scholarly journals CD36 mediates albumin transcytosis by dermal but not lung microvascular endothelial cells: role in fatty acid delivery

2019 ◽  
Vol 316 (5) ◽  
pp. L740-L750 ◽  
Author(s):  
Hira Raheel ◽  
Siavash Ghaffari ◽  
Negar Khosraviani ◽  
Victoria Mintsopoulos ◽  
Derek Auyeung ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Fatty Acid ◽  
Scavenger Receptor ◽  
Subcutaneous Fat ◽  
Microvascular Endothelial Cells ◽  
Microvascular Endothelium ◽  
Knockout Mouse Model ◽  
Microvascular Endothelial ◽  
Total Body

In healthy blood vessels, albumin crosses the endothelium to leave the circulation by transcytosis. However, little is known about the regulation of albumin transcytosis or how it differs in different tissues; its physiological purpose is also unclear. Using total internal reflection fluorescence microscopy, we quantified transcytosis of albumin across primary human microvascular endothelial cells from both lung and skin. We then validated our in vitro findings using a tissue-specific knockout mouse model. We observed that albumin transcytosis was saturable in the skin but not the lung microvascular endothelial cells, implicating a receptor-mediated process. We identified the scavenger receptor CD36 as being both necessary and sufficient for albumin transcytosis across dermal microvascular endothelium, in contrast to the lung where macropinocytosis dominated. Mutations in the apical helical bundle of CD36 prevented albumin internalization by cells. Mice deficient in CD36 specifically in endothelial cells exhibited lower basal permeability to albumin and less basal tissue edema in the skin but not in the lung. Finally, these mice also exhibited a smaller subcutaneous fat layer despite having identical total body weights and circulating fatty acid levels as wild-type animals. In conclusion, CD36 mediates albumin transcytosis in the skin but not the lung. Albumin transcytosis may serve to regulate fatty acid delivery from the circulation to tissues.

Isolation and characterization of human and rat cardiac microvascular endothelial cells

1993 ◽  
Vol 264 (2) ◽  
pp. H639-H652 ◽  
Author(s):  
M. Nishida ◽  
W. W. Carley ◽  
M. E. Gerritsen ◽  
O. Ellingsen ◽  
R. A. Kelly ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Microvascular Endothelial Cells ◽  
Microvascular Endothelium ◽  
Adult Rat ◽  
Isolation And Characterization ◽  
Ventricular Tissue ◽  
Microvascular Endothelial ◽  
Cardiac Microvascular Endothelial Cells

Although reciprocal intercellular signaling may occur between endocardial or microvascular endothelium and cardiac myocytes, suitable in vitro models have not been well characterized. In this report, we describe the isolation and primary culture of cardiac microvascular endothelial cells (CMEC) from both adult rat and human ventricular tissue. Differential uptake of fluorescently labeled acetylated low-density lipoprotein (Ac-LDL) indicated that primary isolates of rat CMEC were quite homogeneous, unlike primary isolates of human ventricular tissue, which required cell sorting based on Ac-LDL uptake to create endothelial cell-enriched primary cultures. The endothelial phenotype of both primary isolates and postsort subcultured CMEC and their microvascular origin were determined by characteristic histochemical staining for a number of endothelial cell-specific markers, by the absence of cells with fibroblast or pericyte-specific cell surface antigens, and by rapid tube formation on purified basement membrane preparations. Importantly, [3H]-thymidine uptake was increased 2.3-fold in subconfluent rat microvascular endothelial cells 3 days after coculture with adult rat ventricular myocytes because of release of an endothelial cell mitogen(s) into the extracellular matrix, resulting in a 68% increase in cell number compared with CMEC in monoculture. Thus biologically relevant cell-to-cell interactions can be modeled with this in vitro system.

Ca(2+)-inhibitable adenylyl cyclase and pulmonary microvascular permeability

1997 ◽  
Vol 273 (1) ◽  
pp. L22-L30 ◽  
Author(s):  
P. M. Chetham ◽  
H. A. Guldemeester ◽  
N. Mons ◽  
G. H. Brough ◽  
J. P. Bridges ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Adenylyl Cyclase ◽  
Microvascular Permeability ◽  
Microvascular Endothelial Cells ◽  
Rat Lung ◽  
Microvascular Endothelium ◽  
Camp Content ◽  
Microvascular Endothelial ◽  
Vitro Model

Intracellular mechanisms responsible for endothelial cell disruption are unknown, although either elevated cytosolic Ca2+ ([Ca2+]i) or decreased adenosine 3',5'-cyclic monophosphate (cAMP) promotes permeability. Recent identification that Ca(2+)-inhibitable adenylyl cyclase establishes an inverse relationship between [Ca2+]i and cAMP in macrovascular endothelial cells provided a possible mechanism of development of permeability. However, these data utilized an in vitro model; lacking was evidence supporting 1) expression of Ca(2+)-inhibitable adenylyl cyclase in pulmonary microvascular endothelium and 2) Ca2+ inhibition of adenylyl cyclase and cAMP content as a paradigm for inflammatory mediator-induced permeability in the intact circulation. We therefore addressed these issues in microvascular endothelial cells derived from rat lung and in an isolated perfused rat lung preparation. Results demonstrate expression of a Ca(2+)-inhibitable adenylyl cyclase in microvascular endothelial cells. Furthermore, data suggest that Ca2+ inhibition of adenylyl cyclase is necessary for development of microvascular permeability in the intact circulation. We conclude Ca2+ inhibition of cAMP represents a critical step in genesis of microvascular permeability in the intact pulmonary circulation.

scholarly journals Pluripotent stem cell-derived epithelium misidentified as brain microvascular endothelium requires ETS factors to acquire vascular fate

2021 ◽  
Vol 118 (8) ◽  
pp. e2016950118 ◽  
Author(s):  
Tyler M. Lu ◽  
Sean Houghton ◽  
Tarig Magdeldin ◽  
José Gabriel Barcia Durán ◽  
Andrew P. Minotti ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Neurological Diseases ◽  
Microvascular Endothelial Cells ◽  
Brain Microvascular Endothelial Cells ◽  
Microvascular Endothelium ◽  
Functional Studies ◽  
Bona Fide ◽  
Microvascular Endothelial

Cells derived from pluripotent sources in vitro must resemble those found in vivo as closely as possible at both transcriptional and functional levels in order to be a useful tool for studying diseases and developing therapeutics. Recently, differentiation of human pluripotent stem cells (hPSCs) into brain microvascular endothelial cells (ECs) with blood–brain barrier (BBB)-like properties has been reported. These cells have since been used as a robust in vitro BBB model for drug delivery and mechanistic understanding of neurological diseases. However, the precise cellular identity of these induced brain microvascular endothelial cells (iBMECs) has not been well described. Employing a comprehensive transcriptomic metaanalysis of previously published hPSC-derived cells validated by physiological assays, we demonstrate that iBMECs lack functional attributes of ECs since they are deficient in vascular lineage genes while expressing clusters of genes related to the neuroectodermal epithelial lineage (Epi-iBMEC). Overexpression of key endothelial ETS transcription factors (ETV2, ERG, and FLI1) reprograms Epi-iBMECs into authentic endothelial cells that are congruent with bona fide endothelium at both transcriptomic as well as some functional levels. This approach could eventually be used to develop a robust human BBB model in vitro that resembles the human brain EC in vivo for functional studies and drug discovery.

scholarly journals Ultracytochemical characteristics of cultured goat brain microvascular endothelial cells [corrected]

1991 ◽  
Vol 39 (11) ◽  
pp. 1555-1563 ◽  
Author(s):  
A W Vorbrodt ◽  
R S Trowbridge
Keyword(s):  
Endothelial Cells ◽  
Plasma Membranes ◽  
Ricinus Communis ◽  
Enzymatic Activities ◽  
Gold Complex ◽  
Microvascular Endothelial Cells ◽  
Brain Microvascular Endothelial Cells ◽  
Microvascular Endothelium ◽  
Microvascular Endothelial

This ultrastructural study was undertaken to determine the localization of cytochemically demonstrable blood-brain barrier (BBB)-associated enzymatic activities and of some nonenzymatic constituents in goat [corrected] brain microvascular endothelial cells (ECs) growing in vitro. Positive reactions for alkaline phosphatase (AP), 5'-nucleotidase (5'N), transport ATPase (Na+,K(+)-ATPase), and adenosine diphosphatase (ADPase) were present on both apical and basolateral plasma membranes (PMs) of the ECs. The reaction for calcium-dependent ATPase (Ca(2+)-ATPase) was less intense and was restricted to basolateral PM and associated plasmalemmal pits. These cells also revealed an abundance of anionic sites labeled with cationic colloidal gold (CCG) and Ricinus communis agglutinin 120 (RCA)-binding sites, specific for beta-D-galactosyl residues, on the apical PM. The labeling of the apical PM with Ulex europaeus agglutinin (UEA)-gold complex, specific for alpha-L-fucosyl residues, was negligible. When compared with results of cytochemical examination of the ECs of goat [corrected] brain capillary in vivo, these observations indicate that although cells cultivated in vitro retain at confluence the enzymatic activities typical for BBB-type ECS, they lose their characteristic (polar) localization. This loss is interpreted as a reflection of lost functional polarity of the microvascular endothelium in vitro resulting from deprivation of the normal influence of the components of brain parenchyma.

Isolation and primary culture of rat cerebral microvascular endothelial cells for studying drug transport in vitro

1996 ◽  
Vol 36 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Nobuhiro Ichikawa ◽  
Kohji Naora ◽  
Hidenari Hirano ◽  
Michio Hashimoto ◽  
Sumio Masumura ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Primary Culture ◽  
Drug Transport ◽  
Microvascular Endothelial Cells ◽  
Microvascular Endothelial

scholarly journals A tumor-promoting role for soluble TβRIII in glioblastoma

2021 ◽  
Author(s):  
Isabel Burghardt ◽  
Judith Johanna Schroeder ◽  
Tobias Weiss ◽  
Dorothee Gramatzki ◽  
Michael Weller
Keyword(s):  
Endothelial Cells ◽  
Ex Vivo ◽  
Microvascular Endothelial Cells ◽  
Smad2 Phosphorylation ◽  
Cell Gene Expression ◽  
Microvascular Endothelial ◽  
Cell Gene ◽  
Mouse Glioma

Abstract Purpose Members of the transforming growth factor (TGF)-β superfamily play a key role in the regulation of the malignant phenotype of glioblastoma by promoting invasiveness, angiogenesis, immunosuppression, and maintaining stem cell-like properties. Betaglycan, a TGF-β coreceptor also known as TGF-β receptor III (TβRIII), interacts with members of the TGF-β superfamily and acts as membrane-associated or shed molecule. Shed, soluble TβRIII (sTβRIII) is produced upon ectodomain cleavage of the membrane-bound form. Elucidating the role of TβRIII may improve our understanding of TGF-β pathway activity in glioblastoma Methods Protein levels of TβRIII were determined by immunohistochemical analyses and ex vivo single-cell gene expression profiling of glioblastoma tissue respectively. In vitro, TβRIII levels were assessed investigating long-term glioma cell lines (LTCs), cultured human brain-derived microvascular endothelial cells (hCMECs), glioblastoma-derived microvascular endothelial cells, and glioma-initiating cell lines (GICs). The impact of TβRIII on TGF-β signaling was investigated, and results were validated in a xenograft mouse glioma model Results Immunohistochemistry and ex vivo single-cell gene expression profiling of glioblastoma tissue showed that TβRIII was expressed in the tumor tissue, predominantly in the vascular compartment. We confirmed this pattern of TβRIII expression in vitro. Specifically, we detected sTβRIII in glioblastoma-derived microvascular endothelial cells. STβRIII facilitated TGF-β-induced Smad2 phosphorylation in vitro and overexpression of sTβRIII in a xenograft mouse glioma model led to increased levels of Smad2 phosphorylation, increased tumor volume, and decreased survival Conclusions These data shed light on the potential tumor-promoting role of extracellular shed TβRIII which may be released by glioblastoma endothelium with high sTβRIII levels.

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