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Wehrli JM, Xia Y, Abivardi A, Kleim B, Bach DR. The impact of doxycycline on human contextual fear memory. Psychopharmacology (Berl) 2024; 241:1065-1077. [PMID: 38334789 PMCID: PMC11031495 DOI: 10.1007/s00213-024-06540-w] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 01/20/2024] [Indexed: 02/10/2024]
Abstract
RATIONALE Previous work identified an attenuating effect of the matrix metalloproteinase (MMP) inhibitor doxycycline on fear memory consolidation. This may present a new mechanistic approach for the prevention of trauma-related disorders. However, so far, this has only been unambiguously demonstrated in a cued delay fear conditioning paradigm, in which a simple geometric cue predicted a temporally overlapping aversive outcome. This form of learning is mainly amygdala dependent. Psychological trauma often involves the encoding of contextual cues, which putatively necessitates partly different neural circuits including the hippocampus. The role of MMP signalling in the underlying neural pathways in humans is unknown. METHODS Here, we investigated the effect of doxycycline on configural fear conditioning in a double-blind placebo-controlled randomised trial with 100 (50 females) healthy human participants. RESULTS Our results show that participants successfully learned and retained, after 1 week, the context-shock association in both groups. We find no group difference in fear memory retention in either of our pre-registered outcome measures, startle eye-blink responses and pupil dilation. Contrary to expectations, we identified elevated fear-potentiated startle in the doxycycline group early in the recall test, compared to the placebo group. CONCLUSION Our results suggest that doxycycline does not substantially attenuate contextual fear memory. This might limit its potential for clinical application.
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Affiliation(s)
- Jelena M Wehrli
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8008, Zurich, Switzerland
| | - Yanfang Xia
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8008, Zurich, Switzerland
| | - Aslan Abivardi
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8008, Zurich, Switzerland
- Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, FMRIB Building, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK
| | - Birgit Kleim
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8008, Zurich, Switzerland
| | - Dominik R Bach
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8008, Zurich, Switzerland.
- Wellcome Centre for Human Neuroimaging, University College London, Russell Square House, 10-12 Russell Square, London, WC1B 5EH, UK.
- Hertz Chair for Artificial Intelligence and Neuroscience, Transdisciplinary Research Area Life & Health , University of Bonn, Am Probsthof 49, 53121, Bonn, Germany.
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2
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Yap C, Wanga S, Wüst RCI, van Os BW, Pijls MME, Keijzer S, van Zanten E, Koolbergen DR, Driessen AHG, Balm R, Yeung KK, de Vries CJM, Houtkooper RH, Lindeman JHN, de Waard V. Doxycycline induces mitochondrial dysfunction in aortic smooth muscle cells. Vascul Pharmacol 2024; 154:107279. [PMID: 38272196 DOI: 10.1016/j.vph.2024.107279] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/29/2023] [Accepted: 01/22/2024] [Indexed: 01/27/2024]
Abstract
The antibiotic doxycycline is known to inhibit inflammation and was therefore considered as a therapeutic to prevent abdominal aortic aneurysm (AAA) growth. Yet mitochondrial dysfunction is a key-characteristic of clinical AAA disease. We hypothesize that doxycycline impairs mitochondrial function in the aorta and aortic smooth muscle cells (SMCs). Doxycycline induced mitonuclear imbalance, reduced proliferation and diminished expression of typical contractile smooth muscle cell (SMC) proteins. To understand the underlying mechanism, we studied krüppel-like factor 4 (KLF4). The expression of this transcription factor was enhanced in SMCs after doxycycline treatment. Knockdown of KLF4, however, did not affect the doxycycline-induced SMC phenotypic changes. Then we used the bioenergetics drug elamipretide (SS-31). Doxycycline-induced loss of SMC contractility markers was not rescued, but mitochondrial genes and mitochondrial connectivity improved upon elamipretide. Thus while doxycycline is anti-inflammatory, it also induces mitochondrial dysfunction in aortic SMCs and causes SMC phenotypic switching, potentially contributing to aortic aneurysm pathology. The drug elamipretide helps mitigate the harmful effects of doxycycline on mitochondrial function in aortic SMC, and may be of interest for treatment of aneurysm diseases with pre-existing mitochondrial dysfunction.
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Affiliation(s)
- Carmen Yap
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Shaynah Wanga
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam UMC location University of Amsterdam, Cardiology, Meibergdreef 9, Amsterdam, the Netherlands
| | - Rob C I Wüst
- Amsterdam UMC location Vrije Universiteit Amsterdam, Behavioural and Movement Sciences, Myology, Boelelaan 1117, Amsterdam, the Netherlands
| | - Bram W van Os
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Meibergdreef 9, Amsterdam, the Netherlands
| | - Maud M E Pijls
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Meibergdreef 9, Amsterdam, the Netherlands
| | - Sofie Keijzer
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Meibergdreef 9, Amsterdam, the Netherlands
| | - Eva van Zanten
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Meibergdreef 9, Amsterdam, the Netherlands
| | - David R Koolbergen
- Amsterdam UMC location University of Amsterdam, Cardiothoracic Surgery, Meibergdreef 9, Amsterdam, the Netherlands
| | - Antoine H G Driessen
- Amsterdam UMC location University of Amsterdam, Cardiothoracic Surgery, Meibergdreef 9, Amsterdam, the Netherlands
| | - Ron Balm
- Amsterdam UMC location University of Amsterdam, Vascular Surgery, Meibergdreef 9, Amsterdam, the Netherlands
| | - Kak Khee Yeung
- Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands; Amsterdam UMC location University of Amsterdam, Vascular Surgery, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam UMC location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1117, Amsterdam, Netherlands
| | - Carlie J M de Vries
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Riekelt H Houtkooper
- Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands; Amsterdam UMC location University of Amsterdam, Laboratory Genetic Metabolic Diseases, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Gastroenterology Endocrinology, and Metabolism, Amsterdam, the Netherlands
| | - Jan H N Lindeman
- Leiden University Medical Center, Vascular Surgery, Leiden, the Netherlands
| | - Vivian de Waard
- Amsterdam UMC location University of Amsterdam, Medical Biochemistry, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands.
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3
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Nishiji T, Hoshino A, Uchio Y, Matoba S. Generation of inducible mitophagy mice. Genes Cells 2024; 29:159-168. [PMID: 38131500 DOI: 10.1111/gtc.13091] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 11/22/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023]
Abstract
Mitophagy is programmed selective autophagy of mitochondria and is important for mitochondrial quality control and cellular homeostasis. Mitochondrial dysfunction and impaired mitophagy are closely associated with various diseases, including heart failure and diabetes. To better understand the pathophysiological role of mitophagy, we generated doxycycline-inducible mitophagy mice using a synthetic mitophagy adaptor protein consisting of an outer mitochondrial membrane targeting sequence and an engineered LIR. To evaluate the activation of mitophagy upon doxycycline treatment, we also generated mitophagy reporter mito-QC mice in which mitochondria tandemly express mCherry and GFP, and only GFP signals are lost in acidic lysosomes subjected to mitophagy. With the ROSA26 promoter-driven rtTA, mitophagy was observed at least in heart, liver, and skeletal muscle. We investigated the relationship between mitophagy activation and pressure overload heart failure or high fat diet-induced obesity. Unexpectedly, we were unable to confirm the protective effect of mitophagy in these two pathological models. Further titration of the level of mitophagy induction is required to demonstrate the potency of the protective effects of mitophagy in disease models.
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Affiliation(s)
- Toshiyuki Nishiji
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Atsushi Hoshino
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuki Uchio
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoaki Matoba
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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4
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Zhu Y, Jen A, Overmyer KA, Gao AW, Shishkova E, Auwerx J, Coon JJ. Mass Spectrometry-Based Multi-omics Integration with a Single Set of C. elegans Samples. Anal Chem 2023; 95:10930-10938. [PMID: 37432911 PMCID: PMC10863427 DOI: 10.1021/acs.analchem.3c00734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
Mass spectrometry-based large-scale multi-omics research has proven to be powerful in answering biological questions; nonetheless, it faces many challenges from sample preparation to downstream data integration. To efficiently extract biomolecules of different physicochemical properties, preparation of various sample type needs specific tailoring, especially of difficult ones, such as Caenorhabditis elegans. In this study, we sought to develop a multi-omics sample preparation method starting with a single set ofC. elegans samples to save time, minimize variability, expand biomolecule coverage, and promote multi-omics integration. We investigated tissue disruption methods to effectively release biomolecules and optimized extraction strategies to achieve broader and more reproducible biomolecule coverage in proteomics, lipidomics, and metabolomics workflows. In our assessment, we also considered speediness and usability of the approaches. The developed method was validated through a study of 16C. elegans samples designed to shine light on mitochondrial unfolded protein response (UPRmt), induced by three unique stressors─knocking down electron transfer chain element cco-1, mitochondrial ribosome protein S5 mrps-5, and antibiotic treatment Doxycycline. Our findings suggested that the method achieved great coverage of proteome, lipidome, and metabolome with high reproducibility and validated that all stressors triggered UPRmt in C. elegans, although generating unique molecular signatures. Innate immune response was activated, and triglycerides were decreased under all three stressor conditions. Additionally, Doxycycline treatment elicited more distinct proteomic, lipidomic, and metabolomic response than the other two treatments. This method has been successfully used to process Saccharomyces cerevisiae (data not shown) and can likely be applied to other organisms for multi-omics research.
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Affiliation(s)
- Yunyun Zhu
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
| | - Annie Jen
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
| | - Katherine A Overmyer
- National Center for Quantitative Biology of Complex Systems, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53515, USA
- Department of Chemistry, University of Wisconsin, Madison, WI 53506, USA
| | - Arwen W Gao
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Evgenia Shishkova
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
- National Center for Quantitative Biology of Complex Systems, Madison, WI 53706, USA
| | - Johan Auwerx
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Joshua J Coon
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
- National Center for Quantitative Biology of Complex Systems, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53515, USA
- Department of Chemistry, University of Wisconsin, Madison, WI 53506, USA
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5
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Linesch PW, Akhtar AA, Breunig JJ. Tetracycline-Inducible and Reversible Stable Gene Expression in Human iPSC-Derived Neural Progenitors and in the Postnatal Mouse Brain. Curr Protoc 2023; 3:e792. [PMID: 37283517 PMCID: PMC10264152 DOI: 10.1002/cpz1.792] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Our group has developed several approaches for stable, non-viral integration of inducible transgenic elements into the genome of mammalian cells. Specifically, a piggyBac tetracycline-inducible genetic element of interest (pB-tet-GOI) plasmid system allows for stable piggyBac transposition-mediated integration into cells, identification of cells that have been transfected using a fluorescent nuclear reporter, and robust transgene activation or suppression upon the addition of doxycycline (dox) to the cell culture or the diet of the animal. Furthermore, the addition of luciferase downstream of the target gene allows for quantitative assessment of gene activity in a non-invasive manner. More recently, we have developed a transgenic system as an alternative to piggyBac called mosaic analysis by dual recombinase-mediated cassette exchange (MADR), as well as additional in vitro transfection techniques and in vivo dox chow applications. The protocols herein provide instructions for the use of this system in cell lines and in the neonatal mouse brain. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Cloning of respective genetic element of interest (GOI) into response plasmid Basic Protocol 2: In vitro nucleofection of iPSC-derived human/mouse neural progenitor cells and subsequent derivation of stable inducible cell lines Alternate Protocol: In vitro electroporation of iPSC-derived human/mouse neural progenitor cells Support Protocol: Recovery stage after in vitro transfection Basic Protocol 3: Adding doxycycline to cells to induce/reverse GOI Basic Protocol 4: Assessing gene expression in vitro by non-invasive bioluminescence imaging of luciferase activity.
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Affiliation(s)
- Paul W. Linesch
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Aslam Abbasi Akhtar
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Joshua J. Breunig
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
- Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Division of Applied Cell Biology and Physiology, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Medicine, UCLA, Los Angeles, California
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6
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Kaur G, Singh N, Rajor A, Arya RK. Removal of doxycycline hydrochloride from aqueous solution by rice husk ash using response surface methodology and disposability study. Environ Sci Pollut Res Int 2023; 30:8485-8499. [PMID: 35157206 PMCID: PMC8853133 DOI: 10.1007/s11356-022-18961-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/26/2022] [Indexed: 05/06/2023]
Abstract
The huge demand and consumption of DOX, its incomplete metabolism, and complex behavior in atmosphere are causing a great ecological issue, which needs to be solved. In the present study, the suitability of rice husk ash (RHA) for the greater sorption efficiency of DOX antibiotic was investigated. Furthermore, disposability study of exhausted RHA was performed using solidification technique and leachate had undergone toxicity test to evaluate the DOX encapsulation ability. The central composite design under RSM was employed for the design of experiment and optimization of adsorption parameters. RHA was characterized using various techniques such as XRD, SEM (EDX), FTIR, BET, and zeta potential analysis. The influence of various adsorption parameters, like initial DOX concentration (C0), RHA dosage (m), incubation-time period (t), and pH were examined on the performance in terms of DOX elimination % (X1) and adsorptive capacity (mg/g) (X2). At optimized conditions, the obtained X1 and X2 were 98.85% and 17.74 mg/g, respectively. Moreover, the kinetics data suited well to the pseudo-second-order model. Freundlich, Langmuir, and Redlich-Peterson (R-P) isotherm models were applied, out of which Langmuir model best performed under optimized conditions; m = 5 g/L, t = 85.85 min, DOX concentration = 89.73 mg/L, and pH = 6. The bacterial toxicity test of leachate confirmed complete encapsulation of DOX by solidification technique.
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Affiliation(s)
- Gurleenjot Kaur
- School of Energy and Environment, Thapar Institute of Engineering and Technology, Patiala, 147004 India
| | - Neetu Singh
- Department of Chemical Engineering, Thapar Institute of Engineering and Technology, Patiala, 147004 India
| | - Anita Rajor
- School of Energy and Environment, Thapar Institute of Engineering and Technology, Patiala, 147004 India
| | - Raj Kumar Arya
- Department of Chemical Engineering, Dr. B.R. Ambedkar National Institute of Technology, Jalandhar, India
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Goodlett BL, Balasubbramanian D, Navaneethabalakrishnan S, Love SE, Luera EM, Konatham S, Chiasson VL, Wedgeworth S, Rutkowski JM, Mitchell BM. Genetically inducing renal lymphangiogenesis attenuates hypertension in mice. Clin Sci (Lond) 2022; 136:1759-1772. [PMID: 36345993 PMCID: PMC10586591 DOI: 10.1042/cs20220547] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [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: 08/16/2022] [Revised: 11/03/2022] [Accepted: 11/08/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND Hypertension (HTN) is associated with renal proinflammatory immune cell infiltration and increased sodium retention. We reported previously that renal lymphatic vessels, which are responsible for trafficking immune cells from the interstitial space to draining lymph nodes, increase in density under hypertensive conditions. We also demonstrated that augmenting renal lymphatic density can prevent HTN in mice. Whether renal lymphangiogenesis can treat HTN in mice is unknown. We hypothesized that genetically inducing renal lymphangiogenesis after the establishment of HTN would attenuate HTN in male and female mice from three different HTN models. METHODS Mice with inducible kidney-specific overexpression of VEGF-D (KidVD) experience renal lymphangiogenesis upon doxycycline administration. HTN was induced in KidVD+ and KidVD- mice by subcutaneous release of angiotensin II, administration of the nitric oxide synthase inhibitor L-NAME, or consumption of a 4% salt diet following a L-NAME priming and washout period. After a week of HTN stimuli treatment, doxycycline was introduced. Systolic blood pressure (SBP) readings were taken weekly. Kidney function was determined from urine and serum measures. Kidneys were processed for RT-qPCR, flow cytometry, and imaging. RESULTS Mice that underwent renal-specific lymphangiogenesis had significantly decreased SBP and renal proinflammatory immune cells. Additionally, renal lymphangiogenesis was associated with a decrease in sodium transporter expression and increased fractional excretion of sodium, indicating improved sodium handling efficiency. CONCLUSIONS These findings demonstrate that augmenting renal lymphangiogenesis can treat HTN in male and female mice by improving renal immune cell trafficking and sodium handling.
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Affiliation(s)
- Bethany L Goodlett
- Department of Medical Physiology, Texas A&M University College of Medicine, Bryan, TX, U.S.A
| | | | | | - Sydney E Love
- Department of Medical Physiology, Texas A&M University College of Medicine, Bryan, TX, U.S.A
| | - Emily M Luera
- Department of Medical Physiology, Texas A&M University College of Medicine, Bryan, TX, U.S.A
| | - Sunitha Konatham
- Department of Medical Physiology, Texas A&M University College of Medicine, Bryan, TX, U.S.A
| | - Valorie L Chiasson
- Department of Medical Physiology, Texas A&M University College of Medicine, Bryan, TX, U.S.A
| | - Sophie Wedgeworth
- Department of Medical Physiology, Texas A&M University College of Medicine, Bryan, TX, U.S.A
| | - Joseph M Rutkowski
- Department of Medical Physiology, Texas A&M University College of Medicine, Bryan, TX, U.S.A
| | - Brett M Mitchell
- Department of Medical Physiology, Texas A&M University College of Medicine, Bryan, TX, U.S.A
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Chen FY, Geng CA, Chou CK, Zheng JB, Yang Y, Wang YF, Li TZ, Li P, Chen JJ, Chen X. Distepharinamide, a novel dimeric proaporphine alkaloid from Diploclisia glaucescens, inhibits the differentiation and proliferative expansion of CD4 +Foxp3 + regulatory T cells. Phytomedicine 2022; 107:154482. [PMID: 36202057 DOI: 10.1016/j.phymed.2022.154482] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 09/17/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND CD4+Foxp3+ regulatory T cells (Tregs) represent the primary cellular mechanism of tumor immune evasion. Elimination of Treg activity by the pharmacological agent may enhance anti-tumor immune responses. However, Treg-eliminating agents, especially those with small molecules, are rarely reported. PURPOSE To identify small molecule inhibitors of Treg cells from natural products. METHODS Compounds from Diploclisia glaucescens were isolated by column chromatography, and structures were identified by spectroscopic evidence and quantum calculations. The tet-On system for Foxp3-GFP expression in Jurkat T cells was generated to screen Treg inhibitors based on Foxp3 expression. The effect of the compound on TNF-induced proliferative expansion of naturally occurring Tregs (nTregs) and TGF-β-induced generation of Tregs (iTregs) from naive CD4+ Tcells was further examined. RESULTS A novel dimeric proaporphine alkaloid, designated as distepharinamide (DSA) with a symmetric structure isolated from the stems of D. glaucescens, restrained the doxycycline (Doxy)-induced Foxp3-tGFP expression, decreased the half-life of Foxp3 mRNA as well as reduced the mRNA levels of chemokine receptors (CCR4, CCR8 and CCR10) in Jurkat T cells with inducible Foxp3-tGFP expression. In lymphocytes or purified Tregs from wild-type C57BL/6 mice or from C57BL/6-Tg(Foxp3-DTR/EGFP)23.2Spar/Mmjax mice, DSA markedly inhibited TNF-induced proliferative expansion of Tregs present in the unfractionated CD4+ T cells, accompanied by the down-regulation of TNFR2, CD25 and CTLA4 expression on Tregs. Furthermore, DSA potently inhibited TGF-β-induced differentiation of Foxp3-expressing iTregs. Importantly, the expression of Foxp3 mRNA by both nTregs and iTregs was decreased by DSA treatment. Nevertheless, DSA at the same concentrations did not inhibit the proliferation of conventional CD4+ and CD8+ T cells stimulated by anti-CD3/CD28 antibodies. CONCLUSION DSA, a novel dimeric proaporphine alkaloid, potently inhibited the expansion of nTregs and generation of iTregs. Therefore, DSA or its analogs may merit further investigation as novel immunotherapeutic agents.
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Affiliation(s)
- Feng-Yang Chen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macau 999078, China; School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou 310053, China
| | - Chang-An Geng
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Chon-Kit Chou
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macau 999078, China
| | - Jing-Bin Zheng
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macau 999078, China
| | - Yang Yang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macau 999078, China
| | - Yi-Fei Wang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macau 999078, China
| | - Tian-Ze Li
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Ping Li
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macau 999078, China
| | - Ji-Jun Chen
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
| | - Xin Chen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Science, University of Macau, Macau 999078, China.
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9
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Huu Hoang T, Sato-Matsubara M, Yuasa H, Matsubara T, Thuy LTT, Ikenaga H, Phuong DM, Hanh NV, Hieu VN, Hoang DV, Hai H, Okina Y, Enomoto M, Tamori A, Daikoku A, Urushima H, Ikeda K, Dat NQ, Yasui Y, Shinkawa H, Kubo S, Yamagishi R, Ohtani N, Yoshizato K, Gracia-Sancho J, Kawada N. Cancer cells produce liver metastasis via gap formation in sinusoidal endothelial cells through proinflammatory paracrine mechanisms. Sci Adv 2022; 8:eabo5525. [PMID: 36170363 PMCID: PMC9519040 DOI: 10.1126/sciadv.abo5525] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 08/04/2022] [Indexed: 06/10/2023]
Abstract
Intracellular gap (iGap) formation in liver sinusoidal endothelial cells (LSECs) is caused by the destruction of fenestrae and appears under pathological conditions; nevertheless, their role in metastasis of cancer cells to the liver remained unexplored. We elucidated that hepatotoxin-damaged and fibrotic livers gave rise to LSECs-iGap formation, which was positively correlated with increased numbers of metastatic liver foci after intrasplenic injection of Hepa1-6 cells. Hepa1-6 cells induced interleukin-23-dependent tumor necrosis factor-α (TNF-α) secretion by LSECs and triggered LSECs-iGap formation, toward which their processes protruded to transmigrate into the liver parenchyma. TNF-α triggered depolymerization of F-actin and induced matrix metalloproteinase 9 (MMP9), intracellular adhesion molecule 1, and CXCL expression in LSECs. Blocking MMP9 activity by doxycycline or an MMP2/9 inhibitor eliminated LSECs-iGap formation and attenuated liver metastasis of Hepa1-6 cells. Overall, this study revealed that cancer cells induced LSEC-iGap formation via proinflammatory paracrine mechanisms and proposed MMP9 as a favorable target for blocking cancer cell metastasis to the liver.
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Affiliation(s)
- Truong Huu Hoang
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
- Department of Pain Medicine and Palliative Care, Cancer Institute, 108 Military Central Hospital, Hanoi, Vietnam
| | - Misako Sato-Matsubara
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
- Endowed Laboratory of Synthetic Biology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Hideto Yuasa
- Department of Anatomy and Regenerative Biology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Tsutomu Matsubara
- Department of Anatomy and Regenerative Biology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Le Thi Thanh Thuy
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Hiroko Ikenaga
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Dong Minh Phuong
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Ngo Vinh Hanh
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Vu Ngoc Hieu
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Dinh Viet Hoang
- Department of Anesthesiology, Cho Ray Hospital, Ho Chi Minh City, Vietnam
| | - Hoang Hai
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Yoshinori Okina
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Masaru Enomoto
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Akihiro Tamori
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Atsuko Daikoku
- Department of Anatomy and Regenerative Biology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Hayato Urushima
- Department of Anatomy and Regenerative Biology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Kazuo Ikeda
- Department of Anatomy and Regenerative Biology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Ninh Quoc Dat
- Department of Pediatrics, Hanoi Medical University, Hanoi, Vietnam
| | - Yutaka Yasui
- Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan
| | - Hiroji Shinkawa
- Department of Hepato-Biliary-Pancreatic Surgery, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Shoji Kubo
- Department of Hepato-Biliary-Pancreatic Surgery, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Ryota Yamagishi
- Department of Pathophysiology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Naoko Ohtani
- Department of Pathophysiology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Katsutoshi Yoshizato
- Endowed Laboratory of Synthetic Biology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
- BioIntegrence Co. Ltd., Osaka, Japan
| | - Jordi Gracia-Sancho
- Liver Vascular Biology Research Group, IDIBAPS Biomedical Research Institute, CIBEREHD, Barcelona, Spain
| | - Norifumi Kawada
- Department of Hepatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
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10
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Dudakovic A, Jerez S, Deosthale PJ, Denbeigh JM, Paradise CR, Gluscevic M, Zan P, Begun DL, Camilleri ET, Pichurin O, Khani F, Thaler R, Lian JB, Stein GS, Westendorf JJ, Plotkin LI, van Wijnen AJ. MicroRNA-101a enhances trabecular bone accrual in male mice. Sci Rep 2022; 12:13361. [PMID: 35922466 PMCID: PMC9349183 DOI: 10.1038/s41598-022-17579-0] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 07/27/2022] [Indexed: 11/09/2022] Open
Abstract
High-throughput microRNA sequencing was performed during differentiation of MC3T3-E1 osteoblasts to develop working hypotheses for specific microRNAs that control osteogenesis. The expression data show that miR-101a, which targets the mRNAs for the epigenetic enzyme Ezh2 and many other proteins, is highly upregulated during osteoblast differentiation and robustly expressed in mouse calvaria. Transient elevation of miR-101a suppresses Ezh2 levels, reduces tri-methylation of lysine 27 in histone 3 (H3K27me3; a heterochromatic mark catalyzed by Ezh2), and accelerates mineralization of MC3T3-E1 osteoblasts. We also examined skeletal phenotypes of an inducible miR-101a transgene under direct control of doxycycline administration. Experimental controls and mir-101a over-expressing mice were exposed to doxycycline in utero and postnatally (up to 8 weeks of age) to maximize penetrance of skeletal phenotypes. Male mice that over-express miR-101a have increased total body weight and longer femora. MicroCT analysis indicate that these mice have increased trabecular bone volume fraction, trabecular number and trabecular thickness with reduced trabecular spacing as compared to controls. Histomorphometric analysis demonstrates a significant reduction in osteoid volume to bone volume and osteoid surface to bone surface. Remarkably, while female mice also exhibit a significant increase in bone length, no significant changes were noted by microCT (trabecular bone parameters) and histomorphometry (osteoid parameters). Hence, miR-101a upregulation during osteoblast maturation and the concomitant reduction in Ezh2 mediated H3K27me3 levels may contribute to the enhanced trabecular bone parameters in male mice. However, the sex-specific effect of miR-101a indicates that more intricate epigenetic mechanisms mediate physiological control of bone formation and homeostasis.
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Affiliation(s)
- Amel Dudakovic
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA.
- Department of Biochemistry & Molecular Biology, Mayo Clinic, Rochester, MN, USA.
| | - Sofia Jerez
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Padmini J Deosthale
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Janet M Denbeigh
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Christopher R Paradise
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, USA
- Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Martina Gluscevic
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
- Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Pengfei Zan
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
- Department of Orthopedic Surgery, School of Medicine, Second Affiliated Hospital of Zhejiang University, Hangzhou, China
- Department of Orthopedic Surgery, School of Medicine, Shanghai Tenth People's Hospital Affiliated to Tongji University, Shanghai, China
| | - Dana L Begun
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | | | - Oksana Pichurin
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Farzaneh Khani
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Roman Thaler
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Jane B Lian
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | - Gary S Stein
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | - Jennifer J Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
- Department of Biochemistry & Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Lilian I Plotkin
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA.
- Richard L Roudebush VA Medical Center, Indianapolis, IN, USA.
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11
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Alvarez-Manzo HS, Davidson RK, Van Cauwelaert de Wyels J, Cotten KL, Nguyen BH, Xiao M, Zhu Z, Anthony J, van Opijnen T, Davis KM. Yersinia pseudotuberculosis doxycycline tolerance strategies include modulating expression of genes involved in cell permeability and tRNA modifications. PLoS Pathog 2022; 18:e1010556. [PMID: 35576231 PMCID: PMC9135342 DOI: 10.1371/journal.ppat.1010556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 05/26/2022] [Accepted: 04/27/2022] [Indexed: 11/19/2022] Open
Abstract
Antibiotic tolerance is typically associated with a phenotypic change within a bacterial population, resulting in a transient decrease in antibiotic susceptibility that can contribute to treatment failure and recurrent infections. Although tolerant cells may emerge prior to treatment, the stress of prolonged antibiotic exposure can also promote tolerance. Here, we sought to determine how Yersinia pseudotuberculosis responds to doxycycline exposure, to then verify if these gene expression changes could promote doxycycline tolerance in culture and in our mouse model of infection. Only four genes were differentially regulated in response to a physiologically-relevant dose of doxycycline: osmB and ompF were upregulated, tusB and cnfy were downregulated; differential expression also occurred during doxycycline treatment in the mouse. ompF, tusB and cnfy were also differentially regulated in response to chloramphenicol, indicating these could be general responses to ribosomal inhibition. cnfy has previously been associated with persistence and was not a major focus here. We found deletion of the OmpF porin resulted in increased antibiotic accumulation, suggesting expression may promote diffusion of doxycycline out of the cell, while OsmB lipoprotein had a minor impact on antibiotic permeability. Overexpression of tusB significantly impaired bacterial survival in culture and in the mouse, suggesting that tRNA modification by tusB, and the resulting impacts on translational machinery, promotes survival during treatment with an antibiotic classically viewed as bacteriostatic. We believe this may be the first observation of bactericidal activity of doxycycline under physiological conditions, which was revealed by reversing tusB downregulation.
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Affiliation(s)
- Hector S. Alvarez-Manzo
- W. Harry Feinstone Department of Molecular Microbiology and Immunology Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Robert K. Davidson
- W. Harry Feinstone Department of Molecular Microbiology and Immunology Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Jasper Van Cauwelaert de Wyels
- W. Harry Feinstone Department of Molecular Microbiology and Immunology Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Katherine L. Cotten
- W. Harry Feinstone Department of Molecular Microbiology and Immunology Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Benjamin H. Nguyen
- W. Harry Feinstone Department of Molecular Microbiology and Immunology Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Melody Xiao
- W. Harry Feinstone Department of Molecular Microbiology and Immunology Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Zeyu Zhu
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Jon Anthony
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Tim van Opijnen
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Kimberly Michele Davis
- W. Harry Feinstone Department of Molecular Microbiology and Immunology Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
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12
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Khoshdel AR, Emami Aleagha O, Shahriary A, Aghamollaei H, Najjar Asiabani F. Topical Effects of N-Acetyl Cysteine and Doxycycline on Inflammatory and Angiogenic Factors in the Rat Model of Alkali-Burned Cornea. J Interferon Cytokine Res 2022; 42:82-89. [PMID: 35029525 DOI: 10.1089/jir.2021.0150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The aim of this study was to analyze the single and combined effects of N-acetyl cysteine (NAC) and doxycycline (Dox) on the inflammatory and angiogenic factors in the rat model of alkali-burned cornea. Rats were treated with a single and combined 0.5% NAC and 12.5 μg/mL Dox eye drops and evaluated on days 3, 7, and 28. In the corneas of various groups, the activity of Catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) enzymes was assessed. The expression of inflammatory factors (TNF-α, Rel-a, and CXCL-1) and angiogenic factors (VEGF-a, MMP2, and MMP9) was measured using real-time polymerase chain reaction. The antioxidant enzyme activities decreased substantially 3 days after injury with sodium hydroxide (NaOH). NAC and combined NAC+ Dox topical treatments increased the SOD enzyme activity on day 28 (P < 0.05). The expression of TNF-α and Rel-a genes following single and combined treatment of NAC and Dox decreased significantly on days 7 and 28 (P < 0.05). The mRNA level of angiogenic factors and corneal neovascularization (CNV) level declined in NaOH-injured rats treated with Dox (P < 0.05). The topical treatment of Dox could attenuate inflammation and CNV complications. However, NAC treatment may not reduce the expression of angiogenic genes.
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Affiliation(s)
- Ali Reza Khoshdel
- Modern Epidemiology Research Center, AJA University of Medical Sciences, Tehran, Iran
| | - Omid Emami Aleagha
- Modern Epidemiology Research Center, AJA University of Medical Sciences, Tehran, Iran
| | - Alireza Shahriary
- Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Hossein Aghamollaei
- Applied Virology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
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13
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Li R, Xia X, Wang X, Sun X, Dai Z, Huo D, Zheng H, Xiong H, He A, Wu X. Generation and validation of versatile inducible CRISPRi embryonic stem cell and mouse model. PLoS Biol 2020; 18:e3000749. [PMID: 33253175 PMCID: PMC7728392 DOI: 10.1371/journal.pbio.3000749] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 12/10/2020] [Accepted: 11/02/2020] [Indexed: 01/09/2023] Open
Abstract
Clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated (Cas) 9 has been widely used far beyond genome editing. Fusions of deactivated Cas9 (dCas9) to transcription effectors enable interrogation of the epigenome and controlling of gene expression. However, the large transgene size of dCas9-fusion hinders its applications especially in somatic tissues. Here, we develop a robust CRISPR interference (CRISPRi) system by transgenic expression of doxycycline (Dox) inducible dCas9-KRAB in mouse embryonic stem cells (iKRAB ESC). After introduction of specific single-guide RNAs (sgRNAs), the induced dCas9-KRAB efficiently maintains gene inactivation, although it modestly down-regulates the expression of active genes. The proper timing of Dox addition during cell differentiation or reprogramming allows us to study or screen spatiotemporally activated promoters or enhancers and thereby the gene functions. Furthermore, taking the ESC for blastocyst injection, we generate an iKRAB knock-in (KI) mouse model that enables the shutdown of gene expression and loss-of-function (LOF) studies ex vivo and in vivo by a simple transduction of gRNAs. Thus, our inducible CRISPRi ESC line and KI mouse provide versatile and convenient platforms for functional interrogation and high-throughput screens of specific genes and potential regulatory elements in the setting of development or diseases.
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Affiliation(s)
- Rui Li
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory of Cellular Homeostasis and Human Diseases, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Xianyou Xia
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory of Cellular Homeostasis and Human Diseases, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Xing Wang
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory of Cellular Homeostasis and Human Diseases, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Xiaoyu Sun
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory of Cellular Homeostasis and Human Diseases, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Zhongye Dai
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory of Cellular Homeostasis and Human Diseases, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Dawei Huo
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory of Cellular Homeostasis and Human Diseases, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Huimin Zheng
- Department of Prosthodontics, School and Hospital of Stomatology, Tianjin Medical University, Tianjin, China
| | - Haiqing Xiong
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Aibin He
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Xudong Wu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory of Cellular Homeostasis and Human Diseases, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Key Laboratory of Epigenetics for Organ Development of Premature Infants, Tianjin, China
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14
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Wen X, Huang J, Cao J, Xu J, Mi J, Wang Y, Ma B, Zou Y, Liao X, Liang JB, Wu Y. Heterologous expression of the tetracycline resistance gene tetX to enhance degradability and safety in doxycycline degradation. Ecotoxicol Environ Saf 2020; 191:110214. [PMID: 31968275 DOI: 10.1016/j.ecoenv.2020.110214] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/06/2020] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
Microbial remediation has the potential to inexpensively yet effectively decontaminate and restore contaminated environments, but the virulence of pathogens and risk of resistance gene transmission by microorganisms during antibiotic removal often limit its implementation. Here, a cloned tetX gene with clear evolutionary history was expressed to explore doxycycline (DOX) degradation and resistance variation during the degradation process. Phylogenetic analysis of tetX genes showed high similarity with those of pathogenic bacteria, such as Riemerella sp. and Acinetobacter sp. Successful tetX expression was performed in Escherichia coli and confirmed by SDS-PAGE and Western blot. Our results showed that 95.0 ± 1.0% of the DOX (50 mg/L) was degraded by the recombinant strain (ETD-1 with tetX) within 48 h, which was significantly higher than that for the control (38.9 ± 8.7%) and the empty plasmid bacteria (8.8 ± 5.1%) (P < 0.05). The tetX gene products in ETD-1 cell extracts also exhibited an efficient DOX degradation ability, with a degradation rate of 80.5 ± 1.2% at 168 h. Furthermore, there was no significant proliferation of the tetX resistance gene during DOX degradation (P > 0.05). The efficient and safe DOX-degrading capacity of the recombinant strain ETD-1 makes it valuable and promising for antibiotic removal in the environment.
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Affiliation(s)
- Xin Wen
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; Ministry of Agriculture Key Laboratory of Tropical Agricultural Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Jielan Huang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; Ministry of Agriculture Key Laboratory of Tropical Agricultural Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Junchao Cao
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; Ministry of Agriculture Key Laboratory of Tropical Agricultural Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Jiangran Xu
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; Ministry of Agriculture Key Laboratory of Tropical Agricultural Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Jiandui Mi
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; Ministry of Agriculture Key Laboratory of Tropical Agricultural Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Enterprise Lab of Healthy Animal Husbandry and Environment Control, Yunfu, Xinxing, 527400, China
| | - Yan Wang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; Ministry of Agriculture Key Laboratory of Tropical Agricultural Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Enterprise Lab of Healthy Animal Husbandry and Environment Control, Yunfu, Xinxing, 527400, China
| | - Baohua Ma
- Nanhai Office of Foshan Customs House, Foshan, 528200, China
| | - Yongde Zou
- Nanhai Office of Foshan Customs House, Foshan, 528200, China
| | - Xindi Liao
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; Ministry of Agriculture Key Laboratory of Tropical Agricultural Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Enterprise Lab of Healthy Animal Husbandry and Environment Control, Yunfu, Xinxing, 527400, China
| | - Juan Boo Liang
- Laboratory of Animal Production, Institute of Tropical Agriculture, Universiti Putra Malaysia, Serdang, 43400, Malaysia
| | - Yinbao Wu
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China; Ministry of Agriculture Key Laboratory of Tropical Agricultural Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Enterprise Lab of Healthy Animal Husbandry and Environment Control, Yunfu, Xinxing, 527400, China.
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15
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Mitani A, Kobayashi T, Hayashi Y, Matsushita N, Matsushita S, Nakao S, Takahira N, Shiraishi A, Ohashi Y. Characterization of doxycycline-dependent inducible Simian Virus 40 large T antigen immortalized human conjunctival epithelial cell line. PLoS One 2019; 14:e0222454. [PMID: 31509592 PMCID: PMC6738650 DOI: 10.1371/journal.pone.0222454] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/29/2019] [Indexed: 11/19/2022] Open
Abstract
PURPOSE To present the properties of a newly developed immortalized human conjunctival epithelial cell (iHCjEC) line. METHODS iHCjECs were developed to induce Simian Virus 40 large T-antigen (SV40LT) by incorporating lentivirus in a tetracycline (Tet)-regulated gene-expression system into primary cultures of human conjunctival epithelial cells. The population doubling time and morphology of the iHCjECs were analyzed. The expressions of CK13, CK19, CK12, and MUC1, MUC4, MUC16, and MUC5AC were determined by real time PCR and immunohistochemically under different culture conditions. The organotypic culture model in which iHCjECs were cultured on rabbit conjunctival fibroblast-embedded collagen gel was used to characterize the iHCjECs. RESULTS The iHCjECs cultured with doxycycline (Dox) continued to proliferate for at least 20 passages and had a cobblestone-like appearance. The expressions of CK13 and CK19 but not CK12 were detected in the iHCjECs, and the expression of CK13 increased in culture media lacking Dox (Dox-). The expressions of MUC1, MUC4, MUC16, and MUC5AC were detected in iHCjECs, and a relatively strong immunostaining of MUC5AC was detected with Dox(-) added 5% FBS. Stratified iHCjECs were observed in organotypic culture at 5 days. CONCLUSION The iHCjECs had high proliferation rates and abilities to control the differentiation potency to control the expression of SV40 LT-antigen with Tet-regulated gene-expression system. They are able to express the mucin gene repertoire of their native epithelia. The iHCjECs can be a useful experimental cell line to study conjunctival epithelial cell characteristics and for pathophysiological and toxicological studies.
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Affiliation(s)
- Arisa Mitani
- Department of Ophthalmology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
- * E-mail:
| | - Takeshi Kobayashi
- Department of Ophthalmology and Regenerative Medicine, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Yasuhito Hayashi
- Department of Ophthalmology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Natsuki Matsushita
- Division of Laboratory Animal Research, Aichi Medical University, Nagakute, Aichi, Japan
- Translational Research Center, Ehime University Hospital, Toon, Ehime, Japan
| | - Sachi Matsushita
- Translational Research Center, Ehime University Hospital, Toon, Ehime, Japan
- Department of Biochemistry, Aichi Gakuin University School of Dentistry, Nagoya, Japan
| | - Saori Nakao
- Department of Ophthalmology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Naoko Takahira
- Department of Ophthalmology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Atsushi Shiraishi
- Department of Ophthalmology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
- Translational Research Center, Ehime University Hospital, Toon, Ehime, Japan
| | - Yuichi Ohashi
- Department of Ophthalmology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
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16
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Abstract
Biomolecule-nanoparticle hybrids have proven to be one of most promising frontiers in biomedical research. In recent years, there has been an increased focus on the development of hybrid lipid-nanoparticle complexes (HLNCs) which inherit unique properties of both the inorganic nanoparticles and the lipid assemblies (i.e. liposomes, lipoproteins, solid lipid nanoparticles, and nanoemulsions) that comprise them. In combination of their component parts, HLNCs also gain new functionalities which are utilized for numerous biomedical applications (i.e. stimuli-triggered drug release, photothermal therapy, and bioimaging). The localization of nanoparticles within the lipid assemblies largely dictates the attributes and functionalities of the hybrid complexes and are classified as such: (i) liposomes with surface-bound nanoparticles, (ii) liposomes with bilayer-embedded nanoparticles, (iii) liposomes with core-encapsulated nanoparticles, (iv) lipid assemblies with hydrophobic core-encapsulated nanoparticles, and (v) lipid bilayer-coated nanoparticles. Herein, we review the properties of each hybrid and the rational design of HLNCs for biomedical applications as reported by recent investigations. Future directions in advancing and expanding the scope of HLNCs are also proposed.
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Affiliation(s)
- Kevin M Vargas
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, California 90840-9507, USA
| | - Young-Seok Shon
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, California 90840-9507, USA
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17
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Shi H, Bai C, Luo D, Wang W, Zhou C, Meharg AA, Yao L. Degradation of tetracyclines in manure-amended soil and their uptake by litchi (Litchi chinensis Sonn.). Environ Sci Pollut Res Int 2019; 26:6209-6215. [PMID: 30617894 DOI: 10.1007/s11356-018-04077-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
The environmental and human health risk posed by veterinary antibiotics is of global concern. Antibiotic uptake by herbal plants has been studied, but little is known about perennial woody fruit crops. Litchi (Litchi chinensis Sonn.), a longevial fruit tree, is routinely fertilized with animal manure and, therefore, may be at risk of antibiotic uptake into its fruits. This study investigated the degradation of chlortetracycline and doxycycline present in manure used to amend orchard soil, and their subsequent assimilation by litchi plant, as affected by manure application rate. The results show that half-lives of chlortetracycline and doxycycline in soil were decreased by increased manure rate, with an average of 27 and 59 days, respectively. Chlortetracycline was readily transported to litchi shoots and increased with the growth of litchi plants. Doxycycline predominantly remained in the roots, and underwent growth dilution in the plants. The two tetracyclines could not be detected in fruits from litchi trees when applied with manures, at various rates, over 2 years. For litchi, chlortetracycline may pose human health risk through manure application, but doxycycline is unlikely to do so. Long-term field experiments are required to monitor antibiotic accumulation in fruits of perennial fruit trees fertilized with animal manure.
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Affiliation(s)
- Hui Shi
- College of Natural Resources and Environment, South China Agricultural University, Wushan, 510642, Guangzhou, China
| | - Cuihua Bai
- College of Natural Resources and Environment, South China Agricultural University, Wushan, 510642, Guangzhou, China
| | - Donglin Luo
- College of Natural Resources and Environment, South China Agricultural University, Wushan, 510642, Guangzhou, China
| | - Wei Wang
- College of Natural Resources and Environment, South China Agricultural University, Wushan, 510642, Guangzhou, China
| | - Changmin Zhou
- College of Natural Resources and Environment, South China Agricultural University, Wushan, 510642, Guangzhou, China
| | - Andrew A Meharg
- Institute of Global Food Security, Queen's University Belfast, Belfast, BT9 7BL, UK
| | - Lixian Yao
- College of Natural Resources and Environment, South China Agricultural University, Wushan, 510642, Guangzhou, China.
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18
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Abstract
Amyloid aggregates are associated with several debilitating diseases, and there are numerous efforts to develop small molecule treatments against these diseases. One challenge associated with these efforts is determining protein binding site information for potential therapeutics because amyloid-forming proteins rapidly form oligomers and aggregates, making traditional protein structural analysis techniques challenging. Using β-2-microglobulin (β2m) as a model amyloid-forming protein along with two recently identified small molecule amyloid inhibitors (i.e., rifamycin SV and doxycycline), we demonstrate that covalent labeling and mass spectrometry (MS) can be used to map small-molecule binding sites for a rapidly aggregating protein. Specifically, three different covalent labeling reagents, namely diethylpyrocarbonate, 2,3-butanedione, and the reagent pair EDC/GEE, are used together to pinpoint the binding sites of rifamycin SV, doxycycline, and another molecule, suramin, which binds but does not inhibit Cu(II)-induced β2m amyloid formation. The labeling results reveal binding sites that are consistent with the known effects of these molecules on β2m amyloid formation and are in general agreement with molecular docking results. We expect that this combined covalent labeling approach will be applicable to other protein/small molecule systems that are difficult to study by traditional means.
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Affiliation(s)
- Tianying Liu
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Tyler M. Marcinko
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Patrick A. Kiefer
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Richard W. Vachet
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
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19
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Widyasari-Mehta A, Suwito HRKA, Kreuzig R. Laboratory testing on the removal of the veterinary antibiotic doxycycline during long-term liquid pig manure and digestate storage. Chemosphere 2016; 149:154-60. [PMID: 26855219 DOI: 10.1016/j.chemosphere.2016.01.094] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 01/21/2016] [Accepted: 01/23/2016] [Indexed: 05/23/2023]
Abstract
The veterinary antibiotic doxycycline (DOXY) is today frequently applied in conventional pig husbandry for the control of respiratory diseases. After the treatment, pigs excrete major amounts of DOXY as the unchanged active substance. Thus, DOXY residues were found in liquid manures and digestates of biogas plants at concentrations of mg kg(-1) dry weight. In order to assess the impact of field applications of contaminated manures and digestates on the entry of DOXY residues into arable and grassland soils, thorough information about the removal of DOXY during long-term storage of farm fertilizers is required. Since this aspect has been only less investigated for manures but not for digestates, first long-term storage simulation tests were performed at laboratory scale. Within the 170-d incubation periods under strictly anaerobic conditions, doxycycline was removed in liquid pig manure by 61% and in digestate by 76%. The calculated half-lives of 120 d and 91 d thus emphasized the persistence of doxycycline in both matrices. Due to the substance specific properties of DOXY, this removal was caused neither by mineralization, epimerization nor biotransformation. According to the high affinity of DOXY to manure and digestate solids, however, the formation of non-extractable residues has to be taken into account as the predominant concentration determining process. This was indicated by the sequential extraction procedure applied. Hence, these results confirmed that a full removal capacity for doxycycline cannot be reached through the long-term storage of farm fertilizers.
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Affiliation(s)
- Arum Widyasari-Mehta
- Technische Universität Braunschweig, Institut für Ökologische und Nachhaltige Chemie, Hagenring 30, 38106 Braunschweig, Germany
| | - Hanna Resti Kartika Ayu Suwito
- Technische Universität Braunschweig, Institut für Ökologische und Nachhaltige Chemie, Hagenring 30, 38106 Braunschweig, Germany
| | - Robert Kreuzig
- Technische Universität Braunschweig, Institut für Ökologische und Nachhaltige Chemie, Hagenring 30, 38106 Braunschweig, Germany.
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20
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van der Velden YU, Kleibeuker W, Harwig A, Klaver B, Siteur-van Rijnstra E, Frankin E, Berkhout B, Das AT. Construction of Nef-positive doxycycline-dependent HIV-1 variants using bicistronic expression elements. Virology 2015; 488:96-107. [PMID: 26615334 DOI: 10.1016/j.virol.2015.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/14/2015] [Accepted: 11/06/2015] [Indexed: 11/19/2022]
Abstract
Conditionally replicating HIV-1 variants that can be switched on and off at will are attractive tools for HIV research. We previously developed a genetically modified HIV-1 variant that replicates exclusively when doxycycline (dox) is administered. The nef gene in this HIV-rtTA variant was replaced with the gene encoding the dox-dependent rtTA transcriptional activator. Because loss of Nef expression compromises virus replication in primary cells and precludes studies on Nef function, we tested different approaches to restore Nef production in HIV-rtTA. Strategies that involved translation via an EMCV or synthetic internal ribosome entry site (IRES) failed because these elements were incompatible with efficient virus replication. Fusion protein approaches with the FMDV 2A peptide and human ubiquitin were successful and resulted in genetically-stable Nef-expressing HIV-rtTA strains that replicate more efficiently in primary T-cells and human immune system (HIS) mice than Nef-deficient variants, thus confirming the positive effect of Nef on in vivo virus replication.
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Affiliation(s)
- Yme U van der Velden
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Wendy Kleibeuker
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Alex Harwig
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Bep Klaver
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Esther Siteur-van Rijnstra
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Esmay Frankin
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Atze T Das
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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21
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Zaranyika MF, Dzomba P, Kugara J. Speciation and persistence of doxycycline in the aquatic environment: Characterization in terms of steady state kinetics. J Environ Sci Health B 2015; 50:908-918. [PMID: 26267779 DOI: 10.1080/03601234.2015.1067101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aim of the present work was to establish the kinetics for the degradation of doxycycline in the aquatic environment with a view to arriving at a kinetic model that can be used to predict the persistence of antibiotic with confidence. The degradation of doxycycline in both water and sediment phases of aquatic microcosm experiments, as well as in distilled water control experiments, was studied over a period of 90 days. An initial 21% loss due to adsorption by the sediment was observed in the microcosm experiment soon after charging. Biphasic zero-order linear rates of degradation, attributed to microbial degradation of the free and sediment or colloidal particle-adsorbed antibiotic, were observed for both water phase (2.3 × 10(-2) and 4.5 × 10(-3) μgg(-1) day(-1)) and sediment phase (7.9 × 10(-3) and 1.5 × 10(-3) μgg(-1) day(-1)) of the microcosm experiment. The covered distilled water control experiment exhibited a monophasic zero-order linear rate (1.9 × 10(-3) μgg(-1) day(-1)) attributed to hydrolysis, while the distilled water experiment exposed to natural light exhibited biphasic liner rates attributed to a combination of hydrolysis and photolysis (2.9 × 10(-3) μgg(-1) day(-1)) and to microbial degradation (9.8 × 10(-3) μgg(-1) day(-1)). A kinetic model that takes into account hydrolysis, photolysis, microbial degradation as well as sorption/desorption by colloidal and sediment particles is presented to account for the observed zero-order kinetics. The implications of the observed kinetics on the persistence of doxycycline in the aquatic environment are discussed.
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Affiliation(s)
- Mark F Zaranyika
- a Chemistry Department , Faculty of Science, University of Zimbabwe , Mount Pleasant, Harare , Zimbabwe
| | - Pamhidzai Dzomba
- a Chemistry Department , Faculty of Science, University of Zimbabwe , Mount Pleasant, Harare , Zimbabwe
| | - Jameson Kugara
- a Chemistry Department , Faculty of Science, University of Zimbabwe , Mount Pleasant, Harare , Zimbabwe
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22
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Legrand N, van der Velden GJ, Fang RHT, Douaisi M, Weijer K, Das AT, Blom B, Uittenbogaart CH, Berkhout B, Centlivre M. A doxycycline-dependent human immunodeficiency virus type 1 replicates in vivo without inducing CD4+ T-cell depletion. J Gen Virol 2012; 93:2017-2027. [PMID: 22647372 DOI: 10.1099/vir.0.042796-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A novel genetic approach for the control of virus replication was used for the design of a conditionally replicating human immunodeficiency virus (HIV) variant, HIV-rtTA. HIV-rtTA gene expression and virus replication are strictly dependent on the presence of a non-toxic effector molecule, doxycycline (dox), and thus can be turned on and off at will in a graded and reversible manner. The in vivo replication capacity, pathogenicity and genetic stability of this HIV-rtTA variant were evaluated in a humanized mouse model of haematopoiesis that harbours lymphoid and myeloid components of the human immune system (HIS). Infection of dox-fed BALB Rag/γc HIS (BRG-HIS) mice with HIV-rtTA led to the establishment of a productive infection without CD4(+) T-cell depletion. The virus did not show any sign of escape from dox control for up to 10 weeks after the onset of infection. No reversion towards a functional Tat-transactivating responsive (TAR) RNA element axis was observed, confirming the genetic stability of the HIV-rtTA variant in vivo. These results demonstrate the proof of concept that HIV-rtTA replicates efficiently in vivo. HIV-rtTA is a promising tool for fundamental research to study virus-host interactions in vivo in a controlled fashion.
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Affiliation(s)
- Nicolas Legrand
- Department of Cell Biology and Histology, Center for Immunology of Amsterdam (CIA), Academic Medical Center of the University of Amsterdam (AMC-UvA), Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Gisela J van der Velden
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center of the University of Amsterdam (AMC-UvA), Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Raphaël Ho Tsong Fang
- Microbiology, Immunology and Molecular Genetics, and Pediatrics, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, USA
| | - Marc Douaisi
- Microbiology, Immunology and Molecular Genetics, and Pediatrics, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, USA
| | - Kees Weijer
- Department of Cell Biology and Histology, Center for Immunology of Amsterdam (CIA), Academic Medical Center of the University of Amsterdam (AMC-UvA), Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Atze T Das
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center of the University of Amsterdam (AMC-UvA), Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Bianca Blom
- Department of Cell Biology and Histology, Center for Immunology of Amsterdam (CIA), Academic Medical Center of the University of Amsterdam (AMC-UvA), Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Christel H Uittenbogaart
- Microbiology, Immunology and Molecular Genetics, and Pediatrics, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, USA
| | - Ben Berkhout
- Department of Cell Biology and Histology, Center for Immunology of Amsterdam (CIA), Academic Medical Center of the University of Amsterdam (AMC-UvA), Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Mireille Centlivre
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center of the University of Amsterdam (AMC-UvA), Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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23
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Ward JE, Ren R, Toraldo G, Soohoo P, Guan J, O'Hara C, Jasuja R, Trinkaus-Randall V, Liao R, Connors LH, Seldin DC. Doxycycline reduces fibril formation in a transgenic mouse model of AL amyloidosis. Blood 2011; 118:6610-7. [PMID: 21998211 PMCID: PMC3242721 DOI: 10.1182/blood-2011-04-351643] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 09/22/2011] [Indexed: 12/17/2022] Open
Abstract
Systemic AL amyloidosis results from the aggregation of an amyloidogenic immunoglobulin (Ig) light chain (LC) usually produced by a plasma cell clone in the bone marrow. AL is the most rapidly fatal of the systemic amyloidoses, as amyloid fibrils can rapidly accumulate in tissues including the heart, kidneys, autonomic or peripheral nervous systems, gastrointestinal tract, and liver. Chemotherapy is used to eradicate the cellular source of the amyloidogenic precursor. Currently, there are no therapies that target the process of LC aggregation, fibril formation, or organ damage. We developed transgenic mice expressing an amyloidogenic λ6 LC using the cytomegalovirus (CMV) promoter to circumvent the disruption of B cell development by premature expression of recombined LC. The CMV-λ6 transgenic mice develop neurologic dysfunction and Congophilic amyloid deposits in the stomach. Amyloid deposition was inhibited in vivo by the antibiotic doxycycline. In vitro studies demonstrated that doxycycline directly disrupted the formation of recombinant LC fibrils. Furthermore, treatment of ex vivo LC amyloid fibrils with doxycycline reduced the number of intact fibrils and led to the formation of large disordered aggregates. The CMV-λ6 transgenic model replicates the process of AL amyloidosis and is useful for testing the antifibril potential of orally available agents.
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Affiliation(s)
- Jennifer Ellis Ward
- Amyloid Treatment and Research Program, and Department of Medicine, Medicine, Boston University School of Medicine and Boston Medical Center, Boston, MA 02118, USA
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24
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Kim S, Saadeldin IM, Choi WJ, Lee SJ, Lee WW, Kim BH, Han HJ, Bang DH, Lee BC, Jang G. Production of transgenic bovine cloned embryos using piggybac transposition. J Vet Med Sci 2011; 73:1453-7. [PMID: 21747215 DOI: 10.1292/jvms.11-0054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [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: 11/22/2022] Open
Abstract
Transgenic research on cattle embryos has been developed to date using viral or plasmid DNA delivery systems. In this study, a different gene delivery system, piggybac transposition, was employed to investigate if it can be applied for producing transgenic cattle embryos. Green or red fluorescent proteins (GFP or RFP) were transfected into donor fibroblasts, and then transfected donor cells were reprogrammed in enucleated oocytes through SCNT and developed into pre-implantation stage embryos. GFP was expressed in donor cells and in cloned embryos without any mosaicism. Induction of RFP expression was regulated by doxycycline treatment in donor fibroblasts and pre-implantational stage embryos. In conclusion, this study demonstrated that piggybac transposition could be a mean to deliver genes into bovine somatic cells or embryos for transgenic research.
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Affiliation(s)
- Su Kim
- Department of Theriogenology and Biotechnology, College of Veterinary Medicine and Research Institute, Seoul National University, Seoul 151–742, Republic of Korea
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25
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Hijosa-Valsero M, Fink G, Schlüsener MP, Sidrach-Cardona R, Martín-Villacorta J, Ternes T, Bécares E. Removal of antibiotics from urban wastewater by constructed wetland optimization. Chemosphere 2011; 83:713-719. [PMID: 21356542 DOI: 10.1016/j.chemosphere.2011.02.004] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 02/01/2011] [Accepted: 02/01/2011] [Indexed: 05/28/2023]
Abstract
Seven mesocosm-scale constructed wetlands (CWs), differing in their design characteristics, were set up in the open air to assess their efficiency to remove antibiotics from urban raw wastewater. A conventional wastewater treatment plant (WWTP) was simultaneously monitored. The experiment took place in autumn. An analytical methodology including HPLC-MS/MS was developed to measure antibiotic concentrations in the soluble water fraction, in the suspended solids fraction and in the WWTP sludge. Considering the soluble water fraction, the only easily eliminated antibiotics in the WWTP were doxycycline (61±38%) and sulfamethoxazole (60±26%). All the studied types of CWs were efficient for the removal of sulfamethoxazole (59±30-87±41%), as found in the WWTP, and, in addition, they removed trimethoprim (65±21-96±29%). The elimination of other antibiotics in CWs was limited by the specific system-configuration: amoxicillin (45±15%) was only eliminated by a free-water (FW) subsurface flow (SSF) CW planted with Typha angustifolia; doxycycline was removed in FW systems planted with T. angustifolia (65±34-75±40%), in a Phragmites australis-floating macrophytes system (62±31%) and in conventional horizontal SSF-systems (71±39%); clarithromycin was partially eliminated by an unplanted FW-SSF system (50±18%); erythromycin could only be removed by a P. australis-horizontal SSF system (64±30%); and ampicillin was eliminated by a T. angustifolia-floating macrophytes system (29±4%). Lincomycin was not removed by any of the systems (WWTP or CWs). The presence or absence of plants, the vegetal species (T. angustifolia or P. australis), the flow type and the CW design characteristics regulated the specific removal mechanisms. Therefore, CWs are not an overall solution to remove antibiotics from urban wastewater during cold seasons. However, more studies are needed to assess their ability in warmer periods and to determine the behaviour of full-scale systems.
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Affiliation(s)
- María Hijosa-Valsero
- Facultad de Ciencias Biológicas y Ambientales, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain.
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26
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Chang GH, Dividson A, Lin L, Wilson M, Siddell SG, Zhu QY. Establishment of the eukaryotic cell lines for inducible control of SARS-CoV nucleocapsid gene expression. Virol Sin 2010; 25:361-8. [PMID: 20960182 PMCID: PMC7091148 DOI: 10.1007/s12250-010-3124-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 04/30/2010] [Indexed: 01/13/2023] Open
Abstract
In order to establish the eukaryotic cell lines for inducible control of SARS-CoV nucleocapsid gene expression. The recombinant plasmid of pTRE-Tight-SARS-N was constructed by using the plasmid p8S as the PCR template which contains a cDNA clone covering the nucleocapsid gene of SARS-CoV HKU-39449. Restriction enzymes digestion and sequence analysis indicated the recombinant plasmid of pTRE-Tight-SARS-N contained the nucleocapsid gene with the optimized nucleotide sequence which will improve the translation efficiency. Positive cell clones were selected by cotransfecting pTRE-Tight-SARS-N with the linear marker pPUR to BHK-21 Tet-on cells in the presence of puromycin. A set of double-stable eukaryotic cell lines (BHK-Tet-SARS-N) with inducible control of the SARS-CoV neucleocapsid gene expression was identified by using SDS-PAGE and Western-blot analysis. The expression of SARS-CoV nucleocapsid protein was tightly regulated by the varying concentration of doxcycline in the constructed double-stable cell line. The constructed BHK-Tet-SARS-N cell strains will facilitate the rescue of SARS-CoV in vitro and the further reverse genetic research of SARS-CoV.
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Affiliation(s)
- Guo-Hui Chang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.
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27
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Crabtree MJ, Tatham AL, Hale AB, Alp NJ, Channon KM. Critical role for tetrahydrobiopterin recycling by dihydrofolate reductase in regulation of endothelial nitric-oxide synthase coupling: relative importance of the de novo biopterin synthesis versus salvage pathways. J Biol Chem 2009; 284:28128-28136. [PMID: 19666465 PMCID: PMC2788863 DOI: 10.1074/jbc.m109.041483] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 08/06/2009] [Indexed: 11/06/2022] Open
Abstract
Tetrahyrobiopterin (BH4) is a required cofactor for the synthesis of nitric oxide by endothelial nitric-oxide synthase (eNOS), and BH4 bioavailability within the endothelium is a critical factor in regulating the balance between NO and superoxide production by eNOS (eNOS coupling). BH4 levels are determined by the activity of GTP cyclohydrolase I (GTPCH), the rate-limiting enzyme in de novo BH4 biosynthesis. However, BH4 levels may also be influenced by oxidation, forming 7,8-dihydrobiopterin (BH2), which promotes eNOS uncoupling. Conversely, dihydrofolate reductase (DHFR) can regenerate BH4 from BH2, but the functional importance of DHFR in maintaining eNOS coupling remains unclear. We investigated the role of DHFR in regulating BH4 versus BH2 levels in endothelial cells and in cell lines expressing eNOS combined with tet-regulated GTPCH expression in order to compare the effects of low or high levels of de novo BH4 biosynthesis. Pharmacological inhibition of DHFR activity by methotrexate or genetic knockdown of DHFR protein by RNA interference reduced intracellular BH4 and increased BH2 levels resulting in enzymatic uncoupling of eNOS, as indicated by increased eNOS-dependent superoxide but reduced NO production. In contrast to the decreased BH4:BH2 ratio induced by DHFR knockdown, GTPCH knockdown greatly reduced total biopterin levels but with no change in BH4:BH2 ratio. In cells expressing eNOS with low biopterin levels, DHFR inhibition or knockdown further diminished the BH4:BH2 ratio and exacerbated eNOS uncoupling. Taken together, these data reveal a key role for DHFR in eNOS coupling by maintaining the BH4:BH2 ratio, particularly in conditions of low total biopterin availability.
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Affiliation(s)
- Mark J Crabtree
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Amy L Tatham
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Ashley B Hale
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Nicholas J Alp
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Keith M Channon
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom.
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28
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Zeng H, Horie K, Madisen L, Pavlova MN, Gragerova G, Rohde AD, Schimpf BA, Liang Y, Ojala E, Kramer F, Roth P, Slobodskaya O, Dolka I, Southon EA, Tessarollo L, Bornfeldt KE, Gragerov A, Pavlakis GN, Gaitanaris GA. An inducible and reversible mouse genetic rescue system. PLoS Genet 2008; 4:e1000069. [PMID: 18464897 PMCID: PMC2346557 DOI: 10.1371/journal.pgen.1000069] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Accepted: 04/10/2008] [Indexed: 12/13/2022] Open
Abstract
Inducible and reversible regulation of gene expression is a powerful approach for uncovering gene function. We have established a general method to efficiently produce reversible and inducible gene knockout and rescue in mice. In this system, which we named iKO, the target gene can be turned on and off at will by treating the mice with doxycycline. This method combines two genetically modified mouse lines: a) a KO line with a tetracycline-dependent transactivator replacing the endogenous target gene, and b) a line with a tetracycline-inducible cDNA of the target gene inserted into a tightly regulated (TIGRE) genomic locus, which provides for low basal expression and high inducibility. Such a locus occurs infrequently in the genome and we have developed a method to easily introduce genes into the TIGRE site of mouse embryonic stem (ES) cells by recombinase-mediated insertion. Both KO and TIGRE lines have been engineered for high-throughput, large-scale and cost-effective production of iKO mice. As a proof of concept, we have created iKO mice in the apolipoprotein E (ApoE) gene, which allows for sensitive and quantitative phenotypic analyses. The results demonstrated reversible switching of ApoE transcription, plasma cholesterol levels, and atherosclerosis progression and regression. The iKO system shows stringent regulation and is a versatile genetic system that can easily incorporate other techniques and adapt to a wide range of applications. We describe a technology for the creation of inducible and reversible gene inactivation in mice. It combines two genetically modified mouse lines: a knock-out line with a tetracycline transactivator replacing the endogenous target gene, and a line in which a tetracycline-inducible cDNA of the target gene has been inserted into a specific genomic locus. A critical component of this system is the unique chromosomal loci we have identified and engineered that offer a platform for easy insertion of any gene of interest for tightly controlled expression. Because of its simple binary nature, allowing independent modification of each of the two components and possibility of use in a high-throughput mode, we believe that our system will be useful for multiple applications, such as introducing mutant or humanized form of the target gene as well as functional manipulating tools. We have applied this technology to the Apolipoprotein E (ApoE) gene and have demonstrated that: a) the expression of ApoE is strictly dependent on the presence of doxycycline, a tetracycline group antibiotic, in the mouse diet, b) in the absence of doxycycline (ApoE repressed) atherosclerotic plaques are formed, confirming the importance of ApoE in the process, and c) upon re-induction of ApoE in the animals with doxicyclin, atherosclerosis regressed.
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Affiliation(s)
- Hongkui Zeng
- Omeros Corporation, Seattle, Washington, United States of America
| | - Kyoji Horie
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - Linda Madisen
- Omeros Corporation, Seattle, Washington, United States of America
| | - Maria N. Pavlova
- Omeros Corporation, Seattle, Washington, United States of America
| | - Galina Gragerova
- Omeros Corporation, Seattle, Washington, United States of America
| | - Alex D. Rohde
- Omeros Corporation, Seattle, Washington, United States of America
| | - Brian A. Schimpf
- Omeros Corporation, Seattle, Washington, United States of America
| | - Yuqiong Liang
- Omeros Corporation, Seattle, Washington, United States of America
| | - Ethan Ojala
- Omeros Corporation, Seattle, Washington, United States of America
| | - Farah Kramer
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - Patricia Roth
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - Olga Slobodskaya
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - Io Dolka
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - Eileen A. Southon
- Neural Development Section, Mouse Cancer Genetics Program, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - Lino Tessarollo
- Neural Development Section, Mouse Cancer Genetics Program, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - Karin E. Bornfeldt
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | | | - George N. Pavlakis
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland, United States of America
- * E-mail: (GGA); (GNP)
| | - George A. Gaitanaris
- Omeros Corporation, Seattle, Washington, United States of America
- * E-mail: (GGA); (GNP)
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Li Q, Omori Y, Nishikawa Y, Yoshioka T, Yamamoto Y, Enomoto K. Cytoplasmic accumulation of connexin32 protein enhances motility and metastatic ability of human hepatoma cells in vitro and in vivo. Int J Cancer 2007; 121:536-46. [PMID: 17372902 DOI: 10.1002/ijc.22696] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [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
Connexins have long been believed to suppress tumour development during carcinogenesis by exerting gap junctional intercellular communication (GJIC). Although GJIC is abrogated in hepatocellular carcinoma (HCC), connexin32 (Cx32) protein tends to remain expressed in cytoplasm, but not in cell-cell contact areas; thus, it is incapable of forming gap junctions. Hypothesising that cytoplasmic Cx32 protein that has accumulated in HCC should have its proper functions, which are independent of GJIC, we established an inducible expression system of Cx32 in human HuH7 HCC cells, which were unable to support the formation of Cx32-mediated gap junctions, so that Cx32 protein could be overexpressed by doxycycline (Dox) withdrawal. Although the established clone HuH7 Tet-off Cx32 cells exhibited a 4-fold increase in Cx32 expression after Dox withdrawal, none of them were dye-coupled, and Cx32 protein was retained in the Golgi apparatus. However, the proliferation rate of the HuH7 Tet-off Cx32 cells was significantly higher in the Dox-free medium than in the Dox-supplemented one. Transwell assays also revealed that Dox withdrawal enhanced serum-stimulated motility and invasiveness into Matrigel of the HuH7 Tet-off Cx32 cells. Furthermore, when HuH7 Tet-off Cx32 cells were xenografted into the liver of SCID mice, only the mice to which no Dox was administered developed metastatic lesions, indicating that overexpression of cytoplasmic Cx32 protein induced metastasis of HuH7 cells. Our results suggest that, while Cx32-mediated GJIC suppresses the development of HCCs, cytoplasmic Cx32 protein exerts effects favourable for HCC progression, such as invasion and metastasis, once the cells have acquired a malignant phenotype.
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Affiliation(s)
- Qingchang Li
- Department of Pathology and Immunology, Akita University School of Medicine, 1-1-1 Hondo, Akita, Japan
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30
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Ke N, Zhou D, Chatterton JE, Liu G, Chionis J, Zhang J, Tsugawa L, Lynn R, Yu D, Meyhack B, Wong-Staal F, Li QX. A new inducible RNAi xenograft model for assessing the staged tumor response to mTOR silencing. Exp Cell Res 2006; 312:2726-34. [PMID: 16765945 DOI: 10.1016/j.yexcr.2006.05.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Revised: 04/28/2006] [Accepted: 05/01/2006] [Indexed: 12/20/2022]
Abstract
Human xenograft tumor models are widely used for efficacy evaluation of potential cancer targets. siRNA is usually stably introduced into tumor cells prior to transplantation. However, silencing of the cancer therapeutic target usually results in reduced cell growth/survival in vitro and/or failure to establish tumors in vivo, thus hindering tumor response-based efficacy evaluation. The present study explored a new tumor response model based on regulated RNAi, which is more relevant from a clinical standpoint. As a proof of principle, an inducible lentiviral RNAi vector was used to silence the known cancer therapeutic target mTOR upon induction with Doxycycline (DOX). The responses to DOX-induced mTOR silencing were tested both in vitro and in vivo for prostate cancer PC3 models. Significant reduction in cancer cell survival was observed due to cell cycle arrest and apoptosis when mTOR silencing was induced in vitro. mTOR silencing also caused tumor regression for the early-staged PC3 tumors (100% tumor regressed and 45% became tumor-free). The advanced-staged tumors also demonstrated significant responses (100% regressed). Therefore, our results demonstrate the powerful utility of this new inducible xenograft tumor model for efficacy evaluation of cancer targets, and it provides a direct in vivo efficacy validation of mTOR as a cancer therapeutic target.
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Affiliation(s)
- Ning Ke
- Immusol, Inc., 10790 Roselle Street, San Diego, CA 92121, USA
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31
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Lee CZ, Yao JS, Huang Y, Zhai W, Liu W, Guglielmo BJ, Lin E, Yang GY, Young WL. Dose-response effect of tetracyclines on cerebral matrix metalloproteinase-9 after vascular endothelial growth factor hyperstimulation. J Cereb Blood Flow Metab 2006; 26:1157-64. [PMID: 16395286 DOI: 10.1038/sj.jcbfm.9600268] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Brain arteriovenous malformations (BAVMs) are a potentially life-threatening disorder. Matrix metalloproteinase (MMP)-9 activity was greatly increased in BAVM tissue specimens. Doxycycline was shown to decrease cerebral MMP-9 activities and angiogenesis induced by vascular endothelial growth factor (VEGF). In the present study, we determined the dose-response effects of doxycycline and minocycline on cerebral MMP-9 using our mouse model with VEGF focal hyperstimulation delivered with adenoviral vector (AdVEGF) in the brain. Mice were treated with doxycycline or minocycline, respectively, at 1, 5, 10, 30, 50, or 100 mg/kg/day through drinking water for 1 week. Our results have shown that MMP-9 messenger ribonucleic acid (mRNA) expression was inhibited by doxycycline starting at 10 mg/kg/day (P<0.02). Minocycline showed more potent inhibition on MMP-9 mRNA expression, starting at 1 (P<0.005) and further at more than 30 (P<0.001) mg/kg/day. At the enzymatic activity level, doxycycline started to suppress MMP-9 activity at 5 mg/kg/day (P<0.001), while minocycline had an effect at a lower dose, 1 mg/kg/day (P<0.02). The inhibition of cerebral MMP-9 mRNA and activity were highly correlated with drug levels in the brain tissue. We also assessed the potential relevant signaling pathway in vitro to elucidate the mechanisms underlying the MMP-9 inhibition by tetracyclines. In vitro, minocycline, but not doxycycline, inhibits MMP-9, at least in part, via the extracellular signaling-related kinase 1/2 (ERK1/2)-mediated pathway. This study provided the evidence that the tetracyclines inhibit stimulated cerebral MMP-9 at multiple levels and are effective at very low doses, offering great potential for therapeutic use.
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MESH Headings
- Animals
- Anti-Bacterial Agents/metabolism
- Anti-Bacterial Agents/pharmacology
- Blotting, Western
- Brain/metabolism
- Brain Chemistry/drug effects
- Cell Movement/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- Doxycycline/metabolism
- Doxycycline/pharmacology
- Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors
- Gelatin/metabolism
- Intracranial Arteriovenous Malformations/enzymology
- Male
- Matrix Metalloproteinase 9/metabolism
- Mice
- Minocycline/metabolism
- Minocycline/pharmacology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Stimulation, Chemical
- Tetracyclines/metabolism
- Tetracyclines/pharmacology
- Vascular Endothelial Growth Factor A/pharmacology
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Affiliation(s)
- Chanhung Z Lee
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, 94110, USA
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Naik K, Pittman I, Wolfe A, Miller RS, Radovick S, Wondisford FE. A novel technique for temporally regulated cell type-specific Cre expression and recombination in the pituitary gonadotroph. J Mol Endocrinol 2006; 37:63-9. [PMID: 16901924 DOI: 10.1677/jme.1.02053] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Inducing tissue-specific genetic alterations under temporal control allows for the analysis of gene function in particular cell types at specified points in time. We have generated a system for tetracycline-controlled expression of Cre recombinase in mice using the unique CreTeR vector. The gonadotroph-specific bovine alpha-subunit (Balpha) promoter fragment was subcloned into the CreTeR vector, creating a technique for highly regulated expression of Cre recombinase exclusively in pituitary gonadotrophs. Control of Cre recombinase in the CreTeR vector was demonstrated in LbetaT2 pituitary cell lines, where Cre protein was detected in cells treated with doxycycline, but not in untreated cells. In transgenic mice, Cre was expressed in pituitary gonadotrophs of mice treated with doxycycline, but not in non-pituitary tissues or in transgenic mice not treated with doxycycline. We demonstrated Cre expression in the gonadotroph by immunostaining showing co-localization of Cre recombinase with the beta-subunit of LH (LH-beta). Furthermore, by crossing Balpha/CreTeR with R26R mice, we were able to demonstrate functional recombination within pituitary gonadotrophs, detected by lacZ expression. The Balpha/CreTeR mice described here can be used to study the function of virtually any gene in the gonadotroph; in particular, this will be useful in studying genes, which may have distinct roles in development and in the adult.
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Affiliation(s)
- Karuna Naik
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
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33
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Stieger K, Le Meur G, Lasne F, Weber M, Deschamps JY, Nivard D, Mendes-Madeira A, Provost N, Martin L, Moullier P, Rolling F. Long-term doxycycline-regulated transgene expression in the retina of nonhuman primates following subretinal injection of recombinant AAV vectors. Mol Ther 2006; 13:967-75. [PMID: 16442848 DOI: 10.1016/j.ymthe.2005.12.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 12/13/2005] [Accepted: 12/13/2005] [Indexed: 10/25/2022] Open
Abstract
Adeno-associated viral gene therapy has shown promise for the treatment of inherited and acquired retinal disorders. In most applications, regulation of expression is a critical concern for both safety and efficacy. The purpose of our study was to evaluate the ability of the tetracycline-regulatable system to establish long-term transgene regulation in the retina of nonhuman primates. Three rAAV vectors expressing the tetracycline-dependent transactivator (rtTA) under the control of either the ubiquitous CAG promoter or the specific RPE65 promoter (AAV2/5.CAG.TetOn.epo, AAV2/4.CAG.TetOn.epo, and AAV2/4.RPE65.TetOn.epo) were generated and administered subretinally to seven macaques. We demonstrated that repeated inductions of transgene expression in the nonhuman primate retina can be achieved using a Tet-inducible system via rAAV vector administration over a long period (2.5 years). Maximum erythropoietin (EPO) secretion in the anterior chamber depends upon the rAAV serotype and the nature of the promoter driving rtTA expression. We observed that the EPO isoforms produced in the retina differ from one another based on the transduced cell type of origin within the retina and also differ from both the physiological EPO isoforms and the isoforms produced by AAV-transduced skeletal muscle.
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Affiliation(s)
- Knut Stieger
- INSERM UMR U649, CHU-Hotel Dieu, Bât. J. Monnet, 30 Avenue J. Monnet, 44035 Nantes Cedex 01, France
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34
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Zhou X, Vink M, Klaver B, Verhoef K, Marzio G, Das AT, Berkhout B. The genetic stability of a conditional live HIV-1 variant can be improved by mutations in the Tet-On regulatory system that restrain evolution. J Biol Chem 2006; 281:17084-17091. [PMID: 16627480 DOI: 10.1074/jbc.m513400200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [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: 11/06/2022] Open
Abstract
Live attenuated human immunodeficiency virus type 1 (HIV-1) vaccines are considered unsafe because more quickly replicating pathogenic virus variants may evolve after vaccination. As an alternative vaccine approach, we have previously presented a doxycycline (dox)-dependent HIV-1 variant that was constructed by incorporating the tetracycline-inducible gene expression system (Tet-On system) into the viral genome. Replication of this HIV-rtTA variant is driven by the dox-inducible transcriptional activator rtTA and can be switched on and off at will. A large scale evolution study was performed to test the genetic stability of this conditional live vaccine candidate. In several long term cultures, we selected for HIV-rtTA variants that no longer required dox for replication. These evolved variants acquired a typical amino acid substitution either at position 19 or 37 in the rtTA protein. Both mutations caused rtTA activity and viral replication in the absence of dox. We designed a novel rtTA variant with a higher genetic barrier toward these undesired evolutionary routes. The corresponding HIV-rtTA variant did not lose dox control in long term cultures, demonstrating its improved genetic stability.
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Affiliation(s)
- Xue Zhou
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Monique Vink
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Bep Klaver
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Koen Verhoef
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Giuseppe Marzio
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Atze T Das
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Ben Berkhout
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
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Richter K, Wirta V, Dahl L, Bruce S, Lundeberg J, Carlsson L, Williams C. Global gene expression analyses of hematopoietic stem cell-like cell lines with inducible Lhx2 expression. BMC Genomics 2006; 7:75. [PMID: 16600034 PMCID: PMC1459142 DOI: 10.1186/1471-2164-7-75] [Citation(s) in RCA: 17] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Accepted: 04/06/2006] [Indexed: 12/13/2022] Open
Abstract
Background Expression of the LIM-homeobox gene Lhx2 in murine hematopoietic cells allows for the generation of hematopoietic stem cell (HSC)-like cell lines. To address the molecular basis of Lhx2 function, we generated HSC-like cell lines where Lhx2 expression is regulated by a tet-on system and hence dependent on the presence of doxycyclin (dox). These cell lines efficiently down-regulate Lhx2 expression upon dox withdrawal leading to a rapid differentiation into various myeloid cell types. Results Global gene expression of these cell lines cultured in dox was compared to different time points after dox withdrawal using microarray technology. We identified 267 differentially expressed genes. The majority of the genes overlapping with HSC-specific databases were those down-regulated after turning off Lhx2 expression and a majority of the genes overlapping with those defined as late progenitor-specific genes were the up-regulated genes, suggesting that these cell lines represent a relevant model system for normal HSCs also at the level of global gene expression. Moreover, in situ hybridisations of several genes down-regulated after dox withdrawal showed overlapping expression patterns with Lhx2 in various tissues during embryonic development. Conclusion Global gene expression analysis of HSC-like cell lines with inducible Lhx2 expression has identified genes putatively linked to self-renewal / differentiation of HSCs, and function of Lhx2 in organ development and stem / progenitor cells of non-hematopoietic origin.
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Affiliation(s)
- Karin Richter
- Umeå Center for Molecular Medicin, Umeå Universitet, 90187 Umeå, Sweden
| | - Valtteri Wirta
- School of Biotechnology, KTH, Royal Institute of Technology, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Lina Dahl
- Umeå Center for Molecular Medicin, Umeå Universitet, 90187 Umeå, Sweden
| | - Sara Bruce
- School of Biotechnology, KTH, Royal Institute of Technology, AlbaNova University Center, 10691 Stockholm, Sweden
- Department of Biosciences at Novum, Karolinska Institutet, 14157 Huddinge, Sweden
| | - Joakim Lundeberg
- School of Biotechnology, KTH, Royal Institute of Technology, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Leif Carlsson
- Umeå Center for Molecular Medicin, Umeå Universitet, 90187 Umeå, Sweden
| | - Cecilia Williams
- School of Biotechnology, KTH, Royal Institute of Technology, AlbaNova University Center, 10691 Stockholm, Sweden
- Department of Biosciences at Novum, Karolinska Institutet, 14157 Huddinge, Sweden
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36
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Välimäki VV, Moritz N, Yrjans JJ, Vuorio E, Aro HT. Effect of zoledronic acid on incorporation of a bioceramic bone graft substitute. Bone 2006; 38:432-43. [PMID: 16338190 DOI: 10.1016/j.bone.2005.09.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2005] [Revised: 09/09/2005] [Accepted: 09/09/2005] [Indexed: 11/25/2022]
Abstract
Many osteoporotic fracture patients are candidates for concurrent treatment with bisphosphonates and bioceramic bone graft substitutes. Osteopromotive silica-based bioactive glasses are known to induce accelerated local bone turnover and adjunct antiresorptive agents, such as zoledronic acid, may affect the process. The current study examined the effect of adjunct zoledronic acid therapy on bioactive glass incorporation. In Harlan Sprague-Dawley rats (n = 80), a standardized region of the proximal tibia was subjected to ablation of local bone marrow and filled with bioactive glass (BG) microspheres. Experimental animals received zoledronic acid (1.5 mug/kg, s.c., once a week, started 1 week before surgery) or doxycycline (a metalloproteinase inhibitor) (33 mg/kg, daily gavage) as a control agent. BG incorporation and geometric bone properties were followed by sequential pQCT imaging. The final outcome at 8 weeks was analyzed by digital radiography, histomorphometry, BEI-SEM, EDXA and muCT. The mRNA levels of markers for bone resorption (cathepsin K, TRACP, MMP-9, MMP-13) and synthesis (type I, II, III collagens, osteocalcin, osteonectin, osteopontin) were measured for determination of local bone turnover. Bones filled with BG microspheres produced 2.5-fold more intramedullary new bone than controls with bone marrow ablation only, but the BG filling delayed the recovery of pQCT strength strain index (SSI) of the bones. Adjunct therapy with zoledronic acid enhanced new bone formation on BG microspheres and particularly improved the SSI values of the BG-filled bones (P < 0.05). The zoledronic acid therapy alone (without BG filling) produced the highest amount of intramedullary new bone (6-fold more than in unfilled controls, P < 0.001) but did not show a similar benefit in SSI. The analyses of mRNA expression confirmed high local bone turnover in all bones with BG filling. At the 9th week of zoledronic acid treatment, bones with and without BG filling showed increased mRNA levels of bone resorption markers and decreased mRNA levels of markers for synthesis, indicating that a corrective resorption process was already in progress in response to massive accumulation of medullary new bone at earlier stages of the therapy. Adjunct antiresorptive therapy seems to be beneficial for incorporation of bioactive glass microspheres and does not block local natural remodeling processes. In the current model, the therapy even resulted in favorable remodeling of the tubular bone structure.
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Affiliation(s)
- Ville-Valtteri Välimäki
- Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, University of Turku, Kiinamyllynkatu 4-8, FIN-20520 Turku, Finland
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Grover J, Roughley PJ. Generation of a transgenic mouse in which Cre recombinase is expressed under control of the type II collagen promoter and doxycycline administration. Matrix Biol 2005; 25:158-65. [PMID: 16386413 DOI: 10.1016/j.matbio.2005.11.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Revised: 11/07/2005] [Accepted: 11/09/2005] [Indexed: 11/26/2022]
Abstract
The ability to generate tissue-specific ablation of gene expression has been extremely useful in connective tissue biology, as it can potentially overcome the early embryonic lethal phenotype often associated with universal gene knockout. The value of tissue-specific knockouts can be enhanced by also allowing gene ablation to occur at specific times during development, growth or aging. In the present work a transgenic mouse has been generated in which expression of Cre recombinase is under control of both the type II collagen promoter to allow cartilage-specific expression and a doxycycline response element to permit temporal control of expression. This mouse has been crossed with the Rosa26R reporter mouse, which possesses a floxed repressor element associated with a lacZ transgene, in order to validate the functional efficacy of the conditionally expressed Cre. The results demonstrate that excision of the floxed element can be achieved specifically in cartilage at different times during embryonic and juvenile development. The conditional Cre transgenic mouse should be a valuable tool to all interested in skeletal development.
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Affiliation(s)
- Judy Grover
- Genetics Unit, Shriners Hospital for Children, 1529 Cedar Avenue, Montreal, Quebec, Canada, H3G 1A6
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Lu S, Yao Y, Cheng X, Mitchell S, Leng S, Meng S, Gallagher JW, Shelness GS, Morris GS, Mahan J, Frase S, Mansbach CM, Weinberg RB, Black DD. Overexpression of apolipoprotein A-IV enhances lipid secretion in IPEC-1 cells by increasing chylomicron size. J Biol Chem 2005; 281:3473-83. [PMID: 16338933 DOI: 10.1074/jbc.m502501200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Intestinal apolipoprotein A-IV expression is highly regulated by dietary lipid in newborn swine, suggesting a role in lipid absorption. Constitutive overexpression of apoA-IV in newborn swine enterocytes enhances basolateral secretion of triacylglycerol (TG) in TG-rich lipoproteins 4.9-fold (Lu, S., Yao, Y., Meng, S., Cheng, X., and Black, D. D. (2002) J. Biol. Chem. 277, 31929-31937). To investigate the mechanism of this enhancement, IPEC-1 cells were transfected with a tetracycline-regulatable expression system (Tet-On). In cells incubated with oleic acid, a dose response relationship was observed between medium doxycycline concentration and basolateral apoA-IV and TG secretion. Similarly regulated expression of apoA-I did not enhance lipid secretion. The mean diameter of TG-rich lipoproteins secreted from doxycycline-treated cells was larger than from untreated cells (87.0 nm versus 53.4 nm). Basolateral apoB secretion decreased. Using the same expression system, full-length human apoA-IV (376 amino acids); a "pig-like" human apoA-IV, lacking the C-terminal EQQQ repeats (361 amino acids); and a "chicken-like" apoA-IV, further truncated to 343 amino acids, were expressed in IPEC-1 cells. With increasing protein secretion, cells expressing the full-length human apoA-IV displayed a 2-fold increase in TG secretion; in sharp contrast, cells expressing the pig-like human apoA-IV displayed a 25-fold increase in TG secretion and a 27-fold increase in lipoprotein diameter. When human apoA-IV was further truncated to yield a chicken-like protein, TG secretion was inhibited. We conclude that overexpression of swine apoA-IV enhances basolateral TG secretion in a dose-dependent manner by increasing the size of secreted lipoproteins. These data suggest that the region in the human apoA-IV protein from residues 344 to 354 is critical to its ability to enhance lipid secretion, perhaps by enabling the packaging of additional core TG into chylomicron particles. The EQQQ-rich region may play an inhibitory or modulatory role in chylomicron packaging in humans.
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MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Newborn
- Apolipoproteins/chemistry
- Apolipoproteins A/biosynthesis
- Apolipoproteins A/physiology
- Blotting, Western
- Cell Line
- Chickens
- Chylomicrons/chemistry
- Cloning, Molecular
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Doxycycline/metabolism
- Doxycycline/pharmacology
- Electrophoresis, Polyacrylamide Gel
- Humans
- Immunoprecipitation
- Intestinal Mucosa/metabolism
- Intestines/cytology
- Lipid Metabolism
- Lipids/chemistry
- Lipoproteins/metabolism
- Microscopy, Electron
- Microscopy, Electron, Transmission
- Molecular Sequence Data
- Mutation
- Oleic Acid/chemistry
- Oleic Acid/metabolism
- Protein Structure, Tertiary
- RNA/metabolism
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Swine
- Tetracycline/pharmacology
- Transcriptional Activation
- Triglycerides/metabolism
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Affiliation(s)
- Song Lu
- Children's Foundation Research Center at Le Bonheur Children's Medical Center and Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee 38103, USA
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39
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Abstract
The clearance of prions from the brain was investigated in bigenic mice designated Tg(tTA : PrP(+/0))3, in which expression of the cellular prion protein (PrP(C)) was regulated by oral doxycycline administration. With suppression of PrP(C) expression, the incubation time for RML prions was prolonged almost threefold from approximately 150 to approximately 430 days. To determine the clearance rate of disease-causing PrP(Sc), bigenic mice were given oral doxycycline beginning 98 days after inoculation with RML prions and sacrificed at various time points over the subsequent 56 days. The half-life (t1/2) for PrP(Sc) was approximately 1.5 days in mouse brain, in reasonable agreement with the apparent t1/2 of 30 h that was determined in a separate study for scrapie-infected mouse neuroblastoma (ScN2a) cells in culture. Both protease-sensitive and -resistant conformers of PrP(Sc) were cleared at the same rate. The t1/2 value for PrP(C) clearance from brain was approximately 18 h, which was considerably longer than the t1/2 of 5 h found in ScN2a cells. The capability of the brain to clear prions raises the possibility that PrP(Sc) is normally made at low levels and continually cleared, and that PrP(Sc) may have a function in cellular metabolism. Moreover, these bigenic mice make it possible to determine both components of PrP(Sc) accumulation, i.e. the rates of formation and clearance, for various strains of prions exhibiting different incubation times.
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Affiliation(s)
- Jiri G Safar
- Department of Neurology, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
- Institute for Neurodegenerative Diseases, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
| | - Stephen J DeArmond
- Department of Pathology, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
- Institute for Neurodegenerative Diseases, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
| | - Katarzyna Kociuba
- Institute for Neurodegenerative Diseases, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
| | - Camille Deering
- Institute for Neurodegenerative Diseases, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
| | - Svetlana Didorenko
- Institute for Neurodegenerative Diseases, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
| | | | - Stanley B Prusiner
- Department of Biochemistry and Biophysics, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
- Department of Neurology, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
- Institute for Neurodegenerative Diseases, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
| | - Patrick Tremblay
- Department of Neurology, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
- Institute for Neurodegenerative Diseases, University of California, 513 Parnassus Ave, San Francisco, CA 94143, USA
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40
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Yu HMI, Liu B, Chiu SY, Costantini F, Hsu W. Development of a unique system for spatiotemporal and lineage-specific gene expression in mice. Proc Natl Acad Sci U S A 2005; 102:8615-20. [PMID: 15941831 PMCID: PMC1150815 DOI: 10.1073/pnas.0500124102] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have developed an advanced method for conditional gene expression in mice that integrates the Cre-mediated and tetracycline-dependent expression systems. An rtTA gene, preceded by a loxP-flanked STOP sequence, was inserted into the ROSA26 locus to create a R26STOPrtTA mouse strain. When the STOP sequence is excised by Cre-mediated recombination, the rtTA is expressed in the Cre-expressing cells and all of their derivatives. Therefore, cell type-, tissue-, or lineage-specific expression of rtTA is achieved by the use of an appropriate Cre transgenic strain. In mice also carrying a target gene under the control of the tetracycline response element, inducible expression of the target gene is temporally regulated by administration of doxycycline. Our results demonstrate that this universal system is uniquely suited for spatiotemporal and lineage-specific gene expression in an inducible fashion. Gene expression can be manipulated in specific cell types and lineages with a flexibility that is difficult to achieve with conventional methods.
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Affiliation(s)
- Hsiao-Man Ivy Yu
- Center for Oral Biology, Department of Biomedical Genetics, Abs Institute of Biomedical Sciences, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Avenue, Box 611, Rochester, NY 14642, USA
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41
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Richard P, Pollard H, Lanctin C, Bello-Roufaï M, Désigaux L, Escande D, Pitard B. Inducible production of erythropoietin using intramuscular injection of block copolymer/DNA formulation. J Gene Med 2005; 7:80-6. [PMID: 15468192 DOI: 10.1002/jgm.631] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [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: 11/06/2022] Open
Abstract
BACKGROUND We have previously shown that intramuscular injection of plasmid DNA formulated with a non-ionic amphiphile synthetic vector [poly(ethylene oxide)(13)-poly(propylene oxide)(30)-poly(ethylene oxide)(13) block copolymer; PE6400] increases reporter gene expression compared with naked DNA. We have now investigated this simple non-viral formulation for production of secreted proteins from the mouse skeletal muscle. METHODS Plasmids encoding either constitutive human secreted alkaline phosphatase or murine erythropoietin inducible via a Tet-on system were formulated with PE6400 and intramuscularly injected into the mouse tibial anterior muscle. RESULTS PE6400/DNA formulation led to an increased amount of recombinant alkaline phosphatase secreted from skeletal muscle as compared with naked DNA. In the presence of doxycycline, a single injection of 10 microg plasmid encoding inducible murine erythropoietin formulated with PE6400 significantly increased the hematocrit, whereas the same amount of DNA in the absence of PE6400 had no effect. The increase in the hematocrit was stable for 42 days. The tetracycline-inducible promoter permitted pharmacological control of hematocrit level after DNA intramuscular injection. However, 4 months post-injection the hematocrit returned to its pre-injection value, even in the presence of doxycycline. This phenomenon was likely caused by an immune response against the tetracycline-activated transcription factor. CONCLUSIONS Intramuscular injection of plasmid DNA formulated with PE6400 provides an efficient and simple method for secretion and production of non-muscle proteins.
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Affiliation(s)
- Peggy Richard
- L'Institut du Thorax, Institut National de la Santé et de la Recherche Médicale, Inserm U533, Faculté de Médecine, 44000 Nantes, France
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42
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Matthess Y, Kappel S, Spänkuch B, Zimmer B, Kaufmann M, Strebhardt K. Conditional inhibition of cancer cell proliferation by tetracycline-responsive, H1 promoter-driven silencing of PLK1. Oncogene 2005; 24:2973-80. [PMID: 15735719 DOI: 10.1038/sj.onc.1208472] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Revised: 11/15/2004] [Accepted: 12/13/2004] [Indexed: 11/08/2022]
Abstract
RNA interference (RNAi) is a powerful tool for studying gene function. We developed an inducible genetic element for short interfering RNA-mediated gene silencing. This system uses a tetracycline (Tet)-responsive derivative of the H1 promoter and the Tet repressor (TetR) for conditional expression of short hairpin RNA (shRNA) in HeLa cells. Promoter constructs were generated, which contain the Tet operator (TetO) derived from a prokaryotic Tet resistance transposon upstream and/or downstream of the TATA box. To quantify the response of controllable transcription units for shRNA expression, we examined the functional activity of polo-like kinase 1 (PLK1), a key component of mitotic progression, that is overexpressed in many human tumors. Cotransfection of plasmids for the expression of TetR and shRNA/PLK1 under the control of an H1 promoter-variant carrying TetO upstream of the TATA box did not alter PLK1 expression and proliferation properties of HeLa cells in the absence of doxycycline. Addition of the antibiotic led to marked downregulation of endogenous PLK1 accompanied by strong inhibition of cellular proliferation. Our data indicate that an inducible transcription system for shRNAs based on the human H1 promoter could be a versatile tool for controlled gene silencing in vitro.
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Affiliation(s)
- Yves Matthess
- Department of Gynecology and Obstetrics, School of Medicine, JW Goethe-University, Theodor-Stern-Kai 7, Haus 15, Frankfurt 60590, Germany
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43
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Murphy LC, Peng B, Lewis A, Davie JR, Leygue E, Kemp A, Ung K, Vendetti M, Shiu R. Inducible upregulation of oestrogen receptor-beta1 affects oestrogen and tamoxifen responsiveness in MCF7 human breast cancer cells. J Mol Endocrinol 2005; 34:553-66. [PMID: 15821116 DOI: 10.1677/jme.1.01688] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
To investigate the effect of altered oestrogen receptor (ER)alpha and ERbeta expression on oestrogen and anti-oestrogen action in breast cancer, we have stably expressed an inducible ERbeta1 in MCF7 breast cancer cells. Stably expressing clones were isolated and over-expression of ERbeta1 correlated with increased levels of specific radiolabelled oestradiol (E2) binding. Increased ERbeta1 did not affect endogenous levels of ERalpha but increased progesterone receptor (PR) levels. Over-expression of ERbeta1 reduced growth responses to E2 in contrast to little if any effect of over-expression of ERalpha. In oestrogen-replete conditions, over-expression of ERbeta1 but not ERalpha reduced proliferation. Over-expression of ERbeta1 did not result in anti-oestrogen resistance but was associated with increased sensitivity to 4-hydroxytamoxifen. Our results suggested that over-expression of ERbeta1 in the presence of an endogenously expressed ERalpha was associated with tamoxifen sensitivity but may negatively modulate ERalpha-mediated growth. However, not all ERalpha activities were inhibited since endogenous PR expression was increased by both ERalpha and ERbeta1 over-expression. These data paralleled those seen in some in vivo studies showing a relationship between PR and ERbeta expression as well as ERbeta expression and tamoxifen sensitivity of ER-positive breast cancer patients. These models are relevant and will be useful for dissecting the role of ERbeta1 expression in ER-positive breast cancer.
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Affiliation(s)
- L C Murphy
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada.
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44
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Hosono T, Mizuguchi H, Katayama K, Xu ZL, Sakurai F, Ishii-Watabe A, Kawabata K, Yamaguchi T, Nakagawa S, Mayumi T, Hayakawa T. Adenovirus vector-mediated doxycycline-inducible RNA interference. Hum Gene Ther 2005; 15:813-9. [PMID: 15319038 DOI: 10.1089/1043034041648462] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [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] Open
Abstract
RNA interference (RNAi) is a powerful tool for the knockdown of gene expression. Here, we report on the development of an adenovirus (Ad) vector-mediated doxycycline (Dox)-inducible small interfering RNA (siRNA) expression system. We used this siRNA system to control the expression of p53 and c-Myc in human cancer cells. Coinfection of Ad vectors containing the siRNA expression system under the control of the Dox-inducible H1 promoter and Ad vectors expressing a tetracycline repressor inhibited the expression levels of p53 and c-Myc in a dose-dependent manner with both Dox and viral dose. Regulated silencing of p53 and c-Myc expression was obtained. Because an Ad vector-mediated inducible RNAi system can efficiently transduce a variety of cell types in vitro and in vivo, and the degree of loss of gene expression can be modulated according to the dose of Dox, this expression system should be a useful tool for both basic research on the analysis of gene function and therapeutic applications of RNAi.
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Affiliation(s)
- Tetsuji Hosono
- Division of Cellular and Gene Therapy Products, National Institute of Health Sciences, Tokyo 158-8501, Japan
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45
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García RA, Pantazatos DP, Gessner CR, Go KV, Woods VL, Villarreal FJ. Molecular interactions between matrilysin and the matrix metalloproteinase inhibitor doxycycline investigated by deuterium exchange mass spectrometry. Mol Pharmacol 2005; 67:1128-36. [PMID: 15665254 DOI: 10.1124/mol.104.006346] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Matrix metalloproteinases (MMPs) play an essential role in normal and pathological extracellular matrix degradation. Deuterium exchange mass spectrometry (DXMS) was used to localize the binding regions of the broad-spectrum MMP inhibitor doxycycline on the active form of matrilysin (residues 95-267) and to assess alterations in structure induced by doxycycline binding. DXMS analyses of inhibitor-bound versus inhibitor-free forms of matrilysin reveal two primary sites of reduced hydrogen/deuterium exchange (residues 145-153; residues 193-204) that flank the structural zinc binding site. Equilibrium dialysis studies of doxycycline-matrilysin binding yielded a K(d) of 73 microM with a binding stoichiometry of 2.3 inhibitor molecules per protein, which compares well with DXMS results that show principal reduction in deuterium exchange at two sites. Lesser changes in deuterium exchange evident at the amino and carboxyl termini are attributed to inhibitor-induced structural fluctuations. Tryptophan fluorescence quenching experiments of matrilysin with potassium iodide suggest changes in conformation induced by doxycycline binding. In the presence of doxycycline, tryptophan quenching is reduced by approximately 17% relative to inhibitor-free matrilysin. Examination of the X-ray crystal structure of matrilysin shows that the doxycycline-binding site at residues 193 to 204 is positioned within the structural metal center of matrilysin, adjacent to the structural zinc atom and near both calcium atoms. These results suggest a mode of matrilysin inhibition by doxycycline that could involve interactions with the structural zinc atom and/or calcium atoms within the structural metal center of the protein.
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Affiliation(s)
- Ricardo A García
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, BSB 0613J, La Jolla, CA 92093, USA
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46
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Gafni Y, Pelled G, Zilberman Y, Turgeman G, Apparailly F, Yotvat H, Galun E, Gazit Z, Jorgensen C, Gazit D. Gene therapy platform for bone regeneration using an exogenously regulated, AAV-2-based gene expression system. Mol Ther 2004; 9:587-95. [PMID: 15093189 DOI: 10.1016/j.ymthe.2003.12.009] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2002] [Accepted: 12/17/2003] [Indexed: 11/15/2022] Open
Abstract
Viral delivery of the therapeutic gene bone morphogenetic protein-2 (BMP-2) is a promising approach for bone regeneration. The human parvovirus adeno-associated virus (AAV) type 2 is considered one of the most encouraging viral vector systems because of its high transduction rates and biosafety ratings. Bone morphogenetic protein-2 is a highly potent osteoinductive protein, which induces bone formation in vivo and osteogenic differentiation in vitro. The exogenous regulation of BMP-2 expression in bone-regenerating sites is required to control BMP-2 protein secretion, thus promoting safe and controlled bone formation and regeneration. We have therefore constructed a dual-construct vector for the recombinant AAV (rAAV)-based recombinant human BMP-2 (rhBMP-2) gene delivery system, which is regulated by the tetracycline-sensitive promoter (TetON). Each vector was encapsidated separately, yielding two recombinant viruses. We evaluated the efficiency of rAAV-hBMP-2 to induce bone formation in ectopic and orthotopic sites. Doxycycline (Dox), an analogue of tetracycline, was orally administered to mice via their drinking water to induce rhBMP-2 expression. Bone formation was measured using quantitative imaging-microcomputerized tomography and cooled charge-coupled device imaging-to detect osteogenic activity at the cellular level, detecting osteocalcin expression. The rAAV-hBMP-2-treated mice that were given Dox demonstrated bone formation in both in vivo models compared to none in mice prevented from receiving Dox. Thus, the Tet-regulated rAAV-hBMP-2 vector is an effective means of induction and regulation of bone regeneration and repair.
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Affiliation(s)
- Yossi Gafni
- Skeletal Biotechnology Laboratory, Hebrew University-Hadassah Medical Center, Ein Kerem, P.O. Box 12272, Jerusalem 91120, Israel
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Steffner RJ, Wu L, Powers AC, May JM. Ascorbic acid recycling by cultured beta cells: effects of increased glucose metabolism. Free Radic Biol Med 2004; 37:1612-21. [PMID: 15477012 DOI: 10.1016/j.freeradbiomed.2004.07.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 07/20/2004] [Accepted: 07/29/2004] [Indexed: 10/26/2022]
Abstract
Ascorbic acid is necessary for optimal insulin secretion from pancreatic islets. We evaluated ascorbate recycling and whether it is impaired by increased glucose metabolism in the rat beta-cell line INS-1. INS-1 cells, engineered with the potential for overexpression of glucokinase under the control of a tetracycline-inducible gene expression system, took up and reduced dehydroascorbic acid to ascorbate in a concentration-dependent manner that was optimal in the presence of physiologic D-glucose concentrations. Ascorbate uptake did not affect intracellular GSH concentrations. Whereas depletion of GSH in culture to levels about 25% of normal also did not affect the ability of the cells to reduce dehydroascorbic acid, more severe acute GSH depletion to less than 10% of normal levels did impair dehydroascorbic acid reduction. Culture of inducible cells in 11.8 mM D-glucose and doxycycline for 48 h enhanced glucokinase activity, increased glucose utilization, abolished D-glucose-dependent insulin secretion, and increased generation of reactive oxygen species. The latter may have contributed to subsequent decreases in the ability of the cells both to maintain intracellular ascorbate and to recycle it from dehydroascorbic acid. Cultured beta cells have a high capacity to recycle ascorbate, but this is sensitive to oxidant stress generated by increased glucose metabolism due to culture in high glucose concentrations and increased glucokinase expression. Impaired ascorbate recycling as a result of increased glucose metabolism may have implications for the role of ascorbate in insulin secretion in diabetes mellitus and may partially explain glucose toxicity in beta cells.
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Affiliation(s)
- Robert J Steffner
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, USA
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48
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Fujioka S, Niu J, Schmidt C, Sclabas GM, Peng B, Uwagawa T, Li Z, Evans DB, Abbruzzese JL, Chiao PJ. NF-kappaB and AP-1 connection: mechanism of NF-kappaB-dependent regulation of AP-1 activity. Mol Cell Biol 2004; 24:7806-19. [PMID: 15314185 PMCID: PMC507000 DOI: 10.1128/mcb.24.17.7806-7819.2004] [Citation(s) in RCA: 319] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1) transcription factors regulate many important biological and pathological processes. Activation of NF-kappaB is regulated by the inducible phosphorylation of NF-kappaB inhibitor IkappaB by IkappaB kinase. In contrast, Fos, a key component of AP-1, is primarily transcriptionally regulated by serum responsive factors (SRFs) and ternary complex factors (TCFs). Despite these different regulatory mechanisms, there is an intriguing possibility that NF-kappaB and AP-1 may modulate each other, thus expanding the scope of these two rapidly inducible transcription factors. To determine whether NF-kappaB activity is involved in the regulation of fos expression in response to various stimuli, we analyzed activity of AP-1 and expression of fos, fosB, fra-1, fra-2, jun, junB, and junD, as well as AP-1 downstream target gene VEGF, using MDAPanc-28 and MDAPanc-28/IkappaBalphaM pancreatic tumor cells and wild-type, IKK1-/-, and IKK2-/- murine embryonic fibroblast cells. Our results show that elk-1, a member of TCFs, is one of the NF-kappaB downstream target genes. Inhibition of NF-kappaB activity greatly decreased expression of elk-1. Consequently, the reduced level of activated Elk-1 protein by extracellular signal-regulated kinase impeded constitutive, serum-, and superoxide-inducible c-fos expression. Thus, our study revealed a distinct and essential role of NF-kappaB in participating in the regulation of elk-1, c-fos, and VEGF expression.
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Affiliation(s)
- Shuichi Fujioka
- Department of Surgical Oncology, Box 107, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA
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49
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Pizzo DP, Paban V, Coufal NG, Gage FH, Thal LJ. Long-term production of choline acetyltransferase in the CNS after transplantation of fibroblasts modified with a regulatable vector. ACTA ACUST UNITED AC 2004; 126:1-13. [PMID: 15207910 DOI: 10.1016/j.molbrainres.2004.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2004] [Indexed: 10/26/2022]
Abstract
A rat fibroblast cell line was modified to contain the Drosophila choline acetyltransferase (ChAT) cDNA under the control of a tetracycline-regulated system. Several clonal lines were assessed in vitro and in vivo to establish the optimal clone for gene therapy experiments. The influence of in vitro cell density on ChAT expression was compared to biological activity detected after grafting to the rat brain. While each clone had different ChAT activity patterns, all clones had low activity immediately post-grafting which increased over time, reaching a plateau between 1 and 2 months which was maintained for at least 1 year. The clones expressed a high basal ChAT activity level in vitro that was repressed in a dose- and time-dependent manner with doxycycline (DOX) treatment. In the absence of DOX, high levels of ChAT activity were maintained for at least 2 months in vitro. DOX induced a rapid and strong (200-fold) suppression of ChAT activity within 48 h. A dose-response curve indicated that the fibroblasts were very sensitive to low concentrations of DOX (ED50 12 pg/ml). Removal of DOX led to a derepression of ChAT activity within 2 days. These cells will be useful for ex vivo gene therapy of the cholinergic system.
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Affiliation(s)
- Donald P Pizzo
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92023, USA
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50
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Firsov AA, Vostrov SN, Lubenko IY, Portnoy YA, Zinner SH. Prevention of the selection of resistant Staphylococcus aureus by moxifloxacin plus doxycycline in an in vitro dynamic model: an additive effect of the combination. Int J Antimicrob Agents 2004; 23:451-6. [PMID: 15120722 DOI: 10.1016/j.ijantimicag.2003.11.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2003] [Accepted: 11/12/2003] [Indexed: 11/27/2022]
Abstract
Twenty-four hour ratios of area under the curve (AUC(24)) to MIC of 200-240 h providing quinolone concentrations above the mutant prevention concentration (MPC) protected from enrichment of resistant Staphylococcus aureus in our recent study that simulated the pharmacokinetics of moxifloxacin, gatifloxacin, levofloxacin and ciprofloxacin. These protective AUC(24)/MICs might also be achieved by using antibiotic combinations, assuming additive effects of two anti-staphylococcal agents. To test this hypothesis, changes in S. aureus susceptibility were examined in a dynamic model that simulates 5-day treatment with moxifloxacin and doxycycline, alone and in combination at sub-optimal AUC(24)/MICs of each agent. Significant increases in MIC were observed with monotherapy where moxifloxacin or doxycycline concentrations fell into the mutant selection window (MSW) for more than 80% of the dosing interval (AUC(24)/MIC 60 h). Less pronounced changes in MIC occurred when the summed concentrations of moxifloxacin (AUC(24)/MIC 30 and 60 h) and doxycycline (AUC(24)/MIC 30 and 60 h) were inside the MSWs for the individual drugs for 30-50% of the dosing interval. No loss in susceptibility was found at moxifloxacin or doxycycline AUC(24)/MIC 170 h combined with the smaller AUC(24)/MIC (60 h) of the second compound. These data suggest that the total AUC(24)/MIC of 230 h might protect against S. aureus resistance. As this value is very close to that predicted in monotherapy with moxifloxacin (220 h), an additive protective effect of quinolone+doxycycline on the selection of resistant S. aureus is proposed. The use of drug combinations may be useful for restricting the enrichment of resistant mutants with agents whose clinically achievable AUC(24)/MICs do not provide concentrations above the MPC.
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Affiliation(s)
- Alexander A Firsov
- Department of Pharmacokinetics and Pharmacodynamics, Gause Institute of New Antibiotics, Russian Academy of Medical Sciences, 11 Bolshaya Pirogovskaya Street, Moscow 119021, Russia.
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