Publications by authors named "Chung-Shi Yang"

101 Publications

Hericium erinaceus mycelium and its small bioactive compounds promote oligodendrocyte maturation with an increase in myelin basic protein.

Sci Rep 2021 Mar 22;11(1):6551. Epub 2021 Mar 22.

Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, #1 University Road, Tainan, Taiwan.

Oligodendrocytes (OLs), myelin-producing glia in the central nervous system (CNS), produce a myelin extension that enwraps axons to facilitate action potential propagation. An effective approach to induce oligodendrogenesis and myelination is important to foster CNS development and promote myelin repair in neurological diseases. Hericium (H.) erinaceus, an edible and culinary-medicinal mushroom, has been characterized as having neuroprotective activities. However, its effect on OL differentiation has not yet been uncovered. In this study using oligodendrocyte precursor cell (OPC) cultures and an ex vivo cerebellar slice system, we found that the extract from H. erinaceus mycelium (HEM) not only promoted the differentiation of OPCs to OLs in the differentiation medium, but also increased the level of myelin basic protein (MBP) on neuronal fibers. Moreover, daily oral administration of HEM into neonatal rat pups for 7 days enhanced MBP expression and OLs in the corpus callosum of the postnatal rat brain. The effect of HEM-derived bioactive compounds, the diterpenoid xylosides erinacine A (HeA) and HeC and a sesterterpene with 5 isoprene units called HeS, were further evaluated. The results showed that HeA and HeS more potently stimulated MBP expression in OLs and increased the number of OLs. Moreover, overlap between MBP immunoreactivity and neuronal fibers in cultured cerebellar tissue slices was significantly increased in the presence of HeA and HeS. In summary, our findings indicate that HEM extract and its ingredients HeA and HeS display promising functional effects and promote OL maturation, providing insights into their potential for myelination in neurodevelopmental disorders.
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http://dx.doi.org/10.1038/s41598-021-85972-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7985201PMC
March 2021

Differentiation of Tumorigenic C6 Glioma Cells Induced by Enhanced IL-6 Signaling.

Medicina (Kaunas) 2020 Nov 19;56(11). Epub 2020 Nov 19.

Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan.

: Cancer stem cells (CSCs) are obstacles to cancer therapy due to their therapeutic resistance, ability to initiate neoplasia, and roles in tumor relapse and metastasis. Efforts have been made to cure CSCs, such as the use of differentiation therapy, which induces cancer stem-like cells to undergo differentiation and decrease their tumorigenicity. Interleukin 6 (IL-6) upregulates the expression of glial fibrillary acidic protein (GFAP) in C6 glioma cells, indicating that it is able to induce the differentiation of these cells. The C6 glioma cell line forms a high percentage of cancer stem-like cells, leading us to speculate whether IL-6 signaling could modulate the differentiation of tumorigenic C6 glioma cells. However, we observed that IL-6 alone could not efficiently induce the differentiation of these cells. Therefore, different IL-6 signaling elicitors, including IL-6 alone, a combination of IL-6 and soluble IL-6 receptor (IL-6/sIL-6R), and tumor necrosis factor-α (TNF-α) plus IL-6/sIL-6R (TNF-α/IL-6/sIL-6R), were evaluated for their potential use in differentiation therapy. : The potential of IL-6 signaling elicitors in differentiation therapy were examined by assessing changes in biomarker levels, the rate of cell proliferation, and tumorigenicity, respectively. : Enhanced IL-6 signaling could effectively induce C6 glioma cell differentiation, as determined by observed variations in the expression of differentiation, cell cycle, and stem cell biomarkers. Additionally, the total cell population and the tumorigenicity of glioma cells were all considerably reduced after TNF-α/IL-6/sIL-6R treatment. : Our findings provide evidence that enhanced IL-6 signaling can efficiently promote tumorigenic C6 glioma cells to undergo differentiation.
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http://dx.doi.org/10.3390/medicina56110625DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7699282PMC
November 2020

Assessment of Polyethylene Glycol-Coated Gold Nanoparticle Toxicity and Inflammation In Vivo Using NF-κB Reporter Mice.

Int J Mol Sci 2020 Oct 31;21(21). Epub 2020 Oct 31.

Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan.

Polyethylene glycol (PEG) coating of gold nanoparticles (AuNPs) improves AuNP distribution via blood circulation. The use of PEG-coated AuNPs was shown to result in acute injuries to the liver, kidney, and spleen, but long-term toxicity has not been well studied. In this study, we investigated reporter induction for up to 90 days in NF-κB transgenic reporter mice following intravenous injection of PEG-coated AuNPs. The results of different doses (1 and 4 μg AuNPs per gram of body weight), particle sizes (13 nm and 30 nm), and PEG surfaces (methoxyl- or carboxymethyl-PEG 5 kDa) were compared. The data showed up to 7-fold NF-κB reporter induction in mouse liver from 3 h to 7 d post PEG-AuNP injection compared to saline-injected control mice, and gradual reduction to a level similar to control by 90 days. Agglomerates of PEG-AuNPs were detected in liver Kupffer cells, but neither gross pathological abnormality in liver sections nor increased activity of liver enzymes were found at 90 days. Injection of PEG-AuNPs led to an increase in collagen in liver sections and elevated total serum cholesterol, although still within the normal range, suggesting that inflammation resulted in mild fibrosis and affected hepatic function. Administrating PEG-AuNPs inevitably results in nanoparticles entrapped in the liver; thus, further investigation is required to fully assess the long-term impacts by PEG-AuNPs on liver health.
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http://dx.doi.org/10.3390/ijms21218158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7662512PMC
October 2020

Chronic exposure to high fat diet triggers myelin disruption and interleukin-33 upregulation in hypothalamus.

BMC Neurosci 2019 07 10;20(1):33. Epub 2019 Jul 10.

Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.

Background: Hypothalamic inflammation including astrogliosis and microglia activation occurs after intake of high fat diet (HFD) in rodent models or in obese individuals. However, the effect of chronic HFD feeding on oligodendrocytes (OLGs), a myelin-producing glial population in the central nervous system (CNS), remains unclear. In this study, we used 8-week old male C57BL/6 mice fed by HFD for 3-6 months to induce chronic obesity.

Results: The transmission electron microscopy imaging analysis showed that the integrity of hypothalamic myelin was disrupted after HFD feeding for 4 and 6 months. Moreover, the accumulation of Iba1-microglia with an amoeboid hypertrophic form was continually observed in arcuate nucleus of HFD-fed mice during the entire feeding time period. Interleukin-33 (IL-33), a tissue alarmin upon injury to the CNS, was detected with an increased level in hypothalamus after HFD feeding for 3 and 4 months. Furthermore, the in vitro study indicated that exposure of mature OLGs to IL-33 impaired OLG cell structure along with a decline in the expression of myelin basic protein.

Conclusions: Altogether, our findings demonstrate that chronic HFD feeding triggers hypothalamic myelin disruption in accompany with IL-33 upregulation and prolonged microglial activation in hypothalamus. Given that the addition of exogenous IL-33 was harmful for the maturation of OLGs, an increase in IL-33 by chronic HFD feeding might contribute to the induction of hypothalamic myelin disruption.
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http://dx.doi.org/10.1186/s12868-019-0516-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6617565PMC
July 2019

NanoCsA improves the survival of human iPSC transplant in hemiparkinsonian rats.

Brain Res 2019 09 30;1719:124-132. Epub 2019 May 30.

Center for Neuropsychiatric Research, National Health Research Institutes, Zhunan, Taiwan. Electronic address:

Increasing evidence has supported that transplantation of human stem cells induces neuroprotective and reparative effects in animal models of Parkinson's disease (PD). However, without systemic immunosuppressive therapy, most of these grafted cells are rejected by the hosts. Long term and systemic injection of cyclosporine-A (CsA) is required to maintain the survival of grafted cells. The purpose this study is to examine a new treatment strategy to suppress the immunorejection by locally co-grafting of polylactic/glycolic acid nanoparticles containing CsA (NanoCsA) with differentiated human induced pluripotent stem cells (iPSCs). In the in vitro media, NanoCsA provided sustained release of CsA for >6 weeks. The differentiated human iPSCs were co-grafted with NanoCsA or NanoVeh (nanoparticle without CsA) to the striatum of unilaterally 6-hydroxydopamine -lesioned rats. NanoCsA/iPSCs co-graft significantly improved locomotor activity compared to NanoVeh/iPSCs co-grafts or iPSC grafts + sytemic CsA at 1 month after transplantation. Brain tissues were collected for measurements of tyrosine hydroxylase (TH) and human marker Stem121 immunoreactivity. Cografting with NanoCsA/iPSCs, compared to NanoVeh/iPSCs, significantly increased TH and Stem121 immunoreactivity as well as tumor formation in the lesioned striatum. Taken together, our study supports that NanoCsA provides long-lasting CsA release and reduces immunorejection of human iPSCs xenograft in a 6-hydroxydopamine rat model of PD.
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http://dx.doi.org/10.1016/j.brainres.2019.05.040DOI Listing
September 2019

Effect of a Point Mutation in on Susceptibility to Daptomycin, Vancomycin, and Oxacillin in an MRSA Clinical Strain.

Front Microbiol 2018 25;9:1086. Epub 2018 May 25.

Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan, Taiwan.

We previously reported the sequential recovery of daptomycin-nonsusceptible MRSA clinical isolates with an L431F substitution in the MprF protein. The aim of the present study is to determine the effect of this mutation by replacing the gene on the chromosome of a daptomycin-susceptible progenitor strain, CGK5, to obtain CGK5mut having the L431F MprF mutation. Compared to CGK5, the daptomycin and vancomycin MICs of CGK5mut increased from 0.5 to 3 μg/ml and from 1.5 to 3 μg/ml, respectively; however, its oxacillin MIC decreased from 128 to 1 μg/ml in medium without added 2% NaCl. The expression levels of and several other cell-wall synthesis-related genes were significantly increased in CGK5mut, and the mutant also had significantly reduced negative cell membrane charge, thicker cell wall, and longer doubling time. These features were abolished in the reverse mutant carrying F431L MprF, confirming the pleiotropic effects of the L431F MprF mutation. We believe that this is the first work that shows a single MprF missense mutation can lead to not only changes in the cell membrane but also increased expression of and subsequently increased resistance to daptomycin and vancomycin while simultaneously conferring increased susceptibility to oxacillin in an isogenic MRSA strain.
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http://dx.doi.org/10.3389/fmicb.2018.01086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5980971PMC
May 2018

Function of B-Cell CLL/Lymphoma 11B in Glial Progenitor Proliferation and Oligodendrocyte Maturation.

Front Mol Neurosci 2018 24;11. Epub 2018 Jan 24.

Institute of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.

B-cell CLL/lymphoma 11B (Bcl11b) - a C2H2 zinc finger transcriptional factor - is known to regulate neuronal differentiation and function in the development of the central nervous system (CNS). Although its expression is reduced during oligodendrocyte (OLG) differentiation, its biological role in OLGs remains unknown. In this study, we found that the downregulation of Bcl11b gene expression in glial progenitor cells (GPCs) by lentivirus-mediated gene knockdown (KD) causes a reduction in cell proliferation with inhibited expression of stemness-related genes, while increasing the expression of cell cyclin regulator p21. In contrast, OLG specific transcription factors (Olig1) and OLG cell markers, including myelin proteolipid protein (PLP) and myelin oligodendrocyte glycoprotein (MOG), were upregulated in Bcl11b-KD GPCs. Chromatin immunoprecipitation (ChIP) analysis indicated that Bcl11b bound to the promoters of Olig1 and PLP, suggesting that Bcl11b could act as a repressor for Olig1 and PLP, similar to its action on p21. An increase in the number of GC- or PLP- OLGs derived from Bcl11b-KD GPCs or OLG precursor cells was also observed. Moreover, myelin basic protein (MBP) expression in OLGs derived from Bcl11b-KD GPCs was enhanced in hippocampal neuron co-cultures and in cerebellar brain-slice cultures. The study using a lysolecithin-induced demyelinating animal model also indicated that larger amounts of MBP-OLGs and PLP-OLGs derived from implanted Bcl11b-KD GPCs were present at the lesioned site of the white matter than in the scramble group. Taken together, our results provide insight into the functional role of Bcl11b in the negative regulation of GPC differentiation through the repression of OLG differentiation-associated genes.
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http://dx.doi.org/10.3389/fnmol.2018.00004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5787563PMC
January 2018

Reduction of CD200 expression in glioma cells enhances microglia activation and tumor growth.

J Neurosci Res 2016 12 15;94(12):1460-1471. Epub 2016 Sep 15.

Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.

CD200, a type I transmembrane glycoprotein, can interact with its receptor CD200R, which plays an inhibitory role in the activation of microglia-the resident macrophages of the central nervous system. In this study, the rat C6 glioma cell line (C6-1) that was previously characterized with high in vivo tumorigenicity was found to generate CD200 mRNA abundantly. However, CD200 expression was barely detected in another C6 glioma cell clone (C6-2) that was previously found to display low tumorigenic behavior. The results from CD200 immunohistochemistry on human glioma tissue array also showed that tumor cells in Grade I-II astrocytoma expressed a lower level of CD200 immunoreactivity than those detected in Grade III-IV glioblastoma multiforme. C6-1 transfectants with stable downregulation of CD200 gene expression using lentivirus knockdown approach were generated (C6-KD). Microglia and iNOS cells were increased when microglia were co-cultured with C6-KD cells. The colony formation of C6-KD was also augmented when those cells were co-cultured with microglia. Yet, increased colony formation of C6-KD transfectants in the co-culture with microglia was effectively suppressed by interleukin (IL)-4 and IL-10. The in vivo results indicated that the tumor formation of C6-1 cells in rat brain was promoted after CD200 gene knockdown. Moreover, CD11b activated microglia and iNOS microglia were highly accumulated in the tumor site formed by C6-KD. In conclusion, our findings demonstrate that the downregulation of CD200 expression in CD200-rich glioma cells could foster the formation of an activated microglia-associated tumor microenvironment, leading to glioma progression. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jnr.23922DOI Listing
December 2016

Stable water layers on solid surfaces.

Phys Chem Chem Phys 2016 Feb;18(8):5905-9

Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Sec. 2, Kuang-Fu Road Hsinchu, 30013, Taiwan.

Liquid layers adhered to solid surfaces and that are in equilibrium with the vapor phase are common in printing, coating, and washing processes as well as in alveoli in lungs and in stomata in leaves. For such a liquid layer in equilibrium with the vapor it faces, it has been generally believed that, aside from liquid lumps, only a very thin layer of the liquid, i.e., with a thickness of only a few nanometers, is held onto the surface of the solid, and that this adhesion is due to van der Waals forces. A similar layer of water can remain on the surface of a wall of a microchannel after evaporation of bulk water creates a void in the channel, but the thickness of such a water layer has not yet been well characterized. Herein we showed such a water layer adhered to a microchannel wall to be 100 to 170 nm thick and stable against surface tension. The water layer thickness was measured using electron energy loss spectroscopy (EELS), and the water layer structure was characterized by using a quantitative nanoparticle counting technique. This thickness was found for channel gap heights ranging from 1 to 5 μm. Once formed, the water layers in the microchannel, when sealed, were stable for at least one week without any special care. Our results indicate that the water layer forms naturally and is closely associated only with the surface to which it adheres. Our study of naturally formed, stable water layers may shed light on topics from gas exchange in alveoli in biology to the post-wet-process control in the semiconductor industry. We anticipate our report to be a starting point for more detailed research and understanding of the microfluidics, mechanisms and applications of gas-liquid-solid systems.
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http://dx.doi.org/10.1039/c5cp07866kDOI Listing
February 2016

Continuous affinity-gradient nano-stationary phase served as a column for reversed-phase electrochromatography and matrix carrier in time-of-flight mass spectrometry for protein analysis.

Anal Chim Acta 2015 Aug 10;889:166-71. Epub 2015 Aug 10.

Department of Engineering and System Science, National Tsing Hua University, 101, Section 2 Kuang Fu Road, Hsinchu 30013, Taiwan, ROC; Division of Mechanics, Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan, ROC. Electronic address:

This study developed an affinity-gradient nano-stationary phase (AG-NSP) for protein analysis using nanofluidic capillary electrochromatography (nano-CEC) conjugated with matrix assisted laser desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS). The AG-NSP can be used for protein pre-separation in nano-CEC and as a matrix carrier for protein analysis in MALDI-TOF-MS. A hydrophobicity gradient in AG-NSP was photochemically formed by grafting 4-azidoaniline hydrochloride on vertically arrayed multi-wall carbon nanotubes (MWCNTs) through gray-level exposure to UV light. The reversed-phase gradient stationary phase in AG-NSP was tailored according to the properties of the mobile phase gradient in capillary electrochromatography. As a result, the operation of the system is easily automated using a single buffer solution without the need for multiple solvents for elution. The use of nano-CEC with AG-NSP demonstrated excellent separation efficiency and high resolution for various types of DNA/protein/peptide. MALDI-TOF-MS analysis was then performed directly on the separated proteins and peptides on the chip. The proposed system was then used for the detection of three types of proteins with different molecular weights and PI values, including Cytochrome c (12,360, pI = 10), Lysozyme (14,300, pI = 11), and BSA (86,000, pI = 5)), and digested IgG fragments. The proposed system provided resolution of 1000 Da for the proteins in this study and the separation of digested IgG fragments at a low concentration of 1.2 pmol μL(-1).
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http://dx.doi.org/10.1016/j.aca.2015.07.034DOI Listing
August 2015

Depletion of B cell CLL/Lymphoma 11B Gene Expression Represses Glioma Cell Growth.

Mol Neurobiol 2016 08 23;53(6):3528-3539. Epub 2015 Jun 23.

Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.

B cell CLL/lymphoma 11B (Bcl11b), a C2H2 zinc finger transcription factor, not only serves as a critical regulator in development but also plays the controversial role in T cell acute lymphoblastic leukemia (T-ALL). We previously found that the enriched expression of Bcl11b was detected in high tumorigenic C6 glioma cells. However, the role of Bcl11b in glioma malignancy and its mechanisms remains to be uncovered. In this study, using the lentivirus-mediated knockdown (KD) approach, we found that Bcl11b KD in tumorigenic C6 cells reduced the cell proliferation, colony formation, and migratory ability. The results were further verified using two human malignant glioma cell lines, U87 and U251 cells. A cyclin-dependent kinase inhibitor p21, a known Bcl11b target, was significantly upregulated in tumorigenic C6, U87, and U251 cells after Bcl11b KD. Cellular senescence was observed by examination of the β-galactosidase activity in U87 and U251 cells with Bcl11b KD. Reduced expression of stemness gene Sox-2 and its downstream effector Bmi-1 was also observed in U87 and U251 cells with Bcl11b KD. These results suggest that the ablation of Bcl11b gene expression induced glioma cell senescence. Propidium iodide (PI) staining combined with flow cytometry analysis also showed that Bcl11b KD led to the cell cycle arrest of U87 and U251 cells at the G0/G1 or at the S phase, indicating that Bcl11b is required for glioma cell cycle progression. Together, this is the first study to show that the inhibition of Bcl11b suppresses glioma cell growth by regulating the expression of the cell cycle regulator p21 and stemness-associated genes (Sox-2/Bmi-1).
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http://dx.doi.org/10.1007/s12035-015-9231-1DOI Listing
August 2016

Ghrelin promotes renal cell carcinoma metastasis via Snail activation and is associated with poor prognosis.

J Pathol 2015 Sep 28;237(1):50-61. Epub 2015 May 28.

Genomics Research Centre, Academia Sinica, Taipei, Taiwan.

Ghrelin is an appetite-regulating molecule that promotes growth hormone (GH) release and food intake through growth hormone secretagogue receptor (GHS-R). Recently, high ghrelin levels have been detected in various types of human cancer. Ghrelin expression is observed in proximal and distal renal tubules, where renal cell carcinoma (RCC) arises. However, whether ghrelin is up-regulated and promotes renal cell carcinogenesis remains obscure. In this study, we observed that ghrelin was highly expressed in renal tumours, especially in metastatic RCC. In addition, high ghrelin levels correlated with poor outcome, lymph node and distant metastasis. The addition of ghrelin promoted the migration ability of RCC cell lines 786-0, ACHN and A-498. Furthermore, knockdown of ghrelin expression reduced in vitro migration and in vivo metastasis, suggesting a requirement for ghrelin accumulation in the microenvironment for RCC metastasis. Analysis of microarray signatures using Ingenuity Pathway Analysis (IPA) and MetaCore pointed to the potential regulation by ghrelin of Snail, a transcriptional repressor of E-cadherin. We further observed that Ghrelin increased the expression, nuclear translocation and promoter-binding activity of Snail. Snail silencing blocked the ghrelin-mediated effects on E-cadherin repression and cell migration. Snail-E-cadherin regulation was mediated by GHS-R-triggered Akt phosphorylation at Ser473 and Thr308. Pretreatment with PI3K inhibitors, LY294002 and wortmannin, as well as Akt siRNA, decreased ghrelin-induced Akt phosphorylation, Snail promoter binding activity and migration. Taken together, our findings indicate that ghrelin can activate Snail function via the GHS-R-PI3K-Akt axis, which may contribute to RCC metastasis. The microarray raw data were retrieved from the Cancer Genome Atlas (TCGA) [KIRC gene expression (IlluminaHiSeq) dataset].
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http://dx.doi.org/10.1002/path.4552DOI Listing
September 2015

Establishment of a trimodality analytical platform for tracing, imaging and quantification of gold nanoparticles in animals by radiotracer techniques.

Anal Chem 2015 Jan 11;87(1):601-8. Epub 2014 Dec 11.

Institute of Biomedical Engineering & Nanomedicine, National Health Research Institutes , Miaoli 35053, Taiwan.

This study aims to establish a (198)Au-radiotracer technique for in vivo tracing, rapid quantification, and ex vivo visualization of PEGylated gold nanoparticles (GNPs) in animals, organs and tissue dissections. The advantages of GNPs lie in its superior optical property, biocompatibility and versatile conjugation chemistry, which are promising to develop diagnostic probes and drug delivery systems. (198)Au is used as a radiotracer because it simultaneously emits beta and gamma radiations with proper energy and half-life; therefore, (198)Au can be used for bioanalytical purposes. The (198)Au-tagged radioactive gold nanoparticles ((198)Au-GNPs) were prepared simply by irradiating the GNPs in a nuclear reactor through the (197)Au(n,γ)(198)Au reaction and subsequently the (198)Au-GNPs were subjected to surface modification with polyethylene glycol to form PEGylated (198)Au-GNPs. The (198)Au-GNPs retained physicochemical properties that were the same as those of GNP before neutron irradiation. Pharmacokinetic and biodisposition studies were performed by intravenously injecting three types of (198)Au-GNPs with or without PEGylation into mice; the γ radiation in blood specimens and dissected organs was then measured. The (198)Au-radiotracer technique enables rapid quantification freed from tedious sample preparation and shows more than 95% recovery of injected GNPs. Clinical gamma scintigraphy was proved feasible to explore spatial- and temporal-resolved biodisposition of (198)Au-GNPs in living animals. Moreover, autoradiography, which recorded beta particles from (198)Au, enabled visualizing the heterogeneous biodisposition of (198)Au-GNPs in different microenvironments and tissues. In this study, the (198)Au-radiotracer technique facilitated creating a trimodality analytical platform for tracing, quantifying and imaging GNPs in animals.
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http://dx.doi.org/10.1021/ac503260fDOI Listing
January 2015

Downregulation of BRCA1-BRCA2-containing complex subunit 3 sensitizes glioma cells to temozolomide.

Oncotarget 2014 Nov;5(21):10901-15

Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan City, 70101, Taiwan.

We previously found that BRCA1-BRCA2-containing complex subunit 3 (BRCC3) was highly expressed in tumorigenic rat glioma cells. However, the functional role of BRCC3 in human glioma cells remains to be characterized. This study indicated that the upregulation of BRCC3 expression was induced in two human malignant glioblastoma U251 and A172 cell lines following exposure to the alkylating agent, temozolomide (TMZ). Homologous recombination (HR)-dependent DNA repair-associated genes (i.e. BRCA1, BRCA2, RAD51 and FANCD2) were also increased in U251 and A172 cells after treatment with TMZ. BRCC3 gene knockdown through lentivirus-mediated gene knockdown approach not only significantly reduced the clonogenic and migratory abilities of U251 and A172 cells, but also enhanced their sensitization to TMZ. The increase in phosphorylated H2AX foci (γH2AX) formation, an indicator of DNA damage, persisted in TMZ-treated glioma cells with stable knockdown BRCC3 expression, suggesting that BRCC3 gene deficiency is associated with DNA repair impairment. In summary, we demonstrate that by inducing DNA repair, BRCC3 renders glioma cells resistant to TMZ. The findings point to BRCC3 as a potential target for treatment of alkylating drug-resistant glioma.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4279418PMC
http://dx.doi.org/10.18632/oncotarget.2543DOI Listing
November 2014

Particulate nature of inhaled zinc oxide nanoparticles determines systemic effects and mechanisms of pulmonary inflammation in mice.

Nanotoxicology 2015 Feb 21;9(1):43-53. Epub 2014 Feb 21.

Center for Nanomedicine Research and.

Inhalation of zinc oxide nanoparticles (ZnONP) has potential health impact. Because zinc ion may involve in the toxicity of ZnONP, we compared adverse effects of inhaled aerosolized ZnONP and zinc nitrate in mice. Aerosolized ZnONP and zinc nitrate were well-dispersed in the inhalation chamber. Inhalation of 0.86 mg/m(3) ZnONP or 1.98 mg/m(3) zinc nitrate for 5 h caused acute inflammation mainly at bronchioloalveolar junctions of lungs at 24-h post-exposure. Inhalation of ZnONP or zinc nitrate increased metallothionein expression in the epithelial cells of brochioloalveolar junction. While the effects on cytokines secretion in bronchoalveolar lavage were similar between ZnONP and zinc nitrate, only ZnONP increased lactate dehydrogenase activity. However, repeated exposure to 0.86 mg/m(3) ZnONP 5 h/day for 5 days failed to cause a similar adverse effect. Either single or repeated exposure to 0.86 mg/m(3) ZnONP increased activities of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and creatine phosphokinase in blood. In contrast, exposure to zinc nitrate had no similar systemic effects. In human bronchial epithelial cells, ZnONP-induced interleukin-8 secretion was partially prevented by co-treatment with the Toll-like receptor 4 (TLR4) inhibitor. Furthermore, ZnONP-induced pulmonary inflammation was greater in wild-type mice than in TLR4-deficent mice. It appears that ZnONP-induced acute pulmonary inflammation partially depended on TLR4. In summary, we demonstrated the dose-responsive effects for inhalation of ZnONP and zinc nitrate in mice. The threshold of cytokines induction for inhalation of ZnONP for 5 h was 0.43 mg/m(3). The particulate characters of ZnONP might contribute to the systemic adverse effects and shall be evaluated for assessing its health impact in humans.
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http://dx.doi.org/10.3109/17435390.2014.886740DOI Listing
February 2015

Epstein-Barr virus BALF3 has nuclease activity and mediates mature virion production during the lytic cycle.

J Virol 2014 May 19;88(9):4962-75. Epub 2014 Feb 19.

Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan.

Unlabelled: Epstein-Barr virus (EBV) lytic replication involves complex processes, including DNA synthesis, DNA cleavage and packaging, and virion egress. These processes require many different lytic gene products, but the mechanisms of their actions remain unclear, especially for DNA cleavage and packaging. According to sequence homology analysis, EBV BALF3, encoded by the third leftward open reading frame of the BamHI-A fragment in the viral genome, is a homologue of herpes simplex virus type 1 UL28. This gene product is believed to possess the properties of a terminase, such as nucleolytic activity on newly synthesized viral DNA and translocation of unit length viral genomes into procapsids. In order to characterize EBV BALF3, the protein was produced by and purified from recombinant baculoviruses and examined in an enzymatic reaction in vitro, which determined that EBV BALF3 acts as an endonuclease and its activity is modulated by Mg(2+), Mn(2+), and ATP. Moreover, in EBV-positive epithelial cells, BALF3 was expressed and transported from the cytoplasm into the nucleus following induction of the lytic cycle, and gene silencing of BALF3 caused a reduction of DNA packaging and virion release. Interestingly, suppression of BALF3 expression also decreased the efficiency of DNA synthesis. On the basis of these results, we suggest that EBV BALF3 is involved simultaneously in DNA synthesis and packaging and is required for the production of mature virions.

Importance: Virus lytic replication is essential to produce infectious virions, which is responsible for virus survival and spread. This work shows that an uncharacterized gene product of the human herpesvirus Epstein-Barr virus (EBV), BALF3, is expressed during the lytic cycle. In addition, BALF3 mediates an endonucleolytic reaction and is involved in viral DNA synthesis and packaging, leading to influence on the production of mature virions. According to sequence homology and physical properties, the lytic gene product BALF3 is considered a terminase in EBV. These findings identify a novel viral gene with an important role in contributing to a better understanding of the EBV life cycle.
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http://dx.doi.org/10.1128/JVI.00063-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993834PMC
May 2014

Dysregulated interactions between lamin A and SUN1 induce abnormalities in the nuclear envelope and endoplasmic reticulum in progeric laminopathies.

J Cell Sci 2014 Apr 12;127(Pt 8):1792-804. Epub 2014 Feb 12.

Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Miaoli County 35053, Taiwan.

Hutchinson-Gilford progeria syndrome (HGPS) is a human progeroid disease caused by a point mutation on the LMNA gene. We reported previously that the accumulation of the nuclear envelope protein SUN1 contributes to HGPS nuclear aberrancies. However, the mechanism by which interactions between mutant lamin A (also known as progerin or LAΔ50) and SUN1 produce HGPS cellular phenotypes requires further elucidation. Using light and electron microscopy, this study demonstrated that SUN1 contributes to progerin-elicited structural changes in the nuclear envelope and the endoplasmic reticulum (ER) network. We further identified two domains through which full-length lamin A associates with SUN1, and determined that the farnesylated cysteine within the CaaX motif of lamin A has a stronger affinity for SUN1 than does the lamin A region containing amino acids 607 to 656. Farnesylation of progerin enhanced its interaction with SUN1 and reduced SUN1 mobility, thereby promoting the aberrant recruitment of progerin to the ER membrane during postmitotic assembly of the nuclear envelope, resulting in the accumulation of SUN1 over consecutive cellular divisions. These results indicate that the dysregulated interaction of SUN1 and progerin in the ER during nuclear envelope reformation determines the progression of HGPS.
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http://dx.doi.org/10.1242/jcs.139683DOI Listing
April 2014

Induced interleukin-33 expression enhances the tumorigenic activity of rat glioma cells.

Neuro Oncol 2014 Apr 9;16(4):552-66. Epub 2013 Dec 9.

Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan City, Taiwan (K.M.F., T.C.L., T.C.C., S.F.T.); Center for Nanomedicine Research, National Health Research Institutes, Zhunan, Taiwan (C.S.Y.).

Background: Glioma development is a multistep process associated with progressive genetic alterations but also regulated by cellular and noncellular components in a tumor-associated niche.

Methods: Using 2 rat C6 glioma cell clones with different tumorigenesis, named C6-1 and C6-2, this study characterized genes associated with enhanced tumorigenic features of glioma cells by comparative cDNA microarray analysis combined with Q-PCR. Neurospehere formation and clonogenicity were examined to determine the growth of tumorigenic C6 glioma cells. The lentivirus-mediated gene knockdown approach was conducted to determine the role of interleukin-33 (IL-33) in glioma cell proliferation and migration. Transwell cell invasion assay was used to examine microglia migration induced by tumorigenic C6 cells.

Results: The functional analysis of gene ontology (GO) biological processes shows that the upregulated genes found in tumorigenic C6 (C6-1) cells are closely related to cell proliferation. Tumorigenic C6 cells expressed cytokines and chemokines abundantly. Among these genes, IL-33 was profoundly induced in tumorigenic C6 cells with the expression of IL-33 receptor ST2. Furthermore, the growth rate and colony formation of tumorigenic C6 cells were attenuated by the inhibition of IL-33 and ST2 gene expression. Moreover, IL-33 was involved in tumorigenic glioma cell migration and regulation of the expression of several glioma-associated growth factors and chemokines in tumorigenic C6 cells.

Conclusion: Accordingly, we concluded that glioma cells with abundant production of IL-33 grow rapidly; moreover, the interactions of multiple cytokines/chemokines induced by glioma cells may develop a microenvironment that facilitates microglia/macrophage infiltration and fosters glioma growth in the brain.
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http://dx.doi.org/10.1093/neuonc/not234DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3956351PMC
April 2014

In-situ formation and assembly of gold nanoparticles by gum arabic as efficient photothermal agent for killing cancer cells.

Macromol Biosci 2013 Oct 16;13(10):1314-20. Epub 2013 Jul 16.

Center for Nanomedicine Research, Division of Medical Engineering Research, National Health Research Institutes, 35 Keyan Road, Zhunan, 35053, Taiwan.

Gold nanoparticles (AuNPs) have been established to sufficiently eradicate tumors by means of heat production for photothermal therapy. However, the translation of the AuNPs from bench to the clinic still remains to be solved until realizing high bioclearance after treatment. Herein, we developed a simple strategy for simultaneous formation and assembly of small-size gold nanoparticles (Au-SNPs) to form a novel nanocomposite in the presence of gum arabic (GA) by synchrotron X-ray irradiation in an aqueous solution within 5 min. GA, a porous polysaccharide, can not only provide a confined space in which to produce uniform Au-SNPs (1.6 ± 0.7 nm in diameter), but can also facilitate the formation of [email protected] (diameter ≈ 40 nm) after irradiating synchrotron X-rays. Specifically, the [email protected] possesses high thermal stability and a strong photothermal effect for killing cancer cells. Importantly, a bioclearance study demonstrated that the [email protected] can be gradually excreted by the renal and hepatobiliary system, which might be due to the breakdown and oxidation of GA under irradiating synchrotron X-rays. Thus, the novel gold nanocomposite can be promising photothermal agents for cancer treatment at the therapeutic level, minimizing toxicity concerns regarding long-term accumulation in vivo.
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http://dx.doi.org/10.1002/mabi.201300162DOI Listing
October 2013

Enhanced cell growth and tumorigenicity of rat glioma cells by stable expression of human CD133 through multiple molecular actions.

Glia 2013 Sep 6;61(9):1402-17. Epub 2013 Jul 6.

Institute of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.

CD133 (Prominin-1/AC133) is generally treated as a cell surface marker found on multipotent stem cells and tumor stem-like cells, and its biological function remains debated. Genetically modified rat glioma cell lines were generated by lentiviral gene delivery of human CD133 into rat C6 glioma cells (hCD133(+) -C6) or by infection of C6 cells with control lentivirus (mock-C6). Stable hCD133 expression promoted the self-renewal ability of C6-formed spheres with an increase in the expression of the stemness markers, Bmi-1 and SOX2. Akt phosphorylation, Notch-1 activation, and Notch-1 target gene expression (Hes-1, Hey1 and Hey2) were increased in hCD133(+) -C6 when compared to mock-C6. The inhibition of Akt phosphorylation, Notch-1 activation, and Hes-1 in hCD133(+) -C6 cells effectively suppressed their clonogenic ability, indicating that these factors are involved in expanding the growth of hCD133(+) -C6. An elevated expression of GTPase-activating protein 27 (Arhgap27) was detected in hCD133(+) -C6. A decline in the invasion of hCD133(+) -C6 by knockdown of Arhgap27 expression indicated the critical role of Arhgap27 in promoting cell migration of hCD133(+) -C6. In vivo study further showed that hCD133(+) -C6 formed aggressive tumors in vivo compared to mock-C6. Exposure of hCD133(+) -C6 to arsenic trioxide not only reduced Akt phosphorylation, Notch-1 activation and Hes-1 expression in vitro, but also inhibited their tumorigenicity in vivo. The results show that C6 glioma cells with stable hCD133 expression enhanced their stemness properties with increased Notch-1/Hes-1 signaling, Akt activation, and Arhgap27 action, which contribute to increased cell proliferation and migration of hCD133(+) -C6 in vitro, as well as progressive tumor formation in vivo.
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http://dx.doi.org/10.1002/glia.22521DOI Listing
September 2013

Cadmium-based quantum dot induced autophagy formation for cell survival via oxidative stress.

Chem Res Toxicol 2013 May 25;26(5):662-73. Epub 2013 Apr 25.

Division of Environmental Health and Occupational Medicine, National Health Research Institutes , Zhunan, Taiwan, Republic of China.

Quantum dots (QDs) are one of most utilized nanomaterials in nanocrystalline semiconductors. QDs emit near-infrared fluorescence and can be applied as probes for detecting vasculature and imaging in biological systems. Since QDs have potential in clinical application, the toxicity of QDs needs to be carefully evaluated. In our present study, we elucidate the cytotoxic mechanisms of QDs using a mouse renal adenocarcinoma (RAG) cell line. QDs in RAG cells increased intracellular reactive oxygen species (ROS) levels and induced autophagy at 6 h, leading to subsequent apoptosis at 24 h. QDs entered the cells and were located within the endoplasmic reticulum (ER), endosome, and lysosome at 6 h and endosome, lysosome, and mitochondria at 24 h. However, QDs only affected mitochondrial function and did not induce ER stress. N-Acetylcysteine, an antioxidant agent, reduced intracellular ROS levels and decreased QD-induced autophagy but enhanced QD-induced cell death. Moreover, 3-methylamphetamine (an autophagy inhibitor) also reduced the cell viability in QD-treated cells. These findings suggest that ROS plays an essential role in the regulation of QD-induced autophagy, which subsequently enhances cell survival. Taken together, these results suggest that oxidative stress-induced autophagy is a defense/survival mechanism against the cytotoxicity of QD.
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http://dx.doi.org/10.1021/tx300455kDOI Listing
May 2013

Quantum dots induced monocyte chemotactic protein-1 expression via MyD88-dependent Toll-like receptor signaling pathways in macrophages.

Toxicology 2013 Jun 15;308:1-9. Epub 2013 Mar 15.

Institute of NanoEngineering and Microsystems, National Tsing Hua University, Hsinchu, Taiwan, ROC.

Quantum dots (QDs) are nano-sized semiconductors. Previously, intratracheal instillation of QD705s induces persistent inflammation in mouse lungs. In our present study, QD705-COOH and QD705-PEG activated NF-κB and increased monocyte chemotactic protein-1 (MCP-1) expression in macrophages RAW264.7 via MyD88 dependent Toll-like receptor (TLR) signaling pathways. MyD88 is an adapter protein for most TLRs to activate NF-κB. Silencing expression of MyD88 or p65 with siRNA or co-treatment with a NF-κB inhibitor tremendously abolished QD705s-induced NF-κB activity and MCP-1 expression. The involved TLRs might locate either on the cell surface or inside of cells. Co-treatment with a TLR4 inhibitor completely prevented MCP-1 induction by QD705-PEG. Nevertheless, QD705-COOH readily entered cells, and co-treatment with either inhibitors of endocytosis or intracellular TLRs prevented MCP-1 induction. These findings indicate that, depending on their surface modification, OD705s activate MyD88 dependent-TLRs at the surface or inside of the cells, which is an important mechanism for nanoparticles-induced inflammatory responses. But other MyD88-independent pathways may also involve in these responses.
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http://dx.doi.org/10.1016/j.tox.2013.03.003DOI Listing
June 2013

Valproic acid attenuates microgliosis in injured spinal cord and purinergic P2X4 receptor expression in activated microglia.

J Neurosci Res 2013 May 13;91(5):694-705. Epub 2013 Feb 13.

Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan.

Peripheral injection with a high dose of valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, into animals with mild or moderate spinal cord injury (SCI) for 1 week can reduce spinal cord tissue loss and promote hindlimb locomotor recovery. A purinergic adenosine triphosphate (ATP) receptor subtype, P2X4 receptor (P2X4 R), has been considered as a potential target to diminish SCI-associated inflammatory responses. In this study, using a minipump-based infusion system, we found that intraspinal infusion with VPA for 3 days into injured spinal cord significantly improved hindlimb locomotion of rats with severe SCI induced by a 10-g NYU impactor dropping from the height of 50 mm onto the spinal T9/10 segment. The neuronal fibers in the injured spinal cord tissues were significantly preserved in VPA-treated rats compared with those observed in vehicle-treated animals. Moreover, the accumulation of microglia/macrophages and astrocytes in the injured spinal cord was attenuated in the animal group receiving VPA infusion. VPA also significantly reduced P2X4 R expression post-SCI. Furthermore, in vitro study indicated that VPA, but not the other HDAC inhibitors, sodium butyrate and trichostatin A (TSA), caused downregulation of P2X4 R in microglia activated with lipopolysaccharide (LPS). Moreover, p38 mitogen-activated protein kinase (MAPK)-triggered signaling was involved in the effect of VPA on the inhibition of P2X4 R gene expression. In addition to the findings from others, our results also provide important evidence to show the inhibitory effect of VPA on P2X4 R expression in activated microglia, which may contribute to reduction of SCI-induced gliosis and subsequently preservation of spinal cord tissues. © 2013 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jnr.23200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6322559PMC
May 2013

Charge-selective gate of arrayed MWCNTs for ultra high-efficient biomolecule enrichment by nano-electrostatic sieving (NES).

Biosens Bioelectron 2013 May 21;43:453-60. Epub 2012 Dec 21.

Department of Engineering and System Science, National Tsing Hua University, 101, Section 2 Kuang Fu Road, Hsinchu 30013, Taiwan ROC.

We report a rapid and highly-efficient biomolecule preconcentrating device based on nano-electrostatic sieving (NES) mechanism that is facilitated by multi-nanofluidic channels operated in parallel. The opening of these nanochannels is regulated by tunable charges that are generated on arrayed multi-walled carbon nanotubes (MWCNTs) gate. The NES device is fabricated by standard photolithography and plasma-enhanced chemical vapor deposition (PECVD) techniques, followed by subsequent deposition of parylene (poly(p-xylylene))-C on vertically grown MWCNTs in order to obtain arrayed multi-nanochannels with mean pore sizes that are comparable to the thickness of an electrical double layer (EDL). The enrichment efficiency for charged analytes is dependent on electrostatic repulsion, which is regulated by the distribution of the local electric field on the MWCNTs gate. The NES device exhibits polarity selectivity on the analytes and performs efficient collection and separation of biomolecules by probing the surface charge density dependence on the applied gate field. A tunable gate of the parylene-MWCNT nanochannels was used as size sieving devices for nano-scale biomolecules. The experimental results for the collection of FITC-labeled bovine serum albumin (BSA, 0.033nM) were as high as nearly 10(6) fold after only 45min. These data are attributed to the in-parallel molecule sieving process as conducted by the many nanochannels formed among the MWCNTs. This device allows uncharged polar molecules, such as water, to rapidly pass through thus enable highly efficient bio-molecule concentration for the application to ultra-high sensitive biosensing.
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http://dx.doi.org/10.1016/j.bios.2012.12.013DOI Listing
May 2013

Involvement of MyD88 in zinc oxide nanoparticle-induced lung inflammation.

Exp Toxicol Pathol 2013 Sep 24;65(6):887-96. Epub 2013 Jan 24.

Department of Pathology, School of Medicine, China Medical University, Taichung, Taiwan, ROC.

Zinc oxide nanoparticles (ZnONP) have great potential for medical applications. However, ZnONP is reported to induce acute lung inflammation, which limits its application in humans. We designed in vivo and in vitro studies to clarify ZnONP inflammation and its associated molecular signals. ZnONP with a single dose of 80 μg/30 μl was instilled into the tracheas of mice sacrificed at days 2, 7, 14, and 28 after instillation. Bronchoalveolar lavage fluid showed increased neutrophils and macrophages after treatment. Lung pathology showed a mixed inflammatory infiltrate of neutrophils, lymphocytes, and macrophages primarily in the bronchioles and peribronchiolar areas. Proinflammatory gene expression of TNF-α, IL-6, CXCL1, and MCP-1 was increased at day 2 and decreased after 7 days. The lung pathology resolved at day 28, without fibrosis. It remains unclear whether this acute lung inflammation was caused by ZnONP themselves or Zn(2+) iron released from the nanoparticles. In vitro studies confirming the results of in vivo studies showed increased expression of proinflammatory genes in both MLE12 cells (mouse lung epithelial cells) and RAW264.7 cells (mouse macrophages) with either ZnONP or Zn(NO₃)₂ treatment; notably, increased levels of proinflammatory genes were obviously higher in cells treated with ZnONP than in cells treated with Zn(NO₃)₂ at the same molarity dose. TNF-α and MCP-1 were induced only in MLE12 cells. MyD88, an adaptor protein for most Toll-like receptors (TLR) signaling pathways, initiated the ZnONP or Zn(NO₃)₂-induced lung inflammation. Silencing MyD88 expression with siRNA significantly reduced ZnONP or Zn(NO₃)₂-induced proinflammatory gene expression in MLE12 and RAW264.7 cells. Single-dose exposure to ZnONP produced the short-term lung inflammation via a MyD88-dependent TLR pathway. These data suggest that although both ZnONP and zinc ion might participate in the inflammatory reactions, ZnONP more effectively induced MyD88-dependent proinflammatory cytokines than zinc ion in lung epithelial cells.
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http://dx.doi.org/10.1016/j.etp.2013.01.001DOI Listing
September 2013

Programmable cellular retention of nanoparticles by replacing the synergistic anion of transferrin.

ACS Nano 2013 Jan 10;7(1):365-75. Epub 2012 Dec 10.

Biochemistry Laboratory, Department of Applied Chemistry, National Chi Nan University, Puli, Nantou 54561, Taiwan.

The ability to program the intracellular retention of nanoparticles (NPs) would increase their applicability for imaging and therapeutic applications. To date, there has been no efficient method developed to control the fate of NPs once they enter cells. Existing approaches to manipulate the intracellular retention of NPs are mostly "passive" and particle size-dependent. Different sized particles hold distinct cellular responses. The adverse effect of particle size may limit the utility of nanodelivery systems. Therefore, the development of tunable/"active" NP intracellular retention systems with fixed particle sizes remains a considerable challenge. By replacing the synergistic anions of transferrin (Tf) immobilized on quantum dots (Tf-QDs, ca. 25 nm), we have examined the feasibility of this concept. Substitution of synergistic anions of Tf from carbonate (holo-Tf) to oxalate (oxa-Tf) significantly increased the intracellular accumulation of the oxa-Tf-QDs as a result of (i) a delay in cellular removal triggered by oxalate (oxa-Tf)-induced endosomal Tf iron-release retardation and (ii) enhanced recycling of Tf-QD/TfR (Tf receptor) complexes from early endosomes to the plasma membrane. This accumulation extended the intracellular NP retention interval. The half-maximum fluorescence intensity of the oxa-Tf-QDs in vivo was 4 times higher than that of the holo-Tf-QDs. Programming of the intracellular NP retention time was accomplished through manipulation of the ratio of holo- and oxa-Tfs on the surfaces of the QDs. Using this simple and efficient approach, it was possible to readily achieve a desirable intracellular retention interval for the NPs.
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http://dx.doi.org/10.1021/nn3043397DOI Listing
January 2013

Versatile RBC-derived vesicles as nanoparticle vector of photosensitizers for photodynamic therapy.

Nanoscale 2013 Jan 27;5(1):416-21. Epub 2012 Nov 27.

Center for Nanomedicine Research, National Health Research Institutes, Miaoli, Taiwan.

Various nanocarriers for photosensitizers have been developed to solve the problems of limiting the clinical utility of photodynamic therapy (PDT); however, to date, no carriers capable of supplying oxygen have been reported. We reported the development of a novel system composed of red blood cell (RBC)-derived vesicles (RDVs) generated by osmotic stress and demonstrated the capacity of RDVs for encapsulating and delivering external cargo into targeted cells due to the cellular uptake of RDVs. In this study, protoporphyrin IX (PpIX)-encapsulated RDVs ([email protected]) were prepared by the hypotonic incorporation of PpIX into RDVs in an aqueous environment, characterized, and utilized for PDT of cancer. [email protected] were rapidly uptaken by tumor cells via endocytosis in vitro, and the highly phototoxic effect of [email protected] was demonstrated upon irradiation. Superoxide anion (O(2)˙) and singlet oxygen ((1)O(2)) were involved in [email protected] cell apoptosis and necrosis. Finally, we demonstrated that RDVs with an oxygen supply capacity have potential as versatile delivery vehicles for efficient PDT.
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http://dx.doi.org/10.1039/c2nr32506cDOI Listing
January 2013

Nanocapillary electrophoretic electrochemical chip: towards analysis of biochemicals released by single cells.

Interface Focus 2011 Oct 14;1(5):744-53. Epub 2011 Jul 14.

Department of Engineering and Systems Science , National Tsing Hua University , 101 Section 2 Kuang Fu Road, Hsinchu 300, Taiwan , Republic of China ; National Health Research Institutes , 35 Keyan Road, Zhunan, Miaoli 350, Taiwan , Republic of China.

A novel nanocapillary electrophoretic electrochemical (Nano-CEEC) chip has been developed to demonstrate the possibility of zeptomole-level detection of neurotransmitters released from single living cells. The chip integrates three subunits to collect and concentrate scarce neurotransmitters released from single PC-12 cells, including a pair of targeting electrodes for single cells captured by controlling the surface charge density; a dual-asymmetry electrokinetic flow device for sample collection, pre-concentration and separation in a nanochannel; and an online electrochemical detector for zeptomole-level sample detection. This Nano-CEEC chip integrates a polydimethylsiloxane microchannel for cell sampling and biomolecule separation and a silicon dioxide nanochannel for sample pre-concentration and amperometric detection. The cell-capture voltage ranges from 0.1 to 1.5 V with a frequency of 1-10 kHz for PC-12 cells, and the single cell-capture efficiency is optimized by varying the duration of the applied field. All of the processes, from cell sampling to neurotransmitter detection, can be completed within 15 min. Catecholamines, including dopamine and norepinephrine (noradrenaline) released from coupled single cells, have been successfully detected using the Nano-CEEC chip. A detection limit of 30-75 zeptomoles was achieved, which is close to the levels released by a single neuron in vitro.
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http://dx.doi.org/10.1098/rsfs.2011.0049DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262288PMC
October 2011

Electronic microscopy evidence for mitochondria as targets for Cd/Se/Te-based quantum dot 705 toxicity in vivo.

Kaohsiung J Med Sci 2012 Jul 4;28(7 Suppl):S53-62. Epub 2012 Jul 4.

Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Taiwan.

The safety of quantum dots (QDs) 705 was evaluated in this study. Mice were treated with QD705 (intravenous) at a single dose of (40 pmol) for 4, 12, 16, and 24 weeks. Effects of QD705 on kidneys were examined. While there was a lack of histopathology, reduction in renal functions was detected at 16 weeks. Electron microscopic examination revealed alterations in proximal convoluted tubule (PCT) cell mitochondria at even much earlier time, including disorientation and reduction of mitochondrial number (early change), mitochondrial swelling, and later compensatory mitochondrial hypertrophy (enlargement mitochondria: giant mitochondria with hyperplastic inner cristae) as well as mitochondrial hyperplasia (increase in mitochondrial biogenesis and numbers) were observed. Such changes probably represent compensatory attempts of the mitochondria for functional loss or reduction of mitochondria in QD705 treated animals. Moreover, degeneration of mitochondria (myelin-figure and cytoplasmic membranous body formation) and degradation of cytoplasmic materials (isolated cytoplasmic pockets of degenerated materials and focal cytoplasmic degradation) also occurred in later time points (16-24 weeks). Such mitochondrial changes were not identical with those induced by pure cadmium. Taken together, we suggest that mitochondria appeared to be the target of QD705 toxicity and specific mitochondrial markers may be useful parameters for toxicity assessments of QDs or other metal-based nanomaterials.
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http://dx.doi.org/10.1016/j.kjms.2012.05.011DOI Listing
July 2012
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