scholarly journals Curcumin Alleviates Palmitic Acid-Induced LOX-1 Upregulation by Suppressing Endoplasmic Reticulum Stress in HUVECs

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Ruixi Luo ◽  
Lifeng Zhao ◽  
Shuaishuai Li ◽  
Peng Chen ◽  
La Wang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Palmitic Acid ◽  
Er Stress ◽  
Umbilical Vein ◽  
Low Density Lipoprotein ◽  
Critical Role ◽  
Density Lipoprotein ◽  
Low Density

Excessive free fatty acid- (FFA-) induced endothelial lipotoxicity is involved in the pathogenesis of atherosclerosis. Endoplasmic reticulum (ER) stress is mechanistically related to endothelial lipotoxicity. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major oxidatively modified low-density lipoprotein (OxLDL) receptor in endothelial cells and is highly abundant in atherosclerotic lesions. Curcumin reduces the LOX-1 expression; however, the mechanism underlying this effect remains unknown. In the current study, we explored whether curcumin ameliorates palmitic acid- (PA-) induced endothelial lipotoxicity and LOX-1 upregulation by reducing ER stress in human umbilical vein endothelial cells (HUVECs). We built endothelial lipotoxicity in vitro and found that LOX-1 was upregulated after PA stimulation, during which ER stress played an important role. Next, we observed that curcumin substantially alleviated PA-induced lipotoxicity by restoring cell viability, increasing angiogenesis, and decreasing lipid deposition. Furthermore, LOX-1 upregulation in HUVECs was blocked by curcumin, possibly via ER stress suppression. Overall, our findings demonstrated that curcumin alleviates endothelial lipotoxicity and LOX-1 upregulation, and ER stress inhibition may play a critical role in this effect.

scholarly journals MicroRNA-494 Regulates Endoplasmic Reticulum Stress in Endothelial Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Namita Chatterjee ◽  
Eugenia Fraile-Bethencourt ◽  
Adrian Baris ◽  
Cristina Espinosa-Diez ◽  
Sudarshan Anand
Keyword(s):  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Stress Responses ◽  
De Novo ◽  
Umbilical Vein ◽  
Critical Role ◽  
Umbilical Vein Endothelial Cells ◽  
And Control

Defects in stress responses are important contributors in many chronic conditions including cancer, cardiovascular disease, diabetes, and obesity-driven pathologies like non-alcoholic steatohepatitis (NASH). Specifically, endoplasmic reticulum (ER) stress is linked with these pathologies and control of ER stress can ameliorate tissue damage. MicroRNAs have a critical role in regulating diverse stress responses including ER stress. Here, we show that miR-494 plays a functional role during ER stress. Pharmacological ER stress inducers (tunicamycin (TCN) and thapsigargin) and hyperglycemia robustly increase the expression of miR-494 in vitro. ATF6 impacts the primary miR-494 levels whereas all three ER stress pathways are necessary for the increase in mature miR-494. Surprisingly, miR-494 pretreatment dampens the induction and magnitude of ER stress in response to TCN in endothelial cells and increases cell viability. Conversely, inhibition of miR-494 increases ER stress de novo and amplifies the effects of ER stress inducers. Using Mass Spectrometry (TMT-MS) we identified 23 proteins that are downregulated by both TCN and miR-494 in cultured human umbilical vein endothelial cells. Among these, we found 6 transcripts which harbor a putative miR-494 binding site. We validated the anti-apoptotic gene BIRC5 (survivin) and GINS4 as targets of miR-494 during ER stress. In summary, our data indicates that ER stress driven miR-494 may act in a feedback inhibitory loop to dampen downstream ER stress signaling.

Mesenchymal stem cells alleviate palmitic acid-induced endothelial-to-mesenchymal transition by suppressing endoplasmic reticulum stress

2020 ◽  
Vol 319 (6) ◽  
pp. E961-E980
Author(s):  
Ruixi Luo ◽  
Linzhao Li ◽  
Xiaohong Liu ◽  
Yujia Yuan ◽  
Wuzheng Zhu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Mesenchymal Stem Cells ◽  
Endothelial Dysfunction ◽  
Palmitic Acid ◽  
Er Stress ◽  
Critical Role ◽  
Mesenchymal Transition ◽  
Endothelial To Mesenchymal Transition

High levels of plasma free fatty acids (FFAs) lead to endothelial dysfunction (ED), which is involved in the pathogenesis of metabolic syndrome, diabetes, and atherosclerosis. Endoplasmic reticulum (ER) stress and endothelial-to-mesenchymal transition (EndMT) are demonstrated to be mechanistically related to endothelial dysfunction. Mesenchymal stem cells (MSCs) have exhibited an extraordinary cytoprotective effect on cellular lipotoxicity and vasculopathy. However, the underlying mechanisms have not been clearly defined. In the present study, we investigated whether MSCs could ameliorate palmitic acid (PA)-induced endothelial lipotoxicity by reducing ER stress and EndMT. We observed that MSC cocultures substantially alleviated PA-induced lipotoxicity in human umbilical vein endothelial cells (HUVECs). MSCs were able to restore the cell viability, increase tubule formation and migration ability, and decrease inflammation response and lipid deposition. Furthermore, PA caused endothelial-to-mesenchymal transition in HUVECs, which was abrogated by MSCs possibly through inhibiting ER stress. In addition, PA stimulated MSCs to secrete more stanniocalcin-1 (STC-1). Knocking down of STC-1 in MSCs attenuated their effects on PA-induced lipotoxicity in HUVECs. In vivo, MSC transplantation alleviated dyslipidemia and endothelial dysfunction in high-fat diet-fed Sprague–Dawley rats. MSC-treated rats showed reduced expressions of ER stress-related genes in aortas and suppressed expressions of EndMT-related proteins in rat aortic endothelial cells. Overall, our findings indicated that MSCs were able to attenuate endothelial lipotoxicity through inhibiting ER stress and EndMT, in which STC-1 secreted from MSCs may play a critical role.

scholarly journals Endocytosis of formaldehyde-treated serum albumin via scavenger pathway in liver endothelial cells

1984 ◽  
Vol 218 (1) ◽  
pp. 81-86 ◽  
Author(s):  
R Blomhoff ◽  
W Eskild ◽  
T Berg
Keyword(s):  
Endothelial Cells ◽  
Low Density Lipoprotein ◽  
Scavenger Receptor ◽  
Density Lipoprotein ◽  
Low Density ◽  
Surface Culture ◽  
Rat Liver Cells ◽  
Liver Endothelial Cells ◽  
Isolated Liver

Denatured or modified proteins (including albumin and low-density lipoprotein) are catabolized in vitro via scavenger receptors. We have studied the distribution of formaldehyde-denatured albumin in rat liver cells after intravenous injection of tracer doses of the protein. At 12 min after injection, most of the formaldehyde-denatured albumin (about 70% of the injected dose) was recovered in liver endothelial cells. Furthermore, isolated liver endothelial cells in suspension and in surface culture took up formaldehyde-denatured albumin by receptor-mediated endocytosis. Our data indicate that the scavenger receptor in liver is mainly located on the endothelial cells. Implications for the catabolism of low-density lipoproteins are discussed.

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