Publications by authors named "Apeng Chen"

19 Publications

  • Page 1 of 1

A multi-herb-combined remedy to overcome hyper-inflammatory response by reprogramming transcription factor profile and shaping monocyte subsets.

Pharmacol Res 2021 Apr 17;169:105617. Epub 2021 Apr 17.

Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Dongcheng District, Beijing 100700, China. Electronic address:

Traditional Chinese multi-herb-combined prescriptions usually show better performance than a single agent since a group of effective compounds interfere multiple disease-relevant targets simultaneously. Huang-Lian-Jie-Du decoction is a remedy made of four herbs that are widely used to treat oral ulcers, gingivitis, and periodontitis. However, the active ingredients and underlying mechanisms are not clear. To address these questions, we prepared a water extract solution of Huang-Lian-Jie-Du decoction (HLJDD), called it as WEH (Water Extract Solution of HLJDD), and used it to treat LPS-induced systemic inflammation in mice. We observed that WEH attenuated inflammatory responses including reducing production of cytokines, chemokines and interferons (IFNs), further attenuating emergency myelopoiesis, and preventing mice septic lethality. Upon LPS stimulation, mice pretreated with WEH increased circulating Ly6C patrolling and splenic Ly6C inflammatory monocytes. The acute myelopoiesis related transcriptional factor profile was rearranged by WEH. Mechanistically we confirmed that WEH interrupted LPS/TLR4/CD14 signaling-mediated downstream signaling pathways through its nine principal ingredients, which blocked LPS stimulated divergent signaling cascades, such as activation of NF-κB, p38 MAPK, and ERK1/2. We conclude that the old remedy blunts LPS-induced "danger" signal recognition and transduction process at multiple sites. To translate our findings into clinical applications, we refined the crude extract into a pure multicomponent drug by directly mixing these nine chemical entities, which completely reproduced the effect of protecting mice from lethal septic shock. Finally, we reduced a large number of compounds within a multi-herb water extract to seven-chemical combination that exhibited superior therapeutic efficacy compared with WEH.
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http://dx.doi.org/10.1016/j.phrs.2021.105617DOI Listing
April 2021

Liquid Chromatographic Separation Using a 2 μm i.d. Open Tubular Column at Elevated Temperature.

Anal Chem 2021 03 1;93(10):4361-4364. Epub 2021 Mar 1.

Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States.

We have experimentally demonstrated the extraordinarily high resolving power of liquid chromatography (LC) using a narrow open tubular (OT) column. In this work, we show that we can further increase its efficiency, peak capacity, and separation speed by elevating the operation (or column) temperature; all of these three numbers can be improved without mutual compromises. We use a mixture of five amino acids as a sample and show that we can increase the efficiency by 34%-260% and the separation speeds by 7%-10% by raising the operation temperature from 30 to 70 °C. When we use a 2 μm i.d. × 80 cm in length OT column coated with OTMS at a temperature of 70 °C, we can frequently obtain peak capacities of 700-800 within 20-30 min for separating cytochrome C digests. By increasing the column length to 160 cm, we can obtain a peak capacity of 2720 within 143 min for separating a complex peptide sample. This peak capacity is the highest peak capacity to date for one-dimensional LC separations. Importantly, heating the column is easy to implement and does not cost much, and many commercial LC systems already have compartments to control column temperatures. Running LC using a narrow OT column at an elevated temperature should broaden the applications of OT-LC in chemical and biochemical analyses.
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http://dx.doi.org/10.1021/acs.analchem.1c00296DOI Listing
March 2021

Performing flow injection chromatography using a narrow open tubular column.

Anal Chim Acta 2020 May 27;1109:19-26. Epub 2020 Feb 27.

Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA; Department of Chemistry, College of Sciences, Northeastern University, Shenyang, 110819, PR China. Electronic address:

Flow injection chromatography (FIC) or sequential injection chromatography (SIC) is a low-pressure liquid chromatography technique that uses flow injection or sequential injection hardware. Due to the constraints of this hardware, the separation resolution is low; often no more than 3-5 components are resolved. We have recently demonstrated the excellent resolving power of narrow open tubular (OT) columns for various biomolecules, and only moderate elution pressures are needed to carry out these separations. In this paper, we incorporate a narrow OT column with FIC and construct an FIC system using a pressure chamber and two injection valves to implement gradient elution. The resultant system not only improves the resolution but also reduces the system cost. When we use the system to separate peptides from trypsin-digested cytochrome C, we can resolve dozens of peptides (with resolutions of 0.5 or greater) at a speed of 12 samples per hour. When we use this system to separate a mixture containing 3 amino acids, we can base-line resolve these compounds at a speed of 1800 sample per hour.
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http://dx.doi.org/10.1016/j.aca.2020.02.052DOI Listing
May 2020

Terahertz switching between broadband absorption and narrowband absorption.

Opt Express 2020 Jan;28(2):2037-2044

A multilayer metamaterial with switchable functionalities is presented based on the phase-transition property of vanadium dioxide. When vanadium dioxide is in the metallic state, a broadband absorber is formed. Calculated results show that the combination of two absorption peaks enables absorptance more than 90% in the wide spectral range from 0.393 THz to 0.897 THz. Absorption performance is insensitive to polarization at the small incident angle and work well even at the larger incident angle. When vanadium dioxide is in the insulating state, the designed system behaves as a narrowband absorber at the frequency of 0.677 THz. This narrowband absorber shows the advantages of wide angle and polarization insensitivity due to the localized magnetic resonance. Furthermore, the influences of geometrical parameters on the performance of absorptance are discussed. The proposed switchable absorber can be used in various applications, such as selective heat emitter and solar photovoltaic field.
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http://dx.doi.org/10.1364/OE.376085DOI Listing
January 2020

Integrated metamaterial with functionalities of absorption and electromagnetically induced transparency.

Opt Express 2019 Sep;27(18):25196-25204

A switchable metamaterial with bifunctionality of absorption and electromagnetically induced transparency is proposed based on the phase-transition characteristic of phase change material-vanadium dioxide. When vanadium dioxide is in the metallic state, an isotropic narrow absorber is obtained in the terahertz region, which consists of a top metallic cross, a middle dielectric layer, and a bottom vanadium dioxide film. By adjusting structure parameters, perfect absorption is realized at the frequency of 0.498 THz. This designed narrow absorber is insensitive to polarization and incident angle. Absorptance can still reach 75% for transverse electric polarization and transverse magnetic polarization at the incident angle of 65. When vanadium dioxide is in the insulating state, the top metallic cross will interact with the bottom split ring resonator, and the interaction between them will lead to the appearance of electromagnetically induced transparency. The behavior of electromagnetically induced transparency works well for transverse electric polarization and transverse magnetic polarization at the small incident angle. The designed hybrid metamaterial opens possible avenues for achieving switchable functionalities in a single device.
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http://dx.doi.org/10.1364/OE.27.025196DOI Listing
September 2019

Experimentally Validating Open Tubular Liquid Chromatography for a Peak Capacity of 2000 in 3 h.

Anal Chem 2019 08 31;91(16):10518-10523. Epub 2019 Jul 31.

Department of Chemistry and Biochemistry , University of Oklahoma , Norman , Oklahoma 73019 , United States.

The advancements in life science research mandate effective tools capable of analyzing large numbers of samples with low quantities and high complexities. As an essential analytical tool for this research, liquid chromatography (LC) encounters an ever-increasing demand for enhanced resolving power, accelerated analysis speed, and reduced limit of detection. Although theoretical studies have indicated that open tubular (OT) columns can produce superior resolving power under comparable elution pressures and analysis times, ultrahigh-resolution and ultrahigh-speed open tubular liquid chromatography (OTLC) separations have never been reported. Here we present experimental results to demonstrate the predicted potential of this technique. We use a 2 μm i.d. × 75 cm long OT column coated with trimethoxy(octadecyl)silane for separating pepsin/trypsin digested lysates and routinely produce exceptionally high peak capacities (e.g., 1900-2000 in 3-5 h). We reduce the column length to 2.7 cm and exhibit the capability of OTLC for ultrafast separations. Under an elution pressure of 227.5 bar, we complete the separation of six amino acids in ∼800 ms and resolve these compounds within ∼400 ms. In addition, we show that OTLC has low attomole limits of detection (LOD) and each separation requires samples of only a few picoliters. Importantly, no ultrahigh elution pressures are required. With the ultrahigh resolution, ultrahigh speed, low LOD, and low sample volume requirement, OTLC can potentially be a powerful tool for biotech research, especially single cell analysis.
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http://dx.doi.org/10.1021/acs.analchem.9b01465DOI Listing
August 2019

Cam-based vibration-counter-balanced laser-induced fluorescence scanner for multiplexed capillary detection.

Talanta 2019 Jun 10;198:398-403. Epub 2019 Feb 10.

Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA. Electronic address:

Laser-induced fluorescence (LIF) rotary scanners have been successfully used for multiplexed capillary detection. However, these scanners have a limitation that the capillaries have to be assembled in a circular format, which can be inconvenient for certain applications. A linear LIF scanner works well for flat parallel capillary arrays, but motor accelerations/decelerations (for direction changes) and scanning head vibrations introduce high instrumental noises. The number of capillaries that can be scanned by a linear scanner is limited because of the above constraints. We have constructed a cam-based scanner in an attempt to address these issues. A cam-based scanner eliminates the motor accelerations/decelerations but not the scanning head vibrations. In this work, we attach a second scanning head to the cam on the opposite side of the first scanning head to counter-balance the mechanical vibrations. With this modification, we improve the limit of detection by more than 3 times (from 69 pM to 20 pM fluorescein). We also increase the capillary number capacity by more than 6 times; the total number of capillaries that can be scanned is 426 if 150-μm-o.d. capillaries are used or 320 if 200-μm-o.d. capillaries are used. To demonstrate the utility of this instrument, we assemble a 99-capillary array on one capillary holder and perform capillary electrophoresis of two fluorescent dyes; separations in all capillaries are successfully monitored simultaneously. We also apply it for detecting fluorescently labeled proteins resolved by 24 s-dimension capillaries in a chip-capillary hybrid device; two-dimensional separation results are nicely produced.
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http://dx.doi.org/10.1016/j.talanta.2019.01.128DOI Listing
June 2019

Immunohistochemistry analysis of Pygo2 expression in central nervous system tumors.

J Cell Commun Signal 2019 Mar 5;13(1):75-84. Epub 2018 Jul 5.

Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China.

Pygo2 as a Wnt signaling pathway component has been detected in multiple cancer types. In this study, we identified Pygo2 expression features by immunohistochemistry in 73 central nervous system tumor specimens, in comparison with 14 normal brain tissues and surrounding non-tumorous tissues of tumor. Our study indicated that 59% of the patient tumor specimens exhibited positive Pygo2-staining and increases intensity with the grade of malignancy, especially for WHO grade III and IV gliomas, was observed high level expression, compared with normal brain tissues. Five out of nine WHO grade III anaplastic astrocytomas and seven out of nine WHO grade IV glioblastomas showed Pygo2-positive staining. The analysis of Pygo2 gene expression by quantitative real-time PCR of additional ten fresh patient samples yielded similar results. Further studies performed with stable cell lines in vitro demonstrated that Pygo2 render cells higher proliferation rate, migration and anchorage-independent colony-forming ability in soft agar. Taken together, our studies suggest an important role of Pygo2 in brain tumor progression.
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http://dx.doi.org/10.1007/s12079-018-0476-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6381371PMC
March 2019

A preliminary origin-tracking study of different densities urinary exosomes.

Electrophoresis 2018 09 14;39(18):2316-2320. Epub 2018 Apr 14.

Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, P. R. China.

Based on density differences of different subpopulations of exosomes, two kinds of micro-vesicles with different densities were captured from urine by a modified sucrose density gradient ultracentrifuge separation method. Verified by transmission electron microscope (TEM) and western blot, the results showed these two kinds of micro-vesicles were all exosomes. And these two kinds of exosomes were analyzed by TEM, 2D electrophoresis (2DE), and capillary zone electrophoresis (CZE), respectively. The results of TEM showed these two exosomes with different densities have different morphological characteristics, and some tiny proteomic differences were shown in the results of 2DE of these two exosomes. At the same time, the CZE results displayed these two kinds of exosomes possessed different retention times, indicated that they may have different electrification property and particle weight. These results may attribute to their different origins. This work may provide a preliminary experience for the origin-tracking study for urinary exosomes, and would be more useful for future targeted biomarker discovery.
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http://dx.doi.org/10.1002/elps.201700388DOI Listing
September 2018

Two-dimensional liquid chromatography consisting of twelve second-dimension columns for comprehensive analysis of intact proteins.

Talanta 2018 May 1;182:225-229. Epub 2018 Feb 1.

Department of Chemistry and Biochemistry, University of Oklahoma, USA.

A comprehensive two-dimensional liquid chromatography (LCxLC) system consisting of twelve columns in the second dimension was developed for comprehensive analysis of intact proteins in complex biological samples. The system consisted of an ion-exchange column in the first dimension and the twelve reverse-phase columns in the second dimension; all thirteen columns were monolithic and prepared inside 250 µm i.d. capillaries. These columns were assembled together through the use of three valves and an innovative configuration. The effluent from the first dimension was continuously fractionated and sequentially transferred into the twelve second-dimension columns, while the second-dimension separations were carried out in a series of batches (six columns per batch). This LCxLC system was tested first using standard proteins followed by real-world samples from E. coli. Baseline separation was observed for eleven standard proteins and hundreds of peaks were observed for the real-world sample analysis. Two-dimensional liquid chromatography, often considered as an effective tool for mapping proteins, is seen as laborious and time-consuming when configured offline. Our online LCxLC system with increased second-dimension columns promises to provide a solution to overcome these hindrances.
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http://dx.doi.org/10.1016/j.talanta.2018.01.072DOI Listing
May 2018

Miniaturized high-performance liquid chromatography instrumentation.

Talanta 2018 Jan 14;177:94-103. Epub 2017 Sep 14.

Department of Chemistry and Biochemistry, University of Oklahoma, USA.

Miniaturized high performance liquid chromatography (HPLC) has attracted increasing attention for its potential in high-throughput analyses and point-of-care applications. In this review we highlight the recent advancements in HPLC system miniaturization. We focus on the major components that constitute these instruments along with their respective advantages and drawbacks as well as present a few representative miniaturized HPLC systems. We discuss briefly some of the applications and also anticipate the future development trends of these instrumental platforms.
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http://dx.doi.org/10.1016/j.talanta.2017.09.016DOI Listing
January 2018

Tunable Electroosmosis-Based Femto-Liter Pipette: A Promising Tool toward Living-Cell Surgery.

Anal Chem 2017 10 4;89(20):10806-10812. Epub 2017 Oct 4.

Department of Chemistry and Biochemistry, University of Oklahoma , Norman, Oklahoma 73019, United States.

Single-cell analysis has attracted increasing attention because of cell heterogeneities. Various strategies have been developed for analyzing single cells, but most of these analytical processes kill the cells. Tools that can qualitatively and quantitatively measure the cellular contents without killing the cell are highly demanding because they enable us to conduct single-cell time-course studies (e.g., to examine how a cell responds to a therapy before, during, and after a treatment). Here we develop a femto-liter (fL) pipet to serve this purpose. To ensure that we can accurately and precisely pipet fL solutions, we fill all conduits with liquid and use an electroosmotic pump (EOP) as the driving force to facilitate withdrawal of cellular contents from single cells. We tentatively term this device an EOP-driven pipette or EDP. We characterize the EDP for accurately and precisely withdrawing solution from ∼250 fL to 80 nL; a volume range that covers the applications for most types of cells. To demonstrate the feasibility of utilizing the EDP for a single-cell time-course study, we utilize the EDP to take the cellular contents out at different times during the course of a zebrafish embryo development for cholesterol measurements. More than 50% of the embryos survive after each pipetting and analysis step, and this number will increase considerably as we improve our cell manipulation skills and reduce the pipet-tip diameter. We expect this EDP to become an effective tool for single-cell time-course studies.
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http://dx.doi.org/10.1021/acs.analchem.7b02132DOI Listing
October 2017

High-performance liquid chromatographic cartridge with gradient elution capability coupled with UV absorbance detector and mass spectrometer for peptide and protein analysis.

J Sep Sci 2017 Jul 9;40(13):2752-2758. Epub 2017 Jun 9.

Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA.

We discuss the construction and performance of a high-performance liquid chromatography cartridge that we developed that resulted from a culmination of previous research. We have recently developed an innovative approach to creating gradient elutions using dual electroosmotic pumps and a series of three valves. This method has been proved to be the most reproducible and robust in producing gradients compared to our previously tested methods. Using this approach, we have assembled a high-performance liquid chromatography cartridge powered and controlled via a computer. We have successfully coupled the cartridge with an ultraviolet absorbance detector and a mass spectrometer for separating complex protein/peptide samples. The cartridge is readily coupled with other detectors such as electrochemical detector and laser-induced fluorescence detector.
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http://dx.doi.org/10.1002/jssc.201700185DOI Listing
July 2017

Monitoring gradient profile on-line in micro- and nano-high performance liquid chromatography using conductivity detection.

J Chromatogr A 2016 Aug 5;1460:68-73. Epub 2016 Jul 5.

Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, United States. Electronic address:

In micro- or nano-flow high performance liquid chromatography (HPLC), flow-splitters and gradient elutions are commonly used for reverse phase HPLC separations. When a flow splitter was used at a high split-ratio (e.g., 1000:1 or higher), the actual gradient may deviate away from the programmed gradient. Sometimes, mobile phase concentrations can deviate by as much as 5%. In this work, we noticed that the conductivity (σ) of a gradient decreased with the increasing organic-solvent fraction (φ). Based on the relationship between σ and φ, a method was developed for monitoring gradient profile on-line to record any deviations in these HPLC systems. The conductivity could be measured by a traditional conductivity detector or a capacitively coupled contactless conductivity detector (C(4)D). The method was applied for assessing the performance of an electroosmotic pump (EOP) based nano-HPLC. We also observed that σ value of the gradient changed with system pressure; a=0.0175ΔP (R(2)=0.964), where a is the percentage of the conductivity increase and ΔP is the system pressure in bar. This effect was also investigated.
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http://dx.doi.org/10.1016/j.chroma.2016.07.005DOI Listing
August 2016

Combining selection valve and mixing chamber for nanoflow gradient generation: Toward developing a liquid chromatography cartridge coupled with mass spectrometer for protein and peptide analysis.

Anal Chim Acta 2015 Aug 7;887:230-236. Epub 2015 Aug 7.

Department of Chemistry and Biochemistry, University of Oklahoma Norman, OK 73019, USA. Electronic address:

Toward developing a micro HPLC cartridge, we have recently built a high-pressure electroosmotic pump (EOP). However, we do not recommend people to use this pump to deliver an organic solvent directly, because it often makes the pump rate unstable. We have experimented several approaches to address this issue, but none of them are satisfactory. Here, we develop an innovative approach to address this issue. We first create an abruption (a dead-volume) within a fluid conduit. We then utilize an EOP to withdraw, via a selection valve, a train of eluent solutions having decreasing eluting power into the fluid conduit. When these solutions are further aspirated through the dead-volume, these solutions are partially mixed, smoothening concentration transitions between two adjacent eluent solutions. As these solutions are pushed back, through the dead-volume again, a smooth gradient profile is formed. In this work, we characterize this scheme for gradient formation, and we incorporate this approach with a high-pressure EOP, a nanoliter injection valve, and a capillary column, yielding a micro HPLC system. We then couple this micro HPLC with an electrospray ionization - mass spectrometer for peptide and protein separations and identifications.
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http://dx.doi.org/10.1016/j.aca.2015.06.035DOI Listing
August 2015

Simultaneously sizing and quantitating zeptomole-level DNA at high throughput in free solution.

Chemistry 2014 Oct 15;20(43):13945-50. Epub 2014 Sep 15.

Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019-5251 (USA).

Determining the sizes and measuring the quantities of DNA molecules are fundamental tasks in molecular biology. DNA sizes are usually evaluated by gel electrophoresis, but this method cannot simultaneously size and quantitate a DNA at low zeptomole (zmol) levels of concentration. We have recently developed a new technique, called bare-narrow-capillary/hydrodynamic-chromatography or BaNC-HDC, for resolving DNA based on their sizes without using any sieving matrices. In this report, we utilize BaNC-HDC for measuring the sizes and quantities of DNA fragments at zmol to several-molecule levels of concentration. DNA ranging from a few base pairs to dozens of kilo base pairs are accurately sized and quantitated at a throughput of 15 samples per hour, and each sample contains dozens of DNA strands of different lengths. BaNC-HDC can be a cost-effective means and an excellent tool for high-throughput DNA sizing and quantitation at extremely low quantity level.
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http://dx.doi.org/10.1002/chem.201403861DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4297202PMC
October 2014

Incorporating high-pressure electroosmotic pump and a nano-flow gradient generator into a miniaturized liquid chromatographic system for peptide analysis.

Anal Chim Acta 2014 Sep 27;844:90-8. Epub 2014 Jun 27.

Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA. Electronic address:

We integrate a high-pressure electroosmotic pump (EOP), a nanoflow gradient generator, and a capillary column into a miniaturized liquid chromatographic system that can be directly coupled with a mass spectrometer for proteomic analysis. We have recently developed a low-cost high-pressure EOP capable of generating pressure of tens of thousands psi, ideal for uses in miniaturized HPLC. The pump worked smoothly when it was used for isocratic elutions. When it was used for gradient elutions, generating reproducible gradient profiles was challenging; because the pump rate fluctuated when the pump was used to pump high-content organic solvents. This presents an issue for separating proteins/peptides since high-content organic solvents are often utilized. In this work, we solve this problem by incorporating our high-pressure EOP with a nano-flow gradient generator so that the EOP needs only to pump an aqueous solution. With this combination, we develop a capillary-based nano-HPLC system capable of performing nano-flow gradient elution; the pump rate is stable, and the gradient profiles are reproducible and can be conveniently tuned. To demonstrate its utility, we couple it with either a UV absorbance detector or a mass spectrometer for peptide separations.
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http://dx.doi.org/10.1016/j.aca.2014.06.042DOI Listing
September 2014

Role of Mediator in regulating Pol II elongation and nucleosome displacement in Saccharomyces cerevisiae.

Genetics 2012 May 29;191(1):95-106. Epub 2012 Feb 29.

Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130.

Mediator is a modular multisubunit complex that functions as a critical coregulator of RNA polymerase II (Pol II) transcription. While it is well accepted that Mediator plays important roles in the assembly and function of the preinitiation complex (PIC), less is known of its potential roles in regulating downstream steps of the transcription cycle. Here we use a combination of genetic and molecular approaches to investigate Mediator regulation of Pol II elongation in the model eukaryote, Saccharomyces cerevisiae. We find that ewe (expression without heat shock element) mutations in conserved Mediator subunits Med7, Med14, Med19, and Med21-all located within or adjacent to the middle module-severely diminish heat-shock-induced expression of the Hsf1-regulated HSP82 gene. Interestingly, these mutations do not impede Pol II recruitment to the gene's promoter but instead impair its transit through the coding region. This implies that a normal function of Mediator is to regulate a postinitiation step at HSP82. In addition, displacement of histones from promoter and coding regions, a hallmark of activated heat-shock genes, is significantly impaired in the med14 and med21 mutants. Suggestive of a more general role, ewe mutations confer hypersensitivity to the anti-elongation drug 6-azauracil (6-AU) and one of them-med21-impairs Pol II processivity on a GAL1-regulated reporter gene. Taken together, our results suggest that yeast Mediator, acting principally through its middle module, can regulate Pol II elongation at both heat-shock and non-heat-shock genes.
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http://dx.doi.org/10.1534/genetics.111.135806DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3338273PMC
May 2012

Overexpression of Pygopus2 protects HeLa cells from vinblastine-induced apoptosis.

Biol Chem 2009 Feb;390(2):157-65

The State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Hubei, PR China.

Pygopus, a very important component of the Wnt signaling transcriptional complex, has multiple functions in both Wnt-dependent and -independent pathways. Human Pygopus2 (Pygo2) is expressed in many cancers and plays an important role in tumor growth. In the present study, we generated human carcinoma (HeLa) cell lines stably expressing Pygo2, which counteracts vinblastine- induced apoptosis. The anti-apoptotic function was determined by DNA fragmentation, sub-G1 appearance, loss of mitochondrial membrane potential (Deltapsim) and the activation of caspase-9 and caspase-3. In addition, we found that Pygo2 effectively blocks vinblastineinduced c-Jun and AP-1 activation, maintains the anti-apoptotic protein Bcl-2 in an unphosphorylated state, and thus can render cells resistant to apoptosis. However, Pygo2 does not alter the vinblastine-induced cell cycle changes. Here, we describe an anti-apoptotic activity exerted by Pygo2 through blocking activation of the JNK/AP-1 signaling pathway induced by vinblastine.
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http://dx.doi.org/10.1515/BC.2009.014DOI Listing
February 2009