scholarly journals Astroglial dysfunctions drive aberrant synaptogenesis in developing brain with lengthy general anesthesia

2018 ◽  
Author(s):  
Bin Zhou ◽  
Lingmin Chen ◽  
Ping Liao ◽  
Lu Huang ◽  
Zhuo Chen ◽  
...  
Keyword(s):  
Cognitive Deficits ◽  
Synaptic Function ◽  
Developing Brain ◽  
Actin Binding ◽  
General Anesthetics ◽  
Cellular Mechanisms ◽  
Genetic Intervention ◽  
Synaptic Structure ◽  
And Function

AbstractLengthy use of general anesthetics (GAs) causes cognitive deficits in developing brain, which has raised significant clinical concerns such that FDA is warning on the use of GAs in children younger than 3 years. However, the molecular and cellular mechanisms for GAs-induced neurotoxicity remain largely unknown. Here we report that sevoflurane, a commonly used GA in pediatrics, causes compromised astrocyte morphogenesis, spatiotemporally correlated to the synaptic overgrowth with reduced synaptic function in developing cortex in a regional-, exposure-length- and age-specific manner. Sevoflurane disrupts astrocyte Ca2+ homeostasis both acutely and chronically, which leads to the down regulation of Ezrin, an actin-binding membrane protein, which we found is critically involved in astrocyte morphogenesis in vivo. Importantly, in normal developing brain, the genetic intervention of astrocyte morphogenesis is sufficient to produce the aberrant synaptic structure and function virtually identical to the ones induced by lengthy sevoflurane exposure. Our data uncover that astrocytes are unexpectedly central targets for GAs to exert toxic effects, and that astrocyte morphological integrity is crucial for synaptogenesis in the developing brain.

scholarly journals Direct regulation of Arp2/3 complex activity and function by the actin binding protein coronin

2002 ◽  
Vol 159 (6) ◽  
pp. 993-1004 ◽  
Author(s):  
Christine L. Humphries ◽  
Heath I. Balcer ◽  
Jessica L. D'Agostino ◽  
Barbara Winsor ◽  
David G. Drubin ◽  
...  
Keyword(s):  
Binding Protein ◽  
Coiled Coil ◽  
Actin Binding ◽  
Complex Activity ◽  
Actin Binding Protein ◽  
Coiled Coil Domain ◽  
Allele Specific ◽  
And Function

Mechanisms for activating the actin-related protein 2/3 (Arp2/3) complex have been the focus of many recent studies. Here, we identify a novel mode of Arp2/3 complex regulation mediated by the highly conserved actin binding protein coronin. Yeast coronin (Crn1) physically associates with the Arp2/3 complex and inhibits WA- and Abp1-activated actin nucleation in vitro. The inhibition occurs specifically in the absence of preformed actin filaments, suggesting that Crn1 may restrict Arp2/3 complex activity to the sides of filaments. The inhibitory activity of Crn1 resides in its coiled coil domain. Localization of Crn1 to actin patches in vivo and association of Crn1 with the Arp2/3 complex also require its coiled coil domain. Genetic studies provide in vivo evidence for these interactions and activities. Overexpression of CRN1 causes growth arrest and redistribution of Arp2 and Crn1p into aberrant actin loops. These defects are suppressed by deletion of the Crn1 coiled coil domain and by arc35-26, an allele of the p35 subunit of the Arp2/3 complex. Further in vivo evidence that coronin regulates the Arp2/3 complex comes from the observation that crn1 and arp2 mutants display an allele-specific synthetic interaction. This work identifies a new form of regulation of the Arp2/3 complex and an important cellular function for coronin.

scholarly journals Application of Echocardiography on Transgenic Mice with Cardiomyopathies

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
G. Chen ◽  
Y. Li ◽  
J. Tian ◽  
L. Zhang ◽  
P. Jean-Charles ◽  
...  
Keyword(s):  
Heart Failure ◽  
Transgenic Mice ◽  
Tissue Doppler ◽  
Doppler Imaging ◽  
Cellular Mechanisms ◽  
Embryonic Mouse ◽  
Experimental Animals ◽  
Therapeutic Outcomes ◽  
And Function

Cardiomyopathies are common cardiac disorders that primarily affect cardiac muscle resulting in cardiac dysfunction and heart failure. Transgenic mouse disease models have been developed to investigate the cellular mechanisms underlying heart failure and sudden cardiac death observed in cardiomyopathy cases and to explore the therapeutic outcomes in experimental animals in vivo. Echocardiography is an essential diagnostic tool for accurate and noninvasive assessment of cardiac structure and function in experimental animals. Our laboratory has been among the first to apply high-frequency research echocardiography on transgenic mice with cardiomyopathies. In this work, we have summarized our and other studies on assessment of systolic and diastolic dysfunction using conventional echocardiography, pulsed Doppler, and tissue Doppler imaging in transgenic mice with various cardiomyopathies. Estimation of embryonic mouse hearts has been performed as well using this high-resolution echocardiography. Some technical considerations in mouse echocardiography have also been discussed.

scholarly journals CSPα reduces aggregates and rescues striatal dopamine release in αsynuclein transgenic mice

2020 ◽  
Author(s):  
L Caló ◽  
E Hidari ◽  
M Wegrzynowicz ◽  
JW Dalley ◽  
BL Schneider ◽  
...  
Keyword(s):  
Dopamine Release ◽  
Early Stage ◽  
Synaptic Function ◽  
Snare Complex ◽  
Early Event ◽  
Vesicle Recycling ◽  
Cysteine String Protein ◽  
And Function

AbstractαSynuclein aggregation at the synapse is an early event in Parkinson’s disease and is associated with impaired striatal synaptic function and dopaminergic neuronal death. The cysteine string protein (CSPα) and αsynuclein have partially overlapping roles in maintaining synaptic function and mutations in each cause neurodegenerative diseases. CSPα is a member of the DNAJ/HSP40 family of co-chaperones and like αsynuclein, chaperones the SNARE complex assembly and neurotransmitter release. αSynuclein can rescue neurodegeneration in CSPαKO mice. However, whether αsynuclein aggregation alters CSPα expression and function is unknown. Here we show that αsynuclein aggregation at the synapse induces a decrease in synaptic CSPα and a reduction in the complexes that CSPα forms with HSC70 and STGa. We further show that viral delivery of CSPα rescues in vitro the impaired vesicle recycling in PC12 cells with αsynuclein aggregates and in vivo reduces synaptic αsynuclein aggregates restoring normal dopamine release in 1-120hαsyn mice. These novel findings reveal a mechanism by which αsynuclein aggregation alters CSPα at the synapse, and show that CSPα rescues αsynuclein aggregation-related phenotype in 1-120hαsyn mice similar to the effect of αsynuclein in CSPαKO mice. These results implicate CSPα as a potential therapeutic target for the treatment of early-stage PD.

scholarly journals Molecular mechanisms of olfactory detection in insects: beyond receptors

Open Biology ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 200252
Author(s):  
Hayden R. Schmidt ◽  
Richard Benton
Keyword(s):  
Molecular Mechanisms ◽  
Olfactory Receptors ◽  
Environmental Chemicals ◽  
Ecological Niches ◽  
Cellular Mechanisms ◽  
Signalling Molecules ◽  
Olfactory Systems ◽  
Lymph Fluid ◽  
And Function

Insects thrive in diverse ecological niches in large part because of their highly sophisticated olfactory systems. Over the last two decades, a major focus in the study of insect olfaction has been on the role of olfactory receptors in mediating neuronal responses to environmental chemicals. In vivo , these receptors operate in specialized structures, called sensilla, which comprise neurons and non-neuronal support cells, extracellular lymph fluid and a precisely shaped cuticle. While sensilla are inherent to odour sensing in insects, we are only just beginning to understand their construction and function. Here, we review recent work that illuminates how odour-evoked neuronal activity is impacted by sensillar morphology, lymph fluid biochemistry, accessory signalling molecules in neurons and the physiological crosstalk between sensillar cells. These advances reveal multi-layered molecular and cellular mechanisms that determine the selectivity, sensitivity and dynamic modulation of odour-evoked responses in insects.

Synaptopathy: dysfunction of synaptic function?

2010 ◽  
Vol 38 (2) ◽  
pp. 443-444 ◽  
Author(s):  
Nils Brose ◽  
Vincent O'Connor ◽  
Paul Skehel
Keyword(s):  
Animal Experimentation ◽  
Structure And Function ◽  
Synaptic Function ◽  
Cellular Systems ◽  
Brain Diseases ◽  
Psychiatric Disease ◽  
Synaptic Dysfunction ◽  
A Value ◽  
Synaptic Structure ◽  
And Function

Synaptopathy is an increasingly popular term used to define key features of neurodegenerative and psychiatric disease. It implies that disruptions in synaptic structure and function are potentially the major determinant of such brain diseases. The Synaptopathies: Dysfunction of Synaptic Function Biochemical Society Focused Meeting brought together several invited speakers, supplemented with short communications from young scientists, who addressed this possibility. The talks spanned the full gamut of approaches that brought molecular, cellular, systems and whole-animal experimentation together to address how fundamental synaptic biology was increasingly informing on dysfunction in disease. The disease and models thereof discussed included Alzheimer's disease, prions, Huntington's disease, Parkinson's disease, schizophrenia and autism. The audience were asked to reflect on whether synaptopathy, although attractive and conceptually useful, provided a significant explanation as the cause of these major diseases. The breadth of the meeting reinforced the complexity of these brain diseases, supported the significance of synaptic dysfunction in disease, but left open the issue as to whether the prime cause of these disorders could be resolved as simple synaptic dysfunction. Thus, despite revealing a value of synaptopathy, further investigation will be required to reveal its balance in the cause and effect in each of the major brain diseases.

scholarly journals Dynamic Localization and Function of Bni1p at the Sites of Directed Growth in Saccharomyces cerevisiae

2001 ◽  
Vol 21 (3) ◽  
pp. 827-839 ◽  
Author(s):  
Kumi Ozaki-Kuroda ◽  
Yasunori Yamamoto ◽  
Hidenori Nohara ◽  
Makoto Kinoshita ◽  
Takeshi Fujiwara ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fluorescent Protein ◽  
Imaging System ◽  
Cell Polarization ◽  
Actin Binding ◽  
Cortical Actin ◽  
Dynamic Localization ◽  
Directed Growth ◽  
And Function

ABSTRACT Formin homology (FH) proteins are implicated in cell polarization and cytokinesis through actin organization. There are two FH proteins in the yeast Saccharomyces cerevisiae, Bni1p and Bnr1p. Bni1p physically interacts with Rho family small G proteins (Rho1p and Cdc42p), actin, two actin-binding proteins (profilin and Bud6p), and a polarity protein (Spa2p). Here we analyzed the in vivo localization of Bni1p by using a time-lapse imaging system and investigated the regulatory mechanisms of Bni1p localization and function in relation to these interacting proteins. Bni1p fused with green fluorescent protein localized to the sites of cell growth throughout the cell cycle. In a small-budded cell, Bni1p moved along the bud cortex. This dynamic localization of Bni1p coincided with the apparent site of bud growth. Abni1-disrupted cell showed a defect in directed growth to the pre-bud site and to the bud tip (apical growth), causing its abnormally spherical cell shape and thick bud neck. Bni1p localization at the bud tips was absolutely dependent on Cdc42p, largely dependent on Spa2p and actin filaments, and partly dependent on Bud6p, but scarcely dependent on polarized cortical actin patches or Rho1p. These results indicate that Bni1p regulates polarized growth within the bud through its unique and dynamic pattern of localization, dependent on multiple factors, including Cdc42p, Spa2p, Bud6p, and the actin cytoskeleton.

scholarly journals Neurexin–Neuroligin 1 regulates synaptic morphology and functions via the WAVE regulatory complex in Drosophila neuromuscular junction

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Guanglin Xing ◽  
Moyi Li ◽  
Yichen Sun ◽  
Menglong Rui ◽  
Yan Zhuang ◽  
...  
Keyword(s):  
Neuromuscular Junction ◽  
Molecular Mechanisms ◽  
Postsynaptic Membrane ◽  
Synaptic Function ◽  
Actin Assembly ◽  
Actin Reorganization ◽  
Synaptic Structure ◽  
Structural And Functional Properties ◽  
Regulatory Complex ◽  
And Function

Neuroligins are postsynaptic adhesion molecules that are essential for postsynaptic specialization and synaptic function. But the underlying molecular mechanisms of neuroligin functions remain unclear. We found that Drosophila Neuroligin 1 (DNlg1) regulates synaptic structure and function through WAVE regulatory complex (WRC)-mediated postsynaptic actin reorganization. The disruption of DNlg1, DNlg2, or their presynaptic partner neurexin (DNrx) led to a dramatic decrease in the amount of F-actin. Further study showed that DNlg1, but not DNlg2 or DNlg3, directly interacts with the WRC via its C-terminal interacting receptor sequence. That interaction is required to recruit WRC to the postsynaptic membrane to promote F-actin assembly. Furthermore, the interaction between DNlg1 and the WRC is essential for DNlg1 to rescue the morphological and electrophysiological defects in dnlg1 mutants. Our results reveal a novel mechanism by which the DNrx-DNlg1 trans-synaptic interaction coordinates structural and functional properties at the neuromuscular junction.

scholarly journals Microvilli-derived Extracellular Vesicles Govern Morphogenesis in Drosophila wing epithelium

2020 ◽  
Author(s):  
Ilse Hurbain ◽  
Anne-Sophie Macé ◽  
Maryse Romao ◽  
Lucie Sengmanivong ◽  
Laurent Ruel ◽  
...  
Keyword(s):  
Long Range ◽  
Extracellular Vesicles ◽  
Cell Biology ◽  
Extracellular Vesicle ◽  
Wing Disc ◽  
Cellular Mechanisms ◽  
Long Distance ◽  
Drosophila Wing ◽  
And Function

ABSTRACTThe regulation and coordination of developmental processes involves the secretion of morphogens and membrane carriers, including extracellular vesicles, which facilitate their transport over long distance. The long-range activity of the Hedgehog morphogen is conveyed by extracellular vesicles. However, the site and the molecular basis of their biogenesis remains unknown. By combining fluorescence and electron microscopy combined with genetics and cell biology approaches, we investigated the origin and the cellular mechanisms underlying extracellular vesicle biogenesis, and their contribution to Drosophila wing disc development, exploiting Hedgehog as a long-range morphogen. We show that microvilli of Drosophila wing disc epithelium are the site of generation of small extracellular vesicles that transport Hedgehog across the tissue. This process requires the Prominin-like protein, whose activity, together with interacting cytoskeleton components and lipids, is critical for maintaining microvilli integrity and function in secretion. Our results provide the first evidence that microvilli-derived extracellular vesicles contribute to Hedgehog long-range signaling activity highlighting their physiological significance in tissue development in vivo.

scholarly journals Drosophila MIC60/mitofilin conducts dual roles in mitochondrial motility and crista structure

2017 ◽  
Vol 28 (24) ◽  
pp. 3471-3479 ◽  
Author(s):  
Pei-I Tsai ◽  
Amanda M. Papakyrikos ◽  
Chung-Han Hsieh ◽  
Xinnan Wang
Keyword(s):  
Neuromuscular Junctions ◽  
Cellular Level ◽  
Dual Roles ◽  
Protein Levels ◽  
Mitochondrial Homeostasis ◽  
Synaptic Structure ◽  
Microtubule Motors ◽  
Mitochondrial Motility ◽  
And Function

MIC60/mitofilin constitutes a hetero-oligomeric complex on the inner mitochondrial membranes to maintain crista structure. However, little is known about its physiological functions. Here, by characterizing Drosophila MIC60 mutants, we define its roles in vivo. We discover that MIC60 performs dual functions to maintain mitochondrial homeostasis. In addition to its canonical role in crista membrane structure, MIC60 regulates mitochondrial motility, likely by influencing protein levels of the outer mitochondrial membrane protein Miro that anchors mitochondria to the microtubule motors. Loss of MIC60 causes loss of Miro and mitochondrial arrest. At a cellular level, loss of MIC60 disrupts synaptic structure and function at the neuromuscular junctions. The dual roles of MIC60 in both mitochondrial crista structure and motility position it as a crucial player for cellular integrity and survival.

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