scholarly journals SUN-260 Dual Role of Carboxypeptidase E in Prohormone Processing and a Novel Neurotrophic Factor Mediating Neuroprotection and Cognitive Functions in Hippocampal CA3 Neurons in Mice

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Lan Xiao ◽  
Vinay Sharma ◽  
Leila Toulabi ◽  
Xuyu Yang ◽  
Cheol Lee ◽  
...  
Keyword(s):  
Neurotrophic Factor ◽  
Neuronal Degeneration ◽  
Tyrosine Kinase Receptor ◽  
Wild Type ◽  
Prohormone Processing ◽  
Hippocampal Ca3 ◽  
Ca3 Neurons ◽  
The Brain

Abstract Stress causes release of glucocorticoids from the adrenals which then circulate to the brain. High concentrations glucocorticoid from chronic severe stress results in pathophysiology in the brain, including neuronal degeneration, cell death and cognitive dysfunction, leading to diseases such as Alzheimer Disease and Major Depressive Disorders. Neurotrophic/growth factors such as BDNF, NGF and NT3 have been linked to these pathological conditions. Carboxypeptidase E (CPE), a proneuropeptide/prohormone processing enzyme, also named neurotrophic factor-α1(NFα1) is highly expressed in the stress-vulnerable hippocampal CA3 neurons, and was shown to have neuroprotective activity from in vitro studies. Here we investigated if CPE-NFα1 functions in vivo, independent of its enzymatic activity, and the mechanism underlying its action. We generated knock-in mice expressing a non-enzymatic form of CPE, CPE-E342Q, but not wild-type CPE. The CPE-E342Q mice showed significantly decreased neuropeptide content and exhibited obesity, diabetes and infertility due to lack of prohormone processing activity, similar to CPE-KO mice. However, they showed no hippocampal CA3 degeneration, exhibited neurogenesis in the dentate gyrus, and displayed normal spatial learning and memory, similar to CPE wild-type mice, after weaning stress; unlike CPE-KO mice which showed hippocampal CA3 neuronal degeneration and cognitive deficits. Binding studies showed that radiolabeled CPE bound hippocampal cell membrane specifically, in a saturable manner. Binding of CPE and CPE-E342Q to hippocampal neurons activated Erk signaling and pre-treatment with either of these proteins protected neurons against H2O2- or glutamate-induced neurotoxcity by increasing BCL2 expression. In vitro and in vivo inhibitor studies demonstrated that this neuroprotective effect was independent of tyrosine kinase receptor signaling. Taken together, the data provide evidence that CPE-NFα1 is a unique neurotrophic factor which acts through a non-tyrosine kinase receptor to activate Erk-BCL2 signaling to protect hippocampal CA3 neurons against stress-induced neurodegeneration and maintaining normal cognitive functions in mice.

scholarly journals DJ-1 regulates the integrity and function of ER-mitochondria association through interaction with IP3R3-Grp75-VDAC1

2019 ◽  
Vol 116 (50) ◽  
pp. 25322-25328 ◽  
Author(s):  
Yi Liu ◽  
Xiaopin Ma ◽  
Hisashi Fujioka ◽  
Jun Liu ◽  
Shengdi Chen ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Cellular Mechanism ◽  
Loss Of Function ◽  
Wild Type ◽  
Calcium Efflux ◽  
And Function ◽  
The Brain ◽  
Early Onset Parkinson’S Disease

Loss-of-function mutations in DJ-1 are associated with autosomal recessive early onset Parkinson’s disease (PD), yet the underlying pathogenic mechanism remains elusive. Here we demonstrate that DJ-1 localized to the mitochondria-associated membrane (MAM) both in vitro and in vivo. In fact, DJ-1 physically interacts with and is an essential component of the IP3R3-Grp75-VDAC1 complexes at MAM. Loss of DJ-1 disrupted the IP3R3-Grp75-VDAC1 complex and led to reduced endoplasmic reticulum (ER)-mitochondria association and disturbed function of MAM and mitochondria in vitro. These deficits could be rescued by wild-type DJ-1 but not by the familial PD-associated L166P mutant which had demonstrated reduced interaction with IP3R3-Grp75. Furthermore, DJ-1 ablation disturbed calcium efflux-induced IP3R3 degradation after carbachol treatment and caused IP3R3 accumulation at the MAM in vitro. Importantly, similar deficits in IP3R3-Grp75-VDAC1 complexes and MAM were found in the brain of DJ-1 knockout mice in vivo. The DJ-1 level was reduced in the substantia nigra of sporadic PD patients, which was associated with reduced IP3R3-DJ-1 interaction and ER-mitochondria association. Together, these findings offer insights into the cellular mechanism in the involvement of DJ-1 in the regulation of the integrity and calcium cross-talk between ER and mitochondria and suggests that impaired ER-mitochondria association could contribute to the pathogenesis of PD.

Effects of Short Duration Overpressure on Astrocytes: An In Vitro Study

2007 ◽  
Author(s):  
Lai Yee Leung ◽  
Pamela J. VandeVord ◽  
Warren Hardy ◽  
Roche De Guzman ◽  
King H. Yang ◽  
...  
Keyword(s):  
Short Duration ◽  
Neuronal Degeneration ◽  
In Vitro Study ◽  
Underlying Mechanism ◽  
Blast Waves ◽  
Body Armor ◽  
The Brain ◽  
Physiological Systems

Blast wave overpressure from detonations can injure physiological systems ‘silently.’ Experimental and clinical studies have revealed the damaging effects of shock waves on different physiological systems, such as ears, lungs and gastrointestinal tracts [1, 2]. Despite the improved helmet and body armor, many veterans returning from wars suffered from neurological disorders that are being diagnosed as mild traumatic brain injury. Warden (2006) reported that most of these veterans were exposed to blast [3]. In vivo study illustrated neuronal degeneration in the brain after exposure to blast waves [4]. As with many neuronal diseases, blast-induced neuronal injury may be related to microglia and astrocyte activation. However, the underlying mechanism is not clearly understood. This study was aimed at investigating the effects of short duration overpressure on astrocytes, in terms of cell proliferation and mRNA expression of several apoptotic genes and glial fibrillary acidic protein (GFAP).

scholarly journals Preclinical characterization of [18F]T-008, a novel PET imaging radioligand for cholesterol 24-hydroxylase

2021 ◽  
Author(s):  
Tatsuki Koike ◽  
Cristian C. Constantinescu ◽  
Shuhei Ikeda ◽  
Toshiya Nishi ◽  
Eiji Sunahara ◽  
...  
Keyword(s):  
Mouse Brain ◽  
Pet Imaging ◽  
Rank Order ◽  
Cholesterol Homeostasis ◽  
Dependent Manner ◽  
Wild Type ◽  
In Vivo Evaluation ◽  
The Brain

Abstract Purpose Cholesterol 24-hydroxylase (CH24H) is a brain-specific enzyme that plays a major role in brain cholesterol homeostasis by converting cholesterol into 24S-hydroxycholesterol. The selective CH24H inhibitor soticlestat (TAK-935) is being pursued as a drug for treatment of seizures in developmental and epileptic encephalopathies. Herein, we describe the successful discovery and the preclinical validation of the novel radiolabeled CH24H ligand (3-[18F]fluoroazetidin-1-yl){1-[4-(4-fluorophenyl)pyrimidin-5-yl]piperidin-4-yl}methanone ([18F]T-008) and its tritiated analog, [3H]T-008. Methods In vitro autoradiography (ARG) studies in the CH24H wild-type (WT) and knockout (KO) mouse brain sections were conducted using [3H]T-008. PET imaging was conducted in two adult rhesus macaques using [18F]T-008. Each macaque received two test–retest baseline scans and a series of two blocking doses of soticlestat administered prior to [18F]T-008 to determine the CH24H enzyme occupancy. PET data were analyzed with Logan graphical analysis using plasma input. A Lassen plot was applied to estimate CH24H enzyme occupancy by soticlestat. Results In ARG studies, binding of [3H]T-008 was specific to CH24H in the mouse brain sections, which was not observed in CH24H KO or in wild-type mice after pretreatment with soticlestat. In rhesus PET studies, the rank order of [18F]T-008 uptake was striatum > cortical regions > cerebellum, which was consistent with CH24H distribution in the brain. Pre-blocking with soticlestat reduced the maximum uptake and increased the washout in all brain regions in a dose-dependent manner. Calculated global occupancy values for soticlestat at a dose of 0.89 mg/kg were 97–98%, indicating maximum occupancy. Conclusion The preclinical in vitro and in vivo evaluation of labeled T-008 demonstrates that [18F]T-008 is suitable for imaging CH24H in the brain and warrants further studies in humans. Graphical abstract

scholarly journals Innate STAT1-Dependent Genomic Response of Neurons to the Antiviral Cytokine Alpha Interferon

2005 ◽  
Vol 79 (13) ◽  
pp. 8295-8302 ◽  
Author(s):  
Jianping Wang ◽  
Iain L. Campbell
Keyword(s):  
Viral Infection ◽  
Lymphocytic Choriomeningitis ◽  
Gene Chip ◽  
Neuronal Cultures ◽  
Wild Type ◽  
Rnase Protection ◽  
The Brain ◽  
Genomic Response

ABSTRACT Alpha/beta interferons (IFNs-α/β) are cytokines that play an essential role in the host defense against viral infection. Our previous studies have shown that the key IFN signaling molecule STAT1 is highly elevated and activated in central nervous system neurons during viral infection and in transgenic mice with astrocyte production of IFN-α (glial fibrillary acidic protein [GFAP]-IFN-α), suggesting that neurons are a very responsive target cell population for IFNs. To elucidate the genomic response of neurons to IFN-α, we undertook studies both in vitro and in vivo. Gene chip analysis was applied to RNA from IFN-α-treated or untreated primary cortical neuronal cultures derived from embryonic day 15 fetal wild-type or STAT1 knockout (KO) mice. The expression of 51 known and 5 unknown genes was increased significantly by more than twofold after exposure of wild-type but not STAT1 KO neurons to IFN-α. Some more highly expressed genes included IFN-induced 15-kDa protein, ubiquitin-specific protease 18, glucocorticoid attenuated response genes, IFN-induced GTPases, and the chemokine CXCL10. For several of these genes, the gene chip findings were confirmed by RNase protection assays. In addition, examination of the expression of some of these selected genes revealed that they were increased in neurons in the brain of either GFAP-IFN-α mice or mice infected with lymphocytic choriomeningitis virus. In conclusion, our study revealed a robust STAT1-dependent genomic response of neurons to IFN-α, highlighting an innate potential of these cells to defend against viral infection in the brain.

Mice that lack astrotactin have slowed neuronal migration

Development ◽  
2002 ◽  
Vol 129 (4) ◽  
pp. 965-972 ◽  
Author(s):  
Niels C. Adams ◽  
Toshifumi Tomoda ◽  
Margaret Cooper ◽  
Gunnar Dietz ◽  
Mary E. Hatten
Keyword(s):  
Neuronal Migration ◽  
Abnormal Development ◽  
Wild Type ◽  
Migration Rates ◽  
Targeted Gene Disruption ◽  
Cell Assays ◽  
Cortical Regions ◽  
The Brain

The cortical regions of the brain are laminated as a result of directed migration of precursor cells along glia during development. Previously, we have used an assay system to identify astrotactin as a neuronal ligand for migration on glial fibers. To examine the function of astrotactin in vivo, we generated a null mutation by targeted gene disruption. The cerebella of astrotactin null mice are approximately 10% smaller than wild type. In vitro and in vivo cerebellar granule cell assays show a decrease in neuron-glial binding, a reduction in migration rates and abnormal development of Purkinje cells. Consequences of this are poorer balance and coordination. Thus, astrotactin functions in migration along glial processes in vivo, a process required for generating laminar structures and for the development of synaptic partner systems.

Cyclosporin A, a P-gp Inhibitor, Augments the Anti-Central Nervous System Ph+ Leukemia Effects of INNO-406.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 834-834
Author(s):  
Asumi Yokota ◽  
Shinya Kimura ◽  
Satohiro Masuda ◽  
Eishi Ashihara ◽  
Yoshimasa Urasaki ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cyclosporin A ◽  
Leukemic Cells ◽  
Wild Type ◽  
Intracellular Accumulation ◽  
Cns Relapse ◽  
The Brain

Abstract Central nervous system (CNS) relapse accompanying prolonged administration of imatinib mesylate, an Abl-specific tyrosine kinase inhibitor, has recently become apparent as an impediment to the therapy of Philadelphia-chromosome-positive (Ph+) leukemia. CNS relapse may be explained by limited penetration of imatinib into the cerebrospinal fluid due to presence of P-glycoprotein (P-gp) at blood-brain barrier. To overcome imatinib-resistance mechanisms such as bcr-abl gene amplification, point mutations within ABL kinase domain, and activation of Lyn, we recently developed a specific dual BCR-ABL/Lyn inhibitor, INNO-406 (formerly NS-187), which is 25–55 times more potent than imatinib in vitro and at least 10 times more potent in vivo (Blood106: 3948–3954, 2005). The aim of this study was to investigate the efficacy of INNO-406 in treating CNS Ph+ leukemia. The intracellular accumulation of [14C]INNO-406 in P-gp overexpressing LLC-GA5-COL150 cells was much less than that in parental LLC-PK1 cells. The addition of 10 mM cyclosporin A (CsA) increased the intracellular accumulation of [14C]INNO-406 in both LLC-PK1 cells and LLC-GA5-COL150 cells. The peak concentration of INNO-406 in the brain when 30 mg/kg INNO-406 was administered p.o. was 50 ng/ g (87 nM), representing only 10% of plasma drug level. These findings suggested that INNO-406 is also a substrate of P-gp, as is imatinib. However, the residual concentration of INNO-406 in the CNS was enough to inhibit the growth of Ph+ leukemic cells according to the in vitro data. To increase the concentration of INNO-406 in CNS, we next examined the combined effects of CsA. In the brain, the concentration of INNO-406 was doubled following prior administration of 50 mg/kg CsA. Since pharmacokinetic studies suggested the possible effects of INNO-406 against CNS Ph+ leukemia, we investigated in vivo anti-CNS Ph+ leukemia effects of INNO-406 alone and combination of INNO-406 and CsA using immunodeficient mice (nude or NOD/SCID) which received Ph+ leukemic cells into the cerebral ventricle. INNO-406 alone inhibited growth of leukemic cells harboring either wild type or mutated BCR-ABL such as E255K and M351T in CNS. Furthermore, CsA significantly enhanced anti-CNS Ph+ leukemia effects of INNO-406 in vivo not only against cells harboring wild type BCR-ABL but also against cells harboring BCR-ABL/M351T (Figure). In conclusion, INNO-406 was found to inhibit Ph+ leukemic cell growth in CNS in spite of efflux of the compound by P-gp, and CsA augmented the anti-CNS Ph+ leukemia effects of INNO-406. Phase I clinical study on INNO-406 was initiated in the U.S.A. in July 2006. The efficacy and safety of INNO-406 in the treatment of leukemias is expected to be verified by early-phase clinical trials. Figure Figure

scholarly journals Glycoprotein D of Bovine Herpesvirus 5 (BoHV-5) Confers an Extended Host Range to BoHV-1 but Does Not Contribute to Invasion of the Brain

2010 ◽  
Vol 84 (11) ◽  
pp. 5583-5593 ◽  
Author(s):  
Evgeni Gabev ◽  
Kurt Tobler ◽  
Carlos Abril ◽  
Monika Hilbe ◽  
Claudia Senn ◽  
...  
Keyword(s):  
Host Range ◽  
Bovine Herpesvirus ◽  
Wild Type ◽  
Bovine Herpesvirus 1 ◽  
High Incidence ◽  
Herpesvirus 1 ◽  
Virulent Phenotype ◽  
The Brain

ABSTRACT Bovine herpesvirus 1 (BoHV-1) and BoHV-5 are closely related pathogens of cattle, but only BoHV-5 is considered a neuropathogen. We engineered intertypic gD exchange mutants with BoHV-1 and BoHV-5 backbones in order to address their in vitro and in vivo host ranges, with particular interest in invasion of the brain. The new viruses replicated in cell culture with similar dynamics and to titers comparable to those of their wild-type parents. However, gD of BoHV-5 (gD5) was able to interact with a surprisingly broad range of nectins. In vivo, gD5 provided a virulent phenotype to BoHV-1 in AR129 mice, featuring a high incidence of neurological symptoms and early onset of disease. However, only virus with the BoHV-5 backbone, independent of the gD type, was detected in the brain by immunohistology. Thus, gD of BoHV-5 confers an extended cellular host range to BoHV-1 and may be considered a virulence factor but does not contribute to the invasion of the brain.

Recombinant Human Ciliary Neurotrophic Factor Protects MCAO/R Rat Brain against Neuronal Degeneration and Apoptosis by Regulating NOS Expression

2013 ◽  
Vol 699 ◽  
pp. 354-359
Author(s):  
Qing Shan Liu ◽  
Zi Qian Zhang ◽  
Xiao Yu Chen ◽  
Duo Ming Zhao ◽  
Yun Xia Duan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Neurotrophic Factor ◽  
Ischemia Reperfusion Injury ◽  
Neuronal Degeneration ◽  
Ischemia Reperfusion ◽  
Glucose Deprivation ◽  
Ciliary Neurotrophic Factor ◽  
Neuronal Cultures

To research the effects and mechanisms of recombinant human ciliary neurotrophic factor (rhCNTF) on ischemia/reperfusion in vivo and in vitro, rhCNTF was biosynthesized, and ischemia/reperfusion-like models were used. Protection by rhCNTF was studied at the in vivo level using a model of middle cerebral artery occlusion and reperfusion (MCAO/R) in rats. RhCNTF was administrated just before reperfusion. RhCNTF markedly increased animal viability, decreased infarct volumes and neurological deficit scores. Primary cortical neuronal cultures were subjected to oxygen-glucose deprivation/reoxygenation, and treated with rhCNTF prophylactically. Results indicated that neuronal survival rates were increased, LDH release was decreased and lose of neurite length were alleviated in rhCNTF group, and this protection was associated with nerotrophic effect, nitric oxide and neuronal nitric oxide synthase (nNOS) and inducible NOS (iNOS). The data suggest that rhCNTF may be a good therapeutic reagent to reduce cerebral ischemia/reperfusion injury, and may act by NOS regulation.

scholarly journals The role of the efflux transporter P-glycoprotein in brain penetration of prednisolone

2002 ◽  
Vol 175 (1) ◽  
pp. 251-260 ◽  
Author(s):  
AM Karssen ◽  
OC Meijer ◽  
IC van der Sandt ◽  
AG De Boer ◽  
EC De Lange ◽  
...  
Keyword(s):  
Efflux Transporter ◽  
Wild Type ◽  
Corticosteroid Receptors ◽  
P Glycoprotein ◽  
Human Mdr1 ◽  
The Brain ◽  
Synthetic Glucocorticoid

In the present study, we have investigated the role of the multidrug resistance (mdr) P-glycoprotein (Pgp) at the blood-brain barrier in hampering the access of the synthetic glucocorticoid, prednisolone. In vivo, a tracer dose of [(3)H]prednisolone poorly penetrated the brain of adrenalectomised wild-type mice, but the uptake was more than threefold enhanced in the absence of Pgp expression in mdr1a (-/-) mice. In vitro, in stably transfected LLC-PK1 monolayers the human MDR1 P-glycoprotein was able to transport prednisolone present at a micromolar concentration. A specific Pgp blocker, LY 335979, could block this polar transport of [(3)H]prednisolone. Human Pgp does not transport all steroids, as cortexolone was not transported at all and aldosterone was only weakly transported. The ability of Pgp to export the synthetic glucocorticoid, prednisolone, suggests that uptake of prednisolone in the human brain is impaired, leading to a discrepancy between central and peripheral actions. Furthermore, the ensuing imbalance in activation of the two types of brain corticosteroid receptors may have consequences for cognitive performance and mood.

Effect of pH and inhibitors on beta-amyloid fibril assembly

1996 ◽  
Vol 54 ◽  
pp. 752-753
Author(s):  
Beverly E. Maleeff ◽  
Timothy K. Hart ◽  
Stephen J. Wood ◽  
Ronald Wetzel
Keyword(s):  
Amyloid Fibril ◽  
Peptide Fragment ◽  
Hydrophobic Peptides ◽  
Amyloid Fibril Formation ◽  
Effects Of Ph ◽  
Severity Of The Disease ◽  
Kinetics Of ◽  
The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

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