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Cilek N, Ugurel E, Goksel E, Yalcin O. Signaling mechanisms in red blood cells: A view through the protein phosphorylation and deformability. J Cell Physiol 2024; 239:e30958. [PMID: 36748950 DOI: 10.1002/jcp.30958] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/07/2023] [Accepted: 01/19/2023] [Indexed: 02/08/2023]
Abstract
Intracellular signaling mechanisms in red blood cells (RBCs) involve various protein kinases and phosphatases and enable rapid adaptive responses to hypoxia, metabolic requirements, oxidative stress, or shear stress by regulating the physiological properties of the cell. Protein phosphorylation is a ubiquitous mechanism for intracellular signal transduction, volume regulation, and cytoskeletal organization in RBCs. Spectrin-based cytoskeleton connects integral membrane proteins, band 3 and glycophorin C to junctional proteins, ankyrin and Protein 4.1. Phosphorylation leads to a conformational change in the protein structure, weakening the interactions between proteins in the cytoskeletal network that confers a more flexible nature for the RBC membrane. The structural organization of the membrane and the cytoskeleton determines RBC deformability that allows cells to change their ability to deform under shear stress to pass through narrow capillaries. The shear stress sensing mechanisms and oxygenation-deoxygenation transitions regulate cell volume and mechanical properties of the membrane through the activation of ion transporters and specific phosphorylation events mediated by signal transduction. In this review, we summarize the roles of Protein kinase C, cAMP-Protein kinase A, cGMP-nitric oxide, RhoGTPase, and MAP/ERK pathways in the modulation of RBC deformability in both healthy and disease states. We emphasize that targeting signaling elements may be a therapeutic strategy for the treatment of hemoglobinopathies or channelopathies. We expect the present review will provide additional insights into RBC responses to shear stress and hypoxia via signaling mechanisms and shed light on the current and novel treatment options for pathophysiological conditions.
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Affiliation(s)
- Neslihan Cilek
- Research Center for Translational Medicine (KUTTAM), Koc University, Istanbul, Turkey
- School of Medicine, Koc University, Istanbul, Turkey
- Graduate School of Health Sciences, Koc University, Istanbul, Turkey
| | - Elif Ugurel
- Research Center for Translational Medicine (KUTTAM), Koc University, Istanbul, Turkey
- School of Medicine, Koc University, Istanbul, Turkey
| | - Evrim Goksel
- Research Center for Translational Medicine (KUTTAM), Koc University, Istanbul, Turkey
- School of Medicine, Koc University, Istanbul, Turkey
- Graduate School of Health Sciences, Koc University, Istanbul, Turkey
| | - Ozlem Yalcin
- Research Center for Translational Medicine (KUTTAM), Koc University, Istanbul, Turkey
- School of Medicine, Koc University, Istanbul, Turkey
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2
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Ugurel E, Connes P, Yavas G, Eglenen B, Turkay M, Aksu AC, Renoux C, Joly P, Gauthier A, Hot A, Bertrand Y, Cannas G, Yalcin O. Differential effects of adenylyl cyclase-protein kinase A cascade on shear-induced changes of sickle cell deformability. Clin Hemorheol Microcirc 2020; 73:531-543. [DOI: 10.3233/ch-190563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Elif Ugurel
- Department of Physiology, Koç University School of Medicine, Sariyer, Istanbul, Turkey
| | - Philippe Connes
- Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Team « Vascular Biology and Red Blood Cell », Université Claude Bernard Lyon 1, Lyon, France
- Laboratoire d’Excellence du Globule Rouge (Labex GR-Ex), PRES Sorbonne, Paris, France
- Institut Universitaire de France (IUF), Paris, France
| | - Gokce Yavas
- Department of Physiology, Koç University School of Medicine, Sariyer, Istanbul, Turkey
| | - Buse Eglenen
- Department of Physiology, Koç University School of Medicine, Sariyer, Istanbul, Turkey
| | - Mine Turkay
- Department of Physiology, Koç University School of Medicine, Sariyer, Istanbul, Turkey
| | - Ali Cenk Aksu
- Department of Physiology, Koç University School of Medicine, Sariyer, Istanbul, Turkey
| | - Celine Renoux
- Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Team « Vascular Biology and Red Blood Cell », Université Claude Bernard Lyon 1, Lyon, France
- Laboratoire d’Excellence du Globule Rouge (Labex GR-Ex), PRES Sorbonne, Paris, France
- UF de biochimie des pathologies érythrocytaires, Centre de Biologie Est, Hospices Civils de Lyon, Lyon, France
| | - Philippe Joly
- Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Team « Vascular Biology and Red Blood Cell », Université Claude Bernard Lyon 1, Lyon, France
- Laboratoire d’Excellence du Globule Rouge (Labex GR-Ex), PRES Sorbonne, Paris, France
- UF de biochimie des pathologies érythrocytaires, Centre de Biologie Est, Hospices Civils de Lyon, Lyon, France
| | - Alexandra Gauthier
- Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Team « Vascular Biology and Red Blood Cell », Université Claude Bernard Lyon 1, Lyon, France
- Laboratoire d’Excellence du Globule Rouge (Labex GR-Ex), PRES Sorbonne, Paris, France
- Institut d’hématologie et d’oncologie pédiatrique (IHOP), Hospices Civils de Lyon, Lyon, France
| | - Arnaud Hot
- Clinique de Médecine Ambulatoire/Hématologie Hôpital Edouard Herriot, Lyon, Lyon, France
| | - Yves Bertrand
- Institut d’hématologie et d’oncologie pédiatrique (IHOP), Hospices Civils de Lyon, Lyon, France
| | - Giovanna Cannas
- Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Team « Vascular Biology and Red Blood Cell », Université Claude Bernard Lyon 1, Lyon, France
- Laboratoire d’Excellence du Globule Rouge (Labex GR-Ex), PRES Sorbonne, Paris, France
- Clinique de Médecine Ambulatoire/Hématologie Hôpital Edouard Herriot, Lyon, Lyon, France
| | - Ozlem Yalcin
- Department of Physiology, Koç University School of Medicine, Sariyer, Istanbul, Turkey
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Semenov AN, Shirshin EA, Muravyov AV, Priezzhev AV. The Effects of Different Signaling Pathways in Adenylyl Cyclase Stimulation on Red Blood Cells Deformability. Front Physiol 2019; 10:923. [PMID: 31474870 PMCID: PMC6702543 DOI: 10.3389/fphys.2019.00923] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022] Open
Abstract
Signaling pathways of red blood cells’ (RBCs) micromechanics regulation, which are responsible for maintaining microcirculation, constitute an important property of RBC physiology. Selective control over these processes may serve as an indispensable tool for correction of hemorheological disorders, which accompany a number of systemic diseases (diabetes mellitus I&II, arterial hypertension, malaria, etc.). Activation of certain pathways involving adenylyl cyclase may provide fast adaptive regulation of RBC deformability (RBC-D). However the specific molecular conditions of intracellular signal transduction in mediating RBC microrheological properties at adenylyl cyclase stimulation remain unclear. In this paper, we present the results of the in vitro study of the effects of different signaling pathways in adenylyl cyclase stimulation on RBC-D. We studied (1) the direct stimulation of adenylyl cyclase with forskolin; (2) non-selective adrenoreceptor stimulation with epinephrine; (3) β2-adrenoreceptor agonist metaproterenol; (4) membrane-permeable analog of cAMP (dibutyryl-cAMP). Using laser ektacytometry, we observed a concentration-dependent increase in RBC-D for all studied effectors. The EC50 values for each substance were estimated to be in the range of 1–100 μM depending on the shear stress applied to the RBC suspension. The results can serve as an evidence of adenylyl cyclase signaling cascade involvement in the regulation of RBC micromechanical properties presenting a complex molecular pathway for fast increase of microcirculation efficiency in case of corresponding physiologic metabolic demands of the organism, e.g., during stress or physical activity. Further studies of this molecular system will reveal new knowledge which may improve the quality of medical treatment of hemorheological disorders.
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Affiliation(s)
| | - Evgeny A Shirshin
- Department of Physics, Moscow State University, Moscow, Russia.,International Laser Center, Moscow State University, Moscow, Russia
| | - Alexei V Muravyov
- Department of Medicine and Biology, Yaroslavl State Pedagogical University, Yaroslavl, Russia
| | - Alexander V Priezzhev
- Department of Physics, Moscow State University, Moscow, Russia.,International Laser Center, Moscow State University, Moscow, Russia
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Barvitenko NN, Aslam M, Filosa J, Matteucci E, Nikinmaa M, Pantaleo A, Saldanha C, Baskurt OK. Tissue oxygen demand in regulation of the behavior of the cells in the vasculature. Microcirculation 2014; 20:484-501. [PMID: 23441854 DOI: 10.1111/micc.12052] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/19/2013] [Indexed: 12/20/2022]
Abstract
The control of arteriolar diameters in microvasculature has been in the focus of studies on mechanisms matching oxygen demand and supply at the tissue level. Functionally, important vascular elements include EC, VSMC, and RBC. Integration of these different cell types into functional units aimed at matching tissue oxygen supply with tissue oxygen demand is only achieved when all these cells can respond to the signals of tissue oxygen demand. Many vasoactive agents that serve as signals of tissue oxygen demand have their receptors on all these types of cells (VSMC, EC, and RBC) implying that there can be a coordinated regulation of their behavior by the tissue oxygen demand. Such functions of RBC as oxygen carrying by Hb, rheology, and release of vasoactive agents are considered. Several common extra- and intracellular signaling pathways that link tissue oxygen demand with control of VSMC contractility, EC permeability, and RBC functioning are discussed.
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Knebel SM, Elrick MM, Bowles EA, Zdanovec AK, Stephenson AH, Ellsworth ML, Sprague RS. Synergistic effects of prostacyclin analogs and phosphodiesterase inhibitors on cyclic adenosine 3',5' monophosphate accumulation and adenosine 3'5' triphosphate release from human erythrocytes. Exp Biol Med (Maywood) 2013; 238:1069-74. [PMID: 23986226 DOI: 10.1177/1535370213498981] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Prostacyclin (PGI2) and phosphodiesterase 5 (PDE5) inhibitors are potent vasodilators that are used alone and in combination for the treatment of pulmonary arterial hypertension (PAH). Although these vasodilators are known to stimulate relaxation of vascular smooth muscle directly, other cells in circulation, including erythrocytes, express prostacyclin receptor (IPR) and contain PDE5. The binding of PGI2 analogs to the erythrocyte IPR results in activation of a signaling pathway that increases cyclic adenosine 3',5' monophosphate (cAMP), a requirement for adenosine 3'5' triphosphate (ATP) release. Within this pathway, cAMP levels are regulated by phosphodiesterase 3 (PDE3), a PDE that is inhibited by cGMP, a cyclic nucleotide regulated by the activity of PDE5. Since inhibition of PDE3 enhances ATP release in response to PGI2 analogs, we investigated if the selective PDE5 inhibitors, zaprinast (ZAP) and tadalafil (TAD), would similarly increase cAMP and ATP release from human erythrocytes in response to the same stimulus. We determined that pretreatment of erythrocytes with one of two chemically dissimilar PDE5 inhibitors (ZAP or TAD, 10 µM) potentiated increases in cAMP and ATP release in response to incubation of human erythrocytes with the PGI2 analog, UT-15C (100 nM). These results suggest that a heretofore unrecognized synergism exists between IPR agonists and PDE5 inhibitors that could provide a new rationale for the co-administration of these agents as vasodilators in humans with PAH.
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Affiliation(s)
- Stephanie M Knebel
- Department of Pharmacological and Physiological Science, Saint Louis University, St. Louis, MO 63104, USA
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Sprague RS, Ellsworth ML. Erythrocyte-derived ATP and perfusion distribution: role of intracellular and intercellular communication. Microcirculation 2012; 19:430-9. [PMID: 22775760 PMCID: PMC3324633 DOI: 10.1111/j.1549-8719.2011.00158.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In complex organisms, both intracellular and intercellular communication are critical for the appropriate regulation of the distribution of perfusion to assure optimal O(2) delivery and organ function. The mobile erythrocyte is in a unique position in the circulation as it both senses and responds to a reduction in O(2) tension in its environment. When erythrocytes enter a region of the microcirculation in which O(2) tension is reduced, they release both O(2) and the vasodilator, ATP, via activation of a specific and dedicated signaling pathway that requires increases in cAMP, which are regulated by PDE3B. The ATP released initiates a conducted vasodilation that results in alterations in the distribution of perfusion to meet the tissue's metabolic needs. This delivery mechanism is modulated by both positive and negative feedback regulators. Importantly, defects in low O(2) -induced ATP release from erythrocytes have been observed in several human disease states in which impaired vascular function is present. Understanding of the role of erythrocytes in controlling perfusion distribution and the signaling pathways that are responsible for ATP release from these cells makes the erythrocyte a novel therapeutic target for the development of new approaches for the treatment of vascular dysfunction.
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Affiliation(s)
- Randy S Sprague
- Saint Louis University School of Medicine, St. Louis, Missouri, USA.
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7
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Ellsworth ML, Sprague RS. Regulation of blood flow distribution in skeletal muscle: role of erythrocyte-released ATP. J Physiol 2012; 590:4985-91. [PMID: 22586223 DOI: 10.1113/jphysiol.2012.233106] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The maintenance of adequate tissue O(2) levels in skeletal muscle is vital for normal physiology and requires a well regulated and appropriately distributed convective O(2) supply. Inherent in this fundamental physiological process is the requirement for a mechanism which both senses tissue O(2) need and locally adjusts flow to appropriately meet that need. Over the past several years we and others have suggested that, in skeletal muscle, O(2) carrying erythrocytes participate in the regulation of total blood flow and its distribution by releasing ATP. Importantly, the release of this vasoactive molecule must be both rapid and well controlled if it is to serve an important physiological role. Here we provide insights into three distinct regulated signalling pathways within the erythrocyte that are activated by exposure to reduced O(2) tension or in response to binding of agonists to the prostacyclin or β-adrenergic receptors. Although much has been learned about the role of the erythrocyte in perfusion of skeletal muscle, much remains to be understood. However, what is clear is that the long established passive carrier of O(2) also contributes to the regulation of the distribution of microvascular perfusion in skeletal muscle by virtue of its capacity to release ATP.
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Affiliation(s)
- Mary L Ellsworth
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, 1402 South Grand Boulevard, St Louis, MO 63104, USA.
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8
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Purinoceptor signaling in malaria-infected erythrocytes. Microbes Infect 2012; 14:779-86. [PMID: 22580091 DOI: 10.1016/j.micinf.2012.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Revised: 04/13/2012] [Accepted: 04/13/2012] [Indexed: 01/25/2023]
Abstract
Human erythrocytes are endowed with ATP release pathways and metabotropic and ionotropic purinoceptors. This review summarizes the pivotal function of purinergic signaling in erythrocyte control of vascular tone, in hemolytic septicemia, and in malaria. In malaria, the intraerythrocytic parasite exploits the purinergic signaling of its host to adapt the erythrocyte to its requirements.
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Sridharan M, Bowles EA, Richards JP, Krantic M, Davis KL, Dietrich KA, Stephenson AH, Ellsworth ML, Sprague RS. Prostacyclin receptor-mediated ATP release from erythrocytes requires the voltage-dependent anion channel. Am J Physiol Heart Circ Physiol 2011; 302:H553-9. [PMID: 22159995 DOI: 10.1152/ajpheart.00998.2011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Erythrocytes have been implicated as controllers of vascular caliber by virtue of their ability to release the vasodilator ATP in response to local physiological and pharmacological stimuli. The regulated release of ATP from erythrocytes requires activation of a signaling pathway involving G proteins (G(i) or G(s)), adenylyl cyclase, protein kinase A, and the cystic fibrosis transmembrane conductance regulator as well as a final conduit through which this highly charged anion exits the cell. Although pannexin 1 has been shown to be the final conduit for ATP release from human erythrocytes in response to reduced oxygen tension, it does not participate in transport of ATP following stimulation of the prostacyclin (IP) receptor in these cells, which suggests that an additional protein must be involved. Using antibodies directed against voltage-dependent anion channel (VDAC)1, we confirm that this protein is present in human erythrocyte membranes. To address the role of VDAC in ATP release, two structurally dissimilar VDAC inhibitors, Bcl-x(L) BH4(4-23) and TRO19622, were used. In response to the IP receptor agonists, iloprost and UT-15C, ATP release was inhibited by both VDAC inhibitors although neither iloprost-induced cAMP accumulation nor total intracellular ATP concentration were altered. Together, these findings support the hypothesis that VDAC is the ATP conduit in the IP receptor-mediated signaling pathway in human erythrocytes. In addition, neither the pannexin inhibitor carbenoxolone nor Bcl-x(L) BH4(4-23) attenuated ATP release in response to incubation of erythrocytes with the β-adrenergic receptor agonist isoproterenol, suggesting the presence of yet another channel for ATP release from human erythrocytes.
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Affiliation(s)
- Meera Sridharan
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, Saint Louis, Missouri, MO 63104, USA.
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Adderley SP, Thuet KM, Sridharan M, Bowles EA, Stephenson AH, Ellsworth ML, Sprague RS. Identification of cytosolic phosphodiesterases in the erythrocyte: a possible role for PDE5. Med Sci Monit 2011; 17:CR241-7. [PMID: 21525805 PMCID: PMC3366467 DOI: 10.12659/msm.881763] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background Within erythrocytes (RBCs), cAMP levels are regulated by phosphodiesterases (PDEs). Increases in cAMP and ATP release associated with activation of β-adrenergic receptors (βARs) and prostacyclin receptors (IPRs) are regulated by PDEs 2, 4 and PDE 3, respectively. Here we establish the presence of cytosolic PDEs in RBCs and determine a role for PDE5 in regulating levels of cGMP. Material/Methods Purified cytosolic proteins were obtained from isolated human RBCs and western analysis was performed using antibodies against PDEs 3A, 4 and 5. Rabbit RBCs were incubated with dbcGMP, a cGMP analog, to determine the effect of cGMP on cAMP levels. To determine if cGMP affects receptor-mediated increases in cAMP, rabbit RBCs were incubated with dbcGMP prior to addition of isoproterenol (ISO), a βAR receptor agonist. To demonstrate that endogenous cGMP produces the same effect, rabbit and human RBCs were incubated with SpNONOate (SpNO), a nitric oxide donor, and YC1, a direct activator of soluble guanylyl cyclase (sGC), in the absence and presence of a selective PDE5 inhibitor, zaprinast (ZAP). Results Western analysis identified PDEs 3A, 4D and 5A. dbcGMP produced a concentration dependent increase in cAMP and ISO-induced increases in cAMP were potentiated by dbcGMP. In addition, incubation with YC1 and SpNO in the presence of ZAP potentiated βAR-induced increases in cAMP. Conclusions PDEs 2, 3A and 5 are present in the cytosol of human RBCs. PDE5 activity in RBCs regulates cGMP levels. Increases in intracellular cGMP augment cAMP levels. These studies suggest a novel role for PDE5 in erythrocytes.
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Affiliation(s)
- Shaquria P Adderley
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO, USA.
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Impairment of the Plasmodium falciparum erythrocytic cycle induced by angiotensin peptides. PLoS One 2011; 6:e17174. [PMID: 21364758 PMCID: PMC3041794 DOI: 10.1371/journal.pone.0017174] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 01/21/2011] [Indexed: 12/30/2022] Open
Abstract
Plasmodium falciparum causes the most serious complications of malaria and is a public health problem worldwide with over 2 million deaths each year. The erythrocyte invasion mechanisms by Plasmodium sp. have been well described, however the physiological aspects involving host components in this process are still poorly understood. Here, we provide evidence for the role of renin-angiotensin system (RAS) components in reducing erythrocyte invasion by P. falciparum. Angiotensin II (Ang II) reduced erythrocyte invasion in an enriched schizont culture of P. falciparum in a dose-dependent manner. Using mass spectroscopy, we showed that Ang II was metabolized by erythrocytes to Ang IV and Ang-(1–7). Parasite infection decreased Ang-(1–7) and completely abolished Ang IV formation. Similar to Ang II, Ang-(1–7) decreased the level of infection in an A779 (specific antagonist of Ang-(1–7) receptor, MAS)-sensitive manner. 10−7 M PD123319, an AT2 receptor antagonist, partially reversed the effects of Ang-(1–7) and Ang II. However, 10−6 M losartan, an antagonist of the AT1 receptor, had no effect. Gs protein is a crucial player in the Plasmodium falciparum blood cycle and angiotensin peptides can modulate protein kinase A (PKA) activity; 10−8 M Ang II or 10−8 M Ang-(1–7) inhibited this activity in erythrocytes by 60% and this effect was reversed by 10−7 M A779. 10−6 M dibutyryl-cAMP increased the level of infection and 10−7 M PKA inhibitor decreased the level of infection by 30%. These results indicate that the effect of Ang-(1–7) on P. falciparum blood stage involves a MAS-mediated PKA inhibition. Our results indicate a crucial role for Ang II conversion into Ang-(1–7) in controlling the erythrocytic cycle of the malaria parasite, adding new functions to peptides initially described to be involved in the regulation of vascular tonus.
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Sridharan M, Adderley SP, Bowles EA, Egan TM, Stephenson AH, Ellsworth ML, Sprague RS. Pannexin 1 is the conduit for low oxygen tension-induced ATP release from human erythrocytes. Am J Physiol Heart Circ Physiol 2010; 299:H1146-52. [PMID: 20622111 DOI: 10.1152/ajpheart.00301.2010] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Erythrocytes release ATP in response to exposure to the physiological stimulus of lowered oxygen (O(2)) tension as well as pharmacological activation of the prostacyclin receptor (IPR). ATP release in response to these stimuli requires activation of adenylyl cyclase, accumulation of cAMP, and activation of protein kinase A. The mechanism by which ATP, a highly charged anion, exits the erythrocyte in response to lowered O(2) tension or receptor-mediated IPR activation by iloprost is unknown. It was demonstrated previously that inhibiting pannexin 1 with carbenoxolone inhibits hypotonically induced ATP release from human erythrocytes. Here we demonstrate that three structurally dissimilar compounds known to inhibit pannexin 1 prevent ATP release in response to lowered O(2) tension but not to iloprost-induced ATP release. These results suggest that pannexin 1 is the conduit for ATP release from erythrocytes in response to lowered O(2) tension. However, the identity of the conduit for iloprost-induced ATP release remains unknown.
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Affiliation(s)
- Meera Sridharan
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA.
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