scholarly journals Metformin Inhibits Endoplasmic Reticulum Stress & Attenuates Autophagy in Glucose Starved Microvascular Endothelial Cells

2015 ◽  
Vol 29 (S1) ◽  
Author(s):  
Samson Samuel ◽  
Suparna Ghosh ◽  
Hong Ding ◽  
Chris Triggle
Keyword(s):  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Microvascular Endothelial Cells ◽  
Microvascular Endothelial

scholarly journals Characterization of Calcium Signals Provoked by Lysophosphatidylinositol in Human Microvascular Endothelial Cells

2016 ◽  
pp. 53-62 ◽  
Author(s):  
Y. M. AL SULEIMANI ◽  
C. R. HILEY
Keyword(s):  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Kinase Inhibitor ◽  
Microvascular Endothelial Cells ◽  
Ip3 Receptors ◽  
Rapid Phase ◽  
Lipid Molecule ◽  
Lipid Signalling ◽  
Rhoa Kinase ◽  
Microvascular Endothelial

The lipid molecule, lysophosphatidylinositol (LPI), is hypothesised to form part of a novel lipid signalling system that involves the G protein-coupled receptor GPR55 and distinct intracellular signalling cascades in endothelial cells. This work aimed to study the possible mechanisms involved in LPI-evoked cytosolic Ca2+ mobilization in human brain microvascular endothelial cells. Changes in intracellular Ca2+ concentrations were measured using cell population Ca2+ assay. LPI evoked biphasic elevation of intracellular calcium concentration, a rapid phase and a sustained phase. The rapid phase was attenuated by the inhibitor of PLC (U 73122), inhibitor of IP3 receptors, 2-APB and the depletor of endoplasmic reticulum Ca2+ store, thapsigargin. The sustained phase, on the other hand, was enhanced by U 73122 and abolished by the RhoA kinase inhibitor, Y-27632. In conclusion, the Ca2+ signal evoked by LPI is characterised by a rapid phase of Ca2+ release from the endoplasmic reticulum, and requires activation of the PLC-IP3 signalling pathway. The sustained phase mainly depends on RhoA kinase activation. LPI acts as novel lipid signalling molecule in endothelial cells, and elevation of cytosolic Ca2+ triggered by it may present an important intracellular message required in gene expression and controlling of vascular tone.

scholarly journals Ca2+ uptake by the endoplasmic reticulum Ca2+-ATPase in rat microvascular endothelial cells

2002 ◽  
Vol 364 (1) ◽  
pp. 235-244 ◽  
Author(s):  
Francesco MOCCIA ◽  
Roberto BERRA-ROMANI ◽  
Silvana BARUFFI ◽  
Santina SPAGGIARI ◽  
Silvia SIGNORELLI ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Time Course ◽  
Decay Phase ◽  
Pancreatic Acinar Cells ◽  
Microvascular Endothelial Cells ◽  
Excitable Cells ◽  
Extracellular Medium ◽  
Serca Pump ◽  
Microvascular Endothelial

In non-excitable cells, many agonists increase the intracellular Ca2+ concentration ([Ca2+]i) by inducing an inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ release from the intracellular stores. Ca2+ influx from the extracellular medium may then sustain the Ca2+ signal. [Ca2+]i recovers its resting level as a consequence of Ca2+-removing mechanisms, i.e. plasma-membrane Ca2+-ATPase (PMCA) pump, Na+/Ca2+ exchanger (NCX) and sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) pump. In a study performed in pancreatic acinar cells, evidence has been provided suggesting that, during the decay phase of the agonist-evoked Ca2+ transients, the Ca2+ concentration within the intracellular stores remains essentially constant [Mogami, Tepikin and Petersen (1998) EMBO J. 17, 435–442]. It was therefore hypothesized that, in such a situation, intracellular Ca2+ is not only picked up by the SERCA pump, but is also newly released through IP3-sensitive Ca2+ channels, with the balance between these two processes being approximately null. The main aim of the present work was to test this hypothesis by a different experimental approach. Using cardiac microvascular endothelial cells, we found that inhibition of the SERCA pump has no effect on the time course of agonist-evoked Ca2+ transients. This result was not due to a low capacity of the SERCA pump since, after agonist removal, this pump proved to be very powerful in clearing the excess of intracellular Ca2+. We showed further that: (i) in order to avoid a rapid removal of Ca2+ by the SERCA pump, continuous IP3 production appears to be required throughout all of the decay phase of the Ca2+ transient; and (ii) Ca2+ picked up by the SERCA pump can be fully and immediately released by agonist application. All these results support the model of Mogami, Tepikin and Petersen [(1998) EMBO J. 17, 435–442]. Since the SERCA pump did not appear to be involved in shaping the decay phase of the agonist-evoked Ca2+ transient, we inhibited the PMCA pump with carboxyeosin, and NCX with benzamil and by removing extracellular Na+. The results indicate that, during the decay phase of the agonist-evoked Ca2+ transient, the intracellular Ca2+ is removed by both the PMCA pump and NCX. Finally, we provide evidence indicating that mitochondria have no role in clearing intracellular Ca2+ during agonist-evoked Ca2+ transients.

scholarly journals Multifunctional Liposomes Modulate Purinergic Receptor-Induced Calcium Wave in Cerebral Microvascular Endothelial Cells and Astrocytes: New Insights for Alzheimer’s disease

2021 ◽  
Author(s):  
Greta Forcaia ◽  
Beatrice Formicola ◽  
Giulia Terribile ◽  
Sharon Negri ◽  
Dmitry Lim ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Purinergic Receptor ◽  
P2y Receptors ◽  
Microvascular Endothelial Cells ◽  
Cultured Astrocytes ◽  
Intracellular Ca ◽  
Microvascular Endothelial

AbstractIn light of previous results, we assessed whether liposomes functionalized with ApoE-derived peptide (mApoE) and phosphatidic acid (PA) (mApoE-PA-LIP) impacted on intracellular calcium (Ca2+) dynamics in cultured human cerebral microvascular endothelial cells (hCMEC/D3), as an in vitro human blood-brain barrier (BBB) model, and in cultured astrocytes. mApoE-PA-LIP pre-treatment actively increased both the duration and the area under the curve (A.U.C) of the ATP-evoked Ca2+ waves in cultured hCMEC/D3 cells as well as in cultured astrocytes. mApoE-PA-LIP increased the ATP-evoked intracellular Ca2+ waves even under 0 [Ca2+]e conditions, thus indicating that the increased intracellular Ca2+ response to ATP is mainly due to endogenous Ca2+ release. Indeed, when Sarco-Endoplasmic Reticulum Calcium ATPase (SERCA) activity was blocked by cyclopiazonic acid (CPA), the extracellular application of ATP failed to trigger any intracellular Ca2+ waves, indicating that metabotropic purinergic receptors (P2Y) are mainly involved in the mApoE-PA-LIP-induced increase of the Ca2+ wave triggered by ATP. In conclusion, mApoE-PA-LIP modulate intracellular Ca2+ dynamics evoked by ATP when SERCA is active through inositol-1,4,5-trisphosphate-dependent (InsP3) endoplasmic reticulum Ca2+ release. Considering that P2Y receptors represent important pharmacological targets to treat cognitive dysfunctions, and that P2Y receptors have neuroprotective effects in neuroinflammatory processes, the enhancement of purinergic signaling provided by mApoE-PA-LIP could counteract Aβ-induced vasoconstriction and reduction in cerebral blood flow (CBF). Our obtained results could give an additional support to promote mApoE-PA-LIP as effective therapeutic tool for Alzheimer’s disease (AD).

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