The Experts below are selected from a list of 10476 Experts worldwide ranked by ideXlab platform
Yoshinori Moriyama - One of the best experts on this subject based on the ideXlab platform.
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Physiopathological roles of vesicular Nucleotide Transporter (VNUT), an essential component for vesicular ATP release.
Biochimica et biophysica acta. Biomembranes, 2020Co-Authors: Nao Hasuzawa, Yoshinori Moriyama, Sawako Moriyama, Masatoshi NomuraAbstract:Vesicular Nucleotide Transporter (VNUT) is the last identified member of the SLC17 organic anion Transporter family, which plays a central role in vesicular storage in ATP-secreting cells. The discovery of VNUT demonstrated that, despite having been neglected for a long time, vesicular ATP release represents a major pathway for purinergic chemical transmission, which had been mainly attributed to ATP permeation channels. This article summarizes recent advances in our understanding of the mechanism of VNUT and its physiopathological roles as well as the development of inhibitors. Regulating the activity and/or the expression of VNUT represents a new and promising therapeutic strategy for the treatment of multiple diseases.
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Vesicular Nucleotide Transporter mediates ATP release and migration in neutrophils
The Journal of biological chemistry, 2018Co-Authors: Yuika Harada, Yuri Kato, Takaaki Miyaji, Hiroshi Omote, Yoshinori Moriyama, Miki HiasaAbstract:Neutrophils migrate to sites infected by pathogenic microorganisms. This migration is regulated by neutrophil-secreted ATP, which stimulates neutrophils in an autocrine manner through purinergic receptors on the plasma membrane. Although previous studies have shown that ATP is released through channels at the plasma membrane of the neutrophil, it remains unknown whether it is also released through alternate secretory systems involving vesicular mechanisms. In this study, we investigated the possible involvement of vesicular Nucleotide Transporter (VNUT), a key molecule for vesicular storage and Nucleotide release, in ATP secretion from neutrophils. RT-PCR and Western blotting analysis indicated that VNUT is expressed in mouse neutrophils. Immunohistochemical analysis indicated that VNUT mainly colocalized with matrix metalloproteinase-9 (MMP-9), a marker of tertiary granules, which are secretory organelles. In mouse neutrophils, ATP release was inhibited by clodronate, which is a potent VNUT inhibitor. Furthermore, neutrophils from VNUT-/- mice did not release ATP and exhibited significantly reduced migration in vitro and in vivo These findings suggest that tertiary granule-localized VNUT is responsible for vesicular ATP release and subsequent neutrophil migration. Thus, these findings suggest an additional mechanism through which ATP is released by neutrophils.
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Clodronate: A Vesicular ATP Release Blocker
Trends in pharmacological sciences, 2017Co-Authors: Yoshinori Moriyama, Masatoshi NomuraAbstract:Clodronate is a first-generation bisphosphonate used worldwide for antiresorptive therapy for osteoporosis. Although clodronate is analgesic in nature, its mechanism and efficacy were unknown for some time. Recently, clodronate was identified as a selective and potent inhibitor for vesicular Nucleotide Transporter (VNUT), a Transporter responsible for vesicular storage of ATP. Clodronate inhibits vesicular ATP release from neurons and reduces chronic neuropathic and inflammatory pain following blockade of purinergic chemical transmission. Its effectiveness is stronger, faster acting, and longer lasting than that of existing drugs such as pregabalin. Thus, clodronate might be a promising drug for attenuating chronic neuropathic pain and opens a new field of drug discovery as a presynaptic blocker for purinergic chemical transmission.
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Vesicular Nucleotide Transporter (VNUT): appearance of an actress on the stage of purinergic signaling
Purinergic Signalling, 2017Co-Authors: Yoshinori Moriyama, Miki Hiasa, Hiroshi Omote, Shohei Sakamoto, Masatoshi NomuraAbstract:Vesicular storage of ATP is one of the processes initiating purinergic chemical transmission. Although an active transport mechanism was postulated to be involved in the processes, a Transporter(s) responsible for the vesicular storage of ATP remained unidentified for some time. In 2008, SLC17A9 , the last identified member of the solute carrier 17 type I inorganic phosphate Transporter family, was found to encode the vesicular Nucleotide Transporter (VNUT) that is responsible for the vesicular storage of ATP. VNUT transports various Nucleotides in a membrane potential-dependent fashion and is expressed in the various ATP-secreting cells. Mice with knockout of the VNUT gene lose vesicular storage and release of ATP from neurons and neuroendocrine cells, resulting in blockage of the initiation of purinergic chemical transmission. Thus, VNUT plays an essential role in the vesicular storage and release of ATP. The VNUT knockout mice exhibit resistance for neuropathic pain and a therapeutic effect against diabetes by way of increased insulin sensitivity. Thus, VNUT inhibitors and suppression of VNUT gene expression may be used for therapeutic purposes through suppression of purinergic chemical transmission. This review summarizes the studies to date on VNUT and discusses what we have learned about the relevance of vesicular ATP release as a potential drug target.
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Expression profile of vesicular Nucleotide Transporter (VNUT, SLC17A9) in subpopulations of rat dorsal root ganglion neurons.
Neuroscience letters, 2014Co-Authors: Kentaro Nishida, Yoshinori Moriyama, Yuka Nomura, Kanako Kawamori, Kazuki NagasawaAbstract:ATP plays an important role in the signal transduction between sensory neurons and satellite cells in dorsal root ganglia (DRGs). In primary cultured DRG neurons, ATP is known to be stored in lysosomes via a vesicular Nucleotide Transporter (VNUT), and to be released into the intercellular space through exocytosis. DRGs consist of large-, medium- and small-sized neurons, which play different roles in sensory transmission, but there is no information on the expression profiles of VNUT in DRG subpopulations. Here, we obtained detailed expression profiles of VNUT in isolated rat DRG tissues. On immunohistochemical analysis, VNUT was found in DRG neurons, and was predominantly expressed by the small- and medium-sized DRG ones, as judged upon visual inspection, and this was compatible with the finding that the number of VNUT-positive DRG neurons in IB4-positive cells was greater than that in NF200-positive ones. These results suggest that VNUT play a role in ATP accumulation in DRG neurons, especially in small- and medium-sized ones, and might be involved in ATP-mediated nociceptive signaling in DRGs.
Luigi Palmieri - One of the best experts on this subject based on the ideXlab platform.
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Identification and Characterization of ADNT1, a Novel Mitochondrial Adenine Nucleotide Transporter from Arabidopsis
Plant physiology, 2008Co-Authors: Luigi Palmieri, Antonella Santoro, Fernando Carrari, Emanuela Blanco, Adriano Nunes-nesi, Roberto Arrigoni, Francesco Genchi, Alisdair R. Fernie, Ferdinando PalmieriAbstract:Despite the fundamental importance and high level of compartmentation of mitochondrial Nucleotide metabolism in plants, our knowledge concerning the transport of Nucleotides across intracellular membranes remains far from complete. Study of a previously uncharacterized Arabidopsis (Arabidopsis thaliana) gene (At4g01100) revealed it to be a novel adenine Nucleotide Transporter, designated ADNT1, belonging to the mitochondrial carrier family. The ADNT1 gene shows broad expression at the organ level. Green fluorescent protein-based cell biological analysis demonstrated targeting of ADNT1 to mitochondria. While analysis of the expression of β-glucuronidase fusion proteins suggested that it was expressed across a broad range of tissue types, it was most highly expressed in root tips. Direct transport assays with recombinant and reconstituted ADNT1 were utilized to demonstrate that this protein displays a relatively narrow substrate specificity largely confined to adenylates and their closest analogs. ATP uptake was markedly inhibited by the presence of other adenylates and general inhibitors of mitochondrial transport but not by bongkrekate or carboxyatractyloside, inhibitors of the previously characterized ADP/ATP carrier. Furthermore, the kinetics are substantially different from those of this carrier, with ADNT1 preferring AMP to ADP. Finally, isolation and characterization of a T-DNA insertional knockout mutant of ADNT1, alongside complementation and antisense approaches, demonstrated that although deficiency of this Transporter did not seem to greatly alter photosynthetic metabolism, it did result in reduced root growth and respiration. These findings are discussed in the context of a potential function for ADNT1 in the provision of the energy required to support growth in heterotrophic plant tissues.
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The yeast peroxisomal adenine Nucleotide Transporter: characterization of two transport modes and involvement in DeltapH formation across peroxisomal membranes.
The Biochemical journal, 2004Co-Authors: Francesco M. Lasorsa, Ferdinando Palmieri, Hanspeter Rottensteiner, Pasquale Scarcia, Ralf Erdmann, Luigi PalmieriAbstract:The yeast peroxisomal adenine Nucleotide carrier, Ant1p, was shown to catalyse unidirectional transport in addition to exchange of substrates. In both transport modes, proton movement occurs. Nucleotide hetero-exchange is H+-compensated and electroneutral. Furthermore, microscopic fluorescence imaging of a pH-sensitive green fluorescent protein targeted to peroxisomes shows that Ant1p is involved in the formation of a DeltapH across the peroxisomal membrane, acidic inside.
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The yeast peroxisomal adenine Nucleotide Transporter: characterization of two transport modes and involvement in ΔpH formation across peroxisomal membranes
Biochemical Journal, 2004Co-Authors: Francesco M. Lasorsa, Ferdinando Palmieri, Hanspeter Rottensteiner, Pasquale Scarcia, Ralf Erdmann, Luigi PalmieriAbstract:The yeast peroxisomal adenine Nucleotide carrier, Ant1p, was shown to catalyse unidirectional transport in addition to exchange of substrates. In both transport modes, proton movement occurs. Nucleotide hetero-exchange is H+-compensated and electroneutral. Furthermore, microscopic fluorescence imaging of a pH-sensitive green fluorescent protein targeted to peroxisomes shows that Ant1p is involved in the formation of a DeltapH across the peroxisomal membrane, acidic inside.
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Identification and functional reconstitution of the yeast peroxisomal adenine Nucleotide Transporter.
The EMBO journal, 2001Co-Authors: Luigi Palmieri, Ferdinando Palmieri, Hanspeter Rottensteiner, Wolfgang Girzalsky, Pasquale Scarcia, Ralf ErdmannAbstract:The requirement for small molecule transport systems across the peroxisomal membrane has previously been postulated, but not directly proven. Here we report the identification and functional reconstitution of Ant1p (Ypr128cp), a peroxisomal Transporter in the yeast Saccharomyces cerevisiae, which has the characteristic sequence features of the mitochondrial carrier family. Ant1p was found to be an integral protein of the peroxisomal membrane and expression of ANT1 was oleic acid inducible. Targeting of Ant1p to peroxisomes was dependent on Pex3p and Pex19p, two peroxins specifically required for peroxisomal membrane protein insertion. Ant1p was essential for growth on medium-chain fatty acids as the sole carbon source. Upon reconstitution of the overexpressed and purified protein into liposomes, specific transport of adenine Nucleotides could be demonstrated. Remarkably, both the substrate and inhibitor specificity differed from those of the mitochondrial ADP/ATP Transporter. The physiological role of Ant1p in S.cerevisiae is probably to transport cytoplasmic ATP into the peroxisomal lumen in exchange for AMP generated in the activation of fatty acids.
M. Teresa Miras-portugal - One of the best experts on this subject based on the ideXlab platform.
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Live Imaging Reveals Cerebellar Neural Stem Cell Dynamics and the Role of VNUT in Lineage Progression
Stem cell reports, 2020Co-Authors: Lucía Paniagua-herranz, Aida Menéndez-méndez, Javier Gualix, Rosa Gómez-villafuertes, Esmerilda G. Delicado, Raquel Pérez-sen, Luis Alcides Olivos-oré, Miguel Biscaia, Antonio R. Artalejo, M. Teresa Miras-portugalAbstract:Summary Little is known about the intrinsic specification of postnatal cerebellar neural stem cells (NSCs) and to what extent they depend on information from their local niche. Here, we have used an adapted cell preparation of isolated postnatal NSCs and live imaging to demonstrate that cerebellar progenitors maintain their neurogenic nature by displaying hallmarks of NSCs. Furthermore, by using this preparation, all the cell types produced postnatally in the cerebellum, in similar relative proportions to those observed in vivo, can be monitored. The fact that neurogenesis occurs in such organized manner in the absence of signals from the local environment, suggests that cerebellar lineage progression is to an important extent governed by cell-intrinsic or pre-programmed events. Finally, we took advantage of the absence of the niche to assay the influence of the vesicular Nucleotide Transporter inhibition, which dramatically reduced the number of NSCs in vitro by promoting their progression toward neurogenesis.
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Physiopathological Role of the Vesicular Nucleotide Transporter (VNUT) in the Central Nervous System: Relevance of the Vesicular Nucleotide Release as a Potential Therapeutic Target.
Frontiers in cellular neuroscience, 2019Co-Authors: M. Teresa Miras-portugal, Aida Menéndez-méndez, Felipe Ortega, Rosa Gómez-villafuertes, Esmerilda G. Delicado, Raquel Pérez-sen, Javier GualixAbstract:Vesicular storage of neurotransmitters, which allows their subsequent exocytotic release, is essential for chemical transmission in the central nervous system. Neurotransmitter uptake into secretory vesicles is carried out by vesicular Transporters, which use the electrochemical proton gradient generated by a vacuolar H+-ATPase to drive neurotransmitter vesicular accumulation. ATP and other Nucleotides are relevant extracellular signaling molecules that participate in a variety of biological processes. Although the active transport of Nucleotides into secretory vesicles has been characterized from the pharmacological and biochemical point of view, the protein responsible for such vesicular accumulation remained unidentified for some time. In 2008, the human SLC17A9 gene, the last identified member of the SLC17 Transporters, was found to encode the vesicular Nucleotide Transporter (VNUT). VNUT is expressed in various ATP-secreting cells and is able to transport a wide variety of Nucleotides in a vesicular membrane potential-dependent manner. VNUT knockout mice lack vesicular storage and release of ATP, resulting in blockage of the purinergic transmission. This review summarizes the current studies on VNUT and analyzes the physiological relevance of the vesicular Nucleotide transport in the central nervous system. The possible role of VNUT in the development of some pathological processes, such as chronic neuropathic pain or glaucoma is also discussed. The putative involvement of VNUT in these pathologies raises the possibility of the use of VNUT inhibitors for therapeutic purposes.
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Specific Temporal Distribution and Subcellular Localization of a Functional Vesicular Nucleotide Transporter (VNUT) in Cerebellar Granule Neurons.
Frontiers in pharmacology, 2017Co-Authors: Aida Menéndez-méndez, Juan Ignacio Díaz-hernández, Felipe Ortega, Javier Gualix, Rosa Gómez-villafuertes, M. Teresa Miras-portugalAbstract:ATP is an important extracellular neurotransmitter that participates in several critical processes like cell differentiation, neuroprotection or axon guidance. Prior to its exocytosis, ATP must be stored in secretory vesicles, a process that is mediated by the Vesicular Nucleotide Transporter (VNUT). This Transporter has been identified as the product of the SLC17A9 gene and it is prominently expressed in discrete brain areas, including the cerebellum. The main population of cerebellar neurons, the glutamatergic granule neurons, depends on purinergic signaling to trigger neuroprotective responses. However, while Nucleotide receptors like P2X7 and P2Y13 are known to be involved in neuroprotection, the mechanisms that regulate ATP release in relation to such events are less clearly understood. In this work, we demonstrate that cerebellar granule cells express a functional VNUT that is involved in the regulation of ATP exocytosis. Numerous vesicles loaded with this Nucleotide can be detected in these granule cells and are staining by the fluorescent ATP-marker, quinacrine. High potassium stimulation reduces quinacrine fluorescence in granule cells, indicating they release ATP via calcium dependent exocytosis. Specific subcellular markers were used to assess the localization of VNUT in granule cells, and the Transporter was detected in both the axonal and somatodendritic compartments, most predominantly in the latter. However, co-localization with the specific lysosomal marker LAMP-1 indicated that VNUT can also be found in non-synaptic vesicles, such as lysosomes. Interestingly, the weak co-localization between VNUT and VGLUT1 suggests that the ATP and glutamate vesicle pools are segregated, as also observed in the cerebellar cortex. During post-natal cerebellar development, VNUT is found in granule cell precursors, co-localizing with markers of immature cells like doublecortin, suggesting that this Transporter may be implicated in the initial stages of granule cell development.
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Increased levels of extracellular ATP in glaucomatous retinas: Possible role of the vesicular Nucleotide Transporter during the development of the pathology.
Molecular vision, 2015Co-Authors: María J. Pérez De Lara, Juan Ignacio Díaz-hernández, M. Teresa Miras-portugal, Ana Guzman-aranguez, Pedro De La Villa, Jesús PintorAbstract:Purpose: To study retinal extracellular ATP levels and to assess the changes in the vesicular Nucleotide Transporter (VNUT) expression in a murine model of glaucoma during the development of the disease. Methods: Retinas were obtained from glaucomatous DBA/2J mice at 3, 9, 15, and 22 months together with C57BL/6J mice used as age-matched controls. To study retinal Nucleotide release, the retinas were dissected and prepared as flattened whole mounts and stimulated in Ringer buffer with or without 59 mM KCl. To investigate VNUT expression, sections of the mouse retinas were evaluated with immunohistochemistry and western blot analysis using newly developed antibodies against VNUT. All images were examined and photographed under confocal microscopy. Electroretinogram (ERG) recordings were performed on the C57BL/6J and DBA/2J mice to analyze the changes in the electrophysiological response; a decrease in the scotopic threshold response was observed in the 15-month-old DBA/2J mice. Results: In the 15-month-old control and glaucomatous mice, electrophysiological changes of 42% were observed. In addition, 50% increases in the intraocular pressure (IOP) were observed when the pathology was fully established. The responses in the retinal ATP net release as the pathology progressed varied from 0.32±0.04 pmol/retina (3 months) to 1.10±0.06 pmol/retina (15 months; threefold increase). Concomitantly, VNUT expression was significantly increased during glaucoma progression in the DBA/2J mice (58%) according to the immunohistochemical and western blot analysis. Conclusions: These results may indicate a possible correlation between retinal dysfunction and increased levels of extracellular ATP and Nucleotide Transporter. These data support an excitotoxicity role for ATP via P2X7R in glaucoma. This modified cellular environment could contribute to explaining the functional and biochemical alterations observed during the development of the pathology.
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The vesicular Nucleotide Transporter (VNUT) is involved in the extracellular ATP effect on neuronal differentiation
Purinergic Signalling, 2015Co-Authors: Aida Menéndez-méndez, Juan Ignacio Díaz-hernández, M. Teresa Miras-portugalAbstract:Before being released, Nucleotides are stored in secretory vesicles through the vesicular Nucleotide Transporter (VNUT). Once released, extracellular ATP participates in neuronal differentiation processes. Thus, the expression of a functional VNUT could be an additional component of the purinergic system which regulates neuronal differentiation and axonal elongation. In vitro expression of VNUT decreases neuritogenesis in N2a cells differentiated by retinoic acid treatment, whereas silencing of VNUT expression increases the number and length of neurites in these cells. These results highlight the role of VNUT in the neuritogenic process because this Transporter regulates the ATP content in neurosecretory vesicles.
Miki Hiasa - One of the best experts on this subject based on the ideXlab platform.
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Anti-Depressant Fluoxetine Reveals its Therapeutic Effect Via Astrocytes.
EBioMedicine, 2018Co-Authors: Manao Kinoshita, Yuri Hirayama, Kayoko Fujishita, Keisuke Shibata, Youichi Shinozaki, Eiji Shigetomi, Akiko Takeda, Hideaki Hayashi, Miki HiasaAbstract:Although psychotropic drugs act on neurons and glial cells, how glia respond, and whether glial responses are involved in therapeutic effects are poorly understood. Here, we show that fluoxetine (FLX), an anti-depressant, mediates its anti-depressive effect by increasing the gliotransmission of ATP. FLX increased ATP exocytosis via vesicular Nucleotide Transporter (VNUT). FLX-induced anti-depressive behavior was decreased in astrocyte-selective VNUT-knockout mice or when VNUT was deleted in mice, but it was increased when astrocyte-selective VNUT was overexpressed in mice. This suggests that VNUT-dependent astrocytic ATP exocytosis has a critical role in the therapeutic effect of FLX. Released ATP and its metabolite adenosine act on P2Y11 and adenosine A2b receptors expressed by astrocytes, causing an increase in brain-derived neurotrophic factor in astrocytes. These findings suggest that in addition to neurons, FLX acts on astrocytes and mediates its therapeutic effects by increasing ATP gliotransmission.
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Vesicular Nucleotide Transporter mediates ATP release and migration in neutrophils
The Journal of biological chemistry, 2018Co-Authors: Yuika Harada, Yuri Kato, Takaaki Miyaji, Hiroshi Omote, Yoshinori Moriyama, Miki HiasaAbstract:Neutrophils migrate to sites infected by pathogenic microorganisms. This migration is regulated by neutrophil-secreted ATP, which stimulates neutrophils in an autocrine manner through purinergic receptors on the plasma membrane. Although previous studies have shown that ATP is released through channels at the plasma membrane of the neutrophil, it remains unknown whether it is also released through alternate secretory systems involving vesicular mechanisms. In this study, we investigated the possible involvement of vesicular Nucleotide Transporter (VNUT), a key molecule for vesicular storage and Nucleotide release, in ATP secretion from neutrophils. RT-PCR and Western blotting analysis indicated that VNUT is expressed in mouse neutrophils. Immunohistochemical analysis indicated that VNUT mainly colocalized with matrix metalloproteinase-9 (MMP-9), a marker of tertiary granules, which are secretory organelles. In mouse neutrophils, ATP release was inhibited by clodronate, which is a potent VNUT inhibitor. Furthermore, neutrophils from VNUT-/- mice did not release ATP and exhibited significantly reduced migration in vitro and in vivo These findings suggest that tertiary granule-localized VNUT is responsible for vesicular ATP release and subsequent neutrophil migration. Thus, these findings suggest an additional mechanism through which ATP is released by neutrophils.
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Vesicular Nucleotide Transporter (VNUT): appearance of an actress on the stage of purinergic signaling
Purinergic Signalling, 2017Co-Authors: Yoshinori Moriyama, Miki Hiasa, Hiroshi Omote, Shohei Sakamoto, Masatoshi NomuraAbstract:Vesicular storage of ATP is one of the processes initiating purinergic chemical transmission. Although an active transport mechanism was postulated to be involved in the processes, a Transporter(s) responsible for the vesicular storage of ATP remained unidentified for some time. In 2008, SLC17A9 , the last identified member of the solute carrier 17 type I inorganic phosphate Transporter family, was found to encode the vesicular Nucleotide Transporter (VNUT) that is responsible for the vesicular storage of ATP. VNUT transports various Nucleotides in a membrane potential-dependent fashion and is expressed in the various ATP-secreting cells. Mice with knockout of the VNUT gene lose vesicular storage and release of ATP from neurons and neuroendocrine cells, resulting in blockage of the initiation of purinergic chemical transmission. Thus, VNUT plays an essential role in the vesicular storage and release of ATP. The VNUT knockout mice exhibit resistance for neuropathic pain and a therapeutic effect against diabetes by way of increased insulin sensitivity. Thus, VNUT inhibitors and suppression of VNUT gene expression may be used for therapeutic purposes through suppression of purinergic chemical transmission. This review summarizes the studies to date on VNUT and discusses what we have learned about the relevance of vesicular ATP release as a potential drug target.
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identification of a vesicular atp release inhibitor for the treatment of neuropathic and inflammatory pain
Proceedings of the National Academy of Sciences of the United States of America, 2017Co-Authors: Yuri Kato, Miki Hiasa, Reiko Ichikawa, Nao Hasuzawa, Atsushi Kadowaki, Ken Iwatsuki, Kazuhiro Shima, Yasuo Endo, Yoshiro KitaharaAbstract:Despite the high incidence of neuropathic and inflammatory pain worldwide, effective drugs with few side effects are currently unavailable for the treatment of chronic pain. Recently, researchers have proposed that inhibitors of purinergic chemical transmission, which plays a key role in the pathological pain response, may allow for targeted treatment of pathological neuropathic and inflammatory pain. However, such therapeutic analgesic agents have yet to be developed. In the present study, we demonstrated that clodronate, a first-generation bisphosphonate with comparatively fewer side effects than traditional treatments, significantly attenuates neuropathic and inflammatory pain unrelated to bone abnormalities via inhibition of vesicular Nucleotide Transporter (VNUT), a key molecule for the initiation of purinergic chemical transmission. In vitro analyses indicated that clodronate inhibits VNUT at a half-maximal inhibitory concentration of 15.6 nM without affecting other vesicular neurotransmitter Transporters, acting as an allosteric modulator through competition with Cl−. A low concentration of clodronate impaired vesicular ATP release from neurons, microglia, and immune cells. In vivo analyses revealed that clodronate is more effective than other therapeutic agents in attenuating neuropathic and inflammatory pain, as well as the accompanying inflammation, in wild-type but not VNUT−/− mice, without affecting basal nociception. These findings indicate that clodronate may represent a unique treatment strategy for chronic neuropathic and inflammatory pain via inhibition of vesicular ATP release.
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Expression of Vesicular Nucleotide Transporter in the Mouse Retina.
Biological & pharmaceutical bulletin, 2016Co-Authors: Satomi Moriyama, Miki HiasaAbstract:Vesicular Nucleotide Transporter (VNUT) is a membrane protein that is responsible for vesicular storage and subsequent vesicular release of Nucleotides, such as ATP, and plays an essential role in purinergic chemical transmission. In the present study, we investigated whether VNUT is present in the rodent retina to define the site(s) of vesicular ATP release. In the mouse retina, reverse transcription polymerase chain reaction (RT-PCR) and immunological analyses using specific anti-VNUT antibodies indicated that VNUT is expressed as a polypeptide with an apparent molecular mass of 59 kDa. VNUT is widely distributed throughout the inner and outer retinal layers, particularly in the outer segment of photoreceptors, outer plexiform layer, inner plexiform layer, and ganglion cell layer. VNUT is colocalized with vesicular glutamate Transporter 1 and synaptophysin in photoreceptor cells, while it is colocalized with vesicular γ-aminobutyric acid (GABA) Transporter in amacrine cells and bipolar cells. VNUT is also present in astrocytes and Muller cells. The retina from VNUT knockout (VNUT(-/-)) mice showed the loss of VNUT immunoreactivity. The retinal membrane fraction took up radiolabeled ATP in diisothiocyanate stilbene disulfonic acid (DIDS)-, an inhibitor of VNUT, and bafilomycin A1-, a vacuolar adenosine triphosphatase (ATPase) inhibitor, in a sensitive manner, while membranes from VNUT(-/-) mice showed the loss of DIDS-sensitive ATP uptake. Taken together, these results indicate that functional VNUT is expressed in the rodent retina and suggest that ATP is released from photoreceptor cells, bipolar cells, amacrine cells, and astrocytes as well as Muller cells to initiate purinergic chemical transmission.
Ferdinando Palmieri - One of the best experts on this subject based on the ideXlab platform.
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Identification and Characterization of ADNT1, a Novel Mitochondrial Adenine Nucleotide Transporter from Arabidopsis
Plant physiology, 2008Co-Authors: Luigi Palmieri, Antonella Santoro, Fernando Carrari, Emanuela Blanco, Adriano Nunes-nesi, Roberto Arrigoni, Francesco Genchi, Alisdair R. Fernie, Ferdinando PalmieriAbstract:Despite the fundamental importance and high level of compartmentation of mitochondrial Nucleotide metabolism in plants, our knowledge concerning the transport of Nucleotides across intracellular membranes remains far from complete. Study of a previously uncharacterized Arabidopsis (Arabidopsis thaliana) gene (At4g01100) revealed it to be a novel adenine Nucleotide Transporter, designated ADNT1, belonging to the mitochondrial carrier family. The ADNT1 gene shows broad expression at the organ level. Green fluorescent protein-based cell biological analysis demonstrated targeting of ADNT1 to mitochondria. While analysis of the expression of β-glucuronidase fusion proteins suggested that it was expressed across a broad range of tissue types, it was most highly expressed in root tips. Direct transport assays with recombinant and reconstituted ADNT1 were utilized to demonstrate that this protein displays a relatively narrow substrate specificity largely confined to adenylates and their closest analogs. ATP uptake was markedly inhibited by the presence of other adenylates and general inhibitors of mitochondrial transport but not by bongkrekate or carboxyatractyloside, inhibitors of the previously characterized ADP/ATP carrier. Furthermore, the kinetics are substantially different from those of this carrier, with ADNT1 preferring AMP to ADP. Finally, isolation and characterization of a T-DNA insertional knockout mutant of ADNT1, alongside complementation and antisense approaches, demonstrated that although deficiency of this Transporter did not seem to greatly alter photosynthetic metabolism, it did result in reduced root growth and respiration. These findings are discussed in the context of a potential function for ADNT1 in the provision of the energy required to support growth in heterotrophic plant tissues.
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The yeast peroxisomal adenine Nucleotide Transporter: characterization of two transport modes and involvement in DeltapH formation across peroxisomal membranes.
The Biochemical journal, 2004Co-Authors: Francesco M. Lasorsa, Ferdinando Palmieri, Hanspeter Rottensteiner, Pasquale Scarcia, Ralf Erdmann, Luigi PalmieriAbstract:The yeast peroxisomal adenine Nucleotide carrier, Ant1p, was shown to catalyse unidirectional transport in addition to exchange of substrates. In both transport modes, proton movement occurs. Nucleotide hetero-exchange is H+-compensated and electroneutral. Furthermore, microscopic fluorescence imaging of a pH-sensitive green fluorescent protein targeted to peroxisomes shows that Ant1p is involved in the formation of a DeltapH across the peroxisomal membrane, acidic inside.
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The yeast peroxisomal adenine Nucleotide Transporter: characterization of two transport modes and involvement in ΔpH formation across peroxisomal membranes
Biochemical Journal, 2004Co-Authors: Francesco M. Lasorsa, Ferdinando Palmieri, Hanspeter Rottensteiner, Pasquale Scarcia, Ralf Erdmann, Luigi PalmieriAbstract:The yeast peroxisomal adenine Nucleotide carrier, Ant1p, was shown to catalyse unidirectional transport in addition to exchange of substrates. In both transport modes, proton movement occurs. Nucleotide hetero-exchange is H+-compensated and electroneutral. Furthermore, microscopic fluorescence imaging of a pH-sensitive green fluorescent protein targeted to peroxisomes shows that Ant1p is involved in the formation of a DeltapH across the peroxisomal membrane, acidic inside.
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Identification and functional reconstitution of the yeast peroxisomal adenine Nucleotide Transporter.
The EMBO journal, 2001Co-Authors: Luigi Palmieri, Ferdinando Palmieri, Hanspeter Rottensteiner, Wolfgang Girzalsky, Pasquale Scarcia, Ralf ErdmannAbstract:The requirement for small molecule transport systems across the peroxisomal membrane has previously been postulated, but not directly proven. Here we report the identification and functional reconstitution of Ant1p (Ypr128cp), a peroxisomal Transporter in the yeast Saccharomyces cerevisiae, which has the characteristic sequence features of the mitochondrial carrier family. Ant1p was found to be an integral protein of the peroxisomal membrane and expression of ANT1 was oleic acid inducible. Targeting of Ant1p to peroxisomes was dependent on Pex3p and Pex19p, two peroxins specifically required for peroxisomal membrane protein insertion. Ant1p was essential for growth on medium-chain fatty acids as the sole carbon source. Upon reconstitution of the overexpressed and purified protein into liposomes, specific transport of adenine Nucleotides could be demonstrated. Remarkably, both the substrate and inhibitor specificity differed from those of the mitochondrial ADP/ATP Transporter. The physiological role of Ant1p in S.cerevisiae is probably to transport cytoplasmic ATP into the peroxisomal lumen in exchange for AMP generated in the activation of fatty acids.
