Periodic Reporting for period 4 - ANTILEAK (Development of antagonists of vascular leakage)
Período documentado: 2022-11-01 hasta 2024-04-30
The integrity of the vascular system is vital for maintaining proper organ function. In various diseases, such as systemic inflammation and cancer, this integrity is compromised, leading to increased fluid leakage or heightened traffic of inflammatory or cancer cells from the blood vessels into surrounding tissues. Such dysregulated fluid leakage results in tissue edema, impaired blood perfusion, and reduced tissue oxygenation, which can be life-threatening. Diseases associated with increased vascular leakage and impaired vascular barrier function represent a significant global health and economic burden, and current therapies are often insufficient.
Despite advances in understanding the regulation of endothelial cell-cell adhesions, which maintain the integrity of the blood vessels, the fundamental mechanisms leading to severe capillary leakage in disease remain incompletely understood. This knowledge gap highlights the urgent need to explore the molecular mechanisms that maintain vascular integrity and how they are regulated in disease contexts.
The overall objective of this project was to discover novel mechanisms that maintain vascular stability and to investigate how these mechanisms become dysregulated in inflammation, leading to leakage. Additionally, the project aimed to explore potential methods for repairing these dysfunctions. By focusing on candidate genes and using this new knowledge, the proposal seeked to develop innovative tools to target key molecules involved in vascular leakiness, ultimately contributing to the development of therapies that stabilize the vascular system and ensure proper organ function.
Despite advances in understanding the regulation of endothelial cell-cell adhesions, which maintain the integrity of the blood vessels, the fundamental mechanisms leading to severe capillary leakage in disease remain incompletely understood. This knowledge gap highlights the urgent need to explore the molecular mechanisms that maintain vascular integrity and how they are regulated in disease contexts.
The overall objective of this project was to discover novel mechanisms that maintain vascular stability and to investigate how these mechanisms become dysregulated in inflammation, leading to leakage. Additionally, the project aimed to explore potential methods for repairing these dysfunctions. By focusing on candidate genes and using this new knowledge, the proposal seeked to develop innovative tools to target key molecules involved in vascular leakiness, ultimately contributing to the development of therapies that stabilize the vascular system and ensure proper organ function.
We have uncovered novel cellular mechanisms that maintain vascular stability during systemic inflammation and cancer metastasis. Additionally, we have identified new regulators of endothelial permeability, highlighting potential targets and pathways for future studies aimed at developing vascular-stabilizing therapies.
Our research revealed that inflammation increases endothelial permeability via the adhesion receptor beta1-integrin. Inhibiting this pathway in a preclinical LPS-induced endotoxemia model with blocking antibodies significantly reduced vascular leakage and protected against endotoxemia-induced cardiac failure. We demonstrated that beta1-integrin enhances endothelial cell tension and forms specialized cell-matrix adhesions, particularly under inflammatory conditions. This discovery offers new insights into the regulation of vascular permeability, which could inform therapeutic strategies for systemic inflammation.
Additionally, we identified a novel function for the oncogenic Pim3 kinase in maintaining endothelial cell-cell adhesion integrity. We discovered that PIM kinase inhibitors, originally developed for cancer trials, impaired vascular barrier integrity, leading to vascular leakage and increased cancer metastasis. These findings may explain the lack of efficacy seen with PIM inhibitors as anti-cancer drugs in clinical trials. Moreover, this opens new avenues to investigate the mechanisms through which Pim3 maintains the vascular barrier, with potential translational impact.
We also discovered a new reactive capillary endothelial cell type in the lung alveolus that increases in number during cancer metastasis. These cells, while expressing angiogenic markers characteristic to tumor vasculature, also express vascular protective genes, suggesting a role in maintaining lung homeostasis under stress, such as metastasis or inflammation. Given the critical role of the lung vascular barrier in various inflammatory diseases, where its dysregulation can lead to alveolar leakage, our findings open new avenues for research on translationally relevant research areas.
We additionally established a pipeline for recombinant protein production, purification, and structural analysis, enabling us to investigate endothelial growth factors and their receptors at the atomic level. Our results uncover novel mechanisms of growth factor signaling in endothelial cell-cell junctions, involving interactions with two distinct receptor classes: growth factor receptors and cell adhesion receptors. This work demonstrates how growth factor oligomerization and conformational changes in cell adhesion receptors spatially pattern growth factor signaling in the endothelium. These findings provide fundamental insights into receptor tyrosine kinases signaling, offering critical understanding of how these receptors regulate cellular processes in the vasculature.
Our research revealed that inflammation increases endothelial permeability via the adhesion receptor beta1-integrin. Inhibiting this pathway in a preclinical LPS-induced endotoxemia model with blocking antibodies significantly reduced vascular leakage and protected against endotoxemia-induced cardiac failure. We demonstrated that beta1-integrin enhances endothelial cell tension and forms specialized cell-matrix adhesions, particularly under inflammatory conditions. This discovery offers new insights into the regulation of vascular permeability, which could inform therapeutic strategies for systemic inflammation.
Additionally, we identified a novel function for the oncogenic Pim3 kinase in maintaining endothelial cell-cell adhesion integrity. We discovered that PIM kinase inhibitors, originally developed for cancer trials, impaired vascular barrier integrity, leading to vascular leakage and increased cancer metastasis. These findings may explain the lack of efficacy seen with PIM inhibitors as anti-cancer drugs in clinical trials. Moreover, this opens new avenues to investigate the mechanisms through which Pim3 maintains the vascular barrier, with potential translational impact.
We also discovered a new reactive capillary endothelial cell type in the lung alveolus that increases in number during cancer metastasis. These cells, while expressing angiogenic markers characteristic to tumor vasculature, also express vascular protective genes, suggesting a role in maintaining lung homeostasis under stress, such as metastasis or inflammation. Given the critical role of the lung vascular barrier in various inflammatory diseases, where its dysregulation can lead to alveolar leakage, our findings open new avenues for research on translationally relevant research areas.
We additionally established a pipeline for recombinant protein production, purification, and structural analysis, enabling us to investigate endothelial growth factors and their receptors at the atomic level. Our results uncover novel mechanisms of growth factor signaling in endothelial cell-cell junctions, involving interactions with two distinct receptor classes: growth factor receptors and cell adhesion receptors. This work demonstrates how growth factor oligomerization and conformational changes in cell adhesion receptors spatially pattern growth factor signaling in the endothelium. These findings provide fundamental insights into receptor tyrosine kinases signaling, offering critical understanding of how these receptors regulate cellular processes in the vasculature.
Our results define novel mechanisms involved in the formation and maintenance of blood and lymphatic vascular systems and in the dysregulation of vascular barriers in disease. We have identified previously unknown molecules and cellular pathways that regulate the endothelial barrier. Our results show that molecules considered to be present in endothelial cell-matrix adhesions play a crucial role in determining cell-cell adhesion integrity, indicating signaling crosstalk between these cellular compartments. We found that such crosstalk is especially important to resist inflammation induced vascular leakage. Moreover, we identified novel endothelial cell identities in the organ-specific vascular barrier of the lungs, with potential role in maintenance of lung vascular homeostasis, and transcriptionally characterized these cells in mouse and human lungs. Additionally, we have uncovered fundamental new mechanisms of crosstalk between receptor tyrosine kinases (RTKs) and endothelial cell adhesion receptors, driven by oligomeric endothelial growth factors. These insights will inform strategies to target growth factor receptor signaling within the endothelium.