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

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

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

Introduction: The alarmin IL-33 has been implicated in the pathology of immune-mediated liver diseases. IL-33 activates regulatory T cells (Tregs) and type 2 innate lymphoid cells (ILC2s) expressing the IL-33 receptor ST2. We have previously shown that endogenous IL-33/ST2 signaling activates ILC2s that aggravate liver injury in murine immune-mediated hepatitis. However, treatment of mice with exogenous IL-33 before induction of hepatitis ameliorated disease severity. Since IL-33 induces expression of amphiregulin (AREG) crucial for Treg function, we investigated the immunoregulatory role of the ST2+ Treg/AREG axis in immune-mediated hepatitis. Methods: C57BL/6, ST2-deficient (Il1rl1-/-) and Areg-/- mice received concanavalin A to induce immune-mediated hepatitis. Foxp3Cre+ x ST2fl/fl mice were pre-treated with IL-33 before induction of immune-mediated hepatitis. Treg function was assessed by adoptive transfer experiments and suppression assays. The effects of AREG and IL-33 on ST2+ Tregs and ILC2s were investigated in vitro. Immune cell phenotype was analyzed by flow cytometry. Results and discussion: We identified IL-33-responsive ST2+ Tregs as an effector Treg subset in the murine liver, which was highly activated in immune-mediated hepatitis. Lack of endogenous IL-33 signaling in Il1rl1-/- mice aggravated disease pathology. This was associated with reduced Treg activation. Adoptive transfer of exogenous IL-33-activated ST2+ Tregs before induction of hepatitis suppressed inflammatory T-cell responses and ameliorated disease pathology. We further showed increased expression of AREG by hepatic ST2+ Tregs and ILC2s in immune-mediated hepatitis. Areg-/- mice developed more severe liver injury, which was associated with enhanced ILC2 activation and less ST2+ Tregs in the inflamed liver. Exogenous AREG suppressed ILC2 cytokine expression and enhanced ST2+ Treg activation in vitro. In addition, Tregs from Areg-/- mice were impaired in their capacity to suppress CD4+ T-cell activation in vitro. Moreover, application of exogenous IL-33 before disease induction did not protect Foxp3Cre+ x ST2fl/fl mice lacking ST2+ Tregs from immune-mediated hepatitis. In summary, we describe an immunoregulatory role of the ST2+ Treg/AREG axis in immune-mediated hepatitis, in which AREG suppresses the activation of hepatic ILC2s while maintaining ST2+ Tregs and reinforcing their immunosuppressive capacity in liver inflammation.

IL-33-ST2 signaling in fibro-adipogenic progenitors alleviates immobilization-induced muscle atrophy in mice.

BACKGROUND: The regenerative and adaptive capacity of skeletal muscles reduces with age, leading to severe disability and frailty in the elderly. Therefore, development of effective therapeutic interventions for muscle wasting is important both medically and socioeconomically. In the present study, we aimed to elucidate the potential contribution of fibro-adipogenic progenitors (FAPs), which are mesenchymal stem cells in skeletal muscles, to immobilization-induced muscle atrophy. METHODS: Young (2-3 months), adult (12-14 months), and aged (20-22 months) mice were used for analysis. Muscle atrophy was induced by immobilizing the hind limbs with a steel wire. FAPs were isolated from the hind limbs on days 0, 3, and 14 after immobilization for transcriptome analysis. The expression of ST2 and IL-33 in FAPs was evaluated by flow cytometry and immunostaining, respectively. To examine the role of IL-33-ST2 signaling in vivo, we intraperitoneally administered recombinant IL-33 or soluble ST2 (sST2) twice a week throughout the 2-week immobilization period. After 2-week immobilization, the tibialis anterior muscles were harvested and the cross-sectional area of muscle fibers was evaluated. RESULTS: The number of FAPs increased with the progression of muscle atrophy after immobilization in all age-groups. Transcriptome analysis of FAPs collected before and after immobilization revealed that Il33 and Il1rl1 transcripts, which encode the IL-33 receptor ST2, were transiently induced in young mice and, to a lesser extent, in aged mice. The number of FAPs positive for ST2 increased after immobilization in young mice. The number of ST2-positive FAPs also increased after immobilization in aged mice, but the difference from the baseline was not statistically significant. Immunostaining for IL-33 in the muscle sections revealed a significant increase in the number of FAPs expressing IL-33 after immobilization. Administration of recombinant IL-33 suppressed immobilization-induced muscle atrophy in aged mice but not in young mice. CONCLUSIONS: Our data reveal a previously unknown protective role of IL-33-ST2 signaling against immobilization-induced muscle atrophy in FAPs and suggest that IL-33-ST2 signaling is a potential new therapeutic target for alleviating disuse muscle atrophy, particularly in older adults.

Mutation landscape in Chinese nodal diffuse large B-cell lymphoma by targeted next generation sequencing and their relationship with clinicopathological characteristics.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL), an aggressive and heterogenic malignant entity, is still a challenging clinical problem, since around one-third of patients are not cured with primary treatment. Next-generation sequencing (NGS) technologies have revealed common genetic mutations in DLBCL. We devised an NGS multi-gene panel to discover genetic features of Chinese nodal DLBCL patients and provide reference information for panel-based NGS detection in clinical laboratories. METHODS: A panel of 116 DLBCL genes was designed based on the literature and related databases. We analyzed 96 Chinese nodal DLBCL biopsy specimens through targeted sequencing. RESULTS: The most frequently mutated genes were KMT2D (30%), PIM1 (26%), SOCS1 (24%), MYD88 (21%), BTG1 (20%), HIST1H1E (18%), CD79B (18%), SPEN (17%), and KMT2C (16%). SPEN (17%) and DDX3X (6%) mutations were highly prevalent in our study than in Western studies. Thirty-three patients (34%) were assigned as genetic classification by the LymphGen algorithm, including 12 cases MCD, five BN2, seven EZB, seven ST2, and two EZB/ST2 complex. MYD88 L265P mutation, TP53 and BCL2 pathogenic mutations were unfavorable prognostic biomarkers in DLBCL. CONCLUSIONS: This study presents the mutation landscape in Chinese nodal DLBCL, highlights the genetic heterogeneity of DLBCL and shows the role of panel-based NGS to prediction of prognosis and potential molecular targeted therapy in DLBCL. More precise genetic classification needs further investigations.

Epidemiology, resistance genomics and susceptibility of Acinetobacter species: results from the 2020 Spanish nationwide surveillance study.

BackgroundAs increasing antibiotic resistance in Acinetobacter baumannii poses a global healthcare challenge, understanding its evolution is crucial for effective control strategies.AimWe aimed to evaluate the epidemiology, antimicrobial susceptibility and main resistance mechanisms of Acinetobacter spp. in Spain in 2020, and to explore temporal trends of A. baumannii.MethodsWe collected 199 single-patient Acinetobacter spp. clinical isolates in 2020 from 18 Spanish tertiary hospitals. Minimum inhibitory concentrations (MICs) for nine antimicrobials were determined. Short-read sequencing was performed for all isolates, and targeted long-read sequencing for A. baumannii. Resistance mechanisms, phylogenetics and clonality were assessed. Findings on resistance rates and infection types were compared with data from 2000 and 2010.ResultsCefiderocol and colistin exhibited the highest activity against A. baumannii, although colistin susceptibility has significantly declined over 2 decades. A. non-baumannii strains were highly susceptible to most tested antibiotics. Of the A. baumannii isolates, 47.5% (56/118) were multidrug-resistant (MDR). Phylogeny and clonal relationship analysis of A. baumannii revealed five prevalent international clones, notably IC2 (ST2, n = 52; ST745, n = 4) and IC1 (ST1, n = 14), and some episodes of clonal dissemination. Genes bla OXA-23, bla OXA-58 and bla OXA-24/40 were identified in 49 (41.5%), eight (6.8%) and one (0.8%) A. baumannii isolates, respectively. ISAba1 was found upstream of the gene (a bla OXA-51-like) in 10 isolates.ConclusionsThe emergence of OXA-23-producing ST1 and ST2, the predominant MDR lineages, shows a pivotal shift in carbapenem-resistant A. baumannii (CRAB) epidemiology in Spain. Coupled with increased colistin resistance, these changes underscore notable alterations in regional antimicrobial resistance dynamics.

Molecular prevalence and subtype distribution of Blastocystis spp. among children who have diarrheia or are asymptomatic in Wenzhou, Zhejiang Province, China.

Blastocystis sp., a significant zoonotic parasite with a global distribution, was the focus of this study, which aimed to investigate its prevalence and genetic diversity among diarrheic and asymptomatic children in Wenzhou, China. We collected 1,032 fecal samples from Yuying Children's Hospital, Wenzhou, China, comprising 684 from children with diarrhea and 348 from asymptomatic children. Genomic DNA extracted from these samples was used to detect Blastocystis spp. by PCR, targeting the small subunit ribosomal RNA gene. Subsequently, a phylogenetic tree was constructed, applying the maximum likelihood method. Blastocystis spp. were detected in 67 (6.5%) of the fecal samples. The prevalence rate of Blastocystis spp. in diarrheic children (8.8%; 60/684) was significantly higher than that in asymptomatic children (2.0%; 7/348) (χ 2 = 17.3, p < 0.001). Sequence analysis of the SSU rRNA gene identified five known Blastocystis spp. subtypes, ST1 (n = 12), ST2 (n = 5), ST3 (n = 35), ST4 (n = 12), and ST7 (n = 3). ST1 and ST3 were present in both diarrheic and asymptomatic children, while ST2, ST4, and ST7 were exclusive to diarrheic children. Intra-subtype genetic polymorphisms were identified, comprising four variations in ST1 (ST1-1 to ST1-4), five in ST3 (ST3-1 to ST3-5), two in ST4 (ST4-1 and ST4-2), and two in ST7 (ST7-1 and ST7-2). Notably, ST1-2 to ST1-4, ST3-3 to ST3-5, and ST7-1 and ST7-2 represent newly identified variations. The composition and genetic characteristics of subtypes among children in this region suggest various sources of infection, including human-to-human and animal-to-human transmission.

Title: Prévalence moléculaire et distribution des sous-types de Blastocystis spp. parmi les enfants diarrhéiques et asymptomatiques à Wenzhou, Province du Zhejiang, Chine. Abstract: Blastocystis sp., un parasite zoonotique important avec une distribution mondiale, était au centre de cette étude, qui visait à étudier sa prévalence et sa diversité génétique parmi les enfants diarrhéiques et asymptomatiques de Wenzhou, en Chine. Nous avons collecté 1 032 échantillons fécaux à l'hôpital pour enfants Yuying de Wenzhou, en Chine, dont 684 provenant d'enfants souffrant de diarrhée et 348 d'enfants asymptomatiques. L'ADN génomique extrait de ces échantillons a été utilisé pour détecter Blastocystis sp. par PCR, ciblant le gène de la petite sous-unité de l'ARN ribosomal. Par la suite, un arbre phylogénétique a été construit, en appliquant la méthode du maximum de vraisemblance. Blastocystis sp. a été détecté dans 67 (6,5 %) des échantillons fécaux. Le taux de prévalence de Blastocystis spp. chez les enfants diarrhéiques (8,8 % ; 60 / 684) était significativement plus élevé que chez les enfants asymptomatiques (2,0 % ; 7 / 348) (χ2 = 17,3, p < 0,001). L'analyse de la séquence du gène de l'ARNr SSU a identifié cinq sous-types de Blastocystis spp., ST1 (n = 12), ST2 (n = 5), ST3 (n = 35), ST4 (n = 12) et ST7 (n = 3). Les sous-types ST1 et ST3 étaient présents chez les enfants diarrhéiques et asymptomatiques, tandis que ST2, ST4 et ST7 étaient exclusifs aux enfants diarrhéiques. Des polymorphismes génétiques intra-sous-types ont été identifiés, comprenant quatre variations dans ST1 (ST1-1 à ST1-4), cinq dans ST3 (ST3-1 à ST3-5), deux dans ST4 (ST4-1 et ST4-2) et deux dans ST7 (ST7-1 et ST7-2). Notamment, ST1-2 à ST1-4, ST3-3 à ST3-5, ST7-1 et ST7-2 représentent des variations nouvellement identifiées. La composition et les caractéristiques génétiques des sous-types chez les enfants de cette région suggèrent diverses sources d'infection, notamment la transmission interhumaine et animale.

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

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

Dietary Salicornia ramosissima improves the European seabass (Dicentrarchus labrax) inflammatory response against Photobacterium damselae piscicida.

Introduction: Modern fish farming faces challenges in sourcing feed ingredients, most related with their prices, 21 availability, and specifically for plant protein sources, competition for the limited cultivation space for 22 vegetable crops. In that sense, halophytes have the added value of being rich in valuable bioactive compounds and salt tolerant. This study assessed the inclusion of non-food fractions of S. ramosissima in European seabass diets. Methods: Different levels (2.5%, 5%, and 10%) were incorporated into seabass diets, replacing wheat meal (diets ST2.5, ST5, and ST10) or without inclusion (CTRL). Experimental diets were administered to seabass juveniles (8.62 ± 0.63 g) for 34 and 62 days and subsequent inflammatory responses to a heat-inactivated Photobacterium damselae subsp. piscicida (Phdp) were evaluated in a time-course manner (4, 24, 48, and 72 h after the challenge). At each sampling point, seabass haematological profile, plasma immune parameters, and head-kidney immune-related gene expression were evaluated. Results: After both feeding periods, most parameters remained unaltered by S. ramosissima inclusion; nonetheless, seabass fed ST10 showed an upregulation of macrophage colony-stimulating factor 1 receptor 1 (mcsf1r1) and cluster of differentiation 8 (cd8ß) compared with those fed CTRL after 62 days of feeding. Regarding the inflammatory response, seabass fed ST10 showed lower plasma lysozyme levels than their counterparts fed ST2.5 and ST5 at 24 h following injection, while 4 h after the inflammatory stimulus, seabass fed ST10 presented higher numbers of peritoneal leucocytes than fish fed CTRL. Moreover, at 4 h, fish fed ST2.5, ST5, and ST10 showed a higher expression of interleukin 1ß (il1ß), while fish fed ST5 showed higher levels of ornithine decarboxylase (odc) than those fed CTRL. An upregulation of macrophage colony-stimulating factor 1 receptor 1 (mcsf1r1) and glutathione peroxidase (gpx) was also observed at 72 h in fish fed ST10 or ST5 and ST10 compared with CTRL, respectively. Discussion: In conclusion, incorporating up to 10% of the non-food fraction S. ramosissima in feed did not compromise seabass growth or immune status after 62 days, aligning with circular economy principles. However, S. ramosissima inclusion improved the leucocyte response and upregulated key immune-related genes in seabass challenged with an inactivated pathogen.

Combination of IL-33 with PD-1 blockade augment mILC2s-mediated anti-tumor immunity.

BACKGROUND: Group 2 innate lymphoid cells (ILC2s) represent one of the main tissue-specific innate lymphoid cell populations, which are key drivers of cytokine secretion in their occupational niche. However, the precise involvement of ILC2s in cancer immunity and their potential impact on immunotherapeutic approaches remain poorly understood. METHODS: The proportion of ILC2s originating from various tissue sources were quantified through flow cytometry, along with the determination of CD4+ T cell and CD8+ T cell percentages. Flow cytometry was also employed to assess IFN-γ production and programmed cell death protein-1 (PD-1) expression in T cells. Immunohistochemistry was utilized to detect IL-33 expression in tumor tissues, while immunofluorescence was employed to confirm the infiltration of ILC2s in both murine and human tumor tissues. RESULTS: In this study, we provide evidence that intra-tumoral ILC2s in lung adenocarcinoma (LUAD) exist in a quiescent state. However, the activation of intra-tumoral ILC2s is induced by IL-33 specifically in a natural ILC2s (nILC2, ST2+KLRG1-) phenotype. Considering the pivotal role of PD-1 in cancer immunotherapy and its immunoregulatory functions, we investigated the synergistic effects of IL-33 and anti-PD-1 and found that their combination enhances anti-tumor immunity and improves the efficacy of immunotherapy. Moreover, this combination leads to the upregulation of activated mature ILC2s (mILC2, ST2+KLRG1+) phenotype, thereby highlighting the activated ILC2s as a novel enhancer of the immunoregulatory properties of anti-PD-1. CONCLUSIONS: Collectively, these findings underscore the significance of ILC2s and their contribution to the anti-tumor response in the context of cancer immunotherapy. Consequently, the simultaneous targeting of ILC2s and T cells represents a potentially promising and widely applicable strategy for immunotherapeutic interventions.

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

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

Celecoxib attenuates interleukin 33-induced expression of vascular cell adhesion molecule-1 in human ovarian endometriotic stromal cells.

OBJECTIVE: Endometriosis is an estrogen-dependent chronic inflammatory disease in women of reproductive age. A review of the literature revealed that cytokines and inflammatory factors are associated with endometriosis-associated infertility. Interleukin 33 (IL-33) is a strong inducer of other pro-inflammatory cytokines. Vascular cell adhesion molecule-1 (VCAM-1) plays a central role in recruiting inflammatory cells, whose expression facilitates leukocyte adhesion and is rapidly induced by pro-inflammatory cytokines. Many studies have indicated that VCAM-1 expression is high in endometriosis; however, whether the expression of VCAM-1 is related to IL-33 is unclear. MATERIALS AND METHODS: Human ovarian endometriotic stromal cells (hOVEN-SCs) were treated with IL-33 to enable investigation of cell characterization, gene and protein expression, and signal pathways. Proliferation potential was measured using an MTT assay. Gene expression was analyzed using reverse transcription-polymerase chain reaction. Protein expression assay was performed using western blot analysis. RESULTS: This study investigated the effects of IL-33 on VCAM-1 and COX-2 expression in hOVEN-SCs. First, the results revealed that the IL-33/ST2/mitogen-activated protein kinase (MAPK) signaling pathway could increase the expression of VCAM-1 and COX-2 in hOVEN-SCs. Second, we discovered that COX-2 expression was essential for IL-33-induced VCAM-1 expression because the effects could be negated through NS398, a selective COX-2 inhibitor. Finally, treatment of IL-33-treated hOVEN-SCs with celecoxib significantly and dose-responsively decreased VCAM-1 expression. CONCLUSION: Taken together, these results indicate that IL-33 can upregulate VCAM-1 expression in hOVEN-SCs through the IL-33/ST2/MAPK/COX-2 signaling pathway and thereby contribute to endometriosis.

[Effects of human umbilical cord mesenchymal stem cells (MSCs)-derived exosomes on pulmonary vascular remodeling in hypoxic pulmonary hypertension].

The present study aimed to investigate the effect of human umbilical cord mesenchymal stem cells (MSCs)-derived exosomes (MSCs-Exo) on mice with hypoxic pulmonary hypertension (HPH). MSCs were isolated and cultured from human umbilical cords under aseptic conditions, and exosomes were extracted from the supernatants and identified. Healthy SPF C57BL/6 mice were randomly divided into three groups: normoxic group, hypoxic group, and hypoxic+MSCs-Exo group. Mice in the hypoxic group and the hypoxic+MSCs-Exo group were maintained for 28 d at an equivalent altitude of 5 000 m in a hypobaric chamber to establish HPH mouse model. The mice in the hypoxic+MSCs-Exo group were injected with MSCs-Exo via tail vein before hypoxia and on days 1, 3, 5 and 9 of hypoxia, and the mice in the other two groups were injected with PBS. At the end of the experiment, echocardiography was performed to detect pulmonary arterial acceleration time/pulmonary arterial ejection time ratio (PAAT/PET), right ventricular free wall thickness, and right ventricular hypertrophy index RV/(LV+S). HE staining was performed to observe the lung tissue morphology. EVG staining was performed to observe elastic fiber hyperplasia. Immunohistochemistry was performed to detect α smooth muscle actin (α-SMA) expression in lung tissue. Immunofluorescence staining was used to detect macrophage infiltration in lung tissue. qPCR was performed to detect IL-1ß and IL-33 in lung tissue, and cytometric bead array was performed to detect IL-10 secretion. Western blotting was used to detect the M1 macrophage marker iNOS, M2 macrophage marker Arg-1 and IL-33/ST2 pathway proteins in lung tissues. The results showed that hypoxia increased pulmonary artery pressure and pulmonary vascular remodeling, increased macrophage infiltration, IL-1ß and IL-33 expression (P < 0.05) and upregulated the IL-33/ST2 pathway (P < 0.05). Compared with the hypoxic group, MSCs-Exo treatment increased PAAT/PET (P < 0.05), decreased right ventricular free wall thickness (P < 0.05), right ventricular hypertrophy index RV/(LV+S) (P < 0.05), α-SMA expression in small pulmonary vessels (P < 0.05), and inflammatory factors including IL-1ß and IL-33 expression in lung tissue, however increased IL-10 secretion (P < 0.05). In addition, MSCs-Exo treatment upregulated Arg-1 and downregulated iNOS and IL-33/ST2 (P < 0.05). The results suggest that MSC-Exo may alleviate HPH through their immunomodulatory effects.

Influence of a 7-day Transalpine Trail Run on cardiac biomarkers and myocardial function.

Intense physical exercise is known to increase cardiac biomarkers; however, it is unclear, whether this phenomenon is physiological, or if it indicates myocardial tissue injury. The aim of our study was to investigate the effects of seven consecutive days of excessive endurance exercise on continuous assessment of cardiac biomarkers, function, and tissue injury. During a 7-day trail-running competition (Transalpine Run, distance 267.4 km, altitude ascent/descent 15556/14450 m), daily blood samples were obtained for cardiac biomarkers (hs-TnT, NT-proBNP, and suppression of tumorigenicity-2 protein (ST2)) at baseline, after each stage and 24-48 h post-race. In addition, echocardiography was performed every second day, cardiac magnetic resonance imaging (CMR) before (n = 7) and after (n = 16) the race. Twelve (eight males) out of 17 healthy athletes finished all seven stages (average total finish time: 43 ± 8 h). Only NT-proBNP increased significantly (3.6-fold, p = 0.009) during the first stage and continued to increase during the race. Hs-TnT revealed an incremental trend during the first day (2.7-fold increase, p = 0.098) and remained within the pathological range throughout the race. ST2 levels did not change during the race. All cardiac biomarkers completely returned to physiological levels post-race. NT-proBNP kinetics correlated significantly with mild transient reductions in right ventricular function (assessed by TAPSE, tricuspid annular plane systolic function; r = -0.716; p = 0.014). No significant echocardiographic changes in LV dimensions, LV function, or relevant alterations in CMR were observed post-race. In summary, this study shows that prolonged, repetitive, high-volume exercise induced a transient, significant increase in NT-proBNP associated with right ventricular dysfunction without corresponding left ventricular functional or structural impairment.

Dynamics of blaOXA-23 gene transmission in Acinetobacter spp. from contaminated veterinary environmental surfaces: an emerging One Health threat?

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii is a common pathogen associated with healthcare-acquired infections, and robust infection prevention and control protocols exist in human healthcare settings. In contrast, infection prevention and control (IPC) standards are limited in veterinary medicine, necessitating further investigation. AIM: Examine the possible transmission of carbapenem-resistant Acinetobacter spp. in a veterinary practice where a cat was diagnosed with an OXA-23-producing A. baumannii ST2 strain. METHODS: Environmental samples together with nasal and hand swabs from the veterinary personnel were collected. All swabs were screened for the presence of extended-spectrum-ß-lactamase- and carbapenemase-producing Enterobacterales, meticillin-resistant staphylococcus and multi-drug-resistant Acinetobacter spp. Whole-genome sequencing was performed for carbapenemase-producing strains. RESULTS: Of the veterinary staff, 60% carried meticillin-resistant Staphylococcus epidermidis. Environmental evaluation showed that 40% (N=6/15) of the surfaces analysed by contact plates and 40% (N=8/20) by swabs failed the hygiene criteria. Assessment of the surfaces revealed contamination with five OXA-23-producing Acinetobacter spp. strains: an OXA-23-producing Acinetobacter schindleri on the weight scale in the waiting room; and four OXA-23-producing Acinetobacter lwoffii strains, on different surfaces of the treatment room. The blaOXA-23 gene was located on the same plasmid-carrying Tn2008 across the different Acinetobacter spp. strains. These plasmids closely resemble a previously described OXA-23-encoding plasmid from a human Portuguese nosocomial Acinetobacter pittii isolate. Distinctly, the OXA-23-producing A. baumannii ST2 clinical strain had the resistant gene located on Tn2006, possibly inserted on the chromosome. CONCLUSION: The detection of an OXA-23-producing A. baumannii ST2 veterinary clinical strain is of concern for companion animal health and infection, prevention and control. This study established the dynamic of transmission of the plasmid-mediated blaOXA-23 gene on critical surfaces of a small animal veterinary practice. The genetic resemblance to a plasmid found in human nosocomial settings suggests a potential One Health link.

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

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

Persistence and evolution of linezolid- and methicillin-resistant Staphylococcus epidermidis ST2 and ST5 clones in an Italian hospital.

OBJECTIVES: Staphylococcus epidermidis is a member of the human skin microbiome. However, in recent decades, multidrug-resistant and hospital-adapted S. epidermidis clones are increasingly involved in severe human infections associated with medical devices and in immunocompromised patients. In 2016, we reported that a linezolid- and methicillin-resistant S. epidermidis ST2 clone, bearing the G2576T mutation, was endemic in an Italian hospital since 2004. This study aimed to retrospectively analyse 34 linezolid- and methicillin-resistant S. epidermidis (LR-MRSE) strains collected from 2018 to 2021 from the same hospital. METHODS: LR-MRSE were typed by Pulsed-Field Gel Electrophoresis and multilocus sequence typing and screened for transferable linezolid resistance genes. Representative LR-MRSE were subjected to whole-genome sequencing (WGS) and their resistomes, including the presence of ribosomal mechanisms of linezolid resistance and of rpoB gene mutations conferring rifampin resistance, were investigated. RESULTS: ST2 lineage was still prevalent (19/34; 55.9%), but, over time, ST5 clone has been widespread too (15/34; 44.1%). Thirteen of the 34 isolates (38.2%) were positive for the cfr gene. Whole-genome sequencing analysis of relevant LR-MRSE displayed complex resistomes for the presence of several acquired antibiotic resistance genes, including the SCCmec type III (3A) and SCCmec type IV (2B) in ST2 and ST5 isolates, respectively. Bioinformatics and polymerase chain reaction (PCR) mapping also showed a plasmid-location of the cfr gene and the occurrence of previously undetected mutations in L3 (ST2 lineage) and L4 (ST3 lineage) ribosomal proteins and substitutions in the rpoB gene. CONCLUSION: The occurrence of LR-MRSE should be carefully monitored in order to prevent the spread of this difficult-to-treat pathogen and to preserve the efficacy of linezolid.

Two regulatory T cell populations in the visceral adipose tissue shape systemic metabolism.

Visceral adipose tissue (VAT) is an energy store and endocrine organ critical for metabolic homeostasis. Regulatory T (Treg) cells restrain inflammation to preserve VAT homeostasis and glucose tolerance. Here, we show that the VAT harbors two distinct Treg cell populations: prototypical serum stimulation 2-positive (ST2+) Treg cells that are enriched in males and a previously uncharacterized population of C-X-C motif chemokine receptor 3-positive (CXCR3+) Treg cells that are enriched in females. We show that the transcription factors GATA-binding protein 3 and peroxisome proliferator-activated receptor-γ, together with the cytokine interleukin-33, promote the differentiation of ST2+ VAT Treg cells but repress CXCR3+ Treg cells. Conversely, the differentiation of CXCR3+ Treg cells is mediated by the cytokine interferon-γ and the transcription factor T-bet, which also antagonize ST2+ Treg cells. Finally, we demonstrate that ST2+ Treg cells preserve glucose homeostasis, whereas CXCR3+ Treg cells restrain inflammation in lean VAT and prevent glucose intolerance under high-fat diet conditions. Overall, this study defines two molecularly and developmentally distinct VAT Treg cell types with unique context- and sex-specific functions.

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

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

Soluble ST2 as a possible biomarker for inflammation in patients with acute heart failure.

AIM: The aim of this study was to explore the relationship between peripheral circulating serum soluble suppression of tumorigenicity-2 (sST2) levels and inflammatory biomarkers in patients with acute heart failure (AHF). METHODS: One hundred and eleven consecutive AHF patients with NYHA class II-IV were enrolled, and peripheral blood was collected within 24 h of admission for the detection of NT-ProBNP, sST2, hypersensitive troponin I, cytokines, precalcitoninogen, C-reactive protein, in addition to routine standard of care blood tests. RESULTS: The median sST2 of 111 patients was 47.50 ng/ml (24.25-86.15 IQR), of whom 43 patients (38.7%) had sST2 35 ng/ml or less; linear correlation analysis showed that serum sST2 correlated with NT-ProBNP ( r2  = 0.32), NEU% ( r2  = 0.41), NLR ( r2  = 0.36), CRP ( r2  = 0.50), IL-18 ( r2  = 0.43) ( P  < 0.001), and correlated with Hs-cTnI ( r2  = 0.19), NUE ( r2  = 0.25), LYM ( r2  = -0.23), IL-2RA ( r2  = 0.29) ( P  < 0.05). Multiple linear regression analysis depicted that CRP (ß = 0.318), IL-18 (ß = 0.368), NEU% (ß = 0.346), NLR (ß = -0.304), and NT-ProBNP (ß = 0.324) significantly correlated with sST2 values, respectively ( P  < 0.05). ST2 levels have a linear association with length of hospitalization. CONCLUSION: Peripheral blood inflammatory markers (CRP, IL-18, NEU%, NLR) in patients with AHF had a close relationship with sST2 levels, and the mechanism of action of sST2 may be related to the inflammatory response.