expression of proteins and messenger RNA (mRNA) were detected by western blot and quantitative real-time polymerase chain reaction (PCR), including intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and P-selectin. The effect of IL-33 on the interaction of growth stimulation expressed gene 2 (ST2) with myeloid differentiation factor 88 (MyD88) and interleukin-1 receptor-associated kinase (IRAK) 1/4 were investigated using co-immunoprecipitation assay. An apolipoprotein (Apo) E-/- mice model was used to confirm the effect of IL-33 on atherosclerosis progression. Area of plaques was recorded by hematoxylin-eosin (H&E) staining. The severity of atherosclerosis plaque was evaluated using immunohistochemistry assay, and lipid accumulation was measured by an oil red O staining. In contrast, western blot was performed to detect the expression levels of VCAM-1, extracellular signal-regulated kinase (ERK) 1/2, and interferon regulatory factor 1 (IRF1).

RESULTS

Our study observed that IL-33 suppressed cell adhesion and the expression of VCAM-1 in tumor necrosis factor-α (TNF-α) exposed HUVEC. Moreover, the addition of IL-33 significantly inhibited the expression of IRF1 and the binding level of IRF1 to VCAM-1 and also promoted the phosphorylation level of IRAK1/4 and ERK1/2 compared to TNF-α-stimulated HUVEC. The ST2 neutralizing antibody or ERK pathway inhibitor SCH772984 reversed the regulatory effects of IL-33 on HUVEC, suggesting that IL-33 suppressed IRF1 and VCAM-1 dependent on binding to ST2 and activating the ERK1/2 signaling pathway. Further investigation in vivo confirmed that IL-33 decreased the expressions of IRF1 and VCAM-1 by activating the phosphorylation of ERK1/2 in the thoracic aorta of Apo E-/- mice.

CONCLUSION

In conclusion, our results demonstrated that IL-33 plays a protective role in the progression of atherosclerosis by inhibiting cell adhesion via the ERK1/2-IRF1-VCAM-1 pathway. This study may provide a potential therapeutic way to prevent the development of atherosclerosis.

Coagulation and Inflammation in COVID-19: Reciprocal Relationship between Inflammatory and Coagulation Markers

The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), formerly known as 2019-nCoV. Numerous cellular and biochemical issues arise after COVID-19 infection. The severe inflammation that is caused by a number of cytokines appears to be one of the key hallmarks of COVID-19. Additionally, people with severe COVID-19 have coagulopathy and fulminant thrombotic events. We briefly reviewed the COVID-19 disease at the beginning of this paper. The inflammation and coagulation markers and their alterations in COVID-19 illness are briefly discussed in the parts that follow. Next, we talked about NETosis, which is a crucial relationship between coagulation and inflammation. In the end, we mentioned the two-way relationship between inflammation and coagulation, as well as the factors involved in it. We suggest that inflammation and coagulation are integrated systems in COVID-19 that act on each other in such a way that not only inflammation can activate coagulation but also coagulation can activate inflammation.

Statin prevents cancer development in chronic inflammation by blocking interleukin 33 expression

Chronic inflammation is a major cause of cancer worldwide. Interleukin 33 (IL-33) is a critical initiator of cancer-prone chronic inflammation; however, its induction mechanism by environmental causes of chronic inflammation is unknown. Herein, we demonstrate that Toll-like receptor (TLR)3/4-TBK1-IRF3 pathway activation links environmental insults to IL-33 induction in the skin and pancreas inflammation. An FDA-approved drug library screen identifies pitavastatin to effectively suppress IL-33 expression by blocking TBK1 membrane recruitment/activation through the mevalonate pathway inhibition. Accordingly, pitavastatin prevents chronic pancreatitis and its cancer sequela in an IL-33-dependent manner. The IRF3-IL-33 axis is highly active in chronic pancreatitis and its associated pancreatic cancer in humans. Interestingly, pitavastatin use correlates with a significantly reduced risk of chronic pancreatitis and pancreatic cancer in patients. Our findings demonstrate that blocking the TBK1-IRF3-IL-33 signaling axis suppresses cancer-prone chronic inflammation. Statins present a safe and effective prophylactic strategy to prevent chronic inflammation and its cancer sequela.

Soluble suppression of tumorigenicity 2 associated with major adverse cardiac events in children with myocarditis

Objective

Soluble suppression of tumorigenicity 2 (sST2) is associated with the prognosis of some cardiac diseases, but studies on sST2 and the prognosis of patients with myocarditis are rare. This study investigated the relationship between major adverse cardiovascular events (MACEs) and sST2 during hospitalization in pediatric patients with myocarditis.

Methods

This was a single-center retrospective cohort study. A total of 252 patients aged ≤14 years diagnosed with myocarditis were enrolled. Events during the hospitalization were defined as MACEs (all-cause death > new heart failure > ventricular arrhythmia).

Results

A total of 25 people had MACEs during their hospital stay. The mortality during hospitalization was 6/23 (26%) in patients with heart failure and 3/10 (30%) in patients with ventricular arrhythmias. After including these risk factors in a multivariate logistic regression analysis, NT-proBNP (OR 4.323; 95% CI, 2.433-7.679; p < 0.001) and sST2 (OR 1.020; 95% CI, 1.003-1.037; p = 0.022) remained statistically significant and were independent risk factors for MACEs during hospitalization in pediatric myocarditis patients.

Conclusions

Elevated levels of NT-proBNP and sST2 were independently associated with major adverse cardiovascular events during hospitalization in children with myocarditis, and both showed good predictive efficacy.

The intriguing role of IL33/ST2 axis signaling in oral diseases - A systematic review

PURPOSE

Oral diseases act as a silent epidemic, and the pathogenetic role of interleukin-33/suppression of tumorigenicity-2 axis (IL-33/ST2) remains unclear due to a lack of literature. This review has attempted to highlight the importance of this axis in oral diseases, which may be helpful in developing therapeutic modalities required to halt disease progression.

MATERIALS AND METHODS

A thorough search was conducted using various databases. Original research articles that assessed both IL-33 and ST2 levels in oral diseases using different techniques were included in the review. The risk of bias for each study was analyzed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool and Review Manager 5.4 was used to output the results.

RESULTS

In the qualitative data synthesis we included 13 published articles. The most commonly used method was serum estimation, while methods with optimistic results were saliva, real-time quantitative polymerase chain reaction and immunohistochemistry. The predominant mechanism of action was nuclear factor kappa B signaling and type 2 immune response. However, salivary gland epithelial cell activation, activation of mast cells, type 1 immune response, and upregulated angiogenesis are crucial in mediating IL-33/ST2 signaling in oral diseases.

CONCLUSIONS

Accumulating evidence demonstrates that the IL-33/ST2 axis is a fundamental pathogenetic mechanism of oral diseases of inflammatory, autoimmune, or neoplastic origin.

Serum interleukin-33 and soluble suppression of tumorigenicity 2 in pediatric leukemia with febrile neutropenia

The purpose of this study was to evaluate the association between interleukin-33 (IL-33) and its receptor Soluble Suppression of Tumorigenicity-2 (sST2) levels and bacterial infections during febrile neutropenia (FN) in pediatric patients with acute lymphoblastic leukemia (ALL). In this prospective, case-control study, participants were divided into 3 groups: ALL patients with FN (Group A), ALL patients without neutropenia and fever (Group B), and healthy children without infection and chronic disease (Group C). There were 30 cases in each group. Blood samples for IL-33 and sST2 have been drawn from patients in Group A before the initiation of treatment and on days 1 and 5 of treatment, and from patients in Groups B and C at initiation. At admission, mean IL-33 level (39.02 ± 26.40 ng/L) in Group B and mean sST2 level (185.3 ± 371.49 ng/ml) in Group A were significantly higher than the other groups (p = 0.038, p < 0.001, respectively). No difference was observed in the mean IL-33 and sST2 levels in the 5-day follow-up of patients in Group A (p = 0.82, p = 0.86, respectively). IL-33 and sST2 levels were not associated with fever duration, neutropenia duration or length of hospitalization. While C-reactive protein (CRP) was significantly higher in patients with positive blood culture (p = 0.021), IL-33 (p = 0.49) and sST2 (p = 0.21) levels were not associated with culture positivity.  Conclusion: IL-33 and sST2 levels were not found valuable as diagnostic and prognostic markers to predict bacterial sepsis in patients with FN. What is Known: • Neutropenic patients are at high risk of serious bacterial and viral infections, but the admission symptom is often only fever. • Febrile neutropenia has a high mortality rate if not treated effectively. What is New: • Febrile neutropenia is not only caused by bacterial infections. Therefore, new biomarkers should be identified to prevent overuse of antibiotics. • Specific biomarkers are needed to diagnose bacterial sepsis in the early phase of febrile neutropenia.

Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of PF-06817024 in Healthy Participants, Participants with Chronic Rhinosinusitis with Nasal Polyps, and Participants with Atopic Dermatitis: A Phase 1, Randomized, Double-Blind, Placebo-Controlled Study

PF-06817024 is a high affinity, humanized antibody that binds interleukin-33, a proinflammatory type 2 cytokine, and thereby has the potential to inhibit downstream type 2 inflammation. This Phase 1, randomized, placebo-controlled study was conducted in 3 parts to evaluate the safety, tolerability, pharmacokinetics (PK), immunogenicity, and pharmacodynamics of escalating single and limited repeat PF-06817024 doses in healthy participants (Part 1), a single dose of PF-06817024 in participants with chronic rhinosinusitis with nasal polyps (Part 2), and repeat doses of PF-06817024 in participants with moderate to severe atopic dermatitis (atoptic dermatitis; Part 3). PF-06817024 was generally well tolerated in all participant populations. Most participants experienced a treatment-emergent adverse event (healthy participants, 78.4% and 100%; participants with chronic rhinosinusitis with nasal polyps, 90.9% and 88.9%; and participants with atoptic dermatitis, 60.0% and 62.5% in the PF-06817024 and placebo groups, respectively). No substantial deviations from dose proportionality were observed for single intravenous doses of 10-1000 mg, indicating linear PK in healthy participants. Mean terminal half-life ranged from 83 to 94 days after single intravenous administration in healthy participants and was similar to that observed after administration in the studied patient populations. Incidences of antidrug antibodies in the studied populations were 10.8%, 9.1%, and 5.0% for healthy participants, participants with chronic rhinosinusitis with nasal polyps, and participants with atoptic dermatitis, respectively. In addition, dose-dependent increases were observed in total serum interleukin-33 levels of treated participants, indicating target engagement. Overall, the PK and safety profile of PF-06817024 supports further investigation of the drug as a potential treatment for allergic diseases.

IL-10 Differentially Promotes Mast Cell Responsiveness to IL-33, Resulting in Enhancement of Type 2 Inflammation and Suppression of Neutrophilia

Mast cells (MCs) play critical roles in the establishment of allergic diseases. We recently demonstrated an unexpected, proinflammatory role for IL-10 in regulating MC responses. IL-10 enhanced MC activation and promoted IgE-dependent responses during food allergy. However, whether these effects extend to IgE-independent stimuli is not clear. In this article, we demonstrate that IL-10 plays a critical role in driving IL-33-mediated MC responses. IL-10 stimulation enhanced MC expansion and degranulation, ST2 expression, IL-13 production, and phospho-relA upregulation in IL-33-treated cells while suppressing TNF-α. These effects were partly dependent on endogenous IL-10 and further amplified in MCs coactivated with both IL-33 and IgE/Ag. IL-10's divergent effects also extended in vivo. In a MC-dependent model of IL-33-induced neutrophilia, IL-10 treatment enhanced MC responsiveness, leading to suppression of neutrophils and decreased TNF-α. In contrast, during IL-33-induced type 2 inflammation, IL-10 priming exacerbated MC activity, resulting in MC recruitment to various tissues, enhanced ST2 expression, induction of hypothermia, recruitment of eosinophils, and increased MCPT-1 and IL-13 levels. Our data elucidate an important role for IL-10 as an augmenter of IL-33-mediated MC responses, with implications during both allergic diseases and other MC-dependent disorders. IL-10 induction is routinely used as a prognostic marker of disease improvement. Our data suggest instead that IL-10 can enhance ST2 responsiveness in IL-33-activated MCs, with the potential to both aggravate or suppress disease severity depending on the inflammatory context.

Salivary IL-33 and sST2 levels in relation to TLR2 rs111200466 polymorphism and periodontitis

OBJECTIVES

Toll-like receptor-2 (TLR2) signalling pathway is involved in the regulation of interleukin (IL)-33 and its receptor suppression of tumorigenicity-2 (ST2). This study aimed to compare salivary IL-33 and soluble ST2 (sST2) levels of periodontitis patients with those of periodontally healthy individuals in relation to their TLR2 rs111200466 23-bp insertion/deletion polymorphism within the promoter region.

MATERIALS AND METHODS

Unstimulated saliva samples were collected, and periodontal parameters were recorded from 35 periodontally healthy individuals and 44 periodontitis patients. Non-surgical treatments were applied to periodontitis patients, and sample collections and clinical measurements were repeated 3 months following therapy. Salivary IL-33 and sST2 levels were measured with enzyme-linked immunosorbent assay kits, and TLR2 rs111200466 polymorphism was detected by polymerase chain reaction.

RESULTS

Elevated salivary IL-33 (p = 0.007) and sST2 (p = 0.020) levels were observed in periodontitis patients, in comparison to controls. sST2 levels declined 3-months following treatment (p < 0.001). Increased salivary IL-33 and sST2 levels were found to be associated with periodontitis, with no significant relation to the TLR2 polymorphism.

CONCLUSION

Periodontitis, but not TLR2 rs111200466 polymorphism, is associated with elevated salivary sST2 and possibly IL-33 levels, and periodontal treatment is effective in reducing salivary sST2 levels.

Decoding the potential role of regulatory T cells in sepsis-induced immunosuppression

Sepsis, a multiorgan dysfunction with high incidence and mortality, is caused by an imbalanced host-to-infection immune response. Organ-support therapy improves the early survival rate of sepsis patients. In the long term, those who survive the "cytokine storm" and its secondary damage usually show higher susceptibility to secondary infections and sepsis-induced immunosuppression, in which regulatory T cells (Tregs) are evidenced to play an essential role. However, the potential role and mechanism of Tregs in sepsis-induced immunosuppression remains elusive. In this review, we elucidate the role of different functional subpopulations of Tregs during sepsis and then review the mechanism of sepsis-induced immunosuppression from the aspects of regulatory characteristics, epigenetic modification, and immunometabolism of Tregs. Thoroughly understanding how Tregs impact the immune system during sepsis may shed light on preclinical research and help improve the translational value of sepsis immunotherapy.

From periphery to center stage: 50 years of advancements in innate immunity

Over the past 50 years in the field of immunology, something of a Copernican revolution has happened. For a long time, immunologists were mainly concerned with what is termed adaptive immunity, which involves the exquisitely specific activities of lymphocytes. But the other arm of immunity, so-called "innate immunity," had been neglected. To celebrate Cell's 50th anniversary, we have put together a review of the processes and components of innate immunity and trace the seminal contributions leading to the modern state of this field. Innate immunity has joined adaptive immunity in the center of interest for all those who study the body's defenses, as well as homeostasis and pathology. We are now entering the era where therapeutic targeting of innate immune receptors and downstream signals hold substantial promise for infectious and inflammatory diseases and cancer.

Prothrombotic autoantibodies targeting platelet factor 4/polyanion are associated with pediatric cerebral malaria

BACKGROUNDFeatures of consumptive coagulopathy and thromboinflammation are prominent in cerebral malaria (CM). We hypothesized that thrombogenic autoantibodies contribute to a procoagulant state in CM.METHODSPlasma from children with uncomplicated malaria (UM) (n = 124) and CM (n = 136) was analyzed by ELISA for a panel of 8 autoantibodies including anti-platelet factor 4/polyanion (anti-PF4/P), anti-phospholipid, anti-phosphatidylserine, anti-myeloperoxidase, anti-proteinase 3, anti-dsDNA, anti-β-2-glycoprotein I, and anti-cardiolipin. Plasma samples from individuals with nonmalarial coma (NMC) (n = 49) and healthy controls (HCs) (n = 56) were assayed for comparison. Associations with clinical and immune biomarkers were determined using univariate and logistic regression analyses.RESULTSMedian anti-PF4/P and anti-PS IgG levels were elevated in individuals with malaria infection relative to levels in HCs (P < 0.001) and patients with NMC (PF4/P: P < 0.001). Anti-PF4/P IgG levels were elevated in children with CM (median = 0.27, IQR: 0.19-0.41) compared with those with UM (median = 0.19, IQR: 0.14-0.22, P < 0.0001). Anti-PS IgG levels did not differ between patients with UM and those with CM (P = 0.39). When patients with CM were stratified by malaria retinopathy (Ret) status, the levels of anti-PF4/P IgG correlated negatively with the peripheral platelet count in patients with Ret+ CM (Spearman's rho [Rs] = 0.201, P = 0.04) and associated positively with mortality (OR = 15.2, 95% CI: 1.02-275, P = 0.048). Plasma from patients with CM induced greater platelet activation in an ex vivo assay relative to plasma from patients with UM (P = 0.02), and the observed platelet activation was associated with anti-PF4/P IgG levels (Rs= 0.293, P = 0.035).CONCLUSIONSThrombosis mediated by elevated anti-PF4/P autoantibodies may be one mechanism contributing to the clinical complications of CM.

Conjugation of IL-33 to Microporous Annealed Particle Scaffolds Enhances Type 2-Like Immune Responses In Vitro and In Vivo

The inflammatory foreign body response (FBR) is the main driver of biomaterial implant failure. Current strategies to mitigate the onset of a FBR include modification of the implant surface, release of anti-inflammatory drugs, and cell-scale implant porosity. The microporous annealed particle (MAP) scaffold platform is an injectable, porous biomaterial composed of individual microgels, which are annealed in situ to provide a structurally stable scaffold with cell-scale microporosity. MAP scaffold does not induce a discernible foreign body response in vivo and, therefore, can be used a "blank canvas" for biomaterial-mediated immunomodulation. Damage associated molecular patterns (DAMPs), such as IL-33, are potent regulators of type 2 immunity that play an important role in tissue repair. In this manuscript, IL-33 is conjugated to the microgel building-blocks of MAP scaffold to generate a bioactive material (IL33-MAP) capable of stimulating macrophages in vitro via a ST-2 receptor dependent pathway and modulating immune cell recruitment to the implant site in vivo, which indicates an upregulation of a type 2-like immune response and downregulation of a type 1-like immune response.

IL-33 Induces Cellular and Exosomal miR-146a Expression as a Feedback Inhibitor of Mast Cell Function

IL-33 is an inflammatory cytokine that promotes allergic disease by activating group 2 innate lymphoid cells, Th2 cells, and mast cells. IL-33 is increased in asthmatics, and its blockade suppresses asthma-like inflammation in mouse models. Homeostatic control of IL-33 signaling is poorly understood. Because the IL-33 receptor, ST2, acts via cascades used by the TLR family, similar feedback mechanisms may exist. MicroRNA (miR)-146a is induced by LPS-mediated TLR4 signaling and serves as a feedback inhibitor. Therefore, we explored whether miR-146a has a role in IL-33 signaling. IL-33 induced cellular and exosomal miR-146a expression in mouse bone marrow-derived mast cells (BMMCs). BMMCs transfected with a miR-146a antagonist or derived from miR-146a knockout mice showed enhanced cytokine expression in response to IL-33, suggesting that miR-146a is a negative regulator of IL-33-ST2 signaling. In vivo, miR-146a expression in plasma exosomes was elevated after i.p. injection of IL-33 in wild-type but not mast cell-deficient KitW-sh/W-sh mice. Finally, KitW-sh/W-sh mice acutely reconstituted with miR-146a knockout BMMCs prior to IL-33 challenge had elevated plasma IL-6 levels compared with littermates receiving wild-type BMMCs. These results support the hypothesis that miR-146a is a feedback regulator of IL-33-mediated mast cell functions associated with allergic disease.

Exploratory mass cytometry analysis reveals immunophenotypes of cancer treatment-related pneumonitis

Anticancer treatments can result in various adverse effects, including infections due to immune suppression/dysregulation and drug-induced toxicity in the lung. One of the major opportunistic infections is Pneumocystis jirovecii pneumonia (PCP), which can cause severe respiratory complications and high mortality rates. Cytotoxic drugs and immune-checkpoint inhibitors (ICIs) can induce interstitial lung diseases (ILDs). Nonetheless, the differentiation of these diseases can be difficult, and the pathogenic mechanisms of such diseases are not yet fully understood. To better comprehend the immunophenotypes, we conducted an exploratory mass cytometry analysis of immune cell subsets in bronchoalveolar lavage fluid from patients with PCP, cytotoxic drug-induced ILD (DI-ILD), and ICI-associated ILD (ICI-ILD) using two panels containing 64 markers. In PCP, we observed an expansion of the CD16+ T cell population, with the highest CD16+ T proportion in a fatal case. In ICI-ILD, we found an increase in CD57+ CD8+ T cells expressing immune checkpoints (TIGIT+ LAG3+ TIM-3+ PD-1+), FCRL5+ B cells, and CCR2+ CCR5+ CD14+ monocytes. These findings uncover the diverse immunophenotypes and possible pathomechanisms of cancer treatment-related pneumonitis.

Copaiba oil minimizes inflammation and promotes parenchyma re-epithelization in acute allergic asthma model induced by ovalbumin in BALB/c mice

Introduction: Asthma is a condition of airflow limitation, common throughout the world, with high mortality rates, especially as it still faces some obstacles in its management. As it constitutes a public health challenge, this study aimed to investigate the effect of copaiba oil (e.g., Copaifera langsdorffii), as a treatment resource, at doses of 50 and 100 mg/kg on certain mediators of acute lung inflammation (IL-33, GATA3, FOXP3, STAT3, and TBET) and early mechanisms of lung remodeling (degradation of elastic fiber tissues, collagen deposition, and goblet cell hyperplasia). Methods: Using an ovalbumin-induced acute allergic asthma model in BALB/c mice, we analyzed the inflammatory mediators through immunohistochemistry and the mechanisms of lung remodeling through histopathology, employing orcein, Masson's trichrome, and periodic acid-Schiff staining. Results: Copaiba oil treatment (CO) reduced IL-33 and increased FOXP3 by stimulating the FOXP3/GATA3 and FOXP3/STAT3 pathways. Additionally, it upregulated TBET, suggesting an additional role in controlling GATA3 activity. In the respiratory epithelium, CO decreased the fragmentation of elastic fibers while increasing the deposition of collagen fibers, favoring epithelial restructuring. Simultaneously, CO reduced goblet cell hyperplasia. Discussion: Although additional research is warranted, the demonstrated anti-inflammatory and re-epithelializing action makes CO a viable option in exploring new treatments for acute allergic asthma.

The diagnostic value of sST2 for myocardial fibrosis in idiopathic inflammatory myopathies in subclinical stage of cardiac involvement

OBJECTIVE

Myocardial fibrosis occurs in the early subclinical stage of cardiac involvement in idiopathic inflammatory myopathies (IIMs). Soluble suppression of tumorigenicity 2 (sST2) is known to have an immunomodulatory impact during autoimmune disease development. The current study investigated the diagnostic value of sST2 for myocardial fibrosis during early stage of cardiac involvement in IIM.

METHODS

A total of 44 IIM patients with normal heart function and 32 age- and gender-matched healthy controls (HCs) were enrolled. Serum sST2 levels were measured by ELISA and cardiac magnetic resonance (CMR) parameters for myocardial fibrosis [native T1, extracellular volume (ECV), late-gadolinium enhancement (LGE)] and oedema (T2 values) were analysed.

RESULTS

IIM patients had significantly higher sST2 levels than HCs [67.5 ng/ml (s.d. 30.4)] vs 14.4 (5.5), P < 0.001] and levels correlated positively with diffuse myocardial fibrosis parameters, native T1 (r = 0.531, P = 0.000), ECV (r = 0.371, P = 0.013) and focal myocardial fibrosis index and LGE (r = 0.339, P = 0.024) by Spearman's correlation analysis. sST2 was an independent predictive factor for diffuse and focal myocardial fibrosis after adjustment for age, gender, BMI and ESR. Risk increased ≈15.4% for diffuse [odds ratio (OR) 1.154 (95% CI 1.021, 1.305), P = 0.022] and 3.8% for focal [OR 1.038 (95% CI 1.006, 1.072), P = 0.020] myocardial fibrosis per unit increase of sST2. Cut-off values for diagnosing diffuse and focal myocardial fibrosis were sST2 ≥51.3 ng/ml [area under the curve (AUC) = 0.942, sensitivity = 85.7%, specificity = 98.9%, P < 0.001] and 53.3 ng/ml (AUC = 0.753, sensitivity = 87.5%, specificity = 58.3%, P < 0.01), respectively.

CONCLUSION

sST2 showed a marked elevation during the subclinical stage of cardiac involvement in IIM and has potential as a biomarker for predicting diffuse and focal myocardial fibrosis in IIM.

Topical application of activator protein-1 inhibitor T-5224 suppresses inflammation and improves skin barrier function in a murine atopic dermatitis-like dermatitis

BACKGROUND

Selective activator protein (AP)-1 inhibitors are potentially promising therapeutic agents for atopic dermatitis (AD) because AP-1 is an important regulator of skin inflammation. However, few studies have investigated the effect of topical application of AP-1 inhibitors in treating inflammatory skin disorders.

METHODS

Immunohistochemistry was conducted to detect phosphorylated AP-1/c-Jun expression of skin lesions in AD patients. In the in vivo study, 1 % T-5224 ointment was topically applied for 8 days to the ears of 2,4 dinitrofluorobenzene challenged AD-like dermatitis model mice. Baricitinib, a conventional therapeutic agent Janus kinase (JAK) inhibitor, was also topically applied. In the in vitro study, human epidermal keratinocytes were treated with T-5224 and stimulated with AD-related cytokines.

RESULTS

AP-1/c-Jun was phosphorylated at skin lesions in AD patients. In vivo, topical T-5224 application inhibited ear swelling (P < 0.001), restored filaggrin (Flg) expression (P < 0.01), and generally suppressed immune-related pathways. T-5224 significantly suppressed Il17a and l17f expression, whereas baricitinib did not. Baricitinib suppressed Il4, Il19, Il33 and Ifnb expression, whereas T-5224 did not. Il1a, Il1b, Il23a, Ifna, S100a8, and S100a9 expression was cooperatively downregulated following the combined use of T-5224 and baricitinib. In vitro, T-5224 restored the expression of FLG and loricrin (LOR) (P < 0.05) and suppressed IL33 expression (P < 0.05) without affecting cell viability and cytotoxicity.

CONCLUSIONS

Topical T-5224 ameliorates clinical manifestations of AD-like dermatitis in mice. The effect of this inhibitor is amplified via combined use with JAK inhibitors.

Pathogenesis-based application of biologics for chronic rhinosinusitis: Current and future perspectives

Chronic rhinosinusitis (CRS) is heterogeneous and contains diverse pathogenesis including type 1, type 2, and/or type 3 inflammation. For severe type 2 CRS especially CRS with nasal polyps (CRSwNP), biologics that target inflammatory molecules have recently been applied along with further changes in the treatment algorithm for CRS. Currently, a completed phase 3 clinical trial for biologics for severe CRSwNP with inadequate response to surgery and/or intranasal corticosteroids, including omalizumab (anti-IgE), mepolizumab (anti-IL-5), benralizumab (anti-IL-5Rα), and dupilumab (anti-IL-4Rα), have all shown efficacy. Similar phase 3 clinical trials for tezepelumab (anti-TSLP) and etokimab (anti-IL-33) are now underway and completed, respectively. Further studies need to evaluate how to optimally and cost-effectively use biologics for CRS and determine if any biomarkers are indicative of which biologics should be administered. A definition of complete and/or clinical remission of CRS is also needed to determine when to reduce or discontinue biologics. In addition, more precise basic research on CRS, such as endotyping and genotyping, will need to be undertaken in order to determine novel targets for biologics.

Interleukin-33/serum stimulation-2 pathway: Regulatory mechanisms and emerging implications in immune and inflammatory diseases

Interleukin (IL)- 33, a nuclear factor and pleiotropic cytokine of the IL-1 family, is gaining attention owing to its important role in chronic inflammatory and autoimmune diseases. This review extends our knowledge of the effects exerted by IL-33 on target cells by binding to its specific receptor serum stimulation-2 (ST2). Depending on the tissue context, IL-33 performs multiple functions encompassing host defence, immune response, initiation and amplification of inflammation, tissue repair, and homeostasis. The levels and activity of IL-33 in the body are controlled by complex IL-33-targeting regulatory pathways. The unique temporal and spatial expression patterns of IL-33 are associated with host homeostasis and the development of immune and inflammatory disorders. Therefore, understanding the origin, function, and processes of IL-33 under various conditions is crucial. This review summarises the regulatory mechanisms underlying the IL-33/ST2 signalling axis and its potential role and clinical significance in immune and inflammatory diseases, and discusses the current complex and conflicting findings related to IL-33 in host responses.

The IL-33/ST2 axis is protective against acute inflammation during the course of periodontitis

Periodontitis, which is induced by repeated bacterial invasion and the ensuing immune reactions that follow, is the leading cause of tooth loss. Periodontal tissue is comprised of four different components, each with potential role in pathogenesis, however, most studies on immune responses focus on gingival tissue. Here, we present a modified ligature-induced periodontitis model in male mice to analyze the pathogenesis, which captures the complexity of periodontal tissue. We find that the inflammatory response in the peri-root tissues and the expression of IL-6 and RANKL by Thy-1.2- fibroblasts/stromal cells are prominent throughout the bone destruction phase, and present already at an early stage. The initiation phase is characterized by high levels of ST2 (encoded by Il1rl1) expression in the peri-root tissue, suggesting that the IL-33/ST2 axis is involved in the pathogenesis. Both Il1rl1- and Il33-deficient mice exhibit exacerbated bone loss in the acute phase of periodontitis, along with macrophage polarization towards a classically activated phenotype and increased neutrophil infiltration, indicating a protective role of the IL-33/ST2 axis in acute inflammation. Thus, our findings highlight the hidden role of the peri-root tissue and simultaneously advance our understanding of the etiology of periodontitis via implicating the IL-33/ST2 axis.

The ST2+ Treg/amphiregulin axis protects from immune-mediated hepatitis

Introduction

The alarmin IL-33 has been implicated in the pathology of immune-mediated liver diseases. IL-33 activates regulatory T cells (Tregs) and type 2 innate lymphoid cells (ILC2s) expressing the IL-33 receptor ST2. We have previously shown that endogenous IL-33/ST2 signaling activates ILC2s that aggravate liver injury in murine immune-mediated hepatitis. However, treatment of mice with exogenous IL-33 before induction of hepatitis ameliorated disease severity. Since IL-33 induces expression of amphiregulin (AREG) crucial for Treg function, we investigated the immunoregulatory role of the ST2+ Treg/AREG axis in immune-mediated hepatitis.

Methods

C57BL/6, ST2-deficient (Il1rl1-/-) and Areg-/- mice received concanavalin A to induce immune-mediated hepatitis. Foxp3Cre+ x ST2fl/fl mice were pre-treated with IL-33 before induction of immune-mediated hepatitis. Treg function was assessed by adoptive transfer experiments and suppression assays. The effects of AREG and IL-33 on ST2+ Tregs and ILC2s were investigated in vitro. Immune cell phenotype was analyzed by flow cytometry.

Results and discussion

We identified IL-33-responsive ST2+ Tregs as an effector Treg subset in the murine liver, which was highly activated in immune-mediated hepatitis. Lack of endogenous IL-33 signaling in Il1rl1-/- mice aggravated disease pathology. This was associated with reduced Treg activation. Adoptive transfer of exogenous IL-33-activated ST2+ Tregs before induction of hepatitis suppressed inflammatory T-cell responses and ameliorated disease pathology. We further showed increased expression of AREG by hepatic ST2+ Tregs and ILC2s in immune-mediated hepatitis. Areg-/- mice developed more severe liver injury, which was associated with enhanced ILC2 activation and less ST2+ Tregs in the inflamed liver. Exogenous AREG suppressed ILC2 cytokine expression and enhanced ST2+ Treg activation in vitro. In addition, Tregs from Areg-/- mice were impaired in their capacity to suppress CD4+ T-cell activation in vitro. Moreover, application of exogenous IL-33 before disease induction did not protect Foxp3Cre+ x ST2fl/fl mice lacking ST2+ Tregs from immune-mediated hepatitis. In summary, we describe an immunoregulatory role of the ST2+ Treg/AREG axis in immune-mediated hepatitis, in which AREG suppresses the activation of hepatic ILC2s while maintaining ST2+ Tregs and reinforcing their immunosuppressive capacity in liver inflammation.

Potential anti-tumor effects of regulatory T cells in the tumor microenvironment: a review

Regulatory T cells (Tregs) expressing the transcription factor FoxP3 are essential for maintaining immunological balance and are a significant component of the immunosuppressive tumor microenvironment (TME). Single-cell RNA sequencing (ScRNA-seq) technology has shown that Tregs exhibit significant plasticity and functional diversity in various tumors within the TME. This results in Tregs playing a dual role in the TME, which is not always centered around supporting tumor progression as typically believed. Abundant data confirms the anti-tumor activities of Tregs and their correlation with enhanced patient prognosis in specific types of malignancies. In this review, we summarize the potential anti-tumor actions of Tregs, including suppressing tumor-promoting inflammatory responses and boosting anti-tumor immunity. In addition, this study outlines the spatial and temporal variations in Tregs function to emphasize that their predictive significance in malignancies may change. It is essential to comprehend the functional diversity and potential anti-tumor effects of Tregs to improve tumor therapy strategies.

Obese visceral adipose dendritic cells downregulate regulatory T cell development through IL-33

Regulatory T cells (Tregs) residing in visceral adipose tissue (VAT) play a pivotal role in regulating tissue inflammation and metabolic dysfunction associated with obesity. However, the specific phenotypic and functional characteristics of Tregs in obese VAT, as well as the regulatory mechanisms shaping them, remain elusive. This study demonstrates that obesity selectively reduces Tregs in VAT, characterized by restrained proliferation, heightened PD-1 expression, and diminished ST2 expression. Additionally, obese VAT displays distinctive maturation of dendritic cells (DCs), marked by elevated expressions of MHC-II, CD86, and PD-L1, which are inversely correlated with VAT Tregs. In an in vitro co-culture experiment, only obese VAT DCs, not macrophages or DCs from subcutaneous adipose tissue (SAT) and spleen, result in decreased Treg differentiation and proliferation. Furthermore, Tregs differentiated by obese VAT DCs exhibit distinct characteristics resembling those of Tregs in obese VAT, such as reduced ST2 and IL-10 expression. Mechanistically, obesity lowers IL-33 production in VAT DCs, contributing to the diminished Treg differentiation. These findings collectively underscore the critical role of VAT DCs in modulating Treg generation and shaping Treg phenotype and function during obesity, potentially contributing to the regulation of VAT Treg populations.

IL-33 aggravates extranodal NK/T cell lymphoma aggressiveness and angiogenesis by activating the Wnt/β-catenin signaling pathway

Extranodal NK/T cell lymphoma (ENKTCL) is an extremely aggressive form of lymphoma and lacks of specific diagnostic markers. The study intended to unearth the role of interleukin-33 (IL-33) in ENKTCL. RT-qPCR was conducted to assess mRNA levels of ENKTCL tissues and cells, while western blot assay was performed for evaluating protein levels. Plate cloning experiment and transwell assay were employed to measure aggressiveness of ENKTCL. Tube formation assay was executed to determine the angiogenesis ability. Mice ENKTCL xenograft model was designed to probe the impacts of IL-33 in vivo. IL-33 and suppression of tumorigenicity 2 receptor (ST2, receptor of IL-33) were enhanced in ENKTCL. IL-33 inhibition suppressed viability, migration, and invasion of ENKTCL cells. Moreover, IL-33 knockdown restricted angiogenesis in human umbilical vein endothelial cells (HUVECs). Furthermore, Wnt/β-catenin pathway associated proteins (β-catenin, c-myc, and cyclin D1) were downregulated by loss of IL-33. However, these impacts were overturned by Wnt/β-catenin signaling agonist lithium chloride (LiCl). Additionally, IL-33 silencing exerted anti-tumor effect via Wnt/β-catenin pathway in vivo. Silencing of IL-33 inhibited ENKTCL tumorigenesis and angiogenesis by inactivating Wnt/β-catenin signaling pathway. As such, IL-33 might be a prospective treatment target for ENKTCL.

Intersection of Immunity, Metabolism, and Muscle Regeneration in an Autoimmune-Prone MRL Mouse Model

Due to the limited capacity of mammals to regenerate complex tissues, researchers have worked to understand the mechanisms of tissue regeneration in organisms that maintain that capacity. One example is the MRL/MpJ mouse strain with unique regenerative capacity in ear pinnae that is absent from other strains, such as the common C57BL/6 strain. The MRL/MpJ mouse has also been associated with an autoimmune phenotype even in the absence of the mutant Fas gene described in its parent strain MRL/lpr. Due to these findings, the differences between the responses of MRL/MpJ versus C57BL/6 strain are evaluated in volumetric muscle injury and subsequent material implantation. One salient feature of the MRL/MpJ response to injury is robust adipogenesis within the muscle. This is associated with a decrease in M2-like polarization in response to biologically derived extracellular matrix scaffolds. In pro-fibrotic materials, such as polyethylene, there are fewer foreign body giant cells in the MRL/MpJ mice. As there are reports of both positive and negative influences of adipose tissue and adipogenesis on wound healing, this model can provide an important lens to investigate the interplay between stem cells, adipose tissue, and immune responses in trauma and material implantation.

The role of IL-19, IL-24, IL-21 and IL-33 in intestinal mucosa of inflammatory bowel disease: A narrative review

Interleukins are potential therapeutic targets that can alter the prognosis and progression of inflammatory bowel disease (IBD). The roles of IL-6, IL-10, IL-17, and IL-23 have been extensively studied, setting the stage for the development of novel treatments for patients with IBD. Other cytokines have been less extensively studied. Members of the IL-20 family, mainly IL-19 and IL-24, are involved in the pathogenesis of IBD, but their exact role remains unclear. Similarly, IL-33, a newly identified cytokine, has been shown to control the Th1 effector response and the action of colonic Tregs in animal models of colitis and patients with IBD. IL-21 is involved in the Th1, Th2, and Th17 responses. Data support a promising future use of these interleukins as biomarkers of severe diseases and as potential therapeutic targets for novel monoclonal antibodies. This review aims to summarize the existing studies involving animal models of colitis and patients with IBD to clarify their role in the intestinal mucosa.

Innate Lymphoid Cells in Bladder Cancer: From Mechanisms of Action to Immune Therapies

Bladder tumors have a high mutational burden and tend to be responsive to immune therapies; however, response rates remain modest. To date, immunotherapy in bladder cancer has largely focused on enhancing T-cell immune responses in the bladder tumor microenvironment. It is anticipated that other immune cells, including innate lymphoid cells (ILC), which play an important role in bladder oncogenesis and tumor suppression, could be targeted to improve response to existing therapies. ILCs are classified into five groups: natural killer cells, ILC1s, ILC2s, ILC3s, and lymphoid tissue inducer cells. ILCs are pleiotropic and play dual and sometimes paradoxical roles in cancer development and progression. Here, a comprehensive discussion of the current knowledge and recent advancements in understanding the role of ILCs in bladder cancer is provided. We discuss the multifaceted roles that ILCs play in bladder immune surveillance, tumor protection, and immunopathology of bladder cancer. This review provides a rationale for targeting ILCs in bladder cancer, which is relevant for other solid tumors.

A type 1 immunity-restricted promoter of the IL-33 receptor gene directs antiviral T-cell responses

The pleiotropic alarmin interleukin-33 (IL-33) drives type 1, type 2 and regulatory T-cell responses via its receptor ST2. Subset-specific differences in ST2 expression intensity and dynamics suggest that transcriptional regulation is key in orchestrating the context-dependent activity of IL-33-ST2 signaling in T-cell immunity. Here, we identify a previously unrecognized alternative promoter in mice and humans that is located far upstream of the curated ST2-coding gene and drives ST2 expression in type 1 immunity. Mice lacking this promoter exhibit a selective loss of ST2 expression in type 1- but not type 2-biased T cells, resulting in impaired expansion of cytotoxic T cells (CTLs) and T-helper 1 cells upon viral infection. T-cell-intrinsic IL-33 signaling via type 1 promoter-driven ST2 is critical to generate a clonally diverse population of antiviral short-lived effector CTLs. Thus, lineage-specific alternative promoter usage directs alarmin responsiveness in T-cell subsets and offers opportunities for immune cell-specific targeting of the IL-33-ST2 axis in infections and inflammatory diseases.

Macrophages reprogramming improves immunotherapy of IL-33 in peritoneal metastasis of gastric cancer

Peritoneal metastasis (PM) has a suppressive tumor immune microenvironment (TIME) that limits the effects of immunotherapy. This study aimed to investigate the immunomodulatory effects of intraperitoneal administration of IL-33, a cytokine that is reported to potentiate antitumor immunity and inhibit metastasis. We found survival was significantly prolonged in patients with high IL-33 mRNA expression. In immunocompetent mice, intraperitoneal administration of IL-33 could induce a celiac inflammatory environment, activate immunologic effector cells, and reverse the immunosuppressive tumor microenvironment, which effectively delayed tumor progression and PM of gastric cancer. Mechanistically, IL-33 could induce M2 polarization by activating p38-GATA-binding protein 3 signaling. IL-33 combined with anti-CSF1R or p38 inhibitor to regulate tumor-associated macrophages (TAMs) had a synergistic antitumor effect. Inducing a local inflammatory milieu by IL-33 administration provided a novel approach for treating peritoneal metastasis, which, when combined with TAM reprogramming to reshape TIME, can achieve better treatment efficacy.

Immunomodulation in non-alcoholic fatty liver disease: exploring mechanisms and applications

Non-alcoholic fatty liver disease (NAFLD) exhibits increased lipid enrichment in hepatocytes. The spectrum of this disease includes stages such as nonalcoholic simple fatty liver (NAFL), nonalcoholic steatohepatitis (NASH), and liver fibrosis. Changes in lifestyle behaviors have been a major factor contributing to the increased cases of NAFLD patients globally. Therefore, it is imperative to explore the pathogenesis of NAFLD, identify therapeutic targets, and develop new strategies to improve the clinical management of the disease. Immunoregulation is a strategy through which the organism recognizes and eliminates antigenic foreign bodies to maintain physiological homeostasis. In this process, multiple factors, including immune cells, signaling molecules, and cytokines, play a role in governing the evolution of NAFLD. This review seeks to encapsulate the advancements in research regarding immune regulation in NAFLD, spanning from underlying mechanisms to practical applications.

Nonspecific Orbital Inflammation (NSOI): Unraveling the Molecular Pathogenesis, Diagnostic Modalities, and Therapeutic Interventions

Nonspecific orbital inflammation (NSOI), colloquially known as orbital pseudotumor, sometimes presents a diagnostic and therapeutic challenge in ophthalmology. This review aims to dissect NSOI through a molecular lens, offering a comprehensive overview of its pathogenesis, clinical presentation, diagnostic methods, and management strategies. The article delves into the underpinnings of NSOI, examining immunological and environmental factors alongside intricate molecular mechanisms involving signaling pathways, cytokines, and mediators. Special emphasis is placed on emerging molecular discoveries and approaches, highlighting the significance of understanding molecular mechanisms in NSOI for the development of novel diagnostic and therapeutic tools. Various diagnostic modalities are scrutinized for their utility and limitations. Therapeutic interventions encompass medical treatments with corticosteroids and immunomodulatory agents, all discussed in light of current molecular understanding. More importantly, this review offers a novel molecular perspective on NSOI, dissecting its pathogenesis and management with an emphasis on the latest molecular discoveries. It introduces an integrated approach combining advanced molecular diagnostics with current clinical assessments and explores emerging targeted therapies. By synthesizing these facets, the review aims to inform clinicians and researchers alike, paving the way for molecularly informed, precision-based strategies for managing NSOI.

Inserting "OFF-to-ON" BODIPY Tags into Cytokines: A Fluorogenic Interleukin IL-33 for Real-Time Imaging of Immune Cells

The essential functions that cytokine/immune cell interactions play in tissue homeostasis and during disease have prompted the molecular design of targeted fluorophores to monitor their activity in real time. Whereas activatable probes for imaging immune-related enzymes are common, many immunological functions are mediated by binding events between cytokines and their cognate receptors that are hard to monitor by live-cell imaging. A prime example is interleukin-33 (IL-33), a key cytokine in innate and adaptive immunity, whose interaction with the ST2 cell-surface receptor results in downstream signaling and activation of NF-κB and AP-1 pathways. In the present work, we have designed a chemical platform to site-specifically introduce OFF-to-ON BODIPY fluorophores into full cytokine proteins and generate the first nativelike fluorescent analogues of IL-33. Among different incorporation strategies, chemical aminoacylation followed by bioorthogonal derivatization led to the best labeling results. Importantly, the BODIPY-labeled IL-33 derivatives-unlike IL-33-GFP constructs-exhibited ST2-specific binding and downstream bioactivity profiles comparable to those of the wild-type interleukin. Real-time fluorescence microscopy assays under no wash conditions confirmed the internalization of IL-33 through ST2 receptors and its intracellular trafficking through the endosomal pathway. We envision that the modularity and versatility of our BODIPY labeling platform will facilitate the synthesis of minimally tagged fluorogenic cytokines as the next generation of imaging reagents for real-time visualization of signaling events in live immune cells.

Serum levels of interleukin-33, soluble ST2 and IgE in patients with asthma: a case-control study

INTRODUCTION

Interleukins play a very important role in the pathophysiology of asthma. Interleukin-33 (IL-33) is a partially explored cytokine in asthma. It binds with a specific receptor called suppression of tumorigenicity 2 (ST2). The study aims to evaluate the serum levels of IL-33, sST2 and IgE in asthmatic patients and healthy controls and its further association with the forced expiratory volume in one second (FEV 1%) and absolute eosinophil count.

MATERIALS AND METHODS

We enrolled 100 asthmatic patients and 57 healthy subjects for the study. We measured serum levels of IgE, IL-33, and sST2. Based on serum IgE levels, patients were divided into allergic and non-allergic groups. Statistical analysis was done by using Graph pad prism software 8.

RESULTS

We found significantly elevated levels of IL-33 and IgE in asthmatic patients as compared to healthy subjects. However, sST2 levels were significantly lower in asthmatic patients than in healthy subjects. FEV1% values were decreased in uncontrolled asthmatic patients. In addition, serum levels of IL-33 were significantly correlated with the IgE. Furthermore, we found a significant correlation between IL-33 and AEC in allergic asthmatic patients.

CONCLUSION

In this study, we reported elevated IL-33 and IgE levels and decreased sST2 levels in asthmatic patients compared to healthy controls. IL-33 and sST2 may act as inflammatory biomarkers for allergic diseases such as asthma.

Multiple Protein Biomarkers and Different Treatment Strategies for Colorectal Carcinoma: A Comprehensive Prospective

In this review, we emphasized important biomarkers, pathogenesis, and newly developed therapeutic approaches in the treatment of colorectal cancer (CRC). This includes a complete description of small-molecule inhibitors, phytopharmaceuticals with antiproliferative potential, monoclonal antibodies for targeted therapy, vaccinations as immunotherapeutic agents, and many innovative strategies to intervene in the interaction of oncogenic proteins. Many factors combine to determine the clinical behavior of colorectal cancer and it is still difficult to comprehend the molecular causes of a person's vulnerability to CRC. It is also challenging to identify the causes of the tumor's onset, progression, and responsiveness or resistance to antitumor treatment. Current recommendations for targeted medications are being updated by guidelines throughout the world in light of the growing number of high-quality clinical studies. So, being concerned about the aforementioned aspects, we have tried to present a summarized pathogenic view, including a brief description of biomarkers and an update of compounds with their underlying mechanisms that are currently under various stages of clinical testing. This will help to identify gaps or shortfalls that can be addressed in upcoming colorectal cancer research.

Therapeutic Targets and Precision Medicine in COPD: Inflammation, Ion Channels, Both, or Neither?

The development of a wider range of therapeutic options is a key objective in drug discovery for chronic obstructive pulmonary disease (COPD). Fundamental advances in lung biology have the potential to greatly expand the number of therapeutic targets in COPD. The recently reported successful Phase 3 clinical trial of the first biologic agent for COPD, the monoclonal antibody dupilumab, adds additional support to the importance of targeting inflammatory pathways in COPD. However, numerous other cellular mechanisms are important targets in COPD therapeutics, including airway remodeling, the CFTR ion channel, and mucociliary function. Some of these emerging targets can be exploited by the expanded use of existing COPD drugs, such as roflumilast, while targeting others will require the development of novel molecular entities. The identification of additional therapeutic targets and agents has the potential to greatly expand the value of using clinical and biomarker data to classify COPD into specific subsets, each of which can be predictive of an enhanced response to specific subset(s) of targeted therapies. The author reviews established and emerging drug targets in COPD and uses this as a framework to define a novel classification of COPD based on therapeutic targets. This novel classification has the potential to enhance precision medicine in COPD patient care and to accelerate clinical trials and pre-clinical drug discovery efforts.

Role of IL-33-ST2 pathway in regulating inflammation: current evidence and future perspectives

Interleukin (IL)-33 is an alarmin of the IL-1 superfamily localized to the nucleus of expressing cells, such as endothelial cells, epithelial cells, and fibroblasts. In response to cellular damage or stress, IL-33 is released and activates innate immune responses in some immune and structural cells via its receptor interleukin-1 receptor like-1 (IL-1RL1 or ST2). Recently, IL-33 has become a hot topic of research because of its role in pulmonary inflammation. The IL-33-ST2 signaling pathway plays a pro-inflammatory role by activating the type 2 inflammatory response, producing type 2 cytokines and chemokines. Elevated levels of IL-33 and ST2 have been observed in chronic pulmonary obstructive disease (COPD). Notably, IL-33 is present in COPD induced by cigarette smoke or acute inflammations. The role of IL-33 in sepsis is becoming increasingly prominent, and understanding its significance in the treatment of sepsis associated with high mortality is critical. In addition to its pro-inflammatory effects, the IL-33-ST2 axis appears to play a role in bacterial clearance and tissue repair. In this review, we focused on the role of the IL-33-ST2 axis in sepsis, asthma, and COPD and summarized the therapeutic targets associated with this axis, providing a basis for future treatment.

IL-33/ST2L signaling alleviates diabetic nephropathy by regulating endoplasmic reticulum stress and apoptosis

OBJECTIVE

Diabetic nephropathy (DN) is a serious chronic complication of diabetes mellitus (DM). Endoplasmic reticulum (ER) stress is an important factor in the regulation of pathological processes in DN, and excessive ER stress can lead to apoptosis. Although the IL-33/ST2 axis is known to be involved in diabetic kidney disease or related nephropathy, its role and molecular mechanisms remain poorly understood in terms of DN. The purpose of this study was to investigate the effects of IL-33/ST2 signaling on DN and to characterize the roles that ER stress and apoptosis play in DN.

METHODS

To investigate this study, mice were randomly assigned into DN (induced by 0.1% STZ) and Control groups. Biochemical indices (FBG, BUN, UPR, UCE) were measured in serum and urine samples to reflect blood glucose and kidney damage. Quantitative real-time PCR, western blot, and immunofluorescence were used to assess gene and protein expression of the IL-33/ST2 axis and ER stress relative signaling molecule. Apoptosis was analyzed by flow cytometry.

RESULTS

IL-33 levels are significantly increased in the kidneys of patients and mice with DN. Double immunofluorescence staining showed that IL-33 colocalized with CD31-positive endothelial cells. Treatment with IL-33 attenuated kidney injury in Streptozotocin (STZ)-treated mice. In vitro, we showed that IL-33 attenuated ER stress and apoptosis in glomerular endothelial cells. However, sST2 treatment significantly reversed these effects of IL-33.

CONCLUSION

Together, these data suggest that IL-33/ST2 signaling mitigates STZ-induced renal damage, partly at least, by suppressing ER stress and apoptosis. Therefore, IL-33 may be an effective therapeutic target in DN.