scholarly journals Life-Long Hyperbilirubinemia Exposure and Bilirubin Priming Prevent In Vitro Metabolic Damage

2021 ◽  
Vol 12 ◽  
Author(s):  
Annalisa Bianco ◽  
Serena Pinci ◽  
Claudio Tiribelli ◽  
Cristina Bellarosa

Background: Unconjugated bilirubin (UCB) is more than the final product of heme catabolism. Mildly elevated systemic bilirubin concentrations, such as in Gilbert syndrome (GS), protect against various oxidative stress-mediated and metabolic diseases, including cardiovascular disease, type 2 diabetes mellitus, metabolic syndrome, cancer, and age-related disease. The Gunn rat is an animal model of hereditary hyperbilirubinemia widely used in assessing the effect of high serum bilirubin concentration in various organs. The present work aims to understand if life-long hyperbilirubinemia and bilirubin-priming might contribute to protection against atherosclerosis and diabetic nephropathy (DN) at the cellular level.Methods: Primary aortic endothelial cells and podocytes obtained from hyperbilirubinemic homozygous jj and normobilirubinemic heterozygous Nj Gunn rats were exposed to Palmitic Acid (PA) and Angiotensin II (Ang II), respectively, and the effects on cell viability and the activation of damage-related metabolic pathways evaluated. Results were validated on immortalized H5V and HK2 cells exposed to damage after UCB pretreatment.Results: In both primary cell models, cells obtained from jj Gunn rats showed as significantly higher than Nj Gunn rats at any dose of the toxic agent. Reduction in CHOP expression and IL-6 release was observed in jj primary aortic endothelial cells exposed to PA compared to Nj cells. The same occurred on H5V pretreated with Unconjugated bilirubin. Upon Ang II treatment, primary podocytes from jj Gunn rats showed lower DNA fragmentation, cleaved caspase-3, and cleaved PARP induction than primary podocytes from Nj Gunn rats. In HK2 cells, the induction by Ang II of HIF-1α and LOXl2 was significantly reduced by UCB pretreatment.Conclusion: Our data suggest that in models of atherosclerosis and DN life–long hyperbilirubinemia exposure or bilirubin-priming significantly contribute to decrease the injury by enhancing thecellular defensive response,

2000 ◽  
Vol 164 (2) ◽  
pp. 207-214 ◽  
Author(s):  
F Xiao ◽  
GP Vinson ◽  

One controversy in the field of vascular angiotensin generation has surrounded the nature and particularly the source of vascular renin. This study investigated the expression of renin protein and its mRNA in aortic endothelial cells using immunocytochemistry, Western blotting, in situ hybridization and reverse transcription PCR (RT-PCR). Using a monoclonal antibody against human renin, immunocytochemical analysis revealed positive immunoreactivity in the cytoplasm of cultured bovine aortic endothelial cells. Immunoblotting of solubilized proteins separated by SDS-PAGE from cultured aortic endothelial cells identified two immunoreactive species with molecular masses of approximately 37-40 kDa. In situ hybridization showed that renin mRNA was localized in the cytoplasm of these cells. Using RT-PCR of RNA extracted from bovine aortic endothelial cells with primers specific for human renin, a clear single band was detected, which had the predicted size of 142 bp for (pro)renin. Angiotensin II (Ang II) was assayed in conditioned medium (CM) from cultured bovine aortic endothelial cells, and in addition, the effects of Ang II and CM on the proliferation of aorta smooth muscle cells (ASMC) were also studied. The results showed that CM contained Ang II equivalent to 15.05+/-4.67 pg/10(6) cells. Assay of smooth muscle cell proliferation by cell number, and by tritiated thymidine uptake, showed that proliferative responses in the presence of Ang II at a concentration of 10(-6)M were evident within 1 day of subculture, and cell numbers were nearly twice those of controls after 2 days. Thymidine incorporation into ASMC was also increased by Ang II in a dose-dependent manner and by endothelial cell CM. In both cases, stimulated proliferation was inhibited by the Ang II type 1 (AT1) receptor selective antagonist, losartan. These findings suggest that these vascular endothelial cells are a source of locally synthesized renin that may thus be involved in vascular Ang II generation. They also suggest that Ang II produced by the endothelial cells may be secreted and stimulate ASMC proliferation via the AT1 receptor.


1999 ◽  
Vol 82 (11) ◽  
pp. 1516-1521 ◽  
Author(s):  
Hajime Tsuji ◽  
Haruchika Masuda ◽  
Teruhisa Kasahara ◽  
Masami Yoshizumi ◽  
Tatsuya Sugano ◽  
...  

SummaryNot only angiotensin II (Ang II) but also other angiotensin metabolites such as angiotensin I (Ang I), angiotensin III (Ang III), angiotensin IV, or angiotensin 1-7 have recently been reported to have various activities. Few data, however, are available on the regulation of thrombus formation. In this study, we investigated the effects of angiotensin metabolites on the mRNA expression of tissue factor (TF), tissue factor pathway inhibitor (TFPI), plasminogen activator inhibitor-1 (PAI-1), and tissue type plasminogen activator (TPA) in cultured rat aortic endothelial cells. None of the used angiotensin metabolites altered TFPI or TPA mRNA expression levels. Ang I, Ang II, and Ang III made TF and PAI-1 mRNA inductions which were inhibited by an selective antagonist of angiotensin II type 1 receptors. These metabolites made TF predominant to TFPI or PAI-1 to TPA, and could render endothelial cells thrombogenic.


1989 ◽  
Vol 256 (5) ◽  
pp. C987-C993 ◽  
Author(s):  
J. M. Patel ◽  
F. R. Yarid ◽  
E. R. Block ◽  
M. K. Raizada

Angiotensin II (ANG II) is formed from angiotensin I by the action of angiotensin-converting enzyme located on the luminal surface of vascular endothelial cells. We determined whether binding sites specific for ANG II exist on pulmonary artery and aortic endothelial cells. The binding of 125I-ANG II to pulmonary artery and aortic endothelial cells was time dependent, saturable, and reversible. Scatchard analysis indicated a single class of high-affinity binding sites with equilibrium dissociation constants (Kd) of 0.85 and 0.81 nM and total binding capacities of 70 and 73 fmol/mg protein in pulmonary artery and aortic endothelial cells, respectively. Angiotensin analogues [Sar1,Ile8]ANG II and [Sar1,Ala8]ANG II, as well as angiotensin I and angiotensin III, competitively displaced 125I-ANG II in both pulmonary artery and aortic endothelial cells. The degree of inhibition of 125I-ANG II binding by these angiotensin analogues and antagonists was comparable except that [Sar1,Ala8]ANG II was 65% less potent than the other antagonists in both cell types. The binding of 125I-ANG II in pulmonary artery and aortic endothelial cells was not affected by vasopressin, substance P, or insulin, suggesting the presence of specific angiotensin receptors on these cells. These receptors appear to recognize the general configuration of angiotensin peptide rather than being specific to ANG II with no major differences between endothelial cells from pulmonary arterial or aortic vessels.


1983 ◽  
Vol 49 (02) ◽  
pp. 132-137 ◽  
Author(s):  
A Eldor ◽  
G Polliack ◽  
I Vlodavsky ◽  
M Levy

SummaryDipyrone and its metabolites 4-methylaminoantipyrine, 4-aminoantipyrine, 4-acetylaminoantipyrine and 4-formylaminoan- tipyrine inhibited the formation of thromboxane A2 (TXA2) during in vitro platelet aggregation induced by ADP, epinephrine, collagen, ionophore A23187 and arachidonic acid. Inhibition occurred after a short incubation (30–40 sec) and depended on the concentration of the drug or its metabolites and the aggregating agents. The minimal inhibitory concentration of dipyrone needed to completely block aggregation varied between individual donors, and related directly to the inherent capacity of their platelets to synthesize TXA2.Incubation of dipyrone with cultured bovine aortic endothelial cells resulted in a time and dose dependent inhibition of the release of prostacyclin (PGI2) into the culture medium. However, inhibition was abolished when the drug was removed from the culture, or when the cells were stimulated to produce PGI2 with either arachidonic acid or ionophore A23187.These results indicate that dipyrone exerts its inhibitory effect on prostaglandins synthesis by platelets or endothelial cells through a competitive inhibition of the cyclooxygenase system.


2021 ◽  
Vol 9 (1) ◽  
pp. e002085
Author(s):  
Yuan Wei ◽  
Suwen Bai ◽  
YanHeng Yao ◽  
Wenxuan Hou ◽  
Junwei Zhu ◽  
...  

IntroductionDiabetes-associated endothelial barrier function impairment might be linked to disturbances in Ca2+ homeostasis. To study the role and molecular mechanism of Orais–vascular endothelial (VE)-cadherin signaling complex and its downstream signaling pathway in diabetic endothelial injury using mouse aortic endothelial cells (MAECs).Research design and methodsThe activity of store-operated Ca2+ entry (SOCE) was detected by calcium imaging after 7 days of high-glucose (HG) or normal-glucose (NG) exposure, the expression levels of Orais after HG treatment was detected by western blot analysis. The effect of HG exposure on the expression of phosphorylated (p)-VE-cadherin and VE-cadherin on cell membrane was observed by immunofluorescence assay. HG-induced transendothelial electrical resistance was examined in vitro after MAECs were cultured in HG medium. FD-20 permeability was tested in monolayer aortic endothelial cells through transwell permeability assay. The interactions between Orais and VE-cadherin were detected by co-immunoprecipitation and immunofluorescence technologies. Immunohistochemical experiment was used to detect the expression changes of Orais, VE-cadherin and p-VE-cadherin in aortic endothelium of mice with diabetes.Results(1) The expression levels of Orais and activity of SOCE were significantly increased in MAECs cultured in HG for 7 days. (2) In MAECs cultured in HG for 7 days, the ratio of p-VE-cadherin to VE-cadherin expressed on the cell membrane and the FD-20 permeability in monolayer endothelial cells increased, indicating that intercellular permeability increased. (3) Orais and VE-cadherin can interact and enhance the interaction ratio through HG stimulation. (4) In MAECs cultured with HG, the SOCE activator ATP enhanced the expression level of p-VE-cadherin, and the SOCE inhibitor BTP2 decreased the expression level of p-VE-cadherin. (5) Significantly increased expression of p-VE-cadherin and Orais in the aortic endothelium of mice with diabetes.ConclusionHG exposure stimulated increased expression of Orais in endothelial cells, and increased VE-cadherin phosphorylation through Orais–VE-cadherin complex and a series of downstream signaling pathways, resulting in disruption of endothelial cell junctions and initiation of atherosclerosis.


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