scholarly journals GAL4 drivers specific for Type Ib and Type Is motor neurons in Drosophila

2018 ◽  
Author(s):  
Juan J. Perez-Moreno ◽  
Cahir J. O’Kane
Keyword(s):  
Neuromuscular Junction ◽  
Motor Neurons ◽  
Cell Biology ◽  
Neuronal Cell ◽  
Model System ◽  
High Expression ◽  
Neuromuscular System ◽  
Type I ◽  
Physiological Properties ◽  
Synaptic Level

ABSTRACTThe Drosophila larval neuromuscular system is extensively used by researchers to study neuronal cell biology, and Drosophila glutamatergic motor neurons (MNs) have become a major model system. There are two main Types of glutamatergic MNs, Ib and Is, with different structural and physiological properties at synaptic level at the neuromuscular junction. To generate genetic tools to identify and manipulate MNs of each Type, we screened for GAL4 driver lines for this purpose. Here we describe GAL4 drivers specific for examples of neurons within each Type, Ib or Is. These drivers showed high expression levels and were expressed in only few MNs, making them amenable tools for specific studies of both axonal and synapse biology in identified Type I MNs.

scholarly journals Neto-α controls synapse organization and homeostasis at the Drosophila neuromuscular junction

2019 ◽  
Author(s):  
Tae Hee Han ◽  
Rosario Vicidomini ◽  
Cathy Isaura Ramos ◽  
Qi Wang ◽  
Peter Nguyen ◽  
...  
Keyword(s):  
Neuromuscular Junction ◽  
Motor Neurons ◽  
Neurotransmitter Release ◽  
Cell Biology ◽  
Expression Patterns ◽  
Dependent Manner ◽  
Independent Function ◽  
Postsynaptic Receptors ◽  
Auxiliary Protein ◽  
And Function

SummaryGlutamate receptor auxiliary proteins control receptor distribution and function, ultimately controlling synapse assembly, maturation and plasticity. At the Drosophila neuromuscular junction (NMJ), a synapse with both pre- and post-synaptic kainate-type glutamate receptors (KARs), we show that the auxiliary protein Neto evolved functionally distinct isoforms to modulate synapse development and homeostasis. Using genetics, cell biology and electrophysiology we demonstrate that Neto-α functions on both sides of the NMJ. In muscle, Neto-α limits the size of the postsynaptic receptors field. In motor neurons, Neto-α controls neurotransmitter release in a KAR-dependent manner. Furthermore, Neto-α is both required and sufficient for the presynaptic increase in neurotransmitter release in response to reduced postsynaptic sensitivity. This KAR-independent function of Neto-α is involved in activity-induced cytomatrix remodeling. We propose that Drosophila ensured NMJ functionality by acquiring two Neto isoforms with differential expression patterns and activities.

scholarly journals Bioengineered model of the human motor unit with physiologically functional neuromuscular junctions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rowan P. Rimington ◽  
Jacob W. Fleming ◽  
Andrew J. Capel ◽  
Patrick C. Wheeler ◽  
Mark P. Lewis
Keyword(s):  
Neuromuscular Junction ◽  
Motor Neuron ◽  
Motor Unit ◽  
Motor Nerve ◽  
Motor Units ◽  
Extracellular Matrices ◽  
Synaptic Membrane ◽  
Type I ◽  
Dependent Manner ◽  
Human Motor

AbstractInvestigations of the human neuromuscular junction (NMJ) have predominately utilised experimental animals, model organisms, or monolayer cell cultures that fail to represent the physiological complexity of the synapse. Consequently, there remains a paucity of data regarding the development of the human NMJ and a lack of systems that enable investigation of the motor unit. This work addresses this need, providing the methodologies to bioengineer 3D models of the human motor unit. Spheroid culture of iPSC derived motor neuron progenitors augmented the transcription of OLIG2, ISLET1 and SMI32 motor neuron mRNAs ~ 400, ~ 150 and ~ 200-fold respectively compared to monolayer equivalents. Axon projections of adhered spheroids exceeded 1000 μm in monolayer, with transcription of SMI32 and VACHT mRNAs further enhanced by addition to 3D extracellular matrices in a type I collagen concentration dependent manner. Bioengineered skeletal muscles produced functional tetanic and twitch profiles, demonstrated increased acetylcholine receptor (AChR) clustering and transcription of MUSK and LRP4 mRNAs, indicating enhanced organisation of the post-synaptic membrane. The number of motor neuron spheroids, or motor pool, required to functionally innervate 3D muscle tissues was then determined, generating functional human NMJs that evidence pre- and post-synaptic membrane and motor nerve axon co-localisation. Spontaneous firing was significantly elevated in 3D motor units, confirmed to be driven by the motor nerve via antagonistic inhibition of the AChR. Functional analysis outlined decreased time to peak twitch and half relaxation times, indicating enhanced physiology of excitation contraction coupling in innervated motor units. Our findings provide the methods to maximise the maturity of both iPSC motor neurons and primary human skeletal muscle, utilising cell type specific extracellular matrices and developmental timelines to bioengineer the human motor unit for the study of neuromuscular junction physiology.

scholarly journals Fibrillar α-synuclein induces neurotoxic astrocyte activation via RIP kinase signaling and NF-κB

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Tsui-Wen Chou ◽  
Nydia P. Chang ◽  
Medha Krishnagiri ◽  
Aisha P. Patel ◽  
Marissa Lindman ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Biology ◽  
Molecular Mechanisms ◽  
Neurodegenerative Disorder ◽  
Neuronal Cell ◽  
Dopamine Neurons ◽  
Functional Markers ◽  
Kinase Signaling ◽  
Astrocyte Activation ◽  
Transcriptional Responses

AbstractParkinson’s disease (PD) is a neurodegenerative disorder characterized by the death of midbrain dopamine neurons. The pathogenesis of PD is poorly understood, though misfolded and/or aggregated forms of the protein α-synuclein have been implicated in several neurodegenerative disease processes, including neuroinflammation and astrocyte activation. Astrocytes in the midbrain play complex roles during PD, initiating both harmful and protective processes that vary over the course of the disease. However, despite their significant regulatory roles during neurodegeneration, the cellular and molecular mechanisms that promote pathogenic astrocyte activity remain mysterious. Here, we show that α-synuclein preformed fibrils (PFFs) induce pathogenic activation of human midbrain astrocytes, marked by inflammatory transcriptional responses, downregulation of phagocytic function, and conferral of neurotoxic activity. These effects required the necroptotic kinases RIPK1 and RIPK3, but were independent of MLKL and necroptosis. Instead, both transcriptional and functional markers of astrocyte activation occurred via RIPK-dependent activation of NF-κB signaling. Our study identifies a previously unknown function for α-synuclein in promoting neurotoxic astrocyte activation, as well as new cell death-independent roles for RIP kinase signaling in the regulation of glial cell biology and neuroinflammation. Together, these findings highlight previously unappreciated molecular mechanisms of pathologic astrocyte activation and neuronal cell death with implications for Parkinsonian neurodegeneration.

Aflatoxin B1 Cytotoxicity in Neurons in Culture

1996 ◽  
Vol 24 (4) ◽  
pp. 533-540 ◽  
Author(s):  
Paola Bonsi ◽  
Maura Palmery ◽  
Gabriella Augusti-Tocco
Keyword(s):  
Motor Neurons ◽  
Aspergillus Parasiticus ◽  
Neuronal Cell ◽  
Cell Number ◽  
Human Brain Tissue ◽  
Proliferating Cells ◽  
Toxin Concentration ◽  
Lower Extent ◽  
Neuronal Cell Lines ◽  
Aflatoxin B

Aflatoxin B1 (AFB1), a metabolite produced by Aspergillus flavus and Aspergillus parasiticus, is mainly known for its strong hepatotoxic and hepatocarcinogenic actions. Acute and reversible effects due to exposure to aflatoxin and the presence of aflatoxins in various human tissues and organs have also been reported. In particular, aflatoxin M1 (a metabolite of AFB1) has been identified in human brain tissue, and a syndrome characterised by encephalopathy has been observed in humans poisoned by AFB1. As a first approach to the study of the neurotoxicity of AFB1, we used the human neuronal cell lines, SKNMC and SKNSH. The data reported show clearly that AFB1 is capable of interacting directly with neuronal cells and causing a decrease in cell number following the addition of toxin to the culture. Decrease in cell survival is dependent on the toxin concentration, on time of exposure, and on cell density. The cytotoxic response of these cells has been compared to the effects of AFB1 on hepatoma cells and spinal cord motor neurons. Postmitotic neurons are also susceptible to AFB1 toxicity, although to a lower extent than proliferating cells. A non-proliferating state thus appears to lower, but not destroy, neuron sensitivity to the toxin.

scholarly journals Expression of cytotactin in the normal and regenerating neuromuscular system.

1989 ◽  
Vol 108 (2) ◽  
pp. 625-635 ◽  
Author(s):  
J K Daniloff ◽  
K L Crossin ◽  
M Pinçon-Raymond ◽  
M Murawsky ◽  
F Rieger ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Neuromuscular Junction ◽  
Schwann Cells ◽  
Node Of Ranvier ◽  
Myotendinous Junction ◽  
Neuromuscular System ◽  
Peripheral Nerve Damage ◽  
Neural Cell Adhesion ◽  
Developing Cerebellum

Cytotactin is an extracellular glycoprotein found in a highly specialized distribution during embryonic development. In the brain, it is synthesized by glia, not neurons. It is involved in neuron-glia adhesion in vitro and affects neuronal migration in the developing cerebellum. In an attempt to extend these observations to the peripheral nervous system, we have examined the distribution and localization of cytotactin in different parts of the normal and regenerating neuromuscular system. In the normal neuromuscular system, cytotactin accumulated at critical sites of cell-cell interactions, specifically at the neuromuscular junction and the myotendinous junction, as well at the node of Ranvier (Rieger, F., J. K. Daniloff, M. Pinçon-Raymond, K. L. Crossin, M. Grumet, and G. M. Edelman. 1986. J. Cell Biol. 103:379-391). At the neuromuscular junction, cytotactin was located in terminal nonmyelinating Schwann cells. Cytotactin was also detected near the insertion points of the muscle fibers to tendinous structures in both the proximal and distal endomysial regions of the myotendinous junctions. This was in striking contrast to staining for the neural cell adhesion molecule, N-CAM, which was accumulated near the extreme ends of the muscle fiber. Peripheral nerve damage resulted in modulation of expression of cytotactin in both nerve and muscle, particularly among the interacting tissues during regeneration and reinnervation. In denervated muscle, cytotactin accumulated in interstitial spaces and near the previous synaptic sites. Cytotactin levels were elevated and remained high along the endoneurial tubes and in the perineurium as long as muscle remained denervated. Reinnervation led to a return to normal levels of cytotactin both in inner surfaces of the nerve fascicles and in the perineurium. In dorsal root ganglia, the processes surrounding ganglionic neurons became intensely stained by anticytotactin antibodies after the nerve was cut, and returned to normal by 30 d after injury. These data suggest that local signals between neurons, glia, and supporting cells may regulate cytotactin expression in the neuromuscular system in a fashion coordinate with other cell adhesion molecules. Moreover, innervation may regulate the relative amount and distribution of cytotactin both in muscle and in Schwann cells.

Cellular studies of peripheral neurons in siphon skin of Aplysia californica

1979 ◽  
Vol 42 (2) ◽  
pp. 530-557 ◽  
Author(s):  
C. H. Bailey ◽  
V. F. Castellucci ◽  
J. Koester ◽  
E. R. Kandel
Keyword(s):  
Motor Neurons ◽  
Synaptic Input ◽  
Firing Pattern ◽  
White Cell ◽  
Type I ◽  
Type Ii ◽  
Peripheral Neurons ◽  
Peripheral Neuron ◽  
Type I Neuron ◽  
Kinetics Of

1. To account for the similarity in the kinetics of habituation between the central and peripheral components of siphon withdrawal, we have tested the idea (52) that each centrally located mechanoreceptor sensory neuron sends two branches to siphon motor neurons; one to centrally located siphon motor neurons and a collateral branch that remains in the periphery and innervates the peripheral siphon motor neurons. 2. We have found a group of peripheral siphon motor neurons and tested the connection onto these cells by central mechanoreceptors. In addition, we have defined by various electrophysiological and morphological criteria two general classes of peripheral neurons that lie along the course of the siphon nerve. 3. One class (type I) consists of only a single cell in each animal. This peripheral neuron typically has the largest cell body found lying along the siphon nerve and is the only peripheral nerve cell that appears white when viewed under epi-illumination. The type I neuron often has a highly regular firing pattern, which occurs in the absence of spontaneous synaptic input. The three-dimensional morphology of this neuron suggests a paucity of fine processes, most of which do not arborize and may terminate in the connective tissue sheath. Fine structural observations of the peripheral white cell have revealed the presence of large densecore granules. The peripheral type I neuron is similar in most of its electrophysiological and morphological properties to central neurons postulated to be neurosecretory. The peripheral white cell is, at present, the only peripheral neuron we can identify with certainty as a unique individual. 4. The second class (type II) of peripheral neurons are siphon motor neurons for the peripheral component of the siphon-withdrawal reflex. In contrast to the type I neurons, members of the second class of peripheral neurons possess smaller, more spherical cell bodies that have varying amounts of orange pigmentation and which give rise to a relatively well-developed and arborized dendritic tree. Type II neurons feature an irregular spontaneous firing pattern that is occasionally modulated by a rich spontaneous synaptic input. Peripheral siphon motor neurons have restricted motor fields that produce contraction of the mantle floor and the base of the siphon. Most of the type II neurons were found to be electrically coupled to one another. 5. The peripheral siphon motor neurons resemble the central siphon motor neurons in that they receive a collateral synapse from centrally located mechanoreceptor sensory neurons. This peripheral sensory-to-motor synapse exhibits the same kinetics of decrement as its central counterpart, both of which parallel behavioral habituation. 6. The rich mechanoreceptor input onto the relatively isolated dendritic trees of the peripheral siphon motor neurons provide a uniquely restricted neuropil to study the sensory-to-motor synapse. The peripheral motor neurons may, therefore, be a useful simple preparation for the cellular study of behavioral plasticity.

scholarly journals Catecholaminergic Fiber Innervation of the Vocal Motor System Is Intrasexually Dimorphic in a Teleost with Alternative Reproductive Tactics

2015 ◽  
Vol 86 (2) ◽  
pp. 131-144 ◽  
Author(s):  
Zachary N. Ghahramani ◽  
Miky Timothy ◽  
Gurpreet Kaur ◽  
Michelle Gorbonosov ◽  
Alena Chernenko ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Motor System ◽  
Advertisement Call ◽  
Motor Nucleus ◽  
Type I ◽  
Type Ii ◽  
Fiber Density ◽  
Reproductive Tactics ◽  
Long Duration ◽  
Behavioral Divergence

Catecholamines, which include the neurotransmitters dopamine and noradrenaline, are known modulators of sensorimotor function, reproduction, and sexually motivated behaviors across vertebrates, including vocal-acoustic communication. Recently, we demonstrated robust catecholaminergic (CA) innervation throughout the vocal motor system in the plainfin midshipman fish Porichthys notatus, a seasonal breeding marine teleost that produces vocal signals for social communication. There are 2 distinct male reproductive morphs in this species: type I males establish nests and court females with a long-duration advertisement call, while type II males sneak spawn to steal fertilizations from type I males. Like females, type II males can only produce brief, agonistic, grunt type vocalizations. Here, we tested the hypothesis that intrasexual differences in the number of CA neurons and their fiber innervation patterns throughout the vocal motor pathway may provide neural substrates underlying divergence in reproductive behavior between morphs. We employed immunofluorescence (-ir) histochemistry to measure tyrosine hydroxylase (TH; a rate-limiting enzyme in catecholamine synthesis) neuron numbers in several forebrain and hindbrain nuclei as well as TH-ir fiber innervation throughout the vocal pathway in type I and type II males collected from nests during the summer reproductive season. After controlling for differences in body size, only one group of CA neurons displayed an unequivocal difference between male morphs: the extraventricular vagal-associated TH-ir neurons, located just lateral to the dimorphic vocal motor nucleus (VMN), were significantly greater in number in type II males. In addition, type II males exhibited greater TH-ir fiber density within the VMN and greater numbers of TH-ir varicosities with putative contacts on vocal motor neurons. This strong inverse relationship between the predominant vocal morphotype and the CA innervation of vocal motor neurons suggests that catecholamines may function to inhibit vocal output in midshipman. These findings support catecholamines as direct modulators of vocal behavior, and differential CA input appears reflective of social and reproductive behavioral divergence between male midshipman morphs.

Tissue inhibitor of metalloproteinases (TIMP) regulates extracellular type I collagen degradation by chondrocytes and endothelial cells

1987 ◽  
Vol 87 (2) ◽  
pp. 357-362
Author(s):  
J. Gavrilovic ◽  
R.M. Hembry ◽  
J.J. Reynolds ◽  
G. Murphy
Keyword(s):  
Endothelial Cells ◽  
Type I Collagen ◽  
Model System ◽  
Collagen Degradation ◽  
Type I ◽  
Tissue Inhibitor Of Metalloproteinases ◽  
Regulatory Factor ◽  
Tissue Inhibitor ◽  
Cells Cultured

A specific antiserum to purified rabbit tissue inhibitor of metalloproteinases (TIMP) was raised in sheep, characterized and used to investigate the role of TIMP in a model system. Chondrocytes and endothelial cells cultured on 14C-labelled type I collagen films and stimulated to produce collagenase were unable to degrade the films unless the anti-TIMP antibody was added. The degradation induced was inhibited by a specific anti-rabbit collagenase antibody. It was concluded that TIMP is a major regulatory factor in cell-mediated collagen degradation.

Sign in / Sign up

Export Citation Format

Share Document