Chordin and noggin promote organizing centers of forebrain development in the mouse

Development ◽  
2002 ◽  
Vol 129 (21) ◽  
pp. 4975-4987 ◽  
Author(s):  
Ryan M. Anderson ◽  
Alison R. Lawrence ◽  
Rolf W. Stottmann ◽  
Daniel Bachiller ◽  
John Klingensmith
Keyword(s):  
Bone Morphogenetic Proteins ◽  
Craniofacial Skeleton ◽  
Neonatal Lethality ◽  
Prechordal Plate ◽  
Organizing Center ◽  
Increased Sensitivity ◽  
Bmp Antagonists ◽  
The Brain

In this study we investigate the roles of the organizer factors chordin and noggin, which are dedicated antagonists of the bone morphogenetic proteins(BMPs), in formation of the mammalian head. The mouse chordin and noggin genes(Chrd and Nog) are expressed in the organizer (the node) and its mesendodermal derivatives, including the prechordal plate, an organizing center for rostral development. They are also expressed at lower levels in and around the anterior neural ridge, another rostral organizing center. To elucidate roles of Chrd and Nog that are masked by the severe phenotype and early lethality of the double null, we have characterized embryos of the genotype Chrd-/-;Nog+/-. These animals display partially penetrant neonatal lethality, with defects restricted to the head. The variable phenotypes include cyclopia,holoprosencephaly, and rostral truncations of the brain and craniofacial skeleton. In situ hybridization reveals a loss of SHH expression and signaling by the prechordal plate, and a decrease in FGF8 expression and signaling by the anterior neural ridge at the five-somite stage. DefectiveChrd-/-;Nog+/- embryos exhibit reduced cell proliferation in the rostral neuroepithelium at 10 somites, followed by increased cell death 1 day later. Because these phenotypes result from reduced levels of BMP antagonists, we hypothesized that they are due to increased BMP activity. Ectopic application of BMP2 to wild-type cephalic explants results in decreased FGF8 and SHH expression in rostral tissue, suggesting that the decreased expression of FGF8 and SHH observed in vivo is due to ectopic BMP activity. Cephalic explants isolated from Chrd;Nog double mutant embryos show an increased sensitivity to ectopic BMP protein, further supporting the hypothesis that these mutants are deficient in BMP antagonism. These results indicate that the BMP antagonists chordin and noggin promote the inductive and trophic activities of rostral organizing centers in early development of the mammalian head.

Antibodies to β-Amyloid Decrease the Blood-to-Brain Transfer of β-Amyloid Peptide1

2002 ◽  
Vol 227 (8) ◽  
pp. 609-615 ◽  
Author(s):  
Weihong Pan ◽  
Beka Solomon ◽  
Lawrence M. Maness ◽  
Abba J. Kastin
Keyword(s):  
Ex Vivo ◽  
Amyloid Β ◽  
Brain Perfusion ◽  
Brain Parenchyma ◽  
Amyloid Angiopathy ◽  
Β Amyloid ◽  
Blocking Antibodies ◽  
The Brain

Amyloid-β peptides (Aβ) play an important role in the pathophysiology of dementia of the Alzheimer's type and in amyloid angiopathy. Aβ outside the CNS could contribute to plaque formation in the brain where its entry would involve interactions with the blood-brain barrier (BBB). Effective antibodies to Aβ have been developed in an effort to vaccinate against Alzheimer's disease. These antibodies could interact with Aβ in the peripheral blood, block the passage of Aβ across the BBB, or prevent Aβ deposition within the CNS. To determine whether the blocking antibodies act at the BBB level, we examined the influx of radiolabeled Aβ (125I-Aβ1-40) into the brain after ex-vivo incubation with the antibodies. Antibody mAb3D6 (élan Company) reduced the blood-to-brain influx of Aβ after iv bolus injection. It also significantly decreased the accumulation of Aβ in brain parenchyma. To confirm the in-vivo study and examine the specificity of mAb3D6, in-situ brain perfusion in serum-free buffer was performed after incubation of 125I-Aβ1-40 with another antibody mAbmc1 (DAKO Company). The presence of mAbmc1 also caused significant reduction of the influx of Aβ into the brain after perfusion. Therefore, effective antibodies to Aβ can reduce the influx of Aβ1-40 into the brain.

scholarly journals Increased Severity of Local and Systemic Anaphylactic Reactions in Gp49b1-Deficient Mice

2001 ◽  
Vol 194 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Massoud Daheshia ◽  
Daniel S. Friend ◽  
Michael J. Grusby ◽  
K. Frank Austen ◽  
Howard R. Katz
Keyword(s):  
Mast Cell ◽  
Cell Activation ◽  
Mast Cell Activation ◽  
Critical Question ◽  
Increased Sensitivity ◽  
Antibody Levels ◽  
Deficient Mice

gp49B1 is an immunoglobulin (Ig) superfamily member that inhibits FcεRI-induced mast cell activation when the two receptors are coligated with antibodies in vitro. The critical question of in vivo function of gp49B1 is now addressed in gene-disrupted mice. gp49B1-deficient mice exhibited a significantly increased sensitivity to IgE-dependent passive cutaneous anaphylaxis as assessed by greater tissue swelling and mast cell degranulation in situ. Importantly, by the same criteria, the absence of gp49B1 also resulted in a lower threshold for antigen challenge in active cutaneous anaphylaxis, in which the antigen-specific antibody levels were comparable in gp49B1-deficient and sufficient mice. Moreover, the absence of gp49B1 resulted in a significantly greater and faster death rate in active systemic anaphylaxis. These results indicate that gp49B1 innately dampens adaptive immediate hypersensitivity responses by suppressing mast cell activation in vivo. In addition, this study provides a new concept and target for regulation of allergic disease susceptibility and severity.

A potential artifact in use of a new technique for rapid brain removal.

1978 ◽  
Vol 234 (4) ◽  
pp. E365
Author(s):  
K L Wong ◽  
G M Tyce
Keyword(s):  
Blood Glucose ◽  
Brain Tissue ◽  
Plasma Levels ◽  
Postmortem Changes ◽  
New Techniques ◽  
Animal Brain ◽  
A New Technique ◽  
The Brain

New techniques are are continuously being developed to obtain animal brain tissue that is as close as possible to its in vivo status. The brain-blowing technique provides a swift freezing of brain tissue (within 1 s) in which postmortem changes have been said to be minimal. Higher concentrations of glucose were present in brain samples removed by this method than have previously been found when the brain was frozen in situ, but at the same time the plasma levels of glucose were higher. It is suggested that, although the procedure did not appear to involve any stress, the hyperglycemia was stress related. Modifications of the procedure are described, by which these changes in blood glucose have been minimized.

scholarly journals In vivo activity of glutaminase in the brain of hyperammonaemic rats measured by 15N nuclear magnetic resonance

1995 ◽  
Vol 305 (1) ◽  
pp. 329-336 ◽  
Author(s):  
K Kanamori ◽  
B D Ross
Keyword(s):  
Brain Homogenate ◽  
Inhibitory Effect ◽  
Intact Brain ◽  
Strong Inhibitory Effect ◽  
Glutamine Synthesis ◽  
Gaba Synthesis ◽  
The Brain

The in vivo activity of phosphate-activated glutaminase (PAG) was measured in the brain of hyperammonaemic rat by 15N n.m.r. Brain glutamine was 15N-enriched by intravenous infusion of 15NH4+ until the concentration of [5-15N]glutamine reached 6.1 mumol/g. Further glutamine synthesis was inhibited by intraperitoneal injection of methionine-DL-sulphoximine, an inhibitor of glutamine synthetase, and the infusate was changed to 14NH4+ during observation of decrease in brain [5-15N]glutamine due to PAG and other glutamine utilization pathways. Progressive decrease in brain [5-15N]glutamine, PAG-catalysed production of 15NH4+ and its subsequent assimilation into glutamate by glutamate dehydrogenase were monitored in vivo by 15N n.m.r. Brain [5-15N]glutamine (15N enrichment of 0.35-0.50) decreased at a rate of 1.2 mumol/h per g of brain. The in vivo PAG activity, determined from the observed rate and the quantity of 15NH4+ produced and subsequently assimilated into glutamate and aspartate, was 0.9-1.3 mumol/h per g. This activity is less than 1.1% of the reported activity in vitro measured in rat brain homogenate at a 10 mM concentration of the activator Pi. Inhibition by ammonia (brain level 1.4 mumol/g) alone does not account for the observed low activity in vivo. The result strongly suggests that, in intact brain, PAG activity is maintained at a low level by a suboptimal in situ concentration of Pi and the strong inhibitory effect of glutamate. The observed PAG activity in vivo is lower than the reported in vivo activity of glutamate decarboxylase which converts glutamate into gamma-aminobutyrate (GABA). The result suggests that PAG-catalysed hydrolysis of glutamine is not the sole provider of glutamate used for GABA synthesis.

Electrochemical Detection of Neurotransmitters in the Brain and Other Molecules with Biological Activity in the Nervous System: Dopamine Analysis

2020 ◽  
Vol 24 (21) ◽  
pp. 2498-2507
Author(s):  
Erika Bustos ◽  
Juan Manríquez ◽  
Ana Laura Colín-González ◽  
Edgar Rangel-López ◽  
Abel Santamaría
Keyword(s):  
Nervous System ◽  
Biological Activity ◽  
Electrochemical Detection ◽  
Neurological Diseases ◽  
Electrochemical Techniques ◽  
Modified Electrodes ◽  
Analytical Techniques ◽  
The Brain

Monitoring the appropriate functions of the brain is a priority when the diagnosis of neurological diseases is carried out. In this regard, there are different analytical techniques to detect neurotransmitters and other molecules with biological activity in the nervous system. Among several analytical procedures, electrochemical techniques are very important since they can be applied in situ, without loss of sensibility and/or minimal handling of samples. In addition, it is also possible to combine them with specific detectors designed on the basis of chemically-modified electrodes in order to improve detection limits by promoting molecular recognition capabilities at their surfaces, thus favoring the development of electrochemical detection in vivo by microelectrodes. In this mini-review, we will describe the major characteristics of this analytical method and its advantages for the detection of neurotransmitters (mostly dopamine) in vivo.

scholarly journals Simple epithelium keratins 8 and 18 provide resistance to Fas-mediated apoptosis. The protection occurs through a receptor-targeting modulation

2001 ◽  
Vol 154 (4) ◽  
pp. 763-774 ◽  
Author(s):  
Stéphane Gilbert ◽  
Anne Loranger ◽  
Nathalie Daigle ◽  
Normand Marceau
Keyword(s):  
Fas Ligand ◽  
Surface Membrane ◽  
Null Mouse ◽  
Agonistic Antibody ◽  
Tnf Α ◽  
Increased Sensitivity ◽  
Mouse Hepatocytes ◽  
Necrosis Factor

Keratins 8 and 18 belong to the keratin family of intermediate filament (IF) proteins and constitute a hallmark for all simple epithelia, including the liver. Hepatocyte IFs are made solely of keratins 8 and 18 (K8/K18). In these cells, the loss of one partner via a targeted null mutation in the germline results in hepatocytes lacking K8/K18 IFs, thus providing a model of choice for examining the function(s) of simple epithelium keratins. Here, we report that K8-null mouse hepatocytes in primary culture and in vivo are three- to fourfold more sensitive than wild-type (WT) mouse hepatocytes to Fas-mediated apoptosis after stimulation with Jo2, an agonistic antibody of Fas ligand. This increased sensitivity is associated with a higher and more rapid caspase-3 activation and DNA fragmentation. In contrast, no difference in apoptosis is observed between cultured K8-null and WT hepatocytes after addition of the Fas-related death-factors tumor necrosis factor (TNF) α or TNF-related apoptosis-inducing ligand. Analyses of the Fas distribution in K8-null and WT hepatocytes in culture and in situ demonstrate a more prominent targeting of the receptor to the surface membrane of K8-null hepatocytes. Moreover, altering Fas trafficking by disrupting microtubules with colchicine reduces by twofold the protection generated against Jo2-induced lethal action in K8-null versus WT hepatocytes. Together, the results strongly suggest that simple epithelium K8/K18 provide resistance to Fas-mediated apoptosis and that this protection occurs through a modulation of Fas targeting to the cell surface.

scholarly journals Aberrant Calcium Signals in Reactive Astrocytes: A Key Process in Neurological Disorders

2019 ◽  
Vol 20 (4) ◽  
pp. 996 ◽  
Author(s):  
Eiji Shigetomi ◽  
Kozo Saito ◽  
Fumikazu Sano ◽  
Schuichi Koizumi
Keyword(s):  
Neurological Disorders ◽  
Molecular Mechanisms ◽  
Brain Disease ◽  
Reactive Astrocytes ◽  
Brain Functions ◽  
Progression Of Disease ◽  
Brain Insults ◽  
The Brain

Astrocytes are abundant cells in the brain that regulate multiple aspects of neural tissue homeostasis by providing structural and metabolic support to neurons, maintaining synaptic environments and regulating blood flow. Recent evidence indicates that astrocytes also actively participate in brain functions and play a key role in brain disease by responding to neuronal activities and brain insults. Astrocytes become reactive in response to injury and inflammation, which is typically described as hypertrophy with increased expression of glial fibrillary acidic protein (GFAP). Reactive astrocytes are frequently found in many neurological disorders and are a hallmark of brain disease. Furthermore, reactive astrocytes may drive the initiation and progression of disease processes. Recent improvements in the methods to visualize the activity of reactive astrocytes in situ and in vivo have helped elucidate their functions. Ca2+ signals in reactive astrocytes are closely related to multiple aspects of disease and can be a good indicator of disease severity/state. In this review, we summarize recent findings concerning reactive astrocyte Ca2+ signals. We discuss the molecular mechanisms underlying aberrant Ca2+ signals in reactive astrocytes and the functional significance of aberrant Ca2+ signals in neurological disorders.

scholarly journals Neuropeptide Y Cells Represent a Distinct Glucose-Sensing Population in the Lateral Hypothalamus

Endocrinology ◽  
2011 ◽  
Vol 152 (11) ◽  
pp. 4046-4052 ◽  
Author(s):  
Oliver J. Marston ◽  
Paul Hurst ◽  
Mark L. Evans ◽  
Denis I. Burdakov ◽  
Lora K. Heisler
Keyword(s):  
Electrical Activity ◽  
Neuropeptide Y ◽  
Fluorescent Protein ◽  
Regulatory Elements ◽  
Glucose Sensing ◽  
Hypothalamic Area ◽  
Extracellular Glucose ◽  
The Brain

The maintenance of appropriate glucose levels is necessary for survival. Within the brain, specialized neurons detect glucose fluctuations and alter their electrical activity. These glucose-sensing cells include hypothalamic arcuate nucleus neurons expressing neuropeptide Y (NPY) and lateral hypothalamic area (LHA) neurons expressing orexin/hypocretins (ORX) or melanin-concentrating hormone (MCH). Within the LHA, a population of NPY-expressing cells exists; however, their ability to monitor energy status is unknown. We investigated whether NPY neurons located in the LHA, a classic hunger center, detect and respond to fluctuations in glucose availability and compared these responses with those of known LHA glucose sensors expressing ORX or MCH. Using mice expressing green fluorescent protein under the control of NPY regulatory elements, we identified LHA NPY cells and explored their anatomical distribution, neurochemical and electrical properties, in vivo responses to fasting and insulin-induced hypoglycemia, and in situ electrical responses to extracellular glucose. We report that NPY, ORX, and MCH are expressed in nonoverlapping populations within the LHA. Subpopulations of LHA NPY neurons were activated in vivo by both a 6-h fast and insulin-induced hypoglycemia. Likewise, increased extracellular glucose suppressed the electrical activity of approximately 70% of LHA NPY neurons in situ, eliciting hyperpolarization and activating background K+ currents. Furthermore, we report that the glucose sensitivity of LHA NPY neurons is significantly different from neighboring ORX and MCH neurons. These data suggest that NPY-expressing cells in the LHA are a novel population of glucose-sensing neurons that represent a new player in the brain circuitry integrating information about glucose homeostasis.

scholarly journals Neuroprotective Effect of Ultrasound Triggered Astaxanthin Release Nanoparticles on Early Brain Injury After Subarachnoid Hemorrhage

2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Cai ◽  
Qi Wu ◽  
Zhi Zhong Yan ◽  
Wei-Zhen He ◽  
Xiao-Ming Zhou ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Subarachnoid Hemorrhage ◽  
Neuroprotective Effect ◽  
Early Brain Injury ◽  
Signal Pathways ◽  
Triggered Release ◽  
Brain Oxidative Stress ◽  
The Brain

Subarachnoid hemorrhage (SAH) is a fatal disease. Within 72 h of SAH, the intracranial blood-brain barrier (BBB) is destroyed, and the nerve cells have responses such as autophagy, apoptosis, and oxidative stress. Antioxidation is an essential treatment of SAH. Astaxanthin (ATX) induces cells’ antioxidant behaviors by regulating related signal pathways to reduce the damage of brain oxidative stress, inflammation, and apoptosis. Because of its easy degradability and low bioavailability, ATX is mainly encapsulated with stimulus-responsive nanocarriers to improve its stability, making it rapidly release in the brain and efficiently enter the lesion tissue. In this study, the ultrasonic cavitation agent perfluorocarbon (PFH), ATX, and fluorescent dye IR780 were loaded with polydopamine (PDA) to prepare a US triggered release nanoparticles (AUT NPs). The core-shell structure of AUT NPs formed a physical barrier to improve the bioavailability of ATX. AUT NPs have high ATX loading capacity and US responsiveness. The experimental results show that the AUT NPs have high stability in the physiological environment. Both US and pH stimuli can trigger the release. Under US, PFH breaks through the rigid shell. The structure of AUT NPs is destroyed in situ, releasing the loaded drugs into neuronal cells to realize the antioxidant and antiapoptotic effects. The in vivo experiment results show that the AUT NPs have good biosafety. They release the drugs in the brain under stimuli. The in vivo treatment results also show that AUT NPs have an excellent therapeutic effect. This approach presents an experimental basis for the establishment of Innovative SAH treatments.

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