Cultured Lung Microvascular Endothelial Cells Research Articles

Serum IgA augments adhesiveness of cultured lung microvascular endothelial cells and suppresses angiogenesis

Immunoglobulin A (IgA) is important in local immunity and is also abundant in the blood. This study aimed to evaluate the effects of serum IgA on cultured lung microvascular endothelial cells (HMVEC-Ls), which are involved in the pathogenesis of inflammatory lung diseases. Serum IgA induced adhesion molecules and inflammatory cytokine production from HMVEC-Ls, and enhanced adhesion of peripheral blood mononuclear cells to HMVEC-Ls. In contrast, migration, proliferation, and tube formation of HMVEC-Ls were significantly suppressed by serum IgA. Experiments with siRNAs and western blotting revealed that two known IgA receptors, β1,4-galactosyltransferase 1 (b4GALT1) and asialoglycoprotein receptor 1 (ASGR1), and mitogen-activated protein kinase and nuclear factor-kappa B pathways were partly involved in serum IgA-induced cytokine production by HMVEC-Ls. Collectively, serum IgA enhanced cytokine production and adhesiveness of HMVEC-L, with b4GALT1 and ASGR1 partially being involved, and suppressed angiogenesis. Thus, serum IgA may be targeted to treat inflammatory lung diseases.

Endothelial to mesenchymal transition during neonatal hyperoxia-induced pulmonary hypertension.

Bronchopulmonary dysplasia (BPD), a chronic lung disease in premature infants, results from mechanical ventilation and hyperoxia, amongst other factors. Although most BPD survivors can be weaned from supplemental oxygen, many show evidence of cardiovascular sequelae in adulthood, including pulmonary hypertension and pulmonary vascular remodeling. Endothelial-mesenchymal transition (EndoMT) plays an important role in mediating vascular remodeling in idiopathic pulmonary arterial hypertension. Whether hyperoxic exposure, a known mediator of BPD in rodent models, causes EndoMT resulting in vascular remodeling and pulmonary hypertension remains unclear. We hypothesized that neonatal hyperoxic exposure causes EndoMT, leading to the development of pulmonary hypertension in adulthood. To test this hypothesis, newborn mice were exposed to hyperoxia and then allowed to recover in room air until adulthood. Neonatal hyperoxic exposure gradually caused pulmonary vascular and right ventricle remodeling as well as pulmonary hypertension. Male mice were more susceptible to developing pulmonary hypertension compared to female mice, when exposed to hyperoxia as newborns. Hyperoxic exposure induced EndoMT in mouse lungs as well as in cultured lung microvascular endothelial cells (LMVECs) isolated from neonatal mice and human fetal donors. This was augmented in cultured LMVECs from male donors compared to those from female donors. Using primary mouse LMVECs, hyperoxic exposure increased phosphorylation of both Smad2 and Smad3, but reduced Smad7 protein levels. Treatment with a selective TGF-β inhibitor SB431542 blocked hyperoxia-induced EndoMT in vitro. Altogether, we show that neonatal hyperoxic exposure caused vascular remodeling and pulmonary hypertension in adulthood. This was associated with increased EndoMT. These novel observations provide mechanisms underlying hyperoxia-induced vascular remodeling and potential approaches to prevent BPD-associated pulmonary hypertension by targeting EndoMT. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Alda-1 Protects Against Acrolein-Induced Acute Lung Injury and Endothelial Barrier Dysfunction.

Inhalation of acrolein, a highly reactive aldehyde, causes lung edema. The underlying mechanism is poorly understood and there is no effective treatment. In this study, we demonstrated that acrolein not only dose-dependently induced lung edema but also promoted LPS-induced acute lung injury. Importantly, acrolein-induced lung injury was prevented and rescued by Alda-1, an activator of mitochondrial aldehyde dehydrogenase 2. Acrolein also dose-dependently increased monolayer permeability, disrupted adherens junctions and focal adhesion complexes, and caused intercellular gap formation in primary cultured lung microvascular endothelial cells (LMVECs). These effects were attenuated by Alda-1 and the antioxidant N-acetylcysteine, but not by the NADPH inhibitor apocynin. Furthermore, acrolein inhibited AMP-activated protein kinase (AMPK) and increased mitochondrial reactive oxygen species levels in LMVECs-effects that were associated with impaired mitochondrial respiration. AMPK total protein levels were also reduced in lung tissue of mice and LMVECs exposed to acrolein. Activation of AMPK with 5-aminoimidazole-4-carboxamide-1-β-4-ribofuranoside blunted an acrolein-induced increase in endothelial monolayer permeability, but not mitochondrial oxidative stress or inhibition of mitochondrial respiration. Our results suggest that acrolein-induced mitochondrial dysfunction may not contribute to endothelial barrier dysfunction. We speculate that detoxification of acrolein by Alda-1 and activation of AMPK may be novel approaches to prevent and treat acrolein-associated acute lung injury, which may occur after smoke inhalation.

Hypoxia Results in Upregulation and De Novo Activation of Von Willebrand Factor Expression in Lung Endothelial Cells

Increased von Willebrand factor (VWF) levels in lungs are associated with diseases such as pulmonary hypertension. The objective of our study was to determine the mechanism of increased VWF levels in conditions, such as hypoxia, which contribute to pulmonary hypertension. We have previously reported generation of transgenic mice that express LacZ transgene under the regulation of lung- and brain-specific transcriptional regulatory elements of the VWF gene. Hypoxia exposure of these transgenic mice resulted in increased VWF and LacZ mRNA levels as well as redistribution of their expression from primarily larger vessels in the lungs to microvessels. Exposure of cultured lung microvascular endothelial cells to hypoxia demonstrated that VWF upregulation was accompanied by increased platelet binding. Transcription upregulation was mediated through inhibition of the repressor nuclear factor-IB association with the VWF promoter, and increased nuclear translocation of the transcription factor YY1 and association with its cognate binding site on the VWF gene. Knockdown of YY1 expression abolished the hypoxia-induced upregulation and reduced basal level of VWF. These analyses demonstrate that hypoxia induces a phenotypic shift, accompanied by modulation of nuclear factor-IB and YY1 activities, in microvascular endothelial cells of the lungs to support VWF promoter activation.

Endothelial cells on the proliferation and expression of intercellular adhesion molecule 1 and interleukin 8 of vascular smooth muscle cells

The aim of this study was to investigate the influence of activated endothelial cells on the proliferation and secretion of vascular smooth muscle cells (VSMCs). Cultured lung microvascular endothelial cells were treated with or without tumor necrosis factor alpha (TNF-α; 10 ng/mL) for 6 h, and the supernatant was collected and filtered. The supernatant with TNF-α was called fluid A, and that without TNF-α was called fluid B. VSMCs were cultured and divided into 3 groups with different media as follows: activated medium [fluid A and Dulbecco's modified Eagle medium (DMEM); activated group], inactivated medium (fluid B and DMEM; inactivated group), and DMEM only (control group) for 24 h. Intercellular adhesion molecule 1 (ICAM-1), interleukin (IL)-8, and IL-6 levels in the supernatant of VSMCs were measured with enzyme-linked immunosorbent assay 0 and 24 h after grouping. The proliferation of VSMCs was detected with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. ICAM-1 and IL-8 increased above baseline values in the 3 groups; the maximum increase occurred in activated medium. The optical densities in MTT assay of the activated, inactivated, and control groups was 1.35 ± 0.11, 1.01 ± 0.09, and 0.29 ± 0.01, respectively, which correlated positively with the initial IL-6 level in the supernatant of the VSMCs (r = 0.63, P < 0.05). TNF-α-activated endothelial cells promote VSMC proliferation and secretion of ICAM-1 and IL-8 by elevating IL-6 release.

002 Mechanism of Hypoxia Induction of VWF

002 Mechanism of Hypoxia Induction of VWF

P–185 - Transport mechanism of histidine by cultured lung microvascular endothelial cells in rats: Its enhancement by zinc.

P–185 - Transport mechanism of histidine by cultured lung microvascular endothelial cells in rats: Its enhancement by zinc.