Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
Add more filters










Publication year range
1.
Asian Biomed (Res Rev News) ; 17(3): 115-123, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37818161

ABSTRACT

Background: In Japan, on April 20, 2020, the definition of a close contact regarding coronavirus disease (COVID-19) was changed from a long-term contact time to a specified contact time of 15 min and from a contact distance of 2 m to 1 m. Objectives: We aimed to determine the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rate among close contacts of patients with COVID-19 and determine the impact of the infection on transmission among close contacts. Methods: The numbers of SARS-CoV-2 tests, SARS-CoV-2-positive cases, and close contacts of patients with COVID-19 were assessed between March 2020 and February 2021 in Fukui Prefecture, Japan. The study period was subdivided into 3 periods. The second and third period contained data with the changed definition of close contact. Results: Overall, 32,238 SARS-CoV-2 tests were performed. There were 545 patients with COVID-19 and 1487 close contacts, of whom 267 tested positive. The highest infection rate occurred in period 3. Distance, protective measures, and contact time with COVID-19 patients influenced the increased infection rate. The infection rate showed a rising trend from 11.1% in period 1 to 19.2% and 20.0% in periods 2 and 3, respectively (Cochran-Armitage test; P < 0.004). Multivariate analysis revealed that female sex was an independent risk factor for infection of close contacts (odds ratio: 2.23; 95% confidence interval: 1.700-2.930). Conclusions: Female sex is a risk factor for transmission by close contacts. The rate of infection among close contacts may be associated with contact time, contact distance, and protective measures.

2.
Medicine (Baltimore) ; 101(46): e31937, 2022 Nov 18.
Article in English | MEDLINE | ID: mdl-36401462

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic affected the physical and mental health, socioeconomic status, and community behavior of people worldwide. The aim of this retrospective cohort study was to analyze the impact of the COVID-19 pandemic on the oral health and nutritional status of Japanese older adults based on the results of preoperative assessment in patients who underwent total hip or knee arthroplasty under general anesthesia. This study included older adults (≧65 years) who underwent total hip or knee arthroplasty in whom orthopantomography was performed for preoperative oral health assessment, during January 2019 to December 2021. Gender, age, number of family members living together, number of teeth, body mass index, and serum total protein and serum albumin levels were collected for analysis of this study. A total of 201 patients aged 65 to 89 years participated in the study. While the COVID-19 pandemic has had no impact on the oral health status, there has been a drop in serum albumin level from the results of multivariable-adjusted regression analysis considering age, gender, number of family members, and time. The COVID-19 pandemic has affected the serum albumin level of Japanese orthopedic patients aged 65 years or older.


Subject(s)
Arthroplasty, Replacement, Knee , COVID-19 , Humans , Aged , Nutritional Status , COVID-19/epidemiology , Pandemics , Oral Health , Retrospective Studies , Japan/epidemiology , Serum Albumin/metabolism
3.
Arch Oral Biol ; 84: 145-150, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28992600

ABSTRACT

OBJECTIVE: The aim of this study was to investigate the association of tongue brushing with the number of fungiform taste buds and taste perception using a confocal laser scanning microscopy in combination with a filter-paper disc method (FPDM). METHODS: Twenty-four subjects with or without a habit of tongue brushing (11 males and 13 females, 20-46 years old) participated in this study. Nine of the 24 subjects had no habit of tongue brushing (Group 1, n=9). Fifteen subjects had a habit of tongue brushing, and the brushing regions of the tongue were as follows: central region (Group 2, n=7), or entire region (Group 3, n=8) of the tongue dorsum. Using confocal laser scanning microscopy, the average number of taste buds per fungiform papilla (FP) was counted. Taste perception was evaluated using an FPDM. These observations were performed in the midlateral region of the tongue since the distribution of fungiform papillae is large in the midlateral region compared to that in the central region. RESULTS: The subjects in Group 3 showed a significantly decreased number of fungiform taste buds compared to Group 1 and Group 2. Group 3 also showed significantly higher FPDM scores than the other two groups. CONCLUSIONS: Excessive tongue brushing of the entire tongue dorsum, including the midlateral region, may have an association with the decreased number of FP and taste buds and decreased taste sensation. To avoid these conditions, instituting proper tongue brushing methods, such as limiting it to the central region of the tongue and using a light touch, is suggested and is important for the subjects who are eager to participate in tongue brushing.


Subject(s)
Microscopy, Confocal , Oral Hygiene/methods , Taste Buds , Taste Perception , Tongue , Adult , Female , Humans , Male , Middle Aged
4.
Nature ; 500(7460): 45-50, 2013 Aug 01.
Article in English | MEDLINE | ID: mdl-23883936

ABSTRACT

Late-onset Alzheimer's disease (LOAD) risk is strongly influenced by genetic factors such as the presence of the apolipoprotein E ε4 allele (referred to here as APOE4), as well as non-genetic determinants including ageing. To pursue mechanisms by which these affect human brain physiology and modify LOAD risk, we initially analysed whole-transcriptome cerebral cortex gene expression data in unaffected APOE4 carriers and LOAD patients. APOE4 carrier status was associated with a consistent transcriptomic shift that broadly resembled the LOAD profile. Differential co-expression correlation network analysis of the APOE4 and LOAD transcriptomic changes identified a set of candidate core regulatory mediators. Several of these--including APBA2, FYN, RNF219 and SV2A--encode known or novel modulators of LOAD associated amyloid beta A4 precursor protein (APP) endocytosis and metabolism. Furthermore, a genetic variant within RNF219 was found to affect amyloid deposition in human brain and LOAD age-of-onset. These data implicate an APOE4 associated molecular pathway that promotes LOAD.


Subject(s)
Alzheimer Disease/genetics , Apolipoprotein E4/genetics , Genome, Human/genetics , Genomics , Age of Onset , Aged , Alleles , Alzheimer Disease/epidemiology , Amyloid beta-Protein Precursor/metabolism , Brain/drug effects , Brain/metabolism , Cells, Cultured , Cerebral Cortex/metabolism , Endocytosis , Epistasis, Genetic , Female , Fibroblasts , Gene Expression Profiling , Genome-Wide Association Study , Heterozygote , Humans , Levetiracetam , Membrane Glycoproteins/antagonists & inhibitors , Membrane Glycoproteins/genetics , Membrane Glycoproteins/metabolism , Nerve Tissue Proteins/antagonists & inhibitors , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Neurons/drug effects , Neurons/metabolism , Phenotype , Piracetam/analogs & derivatives , Piracetam/pharmacology , Polymorphism, Genetic/genetics , Proteolysis/drug effects , Transcriptome/genetics
5.
Neuron ; 78(6): 957-69, 2013 Jun 19.
Article in English | MEDLINE | ID: mdl-23791192

ABSTRACT

Epigenetic reprogramming of adult human somatic cells to alternative fates, such as the conversion of human skin fibroblasts to induced pluripotency stem cells (iPSC), has enabled the generation of novel cellular models of CNS disorders. Cell reprogramming models appear particularly promising in the context of human neurological disorders of aging such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), for which animal models may not recapitulate key aspects of disease pathology. In addition, recent developments in reprogramming technology have allowed for more selective cell fate interconversion events, as from skin fibroblasts directly to diverse induced neuron (iN) subtypes. Challenges to human reprogramming-based cell models of disease are the heterogeneity of the human population and the extended temporal course of these disorders. A major goal is the accurate modeling of common nonfamilial "sporadic" forms of brain disorders.


Subject(s)
Induced Pluripotent Stem Cells/physiology , Neural Stem Cells/physiology , Neurodegenerative Diseases/pathology , Adult , Animals , Disease Models, Animal , Fibroblasts/pathology , Fibroblasts/physiology , Humans , Induced Pluripotent Stem Cells/pathology , Neural Stem Cells/pathology
6.
Nature ; 488(7413): 652-5, 2012 Aug 30.
Article in English | MEDLINE | ID: mdl-22902501

ABSTRACT

Somatic cells can be reprogrammed into induced pluripotent stem cells (iPSCs) by using the pluripotency factors Oct4, Sox2, Klf4 and c-Myc (together referred to as OSKM). iPSC reprogramming erases somatic epigenetic signatures­as typified by DNA methylation or histone modification at silent pluripotency loci­and establishes alternative epigenetic marks of embryonic stem cells (ESCs). Here we describe an early and essential stage of somatic cell reprogramming, preceding the induction of transcription at endogenous pluripotency loci such as Nanog and Esrrb. By day 4 after transduction with OSKM, two epigenetic modification factors necessary for iPSC generation, namely poly(ADP-ribose) polymerase-1 (Parp1) and ten-eleven translocation-2 (Tet2), are recruited to the Nanog and Esrrb loci. These epigenetic modification factors seem to have complementary roles in the establishment of early epigenetic marks during somatic cell reprogramming: Parp1 functions in the regulation of 5-methylcytosine (5mC) modification, whereas Tet2 is essential for the early generation of 5-hydroxymethylcytosine (5hmC) by the oxidation of 5mC (refs 3,4). Although 5hmC has been proposed to serve primarily as an intermediate in 5mC demethylation to cytosine in certain contexts, our data, and also studies of Tet2-mutant human tumour cells, argue in favour of a role for 5hmC as an epigenetic mark distinct from 5mC. Consistent with this, Parp1 and Tet2 are each needed for the early establishment of histone modifications that typify an activated chromatin state at pluripotency loci, whereas Parp1 induction further promotes accessibility to the Oct4 reprogramming factor. These findings suggest that Parp1 and Tet2 contribute to an epigenetic program that directs subsequent transcriptional induction at pluripotency loci during somatic cell reprogramming.


Subject(s)
Cellular Reprogramming , DNA-Binding Proteins/metabolism , Epigenesis, Genetic , Induced Pluripotent Stem Cells/cytology , Induced Pluripotent Stem Cells/metabolism , Poly(ADP-ribose) Polymerases/metabolism , Proto-Oncogene Proteins/metabolism , Animals , Chromatin/genetics , Chromatin/metabolism , DNA Methylation , Dioxygenases , Exons/genetics , Fibroblasts/metabolism , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Humans , Introns/genetics , Kruppel-Like Factor 4 , Mice , Nanog Homeobox Protein , Poly (ADP-Ribose) Polymerase-1 , Poly(ADP-ribose) Polymerases/genetics , Receptors, Estrogen/genetics , Receptors, Estrogen/metabolism
7.
Cell ; 146(3): 359-71, 2011 Aug 05.
Article in English | MEDLINE | ID: mdl-21816272

ABSTRACT

Directed conversion of mature human cells, as from fibroblasts to neurons, is of potential clinical utility for neurological disease modeling as well as cell therapeutics. Here, we describe the efficient generation of human-induced neuronal (hiN) cells from adult skin fibroblasts of unaffected individuals and Alzheimer's patients, using virally transduced transcription regulators and extrinsic support factors. hiN cells from unaffected individuals display morphological, electrophysiological, and gene expression profiles that typify glutamatergic forebrain neurons and are competent to integrate functionally into the rodent CNS. hiN cells from familial Alzheimer disease (FAD) patients with presenilin-1 or -2 mutations exhibit altered processing and localization of amyloid precursor protein (APP) and increased production of Aß, relative to the source patient fibroblasts or hiN cells from unaffected individuals. Together, our findings demonstrate directed conversion of human fibroblasts to a neuronal phenotype and reveal cell type-selective pathology in hiN cells derived from FAD patients.


Subject(s)
Alzheimer Disease/pathology , Cell Transdifferentiation , Regenerative Medicine/methods , Skin/cytology , Alzheimer Disease/genetics , Amyloid beta-Protein Precursor/metabolism , Cells, Cultured , Fibroblasts/cytology , Humans , Neurons/metabolism , Presenilin-1/metabolism , Presenilin-2/metabolism
8.
J Neurochem ; 107(1): 152-60, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18680554

ABSTRACT

We examined the effects of lysophosphatidic acid (LPA) on microglia, which may play an important role in the development and maintenance of neuropathic pain. LPA caused membrane ruffling as detected by scanning electron microscopy, and increased the expression of brain-derived neurotrophic factor (BDNF) in a primary culture of rat microglia, which express LPA(3), but not LPA(1) or LPA(2) receptors. These actions were inhibited by a Galpha(q/11)-antisense oligodeoxynucleotide (AS-ODN), U73122, an inhibitor of phospholipase C (PLC), and apyrase, which specifically degrades ATP and ADP. When ATP release was measured using a luciferin-luciferase bioluminescence assay, LPA was shown to increase it in an LPA(3) and PLC inhibitor-reversible manner. However, LPA-induced ATP release was also blocked by the Galpha(q/11) AS-ODN, but not by pertussis toxin. These results suggest that LPA induces the release of ATP from rat primary cultured microglia via the LPA(3) receptor, Galpha(q/11) and PLC, and that the released ATP or ectopically converted ADP may in turn cause membrane ruffling via P2Y(12) receptors and Galpha(i/o) activation, and BDNF expression via activation of P2X(4) receptors.


Subject(s)
Adenosine Triphosphate/metabolism , Brain-Derived Neurotrophic Factor/genetics , Brain/metabolism , Cell Surface Extensions/metabolism , Lysophospholipids/pharmacology , Microglia/metabolism , Adenosine Diphosphate/metabolism , Animals , Brain/ultrastructure , Cell Surface Extensions/drug effects , Cell Surface Extensions/ultrastructure , Cells, Cultured , GTP-Binding Protein alpha Subunits, Gq-G11/antagonists & inhibitors , GTP-Binding Protein alpha Subunits, Gq-G11/genetics , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , Gene Expression Regulation/drug effects , Gene Expression Regulation/physiology , Microglia/drug effects , Microglia/ultrastructure , Microscopy, Electron, Scanning , RNA, Messenger/drug effects , RNA, Messenger/metabolism , Rats , Rats, Wistar , Receptors, Lysophosphatidic Acid/drug effects , Receptors, Lysophosphatidic Acid/metabolism , Receptors, Purinergic P2/drug effects , Receptors, Purinergic P2/metabolism , Receptors, Purinergic P2X4 , Type C Phospholipases/antagonists & inhibitors , Type C Phospholipases/metabolism
9.
J Cell Biol ; 176(6): 853-62, 2007 Mar 12.
Article in English | MEDLINE | ID: mdl-17353361

ABSTRACT

We initially identified a nuclear protein, prothymosin-alpha1 (ProTalpha), as a key protein inhibiting necrosis by subjecting conditioned media from serum-free cultures of cortical neurons to a few chromatography steps. ProTalpha inhibited necrosis of cultured neurons by preventing rapid loss of cellular adenosine triphosphate levels by reversing the decreased membrane localization of glucose transporters but caused apoptosis through up-regulation of proapoptotic Bcl(2)-family proteins. The apoptosis caused by ProTalpha was further inhibited by growth factors, including brain-derived neurotrophic factor. The ProTalpha-induced cell death mode switch from necrosis to apoptosis was also reproduced in experimental ischemia-reperfusion culture experiments, although the apoptosis level was markedly reduced, possibly because of the presence of growth factors in the reperfused serum. Knock down of PKCbeta(II) expression prevented this cell death mode switch. Collectively, these results suggest that ProTalpha is an extracellular signal protein that acts as a cell death mode switch and could be a promising candidate for preventing brain strokes with the help of known apoptosis inhibitors.


Subject(s)
Apoptosis , Cerebral Cortex/cytology , Necrosis , Neurons/cytology , Protein Precursors/physiology , Thymosin/analogs & derivatives , Amino Acid Sequence , Animals , Cells, Cultured , Culture Media, Conditioned , Molecular Sequence Data , Neurons/metabolism , Protein Precursors/genetics , Protein Precursors/isolation & purification , Rats , Thymosin/genetics , Thymosin/isolation & purification , Thymosin/physiology
10.
Neurochem Int ; 50(2): 351-5, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17056157

ABSTRACT

Lysophosphatidic acid (LPA) causes neuropathic pain with demyelination in sensory fibers. In dorsal root (DR) ex vivo culture, the addition of 0.1 microM LPA caused a characteristic demyelination at 24h in scanning and transmission electron microscopy analyses. Moreover, direct contact between C-fibers due to loss of partition by Schwann cell in Remak bundles was observed. LPA-induced demyelination of DR was concentration-dependent in the range between 0.01 and 1M, and was abolished by BoNT/C3 and Y-27632, a RhoA and Rho kinase inhibitor, respectively. The demyelination was equivalent between the preparations with and without dorsal root ganglion. LPA also caused a down-regulation of myelin proteins, such as myelin basic protein (MBP) and myelin protein zero (MPZ) to approximately 70% of control. All these findings suggest that the demyelination observed in the neuropathic pain due to nerve injury occurs through a direct action of LPA on Schwann cells.


Subject(s)
Demyelinating Diseases/pathology , Lysophospholipids/pharmacology , Myelin Sheath/drug effects , Spinal Nerve Roots/cytology , Animals , Blotting, Western , Cells, Cultured , Hyperalgesia/pathology , Male , Mice , Mice, Knockout , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Myelin Basic Protein/metabolism , Myelin P0 Protein/metabolism , Nerve Fibers/drug effects , Pain/physiopathology , Receptors, Lysophosphatidic Acid/drug effects , Receptors, Lysophosphatidic Acid/genetics , Receptors, Lysophosphatidic Acid/physiology , Schwann Cells/drug effects , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Tolonium Chloride
11.
Virus Res ; 112(1-2): 38-41, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16022899

ABSTRACT

We happened to discover that the cauliflower mosaic virus (CaMV) 35S promoter inserted into a recombinant Autographa californica multicapsid nucleopolyhedrovirus (rAcMNPV) was strongly activated during the replication of the recombinant virus in Spodoptera frugiperda (Sf9) cells. The expression of the luciferase gene from the 35S promoter in rAcMNPV was remarkably increased late in infection and was resistant to alpha-amanitin treatment. Primer extension indicated that transcriptional initiation from the 35S promoter in Sf9 cells occurred within one of the two baculoviral late promoter TAAG motifs located in the vicinity of the transcription start site in plant cells. These observations suggested that the CaMV 35S promoter served as a transcription start site for AcMNPV-induced RNA polymerase.


Subject(s)
Caulimovirus/genetics , Gene Expression Regulation, Viral , Nucleopolyhedroviruses/physiology , Promoter Regions, Genetic/physiology , Spodoptera/virology , Animals , Base Sequence , Cells, Cultured , DNA-Directed RNA Polymerases/genetics , DNA-Directed RNA Polymerases/metabolism , Luciferases/genetics , Luciferases/metabolism , Molecular Sequence Data , Nucleopolyhedroviruses/genetics , Promoter Regions, Genetic/genetics , Recombination, Genetic , Transcription, Genetic
12.
Br J Pharmacol ; 145(4): 545-50, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15821754

ABSTRACT

1 Agonistic neurosteroids, including pregnenolone, dehydroepiandrosterone and its sulfate (DHEAS), caused rapid degranulation in measurements of beta-hexosaminidase (beta-HEX) release from a mast cell line, RBL-2H3. This degranulation was blocked by BSA-conjugated progesterone (PROG-BSA) or 17beta-estradiol, both of which are antagonistic neurosteroids. 2 DHEAS-induced beta-HEX release was blocked by U-73122 or xestospongin C, but not by PTX or EGTA. DHEAS-induced beta-HEX release was also abolished by G(q/11)-AS, but not by G(q/11)-MS. Pharmacological analyses revealed that the neurosteroids stimulated a putative membrane receptor through activation of the novel G(q/11) and phospholipase C. 3 While representative endocrine-disrupting chemicals (EDCs) did not show any degranulation or nocifensive actions by themselves, they blocked the DHEAS-induced degranulation. 4 The binding of a PROG-BSA-fluorescein isothiocyanate conjugate (PROG-BSA-FITC) to cells was inhibited by neurosteroids and EDCs. 5 In the algogenic-induced biting and licking responses test, DHEAS caused agonistic nocifensive actions in a dose-dependent manner between 1 and 10 fmol (i.pl.). DHEAS-induced nocifensive actions were abolished by PROG-BSA or nonylphenol. 6 Taken together, these results suggest that a G(q/11)-coupled neurosteroid receptor may regulate the neuroimmunological activity related to sensory stimulation and that some EDCs have antagonistic actions for this receptor.


Subject(s)
GTP-Binding Protein alpha Subunits, Gi-Go/metabolism , Receptors, Steroid/metabolism , Animals , Behavior, Animal/drug effects , Binding, Competitive/drug effects , Cattle , Cell Line, Tumor , Cell Membrane/drug effects , Cell Membrane/metabolism , Dehydroepiandrosterone/pharmacology , Dehydroepiandrosterone Sulfate/pharmacology , Dose-Response Relationship, Drug , Estradiol/pharmacology , Estrenes/pharmacology , Fluorescein-5-isothiocyanate/chemistry , GTP-Binding Protein alpha Subunits, Gi-Go/genetics , Leukemia, Basophilic, Acute/metabolism , Leukemia, Basophilic, Acute/pathology , Macrocyclic Compounds , Male , Mast Cells/drug effects , Mast Cells/metabolism , Mast Cells/pathology , Mice , Nociceptors/drug effects , Oligonucleotides, Antisense/pharmacology , Oxazoles/pharmacology , Pain/chemically induced , Pain/prevention & control , Pertussis Toxin/pharmacology , Phenols/pharmacology , Phosphodiesterase Inhibitors/pharmacology , Pregnenolone/chemistry , Pregnenolone/metabolism , Pregnenolone/pharmacology , Pyrrolidinones/pharmacology , Serum Albumin, Bovine/chemistry , Type C Phospholipases/antagonists & inhibitors , Type C Phospholipases/metabolism , beta-N-Acetylhexosaminidases/metabolism
13.
J Pharmacol Exp Ther ; 313(3): 1027-34, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15705736

ABSTRACT

Ischemic stress causes neuronal death and functional impairment. Evidence has suggested that cells in the ischemic core first lose viability due to the decline in blood flow and cellular energy metabolism and then die by necrosis. Although inhibition of necrosis could be a potent therapeutic target for brain ischemia, known neurotrophic factors are ineffective for neuronal necrosis. We previously reported that insulin, but not brain-derived neurotrophic factor or insulin like-growth factor-1, inhibited neuronal necrosis under serum-free starvation stress. Although insulin receptors are abundant in the central nervous system as well as in peripheral tissues, neurons are not dependent upon insulin for their glucose supply, indicating that insulin receptors have other roles in the central nervous system. In the present study, by using hypoxia-reperfusion stress, we showed that cortical neurons rapidly died by necrosis as evaluated by propidium iodide staining and transmission electron microscopic analysis. As expected, insulin treatment significantly inhibited neuronal necrosis, although this effect was blocked by pretreatment with an antisense oligonucleotide for the insulin receptor. Furthermore, an inhibitor of protein kinase C (PKC) eliminated the insulin-induced antinecrotic effect. The addition of insulin induced significant translocation of only the PKC-gamma isoform, whereas antisense oligonucleotide treatment for this isoform abolished the insulin-induced inhibition of necrosis. Together, these results suggest that insulin mediates inhibition of neuronal necrosis through a novel mechanism involving PKC-gamma activation.


Subject(s)
Cell Hypoxia , Cerebral Cortex/pathology , Protein Kinase C/physiology , Receptor, Insulin/physiology , Signal Transduction/physiology , Animals , Cells, Cultured , Insulin/pharmacology , Necrosis , Protein Transport , Rats , Reperfusion
14.
Biol Pharm Bull ; 27(7): 950-5, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15256720

ABSTRACT

In brain ischemia, cell destructive necrosis occurs in the core, which in turn links to cell death expansion in the vicinity. Apoptosis, on the other hand, occurs in the surroundings of the core, called the penumbra, several days later. As cells showing apoptosis disappear by microglial phagocytosis in the brain, cell death induced by ischemic stress should eventually be terminated. Thus, the authors propose the hypothesis that the cell death mode switch in the event of brain ischemia is an in vivo self-protective mechanism. The authors attempt to overview the current understanding of the molecular mechanisms of necrosis and apoptosis in relation to the ATP hypothesis, and also introduce novel mechanisms for an in vitro cell death mode switch.


Subject(s)
Apoptosis/physiology , Brain/metabolism , Brain/pathology , Animals , Cell Death/physiology , Humans , Necrosis/metabolism , Necrosis/pathology
15.
Nat Med ; 10(7): 712-8, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15195086

ABSTRACT

Lysophosphatidic acid (LPA) is a bioactive lipid with activity in the nervous system mediated by G-protein-coupled receptors. Here, we examined the role of LPA signaling in the development of neuropathic pain by pharmacological and genetic approaches, including the use of mice lacking the LPA(1) receptor. Wild-type animals with nerve injury develop behavioral allodynia and hyperalgesia paralleled by demyelination in the dorsal root and increased expression of both the protein kinase C gamma-isoform within the spinal cord dorsal horn and the alpha(2)delta(1) calcium channel subunit in dorsal root ganglia. Intrathecal injection of LPA induced behavioral, morphological and biochemical changes similar to those observed after nerve ligation. In contrast, mice lacking a single LPA receptor (LPA(1), also known as EDG2) that activates the Rho-Rho kinase pathway do not develop signs of neuropathic pain after peripheral nerve injury. Inhibitors of Rho and Rho kinase also prevented these signs of neuropathic pain. These results imply that receptor-mediated LPA signaling is crucial in the initiation of neuropathic pain.


Subject(s)
Pain/etiology , Receptors, G-Protein-Coupled/physiology , Signal Transduction/physiology , ADP Ribose Transferases/pharmacology , Animals , Botulinum Toxins/pharmacology , Calcium Channels/physiology , Hyperalgesia/etiology , Male , Mice , Mice, Inbred C57BL , Protein Kinase C/physiology , Receptors, Lysophosphatidic Acid , rhoA GTP-Binding Protein/physiology
16.
J Pharmacol Exp Ther ; 309(1): 200-7, 2004 Apr.
Article in English | MEDLINE | ID: mdl-14718588

ABSTRACT

The retinal ischemic-reperfusion stress (130 mm Hg, 45 min) caused neuronal damage throughout all cell layers and reduced the thickness of retinal layer by 30% at 7 days after the stress of mouse retina. The intravitreous injection of 100 pmol of nefiracetam, a cognition-enhancer, completely prevented the damage when it was given 30 min before and 3 h after the stress. Partial prevention was observed when it was given 24 h after the stress, or low dose (10 pmol) nefiracetam was given 30 min before the stress. However, aniracetam had no effect. In the retinal cell line N18-RE-105, the ischemic-reperfusion stress by 2 h culture under the serum-free condition with low oxygen (less of 0.4% O(2)) and low glucose (1 mM) caused necrosis or apoptosis in the low-density (0.5 x 10(4) cell/cm(2))or high-density (5 x 10(4) cell/cm(2)) culture, respectively. The necrosis showed membrane disruption, loss of electron density, and mitochondrial swelling, whereas apoptosis showed nuclear fragmentation and condensation in transmission electron microscopical analyses and in experiments using specific cell death markers. Nefiracetam inhibited both necrosis and apoptosis, whereas brain-derived neurotrophic factor (BDNF) inhibited only apoptosis. The cell-protective actions of nefiracetam were abolished by nifedipine and omega-conotoxin GVIA, L-type and N-type calcium channel blocker, but not by PD98059 or wortmannin, extracellular signal-regulated kinase 1/2 or phosphoinositide 3-kinase inhibitor, respectively, whereas those of BDNF were abolished by PD98059 and wortmannin, but not by nifedipine and omega-conotoxin GVIA. All these findings suggest that nefiracetam inhibit necrosis and apoptosis occurred in the ischemic/hypoxic neuronal injury through an increase in Ca(2+) influx.


Subject(s)
Apoptosis , Cognition/drug effects , Eye Diseases/pathology , Hybridomas/drug effects , Ischemia/pathology , Pyrrolidinones/pharmacology , Retina/pathology , Animals , Brain-Derived Neurotrophic Factor/pharmacology , Brain-Derived Neurotrophic Factor/therapeutic use , Hybridomas/pathology , Mice , Necrosis , Neuroblastoma/pathology , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Pyrrolidinones/therapeutic use , Rats , Reperfusion Injury/prevention & control , Tumor Cells, Cultured
17.
J Pharmacol Exp Ther ; 307(1): 205-12, 2003 Oct.
Article in English | MEDLINE | ID: mdl-12808000

ABSTRACT

In the serum-free culture of rat embryonic neurons, most neurons rapidly died by necrosis, which was revealed by propidium iodide (PI)-positive staining as early as 3 h after the start of culture and by marked membrane disruption and mitochondrial swelling in transmission electron microscopic (TEM) analysis. However, neither nuclear condensation/fragmentation stained with Hoechst 33342 nor activated caspase-3-like immunoreactivity was observed. In the serum-deprived culture, on the other hand, neurons showed apoptotic features, such as caspase-3 activation and nuclear damages in TEM analysis. Insulin at relatively higher concentrations, up to 100 microg/ml, ameliorated the rapid decrease in survival activity measured with 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt WST-8 assay and PI staining in the serum-free culture, despite the fact that brain-derived neurotrophic factor and insulin-like growth factor-I had no survival effect even at concentrations up to 100 microg/ml. Insulin-induced survival effects were abolished by the protein kinase C (PKC) inhibitor calphostin C but not by the phosphatidyl inositol-3-OH-kinase inhibitor wortmannin or the mitogen-activated protein kinase inhibitors PD98059 or U0126. Insulin significantly stimulated the PKC activity in cell lysates and suppressed the mitochondrial swelling and membrane disruption in TEM analysis in a calphostin C-reversible manner. All of these findings suggest that insulin inhibited the neuronal necrosis resistant to known neurotrophic factors under the serum-free culture through PKC mechanisms.


Subject(s)
Insulin/pharmacology , Neurons/drug effects , Neuroprotective Agents/pharmacology , Protein Kinase C/metabolism , Protein Serine-Threonine Kinases , Adenosine Triphosphate/metabolism , Animals , Brain-Derived Neurotrophic Factor/pharmacology , Cerebral Cortex/cytology , Culture Media, Serum-Free , Enzyme Activation/drug effects , Glucose/metabolism , Microscopy, Electron , Mitogen-Activated Protein Kinases/metabolism , Necrosis , Neurons/pathology , Neurons/ultrastructure , Phosphorylation/drug effects , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-akt , Rats
18.
Neurochem Int ; 40(2): 139-43, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11738480

ABSTRACT

Cortical cells from embryonic mice (E17) showed a rapid cell-death under the serum-free condition. The addition of nefiracetam at 0.1-10 microM increased the survival activity, while aniracetam at the same concentrations did not. The cell death was characterized to be apoptotic, since dead cells showed nuclear condensation, fragmentation, and TUNEL-positive staining. The nefiracetam-induced anti-apoptotic activity was completely blocked by 1 microM nifedipine or omega-conotoxin GVIA, and partially by 1 microM verapamil. These results suggest that the reported anti-amnesic action of nefiracetam in ischemic animals may be partly attributed to the neuroprotective action.


Subject(s)
Apoptosis/drug effects , Brain-Derived Neurotrophic Factor/pharmacology , Cell Death/drug effects , Cell Survival/drug effects , Cerebral Cortex/cytology , Neurons/cytology , Nootropic Agents/pharmacology , Pyrrolidinones/pharmacology , Animals , Apoptosis/physiology , Cells, Cultured , Cerebral Cortex/embryology , Cognition/drug effects , Cognition/physiology , Culture Media, Serum-Free , Embryo, Mammalian , In Situ Nick-End Labeling , Mice , Mice, Inbred Strains , Neurons/drug effects , Verapamil/pharmacology , omega-Conotoxin GVIA/pharmacology , omega-Conotoxins/pharmacology
SELECTION OF CITATIONS
SEARCH DETAIL
...