Origins and functional differences of blood endothelial cells

Protein Coronation-Induced Cancer Staging-Dependent Multilevel Cytotoxicity: An All-Humanized Study in Blood Vessel Organoids

The protein corona effect refers to the phenomenon wherein nanomaterials in the bloodstream are coated by serum proteins, yet how protein coronated nanomaterials interact with blood vessels and its toxicity implications remain poorly understood. In this study, we investigated protein corona-related vessel toxicity by using an all-humanized assay integrating blood vessel organoids and patient-derived serum. Initially, we screened various nanomaterials to discern how parameters including size, morphology, hydrophobicity, surface charge, and chirality-dependent protein corona difference influence their uptake by vessel organoids. For nanomaterials showing substantial differences in vessel uptake, their protein corona was analyzed by using label-free mass spectra. Our findings revealed the involvement of cancer staging-related cytoskeleton components in mediating preferential uptake by cells, including endothelial and mural cells. Additionally, a transcriptome study was conducted to elucidate the influence of nanomaterials. We confirmed that protein coronated nanomaterials provoke remodeling at both transcriptional and translational levels, impacting pathways such as PI3K-Akt/Hippo/Wnt, and membraneless organelle integrity, respectively. Our study further demonstrated that the remodeling potential of patient-derived protein coronated nanomaterials can be harnessed to synergize with antiangiogenesis therapeutics to improve the outcomes. We anticipate that this study will provide guidance for the safe use of nanomedicine in the future.

Missing the mark(ers): circulating endothelial cells and endothelial-derived extracellular vesicles are elevated in sickle cell disease plasma

Sickle cell disease (SCD) is a devastating hemolytic disease, marked by recurring bouts of painful vaso-occlusion, leading to tissue damage from ischemia/reperfusion pathophysiology. Central to this process are oxidative stress, endothelial cell activation, inflammation, and vascular dysfunction. The endothelium exhibits a pro-inflammatory, pro-coagulant, and enhanced permeability phenotype. We used flow cytometry to enumerate circulating endothelial cells (CECs, CD31+/CD45-/CD146+) in SCD and normal healthy control blood samples. Furthermore, we assessed CEC subtypes, including circulating endothelial progenitor cells (EPCs, CD31+/CD45-/CD146+/CD133+) and mature CECs (mCECs, CD31+/CD45-/CD146+/CD133-) with mCECs further subdivided into resting CECs (rCECs, VCAM-1-) and activated CECs (aCECs, VCAM-1+). As compared to healthy controls, total CECs and mCECs were elevated in SCD blood as compared to healthy control blood. Using the same markers along with size-based gating, we also used flow cytometry to enumerate endothelial-derived extracellular vesicles (EEVs) in plasma. We assessed EEV subtypes based on VCAM-1 expression, including activated EEVs (aEEVs, CD31+/CD45-/CD146+/CD133-/VCAM-1+) and resting EEVs (rEEVs, VCAM-1 negative), presumably derived from activated and resting endothelial cells, respectively. aEEVs were elevated in SCD patient plasma as compared to healthy controls. Importantly, in SCD patients, total EEVs and aEEVs were increased during self-reported pain crisis as compared to steady state. Plasma markers of endothelial cell activation including soluble E-selectin, P-selectin, VCAM-1, and ICAM-1 were elevated in SCD plasma. These data highlight strategies to detect SCD-related endothelial cell activation and demonstrate that endothelial cell activation markers may be useful to evaluate curative and non-curative therapies in SCD patients.

Transcriptional signatures of cortical structural changes in chronic insomnia disorder

Chronic insomnia disorder (CID) is a multidimensional disease that may influence various levels of brain organization, spanning the macroscopic structural connectome to microscopic gene expression. However, the connection between genomic variations and morphological alterations in CID remains unclear. Here, we investigated brain structural changes in CID patients at the whole-brain level and whether these link to transcriptional characteristics. Brain structural data from 104 CID patients and 102 matched healthy controls (HC) were acquired to examine cortical structural alterations using morphometric similarity (MS) analysis. Partial least squares (PLS) regression and transcriptome data from the Allen Human Brain Atlas were used to extract genomes related to MS changes. Gene-category enrichment analysis (GCEA) was used to identify potential molecular mechanisms behind the observed structural changes. We found that CID patients exhibited MS reductions in the parietal and limbic regions, along with enhancements in the temporal and frontal regions compared to HCs (pFDR < .05). Subsequently, PLS and GCEA revealed that these MS alterations were spatially correlated with a set of genes, especially those significantly correlated with excitatory and inhibitory neurons and chronic neuroinflammation. This neuroimaging-transcriptomic study bridges the gap between cortical structural changes and the molecular mechanisms in CID patients, providing novel insight into the pathophysiology of insomnia and targeted treatments.

Knockdown of the long noncoding RNA VSIG2-1:1 promotes the angiogenic ability of human pulmonary microvascular endothelial cells by activating the VEGF/PI3K/AKT pathway

BACKGROUND

Abnormal pulmonary vascular development poses significant clinical challenges for infants with bronchopulmonary dysplasia (BPD). Although numerous factors have been suggested to control the development of pulmonary blood vessels, the mechanisms underlying the role of long noncoding RNAs (lncRNAs) in this process remain unclear.

METHODS

A lncRNA array was used to measure the differential expression of lncRNAs in premature infants with and without BPD. The expression of lncRNA-VSIG2-1:1 in patients with BPD and hyperoxia-induced human pulmonary microvascular endothelial cells (HPMECs) was assessed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Fluorescence in situ hybridization (FISH) assay was performed to detect the subcellular localization of lncRNA-VSIG2-1:1. Pulmonary microvascular endothelial cells were stably transfected with adenoviral vectors to silence or overexpress lncRNA-VSIG2-1:1. The effects of lncRNA-VSIG2-1:1 on the proliferation, migration, and tube formation abilities of HPMECs subjected to hyperoxia were examined by performing Cell Counting Kit-8 (CCK-8), cell migration, and tubule formation assays. RNA sequencing (RNA-seq) was performed to determine the correlation between lncRNA-VSIG2-1:1 and phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT). The protein levels of vascular endothelial growth factor (VEGF), p-PI3K, PI3K, p-AKT, and AKT were determined using western blotting.

RESULTS

The expression of lncRNA-VSIG2-1:1 was upregulated in patients with BPD and hyperoxia-treated HPMECs. Inhibiting lncRNA-VSIG2-1:1 expression promoted the proliferation, migration, and tube-formation abilities of HPMECs, while significantly increasing VEGF, p-PI3K, and p-AKT levels.

CONCLUSION

Our findings reveal that the suppression of lncRNA-VSIG2-1:1 expression stimulates angiogenesis in vitro by inducing the initiation of the VEGF/PI3K/AKT signaling pathway. This observation may aid the development of novel therapeutic targets for treating BPD.

The effect of empagliflozin on circulating endothelial progenitor cells in patients with diabetes and stable coronary artery disease

BACKGROUND

Diabetes mellitus (DM) is associated with premature atherosclerotic disease, coronary artery disease (CAD) and chronic heart failure (HF), leading to increased morbidity and mortality. Sodium-Glucose Co-transporter 2 Inhibitors (SGLT2i) exhibit cardioprotective benefits beyond glucose lowering, reducing the risk of major cardiovascular events (MACE) and HF hospitalizations in patients with DM and CAD. Endothelial progenitor cells (EPCs) are bone marrow-derived cells involved in vascular repair, mobilized in response to vascular injury. The number and function of circulating EPCs (cEPCs) are negatively affected by cardiovascular risk factors, including DM. This study aimed to examine the response of cEPCs to SGLT2i treatment in DM patients with stable CAD.

METHODS

A prospective single-center study included patients with DM and stable CAD who were started on an SGLT2i (empagliflozin). Peripheral blood samples were collected at baseline, 1 month, and 3 months to evaluate cEPC levels and function by flow cytometry, immunohistochemistry and MTT assays.

RESULTS

Eighteen patients were included in the study (median age 73, (IQR 69, 77) years, 67% male). After 1 month of treatment with empagliflozin, there was no significant change in cEPCs level or function. However, following 3 months of treatment, a significant increase was observed both in cell levels (CD34(+)/VEGFR-2(+): from 0.49% (IQR 0.32, 0.64) to 1.58% (IQR 0.93, 1.82), p = 0.0006; CD133(+)/VEGFR-2(+): from 0.38% (IQR 0.27, 0.6) to 0.82% (IQR 0.7, 1.95), p = 0.0001) and in cell function (from 0.25 CFUs (IQR 0, 0.5) at baseline, to 2 CFUs (IQR 1, 2) at 3 months, p = 0.0012).

CONCLUSIONS

Empagliflozin treatment in patients with DM and stable CAD increases cEPC levels and function, implying a cardioprotective mechanism. These findings highlight the potential of SGLT2i in treating cardiovascular diseases, warranting further research to explore these effects and their long-term implications.

Anti-inflammatory Prowess of endothelial progenitor cells in the realm of biology and medicine

Endothelial inflammation plays a crucial role in vascular-related diseases, a leading cause of global mortality. Among various cellular players, endothelial progenitor cells (EPCs) emerge as non-differentiated endothelial cells circulating in the bloodstream. Recent evidence highlights the transformative role of EPCs in shifting from an inflammatory/immunosuppressive crisis to an anti-inflammatory/immunomodulatory response. Despite the importance of these functions, the regulatory mechanisms governing EPC activities and their physiological significance in vascular regenerative medicine remain elusive. Surprisingly, the current literature lacks a comprehensive review of EPCs' effects on inflammatory processes. This narrative review aims to fill this gap by exploring the cutting-edge role of EPCs against inflammation, from molecular intricacies to broader medical perspectives. By examining how EPCs modulate inflammatory responses, we aim to unravel their anti-inflammatory significance in vascular regenerative medicine, deepening insights into EPCs' molecular mechanisms and guiding future therapeutic strategies targeting vascular-related diseases.

The role of vasculature and angiogenesis in respiratory diseases

In European countries, nearly 10% of all hospital admissions are related to respiratory diseases, mainly chronic life-threatening diseases such as COPD, pulmonary hypertension, IPF or lung cancer. The contribution of blood vessels and angiogenesis to lung regeneration, remodeling and disease progression has been increasingly appreciated. The vascular supply of the lung shows the peculiarity of dual perfusion of the pulmonary circulation (vasa publica), which maintains a functional blood-gas barrier, and the bronchial circulation (vasa privata), which reveals a profiled capacity for angiogenesis (namely intussusceptive and sprouting angiogenesis) and alveolar-vascular remodeling by the recruitment of endothelial precursor cells. The aim of this review is to outline the importance of vascular remodeling and angiogenesis in a variety of non-neoplastic and neoplastic acute and chronic respiratory diseases such as lung infection, COPD, lung fibrosis, pulmonary hypertension and lung cancer.

Inflammatory risk contributes to post-COVID endothelial dysfunction through anti-ACKR1 autoantibody

Subclinical vascular impairment can be exacerbated in individuals who experience sustained inflammation after COVID-19 infection. Our study explores the prevalence and impact of autoantibodies on vascular dysfunction in healthy COVID-19 survivors, an area that remains inadequately investigated. Focusing on autoantibodies against the atypical chemokine receptor 1 (ACKR1), COVID-19 survivors demonstrated significantly elevated anti-ACKR1 autoantibodies, correlating with systemic cytokines, circulating damaged endothelial cells, and endothelial dysfunction. An independent cohort linked these autoantibodies to increased vascular disease outcomes during a median 6.7-yr follow-up. We analyzed a single-cell transcriptome atlas of endothelial cells from diverse mouse tissues, identifying enriched Ackr1 expressions in venous regions of the brain and soleus muscle vasculatures, which holds intriguing implications for tissue-specific venous thromboembolism manifestations reported in COVID-19. Functionally, purified immunoglobulin G (IgG) extracted from patient plasma did not trigger cell apoptosis or increase barrier permeability in human vein endothelial cells. Instead, plasma IgG enhanced antibody-dependent cellular cytotoxicity mediated by patient PBMCs, a phenomenon alleviated by blocking peptide or liposome ACKR1 recombinant protein. The blocking peptide uncovered that purified IgG from COVID-19 survivors possessed potential epitopes in the N-terminal extracellular domain of ACKR1, which effectively averted antibody-dependent cellular cytotoxicity. Our findings offer insights into therapeutic development to mitigate autoantibody reactivity in blood vessels in chronic inflammation.

CX3CL1 (Fractalkine)-CX3CR1 Axis in Inflammation-Induced Angiogenesis and Tumorigenesis

The chemotactic cytokine fractalkine (FKN, chemokine CX3CL1) has unique properties resulting from the combination of chemoattractants and adhesion molecules. The soluble form (sFKN) has chemotactic properties and strongly attracts T cells and monocytes. The membrane-bound form (mFKN) facilitates diapedesis and is responsible for cell-to-cell adhesion, especially by promoting the strong adhesion of leukocytes (monocytes) to activated endothelial cells with the subsequent formation of an extracellular matrix and angiogenesis. FKN signaling occurs via CX3CR1, which is the only known member of the CX3C chemokine receptor subfamily. Signaling within the FKN-CX3CR1 axis plays an important role in many processes related to inflammation and the immune response, which often occur simultaneously and overlap. FKN is strongly upregulated by hypoxia and/or inflammation-induced inflammatory cytokine release, and it may act locally as a key angiogenic factor in the highly hypoxic tumor microenvironment. The importance of the FKN/CX3CR1 signaling pathway in tumorigenesis and cancer metastasis results from its influence on cell adhesion, apoptosis, and cell migration. This review presents the role of the FKN signaling pathway in the context of angiogenesis in inflammation and cancer. The mechanisms determining the pro- or anti-tumor effects are presented, which are the cause of the seemingly contradictory results that create confusion regarding the therapeutic goals.

Human Cord Blood Endothelial Progenitor Cells and Pregnancy Complications (Preeclampsia, Gestational Diabetes Mellitus, and Fetal Growth Restriction)

Hemangioblasts give rise to endothelial progenitor cells (EPCs), which also express the cell surface markers CD133 and c-kit. They may differentiate into the outgrowth endothelial cells (OECs) that control neovascularization in the developing embryo. According to numerous studies, reduced levels of EPCs in circulation have been linked to human cardiovascular disorders. Furthermore, preeclampsia and senescence have been linked to levels of EPCs produced from cord blood. Uncertainties surround how preeclampsia affects the way EPCs function. It is reasonable to speculate that preeclampsia may have an impact on the function of fetal EPCs during the in utero period; however, the present literature suggests that maternal vasculopathies, including preeclampsia, damage fetal circulation. Additionally, the differentiation potential and general activity of EPCs may serve as an indicator of the health of the fetal vascular system as they promote neovascularization and repair during pregnancy. Thus, the purpose of this review is to compare-through the assessment of their quantity, differentiation potency, angiogenic activity, and senescence-the angiogenic function of fetal EPCs obtained from cord blood for normal and pregnancy problems (preeclampsia, gestational diabetes mellitus, and fetal growth restriction). This will shed light on the relationship between the angiogenic function of fetal EPCs and pregnancy complications, which could have an effect on the management of long-term health issues like metabolic and cardiovascular disorders in offspring with abnormal vasculature development.

Vascular organs-on-chip made with patient-derived endothelial cells: technologies to transform drug discovery and disease modeling

INTRODUCTION

Vascular diseases impart a tremendous burden on healthcare systems in the United States and across the world. Efforts to improve therapeutic interventions are hindered by limitations of current experimental models. The integration of patient-derived cells with organ-on-chip (OoC) technology is a promising avenue for preclinical drug screening that improves upon traditional cell culture and animal models.

AREAS COVERED

The authors review induced pluripotent stem cells (iPSC) and blood outgrowth endothelial cells (BOEC) as two sources for patient-derived endothelial cells (EC). They summarize several studies that leverage patient-derived EC and OoC for precision disease modeling of the vasculature, with a focus on applications for drug discovery. They also highlight the utility of patient-derived EC in other translational endeavors, including ex vivo organogenesis and multi-organ-chip integration.

EXPERT OPINION

Precision disease modeling continues to mature in the academic space, but end-use by pharmaceutical companies is currently limited. To fully realize their transformative potential, OoC systems must balance their complexity with their ability to integrate with the highly standardized and high-throughput experimentation required for drug discovery and development.