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.

Interleukin-33 Promotes Serotonin Release from Enterochromaffin Cells for Intestinal Homeostasis.

The gastrointestinal tract is known as the largest endocrine organ that encounters and integrates various immune stimulations and neuronal responses due to constant environmental challenges. Enterochromaffin (EC) cells, which function as chemosensors on the gut epithelium, are known to translate environmental cues into serotonin (5-HT) production, contributing to intestinal physiology. However, how immune signals participate in gut sensation and neuroendocrine response remains unclear. Interleukin-33 (IL-33) acts as an alarmin cytokine by alerting the system of potential environmental stresses. We here demonstrate that IL-33 induced instantaneous peristaltic movement and facilitated Trichuris muris expulsion. We found that IL-33 could be sensed by EC cells, inducing release of 5-HT. IL-33-mediated 5-HT release activated enteric neurons, subsequently promoting gut motility. Mechanistically, IL-33 triggered calcium influx via a non-canonical signaling pathway specifically in EC cells to induce 5-HT secretion. Our data establish an immune-neuroendocrine axis in calibrating rapid 5-HT release for intestinal homeostasis.

Aryl Hydrocarbon Receptor Signaling Cell Intrinsically Inhibits Intestinal Group 2 Innate Lymphoid Cell Function.

Innate lymphoid cells (ILCs) are important for mucosal immunity. The intestine harbors all ILC subsets, but how these cells are balanced to achieve immune homeostasis and mount appropriate responses during infection remains elusive. Here, we show that aryl hydrocarbon receptor (Ahr) expression in the gut regulates ILC balance. Among ILCs, Ahr is most highly expressed by gut ILC2s and controls chromatin accessibility at the Ahr locus via positive feedback. Ahr signaling suppresses Gfi1 transcription-factor-mediated expression of the interleukin-33 (IL-33) receptor ST2 in ILC2s and expression of ILC2 effector molecules IL-5, IL-13, and amphiregulin in a cell-intrinsic manner. Ablation of Ahr enhances anti-helminth immunity in the gut, whereas genetic or pharmacological activation of Ahr suppresses ILC2 function but enhances ILC3 maintenance to protect the host from Citrobacter rodentium infection. Thus, the host regulates the gut ILC2-ILC3 balance by engaging the Ahr pathway to mount appropriate immunity against various pathogens.

Hypoxia induces downregulation of the tumor-suppressive sST2 in colorectal cancer cells via the HIF-nuclear IL-33-GATA3 pathway.

As a decoy receptor, soluble ST2 (sST2) interferes with the function of the inflammatory cytokine interleukin (IL)-33. Decreased sST2 expression in colorectal cancer (CRC) cells promotes tumor growth via IL-33-mediated bioprocesses in the tumor microenvironment. In this study, we discovered that hypoxia reduced sST2 expression in CRC cells and explored the associated molecular mechanisms, including the expression of key regulators of ST2 gene transcription in hypoxic CRC cells. In addition, the effect of the recovery of sST2 expression in hypoxic tumor regions on malignant progression was investigated using mouse CRC cells engineered to express sST2 in response to hypoxia. Our results indicated that hypoxia-dependent increases in nuclear IL-33 interfered with the transactivation activity of GATA3 for ST2 gene transcription. Most importantly, hypoxia-responsive sST2 restoration in hypoxic tumor regions corrected the inflammatory microenvironment and suppressed tumor growth and lung metastasis. These results indicate that strategies targeting sST2 in hypoxic tumor regions could be effective for treating malignant CRC.

Knockout of the intellectual disability-linked gene Hs6st2 in mice decreases heparan sulfate 6-O-sulfation, impairs dendritic spines of hippocampal neurons, and affects memory.

Heparan sulfate (HS) is a linear polysaccharide that plays a key role in cellular signaling networks. HS functions are regulated by its 6-O-sulfation, which is catalyzed by three HS 6-O-sulfotransferases (HS6STs). Notably, HS6ST2 is mainly expressed in the brain and HS6ST2 mutations are linked to brain disorders, but the underlying mechanisms remain poorly understood. To determine the role of Hs6st2 in the brain, we carried out a series of molecular and behavioral assessments on Hs6st2 knockout mice. We first carried out strong anion exchange-high performance liquid chromatography and found that knockout of Hs6st2 moderately decreases HS 6-O-sulfation levels in the brain. We then assessed body weights and found that Hs6st2 knockout mice exhibit increased body weight, which is associated with abnormal metabolic pathways. We also performed behavioral tests and found that Hs6st2 knockout mice showed memory deficits, which recapitulate patient clinical symptoms. To determine the molecular mechanisms underlying the memory deficits, we used RNA sequencing to examine transcriptomes in two memory-related brain regions, the hippocampus and cerebral cortex. We found that knockout of Hs6st2 impairs transcriptome in the hippocampus, but only mildly in the cerebral cortex. Furthermore, the transcriptome changes in the hippocampus are enriched in dendrite and synapse pathways. We also found that knockout of Hs6st2 decreases HS levels and impairs dendritic spines in hippocampal CA1 pyramidal neurons. Taken together, our study provides novel molecular and behavioral insights into the role of Hs6st2 in the brain, which facilitates a better understanding of HS6ST2 and HS-linked brain disorders.

Expression and immune infiltration studies of IL-33-ST2-NF-κB signaling pathway in prostate cancer.

BACKGROUND: To analyze the expression of interleukin-33 (IL-33), growth-stimulated expression gene 2 (ST2), nuclear factor-kappaB (NF-κB) and immune cell infiltration in prostate cancer, this study aims to provide an experimental basis for the clinical prevention and treatment of prostate cancer. METHODS: The expression of IL-33 in PCa tissues was analyzed using TCGA, TIMER and HPA databases. Using the UALCAN database, the systematic exploration of the relationship between IL-33 and various clinicopathological parameters was conducted. The correlation between IL-33 expression and immune cell infiltration was investigated using TIMER, CIBERSORT and GEPIA databases. To verify these analyses, 22 cases of normal prostate (NP), 76 cases of benign prostatic hyperplasia (BPH), and 100 cases of PCa were recruited. Immunohistochemical staining was performed to examine the expression of IL-33, ST2, NF-κB, and the infiltration of immune cells. Correlations between these factors were then determined. RESULTS: The expression of IL-33, ST2 and NF-κB was significantly lower in PCa tissues compared with NP (p < 0.05). IL-33 was not associated with age in PCa but showed associations with race, molecular characteristics, lymph node metastatic status, TP53 mutation and tumor grade. Furthermore, IL-33 was associated with immune cell infiltration. Positive correlations were observed between IL-33 and ST2 expressions, as well as between IL-33 and CD68+ macrophages in BPH and PCa. CONCLUSIONS: IL-33, ST2 and NF-κB are lowly expressed in PCa tissues, their expression decreases with the increasing malignancy of cancer. IL-33, ST2 and NF-κB are factors associated with PCa immune infiltration. IL-33 has an inhibitory effect on prostate cancer through the IL-33/ST2/NF-κB signalling pathway.

The immunomodulatory of interleukin-33 in rheumatoid arthritis: A systematic review.

Rheumatoid arthritis (RA) is a systemic chronic autoimmune disease that primarily affects the joints and surrounding soft tissues, characterized by chronic inflammation and proliferation of the synovium. Various immune cells are involved in the pathophysiology of RA. The complex interplay of factors such as chronic inflammation, genetic susceptibility, dysregulation of serum antibody levels, among others, contribute to the complexity of the disease mechanism, disease activity, and treatment of RA. Recently, the cytokine storm leading to increased disease activity in RA has gained significant attention. Interleukin-33 (IL-33), a member of the IL-1 family, plays a crucial role in inflammation and immune regulation. ST2 (suppression of tumorigenicity 2 receptor), the receptor for IL-33, is widely expressed on the surface of various immune cells. When IL-33 binds to its receptor ST2, it activates downstream signaling pathways to exert immunoregulatory effects. In RA, IL-33 regulates the progression of the disease by modulating immune cells such as circulating monocytes, tissue-resident macrophages, synovial fibroblasts, mast cells, dendritic cells, neutrophils, T cells, B cells, endothelial cells, and others. We have summarized and analyzed these findings to elucidate the pathways through which IL-33 regulates RA. Furthermore, IL-33 has been detected in the synovium, serum, and synovial fluid of RA patients. Due to inconsistent research results, we conducted a meta-analysis on the association between serum IL-33, synovial fluid IL-33, and the risk of developing RA in patients. The pooled SMD was 1.29 (95% CI: 1.15-1.44), indicating that IL-33 promotes the onset and pathophysiological progression of RA. Therefore, IL-33 may serve as a biomarker for predicting the risk of developing RA and treatment outcomes. As existing drugs for RA still cannot address drug resistance in some patients, new therapeutic approaches are needed to alleviate the significant burden on RA patients and healthcare systems. In light of this, we analyzed the potential of targeting the IL-33/ST2-related signaling pathway to modulate immune cells associated with RA and alleviate inflammation. We also reviewed IL-33 and RA susceptibility-related single nucleotide polymorphisms, suggesting potential involvement of IL-33 and macrophage-related drug-resistant genes in RA resistance therapy. Our review elucidates the role of IL-33 in the pathophysiology of RA, offering new insights for the treatment of RA.

Activation of interleukin 33-NFκB axis in granulosa cells during atresia and its role in disposal of atretic follicles†.

It has been previously shown that the cytokine interleukin 33 is required for two processes, i.e., autophagic digestion of granulosa cells and recruitment of macrophages into atretic follicles, for full disposal of atretic follicles. Now, this study shows that activation of interleukin 33-suppression of tumorigenicity 2-Nuclear Factor ĸB (NFκB) axis in granulosa in early atretic follicles may regulate those two events. Injection of human chorionic gonadotropin has been shown to induce a transient peak of interleukin 33 expression with synchronized atresia. In this model, interleukin 33-independent expression of suppression of tumorigenicity 2 in granulosa cells was detected in early atretic follicles before macrophage invasion. The activation of NFκB pathway in ovaries was further demonstrated in vivo in Tg mice with luciferase-reporter for NFκB activation; the activation was microscopically localized to granulosa cells in early atretic follicles. Importantly, antibody blockage of interleukin 33 or interleukin 33 Knock-out (KO) (Il33-/-) not only inhibited NFκB activity in ovaries, but it also altered expression of two key genes, i.e., reduction in proinflammatory interleukin6 (IL6) expression, and a surge of potential autophagy-inhibitory mammalian target of rapamycin (mTOR) expression in atretic follicles. By contrast, apoptosis and other genes, such as interleukin1ß (IL1ß) were not affected. In conclusion, in parallel to apoptosis, atresia signals also trigger activation of the interleukin 33-suppression of tumorigenicity 2-NFκB pathway in granulosa, which leads to (1) down-regulated expression of mTOR that is a negative regulator of autophagy and (2) up-regulated expression of proinflammatory IL6.

IL-33/ST2 enhances MMP-12 expression by macrophages to mediate inflammatory and immune response in IgG4-Related Ophthalmic Disease.

IgG4-Related Ophthalmic Disease (IgG4-ROD) is a chronic autoimmune-mediated fibrotic disease that predominantly affects the lacrimal glands, often leading to loss of function in the involved tissues or organs. Recent studies have demonstrated that MMP-12 is highly expressed in IgG4-ROD and plays a significant role in regulating immune responses. In this study, we reviewed nine patients diagnosed with IgG4-ROD based on clinical manifestations and histological analysis, and we investigated the expression of IL-33/ST2 and MMP-12 in IgG4-ROD lacrimal gland tissues using IHC. We found that IL-33 interacts with its specific receptor ST2, both of which are significantly overexpressed in IgG4-ROD tissues. Additionally, we successfully constructed a mouse model by introducing the LatY136F mutation into C57BL/6 mice to mimic IgG4-ROD lacrimal gland involvement, which helped elucidate the mechanisms involved in the induction of MMP-12. Furthermore, immunofluorescence staining confirmed that most MMP-12+ cells were derived from M2 macrophages, and an ELISA assay demonstrated that IL-33 upregulates MMP-12 in IgG4-ROD. Collectively, these data suggest that the IL-33/ST2/MMP-12 signaling pathway is activated in IgG4-ROD, with IL-33/ST2 potentially promoting M2 macrophage polarization and activation to produce MMP-12, which may serve as a novel therapeutic target for IgG4-ROD.

Interleukin-1 family cytokines and soluble receptors in hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a chronic skin disease, characterized by clinical inflammation of the hair follicle with the recurrence of abscesses, nodules, and tunnels. Recently, several studies suggested a role of IL-1 family (IL-1F) cytokines in eliciting and sustaining the disease. The aim of this work is to perform a comprehensive analysis of IL-1F cytokines, soluble inhibitors and receptors in a cohort of HS patients not treated with biological agents. Sixteen patients affected by HS and 16 healthy controls were recruited; clinical data were collected and disease severity evaluated by means of the International HS Severity Score System (IHS4). Serum levels of IL-1F cytokines, inhibitors and receptors were measured using a Multiplex Assays. IL-18 and free IL-18 levels were significantly higher in patients vs controls. Among soluble inhibitors, IL-1Ra, IL-1R2 and ST2/IL-1R4 were significantly increased. IL-18, free IL-18 and IL-33 levels are strongly correlated with IHS4. Also the inhibitors IL-1Ra and IL-18BP show a correlation with IHS4. The data obtained in this study confirm the involvement of IL-1F cytokines in mediating the disease and determining its severity and suggest a possible role for IL-18 as novel serum biomarker of active disease.

Sulfotransferase homolog 2 receptors blockade on monocyte subsets along with their inflammatory cytokines for septic lung injury.

PURPOSE OF THE STUDY: To observe the dynamic changes in monocyte subsets during septic lung injury and to assess the anti-inflammatory role of the sulfotransferase homolog 2 (ST2) receptor. MATERIALS AND METHODS: Dynamic changes of monocyte subsets from patients with septic lung injury and mice post-cecal ligation and puncture (CLP) were monitored. ST2 receptors on mice monocytes and concentrations of IL-33, IL-1ß, IL-12, and IL-27 from peripheral blood or culture supernatant were detected. RESULTS: CD14lowCD16- (Mo0) and CD14++CD16+ (Mo2) monocyte subsets were significantly expanded in patients with sepsis-related acute respiratory distress syndrome. In sepsis model mice, monocyte counts, particularly of Ly6Cint and CDLy6Cint+hi monocytes, were significantly increased. The mean optical density value of TNF-α after CLP mainly increased after 24 h, whereas that of IL-6 was significantly increased at all time points assessed after CLP. The levels of IL-1ß, IL-12, IL-27, and IL-33 increased to variable degrees at 6, 12, 24, and 48h after CLP, and ST2+ monocytes were significantly expanded in sepsis model mice compared to sham-operated mice. ST2 receptor blockade suppressed IL-1ß and IL-12 production in cell culture. CONCLUSIONS: Changes in monocyte subsets expressing the ST2 receptor play an important role in septic lung injury by modulating inflammatory cytokine secretion.

An update of new/potential cardiovascular markers: a narrative review.

BACKGROUND: Cardiovascular and their associated disease (CVD) is a leading cause of death worldwide, in developed and developing countries, and its prevalence has increased over the past few decades, due to changes in the lifestyle of people. Biomarkers are important tools for diagnosing, analyzing, and providing evidence of pathological conditions of CVD and their associated diseases. METHODS: This study reviews historical cardiovascular biomarkers used to diagnose various diseases, their uses, and limitations, as well as the importance of new and emerging biomarkers. CONCLUSION: sST2, GDF-15, CD-40, IL-6, and Micro-RNA. Initial studies of the future of cardiac biomarkers are promising, but more research is needed to demonstrate that they are more effective biomarkers of risk factors for CVD development. They also lack the analytical foundation needed for adoption in the medical industry. It is also necessary to determine whether these biomarkers can be used for diagnosis.

Relationship between serum soluble suppression of tumorigenicity (ST) 2 and global longitudinal strain in early onset preeclampsia.

BACKGROUND: Preeclampsia is one of the leading causes of death in childbearing women worldwide. Hemodynamic changes in preeclampsia can trigger cardiac remodeling as indicated by increase of soluble-ST2 (sST2). Global longitudinal strain were able to detect systolic dysfunction better than the ejection fraction. This study aims to evaluate the correlation between serum levels of sST2 towards GLS in patients with early-onset preeclampsia. METHODS: This is a cross-sectional observational study with correlation analysis. Subjects were patients with severe preeclampsia with gestational age before 34 weeks at Dr. Hasan Sadikin Central General Hospital Bandung and Bandung Kiwari Regional General Hospital from June to August 2022. Examination of sST2 was carried out through blood samples using the ELISA method. sST2 was measured using Presage ST2 Assay reagent. GLS examination was carried out using speckle tracking technique with EchoPAC. Correlation analysis was conducted using the Pearson test if normally distributed, otherwise Spearman's correlation was conducted. Correlation analysis was followed by linear regression. RESULTS: A total of 30 patients met the inclusion criteria. The mean age was 30.83 ± 7.09, with 17 (56.7%) multiparous patients. The median sST2 was 145.75 ng/mL, and the median GLS was - 17.4%. Spearman correlation analysis showed that there was a significant positive correlation with moderate strength between sST2 and GLS (r = 0.583; p < 0.002). Linear regression showed that every 1 ng/ml increase in sST2 would give an increase in GLS of 0.014%. CONCLUSION: There is a significant correlation between sST2 and GLS in patients with early onset severe preeclampsia.

Soluble ST2, BCN-Bio-HF calculator and MAGGIC-HF score in long-term risk prediction after an urgent visit for heart failure.

Soluble ST2 (sST2) is the expression of a pathogenic process related to adverse remodeling that ultimately leads to increased mortality in heart failure (HF). Risk score models provide a comprehensive approach for mortality prediction, beyond the use of biomarkers alone. The objective was to determine the additional value of sST2 and two well-validated contemporary risk scores, BCN-Bio-HF and MAGGIC-HF, in predicting mortality and readmission in the acute setting. This prospective study included 129 patients (mean age 75 ± 9 years; 52% males) after an urgent HF visit. Baseline sST2 levels were measured and the two risk scores were calculated. The primary endpoint was all-cause mortality, and the secondary endpoint was HF readmissions. The follow-up period was 3.6 ± 1.9 years. Patients who died (46%) had higher sST2 concentrations (80.5 vs. 42.7 ng/ml; p < 0.001). The BCN-Bio-HF calculator with sST2 demonstrated the best discriminative ability for mortality prediction (area under the ROC curve: 0.792; p < 0.001). In multivariate analysis for each risk score, the MAGGIC-HF score retained its predictive value only in the model without sST2 (3-year risk: HR = 1.036; 95% CI 1.019-1.054; p < 0.001). However, the BCN-Bio-HF score maintained its prognostic value with sST2 (HR = 1.032; 95%CI 1.020-1.044; p < 0.001), as well as without sST2 (HR = 1.035; 95% CI 1.021-1.049; p < 0.001). sST2 was not associated with readmission, and only the BCN-Bio-HF risk of HF hospitalization showed independent predictive value (OR = 1.040; 95% CI 1.005-1.076; p = 0.023). For predicting long-term mortality in HF in the emergency department, the BCN-Bio-HF calculator with sST2 demonstrated superior discrimination and allows estimation of the risk of HF hospitalizations.

Association of soluble suppression of tumorigenicity 2 with mortality and adverse outcomes in chronic kidney disease: a systematic review and meta-analysis.

BACKGROUND: Early risk stratification is necessary to prevent chronic kidney disease progression and complications. This systematic review aims to evaluate the association of soluble suppression of tumorigenicity 2 (sST2), a member of the interleukin-1 receptor family, with all-cause mortality, cardiovascular disease and renal function deterioration among chronic kidney disease patients. METHODS: PubMed, Scopus, Web of Science, CENTRAL and Google Scholar were systematically searched from inception to December 20, 2023. Cohort studies examining the prognostic role of sST2 levels in pre-dialysis and dialysis patients were included. In case of 3 or more studies per outcome, conventional and dose-response meta-analyses were conducted. RESULTS: Overall, 21 studies were included comprising 15,100 patients. In pre-dialysis patients, the qualitative synthesis of studies suggested that high sST2 is associated with significantly increased all-cause mortality, while evidence regarding cardiovascular events or kidney disease progression was conflicting. In the dialysis population, high sST2 was linked to an elevated risk of all-cause (Hazard ratio-HR: 3.00, 95% confidence intervals-CI: 1.95-4.61) and cardiovascular (HR: 2.38, 95% CI: 1.69-3.34) mortality. Dose-response meta-analysis suggested a log-linear association of sST2 with both all-cause (χ2: 34.65, p value < 0.001) and cardiovascular (χ2: 29.14, p value < 0.001) mortality, whereas findings regarding cardiovascular events were limited with mixed results. CONCLUSIONS: High sST2 values are associated with an increased risk of all-cause mortality in pre-dialysis and dialysis patients, as well as with an elevated risk of cardiovascular mortality in the dialysis population. Further studies are needed to elucidate its potential association with cardiovascular events and kidney disease progression.

Soranus of Ephesus (98-138 ad) and his contributions on human embryology, paediatrics and obstetric knowledge.

This study describes the life and works of Soranus of Ephesus (98-138 AD) who was born in Ephesus in Asia Minor and he practiced medicine in Alexandria and Rome in the Roman period (1st/2nd century AD). Although the majority of his writings have been lost, his surviving popular scientific textbook, a four-volume treatise on "Gynecology", describes ancient medical practice regarding human embryology, paediatrics and obstetrics.

Thymic stromal lymphopoietin rather than IL-33 drives food allergy after epicutaneous sensitization to food allergen.

BACKGROUND: A major route of sensitization to food allergen is through an impaired skin barrier. IL-33 and thymic stromal lymphopoietin (TSLP) have both been implicated in epicutaneous sensitization and food allergy, albeit in different murine models. OBJECTIVE: We assessed the respective contributions of TSLP and IL-33 to the development of atopic dermatitis (AD) and subsequent food allergy in TSLP and IL-33 receptor (ST2)-deficient mice using an AD model that does not require tape stripping. METHOD: TSLP receptor (TSLPR)-/-, ST2-/-, and BALB/cJ control mice were exposed to 3 weekly epicutaneous skin patches of one of saline, ovalbumin (OVA), or a combination of OVA and Aspergillus fumigatus (ASP), followed by repeated intragastric OVA challenges and development of food allergy. RESULTS: ASP and/or OVA patched, but not OVA-alone patched, BALB/cJ mice developed an AD-like skin phenotype. However, epicutaneous OVA sensitization occurred in OVA patched mice and was decreased in ST2-/- mice, resulting in lower intestinal mast cell degranulation and accumulation, as well as OVA-induced diarrhea occurrences on intragastric OVA challenges. In TSLPR-/- mice, intestinal mast cell accumulation was abrogated, and no diarrhea was observed. AD was significantly milder in OVA + ASP patched TSLPR-/- mice compared to wild type and ST2-/- mice. Accordingly, intestinal mast cell accumulation and degranulation were impaired in OVA + ASP patched TSLPR-/- mice compared to wild type and ST2-/- mice, protecting TSLPR-/- mice from developing allergic diarrhea. CONCLUSION: Epicutaneous sensitization to food allergen and development of food allergy can occur without skin inflammation and is partly mediated by TSLP, suggesting that prophylactic targeting of TSLP may be useful in mitigating the development of AD and food allergy early in life in at-risk infants.

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.

The Level of Markers Stimulating Growth Factor 2 (ST2), N-Terminal Prohormone of Brain Natriuretic Peptide (NT-proBNP), and D-Dimer in Healthy Volunteer Testers in 21-Day Head-Down -6° Tilt Bed Rest as a Model of Hypodynamia.

The paper presents an analysis of the proteomic composition in relation to both the risk of thrombosis and changes in the state of cardiomyocytes associated with the risk of cardiac fibrosis and heart failure. We examined 12 practically healthy male volunteers exposed to head-down -6° tilt bed rest (HDBR) for 21 days. The revealed decrease in the level of stimulating growth factor 2 (ST2) on days 10 and 21 relative to the initial values (background; 5 days before HDBR) indicated a decrease in the myocardial load and cardiomyocyte extensibility. The level of N-terminal prohormone of brain natriuretic peptide (NT-proBNP) increased on day 2, decreased on days 10 and 21 of HDBR relative to the background levels, and returned to baseline values after the recovery period (5 days after HDBR). The revealed changes in the level of NT-proBNP reflected the increase in circulating blood volume corresponding to HDBR duration and the role of the gravity component in increasing the functional load on the myocardium. Unchanged blood level of D-dimer at all points of the study indicates that there is no risk of thrombosis under the conditions of this study.

IL-33-ST2 pathway regulates AECII transdifferentiation by targeting alveolar macrophage in a bronchopulmonary dysplasia mouse model.

Evidence points to the indispensable function of alveolar macrophages (AMs) in normal lung development and tissue homeostasis. However, the importance of AMs in bronchopulmonary dysplasia (BPD) has not been elucidated. Here, we identified a significant role of abnormal AM proliferation and polarization in alveolar dysplasia during BPD, which is closely related to the activation of the IL-33-ST2 pathway. Compared with the control BPD group, AMs depletion partially abolished the epithelialmesenchymal transition process of AECII and alleviated pulmonary differentiation arrest. In addition, IL-33 or ST2 knockdown has protective effects against lung injury after hyperoxia, which is associated with reduced AM polarization and proliferation. The protective effect disappeared following reconstitution of AMs in injured IL-33 knockdown mice, and the differentiation of lung epithelium was blocked again. In conclusion, the IL-33-ST2 pathway regulates AECII transdifferentiation by targeting AMs proliferation and polarization in BPD, which shows a novel strategy for manipulating the IL-33-ST2-AMs axis for the diagnosis and intervention of BPD.