The Markers of Endothelial Activation

Rationale: Arterial inflammation manifested as atherosclerosis is the leading cause of mortality worldwide. Genome-wide association studies have identified a prominent role of HDAC (histone deacetylase)-9 in atherosclerosis and its clinical complications including stroke and myocardial infarction. Objective: To determine the mechanisms linking HDAC9 to these vascular pathologies and explore its therapeutic potential for atheroprotection. Methods and Results: We studied the effects of Hdac9 on features of plaque vulnerability using bone marrow reconstitution experiments and pharmacological targeting with a small molecule inhibitor in hyperlipidemic mice. We further used 2-photon and intravital microscopy to study endothelial activation and leukocyte-endothelial interactions. We show that hematopoietic Hdac9 deficiency reduces lesional macrophage content while increasing fibrous cap thickness thus conferring plaque stability. We demonstrate that HDAC9 binds to IKK (inhibitory kappa B kinase)-α and β, resulting in their deacetylation and subsequent activation, which drives inflammatory responses in both macrophages and endothelial cells. Pharmacological inhibition of HDAC9 with the class IIa HDAC inhibitor TMP195 attenuates lesion formation by reducing endothelial activation and leukocyte recruitment along with limiting proinflammatory responses in macrophages. Transcriptional profiling using RNA sequencing revealed that TMP195 downregulates key inflammatory pathways consistent with inhibitory effects on IKKβ. TMP195 mitigates the progression of established lesions and inhibits the infiltration of inflammatory cells. Moreover, TMP195 diminishes features of plaque vulnerability and thereby enhances plaque stability in advanced lesions. Ex vivo treatment of monocytes from patients with established atherosclerosis reduced the production of inflammatory cytokines including IL (interleukin)-1β and IL-6. Conclusions: Our findings identify HDAC9 as a regulator of atherosclerotic plaque stability and IKK activation thus providing a mechanistic explanation for the prominence of HDAC9 as a vascular risk locus in genome-wide association studies. Its therapeutic inhibition may provide a potent lever to alleviate vascular inflammation. Graphical Abstract: A graphical abstract is available for this article.

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Successful weight loss reduces endothelial activation in individuals with severe obesity participating in a multimodal weight loss program

Obesity Research & Clinical Practice ◽

10.1016/j.orcp.2021.03.013 ◽

2021 ◽

Author(s):

Sabine J.M. Sag ◽

Christina Strack ◽

Judith Zeller ◽

Margareta Mohr ◽

Thomas Loew ◽

...

Keyword(s):

Weight Loss ◽

Severe Obesity ◽

Endothelial Activation ◽

Weight Loss Program ◽

Successful Weight Loss

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TNFα secreted by glioma associated macrophages promotes endothelial activation and resistance against anti-angiogenic therapy

Acta Neuropathologica Communications ◽

10.1186/s40478-021-01163-0 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Qingxia Wei ◽

Olivia Singh ◽

Can Ekinci ◽

Jaspreet Gill ◽

Mira Li ◽

...

Keyword(s):

Critical Role ◽

Gene Expression Signature ◽

Endothelial Activation ◽

Tumor Vascularization ◽

Angiogenic Therapy ◽

Mouse Glioma ◽

Novel Therapeutic ◽

Tumor Area

AbstractOne of the most prominent features of glioblastoma (GBM) is hyper-vascularization. Bone marrow-derived macrophages are actively recruited to the tumor and referred to as glioma-associated macrophages (GAMs) which are thought to provide a critical role in tumor neo-vascularization. However, the mechanisms by which GAMs regulate endothelial cells (ECs) in the process of tumor vascularization and response to anti-angiogenic therapy (AATx) is not well-understood. Here we show that GBM cells secrete IL-8 and CCL2 which stimulate GAMs to produce TNFα. Subsequently, TNFα induces a distinct gene expression signature of activated ECs including VCAM-1, ICAM-1, CXCL5, and CXCL10. Inhibition of TNFα blocks GAM-induced EC activation both in vitro and in vivo and improve survival in mouse glioma models. Importantly we show that high TNFα expression predicts worse response to Bevacizumab in GBM patients. We further demonstrated in mouse model that treatment with B20.4.1.1, the mouse analog of Bevacizumab, increased macrophage recruitment to the tumor area and correlated with upregulated TNFα expression in GAMs and increased EC activation, which may be responsible for the failure of AATx in GBMs. These results suggest TNFα is a novel therapeutic that may reverse resistance to AATx. Future clinical studies should be aimed at inhibiting TNFα as a concurrent therapy in GBMs.

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Endothelial activation and dysfunction in COVID-19: from basic mechanisms to potential therapeutic approaches

Signal Transduction and Targeted Therapy ◽

10.1038/s41392-020-00454-7 ◽

2020 ◽

Vol 5 (1) ◽

Author(s):

Yuefei Jin ◽

Wangquan Ji ◽

Haiyan Yang ◽

Shuaiyin Chen ◽

Weiguo Zhang ◽

...

Keyword(s):

Molecular Mechanisms ◽

Endothelial Activation ◽

World Health ◽

Therapeutic Approaches ◽

Inflammatory Reactions ◽

Angiotensin Converting Enzyme 2 ◽

Therapeutic Implications ◽

Endothelial Inflammation ◽

The World ◽

Health Organization

AbstractOn 12 March 2020, the outbreak of coronavirus disease 2019 (COVID-19) was declared a pandemic by the World Health Organization. As of 4 August 2020, more than 18 million confirmed infections had been reported globally. Most patients have mild symptoms, but some patients develop respiratory failure which is the leading cause of death among COVID-19 patients. Endothelial cells with high levels of angiotensin-converting enzyme 2 expression are major participants and regulators of inflammatory reactions and coagulation. Accumulating evidence suggests that endothelial activation and dysfunction participate in COVID-19 pathogenesis by altering the integrity of vessel barrier, promoting pro-coagulative state, inducing endothelial inflammation, and even mediating leukocyte infiltration. This review describes the proposed cellular and molecular mechanisms of endothelial activation and dysfunction during COVID-19 emphasizing the principal mediators and therapeutic implications.

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Early bilirubinemia after allogeneic stem cell transplantation—an endothelial complication

Bone Marrow Transplantation ◽

10.1038/s41409-020-01186-6 ◽

2021 ◽

Author(s):

Hao Dai ◽

Olaf Penack ◽

Aleksandar Radujkovic ◽

David Schult ◽

Joshua Majer-Lauterbach ◽

...

Keyword(s):

Stem Cell ◽

Stem Cell Transplantation ◽

Cell Transplantation ◽

Allogeneic Stem Cell Transplantation ◽

Serum Levels ◽

Endothelial Activation ◽

Stress Index ◽

Clinical Correlations ◽

Angiopoietin 2 ◽

The Impact

AbstractHyperbilirubinemia occurs frequently after allogeneic stem cell transplantation. Causes include primary liver damage and endothelial complications as major contributors. Here, we have investigated the impact of early bilirubinemia (EB) on posttransplant outcomes. Maximum total bilirubin levels (days 0–28) were categorized using maximally selected log rank statistics to identify a cut off for the endpoint non-relapse mortality (NRM) in a training cohort of 873 patients. EB above this cut off was correlated with NRM and overall survival (OS) and with pre- and posttransplant Angiopoietin-2, interleukin (IL)18, CXCL8 and suppressor of tumorigenicity-2 (ST2) serum levels, and the endothelial activation and stress index (EASIX). Clinical correlations were validated in a sample of 388 patients transplanted in an independent institution. The EB cut off was determined at 3.6 mg/dL (61.6 µM). EB predicted OS (HR 1.60, 95% CI 1.21–2.12, p < 0.001), and NRM (CSHR 2.14; 1.28–3.56, p = 0.004), also independent of typical endothelial complications such as veno-occlusive disease, refractory acute graft-versus-host disease, or transplant-associated microangiopathy. However, EB correlated with high Angiopoietin-2, EASIX-pre and EASIX-day 0, as well as increased levels of posttransplant CXCL8, IL18, and ST2. In summary, EB indicates a poor prognosis. The association of EB with endothelial biomarkers suggests an endothelial pathomechanism also for this posttransplant complication.

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