1
|
Yan SD, Chen X, Fu J, Chen M, Zhu H, Roher A, Slattery T, Zhao L, Nagashima M, Morser J, Migheli A, Nawroth P, Stern D, Schmidt AM. RAGE and amyloid-beta peptide neurotoxicity in Alzheimer's disease. Nature 1996; 382:685-91. [PMID: 8751438 DOI: 10.1038/382685a0] [Citation(s) in RCA: 1533] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Amyloid-beta peptide is central to the pathology of Alzheimer's disease, because it is neurotoxic--directly by inducing oxidant stress, and indirectly by activating microglia. A specific cell-surface acceptor site that could focus its effects on target cells has been postulated but not identified. Here we present evidence that the 'receptor for advanced glycation end products' (RAGE) is such a receptor, and that it mediates effects of the peptide on neurons and microglia. Increased expressing of RAGE in Alzheimer's disease brain indicates that it is relevant to the pathogenesis of neuronal dysfunction and death.
Collapse
|
|
29 |
1533 |
2
|
Bargh JA, Chen M, Burrows L. Automaticity of social behavior: direct effects of trait construct and stereotype-activation on action. J Pers Soc Psychol 1996; 71:230-44. [PMID: 8765481 DOI: 10.1037/0022-3514.71.2.230] [Citation(s) in RCA: 1158] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Previous research has shown that trait concepts and stereotype become active automatically in the presence of relevant behavior or stereotyped-group features. Through the use of the same priming procedures as in previous impression formation research, Experiment 1 showed that participants whose concept of rudeness was printed interrupted the experimenter more quickly and frequently than did participants primed with polite-related stimuli. In Experiment 2, participants for whom an elderly stereotype was primed walked more slowly down the hallway when leaving the experiment than did control participants, consistent with the content of that stereotype. In Experiment 3, participants for whom the African American stereotype was primed subliminally reacted with more hostility to a vexatious request of the experimenter. Implications of this automatic behavior priming effect for self-fulfilling prophecies are discussed, as is whether social behavior is necessarily mediated by conscious choice processes.
Collapse
|
|
29 |
1158 |
3
|
Cybulsky MI, Iiyama K, Li H, Zhu S, Chen M, Iiyama M, Davis V, Gutierrez-Ramos JC, Connelly PW, Milstone DS. A major role for VCAM-1, but not ICAM-1, in early atherosclerosis. J Clin Invest 2001; 107:1255-62. [PMID: 11375415 PMCID: PMC209298 DOI: 10.1172/jci11871] [Citation(s) in RCA: 879] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
VCAM-1 and ICAM-1 are endothelial adhesion molecules of the Ig gene superfamily that may participate in atherogenesis by promoting monocyte accumulation in the arterial intima. Both are expressed in regions predisposed to atherosclerosis and at the periphery of established lesions, while ICAM-1 is also expressed more broadly. To evaluate functions of VCAM-1 in chronic disease, we disrupted its fourth Ig domain, producing the murine Vcam1(D4D) allele. VCAM-1(D4D) mRNA and protein were reduced to 2-8% of wild-type allele (Vcam1(+)) levels but were sufficient to partially rescue the lethal phenotype of VCAM-1-null embryos. After crossing into the LDL receptor-null background, Vcam1(+/+) and Vcam1(D4D/D4D) paired littermates were generated from heterozygous intercrosses and fed a cholesterol-enriched diet for 8 weeks. The area of early atherosclerotic lesions in the aorta, quantified by en face oil red O staining, was reduced significantly in Vcam1(D4D/D4D) mice, although cholesterol levels, lipoprotein profiles, and numbers of circulating leukocytes were comparable to wild-type. In contrast, deficiency of ICAM-1 either alone or in combination with VCAM-1 deficiency did not alter nascent lesion formation. Therefore, although expression of both VCAM-1 and ICAM-1 is upregulated in atherosclerotic lesions, our data indicate that VCAM-1 plays a dominant role in the initiation of atherosclerosis.
Collapse
|
Research Support, U.S. Gov't, P.H.S. |
24 |
879 |
4
|
Martin KC, Casadio A, Zhu H, Yaping E, Rose JC, Chen M, Bailey CH, Kandel ER. Synapse-specific, long-term facilitation of aplysia sensory to motor synapses: a function for local protein synthesis in memory storage. Cell 1997; 91:927-38. [PMID: 9428516 DOI: 10.1016/s0092-8674(00)80484-5] [Citation(s) in RCA: 554] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The requirement for transcription during long-lasting synaptic plasticity has raised the question of whether the cellular unit of synaptic plasticity is the soma and its nucleus or the synapse. To address this question, we cultured a single bifurcated Aplysia sensory neuron making synapses with two spatially separated motor neurons. By perfusing serotonin onto the synapses made onto one motor neuron, we found that a single axonal branch can undergo long-term branch-specific facilitation. This branch-specific facilitation depends on CREB-mediated transcription and involves the growth of new synaptic connections exclusively at the treated branch. Branch-specific long-term facilitation requires local protein synthesis in the presynaptic but not the postsynaptic cell. In fact, presynaptic sensory neuron axons deprived of their cell bodies are capable of protein synthesis, and this protein synthesis is stimulated 3-fold by exposure to serotonin.
Collapse
|
|
28 |
554 |
5
|
Winder WW, Holmes BF, Rubink DS, Jensen EB, Chen M, Holloszy JO. Activation of AMP-activated protein kinase increases mitochondrial enzymes in skeletal muscle. J Appl Physiol (1985) 2000; 88:2219-26. [PMID: 10846039 DOI: 10.1152/jappl.2000.88.6.2219] [Citation(s) in RCA: 530] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Muscle contraction causes an increase in activity of 5'-AMP-activated protein kinase (AMPK). This study was designed to determine whether chronic chemical activation of AMPK will increase mitochondrial enzymes, GLUT-4, and hexokinase in different types of skeletal muscle of resting rats. In acute studies, rats were subcutaneously injected with either 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR; 1 mg/g body wt) in 0.9% NaCl or with 0.9% NaCl alone and were then anesthetized for collection and freezing of tissues. AMPK activity increased in the superficial, white region of the quadriceps and in soleus muscles but not in the deep, red region of the quadriceps muscle. Acetyl-CoA carboxylase (ACC) activity, a target for AMPK, decreased in all three muscle types in response to AICAR injection but was lowest in the white quadriceps. In rats given daily, 1 mg/g body wt, subcutaneous injections of AICAR for 4 wk, activities of citrate synthase, succinate dehydrogenase, and malate dehydrogenase were increased in white quadriceps and soleus but not in red quadriceps. Cytochrome c and delta-aminolevulinic acid synthase levels were increased in white, but not red, quadriceps. Carnitine palmitoyl-transferase and hydroxy-acyl-CoA dehydrogenase were not significantly increased. Hexokinase was markedly increased in all three muscles, and GLUT-4 was increased in red and white quadriceps. These results suggest that chronic AMPK activation may mediate the effects of muscle contraction on some, but not all, biochemical adaptations of muscle to endurance exercise training.
Collapse
|
|
25 |
530 |
6
|
Li M, Ona VO, Guégan C, Chen M, Jackson-Lewis V, Andrews LJ, Olszewski AJ, Stieg PE, Lee JP, Przedborski S, Friedlander RM. Functional role of caspase-1 and caspase-3 in an ALS transgenic mouse model. Science 2000; 288:335-9. [PMID: 10764647 DOI: 10.1126/science.288.5464.335] [Citation(s) in RCA: 523] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Mutations in the copper/zinc superoxide dismutase (SOD1) gene produce an animal model of familial amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. To test a new therapeutic strategy for ALS, we examined the effect of caspase inhibition in transgenic mice expressing mutant human SOD1 with a substitution of glycine to alanine in position 93 (mSOD1(G93A)). Intracerebroventricular administration of zVAD-fmk, a broad caspase inhibitor, delays disease onset and mortality. Moreover, zVAD-fmk inhibits caspase-1 activity as well as caspase-1 and caspase-3 mRNA up-regulation, providing evidence for a non-cell-autonomous pathway regulating caspase expression. Caspases play an instrumental role in neurodegeneration in transgenic mSOD1(G93A) mice, which suggests that caspase inhibition may have a protective role in ALS.
Collapse
|
|
25 |
523 |
7
|
Chen M, Ona VO, Li M, Ferrante RJ, Fink KB, Zhu S, Bian J, Guo L, Farrell LA, Hersch SM, Hobbs W, Vonsattel JP, Cha JH, Friedlander RM. Minocycline inhibits caspase-1 and caspase-3 expression and delays mortality in a transgenic mouse model of Huntington disease. Nat Med 2000; 6:797-801. [PMID: 10888929 DOI: 10.1038/77528] [Citation(s) in RCA: 499] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Huntington disease is an autosomal dominant neurodegenerative disease with no effective treatment. Minocycline is a tetracycline derivative with proven safety. After ischemia, minocycline inhibits caspase-1 and inducible nitric oxide synthetase upregulation, and reduces infarction. As caspase-1 and nitric oxide seem to play a role in Huntington disease, we evaluated the therapeutic efficacy of minocycline in the R6/2 mouse model of Huntington disease. We report that minocycline delays disease progression, inhibits caspase-1 and caspase-3 mRNA upregulation, and decreases inducible nitric oxide synthetase activity. In addition, effective pharmacotherapy in R6/2 mice requires caspase-1 and caspase-3 inhibition. This is the first demonstration of caspase-1 and caspase-3 transcriptional regulation in a Huntington disease model.
Collapse
|
|
25 |
499 |
8
|
Bartsch D, Ghirardi M, Skehel PA, Karl KA, Herder SP, Chen M, Bailey CH, Kandel ER. Aplysia CREB2 represses long-term facilitation: relief of repression converts transient facilitation into long-term functional and structural change. Cell 1995; 83:979-92. [PMID: 8521521 DOI: 10.1016/0092-8674(95)90213-9] [Citation(s) in RCA: 431] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The switch from short- to long-term facilitation induced by behavioral sensitization in Aplysia involves CREB-like proteins, as well as the immediate-early gene ApC/EBP. Using the bZIP domain of ApC/EBP in a two-hybrid system, we have cloned ApCREB2, a transcription factor constitutively expressed in sensory neurons that resembles human CREB2 and mouse ATF4. ApCREB2 represses ApCREB1-mediated transcription in F9 cells. Injection of anti-ApCREB2 antibodies into Aplysia sensory neurons causes a single pulse of serotonin (5-HT), which induces only short-term facilitation lasting minutes, to evoke facilitation lasting more than 1 day. This facilitation has the properties of long-term facilitation: it requires transcription and translation, induces the growth of new synaptic connections, and occludes further facilitation by five pulses of 5-HT.
Collapse
|
|
30 |
431 |
9
|
Hajra L, Evans AI, Chen M, Hyduk SJ, Collins T, Cybulsky MI. The NF-kappa B signal transduction pathway in aortic endothelial cells is primed for activation in regions predisposed to atherosclerotic lesion formation. Proc Natl Acad Sci U S A 2000; 97:9052-7. [PMID: 10922059 PMCID: PMC16820 DOI: 10.1073/pnas.97.16.9052] [Citation(s) in RCA: 422] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Atherosclerotic lesions form at distinct sites in the arterial tree, suggesting that hemodynamic forces influence the initiation of atherogenesis. If NF-kappaB plays a role in atherogenesis, then the activation of this signal transduction pathway in arterial endothelium should show topographic variation. The expression of NF-kappaB/IkappaB components and NF-kappaB activation was evaluated by specific antibody staining, en face confocal microscopy, and image analysis of endothelium in regions of mouse proximal aorta with high and low probability (HP and LP) for atherosclerotic lesion development. In control C57BL/6 mice, expression levels of p65, IkappaBalpha, and IkappaBbeta were 5- to 18-fold higher in the HP region, yet NF-kappaB was activated in a minority of endothelial cells. This suggested that NF-kappaB signal transduction was primed for activation in HP regions on encountering an activation stimulus. Lipopolysaccharide treatment or feeding low-density lipoprotein receptor knockout mice an atherogenic diet resulted in NF-kappaB activation and up-regulated expression of NF-kappaB-inducible genes predominantly in HP region endothelium. Preferential regional activation of endothelial NF-kappaB by systemic stimuli, including hypercholesterolemia, may contribute to the localization of atherosclerotic lesions at sites with high steady-state expression levels of NF-kappaB/IkappaB components.
Collapse
|
research-article |
25 |
422 |
10
|
Widera G, Austin M, Rabussay D, Goldbeck C, Barnett SW, Chen M, Leung L, Otten GR, Thudium K, Selby MJ, Ulmer JB. Increased DNA vaccine delivery and immunogenicity by electroporation in vivo. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:4635-40. [PMID: 10779767 DOI: 10.4049/jimmunol.164.9.4635] [Citation(s) in RCA: 404] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
DNA vaccines have been demonstrated to be potent in small animals but are less effective in primates. One limiting factor may be inefficient uptake of DNA by cells in situ. In this study, we evaluated whether cellular uptake of DNA was a significant barrier to efficient transfection in vivo and subsequent induction of immune responses. For this purpose, we used the technique of electroporation to facilitate DNA delivery in vivo. This technology was shown to substantially increase delivery of DNA to cells, resulting in increased expression and elevated immune responses. The potency of a weakly immunogenic hepatitis B surface Ag DNA vaccine was increased in mice, as seen by a more rapid onset and higher magnitude of anti-hepatitis B Abs. In addition, the immunogenicity of a potent HIV gag DNA vaccine was increased in mice, as seen by higher Ab titers, a substantial reduction in the dose of DNA required to induce an Ab response, and an increase in CD8+ T cell responses. Finally, Ab responses were enhanced by electroporation against both components of a combination HIV gag and env DNA vaccine in guinea pigs and rabbits. Therefore, cellular uptake of DNA is a significant barrier to transfection in vivo, and electroporation appears able to overcome this barrier.
Collapse
MESH Headings
- AIDS Vaccines/administration & dosage
- AIDS Vaccines/genetics
- AIDS Vaccines/immunology
- Animals
- Dose-Response Relationship, Immunologic
- Electroporation
- Female
- Gene Products, env/genetics
- Gene Products, env/immunology
- Gene Products, gag/genetics
- Gene Products, gag/immunology
- Guinea Pigs
- HIV Antibodies/biosynthesis
- HIV-1/genetics
- HIV-1/immunology
- Hepatitis B Antibodies/biosynthesis
- Hepatitis B Surface Antigens/genetics
- Hepatitis B Surface Antigens/immunology
- Hepatitis B Vaccines/administration & dosage
- Hepatitis B Vaccines/genetics
- Hepatitis B Vaccines/immunology
- Injections, Intramuscular
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Nude
- Rabbits
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/genetics
- Vaccines, DNA/immunology
Collapse
|
|
25 |
404 |
11
|
Samuelson JC, Chen M, Jiang F, Möller I, Wiedmann M, Kuhn A, Phillips GJ, Dalbey RE. YidC mediates membrane protein insertion in bacteria. Nature 2000; 406:637-41. [PMID: 10949305 DOI: 10.1038/35020586] [Citation(s) in RCA: 398] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The basic machinery for the translocation of proteins into or across membranes is remarkably conserved from Escherichia coli to humans. In eukaryotes, proteins are inserted into the endoplasmic reticulum using the signal recognition particle (SRP) and the SRP receptor, as well as the integral membrane Sec61 trimeric complex (composed of alpha, beta and gamma subunits). In bacteria, most proteins are inserted by a related pathway that includes the SRP homologue Ffh, the SRP receptor FtsY, and the SecYEG trimeric complex, where Y and E are related to the Sec61 alpha and gamma subunits, respectively. Proteins in bacteria that exhibit no dependence on the Sec translocase were previously thought to insert into the membrane directly without the aid of a protein machinery. Here we show that membrane insertion of two Sec-independent proteins requires YidC. YidC is essential for E. coli viability and homologues are present in mitochondria and chloroplasts. Depletion of YidC also interferes with insertion of Sec-dependent membrane proteins, but it has only a minor effect on the export of secretory proteins. These results provide evidence for an additional component of the translocation machinery that is specialized for the integration of membrane proteins.
Collapse
|
|
25 |
398 |
12
|
Casadio A, Martin KC, Giustetto M, Zhu H, Chen M, Bartsch D, Bailey CH, Kandel ER. A transient, neuron-wide form of CREB-mediated long-term facilitation can be stabilized at specific synapses by local protein synthesis. Cell 1999; 99:221-37. [PMID: 10535740 DOI: 10.1016/s0092-8674(00)81653-0] [Citation(s) in RCA: 386] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In a culture system where a bifurcated Aplysia sensory neuron makes synapses with two motor neurons, repeated application of serotonin (5-HT) to one synapse produces a CREB-mediated, synapse-specific, long-term facilitation, which can be captured at the opposite synapse by a single pulse of 5-HT. Repeated pulses of 5-HT applied to the cell body of the sensory neuron produce a CREB-dependent, cell-wide facilitation, which, unlike synapse-specific facilitation, is not associated with growth and does not persist beyond 48 hr. Persistent facilitation and synapse-specific growth can be induced by a single pulse of 5-HT applied to a peripheral synapse. Thus, the short-term process initiated by a single pulse of 5-HT serves not only to produce transient facilitation, but also to mark and stabilize any synapse of the neuron for long-term facilitation by means of a covalent mark and rapamycin-sensitive local protein synthesis.
Collapse
|
|
26 |
386 |
13
|
Buckwold VE, Xu Z, Chen M, Yen TS, Ou JH. Effects of a naturally occurring mutation in the hepatitis B virus basal core promoter on precore gene expression and viral replication. J Virol 1996; 70:5845-51. [PMID: 8709203 PMCID: PMC190601 DOI: 10.1128/jvi.70.9.5845-5851.1996] [Citation(s) in RCA: 371] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The basal core promoter (BCP) of hepatitis B virus (HBV) controls the transcription of both the precore RNA and the core RNA. The precore RNA codes for the secreted e antigen, while the core RNA codes for the major core protein and the DNA polymerase and also is the pregenomic RNA. The double mutation of nucleotides 1762 and 1764 in the BCP from A and G to T and A, respectively, is frequently observed in HBV sequences isolated from chronic patients. Several papers have reported conflicting results regarding whether this double mutation is important for e antigen expression. In order to address this issue, we have introduced this double mutation into the HBV genome and studied its effects on HBV gene expression and replication. Our results indicate that the mutated BCP can no longer bind a liver-enriched transcription factor(s) and that the transcription of only precore RNA and, consequently, the expression of e antigen were reduced. The reduction of precore gene expression was accompanied by an increase in progeny virus production. This increase was found to occur at or immediately prior to the encapsidation of the pregenomic RNA. Thus, the results of our in vitro study resolve the discrepancy of previous clinical observations and indicate that this double mutation suppresses but does not abolish the e antigen phenotype. The implications of these findings in the pathogenesis of HBV are discussed.
Collapse
|
research-article |
29 |
371 |
14
|
Eisenberg I, Avidan N, Potikha T, Hochner H, Chen M, Olender T, Barash M, Shemesh M, Sadeh M, Grabov-Nardini G, Shmilevich I, Friedmann A, Karpati G, Bradley WG, Baumbach L, Lancet D, Asher EB, Beckmann JS, Argov Z, Mitrani-Rosenbaum S. The UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase gene is mutated in recessive hereditary inclusion body myopathy. Nat Genet 2001; 29:83-7. [PMID: 11528398 DOI: 10.1038/ng718] [Citation(s) in RCA: 363] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Hereditary inclusion body myopathy (HIBM; OMIM 600737) is a unique group of neuromuscular disorders characterized by adult onset, slowly progressive distal and proximal weakness and a typical muscle pathology including rimmed vacuoles and filamentous inclusions. The autosomal recessive form described in Jews of Persian descent is the HIBM prototype. This myopathy affects mainly leg muscles, but with an unusual distribution that spares the quadriceps. This particular pattern of weakness distribution, termed quadriceps-sparing myopathy (QSM), was later found in Jews originating from other Middle Eastern countries as well as in non-Jews. We previously localized the gene causing HIBM in Middle Eastern Jews on chromosome 9p12-13 (ref. 5) within a genomic interval of about 700 kb (ref. 6). Haplotype analysis around the HIBM gene region of 104 affected people from 47 Middle Eastern families indicates one unique ancestral founder chromosome in this community. By contrast, single non-Jewish families from India, Georgia (USA) and the Bahamas, with QSM and linkage to the same 9p12-13 region, show three distinct haplotypes. After excluding other potential candidate genes, we eventually identified mutations in the UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE) gene in the HIBM families: all patients from Middle Eastern descent shared a single homozygous missense mutation, whereas distinct compound heterozygotes were identified in affected individuals of families of other ethnic origins. Our findings indicate that GNE is the gene responsible for recessive HIBM.
Collapse
|
|
24 |
363 |
15
|
Baranes D, Lederfein D, Huang YY, Chen M, Bailey CH, Kandel ER. Tissue plasminogen activator contributes to the late phase of LTP and to synaptic growth in the hippocampal mossy fiber pathway. Neuron 1998; 21:813-25. [PMID: 9808467 DOI: 10.1016/s0896-6273(00)80597-8] [Citation(s) in RCA: 352] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The expression of tissue plasminogen activator (tPA) is increased during activity-dependent forms of synaptic plasticity. We have found that inhibitors of tPA inhibit the late phase of long-term potentiation (L-LTP) induced by either forskolin or tetanic stimulation in the hippocampal mossy fiber and Schaffer collateral pathways. Moreover, application of tPA enhances L-LTP induced by a single tetanus. Exposure of granule cells in culture to forskolin results in secretion of tPA, elongation of mossy fiber axons, and formation of new, active presynaptic varicosities contiguous to dendritic clusters of the glutamate receptor R1. These structural changes are blocked by tPA inhibitors and induced by application of tPA. Thus, tPA may be critically involved in the production of L-LTP and specifically in synaptic growth.
Collapse
|
|
27 |
352 |
16
|
|
Comparative Study |
43 |
350 |
17
|
Abstract
Death receptor- or mitochondrion-dependent apoptosis is initiated by the recruitment and activation of apical caspases in the apoptosis signaling pathways. In death receptor-mediated apoptosis, engagement of death receptors leads to the formation of the death-inducing signaling complex (DISC) containing the death receptors, adaptor proteins, caspase-8 and caspase-10. In mitochondrion-dependent apoptosis, release of cytochrome C into the cytosol results in the formation of apoptosome containing cytochrome C, Apaf-1 and caspase-9. Caspase-8, caspase-10 and caspase-9 are believed to be the initiator caspases at the top of the caspase signaling cascade. Recruitment of caspases to DISC and apoptosome leads to their activation by dimer formation. Recent biochemical and structural analyses of components in the DISC and apoptosome shed new lights on their roles in inducing the onset of apoptosis signaling.
Collapse
|
Review |
23 |
342 |
18
|
Juan LJ, Shia WJ, Chen MH, Yang WM, Seto E, Lin YS, Wu CW. Histone deacetylases specifically down-regulate p53-dependent gene activation. J Biol Chem 2000; 275:20436-43. [PMID: 10777477 DOI: 10.1074/jbc.m000202200] [Citation(s) in RCA: 333] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
p53, the most commonly mutated gene in cancer cells, directs cell cycle arrest or induces programmed cell death (apoptosis) in response to stress. It has been demonstrated that p53 activity is up-regulated in part by posttranslational acetylation. In agreement with these observations, here we show that mammalian histone deacetylase (HDAC)-1, -2, and -3 are all capable of down-regulating p53 function. Down-regulation of p53 activity by HDACs is HDAC dosage-dependent, requires the deacetylase activity of HDACs, and depends on the region of p53 that is acetylated by p300/CREB-binding protein (CBP). These results suggest that interactions of p53 and HDACs likely result in p53 deacetylation, thereby reducing its transcriptional activity. In support of this idea, GST pull-down and immunoprecipitation assays show that p53 interacts with HDAC1 both in vitro and in vivo. Furthermore, a pre-acetylated p53 peptide was significantly deacetylated by immunoprecipitated wild type HDAC1 but not deacetylase mutant. Also, co-expression of HDAC1 greatly reduced the in vivo acetylation level of p53. Finally, we report that the activation potential of p53 on the BAX promoter, a natural p53-responsive system, is reduced in the presence of HDACs. Taken together, our findings indicate that deacetylation of p53 by histone deacetylases is likely to be part of the mechanisms that control the physiological activity of p53.
Collapse
|
|
25 |
333 |
19
|
Onishi HR, Pelak BA, Gerckens LS, Silver LL, Kahan FM, Chen MH, Patchett AA, Galloway SM, Hyland SA, Anderson MS, Raetz CR. Antibacterial agents that inhibit lipid A biosynthesis. Science 1996; 274:980-2. [PMID: 8875939 DOI: 10.1126/science.274.5289.980] [Citation(s) in RCA: 330] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Lipid A constitutes the outer monolayer of the outer membrane of Gram-negative bacteria and is essential for bacterial growth. Synthetic antibacterials were identified that inhibit the second enzyme (a unique deacetylase) of lipid A biosynthesis. The inhibitors are chiral hydroxamic acids bearing certain hydrophobic aromatic moieties. They may bind to a metal in the active site of the deacetylase. The most potent analog (with an inhibition constant of about 50 nM) displayed a minimal inhibitory concentration of about 1 microgram per milliliter against Escherichia coli, caused three logs of bacterial killing in 4 hours, and cured mice infected with a lethal intraperitoneal dose of E. coli.
Collapse
|
|
29 |
330 |
20
|
Wu T, Gao X, Chen M, van Dam RM. Long-term effectiveness of diet-plus-exercise interventions vs. diet-only interventions for weight loss: a meta-analysis. Obes Rev 2009; 10:313-23. [PMID: 19175510 DOI: 10.1111/j.1467-789x.2008.00547.x] [Citation(s) in RCA: 312] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Diet and exercise are two of the commonest strategies to reduce weight. Whether a diet-plus-exercise intervention is more effective for weight loss than a diet-only intervention in the long-term has not been conclusively established. The objective of this study was to systemically review the effect of diet-plus-exercise interventions vs. diet-only interventions on both long-term and short-term weight loss. Studies were retrieved by searching MEDLINE and Cochrane Library (1966 - June 2008). Studies were included if they were randomized controlled trials comparing the effect of diet-plus-exercise interventions vs. diet-only interventions on weight loss for a minimum of 6 months among obese or overweight adults. Eighteen studies met our inclusion criteria. Data were independently extracted by two investigators using a standardized protocol. We found that the overall standardized mean differences between diet-plus-exercise interventions and diet-only interventions at the end of follow-up were -0.25 (95% confidence interval [CI]-0.36 to -0.14), with a P-value for heterogeneity of 0.4. Because there were two outcome measurements, weight (kg) and body mass index (kg m(-2)), we also stratified the results by weight and body mass index outcome. The pooled weight loss was 1.14 kg (95% CI 0.21 to 2.07) or 0.50 kg m(-2) (95% CI 0.21 to 0.79) greater for the diet-plus-exercise group than the diet-only group. We did not detect significant heterogeneity in either stratum. Even in studies lasting 2 years or longer, diet-plus-exercise interventions provided significantly greater weight loss than diet-only interventions. In summary, a combined diet-plus-exercise programme provided greater long-term weight loss than a diet-only programme. However, both diet-only and diet-plus-exercise programmes are associated with partial weight regain, and future studies should explore better strategies to limit weight regain and achieve greater long-term weight loss.
Collapse
|
Meta-Analysis |
16 |
312 |
21
|
Satin J, Kyle JW, Chen M, Bell P, Cribbs LL, Fozzard HA, Rogart RB. A mutant of TTX-resistant cardiac sodium channels with TTX-sensitive properties. Science 1992; 256:1202-5. [PMID: 1375397 DOI: 10.1126/science.256.5060.1202] [Citation(s) in RCA: 310] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The cardiac sodium channel alpha subunit (RHI) is less sensitive to tetrodotoxin (TTX) and saxitoxin (STX) and more sensitive to cadmium than brain and skeletal muscle (microliter) isoforms. An RHI mutant, with Tyr substituted for Cys at position 374 (as in microliter) confers three properties of TTX-sensitive channels: (i) greater sensitivity to TTX (730-fold); (ii) lower sensitivity to cadmium (28-fold); and (iii) altered additional block by toxin upon repetitive stimulation. Thus, the primary determinant of high-affinity TTX-STX binding is a critical aromatic residue at position 374, and the interaction may take place possibly through an ionized hydrogen bond. This finding requires revision of the sodium channel pore structure that has been previously suggested by homology with the potassium channel.
Collapse
|
Comparative Study |
33 |
310 |
22
|
Clark RS, Kochanek PM, Watkins SC, Chen M, Dixon CE, Seidberg NA, Melick J, Loeffert JE, Nathaniel PD, Jin KL, Graham SH. Caspase-3 mediated neuronal death after traumatic brain injury in rats. J Neurochem 2000; 74:740-53. [PMID: 10646526 DOI: 10.1046/j.1471-4159.2000.740740.x] [Citation(s) in RCA: 309] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During programmed cell death, activation of caspase-3 leads to proteolysis of DNA repair proteins, cytoskeletal proteins, and the inhibitor of caspase-activated deoxyribonuclease, culminating in morphologic changes and DNA damage defining apoptosis. The participation of caspase-3 activation in the evolution of neuronal death after traumatic brain injury in rats was examined. Cleavage of pro-caspase-3 in cytosolic cellular fractions and an increase in caspase-3-like enzyme activity were seen in injured brain versus control. Cleavage of the caspase-3 substrates DNA-dependent protein kinase and inhibitor of caspase-activated deoxyribonuclease and co-localization of cytosolic caspase-3 in neurons with evidence of DNA fragmentation were also identified. Intracerebral administration of the caspase-3 inhibitor N-benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethyl ketone (480 ng) after trauma reduced caspase-3-like activity and DNA fragmentation in injured brain versus vehicle at 24 h. Treatment with N-benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethyl ketone for 72 h (480 ng/day) reduced contusion size and ipsilateral dorsal hippocampal tissue loss at 3 weeks but had no effect on functional outcome versus vehicle. These data demonstrate that caspase-3 activation contributes to brain tissue loss and downstream biochemical events that execute programmed cell death after traumatic brain injury. Caspase inhibition may prove efficacious in the treatment of certain types of brain injury where programmed cell death occurs.
Collapse
|
|
25 |
309 |
23
|
Lo GH, Lai KH, Cheng JS, Chen MH, Chiang HT. A prospective, randomized trial of butyl cyanoacrylate injection versus band ligation in the management of bleeding gastric varices. Hepatology 2001; 33:1060-4. [PMID: 11343232 DOI: 10.1053/jhep.2001.24116] [Citation(s) in RCA: 302] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Gastric variceal bleeding is a catastrophic event. Both cyanoacrylate injection and banding ligation have been proven to be effective in the management of bleeding gastric varices. This study was performed to compare the efficacy and complications of both the modalities. Cirrhotic patients with a history of gastric variceal bleeding were randomized to 2 groups. The group receiving endoscopic obturation (group A) comprised 31 patients and the group receiving band ligation (group B) comprised 29 patients. Butyl cyanoacrylate and pneumatic-driven ligator were applied, respectively. Treatment was repeated regularly until obliteration of gastric varices. Active bleeding occurred in 15 patients in group A and 11 patients in group B. Initial hemostatic rate (defined as no bleeding for 72 hours after treatment) was 87% in group A and 45% in group B (P = .03). The sessions required to achieve variceal obliteration and obliteration rates were similar in both the groups. However, rebleeding rates were significantly higher in group B (54%) than group A (31%) (P = .0005). Treatment-induced ulcer bleeding occurred in 2 patients (7%) in group A and 8 patients (28%) in group B (P = .03). The amount of blood transfusions required were also higher in group B than group A (4.2 +/- 1.3 vs. 2.6 +/- 0.9 units, respectively) (P < .01). Nine patients of group A and 14 patients of group B died (P = .05). In conclusion, endoscopic obturation using cyanoacrylate proved more effective and safer than band ligation in the management of bleeding gastric varices.
Collapse
|
Clinical Trial |
24 |
302 |
24
|
Si L, Winzenberg TM, Jiang Q, Chen M, Palmer AJ. Projection of osteoporosis-related fractures and costs in China: 2010-2050. Osteoporos Int 2015; 26:1929-37. [PMID: 25761729 DOI: 10.1007/s00198-015-3093-2] [Citation(s) in RCA: 301] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/27/2015] [Indexed: 10/23/2022]
Abstract
UNLABELLED A state-transition microsimulation model was used to project the substantial economic burden to the Chinese healthcare system of osteoporosis-related fractures. Annual number and costs of osteoporosis-related fractures were estimated to double by 2035 and will increase to 5.99 (95 % CI 5.44, 6.55) million fractures costing $25.43 (95 % CI 23.92, 26.95) billion by 2050. Consequently, cost-effective intervention policies must urgently be identified in an attempt to minimize the impact of fractures. INTRODUCTION The aim of the study was to project the osteoporosis-related fractures and costs for the Chinese population aged ≥50 years from 2010 to 2050. METHODS A state-transition microsimulation model was used to simulate the annual incident fractures and costs. The simulation was performed with a 1-year cycle length and from the Chinese healthcare system perspective. Incident fractures and annual costs were estimated from 100 unique patient populations for year 2010, by multiplying the age- and sex-specific annual fracture risks and costs of fracture by the corresponding population totals in each of the 100 categories. Projections for 2011-2050 were performed by multiplying the 2010 risks and costs of fracture by the respective annual population estimates. Costs were presented in 2013 US dollars. RESULTS Approximately 2.33 (95 % CI 2.08, 2.58) million osteoporotic fractures were estimated to occur in 2010, costing $9.45 (95 % CI 8.78, 10.11) billion. Females sustained approximately three times more fractures than males, accounting for 76 % of the total costs from 1.85 (95 % CI 1.68, 2.01) million fractures. The annual number and costs of osteoporosis-related fractures were estimated to double by 2035 and will increase to 5.99 (95 % CI 5.44, 6.55) million fractures costing $25.43 (95 % CI 23.92, 26.95) billion by 2050. CONCLUSIONS Our study demonstrated that osteoporosis-related fractures cause a substantial economic burden which will markedly increase over the coming decades. Consequently, healthcare resource planning must consider these increasing costs, and cost-effective screening and intervention policies must urgently be identified in an attempt to minimize the impact of fractures on the health of the burgeoning population as well as the healthcare budget.
Collapse
|
|
10 |
301 |
25
|
D'Amico AV, Whittington R, Malkowicz SB, Fondurulia J, Chen MH, Kaplan I, Beard CJ, Tomaszewski JE, Renshaw AA, Wein A, Coleman CN. Pretreatment nomogram for prostate-specific antigen recurrence after radical prostatectomy or external-beam radiation therapy for clinically localized prostate cancer. J Clin Oncol 1999; 17:168-72. [PMID: 10458230 DOI: 10.1200/jco.1999.17.1.168] [Citation(s) in RCA: 290] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To present nomograms providing estimates of prostate-specific antigen (PSA) failure-free survival after radical prostatectomy (RP) or external-beam radiation therapy (RT) for men diagnosed during the PSA era with clinically localized disease. PATIENTS AND METHODS A Cox regression multivariable analysis was used to determine the prognostic significance of the pretreatment PSA level, 1992 American Joint Committee on Cancer (AJCC) clinical stage, and biopsy Gleason score in predicting the time to posttherapy PSA failure in 1,654 men with T1c,2 prostate cancer managed with either RP or RT. RESULTS Pretherapy PSA, AJCC clinical stage, and biopsy Gleason score were independent predictors (P < .0001) of time to posttherapy PSA failure in patients managed with either RP or RT. Two-year PSA failure rates derived from the Cox regression model and bootstrap estimates of the 95% confidence intervals are presented in the format of a nomogram stratified by the pretreatment PSA, AJCC clinical stage, biopsy Gleason score, and local treatment modality. CONCLUSION Men at high risk (> 50%) for early (< or = 2 years) PSA failure could be identified on the basis of the type of local therapy received and the clinical information obtained as part of the routine work-up for localized prostate cancer. Selection of these men for trials evaluating adjuvant systemic and improved local therapies may be justified.
Collapse
|
|
26 |
290 |