Search Results (78)

Background: Polymorphonuclear (PMN) leukocyte recruitment to activated pulmonary endothelium is a central mechanism in acute respiratory distress syndrome (ARDS). This process is mediated by selectins and their counter-ligand, P-selectin glycoprotein ligand-1 (PSGL-1), encoded by SELPLG. Genetic variation in SELPLG has been associated with ARDS susceptibility, while disruption of PSGL-1/P-selectin interactions attenuates lung injury in preclinical models. Because inflammatory stimuli increase both SELPLG expression and circulating PSGL-1 levels, PSGL-1 represents a promising biomarker and therapeutic target. We sought to define the genetic determinants of plasma PSGL-1 levels and evaluate their causal relationships with key inflammatory and endothelial biomarkers. Methods: Genome-wide association study (GWAS) summary statistics for plasma PSGL-1 levels were obtained from the UK Biobank Pharma Proteomics Project (n = 35,571) and the SCALLOP consortium (n = 21,758 across 13 cohorts). Associated variants underwent functional annotation and in silico analyses to identify potential effects on protein structure and gene regulation. Bidirectional Mendelian randomization (MR) was performed using GWAS summary statistics for C-reactive protein (CRP), E-selectin, GlycA, and soluble intercellular adhesion molecule-1 (sICAM-1) to assess potential causal relationships with PSGL-1 levels. Results: Multiple cis- and trans-acting loci were significantly associated with plasma PSGL-1 concentrations. Three coding SELPLG variants (rs201689859, rs74792300, and rs139943851) were predicted to alter PSGL-1 protein structure and were associated with lower circulating PSGL-1 levels. Four promoter variants (rs1420663, rs1833245, rs1420664, and rs8179110) were linked to altered transcriptional activity, including a potential effect of rs1420664 on hypoxia-inducible factor binding. Bidirectional MR demonstrated that genetically predicted CRP, E-selectin, GlycA, and sICAM-1 levels were associated with increased plasma PSGL-1 concentrations. Additional loci implicated pathways related to immune signaling, cell adhesion, and protein stability. Conclusions: Large-scale GWAS and Mendelian randomization analyses identified genetic variants that regulate plasma PSGL-1 levels and demonstrated causal links between inflammatory and endothelial biomarkers and PSGL-1 expression. These findings provide new insights into the genetic regulation of leukocyte trafficking pathways and support a role for PSGL-1 in inflammatory diseases, including ARDS, sepsis, and cardiovascular disorders. Full article

The vascular endothelial glycocalyx (EGX) is a gel-like, negatively charged mesh of membrane-bound proteoglycans, glycosaminoglycans, glycoproteins and adsorbed plasma proteins that covers the luminal surface of the endothelium and orchestrates vascular homeostasis through regulation of permeability, leukocyte trafficking, mechanotransduction and anti-thrombotic signalling. Progressive thinning, heterogeneous remodelling and accelerated shedding of the EGX are now recognised as hallmarks of vascular ageing and early drivers of age-related cardiovascular disease. Here, we synthesise current evidence linking EGX integrity to biological ageing, with emphasis on age-dependent remodelling of heparan-sulfate proteoglycans, endothelial progenitor-cell dysfunction, and the heightened susceptibility of the aged EGX to oxidative, inflammatory and infectious insults. We discuss signalling pathways driving EGX shedding—including the IQGAP1/PAR1-2/PI3K/Akt axis—and clinical correlates such as vulnerable coronary plaque in older patients with coronary artery disease and microvascular endotheliopathy in severe COVID-19. Finally, we review emerging anti-ageing strategies targeting the EGX, including direct oral anticoagulants, glycocalyx-mimetic and nitric-oxide-releasing biomaterials, bioinspired antithrombogenic surfaces and microbiome-based modulation, and consider their translational potential for extending cardiovascular healthspan. Full article

Leukocyte recruitment from blood into tissues involves sequential adhesive steps, including rolling and integrin-dependent arrest. VLA-4 can support firm adhesion and, in some settings, rolling interactions, whereas CD44–hyaluronan interactions have also been implicated in leukocyte rolling. Here, we used adhesion assays and parallel-plate flow chamber experiments to analyze CD44–hyaluronan-dependent monocyte interactions on ECV304 monolayers and to compare them with α4-integrin-sensitive adhesion on endothelial monolayers. WEHI 78/24 monocytoid cells interacted with ECV304 monolayers in a CD44- and hyaluronan-dependent manner, whereas adhesion to HMEC-1 and bEnd.3 monolayers was sensitive to α4-integrin blockade. Blocking CD44, adding soluble hyaluronan, or treating ECV304 monolayers with hyaluronidase reduced adhesion and rolling. Mixed primary human monocyte preparations also showed CD44-dependent adhesion and rolling on ECV304 monolayers. ECV304 cells are interpreted here not as endothelial cells, but as T24-derived, hyaluronidase-sensitive cellular monolayers useful for functional analysis of CD44–hyaluronan-dependent interactions. These findings support a substrate-dependent functional hierarchy in which CD44–hyaluronan-dependent monocyte rolling becomes detectable when α4-integrin-dependent adhesion is not dominant, while emphasizing the cell-model-based nature of the assay. Full article

The hallmarks of allergic diseases are Type 2 immunity, including IL-4 and IL-13 production, IgE antibody generation, mast cell and basophil activation, histamine release, and eosinophil activation. There are many routes by which such mediators can influence CNS biology, including cytokine entry or signaling via brain barrier receptors; leukocyte trafficking across activated barriers; cytokine signaling via circumventricular organ sites or dural immune compartments; vagus nerve afferent signaling; mast cell degranulation; and histamine neuromodulation. Neuroinflammation is a common hallmark of many neurodegenerative diseases, but whether and to what degree allergic/type 2 immune biology may be involved depends on the specific disease stage and pathology. Here, we assess studies connecting the roles of IL-4/IL-13 signaling, IgE/mast cell activation, eosinophil-attractive chemokines, and histamines in Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis, dementia with Lewy bodies, Huntington’s disease, prion disease, and tauopathy/atypical parkinsonism. Mechanisms appear most clear in the case of Parkinson’s disease, where epidemiology suggests an important role in dementia/Alzheimer’s disease, while for other neurodegenerative conditions the evidence is less compelling and may be either mechanistic or modulatory. Confounding issues include sex differences, drug exposures, comorbid conditions, socioeconomic factors, and coexisting inflammatory diseases. Finally, we suggest a strategy based on longitudinal immune phenotyping, CNS biomarkers, and pathway manipulation to assess the relationship between allergic immune signaling and neurodegeneration. Full article

Since the first approval of CTLA-4 blockade for melanoma, immune checkpoint inhibitors (ICIs) have expanded into a major class of cancer therapy, with more than 100 FDA-approved oncological indications across metastatic and earlier-stage disease settings, including use as monotherapy and in combination regimens. Preclinical research has largely focused on myocarditis and atherosclerosis, but a wider set of phenotypes, such as non-inflammatory left ventricular dysfunction (NILVD), arrhythmias, and vasculitis, can be observed, and they are rarely connected within a single mechanistic model. We aim to build a systems-oriented, mechanistic framework of the most widely studied biological processes; it will link the main checkpoint pathways to relevant cardiac and vascular cell types, molecular pathways, immune synapses, and candidate biomarkers. We searched PubMed, Scopus, and Web of Science using combinations of terms for immune checkpoint inhibition and cardiovascular-immune-related adverse events that provide mechanistic insight into cardiac-immune-related adverse reactions (irAEs). An AI-assisted semantic clustering approach was used only to organize the included literature. The integrated framework identifies PD-1/PD-L1 as the dominant mechanistic hub linking T-cell activation, endothelial recruitment, myocardial injury, and vascular inflammation. Across phenotypes, a shared immune core involving checkpoint pathways, cytokine signaling, and leukocyte trafficking coexists with phenotype-restricted mediators that may bias injury toward myocarditis, vascular inflammation, conduction-system disease, or NILVD. KEGG analyses support the enrichment of T-cell receptor signaling, Th17 differentiation, JAK-STAT signaling, cytokine–cytokine receptor interaction, and lipid and atherosclerosis pathways. Candidate biomarkers emerging from the reviewed literature include troponin, IL-6, CXCL9/CXCL10/CXCL13, S100A family proteins, ROCK2, HLA-linked susceptibility signals, and T-cell receptor clonality markers. The AI-assisted clustering broadly recapitulated the expert-defined thematic structure while identifying finer semantic neighborhoods within the literature. This framework provides a support map for further hypotheses about toxicity patterns with current and next-generation checkpoint strategies on the cardiac system, while AI-assisted clustering provides a complementary method for organizing the literature rather than an independent source of biological inference. Full article

The endothelial glycocalyx (EG) is a dynamic endothelial surface layer composed of proteoglycans, glycosaminoglycans, glycoproteins, and adsorbed plasma proteins that regulates permeability, mechanotransduction, leukocyte trafficking, coagulation, and nitric oxide signaling. In kidney transplantation (KT), the EG is exposed to cumulative injury from recipient uremia, donor instability, preservation, machine perfusion, reperfusion, rejection, and immunosuppressive toxicity. This narrative review summarizes EG biology in KT, with emphasis on biomolecular findings relevant to ischemia–reperfusion injury, delayed graft function, rejection, and chronic allograft injury. Particular attention is given to syndecan-1, heparan sulfate, heparanase, soluble thrombomodulin, matrix metalloproteinases, angiopoietin-2/Tie2 signaling, selectins, miR-126, extracellular vesicles, and urinary or perfusate-derived readouts. Current evidence is biologically coherent but uneven: human data are largely observational, whereas many therapeutic concepts remain preclinical or exploratory. Glycocalyx-centered phenotyping may eventually improve risk stratification and trial enrichment, but clinical implementation will require standardized sampling, sample-source-aware biomarker panels, prospective validation, and clear separation between mechanistic plausibility and proven clinical utility. Full article

Physically active individuals demonstrate enhanced immune competence. Efficient execution of effector function relies on chemokine receptor-regulated immune cell trafficking along chemokine gradients to sites of inflammation, infection, tumors, or tissue damage. This study investigates the impact of acute high-intensity interval training (HIIT) on chemokine receptor expression in leukocytes. Sixteen healthy participants completed a single HIIT session, and peripheral blood was collected before exercise (Bsl), immediately after (Ex02), and one hour later (Ex60). Surface expression of selected chemokine receptors was measured using flow cytometry on CD4⁺ T cells, γδ T cells, NK cells, and monocytes, followed by FlowSOM clustering. NK cells, CD4⁺ T cells, and γδ T cells were strongly mobilized at Ex02 and returned to or below baseline at Ex60. HIIT preferentially mobilized CX3CR1⁺ CXCR2⁺ CD56^dim NK cells, CD4⁺ T cells expressing CX3CR1^hi and CCR5⁺, and CX3CR1⁺ CD56⁺ γδ T cells, indicating mobilization of immune cells phenotypically associated with migratory and cytotoxic potential. Proportions of intermediate and non-classical monocytes increased at Ex02 and decreased at Ex60. In conclusion, HIIT induced a rapid redistribution of leukocyte subsets with chemokine receptor profiles suggesting enhanced endothelial interaction and migratory capacity toward effector tissues. Full article

Leukocyte-specific protein 1 (LSP1) is known as an endothelial gatekeeper because it controls endothelial permeability and transendothelial cell migration, including that of leukocytes and potentially metastatic cancer cells. In endothelial cells, LSP1 is predominantly in the nucleus under resting conditions but translocates to extranuclear compartments upon stimulation with TNF-α. The discrepancy between its predicted molecular weight (~37 kDa) and its observed migration on SDS-PAGE (≥52 kDa), along with its dynamic subcellular distribution, suggests a possible post-translational modification by SUMOylation. To investigate this, we examined endogenous LSP1 in murine primary endothelial cells and overexpressed recombinant LSP1 in murine endothelial (SVEC4-10EE2) and HEK293T cells. Our results demonstrate that LSP1 is SUMOylated by SUMO1, with Ubc9 serving as the conjugating enzyme and SENP1 as the deSUMOylating protease. Site-directed mutagenesis of lysines K270 and K318 abolished SUMOylation, resulting in a marked reduction in LSP1 steady-state levels. This reduction was attributed to enhanced ubiquitination and accelerated proteasomal degradation of LSP1 in the SUMOylation-deficient state. Furthermore, deSUMOylation impaired the TNF-α-induced translocation of LSP1 from the nucleus to extranuclear compartments, particularly the cytoskeleton. In summary, our findings establish that LSP1 is a SUMO1-modified protein. SUMOylation stabilizes LSP1 by preventing proteasomal degradation and is essential for its proper subcellular trafficking in endothelial cells in response to inflammatory stimuli. Full article

Myocarditis is an inflammatory disease of the heart characterized by a complex interplay between innate and adaptive immune responses. The innate immune system provides first-line defense and includes soluble molecules, including macrophages, neutrophils, dendritic cells, and molecular mediators, but lacks immunological memory. In contrast, the adaptive immune system, via T and B lymphocytes, offers high specificity and long-term memory, which can sometimes target myocardial tissue, causing autoimmune injury. Particularly, acute myocarditis is characterized by dysregulated immune signaling, with cytokines (IL-2, IFN-γ, IL-12, IL-4, IL-10) and chemokines (MCP-1, CXCL4, CXCL10) driving disease progression, while adhesion molecules (ICAM-1, VCAM-1, VAP-1) promote leukocyte trafficking and cardiac inflammation. The balance between pro-inflammatory and regulatory responses determines disease outcomes, ranging from resolution with recovery to fulminant myocarditis or progression to dilated cardiomyopathy. Emerging therapeutic approaches targeting cytokines, chemokines, and adhesion molecules, along with established immunosuppressive treatments, underline the potential for modulating immune responses in myocarditis and, thereby, improving patient outcomes. Full article

CD99 is a membrane protein critical for various immunological functions, including T-cell activation, protein trafficking, cell apoptosis, and leukocyte movement. It is also highly expressed in certain malignant tumors, contributing to the development, invasion, immune evasion, and adaptation of tumor cells to stress stimuli, including drug resistance. CD99 is crucial at the intersection of normal biological processes and pathological conditions like cancer. While research indicates that CD99 may interact homotypically, there is evidence of some heterotypic ligands that align with its roles. The development of multiple anti-CD99 antibodies has shed light on its functions, particularly regarding interactions between tumor cells that overexpress CD99 and immune cells expressing the same protein within the microenvironment. Anti-CD99 antibodies effectively eliminate tumors and attract immune cells to the tumor area. Additionally, CD99 influences the expression of specific immune checkpoint molecules, such as CD47, paving the way for potential combinations of anti-CD99 with immune checkpoint inhibitors. This review explores CD99’s role in normal physiology and cancer biology, focusing on how monoclonal antibodies affect CD99 expression and activity, thereby influencing cancer cells’ interactions with their microenvironment. It summarizes key findings about how these changes impact cancer cell behavior and the effectiveness of treatments. Full article

Glioblastoma IDH wild type (GB), the most common malignant primary brain tumor, is characterized by rapid proliferation, extensive infiltration into surrounding brain tissue, and significant resistance to current therapies. Median survival is only 15 months despite extensive clinical efforts. The tumor microenvironment (TME) in GB is highly specialized, supporting the tumor’s aggressive behavior and its ability to evade conventional treatments. One critical component is the aberrant vascular network that complicates the delivery of chemotherapy across the blood–brain barrier. Antiangiogenic therapies emerged as a promising option but have shown limited efficacy in extending the survival of these patients. Comprehension of the complex vascular network of GB may be a key to overcoming the limitations of current therapies. Pericytes are gaining recognition within the context of the TME. These mural cells are essential for vascular integrity and may contribute to tumor progression and therapeutic resistance. Although their role has been evidenced in other tumors, they remain underexplored in GB. Pericytes are known to respond to tumor hypoxia and interact with vascular endothelia, influencing responses to DNA damage and antiangiogenic treatments. They actively regulate not only angiogenesis but also the different vasculogenic strategies for tumor neovascularization. Additionally, they affect leukocyte trafficking and tumor-associated macrophages. This review aims to integrate the various functions controlled by pericytes to favor deeper investigation into their actionable potential. Pericytes may represent a promising target for novel therapeutic strategies in order to improve patient outcomes. Full article

Introduction: The abscopal effect is a systemic immune response characterized by metastases regression at sites distant from the irradiated lesion. This systematic review aims to explore the immunological mechanisms of action underlying the abscopal effect and to investigate how hyperthermia (HT) can increase the chances of radiotherapy (RT) triggering systemic anti-tumor immune responses. Methods: This review is created in accordance with the PRISMA guidelines. Results and Conclusion: HT and RT have both complementary and synergistic immunological effects. Both methods trigger danger signal release, promoting cytokine and chemokine secretion, which increases T-cell infiltration and facilitates cell death. Both treatments upregulate extracellular tumor HSP70, which could amplify DAMP recognition by macrophages and DCs, leading to stronger tumor antigen presentation and CTL-mediated immune responses. Additionally, the combined increase in cell adhesion molecules (VCAM-1, ICAM-1, E-selectin, L-selectin) could enhance leukocyte adhesion to tumors, improving lymphocyte trafficking and boosting systemic anti-tumor effects. Lastly, HT causes vasodilation and improves blood flow, which might exacerbate those distant effects. We suggest the combination of local radiotherapy with fever-range whole-body hyperthermia to optimally enhance the chances of triggering the abscopal effect mediated by the immune system. Full article

Immune cell migration is required for the development of an effective and robust immune response. This elegant process is regulated by both cellular and environmental factors, with variables such as immune cell state, anatomical location, and disease state that govern differences in migration patterns. In all cases, a major factor is the expression of cell surface receptors and their cognate ligands. Rapid adaptation to environmental conditions partly depends on intrinsic cellular immune factors that affect a cell’s ability to adjust to new environment. In this review, we discuss both myeloid and lymphoid cells and outline key determinants that govern immune cell migration, including molecules required for immune cell adhesion, modes of migration, chemotaxis, and specific chemokine signaling. Furthermore, we summarize tumor-specific elements that contribute to immune cell trafficking to cancer, while also exploring microenvironment factors that can alter these cellular dynamics within the tumor in both a pro and antitumor fashion. Specifically, we highlight the importance of the secretome in these later aspects. This review considers a myriad of factors that impact immune cell trajectory in cancer. We aim to highlight the immunotherapeutic targets that can be harnessed to achieve controlled immune trafficking to and within tumors. Full article

CCR5 is among the most studied chemokine receptors due to its profound significance in human health and disease. The notion that CCR5 is a functionally redundant receptor was challenged through the demonstration of its unique protective role in the context of West Nile virus in both mice and humans. In the nearly two decades since this initial discovery, numerous studies have investigated the role of CCR5 in the context of other medically important neurotropic flaviviruses, most of which appear to support a broad neuroprotective role for this receptor, although how CCR5 exerts its protective effect has been remarkably varied. In this review, we summarize the mechanisms by which CCR5 controls neurotropic flaviviruses, as well as results from human studies evaluating a genetic link to CCR5, and propose unexplored areas of research that are needed to unveil even more exciting roles for this important receptor. Full article

Fabry disease (FD) is a recessive monogenic disease linked to chromosome X due to more than two hundred mutations in the alfa-galactosidase A (GLA) gene. Modifications of the GLA gene may cause the progressive accumulation of globotriaosylceramide (Gb3) and its deacylated form, globotriasylsphingosine (lyso-Gb3), in lysosomes of several types of cells of the heart, kidneys, skin, eyes, peripheral and central nervous system (not clearly and fully demonstrated), and gut with different and pleiotropic clinical symptoms. Among the main symptoms are acroparesthesias and pain crisis (involving the peripheral nervous system), hypohidrosis, abdominal pain, gut motility abnormalities (involving the autonomic system), and finally, cerebrovascular ischemic events due to macrovascular involvement (TIA and stroke) and lacunar strokes and white matter abnormalities due to a small vessel disease (SVS). Gb3 lysosomal accumulation causes cytoplasmatic disruption and subsequent cell death. Additional consequences of Gb3 deposits are inflammatory processes, abnormalities of leukocyte function, and impaired trafficking of some types of immune cells, including lymphocytes, monocytes, CD8+ cells, B cells, and dendritic cells. The involvement of inflammation in AFD pathogenesis conflicts with the reported poor correlation between CRP levels as an inflammation marker and clinical scores such as the Mainz Severity Score Index (MSSI). Also, some authors have suggested an autoimmune reaction is involved in the disease’s pathogenetic mechanism after the α-galactosidase A deficiency. Some studies have reported a high degree of neuronal apoptosis inhibiting protein as a critical anti-apoptotic mediator in children with Fabry disease compared to healthy controls. Notably, this apoptotic upregulation did not change after treatment with enzymatic replacement therapy (ERT), with a further upregulation of the apoptosis-inducing factor after ERT started. Gb3-accumulation has been reported to increase the degree of oxidative stress indexes and the production of reactive oxygen species (ROS). Lipids and proteins have been reported as oxidized and not functioning. Thus, neurological complications are linked to different pathogenetic molecular mechanisms. Progressive accumulation of Gb3 represents a possible pathogenetic event of peripheral nerve involvement. In contrast, central nervous system participation in the clinical setting of cerebrovascular ischemic events seems to be due to the epitheliopathy of Anderson–Fabry disease with lacunar lesions and white matter hyperintensities (WMHs). In this review manuscript, we revised molecular mechanisms of peripheral and central neurological complications of Anderson–Fabry Disease. The management of Fabry disease may be improved by the identification of biomarkers that reflect the clinical course, severity, and progression of the disease. Intensive research on biomarkers has been conducted over the years to detect novel markers that may potentially be used in clinical practice as a screening tool, in the context of the diagnostic process and as an indicator of response to treatment. Recent proteomic or metabolomic studies are in progress, investigating plasma proteome profiles in Fabry patients: these assessments may be useful to characterize the molecular pathology of the disease, improve the diagnostic process, and monitor the response to treatment. Full article