1
|
Romanova EV, Sasaki K, Alexeeva V, Vilim FS, Jing J, Richmond TA, Weiss KR, Sweedler JV. Urotensin II in invertebrates: from structure to function in Aplysia californica. PLoS One 2012; 7:e48764. [PMID: 23144960 PMCID: PMC3493602 DOI: 10.1371/journal.pone.0048764] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Accepted: 10/05/2012] [Indexed: 02/07/2023] Open
Abstract
Neuropeptides are ancient signaling molecules that are involved in many aspects of organism homeostasis and function. Urotensin II (UII), a peptide with a range of hormonal functions, previously has been reported exclusively in vertebrates. Here, we provide the first direct evidence that UII-like peptides are also present in an invertebrate, specifically, the marine mollusk Aplysia californica. The presence of UII in the central nervous system (CNS) of Aplysia implies a more ancient gene lineage than vertebrates. Using representational difference analysis, we identified an mRNA of a protein precursor that encodes a predicted neuropeptide, we named Aplysia urotensin II (apUII), with a sequence and structural similarity to vertebrate UII. With in-situ hybridization and immunohistochemistry, we mapped the expression of apUII mRNA and its prohormone in the CNS and localized apUII-like immunoreactivity to buccal sensory neurons and cerebral A-cluster neurons. Mass spectrometry performed on individual isolated neurons, and tandem mass spectrometry on fractionated peptide extracts, allowed us to define the posttranslational processing of the apUII neuropeptide precursor and confirm the highly conserved cyclic nature of the mature neuropeptide apUII. Electrophysiological analysis of the central effects of a synthetic apUII suggests it plays a role in satiety and/or aversive signaling in feeding behaviors. Finding the homologue of vertebrate UII in the numerically small CNS of an invertebrate animal model is important for gaining insights into the molecular mechanisms and pathways mediating the bioactivity of UII in the higher metazoan.
Collapse
Affiliation(s)
- Elena V. Romanova
- Beckman Institute for Advanced Science and Technology and the Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Kosei Sasaki
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Vera Alexeeva
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Ferdinand S. Vilim
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Jian Jing
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Timothy A. Richmond
- Beckman Institute for Advanced Science and Technology and the Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Klaudiusz R. Weiss
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Jonathan V. Sweedler
- Beckman Institute for Advanced Science and Technology and the Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
| |
Collapse
|
2
|
Distinct mechanisms produce functionally complementary actions of neuropeptides that are structurally related but derived from different precursors. J Neurosci 2010; 30:131-47. [PMID: 20053896 DOI: 10.1523/jneurosci.3282-09.2010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Many bioactive neuropeptides containing RFamide at their C terminus have been described in both invertebrates and vertebrates. To obtain insight into the functional logic of RFamide signaling, we investigate it here in the feeding system of Aplysia. We focus on the expression, localization, and actions of two families of RFamide peptides, the FRFamides and FMRFamide, in the central neuronal circuitry and the peripheral musculature that generate the feeding movements. We describe the cloning of the FRFamide precursor protein and show that the FRFamides and FMRFamide are derived from different precursors. We map the expression of the FRFamide and FMRFamide precursors in the feeding circuitry using in situ hybridization and immunostaining and confirm proteolytic processing of the FRFamide precursor by mass spectrometry. We show that the two precursors are expressed in different populations of sensory neurons in the feeding system. In a representative feeding muscle, we demonstrate the presence of both FRFamides and FMRFamide and their release, probably from the processes of the sensory neurons in the muscle. Both centrally and in the periphery, the FRFamides and FMRFamide act in distinct ways, apparently through distinct mechanisms, and nevertheless, from an overall functional perspective, their actions are complementary. Together, the FRFamides and FMRFamide convert feeding motor programs from ingestive to egestive and depress feeding muscle contractions. We conclude that these structurally related peptides, although derived from different precursors, expressed in different neurons, and acting through different mechanisms, remain related to each other in the functional roles that they play in the system.
Collapse
|
3
|
Jezzini SH, Bodnarova M, Moroz LL. Two-color in situ hybridization in the CNS of Aplysia californica. J Neurosci Methods 2005; 149:15-25. [PMID: 16061289 DOI: 10.1016/j.jneumeth.2005.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Revised: 04/04/2005] [Accepted: 04/08/2005] [Indexed: 10/25/2022]
Abstract
Aplysia californica is an attractive model organism for cellular and systems neuroscience. Currently, there is a growing body of sequence data from Aplysia that includes many interesting genes. To fully exploit this molecular data it must be integrated with the large body of physiological data that are already available for identified neurons in Aplysia networks. In situ hybridization is a powerful technique that enables this to be done. Expression patterns of selected mRNA transcripts can be mapped to individual cells in the central nervous system (CNS). Here, we describe a detailed non-radioactive in situ hybridization protocol optimized for whole-mount preparations of Aplysia ganglia. The indirect alkaline phosphatase-based chromogenic detection method we employ may be used with one or two colors in order to detect one or two different transcripts in the same preparation. The procedure is also compatible with intracellular dye labeling, making it possible to couple localization of transcripts with electrophysiological studies in positively identified neurons. Double labeling was done for transcripts encoding the neuropeptides FMRFamide and sensorin. The sensitive detection of mRNA and great preservation of CNS morphology makes this method a useful tool for analyzing expression patterns of neuron specific genes in Aplysia.
Collapse
Affiliation(s)
- Sami H Jezzini
- The Whitney Laboratory for Marine Bioscience and Department of Neuroscience, University of Florida, 9505 Ocean Shore Blvd., St. Augustine, FL 32080, USA
| | | | | |
Collapse
|
4
|
The enterins: a novel family of neuropeptides isolated from the enteric nervous system and CNS of Aplysia. J Neurosci 2001. [PMID: 11588196 DOI: 10.1523/jneurosci.21-20-08247.2001] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
To identify neuropeptides that have a broad spectrum of actions on the feeding system of Aplysia, we searched for bioactive peptides that are present in both the gut and the CNS. We identified a family of structurally related nonapeptides and decapeptides (enterins) that are present in the gut and CNS of Aplysia, and most of which share the HSFVamide sequence at the C terminus. The structure of the enterin precursor deduced from cDNA cloning predicts 35 copies of 20 different enterins. Northern analysis, in situ hybridization, and immunocytochemistry show that the enterins are abundantly present in the CNS and the gut of Aplysia. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry we characterized the enterin-precursor processing, demonstrated that all of the precursor-predicted enterins are present, and determined post-translational modifications of various enterins. Enterin-positive neuronal somata and processes were found in the gut, and enterins inhibited contractions of the gut. In the CNS, the cerebral and buccal ganglia, which control feeding, contained the enterins. Enterin was also present in the nerve that connects these two ganglia. Enterins reduced the firing of interneurons B4/5 during feeding motor programs. Such enterin-induced reduction of firing also occurred when excitability of B4/5 was tested directly. Because reduction of B4/5 activity corresponds to a switch from egestive to ingestive behaviors, enterin may contribute to such program switching. Furthermore, because enterins are present throughout the nervous system, they may also play a regulatory role in nonfeeding behaviors of Aplysia.
Collapse
|
5
|
Balaban PM, Poteryaev DA, Zakharov IS, Uvarov P, Malyshev A, Belyavsky AV. Up- and down-regulation of Helix command-specific 2 (HCS2) gene expression in the nervous system of terrestrial snail Helix lucorum. Neuroscience 2001; 103:551-9. [PMID: 11246168 DOI: 10.1016/s0306-4522(01)00004-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel gene named Helix command-specific 2 (HCS2) was shown to be expressed predominantly in four giant parietal interneurons involved in withdrawal behavior of the terrestrial snail Helix lucorum L. and several single neurons in other ganglia. Decrease in spontaneous electrophysiological activity of neurons in the isolated CNS by 24h incubation in saline with elevated Mg(2+) concentration significantly decreased the number of HCS2-expressing neurons. Five short-term serotonin applications (each of 10microM), during a 24h incubation of the nervous system in saline induced expression of the HCS2 gene in many cells in cerebral, parietal, pleural and pedal ganglia. Dopamine applications under similar conditions were not effective. Application of anisomycin or cycloheximide, known to block protein synthesis, did not prevent the induction of HCS2 expression under serotonin influence. Skin injury elicited a significant increase in the number of HCS2-expressing cells 24h later in pleural and cerebral ganglia. Incubation of the isolated nervous system preparations for three days in culture medium elicited close to a maximum increase in number of HCS2-expressing cells. Elevation of the normal Mg(2+) concentration in the culture medium significantly decreased the number of cells demonstrating HCS2 expression. Application of the cAMP activator forskolin (10microM) increased the expression under Mg(2+), indicating that cAMP was involved in the up-regulation of HCS2. Application of thapsigargin (10microM), known to release Ca(2+) from intracellular stores, was also effective in increasing expression, suggesting participation of Ca(2+) in regulation of HCS2 expression. Cellular groups expressing the HCS2 gene under different conditions seem to be functionally related since it was demonstrated earlier that some neurons constituting these clusters are involved in the withdrawal behavior and the response of the organism to stress stimuli. From these results we suggest that the HCS2 pattern of expression can be down-regulated by a decrease in synaptic activity in the nervous system, and up-regulated by external noxious inputs, as well as the application of neurotransmitters and second messengers known to be involved in the withdrawal behavior and maintenance of isolated ganglia in culture medium. When up-regulated, the HCS2 expression appears, at least in part in neurons, to be involved in the withdrawal behavior.
Collapse
Affiliation(s)
- P M Balaban
- Institute of Higher Nervous Activity and Neurophysiology, 5A Butlerova Street, 117865, Moscow, Russia.
| | | | | | | | | | | |
Collapse
|
6
|
Bogdanov YD, Balaban PM, Poteryaev DA, Zakharov IS, Belyavsky AV. Putative neuropeptides and an EF-hand motif region are encoded by a novel gene expressed in the four giant interneurons of the terrestrial snail. Neuroscience 1998; 85:637-47. [PMID: 9622259 DOI: 10.1016/s0306-4522(97)00561-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nine giant interneurons located in the pleural and parietal ganglia of the terrestrial snail Helix lucorum L. were reported to be a key element in the network controlling withdrawal behaviour of the animal. Using a combination of complementary DNA subtraction cloning and differential screening approaches we have isolated a novel gene named HCS2 which is expressed predominantly in a subset of these interneurons. The predicted amino acid sequence of the HCS2 protein contains at the N-terminus a hydrophobic leader sequence and four putative neuropeptides, and at the C-terminus a perfect match to the consensus motif of the EF-hand family of the Ca2+-binding proteins. All four predicted neuropeptides bear a C-terminal signature sequence Tyr-Pro-Arg-X (where X is Ile, Leu, Val or Pro), and three of them are likely to be amidated. Physiological action of three synthetic peptides corresponding to the predicted mature HCS2 peptides mimics fairly well the described action of parietal interneurons on follower motoneurons controlling pneumostome closure. In situ hybridization experiments demonstrated that the HCS2 gene is selectively expressed in the four parietal giant interneurons, as well as in several small unidentified neurons. The onset of the HCS2 transcription during embryogenesis coincides temporally with the time-point when the first withdrawal responses of the embryo to tactile stimulation appear. We propose that the HCS2 gene encodes a hybrid precursor protein whose processed products act as neuromodulators or neurotransmitters mediating the withdrawal reactions of the snail, and in addition may participate in the calcium regulatory pathways or calcium homeostasis in command neurons.
Collapse
Affiliation(s)
- Y D Bogdanov
- Engelhardt Institute of Molecular Biology, Moscow, Russia
| | | | | | | | | |
Collapse
|
7
|
Poteryaev DA, Zakharov IS, Balaban PM, Belyavsky AV. A novel neuropeptide precursor gene is expressed in the terrestrial snail central nervous system by a group of neurons that control mating behavior. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1097-4695(199805)35:2<183::aid-neu5>3.0.co;2-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
8
|
Poteryaev DA, Zakharov IS, Balaban PM, Uvarov PN, Belyavsky AV. Characterization of a cDNA clone encoding pedal peptide in the terrestrial snail. Neuroreport 1997; 8:3631-5. [PMID: 9427339 DOI: 10.1097/00001756-199711100-00041] [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: 02/05/2023]
Abstract
We report the isolation of a Helix lucorum cDNA clone encoding a precursor of neuropeptides that are closely related to Aplysia and Tritonia pedal peptides (Pep). The predicted propeptide contains 20 copies of the two variants of Helix Pep interspersed with Lys-Arg endopeptidase cleavage sites. Northern blot hybridization revealed multiple Pep-hybridizing species in the Helix CNS RNA. The Pep gene was expressed by several identified serotonergic neurones in pedal and cerebral ganglia, groups of sensory neurones in procerebrum, peripheral neurones in olfactory bulb, mantle and foot, and group of neurones in pedal ganglia presumably involved in locomotion control. Pep mRNA was detected in several neurones at the early stages of nervous system development.
Collapse
Affiliation(s)
- D A Poteryaev
- Laboratory of Molecular Bases of Differentiation and Development, Engelhardt Institute of Molecular Biology, Moscow, Russia
| | | | | | | | | |
Collapse
|
9
|
Balaban PM, Zakharov IS, Poteryaev DA, Belyavsky AV. Identification of two novel genes specifically expressed in the D-group neurons of the terrestrial snail CNS. INVERTEBRATE NEUROSCIENCE : IN 1996; 2:61-9. [PMID: 9372156 DOI: 10.1007/bf02336661] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A search for genes specifically expressed in the giant interneurons of parietal ganglia of the snail Helix lucorum yielded, among others, two genes named HDS1 and HDS2. According to data obtained by Northern hybridization and whole-mount in situ hybridization, both genes are neurospecific and expressed almost exclusively in the peptidergic D-group neurons (Sakharov, 1974) located in the right parietal ganglion. In situ hybridization of the HDS1 and HDS2 probes with CNS of several related species of the Helicoidea superfamily identified in all cases similarly located homologous groups of neurons. Sequencing of the near full-length cDNA copies of the HDS1 and HDS2 genes revealed open reading frames 107 and 102 amino acids long for HDS1 and HDS2, respectively. Both putative proteins contain a hydrophobic leader peptide and putative recognition sites for furin-like and PC-like endopeptidases. Predicted amino acid sequences of the HDS1 and HDS2 proteins were found to be moderately homologous to each other, as well as to the LYCP preprohormone expressed by the light yellow cells of the freshwater snail Lymnaea stagnalis. These results confirm an earlier hypothesis that the D-group of the Helix family and the light yellow cells of Lymnaea stagnalis represent homologous neuronal groups. Our data suggest that the HDS1 and HDS2 genes encode precursors of secreted molecules, most likely neuropeptides or neurohormones.
Collapse
|