scholarly journals Extracellular vesicle release and uptake by the liver under normo- and hyperlipidemia

2021 ◽  
Author(s):  
Krisztina Németh ◽  
Zoltán Varga ◽  
Dorina Lenzinger ◽  
Tamás Visnovitz ◽  
Anna Koncz ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Kupffer Cells ◽  
Liver Cell ◽  
High Fat Diet ◽  
Cell Types ◽  
Extracellular Vesicle ◽  
High Fat ◽  
Liver Sinusoidal Endothelial Cells ◽  
Sinusoidal Endothelial Cells

AbstractLiver plays a central role in elimination of circulating extracellular vesicles (EVs), and it also significantly contributes to EV release. However, the involvement of the different liver cell populations remains unknown. Here, we investigated EV uptake and release both in normolipemia and hyperlipidemia. C57BL/6 mice were kept on high fat diet for 20–30 weeks before circulating EV profiles were determined. In addition, control mice were intravenously injected with 99mTc-HYNIC-Duramycin labeled EVs, and an hour later, biodistribution was analyzed by SPECT/CT. In vitro, isolated liver cell types were tested for EV release and uptake with/without prior fatty acid treatment. We detected an elevated circulating EV number after the high fat diet. To clarify the differential involvement of liver cell types, we carried out in vitro experiments. We found an increased release of EVs by primary hepatocytes at concentrations of fatty acids comparable to what is characteristic for hyperlipidemia. When investigating EV biodistribution with 99mTc-labeled EVs, we detected EV accumulation primarily in the liver upon intravenous injection of mice with medium (326.3 ± 19.8 nm) and small EVs (130.5 ± 5.8 nm). In vitro, we found that medium and small EVs were preferentially taken up by Kupffer cells, and liver sinusoidal endothelial cells, respectively. Finally, we demonstrated that in hyperlipidemia, there was a decreased EV uptake both by Kupffer cells and liver sinusoidal endothelial cells. Our data suggest that hyperlipidema increases the release and reduces the uptake of EVs by liver cells. We also provide evidence for a size-dependent differential EV uptake by the different cell types of the liver. The EV radiolabeling protocol using 99mTc-Duramycin may provide a fast and simple labeling approach for SPECT/CT imaging of EVs biodistribution.

scholarly journals LSEC Fenestrae Are Preserved Despite Pro-inflammatory Phenotype of Liver Sinusoidal Endothelial Cells in Mice on High Fat Diet

2019 ◽  
Vol 10 ◽  
Author(s):  
Edyta Kus ◽  
Patrycja Kaczara ◽  
Izabela Czyzynska-Cichon ◽  
Karolina Szafranska ◽  
Bartlomiej Zapotoczny ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
High Fat Diet ◽  
High Fat ◽  
Liver Sinusoidal Endothelial Cells ◽  
Sinusoidal Endothelial Cells ◽  
Inflammatory Phenotype

scholarly journals The uptake and metabolism of chylomicron-remnant lipids by rat liver parenchymal and non-parenchymal cells in vitro

1985 ◽  
Vol 232 (2) ◽  
pp. 395-401 ◽  
Author(s):  
P M Lippiello ◽  
P J Sisson ◽  
M Waite
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Liver Cell ◽  
Cholesterol Ester ◽  
Cell Types ◽  
Chylomicron Remnant ◽  
Parenchymal Cells ◽  
Uptake And Metabolism

The uptake and metabolism of chylomicron-remnant lipids by individual liver cell types was examined by incubating remnants with monolayer cultures of hepatocytes, Kupffer cells, and endothelial cells from rat liver. Remnants were prepared in vitro from radiolabelled mesenteric-lymph chylomicra, utilizing either purified lipoprotein lipase from bovine milk, or plasma isolated from heparinized rats. The resulting particles contained [3H]phosphatidylcholine and cholesterol, and [14C]oleate in the acylglycerol, phospholipid, fatty-acid and cholesterol-ester fractions. The capacities of the three cell types for uptake of both [3H]lipids and [14C]lipids were determined to be, on a per-cell basis, in the order: Kupffer greater than hepatocytes greater than endothelial. The relative proportions of [3H]phospholipid and total [3H]cholesterol taken up by hepatocytes and non-parenchymal cells remained constant with time. The uptake of [14C]oleoyl lipids by all three cell types was slightly greater than that of the total [3H]cholesterol and [3H]phospholipid components. There was evidence of cholesterol-ester hydrolysis and turnover of [14C]oleate in the phospholipid fraction in hepatocytes and Kupffer cells, but not endothelial cells, over the first 2 h. With both remnant preparations, these observations indicate that significant differences exist between the three major liver cell types with respect to the uptake and metabolism of remnant lipid components.

scholarly journals Single-cell transcriptome analysis reveals cellular heterogeneity in the ascending aortas of normal and high-fat diet-fed mice

2021 ◽  
Vol 53 (9) ◽  
pp. 1379-1389
Author(s):  
Hao Kan ◽  
Ka Zhang ◽  
Aiqin Mao ◽  
Li Geng ◽  
Mengru Gao ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Single Cell ◽  
High Fat Diet ◽  
Cell Types ◽  
Ascending Aorta ◽  
Normal Diet ◽  
Cellular Heterogeneity ◽  
Cellular Composition ◽  
High Fat ◽  
Aortic Diseases

AbstractThe aorta contains numerous cell types that contribute to vascular inflammation and thus the progression of aortic diseases. However, the heterogeneity and cellular composition of the ascending aorta in the setting of a high-fat diet (HFD) have not been fully assessed. We performed single-cell RNA sequencing on ascending aortas from mice fed a normal diet and mice fed a HFD. Unsupervised cluster analysis of the transcriptional profiles from 24,001 aortic cells identified 27 clusters representing 10 cell types: endothelial cells (ECs), fibroblasts, vascular smooth muscle cells (SMCs), immune cells (B cells, T cells, macrophages, and dendritic cells), mesothelial cells, pericytes, and neural cells. After HFD intake, subpopulations of endothelial cells with lipid transport and angiogenesis capacity and extensive expression of contractile genes were defined. In the HFD group, three major SMC subpopulations showed increased expression of extracellular matrix-degradation genes, and a synthetic SMC subcluster was proportionally increased. This increase was accompanied by upregulation of proinflammatory genes. Under HFD conditions, aortic-resident macrophage numbers were increased, and blood-derived macrophages showed the strongest expression of proinflammatory cytokines. Our study elucidates the nature and range of the cellular composition of the ascending aorta and increases understanding of the development and progression of aortic inflammatory disease.

scholarly journals Transcriptome and proteome profiling reveal complementary scavenger and immune features of rat liver sinusoidal endothelial cells and liver macrophages

2020 ◽  
Author(s):  
Sabin Bhandari ◽  
Ruomei Li ◽  
Jaione Simón-Santamaría ◽  
Peter McCourt ◽  
Steinar Daae Johansen ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Antigen Processing ◽  
Constitutive Expression ◽  
Cell Types ◽  
The Body ◽  
Male Rats ◽  
Molecular Profile ◽  
Immune Functions ◽  
Liver Sinusoidal Endothelial Cells ◽  
Sinusoidal Endothelial Cells

Abstract Background: Liver sinusoidal endothelial cells (LSECs) and Kupffer cells (KCs; liver resident macrophages) form the body´s most effective scavenger cell system for the removal of harmful blood-borne substances, ranging from modified self-proteins to pathogens and xenobiotics. Controversies in the literature regarding the LSEC phenotype pose a challenge when determining distinct functionalities of KCs and LSECs. This may be due to overlapping functions of the two cells, insufficient purification and/or identification of the cells, rapid dedifferentiation of LSECs in vitro, or species differences. We therefore characterized and quantitatively compared expressed gene products of freshly isolated, highly pure LSECs (fenestrated SE-1/FcgRIIb2+) and KCs (CD11b/c+) from Sprague Dawley, Crl:CD(SD), male rats using high throughput mRNA-sequencing and label-free proteomics.Results: We observed a robust correlation between the proteomes and transcriptomes of the two cell types. Integrative analysis of the global molecular profile demonstrated the immunological aspects of LSECs. The constitutive expression of several immune genes and corresponding proteins of LSECs bore some resemblance with the expression in macrophages. LSECs and KCs both expressed high levels of scavenger receptors (SR) and C-type lectins. Equivalent expression of SR-A1 (Msr1), mannose receptor (Mrc1), SR-B1 (Scarb1), and SR-B3 (Scarb2) suggested functional similarity between the two cell types, while functional distinction between the cells was evidenced by LSEC-specific expression of the SRs stabilin-1 (Stab1) and stabilin-2 (Stab2), and the C-type lectins LSECtin (Clec4g) and DC-SIGNR (Clec4m). Many immune regulatory factors were differentially expressed in LSECs and KCs, with one cell predominantly expressing a specific cytokine/chemokine and the other cell the cognate receptor, illustrating the complex cytokine milieu of the sinusoids. Both cells expressed genes and proteins involved in antigen processing and presentation, and lymphocyte co-stimulation. Conclusions: Our findings support complementary and partly overlapping scavenging and immune functions of LSECs and KCs. This highlights the importance of including LSECs in studies of liver immunity, and liver clearance and toxicity of large molecule drugs and nano-formulations.

scholarly journals Mineralocorticoid and Estrogen Receptors in Endothelial Cells Coordinately Regulate Microvascular Function in Obese Female Mice

Hypertension ◽  
2021 ◽  
Author(s):  
Lauren A. Biwer ◽  
Brigett V. Carvajal ◽  
Qing Lu ◽  
Joshua J. Man ◽  
Iris Z. Jaffe
Keyword(s):  
Endothelial Cells ◽  
High Fat Diet ◽  
Ex Vivo ◽  
Microvascular Dysfunction ◽  
Estrogen Receptor Α ◽  
No Synthase ◽  
Wild Type ◽  
High Fat ◽  
Obese Female

Obesity impairs endothelial-mediated vasodilation, the earliest step in vascular disease and a contributor to hypertension. We previously demonstrated that endothelial cell MR (mineralocorticoid receptor) deletion prevents obesity-induced microvascular dysfunction in females by increasing nitric oxide (NO)-mediated vasodilation. ERα (Estrogen receptor α) can oppose MR function, therefore, we hypothesized that ERα mediates the benefits of endothelial MR deficiency. Females lacking endothelial MR or wild-type littermates were fed control or high-fat diet for 20 weeks to cause obesity. MR deletion improved mesenteric artery endothelial-dependent vasodilation in obese females, and ex vivo ERα inhibition negated this protective effect. Endothelial MR deletion resulted in significantly more ERα mRNA and protein. In vitro, estrogen increased endothelial NO synthase phosphorylation, and this was inhibited by aldosterone and dependent on MR. Both proteins coimmunoprecipitated with striatin and a mimetic peptide that disrupts ERα-striatin binding also decreased MR-striatin interaction. Finally, removing endothelial MR in obese females restored endothelial function by increasing the NO component of vasodilation. Combined deletion of endothelial ERα negated the benefit of endothelial MR deletion. These results indicate that endothelial ERα prevents the detrimental effects of MR in obesity by increasing NO to rescue vasodilation in females. MR and ERα may compete for striatin binding within endothelial cells to regulate NO. These data identify a novel mechanism that promotes MR antagonism to prevent obesity-induced microvascular dysfunction in females.

scholarly journals Uptake of chemically modified low density lipoproteins in vivo is mediated by specific endothelial cells.

1985 ◽  
Vol 100 (1) ◽  
pp. 103-117 ◽  
Author(s):  
R E Pitas ◽  
J Boyles ◽  
R W Mahley ◽  
D M Bissell
Keyword(s):  
Bone Marrow ◽  
Endothelial Cells ◽  
Kupffer Cells ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
Coated Pits ◽  
Sinusoidal Endothelial Cells ◽  
Modified Lipoproteins

Acetoacetylated (AcAc) and acetylated (Ac) low density lipoproteins (LDL) are rapidly cleared from the plasma (t1/2 approximately equal to 1 min). Because macrophages, Kupffer cells, and to a lesser extent, endothelial cells metabolize these modified lipoproteins in vitro, it was of interest to determine whether endothelial cells or macrophages could be responsible for the in vivo uptake of these lipoproteins. As previously reported, the liver is the predominant site of the uptake of AcAc LDL; however, we have found that the spleen, bone marrow, adrenal, and ovary also participate in this rapid clearance. A histological examination of tissue sections, undertaken after the administration of AcAc LDL or Ac LDL (labeled with either 125I or a fluorescent probe) to rats, dogs, or guinea pigs, was used to identify the specific cells binding and internalizing these lipoproteins in vivo. With both techniques, the sinusoidal endothelial cells of the liver, spleen, bone marrow, and adrenal were labeled. Less labeling was noted in the ovarian endothelia. Uptake of AcAc LDL by endothelial cells of the liver, spleen, and bone marrow was confirmed by transmission electron microscopy. These data suggest uptake through coated pits. Uptake of AcAc LDL was not observed in the endothelia of arteries (including the coronaries and aorta), veins, or capillaries of the heart, testes, kidney, brain, adipose tissue, and duodenum. Kupffer cells accounted for a maximum of 14% of the 125I-labeled AcAc LDL taken up by the liver. Isolated sinusoidal endothelial cells from the rat liver displayed saturable, high affinity binding of AcAc LDL (Kd = 2.5 X 10(-9) M at 4 degrees C), and were shown to degrade AcAc LDL 10 times more effectively than aortic endothelial cells. These data indicate that specific sinusoidal endothelial cells, not the macrophages of the reticuloendothelial system, are primarily responsible for the removal of these modified lipoproteins from the circulation in vivo.

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