Search Results (639)

Helminths infect a quarter of the human population and are controlled in the frame of a canonical type-2 immune response. Interleukin-9 is a cytokine with pleiotropic functions during type-2 immunity that can be produced by many different cells. Accumulating evidence suggest that IL-9 is of particular relevance in controlling intestinal helminth infections. Using mice infected with the parasitic nematode Strongyloides ratti, we showed previously that ejection from the intestine depends on IL-9 and IL-9-mediated activation of mucosal mast cells. Here we use IL-9 reporter mice to identify the relevant cellular sources of IL-9 in vivo. We report that predominantly CD4⁺ T cells and group 2 innate lymphoid cells (ILC2s) produced IL-9 in S. ratti-infected or IL-33-treated mice. Interestingly, the IL-33-mediated induction of IL-9 and subsequent mast cell degranulation was modulated by concurrent S. ratti infection. While the IL-33-mediated expansion of IL-9-producing ILC2s was supressed by S. ratti infection, IL-9-producing CD4⁺ T cells were proportionally increased. Finally, we show that S. ratti-derived E/S products interfered with IL-9 production by BM-derived ILC2 in vitro. In conclusion, we have identified that ILC2 and CD4⁺ T cells produce IL-9 during S. ratti infection, and that ILC2 responses are suppressed by S. ratti products. Full article

Epidemiological data link a lack of breastfeeding with an increased risk of breast cancer. Breast tissue remodels after pregnancy through involution. Long-term breastfeeding results in gradual involution (GI), and a lack of breastfeeding leads to abrupt involution (AI). AI causes increased mammary gland estrogen signaling, causing adipocyte redifferentiation through neutrophil infiltration. Adipocyte differences and metabolic implications of involution have not been explored between AI and GI. As breast cancer is characterized as highly metabolic, we explored how adipocyte differences and metabolism during involution may support breast cancer risk. FVB/n was randomized to AI/GI and standardized to 6 pups on day 0/birth. AI mice had pups removed on day 7. GI mice had 3 pups removed on days 28 and 31. Mammary glands were harvested at 28, 56, and 120 days. A subset of AI mice were given tamoxifen for 21 days. Day 28 AI glands had upregulation of estrogen signaling, neutrophil degranulation, and glucose metabolism and downregulation of adipogenesis and glycolysis compared to Day 56 GI. Day 120 AI glands had downregulation of oxidative phosphorylation and upregulation of mitochondrial dysfunction similar to estrogen receptor-negative (ER−) pregnancy-associated breast cancer (PABC). AI with tamoxifen resulted in a similar metabolic phenotype to GI. Early metabolic phenotypes in AI and GI glands may be related to estrogen signaling. AI long-term transcriptional metabolic effects were similar to breast cancer. Full article

Mast cells (MCs) are innate immune cells that are derived from CD34⁺ hematopoietic stem/progenitor cells (HSPCs) and mature in peripheral tissues such as skin and mucosa. Mature human MCs can be generated from peripheral blood, but this process requires substantial blood volumes as HSPC frequencies are typically very low. The aim of this study was to validate a new in-house-developed protocol for the generation of MCs from less than 20 mL of peripheral blood. To this end, we used a magnetic bead-based procedure to isolate ‘untouched’ HSPCs from 14 to 16 mL peripheral blood (PB). In total, 12 cultures were set up with blood from seven healthy donors, wherein HSPCs were first expanded for 4 weeks, followed by another 8 weeks of culture in MC maturation-inducing medium. Flowcytometric analysis, histochemical staining, and degranulation assays were used to assess their phenotypic and functional features. Our data show comparable expression of cytoplasmic granules and cell-surface expression of MRGPRX2, FcεR1α, and CD117 in 8/12 blood-derived MCs (PB-MCs) and buffy coat-derived HSPCs (BC-MCs). PB-MCs responded to classic stimulating agents like IgE/anti-IgE and C48/80. Hence, our novel MC generation protocol yields functionally competent MCs with no compromise in their maturation or activation potential despite 12 weeks of in vitro culture. Full article

Food allergies (FA) are a major public health concern in both children and adults. Immunoglobulin E (IgE)-mediated FA is characterized by allergic reactions driven by allergen-specific IgE and the subsequent degranulation of mast cells and basophils. Current FA management primarily involves avoidance of allergen-containing food, and more recently, therapies such as oral immunotherapy (OIT), sublingual immunotherapy (SLIT), and the anti-IgE biologic omalizumab. However, these interventions are not curative. The gut microbiome has been implicated in the development and regulation of oral tolerance to food antigens. This narrative review explores the role of probiotics, fecal microbiota transplantation (FMT), dietary interventions, and the interaction between the microbiome and OIT as potential strategies to manage established FA. We also explore barriers to their proliferation as part of regular clinical care. We conclude that future research should (1) address how the microbiome interacts with immunotherapies other than OIT, (2) explore the role of novel microbiome-based treatments like FMT as potential adjuvants to existing food allergy therapeutics, and (3) focus on developing standardized protocols and endpoints for microbiome-based therapeutics. Full article

Natural compounds have experienced increasing clinical application, but their association with rapid-onset anaphylactoid reactions (ARs) present a significant challenge to their safe use. These ARs, clinically resembling Type I hypersensitivity, are non-IgE-mediated and involve direct mast cell activation, primarily through the human Mas-related G protein-coupled receptor X2 (MRGPRX2). We computationally screened a natural compound library for MRGPRX2 activation. A human MRGPRX2-expressing cell model was established. Cell viability assays (0–80 μM) were performed to determine appropriate drug concentrations. Compared to the controls, Baohuoside I (10 μM), along with Kaempferol-3-O-rutinoside, Epigallocatechin gallate (EGCG), Isochlorogenic Acid B, Baicalin, Andrographolide, Isorhamnetin, and Dehydroandrographolide (all at 20 μM), significantly increased intracellular calcium flux (p < 0.05) and boosted tryptase and β-hexosaminidase secretion (ELISA) (p < 0.05) in mast cells. Furthermore, the degranulation induced by these compounds was inhibited by the MRGPRX2 inhibitor Z3578 at 20 μM. Neutral red staining was employed to observe cellular morphological changes. Specific compounds capable of mediating ARs through MRGPRX2 activation on mast cells were identified. This contributes to safer and more effective drug use by elucidating the potential triggers of ARs. Full article

Background/Objectives: In clinical practice today, platelet concentrates are often used for topical surgical applications. They are biomaterials that can accelerate healing processes associated with oral and maxillofacial surgery as well as in several other clinical applications through the action of growth factors released by platelets at the surgical site. However, in most cases, the exact quantification of the released growth factors is challenging in both the short and long term. The aim of this study was to determine if early platelet activation and degranulation occur during the collection and utilization of platelet-rich plasma (PRP) in the surgical room, where, before its application, PRP undergoes a procedure of gelification via reactions with procoagulant agents. Methods: PRP was prepared from the blood samples of 39 patients following the modified Whitman protocol. The samples were then analyzed at four different time points (1, 6, and 24 h during preparation and clinical application in the surgery room) using flow cytometry and enzyme-linked immunosorbent assays (ELISAs) to investigate the platelet activation/degranulation and TGFβ release in the supernatant (SN) during storage and clinical application. The mean platelet count in the whole blood was 267.5 ± 48.58 × 10³/mL (range: 189–334 × 10³/mL), and the mean concentration was 2925.5 ± 833.37 × 10³/mL (range: 748–3453 × 10³/mL). Results: The activation and degranulation of platelet cells (measured via monoclonal antibodies: CD62p and CD63, respectively) demonstrated a progressive increase at 1 h, 6 h, 24 h, and after gelification. The TGFβ dosage in the supernatant (SN) at different times exhibited a similar trend, with a mean release of 18.36 ng/mL at 1 h, 21.96 ng/mL at 6 h, and 29.45 ng/mL at 24 h. After the gelification of the PRP, a significant reduction was observed, with a value of 15.52 ng/mL. Conclusions: The results reveal that the protocol used for the preparation, storage, and application of the PRP ensures a good-quality hemoderivative and that the platelet concentrate must be applied with the correct timing to support tissue healing processes. Full article

Background: Neurodegeneration and dementia are key factors in Alzheimer’s disease (AD). The deposition of amyloid-ß into senile plaques in the brain parenchyma and in cerebral vessels known as cerebral amyloid angiopathy (CAA) are the main clinical parameters of AD. Acute myocardial infarction (AMI) and AD share a comparable pathophysiology. However, the underlying mechanisms and the consequences of AMI in AD patients are unclear to date. Methods: AD transgenic APP23 mice were analyzed in experimental AMI using the closed-chest model. Results: APP23 mice displayed significantly decreased left ventricular function as detected by FS/MPI (fractional shortening/myocardial performance index) after 24 h and 3 weeks after ligation of the LAD compared to WT controls. No differences have been observed in infarct and scar size. The analysis of cardiac remodeling after 3 weeks showed an altered composition of the collagen tissue of the scar with elevated tight but reduced fine collagen in APP23 mice. Altered scar formation was accompanied by elevated degranulation of platelets following activation of the collagen receptor GPVI. Conclusions: These results suggest that AD patients are at higher risk for cardiac damage after AMI. This implies the need for a personalized therapy of AMI in AD patients. Full article

Background: Vasicine (Vas) is a quinazoline alkaloid derived from Adhatoda vasica Nees, which has good anti-allergic asthma and anti-inflammatory effects. However, its specific functional mechanism on allergic asthma is unclear. This study aims to investigate the protective effect of Vas on allergic asthma and its underlying mechanisms. Methods: Initially, the therapeutic effects of Vas were assessed in ovalbumin-sensitized BALB/c mice using airway hyperresponsiveness (AHR), histopathological examinations, immunohistochemistry, and enzyme-linked immunosorbent assays (ELISA). Subsequently, a non-targeted metabolomic analysis was performed to examine the influence of Vas on lung metabolites, while molecular docking was utilized to clarify the mechanisms by which Vas intervenes in allergic asthma. Lastly, RBL-2H3 cells were employed in vitro to validate the metabolomic findings by measuring intracellular Ca²⁺ concentrations, in addition to conducting ELISA and Western blot analyses. Results: In vivo, Vas alleviates AHR in mice with allergic asthma, enhances histopathological conditions, and reduces inflammatory factors. Non-targeted metabolomics analyses indicate that the primary pathway implicated in its intervention in allergic asthma may be the FcεRI pathway. Furthermore, molecular docking techniques were utilized to evaluate the binding affinity between Vas and proteins associated with this pathway. In vitro, Vas effectively inhibits degranulation in RBL-2H3 cells and diminishes the release of inflammatory factors by modulating the FcεRI/Lyn + Syk/MAPK pathway. Conclusions: These findings indicate that Vas may effectively alleviate allergic asthma by reducing inflammatory responses, decreasing AHR, and improving histopathological features. Furthermore, Vas seems to inhibit mast cell degranulation and modulate the FcεRI/Lyn + Syk/MAPK pathway. Full article

Arteriogenesis, the growth of pre-existing arterioles into functional collateral arteries, represents a key adaptive response to severe arterial stenosis. This process is driven by hemodynamic forces and a tightly coordinated inflammatory cascade. Here, we investigated the effects of pharmacological stimulation of the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) signaling pathway using the phosphodiesterase-5 (PDE5) inhibitor Sildenafil on collateral vessel growth in a murine model of femoral artery ligation (FAL). Flow cytometric analyses revealed that Sildenafil treatment significantly enhanced platelet–leukocyte aggregate formation, a prerequisite for the subsequent initiation of a localized perivascular inflammation. Histological and immunofluorescence analyses further demonstrated a marked increase in mast cell recruitment and degranulation at early time points (days 1 and 3 post-FAL). In addition, Sildenafil promoted perivascular macrophage accumulation on days 3 and 7, with a pronounced shift toward an M2-like pro-regenerative polarization state, ultimately resulting in the enhanced proliferation of vascular cells and the enlargement of collateral diameters. Together, these findings identify Sildenafil as a potent enhancer of arteriogenesis through coordinated immune cell activation, stimulating vascular cell proliferation along with positive collateral outward remodeling. Thus, Sildenafil emerges as a promising therapeutic candidate to promote collateral artery growth in cardiovascular occlusive diseases. Full article

Nickel allergy remains the most prevalent cause of allergic contact dermatitis worldwide, imposing a substantial socio-epidemiological and economic burden. Beyond its classical cutaneous presentation, systemic nickel allergy syndrome highlights the systemic dimension of Nickel hypersensitivity, wherein dietary nickel intake may provoke both gastrointestinal and cutaneous symptoms through mechanisms involving gut barrier impairment and mucosal immune priming. Recent evidence highlights the contribution of angiogenesis and lymph-angiogenesis to Nickel-induced allergic contact dermatitis, through crosstalk among keratinocytes, mast cells, endothelial cells, and pro-angiogenic mediators such as vascular endothelial growth factor. Against this background, we propose to revisit palmitoylethanolamide, an endogenous ALIAmide with well-documented anti-inflammatory, anti-angiogenic, and anti-allergic properties. Already studied in pain and inflammatory disorders and employed in veterinary dermatology, palmitoylethanolamide down-modulates mast cell degranulation, suppresses VEGF expression via PPAR-α/Akt/mTOR signaling, and enhances intestinal barrier integrity, acting as a promising “gatekeeper” molecule that reduces gut hyperpermeability characterizing systemic nickel allergy as well as other gut disorders with systemic consequences. This paper is presented as a viewpoint intended to highlight the untapped therapeutic potential of palmitoylethanolamide, suitable for both oral and topical administration, as a candidate to address the multifactorial pathophysiology of Nickel allergic contact dermatitis and systemic nickel allergy. Our purpose is not to provide definitive answers, but to stimulate scientific debate on its rational use within emerging gut–skin therapeutic strategies. We thus encourage future experimental and clinical studies to explore its potential integration within emerging gut–skin therapeutic paradigms. Full article

Ozone (O₃) is a reactive oxidant increasingly applied in biomedical settings, yet its dose-dependent effects on innate immune cells, particularly those from non-human species, remain insufficiently defined. Within a One Health framework, this study examined how two clinically relevant O₃ exposure regimens (30 µg/mL and 90 µg/mL) affect porcine neutrophils and monocytes isolated from peripheral blood. Cell viability, reactive oxygen and nitrogen species (RONS) production, and the activity of key enzymes (myeloperoxidase, elastase, alkaline phosphatase, arginase) were assessed at 1 h and 24 h post-exposure. The lower dose induced mild functional activation without compromising viability, whereas the higher dose triggered pronounced oxidative stress, enhanced degranulation, and reduced neutrophil viability by more than 60%. Neutrophils exhibited a stronger and more dynamic response than monocytes, which retained viability and differentiation capacity at 30 µg/mL but showed impaired function at 90 µg/mL. These findings highlight the dual nature of O₃, where controlled exposure may support immunomodulation, while excessive dosing disrupts cell function. Defining safe and effective therapeutic windows remains critical for future applications. Full article

Background: The recently defined pachychoroid disease spectrum (PDS), which includes central serous chorioretinopathy (CSCR), is a group of retinal disorders that share the common characteristic of a thick, dilated, hyperpermeable choroid. This study aimed to evaluate the efficacy of difluprednate and loratadine in the treatment of pachychoroid disease spectrum (PDS). Methods: A retrospective study of 27 eyes from 19 patients with macular edema secondary to chronic PDS were treated with topical difluprednate and oral loratadine at a tertiary medical center. Visual acuity and optical coherence tomography (OCT) images were analyzed at baseline, 1-, 2-, 3-, 6-, 12-month, and final follow-up. Baseline was defined as the initiation of topical difluprednate. Patients with neovascularization or who had other concurrent treatments for PDS were excluded. Subfoveal choroidal thickness was measured at each time point. Response was defined as eyes that showed a reduction in intra- or subretinal fluid. Results: All 27 eyes studied responded to treatment. Of these, 70.4% resolved by 4 months and 81.5% by 6 months, with 52.2% of these patients having recurrences related to cessation or tapering of topical steroids. Visual acuity remained stable (p > 0.05) while subfoveal choroidal thickness decreased compared to baseline (p < 0.001) across all time points. Eleven (40.7%) of the eyes developed increased intraocular pressure, for which seven (25.9%) required incisional surgery. Conclusions: Chronic PDS can be treated with a combination of topical difluprednate and oral antihistamines to reduce retinal edema and subfoveal choroidal thickness. The effectiveness of therapy could be linked to the regulation of mast cell degranulation, necessitating a well-powered prospective randomized clinical trial. Full article

The Mas-related G protein-coupled receptor (MRGPR) X2 is expressed on skin mast cells and can be stimulated by an unusually broad spectrum of ligands, including specific drugs and even endogenous peptides. MRGPRX2 activation can induce mast cell degranulation and consequently mediator release, leading to inflammatory and hypersensitivity reactions. In addition, MRGPRX2 mediates pain and itching sensations, leading to increased efforts to identify MRGPRX2 inhibitors, including plant-derived compounds. Components within oat extracts have been shown to mediate anti-inflammatory and itch-relieving properties, but a possible inhibitory effect on MRGPRX2 activation has not yet been investigated. We aimed to fill this gap and explored whether an oat kernel extract can modulate MRGPRX2 activation. For this purpose, we established a mast cell model with the human LAD2 cell line and used it to investigate the consequences of exposure to oat extract. While we did not observe any influence on cell viability, we analyzed the impact of oat extract on MRGPRX2-mediated mast cell activation and degranulation initiated by the three confirmed MRGPRX2 ligands c48/80, substance P, and cortistatin 14. Exposure to oat extract resulted in a significant reduction in mast cell degranulation for all three ligands, as assessed by the release of β-hexosaminidase, tryptase, cell surface expression of CD63 and CD107a, and phosphorylation of ERK. All results were confirmed with primary human mast cells. Thus, we demonstrated for the first time that oat extract leads to a significant reduction in MRGPRX2 activation, pointing to a previously unrecognized capacity of natural compounds to modulate this pathway. Full article

Neuroinflammation is a common pathophysiological feature of many disorders affecting the central nervous system, including migraine—one of the most prevalent neurological conditions, which significantly impairs quality of life, particularly when it progresses to the chronic form. The aim of the present study was to analyze oxidative changes following a single administration of nitroglycerin (NTG), as well as to investigate alterations in the glial microenvironment and inflammatory processes induced by chronic NTG administration. Registration of biosensor signals (HyPer7 and SypHer3s) in vivo did not reveal changes in hydrogen peroxide levels or pH following single NTG administration in striatum and cortex. In contrast, analysis of chronic NTG administration indicates neuroinflammatory processes occurring in the thalamus and the dentate gyrus of the hippocampus, but not in the somatosensory cortex without disruption of the BBB and decreased degranulation of meningeal mast cells. We observed a decrease in the mRNA expression in the thalamic tissue of the neuroprotective transforming growth factor beta 1 gene and an increase in the expression of the pro-inflammatory interferon gamma. The regional specificity of neuroinflammation supports the suggestion that maladaptive changes in these structures could play a critical role in the transition from episodic to chronic migraine. Full article

Migraine is characterized by severe pain and somatic symptoms like allodynia and photophobia, driven by neuroinflammation that sensitizes the trigeminal vascular system (TVS). This study investigated how neuroinflammation induced by systemic lipopolysaccharide (LPS) affects migraine-related nociceptive signaling. Using a chronic migraine model in rats with nitroglycerin (NTG), we compared prenatal and acute postnatal LPS administration. Rats with prenatal LPS exhibited lower mechanical thresholds and enhanced allodynia and photophobia after NTG. Acute LPS also increased allodynia, but not photophobia. Both LPS groups showed increased mast cell degranulation in the dura mater. Plasma CGRP after NTG administration was elevated in the acute LPS group. Electrophysiology revealed enhanced trigeminal afferent responses to serotonin in both acutely and prenatally LPS-treated rats. Calcium imaging demonstrated increased neuronal responses to serotonin and capsaicin, suggesting an upregulation of serotonin and TRPV1 receptors. Our findings show that LPS-induced neuroinflammation, whether prenatal or acute, promotes sensitization of peripheral and central nociceptive pathways, involving serotoninergic mechanisms. Full article