Dysregulation of Neutrophil–Endothelial Communication in Sepsis: Mechanisms and Therapeutic Perspectives

Cells · 2026-03-25

Sepsis is a clinical syndrome defined as life-threatening organ dysfunction caused by a dysregulation in immune response to infection. Dysregulated neutrophil activity plays a critical role in sepsis-induced organ failure through interactions with the vascular endothelial cells during forward and reverse migration, resulting in vascular barrier disruption and increased neutrophil trafficking into vital organs. Therapeutic approaches for treating sepsis are mainly supportive. Due to limited clinical translation from rodent models, complexity of the pathophysiology, and most importantly, the heterogenous nature of sepsis, no significant therapeutics have been successfully developed to address the underlying immune dysregulation. In this review, we will discuss the important gap in knowledge on the fundamental mechanisms of neutrophil-endothelial interaction, the role that neutrophil forward and reverse migration plays in organ damage in sepsis, and how neutrophil and endothelial cell heterogeneity impact cell-cell communication. We will explore emerging methodologies, including novel omic and microphysiological systems, to study the underlying mechanism of neutrophil-endothelial interaction and neutrophil forward migration/reverse migration. Finally, we will review potential therapeutic targets modulating neutrophil-endothelial interaction and the challenges of translating them from bench to bedside.

Prioritizing FDA approved therapeutics for treating sepsis phenotypes: A network modeling approach based on neutrophil proteomics

Frontiers in Immunology · 2025-08-14 · 1 citations

Introduction: Sepsis is characterized by life-threatening organ dysfunction caused by dysregulated host response to infection. A key contributor is the disruption of neutrophil-endothelial interactions. Despite extensive research, there are no FDA-approved therapies that directly target altered neutrophil function in sepsis. Methods: We previously identified three functionally distinct neutrophil phenotypes in sepsis patients: Hyperimmune, Hypoimmune, and Hybrid, using clinical profiling, organ-on-chip models, and proteomics. In this study, we applied bioinformatics tools to elucidate the molecular pathways and druggable targets associated with each phenotype. Differentially expressed proteins were identified using ExpressAnalyst, while pathway enrichment and modeling were performed via Metascape and KEGG-based analyses. DrugBank and the Broad Institute Drug Repurposing Hub were queried to identify FDA-approved therapeutics. STRING and Cytoscape were used to build protein-protein interaction networks and prioritize hub targets. Results: In our study, the Hyperimmune and Hybrid neutrophil phenotypes had similar numbers of upregulated proteins, while the Hypoimmune and Hybrid neutrophil phenotypes had approximately the same numbers of downregulated proteins. Functional enrichment analysis highlighted several biological processes and pathways that impacted adhesion/migration patterns, such as calcium transport and neutrophil degranulation. Neutrophil pathway analysis highlighted nine differentially expressed proteins that were directly implicated in known neutrophil processes related to sepsis, such as leukocyte transendothelial migration. These findings were leveraged to identify FDA-approved therapeutics that could be repurposed to target proteins within each phenotype highlighting the impact in normalizing altered neutrophil-related responses such as adhesion, migration and pro-inflammatory mediator release. Finally, a protein-protein interaction network was employed to prioritize these target proteins within each phenotype using network analysis and identified three distinct drug targets across phenotypes that could modulate the neutrophil response in sepsis: VTN in the Hybrid phenotype, TRPV2 in the Hypoimmune phenotype and H2AC21 in the Hyperimmune phenotype. Discussion: Our integrative approach highlights phenotype-specific drug targets and FDA-approved candidates to modulate dysfunctional neutrophil responses in sepsis. This strategy supports a precision medicine framework for repurposing existing drugs based on neutrophil functional phenotyping.

Distinct Neutrophil Phenotypes in Sepsis Patients and Associations With Disease Severity, Comorbidities, and Neutrophil Extracellular Traps (NETs)

2024-04-30

The critical role of neutrophil-endothelial cell interactions in sepsis: new synergistic approaches employing organ-on-chip, omics, immune cell phenotyping and in silico modeling to identify new therapeutics

Frontiers in Cellular and Infection Microbiology · 2024-01-08 · 18 citations

Sepsis is a global health concern accounting for more than 1 in 5 deaths worldwide. Sepsis is now defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis can develop from bacterial (gram negative or gram positive), fungal or viral (such as COVID) infections. However, therapeutics developed in animal models and traditional in vitro sepsis models have had little success in clinical trials, as these models have failed to fully replicate the underlying pathophysiology and heterogeneity of the disease. The current understanding is that the host response to sepsis is highly diverse among patients, and this heterogeneity impacts immune function and response to infection. Phenotyping immune function and classifying sepsis patients into specific endotypes is needed to develop a personalized treatment approach. Neutrophil-endothelium interactions play a critical role in sepsis progression, and increased neutrophil influx and endothelial barrier disruption have important roles in the early course of organ damage. Understanding the mechanism of neutrophil-endothelium interactions and how immune function impacts this interaction can help us better manage the disease and lead to the discovery of new diagnostic and prognosis tools for effective treatments. In this review, we will discuss the latest research exploring how in silico modeling of a synergistic combination of new organ-on-chip models incorporating human cells/tissue, omics analysis and clinical data from sepsis patients will allow us to identify relevant signaling pathways and characterize specific immune phenotypes in patients. Emerging technologies such as machine learning can then be leveraged to identify druggable therapeutic targets and relate them to immune phenotypes and underlying infectious agents. This synergistic approach can lead to the development of new therapeutics and the identification of FDA approved drugs that can be repurposed for the treatment of sepsis.

Prioritizing FDA approved therapeutics for treating sepsis phenotypes: A network modeling approach based on neutrophil proteomics

2024-11-18

Sepsis is characterized by life-threatening organ dysfunction caused by dysregulated host response to infection. An underlying cause of sepsis is dysregulation of neutrophil-endothelial interactions. To date, therapeutic approaches are supportive, and there are no effective drugs that target immune dysregulation and alter neutrophil-endothelium function. In our prior investigation, three distinct neutrophil functional phenotypes (i.e., Hyperimmune, Hypoimmune and Hybrid) were identified in sepsis patients through a comprehensive analysis encompassing clinical, organ-on-chip and proteomic assessments. In this study, we utilized bioinformatics to elucidate cellular processes impacting each neutrophil phenotype. These findings were leveraged to identify potential FDA-approved therapeutics that could be repurposed to target proteins within each phenotype highlighting the impact in normalizing altered neutrophil-related responses such as adhesion and migration. A protein-protein interaction network was employed to prioritize these target proteins. Finally, we identify several FDA approved therapeutics for treating sepsis including a (pre)clinical trial therapeutic targeting VTN in the Hybrid phenotype, a therapeutic targeting TRPV2 in the Hypoimmune phenotype and a (pre)clinical trial therapeutic targeting H2AC21 in the Hyperimmune phenotype. Thus, we not only identified critical cellular processes impacting each neutrophil phenotype but also reveal those protein targets that could be prioritized for future validation in the treatment of sepsis.

Distinct functional neutrophil phenotypes in sepsis patients correlate with disease severity

Frontiers in Immunology · 2024-03-08 · 15 citations

Purpose: Sepsis is a clinical syndrome defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis is a highly heterogeneous syndrome with distinct phenotypes that impact immune function and response to infection. To develop targeted therapeutics, immunophenotyping is needed to identify distinct functional phenotypes of immune cells. In this study, we utilized our Organ-on-Chip assay to categorize sepsis patients into distinct phenotypes using patient data, neutrophil functional analysis, and proteomics. Methods: Following informed consent, neutrophils and plasma were isolated from sepsis patients in the Temple University Hospital ICU (n=45) and healthy control donors (n=7). Human lung microvascular endothelial cells (HLMVEC) were cultured in the Organ-on-Chip and treated with buffer or cytomix ((TNF/IL-1β/IFNγ). Neutrophil adhesion and migration across HLMVEC in the Organ-on-Chip were used to categorize functional neutrophil phenotypes. Quantitative label-free global proteomics was performed on neutrophils to identify differentially expressed proteins. Plasma levels of sepsis biomarkers and neutrophil extracellular traps (NETs) were determined by ELISA. Results: neutrophil adhesion and migration patterns. The phenotypes were classified as: Hyperimmune characterized by enhanced neutrophil adhesion and migration, Hypoimmune that was unresponsive to stimulation, and Hybrid with increased adhesion but blunted migration. These functional phenotypes were associated with distinct proteomic signatures and differentiated sepsis patients by important clinical parameters related to disease severity. The Hyperimmune group demonstrated higher oxygen requirements, increased mechanical ventilation, and longer ICU length of stay compared to the Hypoimmune and Hybrid groups. Patients with the Hyperimmune neutrophil phenotype had significantly increased circulating neutrophils and elevated plasma levels NETs. Conclusion: Neutrophils and NETs play a critical role in vascular barrier dysfunction in sepsis and elevated NETs may be a key biomarker identifying the Hyperimmune group. Our results establish significant associations between specific neutrophil functional phenotypes and disease severity and identify important functional parameters in sepsis pathophysiology that may provide a new approach to classify sepsis patients for specific therapeutic interventions.

Distinct Neutrophil Phenotypes in Sepsis Patients and Associations With Clinical Outcomes and Sources of Sepsis

2023-05-01

1002 Bacterial amyloid curli/eDNA complexes induce NETosis in lupus patients positive for anti-dsDNA

Genetics · 2022-12-01

<h3></h3> Infections are a major contributor to lupus disease. Uropathogenic E. coli (UPEC) is responsible for the majority of urinary tract infections in both healthy individuals and lupus patients. We have previously demonstrated that bacterial amyloid curli complexes of curli/DNA, produced by E.coli, can accelerate disease in mouse models of lupus. Moreover we have extended these findings to human lupus and demonstrate that curli/DNA complexes mimic lupus autoantigens and that patients with chronic bacteriuria and high levels of anti-curli/DNA have higher levels of anti-dsDNA, more flares and a proinflammatory profile. These findings suggest that curli/DNA complexes and subclinical chronic urinary bacterial infections might be a trigger and a propagator of autoimmunity via activation of the innate and adaptive immune system. Based on our previous results, we hypothesize that exposure to UPEC containing curli/eDNA complexes could also activate neutrophils, the first responders to bacterial infections, and specifically via generation of neutrophil extracellular traps (NETs), a fundamental mechanism to clear bacteria and a recently appreciated pathogenic mechanism in lupus. Neutrophil extracellular traps (NETs) are part of the innate immune system and are pathogenic in SLE. We therefore investigated 56 lupus patients who met at least 4 SLICC criteria. Results were compared to 20 age, sex, and race matched healthy controls. We found that curli/eDNA induced more NETs in SLE PMNs compared to healthy controls. In SLE, patients who were high inducers of NETs triggered by curli/eDNA complexes were also a high inducer of NETs triggered by LPS and PMA. Interestingly, patients who were anti- dsDNA positive made more NETs in response to curli/eDNA complexes. Moreover, we found patients who are anti-dsDNA positive responded highly to curli/eDNA complexes and LPS. We did not observe this in patients who were anti-dsDNA negative. Mechanistically, we found that curli/eDNA induce NETs via NADPH oxidase. Finally, we found patients who had bacteriuria had a higher amount of NET production in response to curli/eDNA complexes and PMA compared to patients with no bacteriuria. We conclude 1) that lupus PMNs are in a chronic inflammatory state. And 2) that curli/eDNA complexes can activate neutrophils and exposure to UPECs could be a mechanism to sustain autoantigens in the form of neutrophil extracellular traps.

LEUKOCYTE PHENOTYPING IN SEPSIS USING OMICS, FUNCTIONAL ANALYSIS, AND IN SILICO MODELING

Shock · 2022-11-15 · 11 citations

ABSTRACT: Sepsis is a major health issue and a leading cause of death in hospitals globally. The treatment of sepsis is largely supportive, and there are no therapeutics available that target the underlying pathophysiology of the disease. The development of therapeutics for the treatment of sepsis is hindered by the heterogeneous nature of the disease. The presence of multiple, distinct immune phenotypes ranging from hyperimmune to immunosuppressed can significantly impact the host response to infection. Recently, omics, biomarkers, cell surface protein expression, and immune cell profiles have been used to classify immune status of sepsis patients. However, there has been limited studies of immune cell function during sepsis and even fewer correlating omics and biomarker alterations to functional consequences. In this review, we will discuss how the heterogeneity of sepsis and associated immune cell phenotypes result from changes in the omic makeup of cells and its correlation with leukocyte dysfunction. We will also discuss how emerging techniques such as in silico modeling and machine learning can help in phenotyping sepsis patients leading to precision medicine.

Omics of endothelial cell dysfunction in sepsis

Vascular Biology · 2022-05-01 · 22 citations

During sepsis, defined as life-threatening organ dysfunction due to dysregulated host response to infection, systemic inflammation activates endothelial cells and initiates a multifaceted cascade of pro-inflammatory signaling events, resulting in increased permeability and excessive recruitment of leukocytes. Vascular endothelial cells share many common properties but have organ-specific phenotypes with unique structure and function. Thus, therapies directed against endothelial cell phenotypes are needed to address organ-specific endothelial cell dysfunction. Omics allow for the study of expressed genes, proteins and/or metabolites in biological systems and provide insight on temporal and spatial evolution of signals during normal and diseased conditions. Proteomics quantifies protein expression, identifies protein–protein interactions and can reveal mechanistic changes in endothelial cells that would not be possible to study via reductionist methods alone. In this review, we provide an overview of how sepsis pathophysiology impacts omics with a focus on proteomic analysis of mouse endothelial cells during sepsis/inflammation and its relationship with the more clinically relevant omics of human endothelial cells. We discuss how omics has been used to define septic endotype signatures in different populations with a focus on proteomic analysis in organ-specific microvascular endothelial cells during sepsis or septic-like inflammation. We believe that studies defining septic endotypes based on proteomic expression in endothelial cell phenotypes are urgently needed to complement omic profiling of whole blood and better define sepsis subphenotypes. Lastly, we provide a discussion of how in silico modeling can be used to leverage the large volume of omics data to map response pathways in sepsis.