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Frautschy SA, Hu W, Kim P, Miller SA, Chu T, Harris-White ME, Cole GM. Phenolic anti-inflammatory antioxidant reversal of Abeta-induced cognitive deficits and neuropathology. Neurobiol Aging 2001; 22:993-1005. [PMID: 11755008 DOI: 10.1016/s0197-4580(01)00300-1] [Citation(s) in RCA: 350] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Both oxidative damage and inflammation have been implicated in age-related neurodegenerative diseases including Alzheimer's Disease (AD). The yellow curry spice, curcumin, has both antioxidant and anti-inflammatory activities which confer significant protection against neurotoxic and genotoxic agents. We used 22 month Sprague-Dawley (SD) rats to compare the effects of the conventional NSAID, ibuprofen, and curcumin for their ability to protect against amyloid beta-protein (Abeta)-induced damage. Lipoprotein carrier-mediated, intracerebroventricular infusion of Abeta peptides induced oxidative damage, synaptophysin loss, a microglial response and widespread Abeta deposits. Dietary curcumin (2000 ppm), but not ibuprofen, suppressed oxidative damage (isoprostane levels) and synaptophysin loss. Both ibuprofen and curcumin reduced microgliosis in cortical layers, but curcumin increased microglial labeling within and adjacent to Abeta-ir deposits. In a second group of middle-aged female SD rats, 500 ppm dietary curcumin prevented Abeta-infusion induced spatial memory deficits in the Morris Water Maze and post-synaptic density (PSD)-95 loss and reduced Abeta deposits. Because of its low side-effect profile and long history of safe use, curcumin may find clinical application for AD prevention.
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Donker RB, Mouillet JF, Chu T, Hubel CA, Stolz DB, Morelli AE, Sadovsky Y. The expression profile of C19MC microRNAs in primary human trophoblast cells and exosomes. Mol Hum Reprod 2012; 18:417-24. [PMID: 22383544 DOI: 10.1093/molehr/gas013] [Citation(s) in RCA: 261] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The largest gene cluster of human microRNAs (miRNAs), the chromosome 19 miRNA cluster (C19MC), is exclusively expressed in the placenta and in undifferentiated cells. The precise expression pattern and function of C19MC members are unknown. We sought to profile the relative expression of C19MC miRNAs in primary human trophoblast (PHT) cells and exosomes. Using high-throughput profiling, confirmed by PCR, we found that C19MC miRNAs are among the most abundant miRNAs in term human trophoblasts. Hypoxic stress selectively reduced miR-520c-3p expression at certain time-points with no effect on other C19MC miRNAs. Similarly, differentiation in vitro had a negligible effect on C19MC miRNAs. We found that C19MC miRNAs are the predominant miRNA species expressed in exosomes released from PHT, resembling the profile of trophoblastic cellular miRNA. Predictably, we detected the similar levels of circulating C19MC miRNAs in the serum of healthy pregnant women at term and in women with pregnancies complicated by fetal growth restriction. Our data define the relative expression levels of C19MC miRNAs in trophoblasts and exosomes, and suggest that C19MC miRNAs function in placental-maternal signaling.
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Research Support, U.S. Gov't, Non-P.H.S. |
13 |
261 |
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Lim GP, Yang F, Chu T, Gahtan E, Ubeda O, Beech W, Overmier JB, Hsiao-Ashec K, Frautschy SA, Cole GM. Ibuprofen effects on Alzheimer pathology and open field activity in APPsw transgenic mice. Neurobiol Aging 2001; 22:983-91. [PMID: 11755007 DOI: 10.1016/s0197-4580(01)00299-8] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We previously showed the non-steroidal anti-inflammatory drug (NSAID) ibuprofen suppresses inflammation and amyloid in the APPsw (Tg2576) Tg2576 transgenic mouse. The mechanism for these effects and the impact on behavior are unknown. We now show ibuprofen's effects were not mediated by alterations in amyloid precursor protein (APP) expression or oxidative damage (carbonyls). Six months ibuprofen treatment in Tg+ females caused a decrease in open field behavior (p < 0.05), restoring values similar to Tg- mice. Reduced caspase activation per plaque provided further evidence for a neuroprotective action of ibuprofen. The impact of a shorter 3 month duration ibuprofen trial, beginning at a later age (from 14 to 17 months), was also investigated. Repeated measures ANOVA of Abeta levels (soluble and insoluble) demonstrated a significant ibuprofen treatment effect (p < 0.05). Post-hoc analysis showed that ibuprofen-dependent reductions of both soluble Abeta and Abeta42 were most marked in entorhinal cortex (p < 0.05). Although interleukin-1beta and insoluble Abeta were more effectively reduced with longer treatment, the magnitude of the effect on soluble Abeta was not dependent on treatment duration.
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Smeyne RJ, Chu T, Lewin A, Bian F, Sanlioglu S, S-Crisman S, Kunsch C, Lira SA, Oberdick J. Local control of granule cell generation by cerebellar Purkinje cells. Mol Cell Neurosci 1995; 6:230-51. [PMID: 7496629 DOI: 10.1006/mcne.1995.1019] [Citation(s) in RCA: 169] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Cerebellar Purkinje cells were ablated by the specific expression of diphtheria toxin in these cells in transgenic mice. Purkinje cell degeneration during early postnatal development shows a zonally restricted pattern which has been exploited in order to look for local secondary effects. The most obvious early effect is the alignment of gaps in the Purkinje cell layer with dramatically thinned zones in the overlying EGL, the germinal layer from which granule cells are generated. Within these EGL zones in the transgenic mutant, markers that distinguish matrix from mantle cells demonstrate a preferential loss of the proliferative cells. Comparison of BrdU incorporation in the mutant vs wild-type confirms the reduction in proliferation. In the mutant, in situ labeling of DNA fragmentation associated with apoptotic cell death shows abundant labeling of granule cells that have exited the EGL, but not of progenitor cells in the EGL. Thus, although a trophic role for Purkinje cells has been well documented, these observations further suggest a mitogenic role which can be exerted locally.
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Chu T, Kumagai Y, DiStefano EW, Cho AK. Disposition of methylenedioxymethamphetamine and three metabolites in the brains of different rat strains and their possible roles in acute serotonin depletion. Biochem Pharmacol 1996; 51:789-96. [PMID: 8602874 DOI: 10.1016/0006-2952(95)02397-6] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
3,4-Methylenedioxymethamphetamine (MDMA) affects both dopamine and serotonin (5-HT) systems. One of its acute actions is to cause a reversible fall in steady-state brain 5-HT concentrations. To investigate the chemical basis of this acute effect, the brain levels of the parent compound and three major metabolites, 3,4- 3,4-methylenedioxyamphetamine (MDA), 3,4-dihydroxymethamphetamine (DHMA) and 6-hydroxy-3,4-methylenedioxymethamphetamine (6-OHMDMA), were monitored, together with 5-HT levels, over a period of 6 hr in male Sprague-Dawley (SD) rats. The temporal relationships between drug concentrations of both stereoisomers and depletions were evaluated first. There was no correlation between the concentrations of the compounds measured and the extent of 5-HT depletion. Brain levels of MDMA and MDA were higher than plasma levels and exhibited a stereoselectivity in that (-)-MDMA and (+)-MDA levels were higher than those of enantiomers. The relationship between the dose of ((+)-MDMA and reduction in 5-HT levels was next investigated in SD male, SD female, and Dark Agouti (DA) female rats. These animals exhibit different capabilities of MDMA metabolism. There is a lower level of MDA, the N-demethylated metabolite of MDMA, in female SD rats than in males. Female DA rats are deficient in CYP2D isozymes, one of the enzymes responsible for demethylenation of MDMA to DHMA at pharmacological concentrations of substrate. there was a significant accuulation of MDMA in the brain and plasma of DA rats, but their 5-HT depletion was somewhat attenuated. The results indicated that MDMA ++ was apparently not the single, causative agent for the acute 5-HT depletion, which may also involve a metabolite formed by CYP2D.
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Mouillet JF, Chu T, Hubel CA, Nelson DM, Parks WT, Sadovsky Y. The levels of hypoxia-regulated microRNAs in plasma of pregnant women with fetal growth restriction. Placenta 2010; 31:781-4. [PMID: 20667590 DOI: 10.1016/j.placenta.2010.07.001] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 06/30/2010] [Accepted: 07/02/2010] [Indexed: 12/27/2022]
Abstract
MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression at the post-transcriptional level. While mostly intracellular, a portion of cellular miRNAs is released to the circulation and their level in the plasma is altered in certain pathological conditions such as cancer, and also during pregnancy. We examined the circulating levels of a set of trophoblastic miRNAs, which we recently found to be regulated by hypoxia, in the plasma of pregnant women with fetal growth restriction (FGR). Pregnancy was associated with increased plasma levels of several placenta-specific miRNAs, compared to non-pregnant controls. Among pregnant women, the overall levels of miRNA species that we analyzed were increased by 1.84-fold (p < or = 0.01) in plasma of women with pregnancies complicated by FGR, but decreased in FGR placentas by 24% (p < or = 0.01) compared to values from uncomplicated pregnancies. Together, our results show that plasma concentration of miRNAs is regulated in pregnancy, and that FGR is associated with increased circulating miRNA levels, highlighting the need to explore plasma miRNAs as potential biomarkers for placental diseases.
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Research Support, Non-U.S. Gov't |
15 |
114 |
7
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Morihara T, Chu T, Ubeda O, Beech W, Cole GM. Selective inhibition of Abeta42 production by NSAID R-enantiomers. J Neurochem 2002; 83:1009-12. [PMID: 12421374 DOI: 10.1046/j.1471-4159.2002.01195.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Non-steroidal anti-inflammatory drugs (NSAIDs) have been associated with reduced risk for Alzheimer's disease (AD) and selected NSAIDs racemates suppress beta-amyloid (Abeta) accumulation in vivo and Abeta42 production in vitro. Clinical use of NSAIDs for preventing or treating AD has been hampered by dose-limiting toxicity believed to be due to cyclooxygenase (COX)-inhibition that is reportedly not essential for selective Abeta42 reduction. Profens have racemates and R-enantiomers were supposed to be inactive forms. Here we demonstrate that R-ibuprofen and R-flurbiprofen, with poor COX-inhibiting activity, reduce Abeta42 production by human cells. Although these R-enantiomers inhibit nuclear factor-kappaB (NF-kappaB) activation and NF-kappaB can selectively regulate Abeta42, Abeta42 reduction is not mediated by inhibition of NF-kappaB activation. Because of its efficacy at lowering Abeta42 production and low toxicity profile, R-flurbiprofen is a strong candidate for clinical development.
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Peng Y, Moe OW, Chu T, Preisig PA, Yanagisawa M, Alpern RJ. ETB receptor activation leads to activation and phosphorylation of NHE3. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:C938-45. [PMID: 10199826 DOI: 10.1152/ajpcell.1999.276.4.c938] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In OKP cells expressing ETB endothelin receptors, activation of Na+/H+ antiporter activity by endothelin-1 (ET-1) was resistant to low concentrations of ethylisopropyl amiloride, indicating regulation of Na+/H+ exchanger isoform 3 (NHE3). ET-1 increased NHE3 phosphorylation in cells expressing ETB receptors but not in cells expressing ETA receptors. Receptor specificity was not due to demonstrable differences in receptor-specific activation of tyrosine phosphorylation pathways or inhibition of adenylyl cyclase. Phosphorylation was associated with a decrease in mobility on SDS-PAGE, which was reversed by treating immunoprecipitated NHE3 with alkaline phosphatase. Phosphorylation was first seen at 5 min and was maximal at 15-30 min. Phosphorylation was maximal with 10(-9) M ET-1. Phosphorylation occurred on threonine and serine residues at multiple sites. In summary, ET-1 induces NHE3 phosphorylation in OKP cells on multiple threonine and serine residues. ETB receptor specificity, time course, and concentration dependence are all similar between ET-1-induced increases in NHE3 activity and phosphorylation, suggesting that phosphorylation plays a key role in activation.
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99 |
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Valli-Pulaski H, Peters KA, Gassei K, Steimer SR, Sukhwani M, Hermann BP, Dwomor L, David S, Fayomi AP, Munyoki SK, Chu T, Chaudhry R, Cannon GM, Fox PJ, Jaffe TM, Sanfilippo JS, Menke MN, Lunenfeld E, Abofoul-Azab M, Sender LS, Messina J, Klimpel LM, Gosiengfiao Y, Rowell EE, Hsieh MH, Granberg CF, Reddy PP, Sandlow JI, Huleihel M, Orwig KE. Testicular tissue cryopreservation: 8 years of experience from a coordinated network of academic centers. Hum Reprod 2019; 34:966-977. [PMID: 31111889 PMCID: PMC6554046 DOI: 10.1093/humrep/dez043] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 02/28/2019] [Indexed: 12/31/2022] Open
Abstract
STUDY QUESTION Is it feasible to disseminate testicular tissue cryopreservation with a standardized protocol through a coordinated network of centers and provide centralized processing/freezing for centers that do not have those capabilities? SUMMARY ANSWER Centralized processing and freezing of testicular tissue from multiple sites is feasible and accelerates recruitment, providing the statistical power to make inferences that may inform fertility preservation practice. WHAT IS KNOWN ALREADY Several centers in the USA and abroad are preserving testicular biopsies for patients who cannot preserve sperm in anticipation that cell- or tissue-based therapies can be used in the future to generate sperm and offspring. STUDY DESIGN, SIZE, DURATION Testicular tissue samples from 189 patients were cryopreserved between January 2011 and November 2018. Medical diagnosis, previous chemotherapy exposure, tissue weight, and presence of germ cells were recorded. PARTICIPANTS/MATERIALS, SETTING, METHODS Human testicular tissue samples were obtained from patients undergoing treatments likely to cause infertility. Twenty five percent of the patient's tissue was donated to research and 75% was stored for patient's future use. The tissue was weighed, and research tissue was fixed for histological analysis with Periodic acid-Schiff hematoxylin staining and/or immunofluorescence staining for DEAD-box helicase 4, and/or undifferentiated embryonic cell transcription factor 1. MAIN RESULTS AND THE ROLE OF CHANCE The average age of fertility preservation patients was 7.9 (SD = 5) years and ranged from 5 months to 34 years. The average amount of tissue collected was 411.3 (SD = 837.3) mg and ranged from 14.4 mg-6880.2 mg. Malignancies (n = 118) were the most common indication for testicular tissue freezing, followed by blood disorders (n = 45) and other conditions (n = 26). Thirty nine percent (n = 74) of patients had initiated their chemotherapy prior to undergoing testicular biopsy. Of the 189 patients recruited to date, 137 have been analyzed for the presence of germ cells and germ cells were confirmed in 132. LIMITATIONS, REASONS FOR CAUTION This is a descriptive study of testicular tissues obtained from patients who were at risk of infertility. The function of spermatogonia in those biopsies could not be tested by transplantation due limited sample size. WIDER IMPLICATIONS OF THE FINDINGS Patients and/or guardians are willing to pursue an experimental fertility preservation procedure when no alternatives are available. Our coordinated network of centers found that many patients request fertility preservation after initiating gonadotoxic therapies. This study demonstrates that undifferentiated stem and progenitor spermatogonia may be recovered from the testicular tissues of patients who are in the early stages of their treatment and have not yet received an ablative dose of therapy. The function of those spermatogonia was not tested. STUDY FUNDING/COMPETING INTEREST(S) Support for the research was from the Eunice Kennedy Shriver National Institute for Child Health and Human Development grants HD061289 and HD092084, the Scaife Foundation, the Richard King Mellon Foundation, the Departments of Ob/Gyn & Reproductive Sciences and Urology of the University of Pittsburgh Medical Center, United States-Israel Binational Science Foundation (BSF), and the Kahn Foundation. The authors declare that they do not have competing financial interests.
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Research Support, N.I.H., Extramural |
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99 |
10
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Melkonian KA, Chu T, Tortorella LB, Brown DA. Characterization of proteins in detergent-resistant membrane complexes from Madin-Darby canine kidney epithelial cells. Biochemistry 1995; 34:16161-70. [PMID: 8519773 DOI: 10.1021/bi00049a031] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We previously isolated detergent-resistant membrane complexes (DRMs) that were not solubilized after extraction of Madin-Darby canine kidney cells with Triton X-100 on ice. The complexes were rich in glycosphingolipids, cholesterol, and glycosylphosphatidylinositol (GPI)-anchored proteins. In this study, we examined the protein composition of DRMs and further characterized the detergent solubility of these structures. Eight to ten cell-surface proteins, including proteins from both apical and basolateral membranes, were recovered in DRMs. Most DRM proteins, however, were not exposed to the surface of whole cells, and we did not detect the complex of cell-surface proteins described by Sargiacomo et al. in a similar study [Sargiacomo, M., et al. (1993) J. Cell Biol. 122, 789-807]. Almost all proteins in DRMs were solubilized by Triton X-100 at temperatures above 30 degrees C or by octyl glucoside on ice. In contrast, a GPI-anchored protein, placental alkaline phosphatase, was mostly solubilized by Triton X-100 after extraction at 10 degrees C. This protein was insoluble in ice-cold Triton X-100 when first delivered to the plasma membrane and remained so for at least 6 h after synthesis. A fraction of the lipids in DRMs remained insoluble after extraction with Triton X-100 at 37 degrees C. DRM lipids were not solubilized by octyl glucoside, suggesting that this detergent selectively extracts proteins from DRMs.
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Johnston C, Jiang W, Chu T, Levine B. Identification of genes involved in the host response to neurovirulent alphavirus infection. J Virol 2001; 75:10431-45. [PMID: 11581411 PMCID: PMC114617 DOI: 10.1128/jvi.75.21.10431-10445.2001] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Single-amino-acid mutations in Sindbis virus proteins can convert clinically silent encephalitis into uniformly lethal disease. However, little is known about the host gene response during avirulent and virulent central nervous system (CNS) infections. To identify candidate host genes that modulate alphavirus neurovirulence, we utilized GeneChip Expression analysis to compare CNS gene expression in mice infected with two strains of Sindbis virus that differ by one amino acid in the E2 envelope glycoprotein. Infection with Sindbis virus, dsTE12H (E2-55 HIS), resulted in 100% mortality in 10-day-old mice, whereas no disease was observed in mice infected with dsTE12Q (E2-55 GLN). dsTE12H, compared with dsTE12Q, replicated to higher titers in mouse brain and induced more CNS apoptosis. Infection with the neurovirulent dsTE12H strain was associated with both a greater number of host genes with increased expression and greater changes in levels of host gene expression than was infection with the nonvirulent dsTE12Q strain. In particular, dsTE12H infection resulted in greater increases in the levels of mRNAs encoding chemokines, proteins involved in antigen presentation and protein degradation, complement proteins, interferon-regulated proteins, and mitochondrial proteins. At least some of these increases may be beneficial for the host, as evidenced by the demonstration that enforced expression of the antiapoptotic mitochondrial protein peripheral benzodiazepine receptor (PBR) protects neonatal mice against lethal Sindbis virus infection. Thus, our findings identify specific host genes that may play a role in the host protective or pathologic response to neurovirulent Sindbis virus infection.
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research-article |
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82 |
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Letter |
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Teter B, Morihara T, Lim GP, Chu T, Jones MR, Zuo X, Paul RM, Frautschy SA, Cole GM. Curcumin restores innate immune Alzheimer's disease risk gene expression to ameliorate Alzheimer pathogenesis. Neurobiol Dis 2019; 127:432-448. [PMID: 30951849 PMCID: PMC8092921 DOI: 10.1016/j.nbd.2019.02.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 02/15/2019] [Accepted: 02/20/2019] [Indexed: 01/28/2023] Open
Abstract
Alzheimer's disease (AD) genetics implies a causal role for innate immune genes, TREM2 and CD33, products that oppose each other in the downstream Syk tyrosine kinase pathway, activating microglial phagocytosis of amyloid (Aβ). We report effects of low (Curc-lo) and high (Curc-hi) doses of curcumin on neuroinflammation in APPsw transgenic mice. Results showed that Curc-lo decreased CD33 and increased TREM2 expression (predicted to decrease AD risk) and also increased TyroBP, which controls a neuroinflammatory gene network implicated in AD as well as phagocytosis markers CD68 and Arg1. Curc-lo coordinately restored tightly correlated relationships between these genes' expression levels, and decreased expression of genes characteristic of toxic pro-inflammatory M1 microglia (CD11b, iNOS, COX-2, IL1β). In contrast, very high dose curcumin did not show these effects, failed to clear amyloid plaques, and dysregulated gene expression relationships. Curc-lo stimulated microglial migration to and phagocytosis of amyloid plaques both in vivo and in ex vivo assays of sections of human AD brain and of mouse brain. Curcumin also reduced levels of miR-155, a micro-RNA reported to drive a neurodegenerative microglial phenotype. In conditions without amyloid (human microglial cells in vitro, aged wild-type mice), Curc-lo similarly decreased CD33 and increased TREM2. Like curcumin, anti-Aβ antibody (also reported to engage the Syk pathway, increase CD68, and decrease amyloid burden in human and mouse brain) increased TREM2 in APPsw mice and decreased amyloid in human AD sections ex vivo. We conclude that curcumin is an immunomodulatory treatment capable of emulating anti-Aβ vaccine in stimulating phagocytic clearance of amyloid by reducing CD33 and increasing TREM2 and TyroBP, while restoring neuroinflammatory networks implicated in neurodegenerative diseases.
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Research Support, N.I.H., Extramural |
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73 |
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Chen B, Chu T, Harms E, Gergen JP, Strickland S. Mapping of Drosophila mutations using site-specific male recombination. Genetics 1998; 149:157-63. [PMID: 9584093 PMCID: PMC1460155 DOI: 10.1093/genetics/149.1.157] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Although recombination does not usually occur in the male Drosophila germline, site-specific recombination can be induced at the ends of P elements. This finding suggested that male recombination could be used to map Drosophila mutations. In this article, we describe the general method and its application to the mapping of two EMS-induced female-sterile mutations, grauzone and cortex. Within two months, the grauzone gene was mapped relative to seven different P-element insertion sites, and cortex was mapped relative to 23 different P-elements. The results allowed us to map grauzone to a region of about 50 kb, and cortex distal to the chromosomal region 33E. These experiments demonstrate that P-element-induced site-specific male recombination is an efficient and general method to map Drosophila autosomal mutations.
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research-article |
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Lieberfarb ME, Chu T, Wreden C, Theurkauf W, Gergen JP, Strickland S. Mutations that perturb poly(A)-dependent maternal mRNA activation block the initiation of development. Development 1996; 122:579-88. [PMID: 8625809 DOI: 10.1242/dev.122.2.579] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Translational recruitment of maternal mRNAs is an essential process in early metazoan development. To identify genes required for this regulatory pathway, we have examined a collection of Drosophila female-sterile mutants for defects in translation of maternal mRNAs. This strategy has revealed that maternal-effect mutations in the cortex and grauzone genes impair translational activation and cytoplasmic polyadenylation of bicoid and Toll mRNAs. Cortex embryos contain a bicoid mRNA indistinguishable in amount, localization, and structure from that in wild-type embryos. However, the bicoid mRNA in cortex embryos contains a shorter than normal polyadenosine (poly(A)) tail. Injection of polyadenylated bicoid mRNA into cortex embryos allows translation demonstrating that insufficient polyadenylation prevents endogenous bicoid mRNA translation. In contrast nanos mRNA, which is activated by a poly(A)-independent mechanism, is translated in cortex embryos, indicating that the block in maternal mRNA activation is specific to a class of mRNAs. Cortex embryos are fertilized, but arrest at the onset of embryogenesis. Characterization of grauzone mutations indicates that the phenotype of these embryos is similar to cortex. These results identify a fundamental pathway that serves a vital role in the initiation of development.
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Shalev S, Lee T, Leszczynski K, Cosby S, Chu T, Reinstein L, Meek A. Video techniques for on-line portal imaging. Comput Med Imaging Graph 1989; 13:217-26. [PMID: 2655876 DOI: 10.1016/0895-6111(89)90128-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The application of on-line portal imaging techniques to the verification of treatment precision is reviewed. The design parameters for a video portal imaging system are described, and the optimization of image quality is discussed with particular emphasis on photon noise. On-line images are presented for a head phantom imaged on a 4 MV linac, and compared with a conventional portal film. The relative advantages of an on-line system are compared with conventional portal film analysis.
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Review |
36 |
55 |
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Chu T, Henrion G, Haegeli V, Strickland S. Cortex, a Drosophila gene required to complete oocyte meiosis, is a member of the Cdc20/fizzy protein family. Genesis 2001; 29:141-52. [PMID: 11252055 DOI: 10.1002/gene.1017] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mutations in cortex and grauzone cause abnormal arrest in Drosophila female meiosis. cortex was mapped to a 14 kb interval in 26F-27A by the male recombination mapping method. While these experiments mapped the gene accurately, they also illustrated some complexities of this method. Rescue results showed that a 2.8 kb genomic fragment from this interval was able to fully rescue the cortex phenotype. The 2.8 kb rescuing fragment contains a single open reading frame. The predicted amino acid sequence indicates that cortex encodes a WD-repeat protein and is a distant member of the Cdc20 protein family. Results from a developmental Northern analysis showed that the cortex transcript is expressed at high levels during oogenesis and early embryogenesis. Interestingly, the meiotic metaphase-anaphase II arrest defect in embryos laid by cortex homozygous females resembles the mitotic metaphase-anaphase defects observed in yeast cdc20 mutants. The predicted nature of the Cortex protein, together with the observed meiotic phenotype in cortex mutants, suggest that a similar pathway to the cdc20 dependent APC-mediated proteolysis pathway, which governs the metaphase-anaphase transition in mitosis, is also important in regulating oocyte meiosis.
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McLelland J, Rees A, Williams G, Chu T. The incidence of immunosuppression-related skin disease in long-term transplant patients. Transplantation 1988; 46:871-4. [PMID: 3061083 DOI: 10.1097/00007890-198812000-00016] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
One hundred and twenty-one patients who had received a renal allograft between 4 months and 21 years previously (mean +/- SD, 71 +/- 62 months) were studied. Seventy-two patients were conventionally immunosuppressed with azathioprine and prednisolone, and 36 had been exposed to the current regime of cyclosporine, azathioprine, and prednisolone. Forty-five patients had viral warts, of whom 20 had more than 10 warts. The presence of viral warts was significantly associated with pale skin type, excess sun exposure, and with duration of allograft. Viral warts were significantly more common in those on conventional immunosuppressive therapy, but this could be solely a reflection of the difference in duration of transplant between the 2 groups. Twelve patients were found to have developed dysplastic or neoplastic skin lesions since transplantation. The incidence of dysplasia increased with increasing age and was significantly associated with pale skin type, excess sun exposure, and duration of allograft. Despite the shorter duration of treatment in those on the new treatment regime, there was no difference between the 2 groups in the proportion of patients with dysplastic skin lesions. Immunosuppression-related skin disease may be a significant problem in allograft recipients in this country, and we suspect that patients taking cyclosporine will have similar problems to those on conventional immunosuppressive drugs alone. Immunosuppressed patients should be advised to avoid sun exposure, to use sunscreens, and should be monitored carefully for the development of dysplastic lesions.
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Comparative Study |
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Bian F, Chu T, Schilling K, Oberdick J. Differential mRNA transport and the regulation of protein synthesis: selective sensitivity of Purkinje cell dendritic mRNAs to translational inhibition. Mol Cell Neurosci 1996; 7:116-33. [PMID: 8731480 DOI: 10.1006/mcne.1996.0009] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Although the majority of mRNAs expressed in neurons are confined to the perikaryon, a growing number appear to be transported into dendrites. It is likely that this allows for the local regulation of protein synthesis within discrete subcellular compartments. Here, three different subcellular distribution patterns are demonstrated for four mRNAs that encode proteins highly expressed in Purkinje cells and their dendrites; mRNAs are found in the perikaryon only, perikaryon and proximal dendrite, or perikaryon and proximal plus distal dendrites. Further, it is shown that transport of an mRNA into the dendrites increases its sensitivity to translational inhibition by diphtheria toxin. These data suggest a simple model whereby the transport machinery can regulate the translation of selected mRNAs. Thus, environmental signals that generally affect translational efficiency in concert with the selectivity provided by the transport machinery could provide a means to locally regulate the synthesis of a restricted pool of proteins.
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Bowlus CL, Ahn J, Chu T, Gruen JR. Cloning of a novel MHC-encoded serine peptidase highly expressed by cortical epithelial cells of the thymus. Cell Immunol 1999; 196:80-6. [PMID: 10527559 DOI: 10.1006/cimm.1999.1543] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Antigen presentation by cortical thymic epithelial cells (cTEC) during the positive selection of T cells has been shown to differ from that of other antigen-presenting cells. In the case of MHC class II presentation, cathepsin L as opposed to cathepsin S is responsible at least in part for the degradation of invariant chain. Other proteases, however, must be involved. We have identified a putative serine protease that is specifically expressed in the thymus. Encoded within the class I major histocompatibility complex (MHC) region, this gene has sequence homology with lysosomal prolylcarboxypeptidase, suggesting that it is a serine protease. We have, therefore, designated this gene thymus-specific serine protease (TSSP). In situ hybridization and immunofluorescence staining reveal that TSSP is expressed exclusively by cortical thymic epithelial cells, with the strongest staining noted around vessels and the thymic capsule. The identification of TSSP further supports the theory that MHC class II antigen processing and presentation in the thymic cortex involves a proteolytic milieu that differs from that of other antigen-presenting cells.
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Comparative Study |
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Abstract
Langerhans cell histiocytosis is a rare condition that can affect any organ of the body. Patients of all ages may present to the dermatologist and it is important to make the diagnosis as quickly as possible, because time from presentation to diagnosis is of prognostic importance in adults with the disease. Langerhans cell histiocytosis is now classified as a class I histiocytosis and research into this disease has been very active over the past 10 years. We now know that the disease represents a clonal expansion of a Langerhans cell, which shows phenotypic evidence of activation. The tissue damage induced by the disease appears to be related to local cytokine release. In single system disease, Langerhans cell histiocytosis is responsive to local therapy but, in resistant single system disease or in multisystem disease, etoposide is the most effective monochemotherapy. Some patients will need maintenance treatment with azathioprine or 6-mercaptopurine with or without methotrexate. In such cases, physicians who are used to treating chronic and relapsing diseases and who have experience with these drugs, such as dermatologists, are the most appropriate to manage patients with Langerhans cell histiocytosis.
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Review |
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Chu T, Dufort I, Sirard MA. Effect of ovarian stimulation on oocyte gene expression in cattle. Theriogenology 2012; 77:1928-38. [PMID: 22444561 DOI: 10.1016/j.theriogenology.2012.01.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 11/01/2011] [Accepted: 01/21/2012] [Indexed: 11/19/2022]
Abstract
The objective was to analyze the impact of follicle stimulating hormone (FSH, ovarian stimulation) on the transcriptome of in vivo bovine oocytes three times around the luteinizing hormone (LH) surge. In vivo bovine oocytes were collected 2 h pre-LH surge, 6 h post-LH surge, and 22 h post-LH surge in both naturally ovulating and superovulated animals. To assess potential changes in gene levels, samples were hybridized using a custom bovine microarray. Two series of hybridizations were performed: the first comparing natural vs. stimulated cycles, the second according to time of collection. Among the potential candidates, 13 genes were selected according to their degree of differential expression and their potential link to oocyte competence. Measurements of their relative mRNA levels was made using QPCR. Gene candidates BTG4 (P = 0.0006), PTTG1 (P = 0.0027), PAPOLA (P = 0.0245), and LEO1 (P = 0.0393) had higher mRNA levels in oocytes treated with FSH for all collection times when compared to oocytes produced through the natural cycle. Among our selected candidates, only one gene, GDF9 (P = 0.0261), was present at a higher level in oocytes collected at -2 h and 6 h than 22 h post-LH for all treatments, regardless of the presence of FSH. Although the number of genes influenced by ovarian stimulation seemed low, the observed differences occurred at a time of minimal transcriptional activity and supported the potential impact on the future embryo. These impacts could have been epigenetic in nature, as embryo quality was not reported to be different from stimulated animals.
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Research Support, Non-U.S. Gov't |
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43 |
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Chu T, Chandhoke RA, Smith PC, Schwaitzberg SD. The impact of surgeon choice on the cost of performing laparoscopic appendectomy. Surg Endosc 2010; 25:1187-91. [PMID: 20835717 DOI: 10.1007/s00464-010-1342-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 08/17/2010] [Indexed: 12/19/2022]
Abstract
INTRODUCTION While laparoscopic appendectomy (LA) can be performed using a myriad of techniques, the cost of each method varies. The purpose of this study is to analyze the effects of surgeon choice of technique on the cost of key steps in LA. METHODS Surgeon operative notes, hospital invoice lists, and surgeon instrumentation preference sheets were obtained for all LA cases in 2008 at Cambridge Health Alliance (CHA). Only cases (N = 89) performed by fulltime staff general surgeons (N = 8) were analyzed. Disposable costs were calculated for the following components of LA: port access, mesoappendix division, and management of the appendiceal stump. The actual cost of each disposable was determined based on the hospital's materials management database. Actual hospital reimbursements for LA in 2008 were obtained for all payers and compared with the disposable cost per case. RESULTS Disposable cost per case for the three portions analyzed for 126 theoretical models were calculated and found to range from US $81 to US $873. The surgeon with the most cost-effective preferred method (US $299) utilized one multi-use endoscopic clip applier for mesoappendix division, two commercially available pretied loops for management of the appendiceal stump, and three 5-mm trocars as their preferred technique. The surgeon with the least cost-effective preferred method (US $552) utilized two staple firings for mesoappendix division, one staple firing for management of the appendiceal stump, and 12/5/10-mm trocars for access. The two main payers for LA patients were Medicaid and Health Safety Net, whose total hospital reimbursements ranged from US $264 to US $504 and from US $0 to US $545 per case, respectively, for patients discharged on day 1. DISCUSSION Disposable costs frequently exceeded hospital reimbursements. Currently, there is no scientific literature that clearly illustrates a superior surgical method for performing these portions of LA in routine cases. This study suggests that surgeons should review the cost implications of their practice and to find ways to provide the most cost-effective care without jeopardizing clinical outcome.
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Journal Article |
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Mega MS, Chu T, Mazziotta JC, Trivedi KH, Thompson PM, Shah A, Cole G, Frautschy SA, Toga AW. Mapping biochemistry to metabolism: FDG-PET and amyloid burden in Alzheimer's disease. Neuroreport 1999; 10:2911-7. [PMID: 10549796 DOI: 10.1097/00001756-199909290-00007] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We evaluated the relationship between amyloid-beta protein (A beta) concentration and the metabolic abnormality in an Alzheimer's disease (AD) patient as measured by [18F]fluorodeoxyglucose positron emission tomography (FDG-PET). Across most regions there were significant inverse correlations among FDG-PET intensity values and both insoluble. The temporal lobe samples showed no significant correlation between FDG-PET values and A beta deposition. Findings support A beta as contributing to the hypometabolism in regions of the AD brain that are still relatively viable metabolically; those regions with chronic pathologic damage, such as temporal cortex, may have other factors that contribute to metabolic deficits.
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Case Reports |
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Yeung AT, Jones BK, Capraro M, Chu T. The repair of psoralen monoadducts by the Escherichia coli UvrABC endonuclease. Nucleic Acids Res 1987; 15:4957-71. [PMID: 3299260 PMCID: PMC305930 DOI: 10.1093/nar/15.12.4957] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We have examined the interactions of UvrABC endonuclease with DNA containing the monoadducts of 8-methoxypsoralen (8-MOP) and 4,5',8-trimethylpsoralen (TMP). The UvrA and UvrB proteins were found to form a stable complex on DNA that contains the psoralen monoadducts. Subsequent binding of UvrC protein to this complex activates the UvrABC endonuclease activity. As in the case of incision at pyrimidine dimers, a stable protein-DNA complex was observed after the incision events. For both 8-MOP and TMP, the UvrABC endonuclease incised the monoadduct-containing strand of DNA on the two sides of the monoadduct with 12 bases included between the two cuts. One incision was at the 8th phosphodiester bond on the 5' side of the modified base. The other incision was at the 5th phosphodiester bond 3' to the modified base. The UvrABC endonuclease incision data revealed that the reactivity of psoralens is 5'TpA greater than 5'ApT greater than 5'TpG.
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research-article |
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