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Silva HAMF, Aires AL, Soares CLR, Siqueira WN, Lima MV, Martins MCB, Albuquerque MCPA, Silva TG, Brayner FA, Alves LC, Melo AMMA, Silva NH. Schistosomicidal effect of divaricatic acid from Canoparmelia texana (Lichen): In vitro evaluation and ultrastructural analysis against adult worms of Schistosoma mansoni. Acta Trop 2021; 222:106044. [PMID: 34273313 DOI: 10.1016/j.actatropica.2021.106044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 06/16/2021] [Accepted: 07/08/2021] [Indexed: 11/29/2022]
Abstract
In this study we evaluated the in vitro effect of divaricatic acid against coupled worms of Schistosoma mansoni. The schistosomicidal effect was evaluated through the bioassay of motility and mortality, cellular viability of the worms and ultrastructural analysis through Scanning Electron Microscopy. To evaluate the cytotoxicity of divaricatic acid, a cell viability assay was performed with human peripheral blood mononuclear cells. Divaricatic acid proved effect against S. mansoni after 3 hours of exposure. At the end of 24 h the concentrations of 100 - 200 μM presented lethality to the worms. Motility changes were observed at sublethal concentrations. The IC50 obtained by the cell viability assay for S. mansoni was 100.6 μM (96.24 - 105.2 μM). Extensive damage to the worm's tegument was observed such as peeling, erosion, bubbles, edema, damage and loss of tubercles and spines, fissures and tissue ruptures. No cytotoxicity was observed in human peripheral blood mononuclear cells. This report provides data showing the schistosomicidal effect of divaricatic acid on S. mansoni, causing death, motile changes and ultrastructural damage to worms. In addition, divaricatic acid was shown to be non-toxic to human peripheral blood mononuclear cells at concentrations effective on S. mansoni.
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Affiliation(s)
- Hianna A M F Silva
- Departamento de Bioquímica, Centro de Biociências, Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil; Departamento de Biofísica e Radiobiologia, Centro de Biociência, Universidade Federal de Pernambuco, Avenida Prof. Artur de Sá, s/n, Cidade Universitária. CEP 54740-520, Recife, PE, Brazil.
| | - André L Aires
- Departamento de Medicina Tropical, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, s/n, Cidade Universitária, 50740-600, Recife, PE, Brazil; Laboratório de Imunopatologia Keizo Asami (LIKA), Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil
| | - Caroline L R Soares
- Departamento de Antibióticos, Centro de Biociência, Universidade Federal de Pernambuco, Avenida Prof. Artur de Sá, s/n, Cidade Universitária. CEP 54740-520, Recife, PE, Brazil
| | - Williams N Siqueira
- Departamento de Biofísica e Radiobiologia, Centro de Biociência, Universidade Federal de Pernambuco, Avenida Prof. Artur de Sá, s/n, Cidade Universitária. CEP 54740-520, Recife, PE, Brazil; Departamento de Energia Nuclear, Centro de Tecnologia e Geociências, Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil
| | - Maíra V Lima
- Departamento de Biofísica e Radiobiologia, Centro de Biociência, Universidade Federal de Pernambuco, Avenida Prof. Artur de Sá, s/n, Cidade Universitária. CEP 54740-520, Recife, PE, Brazil; Departamento de Energia Nuclear, Centro de Tecnologia e Geociências, Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil
| | - Mônica C B Martins
- Departamento de Bioquímica, Centro de Biociências, Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil
| | - Mônica C P A Albuquerque
- Departamento de Medicina Tropical, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, s/n, Cidade Universitária, 50740-600, Recife, PE, Brazil; Laboratório de Imunopatologia Keizo Asami (LIKA), Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil
| | - Teresinha G Silva
- Departamento de Antibióticos, Centro de Biociência, Universidade Federal de Pernambuco, Avenida Prof. Artur de Sá, s/n, Cidade Universitária. CEP 54740-520, Recife, PE, Brazil
| | - Fábio A Brayner
- Laboratório de Imunopatologia Keizo Asami (LIKA), Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil; Departamento de Parasitologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil
| | - Luiz C Alves
- Laboratório de Imunopatologia Keizo Asami (LIKA), Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil; Departamento de Parasitologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil
| | - Ana M M A Melo
- Departamento de Biofísica e Radiobiologia, Centro de Biociência, Universidade Federal de Pernambuco, Avenida Prof. Artur de Sá, s/n, Cidade Universitária. CEP 54740-520, Recife, PE, Brazil; Departamento de Energia Nuclear, Centro de Tecnologia e Geociências, Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil
| | - Nicácio H Silva
- Departamento de Bioquímica, Centro de Biociências, Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária. CEP 50.670-901, Recife, PE, Brazil
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Abou-El-Naga IF. Schistosoma mansoni sarco/endoplasmic reticulum Ca2+ ATPases (SERCA): role in reduced sensitivity to praziquantel. J Bioenerg Biomembr 2020; 52:397-408. [DOI: 10.1007/s10863-020-09843-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 06/08/2020] [Indexed: 01/17/2023]
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3
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Thapsigargins and induced chemical defence in Thapsia garganica. CHEMOECOLOGY 2020. [DOI: 10.1007/s00049-020-00315-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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4
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Calcium and Ca 2+/Calmodulin-dependent kinase II as targets for helminth parasite control. Biochem Soc Trans 2018; 46:1743-1751. [PMID: 30420417 DOI: 10.1042/bst20180480] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/07/2018] [Accepted: 10/01/2018] [Indexed: 11/17/2022]
Abstract
In eukaryotes, effective calcium homeostasis is critical for many key biological processes. There is an added level of complexity in parasites, particularly multicellular helminth worms, which modulate calcium levels while inhabiting the host microenvironment. Parasites ensure efficient calcium homeostasis through gene products, such as the calmodulin-dependent kinases (CaMK), the main focus of this review. The importance of CaMK is becoming increasingly apparent from recent functional studies of helminth and protozoan parasites. Investigations on the molecular regulation of calcium and the role of CaMK are important for both supplementing current drug regimens and finding new antiparasitic compounds. Whereas calcium regulators, including CaMK, are well characterised in mammalian systems, knowledge of their functional properties in parasites is increasing but is still in its infancy.
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Abstract
Cyclopiazonic acid (CPA) is an indol-tetramic acid mycotoxin and is produced by the nearly ubiquitous molds, Aspergillus and Penicillium. CPA produced by these molds has been identified in a number of food sources (including, but not limited to, grain, legumes, meat, milk, and cheese) and from parasitic infections of man and other animals. Few incidents of CPA mycotoxicoses have been reported because of the benign nature of the intoxication, the small amounts present, and its effects may be disguised with concurrent aflatoxicosis (some toxicity data may have been generated using aflatoxin-contaminated CPA). CPA is absorbed in the gastrointestinal tract and following oral administration; it has a half-life of approximately 30 hours and is excreted largely unchanged in the urine and feces. Cyclopiazonic acid is not considered to be a potent acute toxin as its oral LD50 in rodents is in the range of 30 to 70 mg/kg. Multiple dose studies also show a range of effects in several species and among mammalian models, the pig appears to be the most sensitive with a no-observable-effect level (NOEL) in the range of 1.0 mg/kg/day. The preponderance of evidence from the rat and other test animals supports this dose as a defensible estimate of a no effect level. The target organs of CPA toxicity appear to be muscle, hepatic tissue, and spleen, with a localization in the former, although a more apparent toxic change in the latter two. The toxicity and symptoms of CPA poisoning can be attributed to its ability to alter normal intracellular calcium flux through its inhibition of the reticular form of the Ca2+-ATPase pump. CPA was not teratogenic in mice. CPA is not considered a carcinogen and the weight of evidence militates against its characterization as a mutagen. Despite CPA-induced pathological changes ascribed to the spleen or bursa of Fabricius, there does not appear to be an effect on the immune system. In vitro studies imply a potential immunomodulatory effect of CPA, but in all of those reports very high concentrations of CPA were required and none of these findings have been supported with in vivo studies. Therefore, based on a NOEL of 1 mg/kg/day and accounting for species variation, an appropriate acceptable daily intake (ADI) would be approximately 10 μg/kg/day or 700 μg/day. In the context of human exposure, if the uppermost limit of CPA found in cheese is 4 μg/g and the average individual consumes 50 g of cheese daily, this allows an intake of 200 μg, less than one third of a traditionally established ADI.
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Affiliation(s)
- G. A. Burdock
- Burdock and Associates, Inc., Vero Beach, Florida, USA
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Lepore R, Simeoni S, Raimondo D, Caroli A, Tramontano A, Via A. Identification of the Schistosoma mansoni molecular target for the antimalarial drug artemether. J Chem Inf Model 2011; 51:3005-16. [PMID: 21995318 DOI: 10.1021/ci2001764] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Plasmodium falciparum and Schistosoma mansonii are the parasites responsible for most of the malaria and schistosomiasis cases in the world. Notwithstanding their many differences, the two agents have striking similarities in that they both are blood feeders and are targets of an overlapping set of drugs, including the well-known artemether molecule. Here we explore the possibility of using the known information about the mode of action of artemether in Plasmodium to identify the molecular target of the drug in Schistosoma and provide evidence that artemether binds to SmSERCA, a putative Ca²⁺-ATPase of Schistosoma . We also predict the putative binding mode of the molecule for both its Plasmodium and Schistosoma targets. Our analysis of the mode of binding of artemether to Ca²⁺-ATPases also provides an explanation for the apparent paradox that, although the molecule has no side effect in humans, it has been shown to possess antitumoral activity.
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Affiliation(s)
- Rosalba Lepore
- Department of Physics, Sapienza University of Rome, Rome, Italy
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7
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Greenberg RM. Ca2+ signalling, voltage-gated Ca2+ channels and praziquantel in flatworm neuromusculature. Parasitology 2007; 131 Suppl:S97-108. [PMID: 16569296 DOI: 10.1017/s0031182005008346] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Transient changes in calcium (Ca2+) levels regulate a wide variety of cellular processes, and cells employ both intracellular and extracellular sources of Ca2+ for signalling. Praziquantel, the drug of choice against schistosomiasis, disrupts Ca2+ homeostasis in adult worms. This review will focus on voltage-gated Ca2+ channels, which regulate levels of intracellular Ca2+ by coupling membrane depolarization to entry of extracellular Ca2+. Ca2+ channels are members of the ion channel superfamily and represent essential components of neurons, muscles and other excitable cells. Ca2+ channels are membrane protein complexes in which the pore-forming alpha1 subunit is modulated by auxiliary subunits such as beta and alpha2delta. Schistosomes express two Ca2+ channel beta subunit subtypes: a conventional subtype similar to beta subunits found in other vertebrates and invertebrates and a novel variant subtype with unusual structural and functional properties. The variant schistosome beta subunit confers praziquantel sensitivity to an otherwise praziquantel-insensitive mammalian Ca2+ channel, implicating it as a mediator of praziquantel action.
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Affiliation(s)
- R M Greenberg
- Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543, USA.
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8
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Sengupta T, Ghoshal S, Sen PC. Stimulation of Mg2+-independent form of Ca2+-ATPase by a low molecular mass protein purified from goat testes cytosol. Comp Biochem Physiol B Biochem Mol Biol 2007; 146:131-8. [PMID: 17126581 DOI: 10.1016/j.cbpb.2006.10.093] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 09/15/2006] [Accepted: 10/10/2006] [Indexed: 11/22/2022]
Abstract
A low molecular mass protein purified from goat (Capra hircus) testes cytosol following gel filtration and anion exchange chromatographic separation stimulates Mg(2+)-independent Ca(2+)-ATPase activity without any significant effect on Mg(2+)-dependent Ca(2+)-ATPase. Stimulation of the ATPase is due to an increase in the rate of dephosphorylation of the overall reaction step of the enzyme. Binding of the stimulator increases the affinity of Ca(2+)-ATPase for Ca(2+). An analysis of enzyme kinetics reveals a reversible type of binding of the stimulator to the ATPase and non-competitive type of stimulation with respect to the substrate. Stimulation seems due to binding of the protein at a single site following Michaelis-Menten model. The protein can also counter the effect of calcium antagonists exerted on the ATPase. The pI of the protein is 6.2 and its molecular mass has been determined to be 13, 961 by Q-TOF-MS.
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Mendonça-Silva DL, Novozhilova E, Cobbett PJR, Silva CLM, Noël F, Totten MIJ, Maule AG, Day TA. Role of calcium influx through voltage-operated calcium channels and of calcium mobilization in the physiology of Schistosoma mansoni muscle contractions. Parasitology 2006; 133:67-74. [PMID: 16566851 DOI: 10.1017/s0031182006000023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 12/22/2005] [Accepted: 12/23/2005] [Indexed: 11/07/2022]
Abstract
We tested the hypothesis that voltage-operated Ca2+ channels mediate an extracellular Ca2+ influx in muscle fibres from the human parasite Schistosoma mansoni and, along with Ca2+ mobilization from the sarcoplasmic reticulum, contribute to muscle contraction. Indeed, whole-cell voltage clamp revealed voltage-gated inward currents carried by divalent ions with a peak current elicited by steps to +20 mV (from a holding potential of -70 mV). Depolarization of the fibres by elevated extracellular K+ elicited contractions that were completely dependent on extracellular Ca2+ and inhibited by nicardipine (half inhibition at 4.1 microM). However these contractions were not very sensitive to other classical blockers of voltage-gated Ca2+ channels, indicating that the schistosome muscle channels have an atypical pharmacology when compared to their mammalian counterparts. Futhermore, the contraction induced by 5 mM caffeine was inhibited after depletion of the sarcoplasmic reticulum either with thapsigargin (10 microM) or ryanodine (10 microM). These data suggest that voltage-operated Ca2+ channels do contribute to S. mansoni contraction as does the mobilization of stored Ca2+, despite the small volume of sarcoplasmic reticulum in schistosome smooth muscles.
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Affiliation(s)
- D L Mendonça-Silva
- Departamento de Farmacologia Básica e Clínica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Brazil
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10
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Quintas LEM, Cunha VMN, Scaramello CBV, da Silva CLM, Caricati-Neto A, Lafayette SSL, Jurkiewicz A, Noël F. Adaptive expression pattern of different proteins involved in cellular calcium homeostasis in denervated rat vas deferens. Eur J Pharmacol 2005; 525:54-9. [PMID: 16289527 DOI: 10.1016/j.ejphar.2005.10.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Revised: 08/23/2005] [Accepted: 10/07/2005] [Indexed: 11/15/2022]
Abstract
The activity and protein expression of plasma membrane and sarco(endo)plasmic reticulum (Ca2+-Mg2+)ATPases and ryanodine receptors were investigated in surgically denervated rat vas deferens. The function of thapsigargin-sensitive but not thapsigargin-resistant (Ca2+-Mg2+)ATPase (from sarco(endo)plasmic reticulum and plasma membrane, respectively), evidenced by enzyme activity and Ca2+ uptake experiments, was significantly depressed by 30-50% when compared to innervated vas. Western blots showed that such reduction in sarco(endo)plasmic reticulum (Ca2+-Mg2+)ATPase performance was accompanied by a decrement of similar magnitude in sarco(endo)plasmic reticulum (Ca2+-Mg2+)ATPase type 2 protein expression, without any significant change in plasma membrane (Ca2+-Mg2+)ATPase expression. Finally, [3H]ryanodine binding revealed that the density of ryanodine binding sites was reduced by 45% after denervation without modification in affinity. The present findings demonstrate that sarco(endo)plasmic reticulum proteins involved in intracellular calcium homeostasis are clearly down-regulated and brings further evidence of a modified calcium translocation in denervated rat vas deferens.
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Affiliation(s)
- Luis Eduardo M Quintas
- Departamento de Farmacologia Básica e Clínica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Cidade Universitária, 21941-590, Rio de Janeiro, Brazil
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Hrckova G, Velebný S, Halton DW, Day TA, Maule AG. Pharmacological characterisation of neuropeptide F (NPF)-induced effects on the motility of Mesocestoides corti (syn. Mesocestoides vogae) larvae. Int J Parasitol 2004; 34:83-93. [PMID: 14711593 DOI: 10.1016/j.ijpara.2003.10.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neuropeptide F is the most abundant neuropeptide in parasitic flatworms and is analogous to vertebrate neuropeptide Y. This paper examines the effects of neuropeptide F on tetrathyridia of the cestode Mesocestoides vogae and provides preliminary data on the signalling mechanisms employed. Neuropeptide F (>/=10 microM) had profound excitatory effects on larval motility in vitro. The effects were insensitive to high concentrations (1 mM) of the anaesthetic procaine hydrochloride suggesting extraneuronal sites of action. Neuropeptide F activity was not significantly blocked by a FMRFamide-related peptide analog (GNFFRdFamide) that was found to inhibit GNFFRFamide-induced excitation indicating the occurrence of distinct neuropeptide F and FMRFamide-related peptide receptors. Larval treatment with guanosine 5'-O-(2-thiodiphosphate) trilithium salt prior to the addition of neuropeptide F completely abolished the excitatory effects indicating the involvement of G-proteins and a G-protein coupled receptor in neuropeptide F activity. Addition of guanosine 5'-O-(2-thiodiphosphate) following neuropeptide F had limited inhibitory effects consistent with the activation of a signalling cascade by the neuropeptide. With respect to Ca(2+) involvement in neuropeptide F-induced excitation of M. vogae larvae, the L-type Ca(2+)-channel blockers verapamil and nifedipine both abolished neuropeptide F activity as did high Mg(+) concentrations and drugs which blocked sarcoplasmic reticulum Ca(2+)-activated Ca(2+)-channels (ryanodine) and sarcoplasmic reticulum Ca(2+) pumps (cyclopiazonic acid). Therefore, both extracellular and intracellular Ca(2+) is important for neuropeptide F excitation in M. vogae. With respect to second messengers, the protein kinase C inhibitor chelerythrine chloride and the adenylate cyclase inhibitor MDL-2330A both abolished neuropeptide F-induced excitation. The involvement of a signalling pathway that involves protein kinase C was further supported by the fact that phorbol-12-myristate-13-acetate, known to directly activate protein kinase C, had direct excitatory effects on larval motility. Although neuropeptide F is structurally analogous to neuropeptide Y, its mode-of-action in flatworms appears quite distinct from the common signalling mechanism seen in vertebrates.
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Affiliation(s)
- Gabriela Hrckova
- Parasitological Institute of the Slovak Academy of Sciences, Hlinkova 3, 040 01 Kosice, Slovak Republic.
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Scaramello CBV, Cunha VMN, Rodriguez JBR, Noël F. Characterization of subcellular fractions and distribution profiles of transport components involved in Ca(2+) homeostasis in rat vas deferens. J Pharmacol Toxicol Methods 2002; 47:93-8. [PMID: 12459148 DOI: 10.1016/s1056-8719(02)00205-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION The sarcoplasmic reticulum present in eukaryotic cells contains Ca(2+) pumps (SERCA type) that accumulate Ca(2+) from the cytosol and Ca(2+) channels, such as ryanodine receptors and inositol 1,4,5-trisphosphate receptors, that release Ca(2+) from the lumen of this organelle. The use of a preparation rich in sarcoplasmic reticulum vesicles and poorly contaminated with plasmalemmal vesicles would be a prerequisite for studies of Ca(2+) efflux through ryanodine and inositol 1,4,5-trisphosphate receptors, so the present work was aimed to characterize the distribution profiles of various markers of sarcoplasmic reticulum and plasma membrane among fractions obtained from rat vas deferens. METHODS Oxalate-dependent Ca(2+) uptake, thapsigargin-sensitive (Ca(2+)-Mg(2+)) ATPase activity and binding of [3H]ryanodine and [3H]inositol 1,4,5-trisphosphate were measured in the nuclear, mitochondrial, and microsomal fractions obtained by differential centrifugation of rat vas deferens homogenate. RESULTS The recovery of the thapsigargin-resistant (Ca(2+)-Mg(2+)) ATPase activity, supposed to label the plasma membrane, was the same among nuclear, mitochondrial, and microsomal fractions, whereas the recovery of the thapsigargin-sensitive (Ca(2+)-Mg(2+)) activity, oxalate-dependent Ca(2+) uptake, and [3H]inositol 1,4,5-trisphosphate binding, used as sarcoplasmic reticulum markers, was higher in nuclear fraction than in the others. The recovery profiles of the four sarcoplasmic reticulum markers, including [3H]ryanodine binding, were statistically the same among the different subcellular fractions. Caffeine, an agonist of ryanodine receptors, induced the release of 17% of Ca(2+) taken up by the vesicles present in the nuclear fraction but had no effect in microsomes. DISCUSSION Although this nuclear fraction is less purified in sarcoplasmic reticulum markers than the microsomal fraction, it is more suitable for studying Ca(2+) release through ryanodine receptors, primarily because it is less contaminated with vesicles from the plasma membrane which are able to take up Ca(2+) but are insensitive to caffeine.
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Affiliation(s)
- Christianne B V Scaramello
- Departamento de Farmacologia Básica e Clínica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro 21941-590, Brazil
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Noël F, Cunha VM, Silva CL, Mendonça-Silva DL. Control of calcium homeostasis in Schistosoma mansoni. Mem Inst Oswaldo Cruz 2002; 96 Suppl:85-8. [PMID: 11586431 DOI: 10.1590/s0074-02762001000900012] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Calcium signalling is fundamental for muscular contractility of Schistosoma mansoni. We have previously described the presence of transport ATPases (Na+,K+-ATPase and (Ca2+-Mg2+)-ATPase) and calcium channels (ryanodine receptors - RyR) involved in control of calcium homeostasis in this worm. Here we briefly review the main technics (ATPase activity, binding with specific radioligands, fluxes of 45Ca2+ and whole worm contractions) and results obtained in order to compare the distribution patterns of these proteins: thapsigargin-sensitive (Ca2+-Mg2+)-ATPase activity and RyR co-purified in P1 and P4 fractions mainly, which is compatible with a sarcoplasmic reticulum localization, while basal ATPase (along with Na+,K+-ATPase) and thapsigargin-resistant (Ca2+-Mg2+)-ATPase have a distinct distribution, indicative of their plasma membrane localization. Finally we attempt to integrate these contributions with data from other groups in order to propose the first synoptic model for control of calcium homeostasis in S. mansoni.
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Affiliation(s)
- F Noël
- Departamento de Farmacologia Básica e Clínica, ICB, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brasil.
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Da'dara A, Tsai MH, Tao LF, Marx KA, Shoemaker CB, Harn DA, Skelly PJ. Schistosoma mansoni: molecular characterization of a tegumental Ca-ATPase (SMA3). Exp Parasitol 2001; 98:215-22. [PMID: 11560414 DOI: 10.1006/expr.2001.4637] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A cDNA encoding a Ca-ATPase homologue, designated SMA3, was isolated from an adult cDNA library of Schistosoma mansoni. The full-length cloned DNA contains a 3105-bp open reading frame that potentially encodes a 1035-amino-acid protein with a M(r) of 113,729 and a pl of 6.48. Homology searches for SMA3 reveal high sequence identity with a variety of Ca-ATPases from evolutionarily diverse organisms. SMA3 is predicted to contain 10 transmembrane regions typical of this protein family as well as other conserved domains, such as the phosphorylation site and FITC binding domain. The greatest sequence identity (40-50%) is found to those Ca-ATPases belonging to the secretory pathway subclass. Identification of the 5' end of the SMA3 cDNA by RACE analysis reveals the presence of a 36-base spliced leader RNA, suggesting that the SMA3 pre-mRNA is processed by trans-splicing. Northern analysis reveals a single dominant transcript of 5 kb in adult RNA preparations. Antibodies raised against an amino terminal peptide detect the protein in the adult tegument, suggesting that SMA3 functions to help control Ca homeostasis within the tegument and may play a role in signal transduction at the host parasite interface.
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Affiliation(s)
- A Da'dara
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, U.S.A
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Graham MK, McGeown JG, Fairweather I. Ionic mechanisms underlying spontaneous muscle contractions in the liver fluke, Fasciola hepatica. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:R374-83. [PMID: 10444543 DOI: 10.1152/ajpregu.1999.277.2.r374] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Spontaneous contractions of liver fluke muscle were abolished in Ca(2+)-free saline and by 100 microM nifedipine and reduced by 5 mM cadmium chloride, suggesting that they are dependent on extracellular Ca(2+). Caffeine (5 mM) significantly increased contraction amplitude and frequency. Ryanodine (100 microM) failed to block the caffeine response but significantly reduced spontaneous contraction frequency, suggesting that intracellular stores have a functional role. Cyclopiazonic acid (5 microM) had no effect on the caffeine response or spontaneous activity. 3-Isobutyl-1-methylxanthine (IBMX), forskolin, and 8-bromoadenosine 3',5'-cyclic monophosphate significantly increased spontaneous contractions, which implies that cAMP has a regulatory function in motility. Caffeine, however, produced no measurable increase in cAMP. The caffeine effect was inhibited by cadmium chloride and nifedipine, whereas IBMX-induced increases in amplitude were reduced by cadmium chloride. Thus caffeine and cAMP appear capable of opening plasma membrane Ca(2+) channels, but the involvement of cAMP in caffeine responses has not been proved.
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Affiliation(s)
- M K Graham
- School of Biology and Biochemistry, The Queen's University of Belfast, Belfast BT9 7BL, United Kingdom
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Silva CL, Cunha VM, Mendonça-Silva DL, Noël F. Evidence for ryanodine receptors in Schistosoma mansoni. Biochem Pharmacol 1998; 56:997-1003. [PMID: 9776310 DOI: 10.1016/s0006-2952(98)00219-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The present study investigated the presence of ryanodine receptors in the trematode Schistosoma mansoni. [3H]Ryanodine specific binding sites were found in the four subcellular fractions of S. mansoni; however, more binding sites were recovered in the heterogeneous fraction P1 and the microsomal fraction P4, as was thapsigargin-sensitive (Ca2+-Mg2+)ATPase activity, marking the sarco/endoplasmic reticulum calcium ATPase (SERCA) pumps. This binding had an equilibrium dissociation constant (Kd) in the nanomolar range, an apparent maximal number of receptors (Bmax) of about 80 fmol/mg of protein, and was modulated by ions (Ca2+, Mg2+) and some pharmacological tools such as caffeine. Ryanodine was able to accelerate the rate of 45Ca2+ release from actively loaded vesicles, and also to induce a transient contraction of the whole worm. We conclude that ryanodine-sensitive Ca2+ release channels are present in S. mansoni, with properties very similar to the ones present in higher animals.
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Affiliation(s)
- C L Silva
- Departamento de Farmacologia Básica e Clínica, ICB, Universidade Federal do Rio de Janeiro, Cidade Universitária, RJ, Brazil
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Cunha VM, Noël F. Praziquantel has no direct effect on (Na(+)+K+)-ATPases and (Ca2(+)-Mg2+)ATPases of Schistosoma mansoni. Life Sci 1997; 60:PL 289-94. [PMID: 9150424 DOI: 10.1016/s0024-3205(97)00144-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Therapeutic concentrations of praziquantel produce a rapid and intense contraction of the human flatworm Schistosoma mansoni. As an action on ATPases responsible for calcium homeostasis arises as a possible explanation for the molecular mechanism of this effect, we tested here the effect of praziquantel on different preparations from male adult worms that were previously characterized for their content in (Na(+)+K+)-ATPase and (Ca2(+)-Mg2+)ATPase activities from different origins. Concentrations as high as 100 microM praziquantel did not inhibit (Na(+)+K+)-ATPase from tegument and carcass nor (Ca2(+)-Mg2+)ATPase from heterogeneous (P1) and microsomal (P4) fractions. As 100 microM praziquantel was also without effect on calcium permeability of microsomal vesicles actively loaded with 45Ca2+, the present results discard three hypotheses recently raised for the mechanism of praziquantel-induced contraction of S. mansoni.
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Affiliation(s)
- V M Cunha
- Departamento de Farmacologia Básica e Clínica, Instituto de CiênciasBiomédicas, Universidade Federal do Rio de Janeiro, Brazil
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