Evidence for the presence of glutamatergic receptors in adult Schistosoma mansoni

Mendonça-Silva, Dayde Lane; Pessôa, Renata Fittipaldi; Noël, François

doi:10.1016/s0006-2952(02)01358-8

Cited by 26 publications

(20 citation statements)

References 31 publications

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“…Other GPCRs such as SmGPR-3 [39] and SmD2 [40] which are activated by dopamine and are expressed in the central/peripheral nervous systems and body wall musculature, respectively, might influence S. mansoni movement in a complex fashion given that dopamine suppresses S. mansoni motor activity [39], [41] but induces cAMP production via SmD2 [40]. Furthermore, l -glutamate induces muscle contraction in isolated S. mansoni muscle fibres [42] likely via l -glutamate receptors [43] and kainic acid, an agonist that mimics the effect of glutamate, causes hyperkinesias and coiling in adult worms [44] similar to that observed with forskolin in the present study. Motor activity in S. mansoni thus appears to be under complex regulatory control from neuromodulators and classical neurotransmitters some of which will likely signal to PKA.…”

Section: Discussionmentioning

confidence: 99%

Functional Mapping of Protein Kinase A Reveals Its Importance in Adult Schistosoma mansoni Motor Activity

et al. 2013

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Cyclic AMP (cAMP)-dependent protein kinase/protein kinase A (PKA) is the major transducer of cAMP signalling in eukaryotic cells. Here, using laser scanning confocal microscopy and ‘smart’ anti-phospho PKA antibodies that exclusively detect activated PKA, we provide a detailed in situ analysis of PKA signalling in intact adult Schistosoma mansoni, a causative agent of debilitating human intestinal schistosomiasis. In both adult male and female worms, activated PKA was consistently found associated with the tegument, oral and ventral suckers, oesophagus and somatic musculature. In addition, the seminal vesicle and gynaecophoric canal muscles of the male displayed activated PKA whereas in female worms activated PKA localized to the ootype wall, the ovary, and the uterus particularly around eggs during expulsion. Exposure of live worms to the PKA activator forskolin (50 µM) resulted in striking PKA activation in the central and peripheral nervous system including at nerve endings at/near the tegument surface. Such neuronal PKA activation was also observed without forskolin treatment, but only in a single batch of worms. In addition, PKA activation within the central and peripheral nervous systems visibly increased within 15 min of worm-pair separation when compared to that observed in closely coupled worm pairs. Finally, exposure of adult worms to forskolin induced hyperkinesias in a time and dose dependent manner with 100 µM forskolin significantly increasing the frequency of gross worm movements to 5.3 times that of control worms (P≤0.001). Collectively these data are consistent with PKA playing a central part in motor activity and neuronal communication, and possibly interplay between these two systems in S. mansoni. This study, the first to localize a protein kinase when exclusively in an activated state in adult S. mansoni, provides valuable insight into the intricacies of functional protein kinase signalling in the context of whole schistosome physiology.

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Section: Discussionmentioning

confidence: 99%

Functional Mapping of Protein Kinase A Reveals Its Importance in Adult Schistosoma mansoni Motor Activity

et al. 2013

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“…Previously, glutamate was detected in the nervous system of S. mansoni [9] and glutamate agonists were reported to have an effect on motor activity [12]. Thus we had expected to find SmGBP in the CNS or the peripheral innervation of the musculature but, surprisingly, no expression was detected in these sites.…”

Section: Discussionmentioning

confidence: 85%

“…For example, glutamate was shown to stimulate muscle contraction when applied onto isolated muscle fibers of S. mansoni [10] and muscle strips of the tapeworm, Hymenolepis diminuta [11]. Moreover, treatment of cultured schistosomes with glutamate agonists produced strong body wall contractions and hyperkinesis [12], suggesting a probable role in the coordination of the somatic muscles and movement. The mechanisms responsible for these effects are largely unknown.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a Truncated Metabotropic Glutamate Receptor in a Primitive Metazoan, the Parasitic Flatworm Schistosoma mansoni

Taman

Ribeiro

2011

PLoS ONE

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A novel glutamate-binding protein was identified in Schistosoma mansoni. The protein (SmGBP) is related to metabotropic glutamate receptors from other species and has a predicted glutamate binding site located within a Venus Flytrap module but it lacks the heptahelical transmembrane segment that normally characterizes these receptors. The SmGBP cDNA was cloned, verified by 5′ and 3′ Rapid Amplification of cDNA Ends (RACE) and shown to be polyadenylated at the 3′end, suggesting the transcript is full-length. The cloned cDNA was subsequently expressed in bacteria and shown to encode a functional glutamate-binding protein. Other studies, using a specific peptide antibody, determined that SmGBP exists in two forms, a monomer of the expected size and a stable but non-covalent dimer. The monomer and dimer are both present in the membrane fraction of S. mansoni and are resistant to extraction with high-salt, alkaline pH and urea, suggesting SmGBP is either an integral membrane protein or a peripheral protein that is tightly associated with the membrane. Surface biotinylation experiments combined with western blot analyses and confocal immunolocalization revealed that SmGBP localized to the surface membranes of adult male schistosomes, especially the dorsal tubercles. In contrast, we detected little or no expression of SmGBP either in the females or larval stages. A comparative quantitative PCR analysis confirmed that the level of SmGBP expression is several-fold higher in male worms than cercariae, and it is barely detectable in adult females. Together, the results identify SmGBP as a new type of schistosome glutamate receptor that is both gender- and stage-specific. The high-level expression of this protein in the male tubercles suggests a possible role in host-parasite interaction.

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“…In fact, pharmacological and immunohistochemical evidence has strong suggested that L-glutamate and L-aspartate are neurotransmitters in platyhelminths (Keenan and Koopowitz, 1982;Mendonça-Silva et al, 2002;Miller et al, 1996;Webb, 1987). The precise identity of EgAT1 inside the DAACS family could not be defined by bioinformatic analysis.…”

Section: Discussionmentioning

confidence: 99%

Sequencing, bioinformatic characterization and expression pattern of a putative amino acid transporter from the parasitic cestode Echinococcus granulosus

Camicia¹,

Paredes²,

Chalar

et al. 2008

Gene

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Evidence for the presence of glutamatergic receptors in adult Schistosoma mansoni

Cited by 26 publications

References 31 publications

Functional Mapping of Protein Kinase A Reveals Its Importance in Adult Schistosoma mansoni Motor Activity

Functional Mapping of Protein Kinase A Reveals Its Importance in Adult Schistosoma mansoni Motor Activity

Characterization of a Truncated Metabotropic Glutamate Receptor in a Primitive Metazoan, the Parasitic Flatworm Schistosoma mansoni

Sequencing, bioinformatic characterization and expression pattern of a putative amino acid transporter from the parasitic cestode Echinococcus granulosus

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