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

Pro-inflammatory cytokines in myasthenia gravis: a systematic review and meta-analysis

BACKGROUND

Myasthenia gravis (MG) is an autoimmune neuromuscular disorder impacting muscle endplate components. Pro-inflammatory cytokines, particularly, might play pivotal roles in MG pathogenesis, influencing regulatory T cells and contributing to chronic inflammation. We did this systematic review and meta-analysis to address the conflicting results about pro-inflammatory cytokine profiles in MG.

METHODS

A thorough search was conducted in PubMed, Scopus, and Embase to find studies measuring interleukin (IL)-1 family (IL-1β, IL-18, IL-33, IL-36, IL-37), IL-6, and tumor necrosis factor-alpha (TNF-α) levels in MG patients' serum and controls. Selection criteria encompassed various MG types, including ocular and generalized, with and without thymoma, and acetylcholine receptor (AChR) antibody-positive and negative.

RESULTS

Of the 1843 identified studies, 16 met the inclusion criteria. The meta-analysis revealed a significant increase in serum TNF-α, IL-1β, and IL-33 level in MG patients compared to controls. The included studies also implied elevated levels of IL-18 in people with MG compared to controls and elevated levels of IL-18 and IL-33 in generalized MG compared to ocular MG.

CONCLUSION

Our study highlights the altered profiles of pro-inflammatory cytokines in MG.

Anti-ST2 antibody reduces airway hyperresponsiveness mediated by monocyte-derived macrophages during influenza A infection

Influenza A virus (IAV) infections trigger asthma attacks and cause airway hyperresponsiveness (AHR) in murine models. However, the mechanism by which AHR is induced remains to be fully elucidated. Here, we show that targeting the interleukin (IL)-33 suppression of tumorigenicity 2 (ST2) receptor complex with an anti-ST2 antibody during acute IAV infection of C57BL/6 mice reduced AHR, without affecting expansion of ILC2s and independently of IL-13. Among the lung inflammatory cells, the anti-ST2 antibody selectively reduced the monocyte-derived macrophages (MMs). Furthermore, AHR was reduced in C-C chemokine receptor 2 (CCR2)-knockout mice that have deficient MM recruitment. Depletion of MMs achieved by anti-Ly6C antibody administration also reduced AHR. The treatment of airway smooth muscle (ASM) with conditioned medium from IL-33-treated human THP-1-derived macrophages enhanced potassium chloride-induced ASM contraction. These findings suggest that MMs contribute to acute AHR following IAV infection in an IL-33-dependent manner, but independent of the ILC2/IL-13 axis. Additionally, IL-33 stimulates the release of macrophage-derived mediators that enhance airway smooth muscle contraction, offering a potential mechanistic basis for IAV-induced AHR.

Peripheral protein inflammatory biomarkers in bipolar disorder and major depressive disorder: A systematic review and meta-analysis

OBJECTIVES

Bipolar disorder (BD) and major depressive disorder (MDD) are mood disorders. The most frequent clinical presentation of BD and MDD is depression, which contributes to high rates of misdiagnosis between disorders. To support diagnostic discrimination and therapeutic stratification, we aim to perform a systematic review and meta-analysis evaluating peripheral protein inflammatory biomarkers between BD and MDD, with a focus on the depressive state.

METHODS

We conducted a literature search on PubMed, PsycInfo and Embase with no year/language restrictions. Original studies including human participants with a BD or MDD diagnosis which directly compared levels of peripheral protein inflammatory biomarkers between groups were included. A random effects meta-analysis was performed.

RESULTS

35 studies were included in the systematic review. 9 studies were included in the meta-analysis. The meta-analysis showed IL-7 (p < 0.01) levels were significantly decreased in BD, and IL-9 (p < 0.01), CCL3 (p = 0.03), CCL4 (p = 0.01), CCL5 (p = 0.02) and CCL11 (p = 0.04) levels were significantly increased in BD.

LIMITATIONS

High heterogeneity and limited dataset size restricted our meta-analysis to a small subset of biomarkers and limited our exploration of the effects of moderator variables.

CONCLUSION

This study found differences in IL-7, IL-9, CCL3, CCL4, CCL5 and CCL11 between BD and MDD in a depressive state. These findings support the notion that inflammation is associated with mood disorder pathophysiology, particularly with respect to T-cell network dysregulation. Further studies can assist in better understanding differences between disorders and work towards clinical applications.

Macrophage-mediated activation of the IL4I1/AhR axis is a key player in allergic rhinitis

BACKGROUND

Epidemiological evidence suggests that environmental pollutants precipitate the occurrence of allergic rhinitis (AR). The aryl hydrocarbon receptor (AhR), a receptor or sensor for various contaminants, is closely related to immunomodulation and the polarization of M2 macrophages. However, the mechanisms involving AhR and M2 macrophages in AR remain unclear.

METHODS

Bioinformatics analysis of GEO datasets (GSE180697 and GSE180697) assessed AhR and IL4I1 expression levels, which were then verified in the nasal mucosa, monocytes and serum of patients with AR using western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). Primary human mononuclear cells were isolated from peripheral blood using a magnetic separation technique, and THP-1 cell lines with IL4I1 overexpression or downexpression were established through lentiviral constructs. M2 macrophages were induced with the cytokines CSF, IL4 and IL13 and then treated with the AhR agonist FICZ or inhibitor CH223191. The polarization of M2 macrophages was measured by flow cytometry and western blotting. Furthermore, primary nasal epithelial cells and macrophages were co-cultured to assess the epithelial-mesenchymal transition (EMT) in epithelial cells. The AR murine model was established using ovalbumin (OVA). Inflammation within the nasal mucosa and lung tissue was examined after CH223191 or IL4I1 treatment.

RESULTS

Nuclear translocation of AhR and upregulation of IL4I1 was observed in peripheral mononuclear cells and nasal mucosal tissue of patients with AR. Through the activation of AhR, IL4I1 promoted M2 macrophage polarization. Furthermore, modulation of the IL4I1/AhR axis regulated the migratory impact of OVA on T-M2 cells. The IL4I1/AhR axis was involved in the regulation of M2 macrophage-associated EMT and contributed to the expression of IL-33 and STAT6 phosphorylation in epithelial cells. In AR mice, increased AhR nuclear translocation and higher expression of IL4I1 and the M2 macrophage marker CD206 in the lungs was observed. The IL4I1/AhR axis exacerbated allergic symptoms in AR mice, fostering allergic inflammation within the nasal mucosa and lungs.

CONCLUSIONS

The IL4I1/AhR axis is activated within the mononuclear phagocyte system of patients with AR. This activation facilitates the polarization of mononuclear cells into M2 macrophages, which further aggravates EMT in epithelial cells and exacerbates inflammation in AR. This study may provide novel strategies for the precise treatment of AR.

Associations of Soluble Serum Stimulation-2 With Functional Outcomes and Death at 1 Year in Acute Ischemic Stroke: A Prospective Cohort Study

BACKGROUND

Elevated sST2 (soluble serum stimulation-2) has been associated with poor 90-day outcomes of patients with acute ischemic stroke (AIS). We aimed to investigate the associations between baseline serum sST2 level and 1-year outcomes in patients with AIS.

METHODS AND RESULTS

This was a prospective, observational, cohort study, enrolling patients with AIS with sST2 levels measured using serum samples obtained within 24 hours of onset. The primary outcome was 1-year functional dependence (modified Rankin Scale score 3-5) or all-cause death. Secondary outcomes included 1-year functional dependence, all-cause death, and modified Rankin Scale score distribution, analyzed separately. Logistic regression, shift analyses of the modified Rankin Scale score, and restricted cubic splines were used to examine the association of sST2 level with 1-year outcomes. Among 312 patients (median age 61 years, 28.5% women), 37 (11.9%) had a primary outcome (27 with functional dependence, 10 all-cause deaths). Serum sST2 level >24.6 ng/mL was independently associated with the primary outcome and secondary outcomes. Higher continuous sST2 level was significantly associated with the primary outcome and functional dependence, and tended to be associated with 1-year all-cause death and higher modified Rankin Scale score. Multivariable-adjusted restricted cubic splines showed a linear relationship between higher sST2 level and 1-year risk of primary outcome, functional dependence, or all-cause death. In subgroup analyses, higher serum sST2 level was more significantly associated with the primary outcome in those with than without prior AIS beyond 1 year before the index AIS and coronary artery disease.

CONCLUSIONS

Higher serum sST2 level within 24 hours of onset could be a promising predictor of 1-year worse functional outcomes and death after AIS.

Relationships between schizophrenia and the alarmins interleukin-33 (IL-33), soluble receptor of interleukin-33 (sST2) and the ratio IL-33/sST2. A systematic review

Schizophrenia is a multi-aetiologic disease. Inflammation have recently been involved in its pathophysiology. Recent research suggests that inflammation may be a key factor in its pathophysiology. Alarmins, interleukin-33 (IL-33), its soluble receptor sST2 and the ratio IL-33/sST2, have been investigated as neuroinflammation biomarkers. However, data on alarmins in schizophrenia remain scarce and conflicting, with findings varying across studies. The aim of this systematic review consists of analysing the relationships between IL-33, its sST2 and the ratio IL-33/sST2 in schizophrenia. The authors follow the PRISMA recommendations. The keywords IL-33 OR interleukin-33 OR sST2 OR soluble ST2 OR IL-33/sST2 were intersected with the Boolean operator AND with the key words schizophrenia OR psychosis OR psychotic disorder. The search was carried out in PubMed/MEDLINE, EMBASE, PsycInfo, Scopus and Web of Science. Despite the initial search yielding 115 publications, only five studies met inclusion criteria, comprising 107 healthy controls (HC) and 267 patients, highlighting the limited data available. IL-33 and its sST2 were significantly increased in patients with an acute relapse compared to HC, while patients in clinical remission had levels comparable to those of HC. No consistent relationship was found between antipsychotic treatment and IL-33 or sST2 levels, raising questions about the influence of medication on these markers. The quality of evidence was low to moderate (10 ± 1, with an evidence level of 3 ± 0, according to the Oxford Centre for Evidence-Based Medicine criteria). This systematic review highlights the possibility that IL-33 and sST2 play a role in the pathophysiology of schizophrenia, particularly in relation to neuroinflammation and neuronal dysfunction. However, the controversial and inconsistent findings suggest the need for larger, well-controlled studies. Additionally, the lack of mechanistic insight into how these alarmins contribute to schizophrenia pathophysiology remains a critical gap. Understanding the impact of IL-33 and sST2 on neuroinflammatory pathways could provide new therapeutic targets. Future research should also explore whether these markers can aid in early diagnosis or monitoring treatment response.

Keloids and inflammation: the crucial role of IL-33 in epidermal changes

Introduction

Keloids are benign fibroproliferative disorders characterized by excessive collagen deposition and inflammation that extend beyond the original wound boundaries. IL-33 is an alarmin cytokine released upon cellular damage or stress. Dysregulation of IL-33 in epidermal keratinocytes compromises the skin barrier and triggers chronic inflammation.

Method

In this study, we first noticed an increased expression of IL-33 in the keratinocytes of keloid epidermis through histological staining. Then, an increased expression of IL-33 receptor (ST2) in the lymphocytes infiltrating the superficial dermis of keloid scars were identified through histological staining and flow cytometry analysis. The IFN-γ-IL-33 loop between lymphocytes and keratinocytes were further revealed by flow cytometry and Western blotting analysis. The abnormal keratinocyte differentiation in epiderm is mediated by IFN-γ-IL-33 loop were confirmed by in vitro studies in HaCaT cells via Western blotting analysis and immunofluorescence staining. Finally, the IFN-γ-IL-33 loop were also verified in cocultured peripheral blood mononuclear cells and HaCaT through ELISA analysis.

Results

Our results demonstrate that IL-33 levels are significantly elevated in the epidermis of keloid tissues, where it functions as an alarmin, promoting a chronic inflammatory response. We further reveal a feedback loop between IL-33 and interferon-gamma (IFN-γ), whereby IL-33 induces IFN-g production in lymphocytes, which in turn stimulates keratinocytes to produce more IL-33. This loop contributes to impaired keratinocyte differentiation and skin barrier dysfunction, exacerbating the inflammatory environment.

Discussion

By elucidating the role of the IL-33/ST2 axis in keloid formation, this research provides valuable insights into potential therapeutic targets for managing this challenging condition.

The dual role of tissue regulatory T cells in tissue repair: return to homeostasis or fibrosis

Tissue resident regulatory T cells (tissue Tregs) are vital for maintaining immune homeostasis and controlling inflammation. They aid in repairing damaged tissues and influencing the progression of fibrosis. However, despite extensive research on how tissue Tregs interact with immune and non-immune cells during tissue repair, their pro- and anti-fibrotic effects in chronic tissue injury remain unclear. Understanding how tissue Tregs interact with various cell types, as well as their roles in chronic injury and fibrosis, is crucial for uncovering the mechanisms behind these conditions. In this review, we describe the roles of tissue Tregs in repair and fibrosis across different tissues and explore potential strategies for regulating tissue homeostasis. These insights hold promise for providing new perspectives and approaches for the treatment of irreversible fibrotic diseases.

Elevated Soluble Suppressor of Tumorigenicity 2 Levels in Gout Patients and Its Association with Cardiovascular Disease Risk Indicators

PURPOSE

To investigate the association between soluble suppressor of tumorigenicity 2 (sST2) levels and cardiovascular disease predictors in patients with gout.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of patients with gout who were tested for sST2 but did not receive uric acid-lowering therapy. These patients were classified into elevated and normal sST2 groups using a cut-off of >49.6 ng/mL and >35.4 ng/mL in males and females, respectively. Correlations between clinical and laboratory variables, sST2 levels, and elevated sST2 level predictors were assessed using linear and logistic regression analyses.

RESULTS

Notably, 27 (11.3%) and 211 (88.7%) of the 238 identified patients had elevated and normal sST2 levels, respectively. Linear regression analysis revealed that male sex (β=-0.190, p=0.002), body mass index (BMI) (β=-0.184, p=0.002), white blood cell count (β=0.231, p<0.001), C-reactive protein (β=0.135, p=0.031), and fasting blood glucose (β=0.210, p<0.001) were independently associated with sST2 levels. In multivariate logistic regression analysis, male sex [odds ratio (OR) 0.112, p=0.001], BMI (OR 0.836, p=0.008), creatinine (OR 5.730, p=0.024), and fasting blood glucose (OR 1.042, p=0.002) predicted elevated sST2 levels. Patients with increased sST2 levels had a significantly higher atherosclerotic cardiovascular disease risk score and a greater proportion of high-risk Framingham Risk Score compared to the normal sST2 group (p=0.002 and p<0.001).

CONCLUSION

Patients with gout and elevated sST2 levels have a higher risk of future cardiovascular disorders, which may provide insights into risk stratification and the implementation of intervention strategies.

Exploring the shared genetic mechanisms of atopic dermatitis and alopecia areata via bioinformatics approaches

Atopic dermatitis (AD) and alopecia areata (AA) are chronic inflammatory skin diseases. While studies suggest a possible immune defense mechanism link between the two, the causal relationship remains unclear, and current methodologies have limitations. This study aims to investigate the causal relationship between AD and AA using genome-wide association study statistics from the Integrative Epidemiology Unit Open Genome-Wide Association Study (IEU Open Gwas) project. We utilized the inverse variance weighting (IVW) method as our primary analysis approach for assessing the causal association between AD and AA. To enhance the robustness of our findings, we also employed supplementary validation methods, including the weighted median, MR-Egger method, and other analytical approaches. Our analysis revealed a significant increase in the risk of AA associated with single-nucleotide polymorphisms (SNPs) linked to AD (odds ratio (OR) = 1.84, 95% confidence interval (CI): 1.19-2.85, p-value (p) = 0.006). While MR-Egger analysis did not show a significant association (OR = 1.04, 95% CI: 0.29-3.68, p = 0.957), weighted median analysis demonstrated a significant association (OR = 2.08, 95% CI: 1.16-3.71, p = 0.013). Additionally, MR-Egger intercept and MR-PRESSO analysis showed no evidence of potential pleiotropy or horizontal pleiotropy between AD and AA. This study indicates that AD increases the risk of AA, providing valuable insights into the pathogenesis and prevention of these two diseases. Future research should explore the underlying mechanisms to better understand this relationship.

Coagulopathy prediction in traumatic brain injury

Traumatic brain injury (TBI) represents a significant public health concern. Besides the initial primary injury, a defining point of TBI is causing secondary, delayed damage through inflammatory biochemical processes. Among the complications arising from this inflammatory response, coagulopathy emerges as a critical concern. With an overall prevalence of 32.7 %, TBI-induced coagulopathy significantly contributes to increased mortality rates and unfavorable patient outcomes, through its clinical manifestations, such as progressive hemorrhagic injury (PHI). This chapter investigates biomarkers capable of accurately detecting coagulopathy and PHI in TBI, evaluating their potential utility based on statistical evidence from various studies and exploring their possible association in the biochemical processes guiding or following TBI-induced coagulopathy. Notably, glucose emerges as a standout candidate, exhibiting a sensitivity of 91.5 % and specificity of 87.5 % for predicting coagulopathy. Furthermore, interleukin-33, with a sensitivity of 93.3 % and specificity of 66.7 %, and galectin-3, with a sensitivity of 67.7 % and specificity of 85.5 %, are promising for PHI. Despite these encouraging findings, significant efforts remain necessary to translate biomarker diagnostic utility into clinical practice effectively. Further research and validation studies are imperative to elucidate the intricate biochemical processes underlying TBI-induced coagulopathy and to refine the clinical application of biomarkers for improved patient management and outcomes in real-world settings.

Single cell transcriptome profiling reveals pathogenesis of bullous pemphigoid

Bullous pemphigoid (BP) triggers profound functional changes in both immune and non-immune cells in the skin and circulation, though the underlying mechanisms remain unclear. In this study, we conduct single-cell transcriptome analysis of lesional and non-lesional skin, as well as blood samples from BP patients. In lesional skin, non-immune cells upregulate pathways related to metabolism, wound healing, immune activation, and cell migration. LAMP3+DCs from cDC2 show stronger pro-inflammatory signatures than those from cDC1, and VEGFA+ mast cells, crucial for BP progression, are predominantly in lesional skin. As BP patients transition from active to remission stages, blood B cell function shifts from differentiation and memory formation to increased type 1 interferon signaling and reduced IL-4 response. Blood CX3CR1+ ZNF683+ and LAG3+ exhausted T cells exhibit the highest TCR expansion among clones shared with skin CD8+T cells, suggesting their role in fueling skin CD8+T cell clonal expansion. Clinical BP severity correlates positively with blood NK cell IFN-γ production and negatively with amphiregulin (AREG) production. NK cell-derived AREG mitigates IFN-γ-induced keratinocyte apoptosis, suggesting a crucial balance between AREG and IFN-γ in BP progression. These findings highlight functional shifts in BP pathology and suggest potential therapeutic targets.

Dynamics of Immune Cell Infiltration and Fibroblast-Derived IL-33/ST2 Axis Induction in a Mouse Model of Post-Surgical Lymphedema

Lymphedema is an intractable disease most commonly associated with lymph node dissection for cancer treatment and can lead to a decreased quality of life. Type 2 T helper (Th2) lymphocytes have been shown to be important in the progression of lymphedema. The activation of IL-33 and its receptor, the suppression of tumorigenicity 2 (ST2) signaling pathway, induces the differentiation of Th2 cells, but its involvement in lymphedema remains unclear. In the present study, we analyzed the dynamics of immune cell infiltration, including the IL-33/ST2 axis, in a mouse tail lymphedema model. Neutrophil infiltration was first detected in the lymphedema tissue on postoperative day (POD) 2. Macrophage infiltration increased from POD 2 to 5. The number of CD4+ T cells, including 50% Tregs, gradually increased from POD 14. The mRNA expression of ll13 and Ifng increased on POD 21. The expression of IL-33 was induced in fibroblast nuclei within dermal and subcutaneous tissues from POD 2, and the expression of the Il1rl1 gene encoding ST2 increased from POD 7. We demonstrated the infiltration process from innate to acquired immune cells through the development of a mouse tail lymphedema. The IL-33/ST2 axis was found to be induced during the transition from innate to acquired immunity.

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.

Soluble suppression of tumorigenicity 2 associated with contrast-induced acute kidney injury in patients with STEMI

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is a common complication after percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). Soluble suppression of tumorigenicity 2 (sST2) is associated with AKI. However, the relationship between sST2 and CI-AKI is unclear. This study aimed to investigate the relationship between sST2 and CI-AKI in patients with STEMI.

METHODS

This was a single-center retrospective observational study. Patients diagnosed with STEMI in the Yichun People's Hospital from February 2020 to May 2024 were continuously included. CI-AKI was defined as an increase in serum creatinine of at least 50% or 0.3 mg/dL from baseline within 48-72 h after contrast exposure.

RESULTS

The incidence of CI-AKI after PCI was 12.4% (98/791). Univariate analysis showed that age, fasting plasma glucose, diabetes mellitus, Killip class, left ventricular ejection fraction, estimated glomerular filtration rate, high sensitivity troponin T, N-terminal pro-B-type natriuretic peptide, and sST2 were associated with CI-AKI. The above factors were included in a multivariate analysis, which showed that sST2 was an independent factor for CI-AKI after PCI. The restricted cubic splines showed a nonlinear dose-response relationship between sST2 and CI-AKI (P < 0.001). The integration of the sST2 could significantly improve the ability of the model to identify CI-AKI (NRI 0.681, 95% CI 0.474-0.887; IDI 0.063, 95% CI 0.038-0.099).

CONCLUSION

Elevated sST2 is an independent risk factor for CI-AKI after PCI in patients with STEMI. Integration of sST2 can significantly improve the risk model for CI-AKI.

Cross-sectional study of proteomic differences between moderate and severe psoriasis

Although an ongoing understanding of psoriasis vulgaris (PV) pathogenesis, little is known about the proteomic differences between moderate and severe psoriasis. In this cross-sectional study, we evaluated the proteomic differences between moderate and severe psoriasis using data-independent acquisition mass spectrometry (DIA-MS). 173 differentially expressed proteins (DEPs) were significantly differentially expressed between the two groups. Among them, 85 proteins were upregulated, while 88 were downregulated (FC ≥ ± 1.5, P < 0.05). Eighteen DEPs were mainly enriched in the IL - 17 signalling pathway, Neutrophil extracellular trap formation, Neutrophil degranulation and NF - kappa B signalling pathway, which were associated with psoriasis pathogenesis. Ingenuity pathway Analysis (IPA) identified TNF and TDP53 as the top upstream up-regulators, while Lipopolysaccharide and YAP1 were the top potential down-regulators. The main active pathways were antimicrobial peptides and PTEN signalling, while the inhibitory pathways were the neutrophil extracellular trap pathway, neutrophil degranulation, and IL-8 signalling. 4D-parallel reaction monitoring (4D-PRM) suggested that KRT6A were downregulated in severe psoriasis. Our data identify Eighteen DEPs as biomarkers of disease severity, and are associated with IL - 17 signalling pathway, Neutrophil extracellular trap formation, NF - kappa B signalling pathway, and defence response to the bacterium. Targeting these molecules and measures to manage infection may improve psoriasis's severity and therapeutic efficacy.

Immunophenotyping of T Cells in Lung Malignancies and Cryptogenic Organizing Pneumonia

Background: Lung malignancies, including cancerous lymphangitis and lymphomas, can mimic interstitial lung diseases like cryptogenic organizing pneumonia (COP) on imaging, leading to diagnostic delays. We aimed to identify potential biomarkers to distinguish between these conditions. Methods: We analyzed bronchoalveolar lavage fluid from 8 patients (4 COP, mean age 59.8 ± 13.5 years; 4 lung malignancies including 2 cancerous lymphangitis, 1 MALT lymphoma, and 1 diffuse large B cell lymphoma, mean age 67.8 ± 4.5 years) using mass cytometry with 35 T cell markers. Data were analyzed using principal component analysis (PCA) and unsupervised Citrus clustering. Results: PCA of T cell marker intensities effectively separated the two groups, with IL-2Rα, PD-L2, CD45RA, CD44, and OX40 being the top discriminating markers. Citrus analysis showed a significant increase in the CD16+ CD4+ and CD16+ CD8+ T cell populations in the COP group compared to lung malignancies. Conclusions: Our findings reveal distinct T cell immunophenotypes in COP versus lung malignancies, particularly increased CD16+ T cells in COP, which could serve as potential diagnostic biomarkers.

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.

ST2 + T-Regulatory Cells in Renal Inflammation and Fibrosis after Ischemic Kidney Injury

Key Points

IL-33/ST2 alarmin pathway regulates inflammation, fibrosis, and resolution of ischemia-reperfusion injury of kidneys. ST2 regulates the transcriptome of T-regulatory cells related to suppressive and reparative functions. The secretome of ST2+ T-regulatory cells regulates hypoxic injury in an amphiregulin-dependent manner.

Background

Inflammation is a major cause of kidney injury. IL-1 family cytokine IL-33 is released from damaged cells and modulates the immune response through its receptor ST2 expressed on many cell types, including regulatory T cells (Tregs). Although a proinflammatory role of IL-33 has been proposed, exogenous IL-33 expanded Tregs and suppressed renal inflammation. However, the contribution of endogenous IL-33/ST2 for the role of Tregs in the resolution of kidney injury has not been investigated.

Methods

We used murine renal ischemia-reperfusion injury and kidney organoids (KDOs) to delineate the role of the ST2 and amphiregulin (AREG) specifically in Tregs using targeted deletion. Bulk and single-cell RNA sequencing were performed on flow-sorted Tregs from spleen and CD4 T cells from postischemic kidneys, respectively. The protective role of ST2-sufficient Tregs was analyzed using a novel coculture system of syngeneic KDOs and Tregs under hypoxic conditions.

Results

Bulk RNA sequencing of splenic and single-cell RNA sequencing of kidney CD4 T cells showed that ST2+ Tregs are enriched for genes related to Treg proliferation and function. Genes for reparative factors, such as Areg , were also enriched in ST2+ Tregs. Treg-specific deletion of ST2 or AREG exacerbated kidney injury and fibrosis in the unilateral ischemia-reperfusion injury model. In coculture studies, wild-type but not ST2-deficient Tregs preserved hypoxia-induced loss of kidney organoid viability, which was restored by AREG supplementation.

Conclusions

Our study identified the role of the IL-33/ST2 pathway in Tregs for resolution of kidney injury. The transcriptome of ST2+ Tregs was enriched for reparative factors including Areg . Lack of ST2 or AREG in Tregs worsened kidney injury. Tregs protected KDOs from hypoxia in a ST2- and AREG-dependent manner.

How maternal factors shape the immune system of breastfed infants to alleviate food allergy: A systematic and updated review

What infants eat early in life may shape the immune system and have long-standing consequences on the health of the host during later life. In the early months post-birth, breast milk serves as the exclusive and optimal nourishment for infants, facilitating crucial molecular exchanges between mother and infant. Recent advances have uncovered that some maternal factors influence breastfed infant outcomes, including the risk of food allergy (FA). To date, accumulated data show that breastfed infants have a lower risk of FA. However, the issue remains disputed, some reported preventive allergy effects, while others did not confirm such effects, or if identified, protective effects were limited to early childhood. The disputed outcomes may be attributed to the maternal status, as it determines the compounds of the breast milk that breastfed infants are exposed to. In this review, we first detail the compounds in breast milk and their roles in infant FA. Then, we present maternal factors resulting in alterations in breast milk compounds, such as maternal health status, maternal diet intake, and maternal food allergen intake, which subsequently impact FA in breastfed infants. Finally, we analyze how these compounds in breast milk alleviated the infant FA by mother-to-infant transmission. Altogether, the mechanisms are primarily linked to the synergetic and direct effects of compounds in breast milk, via promoting the colonization of gut microbiota and the development of the immune system in infants.

Dynamics of tissue repair regulatory T cells and damage in acute Trypanosoma cruzi infection

Tissue-repair regulatory T cells (trTregs) comprise a specialized cell subset essential for tissue homeostasis and repair. While well-studied in sterile injury models, their role in infection-induced tissue damage and antimicrobial immunity is less understood. We investigated trTreg dynamics during acute Trypanosoma cruzi infection, marked by extensive tissue damage and strong CD8+ immunity. Unlike sterile injury models, trTregs significantly declined in secondary lymphoid organs and non-lymphoid target tissues during infection, correlating with systemic and local tissue damage, and downregulation of function-associated genes in skeletal muscle. This decline was linked to decreased systemic IL-33 levels, a key trTreg growth factor, and promoted by the Th1 cytokine IFN-γ. Early recombinant IL-33 treatment increased trTregs, type 2 innate lymphoid cells, and parasite-specific CD8+ cells at specific time points after infection, leading to reduced tissue damage, lower parasite burden, and improved disease outcome. Our findings not only provide novel insights into trTregs during infection but also highlight the potential of optimizing immune balance by modulating trTreg responses to promote tissue repair while maintaining effective pathogen control during infection-induced injury.

Personalized Medicine in Chronic Rhinosinusitis: Treatable Traits Using Biologics for Unmet Needs

Chronic rhinosinusitis (CRS) is a prevalent airway disease, leading to health, social, and economic burdens, and substantially impairs quality of life. As CRS is heterogeneous and contains diverse pathogenesis, treatment outcomes and prognosis vary from curative to intractable. Inflammatory endotypes of CRS are divided into 3 types-type 1, type 2 and type 3-based on cytokines promoted. Tissue/blood eosinophilia seems to be the most reliable and feasible biomarker for type 2 CRS in clinical settings, although the cutoff level of eosinophilia remains to be elucidated. In East Asia, the predominant pathogenesis has changed from neutrophilic type 3 inflammation to eosinophilic type 2 inflammation over the past decades. The treatment strategy for CRS has also evolved from classical phenotype-based "reliever-controller" treatment to endotype-based "treatable traits" treatment. "Treatable traits" treatment is a personalized approach for the management of airway disease with complex and heterogeneous conditions. In CRS, traits can be grouped into sinonasal, extra-nasal and risk factor/behavioral domains. Type 2 CRS is one of the sinonasal traits, and biologics targeting immunoglobulin E, interleukin (IL)-5 and its receptor, IL-4/IL-13 receptor (IL-4/IL-13R) and thymic stromal lymphopoietin are the corresponding treatments for this trait. Proper use of these biologics can achieve high efficacy with patient satisfaction, leading to clinical remission. However, some cases show marked hypereosinophilia after the reduction or discontinuation of systemic corticosteroid or the switching of biologics from anti-IL-5/IL-5R to anti-IL-4Rα monoclonal antibody. More precise research on CRS targeting endotype, genotype, regiotype and theratype is needed to address the unmet needs and refine the "treatable traits" treatment of CRS.

Alarmins and their pivotal role in the pathogenesis of spontaneous abortion: insights for therapeutic intervention

Alarmins are a class of molecules released when affected cells damaged or undergo apoptosis. They contain various chemotactic and immunomodulatory proteins or peptides. These molecules regulate the immune response by interacting with pattern recognition receptors (PRRs) and play important roles in inflammatory response, tissue repair, infection defense, and cancer treatment. Spontaneous abortion (SA) is a common pregnancy-related disease, and its pathogenesis has been puzzling clinicians, so it needs to be further studied. In this paper, we first reviewed the research status of various alarmins and SA, focusing on the role of high mobility box 1 (HMGB1), interleukin33 (IL-33), interleukin1β (IL-1β) and S-100 protein (S100 protein) in immune response, inflammation, embryonic development and abortion. Subsequently, this paper summarized the effect of alarmins on pregnancy outcome by influencing angiogenesis-related factors. Finally, from the perspective of aseptic inflammation, the pro-inflammatory signaling pathways involved in various alarmins and their targeted drugs were reviewed. By focusing on specific molecules in alarmins and their receptors and signaling pathways, we can more accurately conduct drug research and development. The purpose of this review is to explore the role of alarmins in SA, and provide important references for early detection of abortion risk, revealing the disease mechanism, developing new therapies and improving the prognosis of patients.

Multimodal Screening for Pulmonary Arterial Hypertension in Systemic Scleroderma: Current Methods and Future Directions

Systemic sclerosis (SSc) is an immuno-inflammatory rheumatic disease that can affect both the skin and internal organs through fibrosis. Pulmonary arterial hypertension (PAH) is one of the most severe secondary complications. Structural changes in the vascular bed lead to increased pressures in the pulmonary circulation, severely impacting the right heart and significantly affecting mortality. The gold standard for diagnosing PAH is right heart catheterization (RHC), an invasive method for measuring cardiac pressure. Due to the high risk of complications, procedural difficulties, and significant costs, non-invasive screening for SSc-PAH has garnered significant interest. Echocardiography is likely the most important screening tool, providing structural and functional information about the right heart through measurements that have proven their utility over time. In addition to imagistic investigations, serum biomarkers aid in identifying patients at risk for PAH and can provide prognostic information. Currently, well-known serum biomarkers (NT-proBNP, uric acid) are used in screening; however, in recent years, researchers have highlighted new biomarkers that can enhance diagnostic accuracy for SSc patients. Pulmonary involvement can also be assessed through pulmonary function tests, which, using established thresholds, can provide additional information and help select patients requiring RHC. In conclusion, given the invasiveness of RHC, non-invasive screening methods are particularly important for SSc patients.

Key Interleukins in Inflammatory Bowel Disease-A Review of Recent Studies

Inflammatory bowel disease (IBD) is an immune disorder of the gastrointestinal tract with a complex aetiopathogenesis, whose development is influenced by many factors. The prevalence of IBD is increasing worldwide, in both industrialized and developing countries, making IBD a global health problem that seriously affects quality of life. In 2019, there were approximately 4.9 million cases of IBD worldwide. Such a large number of patients entails significant healthcare costs. In the treatment of patients with IBD, the current therapeutic target is mucosal healing, as intestinal inflammation often persists despite resolution of abdominal symptoms. Treatment strategies include amino salicylates, corticosteroids, immunosuppressants, and biologic therapies that focus on reducing intestinal mucosal inflammation, inducing and prolonging disease remission, and treating complications. The American College of Gastroenterology (ACG) guidelines also indicate that nutritional therapies may be considered in addition to other therapies. However, current therapeutic approaches are not fully effective and are associated with various limitations, such as drug resistance, variable efficacy, and side effects. As the chronic inflammation that accompanies IBD is characterized by infiltration of a variety of immune cells and increased expression of a number of pro-inflammatory cytokines, including IL-6, TNF-α, IL-12, IL-23 and IFN-γ, new therapeutic approaches are mainly targeting immune pathways. Interleukins are one of the molecular targets in IBD therapy. Interleukins and related cytokines serve as a means of communication for innate and adaptive immune cells, as well as nonimmune cells and tissues. These cytokines play an important role in the pathogenesis and course of IBD, making them promising targets for current and future therapies. In our work, we review scientific studies published between January 2022 and November 2024 describing the most important interleukins involved in the pathogenesis of IBD. Some of the papers present new data on the precise role that individual interleukins play in IBD. New clinical data have also been provided, particularly on blocking interleukin 23 and interleukin 1beta. In addition, several new approaches to the use of different interleukins in the treatment of IBD have been described in recent years.

A Combined Extract from Dioscorea bulbifera and Zingiber officinale Mitigates PM2.5-Induced Respiratory Damage by NF-κB/TGF-β1 Pathway

This research evaluated the protective role of a combined extract of Dioscorea bulbifera and Zingiber officinale (DBZO) against respiratory dysfunction caused by particulate matter (PM2.5) exposure in BALB/c mice. The bioactive compounds identified in the DBZO are catechin, astragalin, 6-gingerol, 8-gingerol, and 6-shogaol. DBZO ameliorated cell viability and reactive oxygen species (ROS) production in PM2.5-stimulated A549 and RPMI 2650 cells. In addition, it significantly alleviated respiratory dysfunction in BALB/c mice exposed to PM2.5. DBZO improved the antioxidant systems in lung tissues by modulating malondialdehyde (MDA) content, as well as levels of reduced glutathione (GSH) and superoxide dismutase (SOD). Likewise, DBZO restored mitochondrial dysfunction by improving ROS levels, mitochondrial membrane potential, and ATP production. Moreover, DBZO modulated the levels of neutrophils, eosinophils, monocytes, and lymphocytes (specifically CD4+, CD8+, and CD4+IL-4+ T cells) in blood and IgE levels in serum. DBZO was shown to regulate the c-Jun N-terminal kinase (JNK) pathway, nuclear factor kappa B (NF-κB) pathway, and transforming growth factor β (TGF-β)/suppressor of mothers against decapentaplegic (Smad) pathway. Histopathological observation indicated that DBZO mitigates the increase in alveolar septal thickness. These findings indicate that DBZO is a promising natural agent for improving respiratory health.

IL-33 and soluble ST2 in follicular fluid are associated with premature ovarian insufficiency

Background

Premature ovarian insufficiency (POI) is a common reproductive disease that is associated with chronic inflammation in ovaries. Interleukin 33 (IL-33) is a pro-inflammatory IL-1 family cytokine, and functions as an alarmin reflecting inflammatory reaction. Our study aimed to investigate levels of IL-33 and its soluble receptor (sST2) in both follicular fluid (FF) and paired serum during different stages of POI, and evaluate their predictive potentials for POI. Furthermore, we attempted to determine whether IL-33 and sST2 were associated with embryo quality.

Methods

A total of 148 women, including 50 patients with biochemical POI (bPOI) (10 IU/L < follicle-stimulating hormone (FSH) ≤ 25 IU/L), 46 patients with POI (25 IU/L

Results

FF IL-33 levels were significantly increased in bPOI and POI patients compared to controls. They exhibited positive associations with FSH and luteinizing hormone (LH), whereas negative correlations with anti-Müllerian hormone (AMH), estradiol (E2), testosterone (T) and antral follicle count (AFC). Receiver operating characteristic (ROC) curve analysis showed that for POI prediction, FF IL-33 had a better predictive accuracy (AUC 0.901) with high sensitivity (82.61%) and good specificity (84.62%) than those for bPOI prediction. IL-33 levels in paired serum did not differ among three groups. Regarding sST2, its levels in FF declined with POI progression. Contrarily, they showed negative associations with FSH and LH, but positive correlations with AMH, E2, T and AFC. ROC analysis revealed that FF sST2 had comparatively weak potentials for both bPOI and POI prediction compared to those of FF IL-33. Similarly, there was no significant alteration of sST2 in paired serum among three groups. Additionally, Spearman's correlation analysis revealed that FF IL-33 levels were negatively associated with the rates of Day-3 good-quality embryos (r=-0.206, P=0.012), whereas FF sST2 did not.

Conclusion

Our study revealed an increased abundance of FF IL-33, whereas an sST2 deficiency with POI development. This implies that IL-33 and sST2 levels might be associated with the development of POI.

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Key Words

• IL-33
• embryo development
• embryo quality
• inflammation
• ovarian reserve
• predictor
• premature ovarian insufficiency
• soluble ST2

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MESH Headings

• Humans
• Female
• Interleukin-33/blood
• Interleukin-33/metabolism
• Interleukin-1 Receptor-Like 1 Protein/blood
• Interleukin-1 Receptor-Like 1 Protein/metabolism
• Follicular Fluid/metabolism
• Primary Ovarian Insufficiency/blood
• Primary Ovarian Insufficiency/metabolism
• Adult
• Biomarkers/blood
• Biomarkers/metabolism
• Biomarkers/analysis
• Follicle Stimulating Hormone/blood
• Follicle Stimulating Hormone/metabolism
• Case-Control Studies

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Affiliation(s)

Maoxing Tang Department of Reproductive Medicine, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
Xuedong Sun Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
Ping Li Department of Reproductive Medicine, Women and Children’s Hospital, School of Medicine, Xiamen University, Xiamen, China
Weifen Deng Reproductive Medicine Centre, Shenzhen Hengsheng Hospital, Shenzhen, China
Xi Zhan Department of Reproductive Medicine, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
Peng Sun Department of Reproductive Medicine, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
Yuhua Shi Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China

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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.

Interleukin-33 and Obesity-Related Inflammation and Cancer

Interleukin-33 (IL-33) is a cytokine belonging to the IL-1 family. It is primarily associated with type 2 immune responses. It interacts with a receptor complex on immune cells in reaction to tissue damage or cellular injury. IL-33 is crucial in immune responses and is involved in various autoimmune and inflammatory diseases. Obesity is marked by chronic inflammation and is a known risk factor for several types of cancer. Recent studies have shown that IL-33 and its receptor complex are expressed in adipose (fat) tissue, suggesting they may play a role in obesity. While inflammation connects obesity and cancer, it is not yet clear whether IL-33 contributes to cancer associated with obesity. Depending on the cellular context, inflammatory environment, expression levels, and bioactivity, IL-33 can exhibit both protumorigenic and antitumorigenic effects. This review will explore the various functions of IL-33 in the inflammation linked to obesity and its relationship with cancer.

Dysregulation of T cell response in the pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD), comprised of Crohn's disease (CD) and ulcerative colitis (UC), are gut inflammatory diseases that were earlier prevalent in the Western Hemisphere but now are on the rise in the East, with India standing second highest in the incidence rate in the world. Inflammation in IBD is a cause of dysregulated immune response, wherein helper T (Th) cell subsets and their cytokines play a major role in the pathogenesis of IBD. In addition, gut microbiota, environmental factors such as dietary factors and host genetics influence the outcome and severity of IBD. Dysregulation between effector and regulatory T cells drives gut inflammation, as effector T cells like Th1, Th17 and Th9 subsets Th cell lineages were found to be increased in IBD patients. In this review, we attempted to discuss the role of different Th cell subsets together with other T cells like CD8+ T cells, NKT and γδT cells in the outcome of gut inflammation in IBD. We also highlighted the potential therapeutic candidates for IBD.

IL-33 in cancer immunotherapy: Pleiotropic functions and biological strategies

Interleukin-33 (IL-33) belongs to the IL-1 cytokine superfamily and plays a critical role in regulating immune responses and maintaining host homeostasis. IL-33 is essential for driving and enhancing type 2 immune responses and is closely associated with the pathogenesis of various inflammatory diseases, infections, and the progression and metastasis of cancers. This study aimed to provide an overview of the anti-tumor effects of IL-33 by examining its complex immunomodulatory functions within the tumor microenvironment and how it regulates immune cells to mediate these effects. We also provided perspectives on the pleiotropic roles of IL-33 in immunomodulation, its potential use in cancer immunotherapies, and possible adverse effects associated with its therapeutic application. Understanding these mechanisms is crucial for developing more effective IL-33-based diagnostic and therapeutic strategies.

The diagnostic and prognostic value of soluble ST2 in Sepsis

Objective

To determine the diagnostic and prognostic value of soluble suppression of tumorigenicity 2 (sST2) in patients with sepsis.

Methods

A total of 113 critically ill patients were enrolled at the emergency department of Beijing Chaoyang Hospital Jing Xi Branch. Venous blood levels of sST2 were measured using the AFIAS-6 dry fluorescence immunoassay analyzer. Based on Sepsis 3.0 criteria, patients were categorized into a sepsis group (76 cases) and a non-sepsis group (37 cases). The sepsis group was further divided into non-survivors (38 cases) and survivors (38 cases) based on 28-day survival outcomes. The vital signs, blood gas analysis, routine blood tests, liver and kidney function tests, procalcitonin (PCT), C-reactive protein (CRP), sST2, left ventricular ejection fraction (LVEF), and other basic characteristics of the patients were recorded. Further, the SOFA, qSOFA and APACHE II scores of each patient were calculated. Statistical analysis was performed using SPSS 25.0, including logistic regression and ROC curve analysis to assess prognostic factors.

Results

The serum sST2 levels in the sepsis group (125.00 ± 60.32 ng/mL) were significantly higher than in the non-sepsis group (58.55 ± 39.03 ng/mL) (p < 0.05). The SOFA score (8.08 ± 2.88), APACHE II score (18.00 ± 4.72), blood sST2 levels (168.06 ± 36.75 ng/mL) and lactic acid levels (2.89 ± 3.28) in the non-survivor group were significantly higher than the survivor group (p < 0.05). Multiple logistic regression analysis showed that sST2, SOFA score, APACHE II score and lactic acid levels were independent risk factors for poor prognosis in patients with sepsis. The ROC curve analysis of the above indexes showed no significant differences between the AUC of sST2 (0.912) and the SOFA score (0.929) (z = 0.389, p = 0.697), or the APACHE II score (0.933) (z = 0.484, p = 0.627). However, there was a significant difference between the AUC of sST2 (0.912) and lactic acid levels (0.768) (z = 2.153, p = 0.030).

Conclusion

Blood levels of sST2 show a clinically diagnostic and prognostic value in sepsis. Further, sST2 shows a similar predictive ability as the SOFA and APACHE II scores in determining the prognosis of sepsis patients. However, sST2 has a higher predictive ability than lactic acid levels in determining prognosis in sepsis.

Studies of Structure-Activity Relationship of 2-(Pyrrolidin-1ylmethyl)-1H-pyrrole-Based ST2 Inhibitors and Their Inhibition of Mast Cells Activation

ST2 belongs to the interleukin 1 receptor family and is expressed in immune cells including certain CD4+ T cells and mast cells. Binding of ST2 with interleukin 33 (IL-33) induces downstream signaling that activates NF-κB pathway. Although the ST2/IL-33 axis exerts immune tolerance via expansion of regulator T cells, the same axis also activates a subset of immune cells to produce proinflammatory cytokines in host defense or in tissue repair. Here, we reported the development of ST2 inhibitors with improved inhibitory activities against ST2 and metabolic stability based on a previous lead, iST2-14e. Using the human mast cell line (LAD2), we showed that ST2 inhibitors mitigated ST2 upregulation and reduced IL-1β released through degranulation, demonstrating that small-molecule ST2 inhibitors effectively attenuated the ST2/IL-33 signaling in human mast cells. Further optimization of the compounds may lay the foundation for developing ST2 inhibitors for the treatment of mast cells mediated diseases.

The IL-33/ST2 Axis Affects Adipogenesis Through Regulating the TRAF6/RelA Pathway

Understanding the regulatory mechanisms of adipogenesis is essential for preventing obesity. Interleukin-33 (IL-33) has recently attracted increasing attention for its role in adipogenesis. The purpose of this study was to explore the function and regulatory mechanism of IL-33 and its receptor suppression of tumorigenicity 2 (ST2) on adipogenesis. Here, Oil Red O staining was used to detect the accumulation of intracellular lipid droplets. Molecular techniques such as qRT-PCR and Western blotting were used to detect the expression of pivotal genes and adipogenic marker genes. Gains and losses of function experiments were used to explore the potential regulatory mechanism of the IL-33/ST2 axis in adipogenesis. Functionally, IL-33 is negatively associated with adipogenesis in 3T3-L1 preadipocytes, while ST2 is positively associated with it, encompassing both the trans-membrane receptor ST2 (ST2L) and the soluble ST2 (sST2). Mechanistically, the IL-33/ST2 axis affects adipogenesis by regulating the expression of the TRAF6/RelA pathway in 3T3-L1 preadipocytes. Downregulating the expression of ST2 suppressed the activation of the IL-33/ST2 axis, which subsequently inhibits the expression of TRAF6. This further attenuates the expression of RelA, ultimately resulting in the suppression of adipogenesis in 3T3-L1 preadipocytes. This study reveals a new mechanism by which the IL-33/ST2 axis regulates the differentiation of preadipocytes and provides a new idea for improving obesity prevention.

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.

Epidermal growth factor receptor/mitogen-activated kinase inhibitor treatment induces a distinct inflammatory hair follicle response that includes collapse of immune privilege

BACKGROUND

Inhibitors of epidermal growth factor receptor (EGFRi) or mitogen-activated kinase (MEKi) induce a folliculitis in 75-90% of patients, the pathobiology of which remains insufficiently understood.

OBJECTIVES

To characterize changes in the skin immune status and global transcriptional profile of patients treated with EGFRi; to investigate whether EGFRi affects the hair follicle's (HF) immune privilege (IP); and to identify early proinflammatory signals induced by EGFRi/MEKi in human scalp HFs ex vivo.

METHODS

Scalp biopsies were taken from patients exhibiting folliculitis treated long term with EGFRi ('chronic EGFRi' group, n = 9) vs. healthy scalp skin (n = 9) and patients prior to commencing EGFRi treatment and after 2 weeks of EGFRi therapy ('acute EGFRi' group, n = 5). Healthy organ-cultured scalp HFs were exposed to an EGFRi (erlotinib, n = 5) or a MEKi (cobimetinib, n = 5). Samples were assessed by quantitative immunohistomorphometry, RNA sequencing (RNAseq) and in situ hybridization.

RESULTS

The 'chronic EGFRi' group showed CD8+ T-cell infiltration of the bulge alongside a partial collapse of the HF's IP, evidenced by upregulated major histocompatibility complex (MHC) class I, β2-microglobulin (B2 M) and MHC class II, and decreased transforming growth factor-β1 protein expression. Healthy HFs treated with EGFRi/MEKi ex vivo also showed partial HF IP collapse and increased transcription of human leucocyte antigen (HLA)-A, HLA-DR and B2 M transcripts. RNAseq analysis showed increased transcription of chemokines (CXCL1, CXCL13, CCL18, CCL3, CCL7) and interleukin (IL)-26 in biopsies from the 'chronic EGFRi' cohort, as well as increased IL-33 and decreased IL-37 expression in HF biopsies from the 'acute EGFRi' group and in organ-cultured HFs.

CONCLUSIONS

The data show that EGFRi/MEKi compromise the physiological IP of human scalp HFs and suggest that future clinical management of EGFRi/MEKi-induced folliculitis requires HF IP protection and inhibition of IL-33.

Administration of rIL-33 Restores Altered mDC/pDC Ratio, MDSC Frequency, and Th-17/Treg Ratio during Experimental Cerebral Malaria

The onset of malaria causes the induction of various inflammatory markers in the host's body, which in turn affect the body's homeostasis and create several cerebral complications. Polarization of myeloid-derived suppressor cells (MDSCs) from the classically activated M1 to alternatively activated M2 phenotype increases the secretion of pro-inflammatory molecules. Treatment with recombinant IL-33 (rIL-33) not only alters this MDSC's polarization but also targets the glycolysis pathway of the metabolism in MDSCs, rendering them less immunosuppressive. Along with that, the Helper T-cells subset 17 (Th17)/T regulatory cells (Tregs) ratio is skewed towards Th17, which increases inflammation by producing more IL-17. However, treating with rIL-33 also helps to restore this ratio, which brings back homeostasis. During malaria infection, there is an upregulation of IL-12 production from dendritic cells along with a distorted myeloid dendritic cells (mDC)/plasmacytoid dendritic cells (pDC) ratio towards mDCs promoting inflammation. Administering rIL-33 will also subvert this IL-12 production and increase the population of pDC in the host's immune system during malaria infection, thus restoring mDC/pDC to homeostasis. Therefore, treatment with rIL-33 to reduce the pro-inflammatory signatures and maintenance of immune homeostasis along with the increase in survivability could be a potential therapeutic approach for cerebral malaria.

Coronavirus envelope protein activates TMED10-mediated unconventional secretion of inflammatory factors

The precise cellular mechanisms underlying heightened proinflammatory cytokine production during coronavirus infection remain incompletely understood. Here we identify the envelope (E) protein in severe coronaviruses (SARS-CoV-2, SARS, or MERS) as a potent inducer of interleukin-1 release, intensifying lung inflammation through the activation of TMED10-mediated unconventional protein secretion (UcPS). In contrast, the E protein of mild coronaviruses (229E, HKU1, or OC43) demonstrates a less pronounced effect. The E protein of severe coronaviruses contains an SS/DS motif, which is not present in milder strains and facilitates interaction with TMED10. This interaction enhances TMED10-oligomerization, facilitating UcPS cargo translocation into the ER-Golgi intermediate compartment (ERGIC)-a pivotal step in interleukin-1 UcPS. Progesterone analogues were identified as compounds inhibiting E-enhanced release of proinflammatory factors and lung inflammation in a Mouse Hepatitis Virus (MHV) infection model. These findings elucidate a molecular mechanism driving coronavirus-induced hyperinflammation, proposing the E-TMED10 interaction as a potential therapeutic target to counteract the adverse effects of coronavirus-induced inflammation.

RNA sequencing reveals molecular mechanisms of endometriosis lesion development in mice

Understanding of molecular mechanisms contributing to the pathophysiology of endometriosis, and upstream drivers of lesion formation, remains limited. Using a C57Bl/6 mouse model in which decidualized endometrial tissue is injected subcutaneously in the abdomen of recipient mice, we generated a comprehensive profile of gene expression in decidualized endometrial tissue (n=4), and in endometriosis-like lesions at Day 7 (n=4) and Day 14 (n=4) of formation. High-throughput mRNA sequencing allowed identification of genes and pathways involved in the initiation and progression of endometriosis-like lesions. We observed distinct patterns of gene expression with substantial differences between the lesions and the decidualized endometrium that remained stable across the two lesion timepoints, and showed similarity to transcriptional changes implicated in human endometriosis lesion formation. Pathway enrichment analysis revealed several immune and inflammatory response-associated canonical pathways, multiple potential upstream regulators, and involvement of genes not previously implicated in endometriosis pathogenesis, including IRF2BP2 and ZBTB10, suggesting novel roles in disease progression. Collectively, the provided data will be a useful resource to inform research on the molecular mechanisms contributing to endometriosis-like lesion development in this mouse model.

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.

Toward Unveiling Putative Binding Sites of Interleukin-33: Insights from Mixed-Solvent Molecular Dynamics Simulations of the Interleukin-1 Family

The interleukin (IL)-1 family is a major proinflammatory cytokine family, ranging from the well-studied IL-1s to the most recently discovered IL-33. As a new focus, IL-33 has attracted extensive research for its crucial immunoregulatory roles, leading to the development of notable monoclonal antibodies as clinical candidates. Efforts to develop small molecules disrupting IL-33/ST2 interaction remain highly desired but encounter challenges due to the shallow and featureless interfaces. The information from relative cytokines has shown that traditional binding site identification methods still struggle in mapping cryptic sites, necessitating dynamic approaches to uncover druggable pockets on IL-33. Here, we employed mixed-solvent molecular dynamics (MixMD) simulations with diverse-property probes to map the hotspots of IL-33 and identify potential binding sites. The protocol was first validated using the known binding sites of two IL-1 family members and then applied to the structure of IL-33. Our simulations revealed several binding sites and proposed side-chain rearrangements essential for the binding of a known inhibitor, aligning well with experimental NMR findings. Further microsecond-time scale simulations of this IL-33-protein complex unveiled distinct binding modes with varying occurrences. These results could facilitate future efforts in developing ligands to target challenging flexible pockets of IL-33 and IL-1 family cytokines in general.

Biomarkers to predict and diagnose pulmonary complications in children post haematopoietic stem cell transplant

OBJECTIVES

Haematopoietic cell transplant (HCT) is a cellular therapy for a group of high-risk children with cancer, immunodeficiency and metabolic disorders. Whilst curative for a child's underlying condition, HCT has significant risks associated, including lung injury. These complications are associated with increased post HCT mortality and require improved methods of risk stratification, diagnosis and treatment.

METHODS

Biomarkers measured in bronchoalveolar fluid and peripheral blood have been identified for both acute and chronic lung injury post HCT.This review evaluates the current research available investigating the use of these biomarkers to improve clinical care, with a focus on the paediatric cohort.

RESULTS

Elevated levels of cytokines such as IL-6, IL-8, G-CSF and TNF were identified as potential predictive biomarkers for the development of post HCT lung disease. The pulmonary microbiome was found to have strong potential as a biomarker pre and post HCT for the development of pulmonary complications. General limitations of the studies identified were study design, retrospective or single centre and not exclusively performed in the paediatric population.

CONCLUSION

To translate biomarker discovery into clinical implementation further research is required, utilising larger cohorts of children in prospective trials to validate these biomarkers and determine how they can be translated into better outcomes for children post HCT.

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.

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.

Blocking IL-33 decelerates cartilage degeneration in knee osteoarthritis through mice model

INTRODUCTION

Osteoarthritis (OA) is a chronic inflammatory disease where pro-inflammatory cytokines, damage-associated molecular patterns and macrophages play a crucial role. However, the interaction of these mediators, the exact cause, and the treatment of knee osteoarthritis (KOA) are still unclear. Moreover, the interaction of interleukin (IL)-33, platelet-derived growth factor-BB (PDGF-BB), and matrix metalloproteinase-9 (MMP-9) with other factors in the pathogenesis of KOA has not been elaborately explored.

METHOD

Therefore, in this study, we analyzed the expression of IL-33, PDGF-BB, and MMP-9 in the knee cartilage tissue of model mice, murine KOA was induced by using the destabilization of the medial meniscus (DMM) model.

RESULTS

Compared with the sham operation control group, the expression levels of PDGF-BB, IL-33, and MMP-9 were increased significantly, and the pathological sections showed obvious cartilage damage. Additionally, we assessed the levels of IL-33 and MMP-9 expression in the knee joint of KOA model mice following intervention with PDGF-BB antibody, and we found that the expression level of MMP-9 was reduced following intervention with IL-33 antibody. When the effects of the three antibodies were compared in a mouse disease model, it was discovered that the IL-33 antibody could dramatically lower the relative expression level of MMP-9, resulting in the least amount of cartilage damage and improved protection. In conclusion, inhibiting IL-33 can significantly lower inflammatory factor levels in the knee joint, including IL-33 and MMP-9, and it can improve cartilage breakdown in osteoarthritis of the knee.

CONCLUSION

Overall, the results indicate that IL-33 has a therapeutic function in the treatment of knee osteoarthritis and may be a novel target for treatment of the underlying causes of KOA. Additionally, PDGF-BB might be an upstream pathway of IL-33, and KOA's MMP-9 is an downstream pathway of IL-33.

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.

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.