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Mis K, Grubic Z, Lorenzon P, Sciancalepore M, Mars T, Pirkmajer S. In Vitro Innervation as an Experimental Model to Study the Expression and Functions of Acetylcholinesterase and Agrin in Human Skeletal Muscle. Molecules 2017; 22:molecules22091418. [PMID: 28846617 PMCID: PMC6151842 DOI: 10.3390/molecules22091418] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/18/2017] [Accepted: 08/23/2017] [Indexed: 12/19/2022] Open
Abstract
Acetylcholinesterase (AChE) and agrin, a heparan-sulfate proteoglycan, reside in the basal lamina of the neuromuscular junction (NMJ) and play key roles in cholinergic transmission and synaptogenesis. Unlike most NMJ components, AChE and agrin are expressed in skeletal muscle and α-motor neurons. AChE and agrin are also expressed in various other types of cells, where they have important alternative functions that are not related to their classical roles in NMJ. In this review, we first focus on co-cultures of embryonic rat spinal cord explants with human skeletal muscle cells as an experimental model to study functional innervation in vitro. We describe how this heterologous rat-human model, which enables experimentation on highly developed contracting human myotubes, offers unique opportunities for AChE and agrin research. We then highlight innovative approaches that were used to address salient questions regarding expression and alternative functions of AChE and agrin in developing human skeletal muscle. Results obtained in co-cultures are compared with those obtained in other models in the context of general advances in the field of AChE and agrin neurobiology.
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Affiliation(s)
- Katarina Mis
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia.
| | - Zoran Grubic
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia.
| | - Paola Lorenzon
- Department of Life Sciences, University of Trieste, via A. Fleming 22, I-34127 Trieste, Italy.
| | - Marina Sciancalepore
- Department of Life Sciences, University of Trieste, via A. Fleming 22, I-34127 Trieste, Italy.
| | - Tomaz Mars
- Department of Life Sciences, University of Trieste, via A. Fleming 22, I-34127 Trieste, Italy.
| | - Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia.
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Urra J, Blohberger J, Tiszavari M, Mayerhofer A, Lara HE. In vivo blockade of acetylcholinesterase increases intraovarian acetylcholine and enhances follicular development and fertility in the rat. Sci Rep 2016; 6:30129. [PMID: 27440195 PMCID: PMC4954984 DOI: 10.1038/srep30129] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/27/2016] [Indexed: 12/17/2022] Open
Abstract
Growth and differentiation of ovarian follicles are regulated by systemic and local factors, which may include acetylcholine (ACh). Granulosa cells (GCs) of growing follicles and luteal cells produce ACh and in cultured GCs it exerts trophic actions via muscarinic receptors. However, such actions were not studied in vivo. After having established that rat ovarian GCs and luteal cells express the ACh-metabolizing enzyme ACh esterase (AChE), we examined the consequences of local application of an AChE inhibitor, huperzine A (HupA), by osmotic minipump delivery into the ovarian bursa of hemiovariectomized rats. Saline was used in the control group. Local delivery of HupA for 4 weeks increased ovarian ACh content. Estrus cyclicity was not changed indicating a locally restricted range of HupA action. The number of primordial and primary follicles was unaffected, but small secondary follicles significantly increased in the HupA group. Furthermore, a significant increase in the number of corpora lutea suggested increased ovulatory events. In support, as shown upon mating, HupA-treated females had significantly increased implantation sites and more pups. Thus the data are in support of a trophic role of ACh in follicular development and ovulation and point to an important role of ACh in female fertility.
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Affiliation(s)
- Javier Urra
- Laboratory of Neurobiochemistry, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, 8380492 Independencia, Santiago, Chile
| | - Jan Blohberger
- BMC, Cell Biology, Anatomy III, Ludwig-Maximilian-University (LMU), 82152 Planegg, Germany
| | - Michelle Tiszavari
- Laboratory of Neurobiochemistry, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, 8380492 Independencia, Santiago, Chile
| | - Artur Mayerhofer
- BMC, Cell Biology, Anatomy III, Ludwig-Maximilian-University (LMU), 82152 Planegg, Germany
| | - Hernan E Lara
- Laboratory of Neurobiochemistry, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, 8380492 Independencia, Santiago, Chile
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Mis K. Colocalization of acetylcholinesterase, butyrylcholinesterase and choline acetyltransferase in rat spinal cord. Hum Exp Toxicol 2016; 24:543-5. [PMID: 16270756 DOI: 10.1191/0960327105ht560oa] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In our previous in situ hybridization study in the adult rat spinal cord we demonstrated that only neurons express mRNAs for acetylcholinesterase (AChE; EC 3.1.1.7.) and butyrylcholinesterase (BuChE; EC 3.1.1.8.) in this CNS region; no staining was detected for these two messages in the glia cells. Here we used immunocytochemical staining for choline acetyltransferase (ChAT; EC 2.3.1.6.) to answer the, as yet only briefly approached, question whether the cells expressing the messages for both cholinesterases are cholinergic. All neurons expressing mRNAs for AChE and BuChE were found to be ChAT positive. This finding supports the previous proposal that BuChE modulates cholinergic transmission in AChE knockout mice.
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Affiliation(s)
- Katarina Mis
- Laboratory for Molecular Neurobiology, Institute of Pathophysiology, School of Medicine, University of Ljubljana, Slovenia.
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Lindblom RPF, Ström M, Heinig M, Al Nimer F, Aeinehband S, Berg A, Dominguez CA, Vijayaraghavan S, Zhang XM, Harnesk K, Zelano J, Hübner N, Cullheim S, Darreh-Shori T, Diez M, Piehl F. Unbiased expression mapping identifies a link between the complement and cholinergic systems in the rat central nervous system. THE JOURNAL OF IMMUNOLOGY 2013; 192:1138-53. [PMID: 24353269 DOI: 10.4049/jimmunol.1301233] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The complement system is activated in a wide spectrum of CNS diseases and is suggested to play a role in degenerative phenomena such as elimination of synaptic terminals. Still, little is known of mechanisms regulating complement activation in the CNS. Loss of synaptic terminals in the spinal cord after an experimental nerve injury is increased in the inbred DA strain compared with the PVG strain and is associated with expression of the upstream complement components C1q and C3, in the absence of membrane attack complex activation and neutrophil infiltration. To further dissect pathways regulating complement expression, we performed genome-wide expression profiling and linkage analysis in a large F2(DA × PVG) intercross, which identified quantitative trait loci regulating expression of C1qa, C1qb, C3, and C9. Unlike C1qa, C1qb, and C9, which all displayed distinct coregulation with different cis-regulated C-type lectins, C3 was regulated in a coexpression network immediately downstream of butyrylcholinesterase. Butyrylcholinesterase hydrolyses acetylcholine, which exerts immunoregulatory effects partly through TNF-α pathways. Accordingly, increased C3, but not C1q, expression was demonstrated in rat and mouse glia following TNF-α stimulation, which was abrogated in a dose-dependent manner by acetylcholine. These findings demonstrate new pathways regulating CNS complement expression using unbiased mapping in an experimental in vivo system. A direct link between cholinergic activity and complement activation is supported by in vitro experiments. The identification of distinct pathways subjected to regulation by naturally occurring genetic variability is of relevance for the understanding of disease mechanisms in neurologic conditions characterized by neuronal injury and complement activation.
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Affiliation(s)
- Rickard P F Lindblom
- Neuroimmunology Unit, Department of Clinical Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden
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Mis K, Matkovic U, Pirkmajer S, Sciancalepore M, Lorenzon P, Mars T, Grubic Z. Acetylcholinesterase and agrin: different functions, similar expression patterns, multiple roles. Chem Biol Interact 2012; 203:297-301. [PMID: 23117006 DOI: 10.1016/j.cbi.2012.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/16/2012] [Accepted: 10/17/2012] [Indexed: 12/31/2022]
Abstract
Acetylcholinesterase (AChE) and agrin play unique functional roles in the neuromuscular junction (NMJ). AChE is a cholinergic and agrin a synaptogenetic component. In spite of their different functions, they share several common features: their targeting is determined by alternative splicing; unlike most other NMJ components they are expressed in both, muscle and motor neuron and both reside on the synaptic basal lamina of the NMJ. Also, both were reported to play various nonjunctional roles. However, while the origin of basal lamina bound agrin is undoubtedly neural, the neural origin of AChE, which is anchored to the basal lamina with collagenic tail ColQ, is elusive. Hypothesizing that motor neuron proteins targeted to the NMJ basal lamina share common temporal pattern of expression, which is coordinated with the formation of basal lamina, we compared expression of agrin isoforms with the expression of AChE-T and ColQ in the developing rat spinal cord at the stages before and after the formation of NMJ basal lamina. Cellular origin of AChE-T and agrin was determined by in situ hybridization and their quantitative levels by RT PCR. We found parallel increase in expression of the synaptogenetic (agrin 8) isoform of agrin and ColQ after the formation of basal lamina supporting the view that ColQ bound AChE and agrin 8 isoform are destined to the basal lamina. Catalytic AChE-T subunit and agrin isoforms 19 and 0 followed different expression patterns. In accordance with the reports of other authors, our investigations also revealed various alternative functions for AChE and agrin. We have already demonstrated participation of AChE in myoblast apoptosis; here we present the evidence that agrin promotes the maturation of heavy myosin chains and the excitation-contraction coupling. These results show that common features of AChE and agrin extend to their capacity to play multiple roles in muscle development.
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Affiliation(s)
- Katarina Mis
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Mis K, Mars T, Golicnik M, Jevsek M, Grubic Z. Effects of acetylcholinesterase gene silencing on its activity in cultured human skeletal muscle. J Mol Neurosci 2007; 30:31-2. [PMID: 17192616 DOI: 10.1385/jmn:30:1:31] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
In spite of several reports demonstrating that acetylcholinesterase (AChE [EC 3.1.1.7]) expression is importantly regulated at the level of its mRNA, we still know little about the relationship between AChE mRNA level and the level of mature, catalytically active enzyme in the cell. Better insight into this relationship is, however, essential for our understanding of the molecular pathways underlying AChE synthesis in living cells. We have approached this problem previously (Grubic et al., 1995; Brank et al., 1998; Mis et al., 2003; Jevsek et al., 2004); however, recently introduced small interfering RNA (siRNA) methodology, which allows blockade of gene expression at the mRNA level, opens new possibilities in approaching the AChE mRNA-AChE activity relationship. With this technique one can eliminate AChE mRNA in the cell, specifically and at selected times, and follow the effects of such treatment at the mature enzyme level. In this study we followed AChE activity in siRNA-treated cultured human myoblasts. Our aim was to find out how the temporal profile of the AChE mRNA decrease is reflected at the level of AChE activity under normal conditions and after inhibition of preexisting AChE by diisopropyl phosphorofluoridate (DFP).AChE activity was determined at selected time intervals after siRNA treatment in both myoblast homogenates and in culture medium to follow the effects of siRNA treatment at the level of intracellular AChE synthesis and at the level of AChE secreted from the cell.
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Affiliation(s)
- Katarina Mis
- Institute of Pathophysiology, University of Ljubljana, Slovenia SI-1000
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Mis K, Mars T, Jevsek M, Strasek H, Golicnik M, Brecelj J, Komel R, King MP, Miranda AF, Grubic Z. Expression and distribution of acetylcholinesterase among the cellular components of the neuromuscular junction formed in human myotube in vitro. Chem Biol Interact 2005; 157-158:29-35. [PMID: 16256091 DOI: 10.1016/j.cbi.2005.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The results of our recent investigations on the expression and distribution of acetylcholinesterase (EC. 3.1.1.7, AChE) in the experimental model of the in vitro innervated human muscle are summarized and discussed here. This is the only model allowing studies on AChE expression at all stages of the neuromuscular junction (NMJ) formation in the human muscle. Since it consists not only of the motor neurons and myotubes but also of glial cells, which are essential for the normal development of the motor neurons, NMJs become functional and differentiated in this system. We followed AChE expression at various stages of the NMJ formation and in the context of other events characteristic for this process. Neuronal and muscular part were analysed at both, mRNA and mature enzyme level. AChE is expressed in motor neurons and skeletal muscle at the earliest stages of their development, long before NMJ starts to form and AChE begins to act as a cholinergic component. Temporal pattern of AChE mRNA expression in motor neurons is similar to the pattern of mRNA encoding synaptogenetic variant of agrin. There are no AChE accummulations at the NMJ at the early stage of its formation, when immature clusters of nicotinic receptors are formed at the neuromuscular contacts and when occasional NMJ-mediated contractions are already observed. The transformation from immature, bouton-like neuromuscular contacts into differentiated NMJs with mature, compact receptor clusters, myonuclear accumulations and dense AChE patches begins at the time when basal lamina starts to form in the synaptic cleft. Our observations support the concept that basal lamina formation is the essential event in the transformation of immature neuromuscular contact into differentiated NMJ, with the accumulation of not only muscular but also neuronal AChE in the synaptic cleft.
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Affiliation(s)
- Katarina Mis
- Laboratory for Molecular Neurobiology, Institute of Pathophysiology, Medical Faculty, School of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia
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Jevsek M, Mars T, Mis K, Grubic Z. Origin of acetylcholinesterase in the neuromuscular junction formed in the in vitro innervated human muscle. Eur J Neurosci 2004; 20:2865-71. [PMID: 15579140 DOI: 10.1111/j.1460-9568.2004.03752.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synaptic basal lamina is interposed between the pre- and postsynaptic membrane of the neuromuscular junction (NMJ). This position permits deposition of basal lamina-bound NMJ components of both neuronal and muscle fibre origin. One such molecule is acetylcholinesterase (AChE). The origin of NMJ AChE has been investigated previously as the answer would elucidate the relative contributions of muscle fibers and motor neurons to NMJ formation. However, in the experimental models used in prior investigations either the neuronal or muscular components of the NMJs were removed, or the NMJs were poorly differentiated. Therefore, the question of AChE origin in the intact and functional NMJ remains open. Here, we have approached this question using an in vitro model in which motor neurons, growing from embryonic rat spinal cord explants, form well differentiated NMJs with cultured human myotubes. By immunocytochemical staining with species-specific anti-AChE antibodies, we are able to differentiate between human (muscular) and rat (neuronal) AChE at the NMJ. We observed strong signal at the NMJ after staining with human AChE antibodies, which suggests a significant muscular AChE contribution. However, a weaker, but still clearly recognizable signal is observed after staining with rat AChE antibodies, suggesting a smaller fraction of AChE was derived from motor neurons. This is the first report demonstrating that both motor neuron and myotube contribute synaptic AChE under conditions where they interact with each other in the formation of an intact and functional NMJ.
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Affiliation(s)
- Marko Jevsek
- Laboratory for Molecular Neurobiology, Institute of Pathophysiology, Medical School, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia
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