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Sheikh HA, Maher BA, Woods AW, Tung PY, Harrison RJ. Efficacy of green infrastructure in reducing exposure to local, traffic-related sources of airborne particulate matter (PM). Sci Total Environ 2023; 903:166598. [PMID: 37634712 DOI: 10.1016/j.scitotenv.2023.166598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/24/2023] [Accepted: 08/24/2023] [Indexed: 08/29/2023]
Abstract
One aim of roadside green infrastructure (GI) is to mitigate exposure to local, traffic-generated pollutants. Here, we determine the efficacy of roadside GI in improving local air quality through the deposition and/or dispersion of airborne particulate matter (PM). PM was collected on both pumped air filters and on the leaves of a recently installed 'tredge' (trees managed as a head-high hedge) at an open road environment next to a primary school in Manchester, U.K. The magnetic properties of PM deposited on leaves and filters (size fractions PM10 and PM2.5) were deduced from hysteresis loops, first-order reversal curves (FORCs), and low-temperature remanence measurements. These were complemented with electron microscopy to identify changes in magnetic PM concentration downwind of the tredge/GI. We show that the tredge is permeable to airflow using a simple CO2 tracer experiment; hence, it allows interception and subsequent deposition of PM on its leaves. Magnetic loadings per m3 of air from filters (PM10 saturation magnetisation, Ms, at 5 K) were reduced by 40 % behind the tredge and a further 63 % in the playground; a total reduction of 78 % compared to roadside air. For the PM2.5 fraction, the reduction in magnetic loading behind the tredge was remarkable (82 %), reflecting efficient diffusional capture of sub-5 nm Fe-oxide particles by the tredge. Some direct mixing of roadside and playground air occurs at the back of the playground, caused by air flow over, and/or through gaps in, the slowly-permeable tredge. The magnetic loading on tredge leaves increased over successive days, capturing ~23 % of local, traffic-derived PM10. Using a heuristic two-dimensional turbulent mixing model, we assess the limited dispersion of PM < 22.5 μm induced by eddies in the tredge wake. This study demonstrates that PM deposition on leaves reduces exposure significantly in this school playground setting; hence, providing a cost-effective mitigation strategy.
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Affiliation(s)
- H A Sheikh
- Department of Earth Sciences, University of Cambridge, Downing Site, CB2 3EQ, UK.
| | - B A Maher
- Center for Environmental Magnetism and Palaeomagnetism, University of Lancaster, LA1 4YQ, UK
| | - A W Woods
- Department of Earth Sciences, University of Cambridge, Downing Site, CB2 3EQ, UK
| | - P Y Tung
- Department of Earth Sciences, University of Cambridge, Downing Site, CB2 3EQ, UK; Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS, UK
| | - R J Harrison
- Department of Earth Sciences, University of Cambridge, Downing Site, CB2 3EQ, UK
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Klein RH, Tung PY, Somanath P, Fehling HJ, Knoepfler PS. Genomic functions of developmental pluripotency associated factor 4 (Dppa4) in pluripotent stem cells and cancer. Stem Cell Res 2018; 31:83-94. [PMID: 30031967 PMCID: PMC6133722 DOI: 10.1016/j.scr.2018.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 12/20/2022] Open
Abstract
Developmental pluripotency associated factor 4 (Dppa4) is a highly specific marker of pluripotent cells, and is also overexpressed in certain cancers, but its function in either of these contexts is poorly understood. In this study, we use ChIP-Seq to identify Dppa4 binding genome-wide in three distinct cell types: mouse embryonic stem cells (mESC), embryonal carcinoma cells, and 3T3 fibroblasts ectopically expressing Dppa4. We find a core set of Dppa4 binding sites shared across cell types, and also a substantial number of sites unique to each cell type. Across cell types Dppa4 shows a preference for binding to regions with active chromatin signatures, and can influence chromatin modifications at target genes. In 3T3 fibroblasts with enforced Dppa4 expression, Dppa4 represses the cell cycle inhibitor Cdkn2c and activates Ets family transcription factor Etv4, leading to alterations in the cell cycle that likely contribute to the oncogenic phenotype. Dppa4 also directly regulates Etv4 in mESC but represses it in this context, and binds with Oct4 to a set of shared targets that are largely independent of Sox2 and Nanog, indicating that Dppa4 functions independently of the core pluripotency network in stem cells. Together these data provide novel insights into Dppa4 function in both pluripotent and oncogenic contexts.
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Affiliation(s)
- Rachel Herndon Klein
- Department of Cell Biology and Human Anatomy, University of California, Davis, 1 Shields Ave, Davis, CA 95616, United States.; Institute of Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, CA 95817, United States
| | - Po-Yuan Tung
- Department of Cell Biology and Human Anatomy, University of California, Davis, 1 Shields Ave, Davis, CA 95616, United States.; Institute of Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, CA 95817, United States
| | - Priyanka Somanath
- Department of Cell Biology and Human Anatomy, University of California, Davis, 1 Shields Ave, Davis, CA 95616, United States.; Institute of Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, CA 95817, United States
| | | | - Paul S Knoepfler
- Department of Cell Biology and Human Anatomy, University of California, Davis, 1 Shields Ave, Davis, CA 95616, United States.; Institute of Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, CA 95817, United States.
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Tung PY, Varlakhanova NV, Knoepfler PS. Identification of DPPA4 and DPPA2 as a novel family of pluripotency-related oncogenes. Stem Cells 2014; 31:2330-42. [PMID: 23963736 DOI: 10.1002/stem.1526] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 07/07/2013] [Accepted: 07/07/2013] [Indexed: 11/07/2022]
Abstract
In order to identify novel pluripotency-related oncogenes, an expression screen for oncogenic foci-inducing genes within a retroviral human embryonic stem cell cDNA library was conducted. From this screen, we identified not only known oncogenes but also intriguingly the key pluripotency factor, DPPA4 (developmental pluripotency-associated four) that encodes a DNA binding SAP domain-containing protein. DPPA4 has not been previously identified as an oncogene but is highly expressed in embryonal carcinomas, pluripotent germ cell tumors, and other cancers. DPPA4 is also mutated in some cancers. In direct transformation assays, we validated that DPPA4 is an oncogene in both mouse 3T3 cells and immortalized human dermal fibroblasts. Overexpression of DPPA4 generates oncogenic foci (sarcoma cells) and causes anchorage-independent growth. The in vitro transformed cells also give rise to tumors in immunodeficient mice. Furthermore, functional analyses indicate that both the DNA-binding SAP domain and the histone-binding C-terminal domain are critical for the oncogenic transformation activity of DPPA4. Downregulation of DPPA4 in E14 mouse embryonic stem cells and P19 mouse embryonic carcinoma cells causes decreased cell proliferation in each case. In addition, DPPA4 overexpression induces cell proliferation through genes related to regulation of G1/S transition. Interestingly, we observed similar findings for family member DPPA2. Thus, we have identified a new family of pluripotency-related oncogenes consisting of DPPA2 and DPPA4. Our findings have important implications for stem cell biology and tumorigenesis.
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Affiliation(s)
- Po-Yuan Tung
- Department of Cell Biology and Human Anatomy, University of California Davis School of Medicine, Davis, California, USA; University of California Davis Genome Center, University of California Davis, Davis, California, USA; UC Davis Comprehensive Cancer Center, Shriners Hospital For Children Northern California, Sacramento, California, USA; Institute of Pediatric Regenerative Medicine, Shriners Hospital For Children Northern California, Sacramento, California, USA
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Chen Y, Chen CH, Tung PY, Huang SH, Wang SM. An acidic extracellular pH disrupts adherens junctions in HepG2 cells by Src kinases-dependent modification of E-cadherin. J Cell Biochem 2009; 108:851-9. [DOI: 10.1002/jcb.22313] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chen KH, Tung PY, Wu JC, Chen Y, Chen PC, Huang SH, Wang SM. An acidic extracellular pH induces Src kinase-dependent loss of beta-catenin from the adherens junction. Cancer Lett 2008; 267:37-48. [PMID: 18423982 DOI: 10.1016/j.canlet.2008.03.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 02/27/2008] [Accepted: 03/03/2008] [Indexed: 01/01/2023]
Abstract
Little attention has been paid to the role of adherens junctions (AJs) in acidic extracellular pH (pHe)-induced cell invasion. Incubation of HepG2 cells in acidic medium (pH 6.6) induced cell dispersion from tight cell clusters, and this change was accompanied by downregulation of beta-catenin at cell junctions and a rapid activation of c-Src. Pretreatment with PP2 prevented the acidic pH-induced downregulation of beta-catenin at AJ and in the membrane fractions. The acidic pHe-induced c-Src activation increased tyrosine phosphorylation of beta-catenin and decreased the amount of beta-catenin-associated E-cadherin. The depletion of membrane-bound beta-catenin coincided with enhanced cell migration and invasion, and this acidic pHe-increased cell migration and invasion was prevented by PP2. In conclusion, this study characterizes a novel signaling pathway responsible for acidic microenvironment-promoted migration and invasive behaviors of cancer cells.
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Affiliation(s)
- Kuo-Hsin Chen
- Far Eastern Memorial Hospital, Department of Surgery and Division of General Surgery, Taipei 220, Taiwan
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Huang SH, Chen Y, Tung PY, Wu JC, Chen KH, Wu JM, Wang SM. Mechanisms for the magnolol-induced cell death of CGTH W-2 thyroid carcinoma cells. J Cell Biochem 2007; 101:1011-22. [PMID: 17390340 DOI: 10.1002/jcb.21100] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Magnolol, a substance purified from the bark of Magnolia officialis, inhibits cell proliferation and induces apoptosis in a variety of cancer cells. The aim of this study was to study the effects of magnolol on CGTH W-2 thyroid carcinoma cells. After 24 h treatment with 80 microM magnolol in serum-containing medium, about 50% of the cells exhibited apoptotic features and 20% necrotic features. Cytochrome-c staining was diffused in the cytoplasm of the apoptotic cells, but restricted to the mitochondria in control cells. Western blot analyses showed an increase in levels of activated caspases (caspase-3 and -7) and of cleaved poly (ADP-ribose) polymerase (PARP) by magnolol. Concomitantly, immunostaining for apoptosis inducing factor (AIF) showed a time-dependent translocation from the mitochondria to the nucleus. Inhibition of either PARP or caspase activity blocked magnolol-induced apoptosis, supporting the involvement of the caspases and PARP. In addition, magnolol activated phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and inactivated Akt by decreasing levels of phosphorylated PTEN and phosphorylated Akt. These data suggest that magnolol promoted apoptosis probably by alleviating the inhibitory effect of Akt on caspase 9. Furthermore, inhibition of PARP activity, but not of caspase activity, completely prevented magnolol-induced necrosis, suggesting the notion that it might be caused by depletion of intracellular ATP levels due to PARP activation. These results show that magnolol initiates apoptosis via the cytochrome-c/caspase 3/PARP/AIF and PTEN/Akt/caspase 9/PARP pathways and necrosis via PARP activation.
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Affiliation(s)
- Shih-Horng Huang
- Department of Surgery and Division of General Surgery, Far Eastern Memorial Hospital, Taipei, Taiwan
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Yang SH, Chen YJ, Tung PY, Lai WL, Chen Y, Jeng CJ, Wang SM. Anti-Thy-1 antibody-induced neurite outgrowth in cultured dorsal root ganglionic neurons is mediated by the c-Src-MEK signaling pathway. J Cell Biochem 2007; 103:67-77. [PMID: 17486586 DOI: 10.1002/jcb.21387] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Our previous study has shown that anti-Thy-1 antibody promotes neurite outgrowth of cultured dorsal root ganglion (DRG) neurons in a protein kinase A (PKA)-dependent manner. The present study provided another intracellular signaling pathway for the neurotrophic effect of anti-Thy-1 antibody. In DMSO-treated control cells, Thy-1 was enriched in microdomain-like structures on cell membranes by immunofluorescence observation. Treatment of DRG neurons with anti-Thy-1 antibody not only stimulated neurite outgrowth, but also increased the branching complexity of the neurites in both small and large neurons. We have previously shown that anti-Thy-1 antibody causes a time-dependent activation of mitogen-activated protein kinase (MEK) and of cyclic AMP response-element binding protein (CREB). Here, anti-Thy-1 antibody elicited a transient activation of c-Src kinase, and the activation of c-Src kinase appeared occurring upstream of the activation of MEK and CREB, since pretreatment with the Src kinase inhibitor, PP2, effectively abolished the anti-Thy-1 antibody-induced neurite outgrowth and the phosphorylation of MEK and CREB. CREB phosphorylation might result in upregulation of certain neurite outgrowth-related proteins. We therefore conclude that anti-Thy-1 antibody activates the c-Src kinase-MEK-CREB cascade and overcomes the inhibitory effect of Thy-1 on neurite outgrowth in DRG neurons.
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Affiliation(s)
- Shih-Hung Yang
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
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Chen CH, Chen YJ, Jeng CJ, Yang SH, Tung PY, Wang SM. Role of PKA in the anti-Thy-1 antibody-induced neurite outgrowth of dorsal root ganglionic neurons. J Cell Biochem 2007; 101:566-75. [PMID: 17177293 DOI: 10.1002/jcb.21217] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Thy-1 is highly expressed in the mammalian nervous system. Our previous study showed that addition of anti-Thy-1 antibody to cultured dorsal root ganglionic (DRG) neurons promotes neurite outgrowth. In this study, we identified a novel signaling pathway mediating this event. Treatment with function-blocking anti-Thy-1 antibodies enhanced neurite outgrowth of DRG neurons in terms of total neurite length, longest neurite length, and total neurite branching points. To elucidate the possible signal transduction pathway involved, activation of kinases was evaluated by Western blotting. Transient phosphorylation of protein kinase A (PKA) and mitogen-activated kinase kinase (MEK) was induced after 15 min of anti-Thy-1 antibody treatment. Pretreatment with a PKA inhibitor (PKI) or an MEK inhibitor, PD98059, significantly decreased the neurite outgrowth response triggered by anti-Thy-1 antibody, indicating the involvement of both kinases. In addition, anti-Thy-1 antibody treatment also induced transient phosphorylation of cyclic AMP-response element-binding protein (CREB) and this effect was also blocked by a PKI or PD98059. Furthermore, the fact that PKI abolished anti-Thy-1 antibody-induced MEK phosphorylation showed that PKA acts upstream of the MEK-CREB cascade. In summary, the PKA-MEK-CREB pathway is a new pathway involved in the neurite outgrowth-promoting effect of anti-Thy-1 antibody.
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Affiliation(s)
- Chien-Hsing Chen
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Yung PS, Lai YM, Tung PY, Tsui HT, Wong CK, Hung VWY, Qin L. Effects of weight bearing and non-weight bearing exercises on bone properties using calcaneal quantitative ultrasound. Br J Sports Med 2005; 39:547-51. [PMID: 16046341 PMCID: PMC1725287 DOI: 10.1136/bjsm.2004.014621] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE This study was designed to investigate bone properties using heel quantitative ultrasound (QUS) in young adults participating in various sports. METHODS A cross sectional study was performed on Chinese male students (n = 55), aged 18-22 years. Subjects with previous fractures or suffering from any diseases known to affect bone metabolism or taking any medication with such an effect, were not included. The subjects were categorised according to their main sporting activities, including soccer (n = 15) (a high impact, weight bearing exercise), dancing (n = 10) (a low impact, weight bearing exercise), and swimming (n = 15) (non-weight bearing exercise). A sedentary group acted as controls (n = 15). A reproducibility study of the velocity of sound (VOS) and the broadband ultrasound attenuation (BUA) measurement was performed and analysed using the intraclass correlation coefficient (ICC). RESULTS There was good intra-investigator and inter-investigator agreement (ICC > or = 0.8; p < 0.05) in the measurement of BUA and VOS. No significant differences in BUA and VOS (p > 0.05) were found between the dominant and non-dominant heel. Soccer players (137 +/- 4.3 dB/MHz; 1575 +/- 56 m/s; 544.1 +/- 48.4) and dancers (134.6 +/- 3.7 dB/MHz; 1538 +/- 46 m/s; 503.0 +/- 37.0) had significantly higher BUA, VOS, and stiffness index (SI) scores (p < 0.05), respectively, than swimmers (124.1 +/- 5.1 dB/MHz; 1495 +/- 42 m/s; 423.3 +/- 46.9) and the sedentary control group (119.9 +/- 6.1 dB/MHz; 1452 +/- 41 m/s; 369.9 +/- 46.4). A trend of a significant linear increase with the weight bearing and high impact exercise was revealed in all QUS parameters (p < 0.05). CONCLUSION This cross sectional study indicated that regular participation in weight bearing exercise in young people might be beneficial for accruing peak bone mass and optimising bone structure.
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Affiliation(s)
- P S Yung
- Department of Optometry and Radiography, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
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Lyznik LA, McGee JD, Tung PY, Bennetzen JL, Hodges TK. Homologous recombination between plasmid DNA molecules in maize protoplasts. Mol Gen Genet 1991; 230:209-18. [PMID: 1745230 DOI: 10.1007/bf00290670] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The requirements for homologous recombination between plasmid DNA molecules have been studied using the PEG (polyethylene glycol)-mediated transformation system of maize (Zea mays L.) protoplasts coupled with the transient expression assay for beta-glucuronidase (GUS). Two plasmids were introduced into maize protoplasts; one plasmid (pB x 26) contained a genomic clone of the Adh1 maize gene; the other plasmid (piGUS) was a promoterless construction containing part of intron A of the Adh1 gene fused to the gusA coding sequence. Thus, the two vectors shared an effective homologous region consisting of a 459 bp (HindIII-PvuII) fragment of the Adh1 intron A sequence. An active gusA fusion gene would result upon homologous recombination between the plasmids within the intron A sequence, and indeed GUS activity was observed in extracts following co-transformation of maize protoplasts with the two plasmids. The presence of recombinant DNA molecules in protoplast DNA isolated 1 day after co-transformation was verified using polymerase chain reactions (PCR) and Southern blots. For efficient homologous recombination, both plasmids had to be linearized. The recombination reaction was induced by restriction of the plasmid molecules either inside the effective homologous region or at the borders of the intron sequence. However, the presence of even small, terminal, nonhomologous sequences at the 3' end of the pB x 26 fragment inhibited the recombination reaction. Also, both ends of the linearized piGUS DNA molecules were involved in the recombination reaction. The results revealed some features of homologous recombination reactions occurring in plant cells which cannot be accommodated by mechanisms postulated for similar reactions in animal system and in lower eukaryotes.
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Affiliation(s)
- L A Lyznik
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
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