The metalloproteinase ADAM8 promotes leukocyte recruitment in vitro and in acute lung inflammation

Alveolar leukocyte recruitment is a hallmark of acute lung inflammation and involves transmigration of leukocytes through endothelial and epithelial layers. The disintegrin and metalloproteinase (ADAM) 8 is expressed on human isolated leukocytic cells and can be further upregulated on cultured endothelial and epithelial cells by proinflammatory cytokines. By shRNA-mediated knockdown we show that leukocytic ADAM8 is required on monocytic THP-1 cells for chemokine-induced chemotaxis as well as transendothelial and transepithelial migration. Furthermore, ADAM8 promotes αL-integrin upregulation and THP-1 cell adhesion to endothelial cells. On endothelial cells ADAM8 enhances transendothelial migration and increases cytokine-induced permeability. On epithelial cells the protease facilitates migration in a wound closure assay but does not affect transepithelial leukocyte migration. Blood leukocytes and bone marrow-derived macrophages (BMDM) from ADAM8-deficient mice show suppressed chemotactic response. Intranasal application of LPS to mice is accompanied with ADAM8 upregulation in the lung. In this model of acute lung inflammation ADAM8-deficient mice are protected against leukocyte infiltration. Finally, transfer experiments of BMDM in mice indicate that ADAM8 exerts a promigratory function predominantly on leukocytes. Our study provides in vitro and in vivo evidence that ADAM8 on leukocytes holds a proinflammatory function in acute lung inflammation by promoting alveolar leukocyte recruitment.

Download Full-text

Combined In Vitro and In Vivo Approaches to Propose a Putative Adverse Outcome Pathway for Acute Lung Inflammation Induced by Nanoparticles: A Study on Carbon Dots

Nanomaterials ◽

10.3390/nano11010180 ◽

2021 ◽

Vol 11 (1) ◽

pp. 180

Author(s):

Maud Weiss ◽

Jiahui Fan ◽

Mickaël Claudel ◽

Luc Lebeau ◽

Françoise Pons ◽

...

Keyword(s):

Carbon Dots ◽

Lung Inflammation ◽

Adverse Outcome ◽

Cellular Responses ◽

Target Cells ◽

Inflammasome Activation ◽

Adverse Outcome Pathway ◽

Acute Lung Inflammation

With the growth of nanotechnologies, concerns raised regarding the potential adverse effects of nanoparticles (NPs), especially on the respiratory tract. Adverse outcome pathways (AOP) have become recently the subject of intensive studies in order to get a better understanding of the mechanisms of NP toxicity, and hence hopefully predict the health risks associated with NP exposure. Herein, we propose a putative AOP for the lung toxicity of NPs using emerging nanomaterials called carbon dots (CDs), and in vivo and in vitro experimental approaches. We first investigated the effect of a single administration of CDs on mouse airways. We showed that CDs induce an acute lung inflammation and identified airway macrophages as target cells of CDs. Then, we studied the cellular responses induced by CDs in an in vitro model of macrophages. We observed that CDs are internalized by these cells (molecular initial event) and induce a series of key events, including loss of lysosomal integrity and mitochondrial disruption (organelle responses), as well as oxidative stress, inflammasome activation, inflammatory cytokine upregulation and macrophage death (cellular responses). All these effects triggering lung inflammation as tissular response may lead to acute lung injury.

Download Full-text

The Crucial Role of PPARγ-Egr-1-Pro-Inflammatory Mediators Axis in IgG Immune Complex-Induced Acute Lung Injury

Frontiers in Immunology ◽

10.3389/fimmu.2021.634889 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chunguang Yan ◽

Jing Chen ◽

Yue Ding ◽

Zetian Zhou ◽

Bingyu Li ◽

...

Keyword(s):

Transcription Factor ◽

Acute Lung Injury ◽

Lung Injury ◽

Immune Complex ◽

Inflammatory Mediators ◽

Lung Inflammation ◽

Acute Lung Inflammation ◽

Pparγ Agonist

BackgroundThe ligand-activated transcription factor peroxisome proliferator-activated receptor (PPAR) γ plays crucial roles in diverse biological processes including cellular metabolism, differentiation, development, and immune response. However, during IgG immune complex (IgG-IC)-induced acute lung inflammation, its expression and function in the pulmonary tissue remains unknown.ObjectivesThe study is designed to determine the effect of PPARγ on IgG-IC-triggered acute lung inflammation, and the underlying mechanisms, which might provide theoretical basis for therapy of acute lung inflammation.SettingDepartment of Pathogenic Biology and Immunology, Medical School of Southeast UniversitySubjectsMice with down-regulated/up-regulated PPARγ activity or down-regulation of Early growth response protein 1 (Egr-1) expression, and the corresponding controls.InterventionsAcute lung inflammation is induced in the mice by airway deposition of IgG-IC. Activation of PPARγ is achieved by using its agonist Rosiglitazone or adenoviral vectors that could mediate overexpression of PPARγ. PPARγ activity is suppressed by application of its antagonist GW9662 or shRNA. Egr-1 expression is down-regulated by using the gene specific shRNA.Measures and Main ResultsWe find that during IgG-IC-induced acute lung inflammation, PPARγ expression at both RNA and protein levels is repressed, which is consistent with the results obtained from macrophages treated with IgG-IC. Furthermore, both in vivo and in vitro data show that PPARγ activation reduces IgG-IC-mediated pro-inflammatory mediators’ production, thereby alleviating lung injury. In terms of mechanism, we observe that the generation of Egr-1 elicited by IgG-IC is inhibited by PPARγ. As an important transcription factor, Egr-1 transcription is substantially increased by IgG-IC in both in vivo and in vitro studies, leading to augmented protein expression, thus amplifying IgG-IC-triggered expressions of inflammatory factors via association with their promoters.ConclusionDuring IgG-IC-stimulated acute lung inflammation, PPARγ activation can relieve the inflammatory response by suppressing the expression of its downstream target Egr-1 that directly binds to the promoter regions of several inflammation-associated genes. Therefore, regulation of PPARγ-Egr-1-pro-inflammatory mediators axis by PPARγ agonist Rosiglitazone may represent a novel strategy for blockade of acute lung injury.

Download Full-text

Disruption of endothelial Pfkfb3 ameliorates diet-induced murine insulin resistance

Journal of Endocrinology ◽

10.1530/joe-20-0524 ◽

2021 ◽

Author(s):

Qiuhua Yang ◽

Jiean Xu ◽

Qian Ma ◽

Zhiping Liu ◽

Yaqi Zhou ◽

...

Keyword(s):

Insulin Resistance ◽

Endothelial Cells ◽

High Fat Diet ◽

Inflammatory Responses ◽

Critical Role ◽

Endothelial Inflammation ◽

Glucose Clearance ◽

Deficient Mice

Overnutrition-induced endothelial inflammation plays a crucial role in high fat diet (HFD)-induced insulin resistance in animals. Endothelial glycolysis plays a critical role in endothelial inflammation and proliferation, but its role in diet-induced endothelial inflammation and subsequent insulin resistance has not been elucidated. PFKFB3 is a critical glycolytic regulator, and its increased expression has been observed in adipose vascular endothelium of C57BL/6J mice fed with HFD in vivo, and in palmitate (PA)-treated primary human adipose microvascular endothelial cells (HAMECs) in vitro. We generated mice with Pfkfb3 deficiency selective for endothelial cells to examine the effect of endothelial Pfkfb3 in endothelial inflammation in metabolic organs and in the development of HFD-induced insulin resistance. EC Pfkfb3-deficient mice exhibited mitigated HFD-induced insulin resistance, including decreased body weight and fat mass, improved glucose clearance and insulin sensitivity, and alleviated adiposity and hepatic steatosis. Mechanistically, cultured PFKFB3 knockdown HAMECs showed decreased NF-κB activation induced by PA, and consequent suppressed adhesion molecule expression and monocyte adhesion. Taken together, these results demonstrate that increased endothelial PFKFB3 expression promotes diet-induced inflammatory responses and subsequent insulin resistance, suggesting that endothelial metabolic alteration plays an important role in the development of insulin resistance.

Download Full-text

Human Cytomegalovirus Cell Tropism and Host Cell Receptors

Vaccines ◽

10.3390/vaccines7030070 ◽

2019 ◽

Vol 7 (3) ◽

pp. 70 ◽

Cited By ~ 11

Author(s):

Gerna ◽

Kabanova ◽

Lilleri

Keyword(s):

Endothelial Cells ◽

Endothelial Cell ◽

Epithelial Cells ◽

Human Cytomegalovirus ◽

Current Data ◽

Immunosuppressed Patient ◽

Cell Tropism ◽

Virus Envelope

In the 1970s–1980s, a striking increase in the number of disseminated human cytomegalovirus (HCMV) infections occurred in immunosuppressed patient populations. Autopsy findings documented the in vivo disseminated infection (besides fibroblasts) of epithelial cells, endothelial cells, and polymorphonuclear leukocytes. As a result, multiple diagnostic assays, such as quantification of HCMV antigenemia (pp65), viremia (infectious virus), and DNAemia (HCMV DNA) in patient blood, were developed. In vitro experiments showed that only low passage or endothelial cell-passaged clinical isolates, and not laboratory-adapted strains, could reproduce both HCMV leuko- and endothelial cell-tropism, which were found through genetic analysis to require the three viral genes UL128, UL130, and UL131 of the HCMV UL128 locus (UL128L). Products of this locus, together with gH/gL, were shown to form the gH/gL/pUL128L pentamer complex (PC) required for infection of epithelial cells/endothelial cells, whereas gH/gL and gO form the gH/gL/gO trimer complex (TC) required for infection of all cell types. In 2016, following previous work, a receptor for the TC that mediates entry into fibroblasts was identified as PDGFRα, while in 2018, a receptor for the PC that mediates entry into endothelial/epithelial cells was identified as neuropilin2 (Nrp2). Furthermore, the olfactory receptor family member OR14I1 was recently identified as a possible additional receptor for the PC in epithelial cells. Thus, current data support two models of viral entry: (i) in fibroblasts, following interaction of PDGFRα with TC, the latter activates gB to fuse the virus envelope with the cell membrane, whereas (ii) in epithelial cells/endothelial cells, interaction of Nrp2 (and OR14I1) with PC promotes endocytosis of virus particles, followed by gB activation by gH/gL/gO (or gH/gL) and final low-pH entry into the cell.

Download Full-text

Role of surface complexed iron in oxidant generation and lung inflammation induced by silicates

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1992.263.5.l511 ◽

1992 ◽

Vol 263 (5) ◽

pp. L511-L518 ◽

Cited By ~ 17

Author(s):

A. J. Ghio ◽

T. P. Kennedy ◽

A. R. Whorton ◽

A. L. Crumbliss ◽

G. E. Hatch ◽

...

Keyword(s):

Respiratory Burst ◽

Lung Inflammation ◽

Important Determinant ◽

Surface Complexation ◽

Oxidative Degradation ◽

Transition Metal Ions ◽

Leukotriene B4 ◽

Acute Lung Inflammation

Inhalation of silicates induces a variety of lung diseases in humans. The molecular mechanism(s) by which these dusts cause disease is not known. Because several naturally occurring mineral oxides have large amounts of transition metal ions on their surfaces, we tested the hypothesis that surface complexation of iron may be an important determinant of their ability to induce disease. Silica, crocidolite, kaolinite, and talc complexed considerable concentrations of Fe3+ onto their surfaces from both in vitro and in vivo sources. The potential biological importance of iron complexation was assessed by examining the relationship between surface [Fe3+] and the ability of silicates to mediate oxidative degradation of deoxyribose in vitro, induce a respiratory burst and elicit leukotriene B4 (LTB4) release by alveolar macrophages (AM) in vitro, and cause acute alveolitis after intratracheal insufflation. For these studies, three varieties of silicate dusts were used: iron-loaded, wetted (unmodified), and deferoxamine-treated to remove Fe3+. The ability of silicates to catalyze oxidant generation in an ascorbate/H2O2 system in vitro, to trigger respiratory burst activity and LTB4 release by AM, and to induce acute lung inflammation in the rat all increased with surface complexed Fe3+. The results of these studies suggest that surface complexation of iron may be an important determinant in the pathogenesis of disease after silicate exposure.

Download Full-text

Depletion of pulmonary intravascular macrophages inhibits acute lung inflammation

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00003.2003 ◽

2004 ◽

Vol 286 (2) ◽

pp. L363-L372 ◽

Cited By ~ 31

Author(s):

Baljit Singh ◽

Jacqueline W. Pearce ◽

Lakshman N. Gamage ◽

Kyathanahalli Janardhan ◽

Sarah Caldwell

Keyword(s):

Lung Inflammation ◽

Acute Inflammation ◽

Inflammatory Cells ◽

Acute Lung Inflammation ◽

Tnf Α ◽

Highly Sensitive ◽

In Vitro Exposure ◽

Pulmonary Intravascular Macrophages

Pulmonary intravascular macrophages (PIMs) are present in ruminants and horses. These species are highly sensitive to acute lung inflammation compared with non-PIM-containing species such as rats and humans. There is evidence that rats and humans may also recruit PIMs under certain conditions. We investigated precise contributions of PIMs to acute lung inflammation in a calf model. First, PIMs were recognized with a combination of in vivo phagocytic tracer Monastral blue and postembedding immunohistology with anti-CD68 monoclonal antibody. Second, gadolinium chloride depleted PIMs within 48 h of treatment ( P < 0.05). Finally, PIMs contain TNF-α, and their depletion reduces cells positive for IL-8 ( P < 0.05) and TNF-α ( P < 0.05) and histopathological signs of acute lung inflammation in calves infected with Mannheimia hemolytica. The majority of IL-8-positive inflammatory cells in lung septa of infected calves were platelets. Platelets from normal cattle contained preformed IL-8 that was released upon in vitro exposure to thrombin ( P < 0.05). These novel data show that PIMs, as the source of TNF-α, promote recruitment of inflammatory cells including IL-8-containing platelets to stimulate acute inflammation and pathology in lungs. These data may also be relevant to humans due to our ability to recruit PIMs.

Download Full-text

BMP9 regulates endoglin-dependent chemokine responses in endothelial cells

Blood ◽

10.1182/blood-2012-07-440784 ◽

2012 ◽

Vol 120 (20) ◽

pp. 4263-4273 ◽

Cited By ~ 44

Author(s):

Kira Young ◽

Barbara Conley ◽

Diana Romero ◽

Eric Tweedie ◽

Christine O'Neill ◽

...

Keyword(s):

Endothelial Cells ◽

Target Genes ◽

Endothelial Cell Migration ◽

Quantitative Mass Spectrometry ◽

Chemokine Cxcl12 ◽

Vessel Maturation ◽

Rna Knockdown ◽

Deficient Mice

Abstract BMP9 signaling has been implicated in hereditary hemorrhagic telangiectasia (HHT) and vascular remodeling, acting via the HHT target genes, endoglin and ALK1. This study sought to identify endothelial BMP9-regulated proteins that could affect the HHT phenotype. Gene ontology analysis of cDNA microarray data obtained after BMP9 treatment of primary human endothelial cells indicated regulation of chemokine, adhesion, and inflammation pathways. These responses included the up-regulation of the chemokine CXCL12/SDF1 and down-regulation of its receptor CXCR4. Quantitative mass spectrometry identified additional secreted proteins, including the chemokine CXCL10/IP10. RNA knockdown of endoglin and ALK1 impaired SDF1/CXCR4 regulation by BMP9. Because of the association of SDF1 with ischemia, we analyzed its expression under hypoxia in response to BMP9 in vitro, and during the response to hindlimb ischemia, in endoglin-deficient mice. BMP9 and hypoxia were additive inducers of SDF1 expression. Moreover, the data suggest that endoglin deficiency impaired SDF1 expression in endothelial cells in vivo. Our data implicate BMP9 in regulation of the SDF1/CXCR4 chemokine axis in endothelial cells and point to a role for BMP9 signaling via endoglin in a switch from an SDF1-responsive autocrine phenotype to an SDF1 nonresponsive paracrine state that represses endothelial cell migration and may promote vessel maturation.

Download Full-text

Abstract 376: Downregulation of Endogenous Apelinergic Axis Mediates Endothelial and Organismal Senescence

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.376 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Rahul Rai ◽

Asish K Ghosh ◽

Layton H Smith ◽

Douglas E Vaughan

Keyword(s):

Endothelial Cells ◽

Replicative Senescence ◽

Cell Types ◽

Ang Ii ◽

Systematic Assessment ◽

Multiple Cell ◽

Deficient Mice

Background: Apelinergic signaling is a recently discovered GPCR mediated pathway. Endothelial cells are the main source of endogenous apelin (apln) while apelin receptor (aplnr) is present on multiple cell types. Since the role of endogenous apelinergic pathway within the context of senescence is largely unknown, we ask if levels of apln- aplnr vary with aging. We also investigate the effects of downregulated apln- aplnr on cellular and organismal aging. Approach and Results: To assess variations in endogenous apln- aplnr with aging, we compared their levels in 1 month (young) and 1 year old (old) WT mice. We noticed significant downregulation of apln- aplnr with chronological senescence in multiple tissues. Expression of apelin was also reduced with replicative senescence of endothelial cells. L-NAME administration, a model of stress induced senescence, also repressed aortic and cardiac apln. To address the mechanism involved in downregulation of apln- aplnr, we administered young wild type mice with Ang II. After a week of Ang II, there was significant downregulation of aortic apln and aplnr. Ang II and TGF-β also repressed apln and aplnr in vitro . Next we investigated the effects of downregulated apln on endothelial cells. In response to shRNA mediated apelin knockdown, cells exhibited slower proliferation and upregulated senescence associated markers. We observed similar results when endothelial aplnr was blocked with an antagonist, ML221. In addition, apln and aplnr deficient mice also exhibited features of cardiovascular aging, including ventricular hypertrophy and lower EF. Importantly, aplnr deficient mice at eight months of age were also hypertensive. Conclusion: We provide a systematic assessment of senescence associated variation in levels of apln- aplnr. We demonstrate the role of Ang II- TGF-β axis in downregulating apln- aplnr during chronological and stress induced senescence in vivo and in vitro . We propose a novel model of Ang II- TGF-β induced senescence. Where in, with aging Ang II and TGF-β repress endogenous apln- aplnr. Downregulation of endogenous apln- aplnr axis decreases beneficial “youthful” effects of apelin, resulting in endothelial dysfunction and accelerated organismal aging.

Download Full-text

Human induced pluripotent stem cell-derived neuroectodermal epithelial cells mistaken for blood-brain barrier-forming endothelial cells

10.1101/699173 ◽

2019 ◽

Cited By ~ 6

Author(s):

Tyler M. Lu ◽

David Redmond ◽

Tarig Magdeldin ◽

Duc-Huy T. Nguyen ◽

Amanda Snead ◽

...

Keyword(s):

Endothelial Cells ◽

Epithelial Cells ◽

Blood Brain Barrier ◽

Neurological Diseases ◽

Brain Barrier ◽

Brain Functions ◽

Blood Brain ◽

Induced Pluripotent

AbstractBrain microvascular endothelial cells (BMECs) possess unique properties underlying the blood-brain-barrier (BBB), that are crucial for homeostatic brain functions and interactions with the immune system. Modulation of BBB function is essential for treatment of neurological diseases and effective tumor targeting. Studies to-date have been hampered by the lack of physiological models using cultivated human BMECs that sustain BBB properties. Recently, differentiation of induced pluripotent stem cells (iPSCs) into cells with BBB-like properties has been reported, providing a robust in vitro model for drug screening and mechanistic understanding of neurological diseases. However, the precise identity of these iBMECs remains unclear. Employing single-cell RNA sequencing, bioinformatic analysis and immunofluorescence for several pathways, transcription factors (TFs), and surface markers, we examined the molecular and functional properties of iBMECs differentiated either in the absence or presence of retinoic acid. We found that iBMECs lack both endothelial-lineage genes and ETS TFs that are essential for the establishment and maintenance of EC identity. Moreover, iBMECs fail to respond to angiogenic stimuli and form lumenized vessels in vivo. We demonstrate that human iBMECs are not barrier-forming ECs but rather EpCAM+ neuroectodermal epithelial cells (NE-EpiCs) that form tight junctions resembling those present in BBB-forming BMECs. Finally, overexpression of ETS TFs (ETV2, FLI1, and ERG) reprograms NE-EpiCs to become more like the BBB-forming ECs. Thus, although directed differentiation of human iBMECs primarily gives rise to epithelial cells, overexpression of several ETS TFs can divert them toward a vascular BBB in vitro.

Download Full-text

CD112 Regulates Angiogenesis and T Cell Entry into the Spleen

Cells ◽

10.3390/cells10010169 ◽

2021 ◽

Vol 10 (1) ◽

pp. 169

Author(s):

Erica Russo ◽

Peter Runge ◽

Neda Haghayegh Jahromi ◽

Heidi Naboth ◽

Angela Landtwing ◽

...

Keyword(s):

Endothelial Cells ◽

Cell Migration ◽

Endothelial Cell ◽

T Cell ◽

Cell Entry ◽

Endothelial Cell Migration ◽

Leukocyte Trafficking ◽

Deficient Mice

Junctional adhesion proteins play important roles in controlling angiogenesis, vascular permeability and leukocyte trafficking. CD112 (nectin-2) belongs to the immunoglobulin superfamily and was shown to engage in homophilic and heterophilic interactions with a variety of binding partners expressed on endothelial cells and on leukocytes. Recent in vitro studies suggested that CD112 regulates human endothelial cell migration and proliferation as well as transendothelial migration of leukocytes. However, so far, the role of CD112 in endothelial cell biology and in leukocyte trafficking has not been elucidated in vivo. We found CD112 to be expressed by lymphatic and blood endothelial cells in different murine tissues. In CD112-deficient mice, the blood vessel coverage in the retina and spleen was significantly enhanced. In functional in vitro studies, a blockade of CD112 modulated endothelial cell migration and significantly enhanced endothelial tube formation. An antibody-based blockade of CD112 also significantly reduced T cell transmigration across endothelial monolayers in vitro. Moreover, T cell homing to the spleen was significantly reduced in CD112-deficient mice. Overall, our results identify CD112 as a regulator of angiogenic processes in vivo and demonstrate a novel role for CD112 in T cell entry into the spleen.

Download Full-text