1,720,982 research outputs found
DIFFERENT PATTERNS OF Ca2+ SIGNALING DRIVE ACETYLCHOLINE AND GLUTAMATE INDUCED-NO RELEASE IN MOUSE AND HUMAN BRAIN MICROVASCULAR ENDOTHELIAL CELLS
Full text linkAcetylcholine (Ach) and glutamate (Glu) are two of the major excitatory neurotransmitters in the brain which increase cerebral blood flow by releasing nitric oxide (NO) from postsynaptic neurons and astrocytes and causing vasorelaxationin adjacent microvessels. An increase in intracellular Ca2+ concentration recruits a multitude of endothelial Ca2+-dependent pathways, such as Ca2+/Calmodulin endothelial NO synthase (eNOS). Surprisingly, the Ca2+-dependent mechanisms whereby Ach induces NO synthesis in brain endothelial cells (ECs) is still unclear. On the other hand, Glu stimulates NMDA receptors to activate eNOS, but it is able to cause a metabotropic increase in intracellular Ca2+ concentration in brain microvascular ECs. The present investigation sought to fill these gaps by analysing murine (bEND5) and human (hCMEC/D3) brain microvascular ECs.
Herein, we first demonstrated that Ach induces NO release by triggering two different modes of Ca2+ signals in bEND5 and hCMEC/D3 cells. Of note, endoplasmic reticulum Ca2+ release via inositol-1,4,5-trisphosphate receptors and store-operated Ca2+ entry shapes the Ca2+ response to Ach in both cell types but their different Ca2+ toolkits result in two quite different waveforms, i.e. Ca2+ oscillations vs. biphasic Ca2+ elevation. Whatever its waveform, however, Ach-induced intracellular Ca2+ signals lead to robust NO release in both murine and human brain microvascular ECs. Likewise, we demonstrated for the first time that Glu activated metabotropic intracellular Ca2+ oscillation in bEND5 cells and a biphasic increase in intracellular Ca2+ concentration in hCMEC/D3 cells. We further showed that glutamate-dependent Ca2+ signals drive NO release in both types of cells. This NO signal is delayed as compared to the Ach-induced one and is likely to play a crucial role in the slower vasodilation that often follows brief neuronal activity or that sustains functional hyperemia during persistent synaptic transmission.
This information has a potential clinical relevance as the decrease in neuronal activity-induced cortical CBF is involved in a growing number of neurodegenerative disorders, such as Alzheimer’s Disease. Understanding the underlying mechanisms could, therefore, be used in the future as target to rescue local blood perfusion in patients affected by neurodegenerative disorders
Intracellular Ca2+ signals to reconstruct a broken heart: Still a theoretical approach?
No full textThe infusion of autologous stem cells has recently been put forward as an alternative strategy to regenerate infarcted myocardium and restore the contractile functions of diseased hearts. A growing number of cell types have been probed to induce cardiac repair in several animal models of ischemic myocardium, including human cardiac progenitor cells (hCPCs), human embryonic stem cells (hESCs), human mesenchymal stem cells (hMSCs) and human endothelial progenitor cells (hEPCs). The enthusiasm raised by pre-clinical studies has been dampened by clinical practice, according to which the extent of cardiac repair by cell based therapy is inadequate as respect to animal models. There is no doubt that regenerative medicine of acute myocardial infarction (AMI) will greatly benefit from the full comprehension of the signal transduction pathways which guide stem cell towards the injury site and their subsequent acquisition of a therapeutically relevant phenotype. The present review will focus on the role that oscillations in intracellular Ca2+ concentration might play to promote the stem cells-dependent regrowth of ischemic myocardium. We will describe how intracellular Ca2+ spikes may be manipulated to redirect stem cell fate to the most suitable lineage to restore cardiac vascularisation and contractility
Arachidonic acid stimulates endothelial progenitor cell proliferation through an increase in Ca2+ concentration and nitric oxide production
Full text linkIntracellular Ca2+ oscillations mediate acetylcholine-induced nitric oxide release in mouse brain endothelial cells
No full textEndothelial progenitor cells support tumour growth and metastatisation: implications for the resistance to anti-angiogenic therapy
No full textAcidic Ca2+ stores interact with the endoplasmic reticulum to shape intracellular Ca2+ signals in human endothelial progenitor cells
Full text linkTargeting Stim and Orai proteins as an alternative approach in anticancer therapy
No full textAn increase in intracellular Ca2+ concentration plays a key role in the establishment of many cancer hallmarks, including aberrant proliferation, migration, invasion, resistance to apoptosis and angiogenesis. The dysregulation of Ca2+ entry is one of the most subtle mechanisms by which cancer cells overwhelm their normal counterparts and gain the adaptive advantages that result in tumour growth, vascularisation and dissemination throughout the organism. Both constitutive and agonist-induced Ca2+ influx may be mediated by store-dependent as well as store-independent Ca2+ entry routes. A growing body of evidences have shown that different isoforms of Stromal Interaction Molecules (Stim1) and Orai proteins, i.e. Stim1, Stim2, Orai1 and Orai3, underlie both pathways in cancer cells. The alteration in either the expression or the activity of Stim and Orai proteins has been linked to the onset and maintenance of tumour phenotype in many solid malignancies, including prostate, breast, kidney, esophageal, skin, brain, colorectal, lung and liver cancers. Herein, we survey the existing data in support of Stim and Orai involvement in tumourigenesis and provide the rationale to target them in cancer patients. Besides, we summarize the most recent advances in the identification of novel pharmacological tools that could be successfully used in clinical therapy
Liposomes as a Putative Tool to Investigate NAADP Signaling in Vasculogenesis
Full text linkNicotinic acid adenine dinucleotide phosphate (NAADP) is the newest discovered intracellular second messengers, which is able to release Ca(2+) stored within endolysosomal (EL) vesicles. NAADP-induced Ca(2+) signals mediate a growing number of cellular functions, ranging from proliferation to muscle contraction and differentiation. Recently, NAADP has recently been shown to regulate angiogenesis by promoting endothelial cell growth. It is, however, still unknown whether NAADP stimulates proliferation also in endothelial progenitor cells, which are mobilized in circulation after an ischemic insult to induce tissue revascularization. Herein, we described a novel approach to prepare NAADP-containing liposomes, which are highly cell membrane permeable and are therefore amenable for stimulating cell activity. Accordingly, NAADP-containing liposomes evoked an increase in intracellular Ca(2+) concentration, which was inhibited by NED-19, a selective inhibitor of NAADP-induced Ca(2+) release. Furthermore, NAADP-containing liposomes promoted EPC proliferation, a process which was inhibited by NED-19 and BAPTA, a membrane permeable intracellular Ca(2+) buffer. Therefore, NAADP-containing liposomes stand out as a promising tool to promote revascularization of hypoxic/ischemic tissues by favoring EPC proliferation. J. Cell. Biochem. 9999: 1-8, 2017. © 2017 Wiley Periodicals, Inc
Acetylcholine induces intracellular Ca2+ oscillations and nitric oxide release in mouse brain endothelial cells
Full text linkBasal forebrain neurons increase cortical blood flow by releasing acetylcholine (Ach), which stimulates endothelial cells (ECs) to produce the vasodilating gasotransmitter, nitric oxide (NO). Surprisingly, the mechanism whereby Ach induces NO synthesis in brain microvascular ECs is unknown. An increase in intracellular Ca2 + concentration recruits a multitude of endothelial Ca2 +-dependent pathways, such as Ca2 +/calmodulin endothelial NO synthase (eNOS). The present investigation sought to investigate the role of intracellular Ca2 + signaling in Ach-induced NO production in bEnd5 cells, an established model of mouse brain microvascular ECs, by conventional imaging of cells loaded with the Ca2+-sensitive dye, Fura-2/AM, and the NO-sensitive fluorophore, DAF-DM diacetate. Overall, our data shed novel light on the molecular mechanisms whereby neuronally-released Ach controls neurovascular coupling in blood microvessels
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