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Callahan V, Hawks S, Crawford MA, Lehman CW, Morrison HA, Ivester HM, Akhrymuk I, Boghdeh N, Flor R, Finkielstein CV, Allen IC, Weger-Lucarelli J, Duggal N, Hughes MA, Kehn-Hall K. The Pro-Inflammatory Chemokines CXCL9, CXCL10 and CXCL11 Are Upregulated Following SARS-CoV-2 Infection in an AKT-Dependent Manner. Viruses 2021; 13:1062. [PMID: 34205098 PMCID: PMC8226769 DOI: 10.3390/v13061062] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [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: 05/05/2021] [Revised: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 12/22/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible RNA virus that is the causative agent of the Coronavirus disease 2019 (COVID-19) pandemic. Patients with severe COVID-19 may develop acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) and require mechanical ventilation. Key features of SARS-CoV-2 induced pulmonary complications include an overexpression of pro-inflammatory chemokines and cytokines that contribute to a 'cytokine storm.' In the current study an inflammatory state in Calu-3 human lung epithelial cells was characterized in which significantly elevated transcripts of the immunostimulatory chemokines CXCL9, CXCL10, and CXCL11 were present. Additionally, an increase in gene expression of the cytokines IL-6, TNFα, and IFN-γ was observed. The transcription of CXCL9, CXCL10, IL-6, and IFN-γ was also induced in the lungs of human transgenic angiotensin converting enzyme 2 (ACE2) mice infected with SARS-CoV-2. To elucidate cell signaling pathways responsible for chemokine upregulation in SARS-CoV-2 infected cells, small molecule inhibitors targeting key signaling kinases were used. The induction of CXCL9, CXCL10, and CXCL11 gene expression in response to SARS-CoV-2 infection was markedly reduced by treatment with the AKT inhibitor GSK690693. Samples from COVID-19 positive individuals also displayed marked increases in CXCL9, CXCL10, and CXCL11 transcripts as well as transcripts in the AKT pathway. The current study elucidates potential pathway specific targets for reducing the induction of chemokines that may be contributing to SARS-CoV-2 pathogenesis via hyperinflammation.
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Affiliation(s)
- Victoria Callahan
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (V.C.); (N.B.); (R.F.)
| | - Seth Hawks
- Department of Biomedical Science and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; (S.H.); (C.W.L.); (H.A.M.); (I.A.); (I.C.A.); (J.W.-L.); (N.D.)
| | - Matthew A. Crawford
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA; (M.A.C.); (M.A.H.)
| | - Caitlin W. Lehman
- Department of Biomedical Science and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; (S.H.); (C.W.L.); (H.A.M.); (I.A.); (I.C.A.); (J.W.-L.); (N.D.)
| | - Holly A. Morrison
- Department of Biomedical Science and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; (S.H.); (C.W.L.); (H.A.M.); (I.A.); (I.C.A.); (J.W.-L.); (N.D.)
| | - Hannah M. Ivester
- Graduate Program in Translational Biology, Medicine and Health, Virginia Polytechnic Institute and State University, Roanoke, VA 24061, USA;
| | - Ivan Akhrymuk
- Department of Biomedical Science and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; (S.H.); (C.W.L.); (H.A.M.); (I.A.); (I.C.A.); (J.W.-L.); (N.D.)
| | - Niloufar Boghdeh
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (V.C.); (N.B.); (R.F.)
| | - Rafaela Flor
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (V.C.); (N.B.); (R.F.)
| | - Carla V. Finkielstein
- Integrated Cellular Responses Laboratory, Department of Biological Sciences and Center for Drug Discovery, Fralin Biomedical Research Institute, Virginia Polytechnic Institute and State University, Roanoke, VA 24016, USA;
| | - Irving Coy Allen
- Department of Biomedical Science and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; (S.H.); (C.W.L.); (H.A.M.); (I.A.); (I.C.A.); (J.W.-L.); (N.D.)
- Virginia Tech Carilion School of Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24016, USA
- Center for Zoonotic and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - James Weger-Lucarelli
- Department of Biomedical Science and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; (S.H.); (C.W.L.); (H.A.M.); (I.A.); (I.C.A.); (J.W.-L.); (N.D.)
- Center for Zoonotic and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Nisha Duggal
- Department of Biomedical Science and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; (S.H.); (C.W.L.); (H.A.M.); (I.A.); (I.C.A.); (J.W.-L.); (N.D.)
- Center for Zoonotic and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Molly A. Hughes
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA; (M.A.C.); (M.A.H.)
| | - Kylene Kehn-Hall
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, VA 20110, USA; (V.C.); (N.B.); (R.F.)
- Department of Biomedical Science and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; (S.H.); (C.W.L.); (H.A.M.); (I.A.); (I.C.A.); (J.W.-L.); (N.D.)
- Center for Zoonotic and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
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Lin SC, Lehman CW, Stewart AK, Panny L, Bracci N, Wright JLC, Paige M, Strangman WK, Kehn-Hall K. Homoseongomycin, a compound isolated from marine actinomycete bacteria K3-1, is a potent inhibitor of encephalitic alphaviruses. Antiviral Res 2021; 191:105087. [PMID: 33965437 DOI: 10.1016/j.antiviral.2021.105087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/25/2021] [Accepted: 05/03/2021] [Indexed: 01/09/2023]
Abstract
Marine microorganisms have been a resource for novel therapeutic drugs for decades. In addition to anticancer drugs, the drug acyclovir, derived from a marine sponge, is FDA-approved for the treatment of human herpes simplex virus-1 infections. Most alphaviruses that are infectious to terrestrial animals and humans, such as Venezuelan and eastern equine encephalitis viruses (VEEV and EEEV), lack efficient antiviral drugs and it is imperative to develop these remedies. To push the discovery and development of anti-alphavirus compounds forward, this study aimed to isolate and screen for potential antiviral compounds from cultured marine microbes originating from the marine environment. Compounds from marine microbes were of interest as they are prolific producers of bioactive compounds across the spectrum of human diseases and infections. Homoseongomycin, an actinobacteria isolated from a marine sponge displayed impressive activity against VEEV from a total of 76 marine bioactive products. The 50% effective concentration (EC50) for homoseongomycin was 8.6 μM for suppressing VEEV TC-83 luciferase reporter virus replication. Homoseongomycin was non-toxic up to 50 μM and partially rescued cells from VEEV induced cell death. Homoseongomycin exhibited highly efficient antiviral activity with a reduction of VEEV infectious titers by 8 log10 at 50 μM. It also inhibited EEEV replication with an EC50 of 1.2 μM. Mechanism of action studies suggest that homoseongomycin affects both early and late stages of the viral life cycle. Cells treated with 25 μM of homoseongomycin had a ~90% reduction in viral entry. In comparison, later stages showed a more robust reduction in infectious titers (6 log10) and VEEV extracellular viral RNA levels (4 log10), but a lesser impact on intracellular viral RNA levels (1.5 log10). In sum, this work demonstrates that homoseongomycin is a potential anti-VEEV and anti-EEEV compound due to its low cytotoxicity and potent antiviral activity.
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Affiliation(s)
- Shih-Chao Lin
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, 20110, USA; Bachelor Degree in Marine Biotechnology, College of Life Sciences, National Taiwan Ocean University, Keelung, 202301, Taiwan
| | - Caitlin W Lehman
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, 20110, USA; Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Allison K Stewart
- Molecular Education, Technology and Research Innovation Center, North Carolina State University, Raleigh, NC, 27607, USA
| | - Lauren Panny
- Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Nicole Bracci
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, 20110, USA; Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Jeffrey L C Wright
- Department of Chemistry and Biochemistry, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, 28403, USA
| | - Mikell Paige
- Department of Chemistry and Biochemistry, George Mason University, Manassas, VA, 20110, USA
| | - Wendy K Strangman
- Department of Chemistry and Biochemistry, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, 28403, USA
| | - Kylene Kehn-Hall
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, 20110, USA; Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA; Center for Zoonotic and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
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Wu CS, Lin SC, Li S, Chiang YC, Bracci N, Lehman CW, Tang KT, Lin CC. Phloretin alleviates dinitrochlorobenzene-induced dermatitis in BALB/c mice. Int J Immunopathol Pharmacol 2021; 34:2058738420929442. [PMID: 32571120 PMCID: PMC7313336 DOI: 10.1177/2058738420929442] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Atopic dermatitis (AD) is a chronic inflammatory disease of the skin that substantially affects a patient's quality of life. While steroids are the most common therapy used to temporally alleviate the symptoms of AD, effective and nontoxic alternatives are urgently needed. In this study, we utilized a natural, plant-derived phenolic compound, phloretin, to treat allergic contact dermatitis (ACD) on the dorsal skin of mice. In addition, the effectiveness of phloretin was evaluated using a mouse model of ACD triggered by 2,4-dinitrochlorobenzene (DNCB). In our experimental setting, phloretin was orally administered to BALB/c mice for 21 consecutive days, and then, the lesions were examined histologically. Our data revealed that phloretin reduced the process of epidermal thickening and decreased the infiltration of mast cells into the lesion regions, subsequently reducing the levels of histamine and the pro-inflammatory cytokines interleukin (IL)-6, IL-4, thymic stromal lymphopoietin (TSLP), interferon-γ (IFN-γ) and IL-17A in the serum. These changes were associated with lower serum levels after phloretin treatment. In addition, we observed that the mitogen-activated protein kinase (MAPK) and NF-κB pathways in the dermal tissues of the phloretin-treated rodents were suppressed compared to those in the AD-like skin regions. Furthermore, phloretin appeared to limit the overproliferation of splenocytes in response to DNCB stimulation, reducing the number of IFN-γ-, IL-4-, and IL-17A-producing CD4+ T cells in the spleen back to their normal ranges. Taken together, we discovered a new therapeutic role of phloretin using a mouse model of DNCB-induced ACD, as shown by the alleviated AD-like symptoms and the reversed immunopathological effects. Therefore, we believe that phloretin has the potential to be utilized as an alternative therapeutic agent for treating AD.
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Affiliation(s)
- Chieh-Shan Wu
- Department of Dermatology, Kaohsiung Veterans General Hospital, Kaohsiung
| | - Shih-Chao Lin
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, VA, USA
| | - Shiming Li
- Hubei Key Laboratory for Processing & Application of Catalytic Materials, College of Chemistry & Chemical Engineering, Huanggang Normal University, Huanggang, China
| | - Yu-Chih Chiang
- Department of Restaurant, Hotel and Institutional Management, College of Human Ecology, Fu Jen Catholic University, New Taipei City
| | - Nicole Bracci
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, VA, USA
| | - Caitlin W Lehman
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, VA, USA
| | - Kuo-Tung Tang
- Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung
| | - Chi-Chien Lin
- Department of Life Sciences, Institute of Biomedical Sciences, The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung.,Department of Medical Research, China Medical University Hospital, Taichung.,Department of Medical Research, Taichung Veterans General Hospital, Taichung
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Lehman CW, Kehn-Hall K, Aggarwal M, Bracci NR, Pan HC, Panny L, Lamb RA, Lin SC. Resveratrol Inhibits Venezuelan Equine Encephalitis Virus Infection by Interfering with the AKT/GSK Pathway. Plants (Basel) 2021; 10:plants10020346. [PMID: 33673026 PMCID: PMC7918260 DOI: 10.3390/plants10020346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/03/2021] [Accepted: 02/07/2021] [Indexed: 12/21/2022]
Abstract
The host proteins Protein Kinase B (AKT) and glycogen synthase kinase-3 (GSK-3) are associated with multiple neurodegenerative disorders. They are also important for the replication of Venezuelan equine encephalitis virus (VEEV), thereby making the AKT/GSK-3 pathway an attractive target for developing anti-VEEV therapeutics. Resveratrol, a natural phytochemical, has been shown to substantially inhibit the AKT pathway. Therefore, we attempted to explore whether it exerts any antiviral activity against VEEV. In this study, we utilized green fluorescent protein (GFP)- and luciferase-encoding recombinant VEEV to determine the cytotoxicity and antiviral efficacy via luciferase reporter assays, flow cytometry, and immunofluorescent assays. Our results indicate that resveratrol treatment is capable of inhibiting VEEV replication, resulting in increased viability of Vero and U87MG cells as well as reduced virion production and viral RNA contents within host cells for at least 48 h with a single treatment. Furthermore, the suppression of apoptotic signaling adaptors, caspase-3, caspase-7, and annexin V may also be implicated in resveratrol-mediated antiviral activity. We found that decreased phosphorylation of the AKT/GSK-3 pathway, mediated by resveratrol, can be triggered during the early stages of VEEV infection, suggesting that resveratrol disrupts the viral replication cycle and consequently promotes cell survival. Finally, molecular docking and dynamics simulation studies revealed that resveratrol can directly bind to VEEV glycoproteins, which may interfere with virus attachment and entry. In conclusion, our results suggest that resveratrol exerts inhibitory activity against VEEV infection and upon further modification could be a useful compound to study in neuroprotective research and veterinary sciences.
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Affiliation(s)
- Caitlin W. Lehman
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; (C.W.L.); (K.K.-H.); (N.R.B.); (L.P.)
| | - Kylene Kehn-Hall
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; (C.W.L.); (K.K.-H.); (N.R.B.); (L.P.)
| | - Megha Aggarwal
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA; (M.A.); (R.A.L.)
- Howard Hughes Medical Institute, Northwestern University, Evanston, IL 60208, USA
| | - Nicole R. Bracci
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; (C.W.L.); (K.K.-H.); (N.R.B.); (L.P.)
| | - Han-Chi Pan
- National Center Animal Laboratory, National Applied Research Laboratories, Taipei 11599, Taiwan;
| | - Lauren Panny
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; (C.W.L.); (K.K.-H.); (N.R.B.); (L.P.)
| | - Robert A. Lamb
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA; (M.A.); (R.A.L.)
- Howard Hughes Medical Institute, Northwestern University, Evanston, IL 60208, USA
| | - Shih-Chao Lin
- Bachelor Degree Program in Marine Biotechnology, College of Life Sciences, National Taiwan Ocean University, 2 Pei-Ning Rd., Keelung 202301, Taiwan
- Correspondence:
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Lin SC, Lin CC, Li S, Lin WY, Lehman CW, Bracci NR, Tsai SW. Alleviation of Collagen-Induced Arthritis by Crotonoside through Modulation of Dendritic Cell Differentiation and Activation. Plants (Basel) 2020; 9:plants9111535. [PMID: 33182776 PMCID: PMC7698099 DOI: 10.3390/plants9111535] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 12/22/2022]
Abstract
Crotonoside, a guanosine analog originally isolated from Croton tiglium, is reported to be a potent tyrosine kinase inhibitor with immunosuppressive effects on immune cells. Due to its potential immunotherapeutic effects, we aimed to evaluate the anti-arthritic activity of crotonoside and explore its immunomodulatory properties in alleviating the severity of arthritic symptoms. To this end, we implemented the treatment of crotonoside on collagen-induced arthritic (CIA) DBA/1 mice and investigated its underlying mechanisms towards pathogenic dendritic cells (DCs). Our results suggest that crotonoside treatment remarkably improved clinical arthritic symptoms in this CIA mouse model as indicated by decreased pro-inflammatory cytokine production in the serum and suppressed expression of co-stimulatory molecules, CD40, CD80, and MHC class II, on CD11c+ DCs from the CIA mouse spleens. Additionally, crotonoside treatment significantly reduced the infiltration of CD11c+ DCs into the synovial tissues. Our in vitro study further demonstrated that bone marrow-derived DCs (BMDCs) exhibited lower yield in numbers and expressed lower levels of CD40, CD80, and MHC-II when incubated with crotonoside. Furthermore, LPS-stimulated mature DCs exhibited limited capability to prime antigen-specific CD4+ and T-cell proliferation, cytokine secretions, and co-stimulatory molecule expressions when treated with crotonoside. Our pioneer study highlights the immunotherapeutic role of crotonoside in the alleviation of the CIA via modulation of pathogenic DCs, thus creating possible applications of crotonoside as an immunosuppressive agent that could be utilized and further explored in treating autoimmune disorders in the future.
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Affiliation(s)
- Shih-Chao Lin
- Bachelor Degree Program in Marine Biotechnology, National Taiwan Ocean University, Keelung 202301, Taiwan;
| | - Chi-Chien Lin
- Institute of Biomedical Science, The iEGG and Animal Biotechnology Center, National Chung-Hsing University, Taichung 402204, Taiwan; (C.-C.L.); (W.-Y.L.)
- Department of Medical Research, China Medical University Hospital, Taichung 404, Taiwan
- Department of Medical Research, Taichung Veterans General Hospital, Taichung 40705, Taiwan
- Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Shiming Li
- Hubei Key Laboratory for Processing and Application of Catalytic Materials, College of Chemistry and Chemical Engineering, Huanggang Normal University, Hubei 438000, China;
| | - Wan-Yi Lin
- Institute of Biomedical Science, The iEGG and Animal Biotechnology Center, National Chung-Hsing University, Taichung 402204, Taiwan; (C.-C.L.); (W.-Y.L.)
| | - Caitlin W. Lehman
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24063, USA; (C.W.L.); (N.R.B.)
| | - Nicole R. Bracci
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24063, USA; (C.W.L.); (N.R.B.)
| | - Sen-Wei Tsai
- Department of Physical Medicine and Rehabilitation, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan
- Department of Physical Medicine and Rehabilitation, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan
- Correspondence:
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Abstract
OBJECTIVE To compare the healing results between platelet-rich plasma (PRP) and platelet-derived patches versus traditional advanced wound dressings in patients with chronic wounds. METHOD Patients with and without diabetes were divided into two groups, each of which received either PRP patch treatments or the advanced wound dressings. All wounds were cleaned, debrided and assessed by physicians. The data were analysed and represented as mean ± standard deviation (SD). Student's t-test was used to calculate the significance of differences between both groups. Values of p<0.05 were considered statistically significant. RESULTS Patients with and without diabetes receiving PRP patch treatments saw improvement in wound healing in two weeks (p=0.0083). Patients with diabetes who received platelet-derived patch treatment and PRP injection experienced wound size reduction to <25% of the original area by the fourth week of treatment, and >90% of the subjects had wounds of <10% their original size in the last three weeks of the trial. Conversely, the wound area in the control subjects receiving traditional advanced wound dressings remained at 25-50% of their original size from the fourth week of treatment to the end of the trial. The healing process of the PRP patch experimental group was statistically significant compared with the control group (p<0.0001). CONCLUSION Combining treatments of PRP injections and platelet-derived patches significantly improved the healing outcomes of patients with chronic wounds, most notably in patients with diabetes, when compared with a traditional treatment of advanced wound dressings.
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Affiliation(s)
- Hsin-Chung Tsai
- Department of Surgery, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan; Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Caitlin W Lehman
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, US
| | - Chuan-Mu Chen
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
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Chuang CH, Cheng YC, Lin SC, Lehman CW, Wang SP, Chen DY, Tsai SW, Lin CC. Atractylodin Suppresses Dendritic Cell Maturation and Ameliorates Collagen-Induced Arthritis in a Mouse Model. J Agric Food Chem 2019; 67:6773-6784. [PMID: 31154759 DOI: 10.1021/acs.jafc.9b01163] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The aim of this study was to evaluate the immunomodulatory effects of atractylodin, a polyethylene alkyne, on the maturation of bone marrow-derived dendritic cells (BM-DC) as well as its antirheumatic effect on collagen-induced arthritis (CIA) in DBA/1 mice. Our results indicate that atractylodin effectively suppressed the secretion of pro-inflammatory cytokines, expression of costimulatory molecules, and p38 MAPK, ERK, and NF-κBp65 signaling pathways in LPS-incubated dendritic cells (DCs). Additionally, the proliferation and cytokine secretion (IFN-γ and IL-17A) of CD8+ and CD4+ T cells were reduced. In a murine CIA model, intraperitoneal injection of atractylodin significantly alleviated the severity of the disease progression, as indicated by reduced paw swelling, clinical arthritis scores, and pathological changes of joint tissues. In addition, the overall proliferation of T cells stimulated by type II collagen and the abundance of Th1 and Th17 in the spleens were also significantly decreased with atractylodin treatments. Furthermore, atractylodin significantly downregulated the expression levels of CD40, CD80, and CD86 of DCs in the spleens. In conclusion, this study shows for the first time that atractylodin has potential to manipulate the maturation of BM-DCs and should be further explored as a therapeutic agent in the treatment of rheumatoid arthritis (RA).
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Affiliation(s)
- Cheng Hsuan Chuang
- Institute of Biomedical Science , National Chung-Hsing University , Taichung 402 , Taiwan
| | - Yu-Chieh Cheng
- Institute of Biomedical Science , National Chung-Hsing University , Taichung 402 , Taiwan
- Department of Orthopaedics , Tungs' Taichung Metro Harbor Hospital , Taichung 433 , Taiwan
| | - Shih-Chao Lin
- National Center for Biodefense and Infectious Diseases, School of Systems Biology , George Mason University , Manassas , Virginia 20110 , United States
| | - Caitlin W Lehman
- National Center for Biodefense and Infectious Diseases, School of Systems Biology , George Mason University , Manassas , Virginia 20110 , United States
| | - Shun-Ping Wang
- Department of Orthopaedics , Taichung Veterans General Hospital , Taichung 407 , Taiwan
| | - Der-Yuan Chen
- Division of Immunology and Rheumatology, Department of Internal Medicine , China Medical University Hospital , Taichung 404 , Taiwan
| | - Sen-Wei Tsai
- Department of Physical Medicine and Rehabilitation, Taichung Tzu Chi Hospital , Buddhist Tzu Chi Medical Foundation , Taichung 427 , Taiwan
- Department of Physical Medicine and Rehabilitation, School of Medicine , Tzu Chi University , Hualien 970 , Taiwan
| | - Chi-Chien Lin
- Institute of Biomedical Science , National Chung-Hsing University , Taichung 402 , Taiwan
- Department of Medical Research , China Medical University Hospital , Taichung 404 , Taiwan
- Department of Medical Research and Education , Taichung Veterans General Hospital , Taichung 407 , Taiwan
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Lin SC, Chen MC, Liu S, Callahan VM, Bracci NR, Lehman CW, Dahal B, de la Fuente CL, Lin CC, Wang TT, Kehn-Hall K. Phloretin inhibits Zika virus infection by interfering with cellular glucose utilisation. Int J Antimicrob Agents 2019; 54:80-84. [PMID: 30930299 DOI: 10.1016/j.ijantimicag.2019.03.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 03/13/2019] [Accepted: 03/16/2019] [Indexed: 10/27/2022]
Abstract
Zika virus (ZIKV) is a re-emerging Flavivirus that has been linked to microcephaly and other neurological pathologies. In this study, phloretin, a glucose transporter inhibitor naturally derived from plants, was used to investigate the glucose dependence of ZIKV replication in host cells. The results showed that phloretin significantly decreased infectious titres of two ZIKV strains, namely MR766 (African genotype) and PRVABC59 (Puerto Rico genotype). The 50% effective concentration (EC50) of phloretin against MR766 and PRVABC59 was 22.85 µM and 9.31 µM, respectively. Further analyses demonstrated that decreased viral production was due to host-targeted inhibition, including decreased apoptotic caspase-3 and -7 activities and reduced phosphorylation of Akt/mTOR pathways. In addition, upon disruption of cellular glucose availability within host cells using 2-deoxy-d-glucose, ZIKV propagation was inhibited. Collectively, we demonstrate phloretin inhibition of ZIKV propagation and provide evidence of glucose utilization pathways as being important for ZIKV propagation. The activity of phloretin and its role in inhibiting glucose uptake could provide a useful foundation for the development of ZIKV antivirals.
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Affiliation(s)
- Shih-Chao Lin
- National Center for Biodefense and Infectious Diseases, George Mason University, 10650 Pyramid Place, Manassas, VA 20110, USA
| | - Mei-Chun Chen
- Center of Infectious Diseases, SRI International, 140 Research Drive, Harrisonburg, VA 22802, USA
| | - Shufeng Liu
- Center of Infectious Diseases, SRI International, 140 Research Drive, Harrisonburg, VA 22802, USA
| | - Victoria M Callahan
- National Center for Biodefense and Infectious Diseases, George Mason University, 10650 Pyramid Place, Manassas, VA 20110, USA
| | - Nicole R Bracci
- National Center for Biodefense and Infectious Diseases, George Mason University, 10650 Pyramid Place, Manassas, VA 20110, USA
| | - Caitlin W Lehman
- National Center for Biodefense and Infectious Diseases, George Mason University, 10650 Pyramid Place, Manassas, VA 20110, USA
| | - Bibha Dahal
- National Center for Biodefense and Infectious Diseases, George Mason University, 10650 Pyramid Place, Manassas, VA 20110, USA
| | - Cynthia L de la Fuente
- National Center for Biodefense and Infectious Diseases, George Mason University, 10650 Pyramid Place, Manassas, VA 20110, USA
| | - Chi-Chen Lin
- Department of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Tony T Wang
- Laboratory of Vector-Borne Viral Diseases, Division of Viral Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20903, USA.
| | - Kylene Kehn-Hall
- National Center for Biodefense and Infectious Diseases, George Mason University, 10650 Pyramid Place, Manassas, VA 20110, USA.
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9
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Tsai HC, Lehman CW, Lin CC, Tsai SW, Chen CM. Functional evaluation for adequacy of MDCK-lineage cells in influenza research. BMC Res Notes 2019; 12:101. [PMID: 30808400 PMCID: PMC6390338 DOI: 10.1186/s13104-019-4134-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 02/15/2019] [Indexed: 11/23/2022] Open
Abstract
Objective Influenza is an acute respiratory disease caused by the influenza virus which circulates annually in populations of different species. Madin-Darby Canine Kidney (MDCK) is the most widely utilized cell-line for conducting influenza research. However, the infectivity of various influenza strains in MDCK cells is not equivalent and the productivity of viral propagation is also limited. Results We tested the functional adequacy of two MDCK-lineage cell lines, conventional MDCK and MDCK/London, were evaluated by assessing their infectivity of different influenza viral strains with focus forming assays and the cellular toxicity caused by influenza infections by lactate dehydrogenase assay. Moreover, the sensitivity of cells in the presence of the antiviral agent ribavirin was assessed by MTT assay. Our results showed that MDCK/London cells efficiently propagate virus across all influenza viruses tested, are comparable to the utility of Mv1Lu cells, and are superior to conventional MDCK cells in replicating virus as indicated by an increase in virus of three to four logs, particularly in H3N2 infection. Also, the MDCK/London cells were more sensitive to the presence of antiviral drug than conventional MDCK cells. In conclusion, MDCK/London cell line could be a better platform for influenza studies and vaccine development.
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Affiliation(s)
- Hsin-Chung Tsai
- Department of Surgery, Taichung Hospital, Ministry of Health and Welfare, 199 San Min Rd., Sec. 1, Taichung, Taiwan. .,Department of Life Sciences, The iEGG and Animal Biotechnology Center, National Chung Hsing University, 145 Xinda Rd., Taichung, 402, Taiwan.
| | - Caitlin W Lehman
- School of System Biology, George Mason University, Manassas, VA, USA
| | - Chi-Chieh Lin
- Department of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Sen-Wei Tsai
- Department of Physical Medicine and Rehabilitation, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan
| | - Chuan-Mu Chen
- Department of Life Sciences, The iEGG and Animal Biotechnology Center, National Chung Hsing University, 145 Xinda Rd., Taichung, 402, Taiwan.
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10
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Wu PC, Chuo WH, Lin SC, Lehman CW, Lien CZ, Wu CS, Lin CC. Sclareol attenuates the development of atopic dermatitis induced by 2,4-dinitrochlorobenzene in mice. Immunopharmacol Immunotoxicol 2019; 41:109-116. [PMID: 30704333 DOI: 10.1080/08923973.2018.1555846] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Context: Atopic dermatitis is a common chronic inflammatory skin disease affecting up to 20% of children and 1% of adults worldwide. Treatment of atopic dermatitis include corticosteroids and immunosuppressants, such as calcineurin inhibitors and methotrexate. However, these treatments often bring about adverse effects including skin atrophy, osteoporosis, skin cancer, and metabolic syndrome. Objective: In this study, we evaluated the therapeutic effects and mechanisms of sclareol, a natural diterpene, on atopic dermatitis (AD)-like skin lesions induced by 2,4-dinitrochlorobenzene (DNCB) in mice. Materials and methods: To evaluate the effect of sclareol in vivo model, BALB/c mice were repeatedly injected intraperitoneally with sclareol (50 and 100 mg/kg) in 2,4-dinitrochlorobenzene (DNCB)-induced AD-like murine model. Major assays were enzyme-linked immunosorbent assay, histological analysis, flow cytometry, western blot analysis. Results: Intraperitoneal administration of sclareol (50 and 100 mg/kg) significantly attenuated AD-like symptoms, such as serum IgE levels, epidermal/dermal hyperplasia, and the numbers of infiltrated mast cells. In addition, systemic sclareol treatments reduced local pro-inflammatory cytokine concentrations, including IL-6, IL-1b, TNF-a, IL-4, IFN-g, and IL-17A, on AD-like lesions. Furthermore, we demonstrated that sclareol also suppressed T cell activation and the capability of cytokine productions (IFN-g, IL-4 and IL-17A) in response to DNCB stimulation. By examining the skin homogenate, we found that sclareol inhibited the AD-like severity likely through suppressions of both NF-kB translocation and phosphorylation of the MAP kinase pathway. Discussion and conclusions: Cumulatively, our results indicate that sclareol induced anti-inflammatory effects against the atopic dermatitis elicited by DNCB. Thus, sclareol is worth of being further evaluated for its potential therapeutic benefits for the clinical treatment of AD.
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Affiliation(s)
- Po-Chang Wu
- a Rheumatology and Immunology Center, China Medical University Hospital , Taichung , Taiwan
| | - Wen-Ho Chuo
- b Department of Pharmacy , Tajen University , Pingtung , Taiwan
| | - Shih-Chao Lin
- c School of Systems Biology , National Center for Biodefense and Infectious Diseases , George Mason University , Manassas , VA , USA
| | - Caitlin W Lehman
- c School of Systems Biology , National Center for Biodefense and Infectious Diseases , George Mason University , Manassas , VA , USA
| | - Christopher Z Lien
- d Biodefense Program, Schar School of Policy and Government , George Mason University , Fairfax , VA , USA
| | - Chieh-Shan Wu
- e Department of Dermatology , Kaohsiung Veterans General Hospital , Kaohsiung , Taiwan
| | - Chi-Chien Lin
- f Department of Medical Research , China Medical University Hospital , Taichung , Taiwan.,g Institute of Biomedical Science and Rong Hsing Research Center for Translational Medicine, National Chung-Hsing University , Taichung , Taiwan , ROC
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11
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Lehman CW. Natural rubber latex allergy, an epidemic in the health field. HAWAII MEDICAL JOURNAL 1999; 58:152-5. [PMID: 10416309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
The object of this paper is to educate health care providers of the markedly increased incidence of natural rubber latex (NRL) allergy to epidemic proportions during the past 10 to 12 years. A review of latex allergy problems in health care providers as well as patients is presented. Also reported is a questionnaire survey of institutions listed with the Health Care Association of Hawaii.
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12
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Abstract
Eukaryotic viruses can maintain latency in dividing cells as extrachromosomal nuclear plasmids. Segregation and nuclear retention of DNA is, therefore, a key issue in retaining copy number. The E2 enhancer protein of the papillomaviruses is required for viral DNA replication and transcription. Viral mutants that prevent phosphorylation of the bovine papillomavirus type 1 (BPV) E2 protein are transformation-defective, despite normal viral gene expression and replication function. Cell colonies harboring such mutants show sectoring of viral DNA and are unable to maintain the episome. We find that transforming viral DNA attaches to mitotic chromosomes, in contrast to the mutant genome encoding the E2 phosphorylation mutant. Second-site suppressor mutations were uncovered in both E1 and E2 genes that allow for transformation, maintenance, and chromosomal attachment. E2 protein was also found to colocalize to mitotic chromosomes, whereas the mutant did not, suggesting a direct role for E2 in viral attachment to chromosomes. Such viral hitch-hiking onto cellular chromosomes is likely to provide a general mechanism for maintaining nuclear plasmids.
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Affiliation(s)
- C W Lehman
- Molecular and Cell Biology Department, University of California, Berkeley, CA 94720, USA
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Lim DA, Gossen M, Lehman CW, Botchan MR. Competition for DNA binding sites between the short and long forms of E2 dimers underlies repression in bovine papillomavirus type 1 DNA replication control. J Virol 1998; 72:1931-40. [PMID: 9499046 PMCID: PMC109485 DOI: 10.1128/jvi.72.3.1931-1940.1998] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [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: 02/06/2023] Open
Abstract
Papillomaviruses establish a long-term latency in vivo by maintaining their genomes as nuclear plasmids in proliferating cells. Bovine papillomavirus type 1 encodes two proteins required for viral DNA replication: the helicase E1 and the positive regulator E2. The homodimeric E2 is known to cooperatively bind to DNA with E1 to form a preinitiation complex at the origin of DNA replication. The virus also codes for two short forms of E2 that can repress viral functions when overexpressed, and at least one copy of the repressor is required for stable plasmid maintenance in transformed cells. Employing a tetracycline-regulated system to control E1 and E2 production from integrated loci, we show that the short form of E2 negatively regulates DNA replication. We also found that the short form could repress replication in a cell-free replication system and that the repression requires the DNA binding domain of the protein. In contrast, heterodimers of the short and long forms were activators and, by footprint analysis, were shown to be as potent as homodimeric E2 in loading E1 to its cognate site. DNA binding studies show that when E1 levels are low and are dependent upon E2 for occupancy of the origin site, the repressor can block E1-DNA interactions. We conclude that DNA replication modulation results from competition between the different forms of E2 for DNA binding. Given that heterodimers are active and that the repressor form of E2 shows little cooperativity with E1 for DNA binding, this protein is a weak repressor.
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Affiliation(s)
- D A Lim
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3204, USA
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14
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Lehman CW, King DS, Botchan MR. A papillomavirus E2 phosphorylation mutant exhibits normal transient replication and transcription but is defective in transformation and plasmid retention. J Virol 1997; 71:3652-65. [PMID: 9094639 PMCID: PMC191514 DOI: 10.1128/jvi.71.5.3652-3665.1997] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [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: 02/04/2023] Open
Abstract
Papillomavirus DNA persists in infected cells as a nuclear plasmid, causing epithelial lesions in many hosts, including humans. The viral protein E2 is required for both replication and transcription to facilitate this persistence. Bovine papillomavirus E2 protein is phosphorylated at two predominant sites. Phosphorylation of one of these sites (serine 301) inhibits replication of the genome. Using mass spectrometry and Edman sequencing, we have mapped additional phosphorylation sites in tryptic peptides to positions which lie primarily in the putatively unstructured hinge region of E2. Mutation of the major sites facilitates transformation in the absence of viral repressors and only has a minor effect on transformation when the repressors are present. Mutation of the major phosphorylation sites combined with one additional change at a newly discovered site (serine 235) blocks transformation. Transformation can be restored by mutating this residue to aspartic acid, mimicking a phosphorylated amino acid, suggesting that phosphorylation is key to the regulation. Transformation by the mutant genome can also be rescued by ectopic expression of the E2 enhancer protein, demonstrating a loss of function by the mutant protein and not a toxic defect. In transient assays, phosphorylation site mutants of E2 protein were normal for all viral functions tested, including replication, transcriptional activation and repression (by the overlapping mutant repressors), protein accumulation, and surprisingly, viral oncogene E5 promoter activation. While the mutant genome transiently replicated to high levels, stable replication was defective, suggesting that a function of E2 required for plasmid retention is regulated by phosphorylation.
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Affiliation(s)
- C W Lehman
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3204, USA.
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15
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Carroll D, Lehman CW, Jeong-Yu S, Dohrmann P, Dawson RJ, Trautman JK. Distribution of exchanges upon homologous recombination of exogenous DNA in Xenopus laevis oocytes. Genetics 1994; 138:445-57. [PMID: 7828826 PMCID: PMC1206161 DOI: 10.1093/genetics/138.2.445] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [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: 01/27/2023] Open
Abstract
Homologous recombination between DNA molecules injected into Xenopus oocyte nuclei was investigated by examining the recovery of information from differentially marked parental sequences. The injected recombination substrate was a linear DNA with terminal direct repeats of 1246 bp; one repeat differed from the other by eight single base-pair substitutions, distributed throughout the region of homology, each of which created or destroyed a restriction enzyme site. Recombination products were recovered and analyzed for their content of the diagnostic sites, either directly by Southern blot-hybridization or after cloning in bacteria. The majority (76%) of the cloned products appeared to be the result of simple exchanges-i.e., there was one sharp transition from sequences derived from one parent to sequences derived from the other. These simple exchanges were concentrated near the ends of the homologous interval and, thus, near the sites of the original molecular ends. Placing marked sites on only one side of the homologous overlap showed that marker recovery was governed largely by the positions of the molecular ends and not by the markers themselves. When a terminal nonhomology was present at one end of the substrate, the yield of recombinants was sharply decreased, but the pattern of exchanges was not affected, suggesting that products from end-blocked substrates arise by the same recombination pathway. Because of considerable evidence supporting a nonconservative, resection-annealing mechanism for recombination in oocytes, we interpret the distribution of exchanges as resulting from long-patch repair of extensive heteroduplex intermediates.
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Affiliation(s)
- D Carroll
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City 84132
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16
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Abstract
We have hypothesized that the inheritance of heteroallelic markers during recombination of homologous DNAs in Xenopus oocytes is determined by resolution of a heteroduplex intermediate containing multiple single-base mismatches. To test this idea, we prepared synthetic heteroduplexes carrying 8 separate mispairs in vitro and injected them into oocyte nuclei. DNA was recovered and analyzed directly, by Southern blot-hybridization, and indirectly, by cloning individual repair products in bacteria. Mismatch correction was quite efficient in the oocytes; markers on the same strand were commonly co-corrected, indicating a long-patch mechanism; and the distribution of markers was very similar to that obtained by recombination. This supports our interpretation of the recombination outcome in terms of a resection-annealing mechanism. The injected heteroduplexes carried strand breaks (nicks) as a result of their method of preparation. We tested the idea that mismatch correction might be nick-directed by ligating the strands of the heteroduplex substrate to form covalently closed circles. Repair in oocytes was still efficient, and long patches predominated; but the pattern of recovered markers was quite different than with the nicked substrate. This suggests that nicks, when present, do indeed direct repair, but that, in their absence, recognition of specific mismatches governs repair of the ligated heteroduplexes.
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Affiliation(s)
- C W Lehman
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City 84132
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17
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Abstract
When linear DNAs are injected into Xenopus laevis eggs, they are converted into several different kinds of recombination products. Some molecules undergo homologous recombination by a resection-annealing mechanism; some ends are precisely ligated; and some ends are joined by illegitimate means. The homologous and illegitimate products are also generated in nuclear extracts from stage VI Xenopus oocytes. In order to gain insight into the mechanism(s) of illegitimate end joining, we amplified, cloned and sequenced a number of junctions from eggs and from oocyte extracts. The egg junctions fell into three categories: some with no homology at the join point that may have been produced by blunt-end ligation; some based on small, but significant homologies (5-10 bp); and some with matches of only 1 or 2 nucleotides at the joint. Junctions made in oocyte extracts were largely of the latter type. In the extracts, formation of illegitimate joints required the addition of all four deoxyribonucleoside triphosphates and was inhibited by aphidicolin. This indicates that this process involves DNA synthesis, and mechanisms incorporating this feature are considered. The spectrum of recombination products formed in Xenopus eggs is very reminiscent of those produced from DNA introduced into mammalian cells.
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Affiliation(s)
- C W Lehman
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City 84132
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18
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Abstract
Exogenous DNA is efficiently recombined when injected into the nuclei of Xenopus laevis oocytes. This reaction proceeds by a homologous resection-annealing mechanism which depends on the activity of a 5'-->3' exonuclease. Two possible functions for this recombination activity have been proposed: it may be a remnant of an early process in oogenesis, such as meiotic recombination or amplification of genes coding for rRNA, or it may reflect materials stored for embryogenesis. To test these hypotheses, recombination capabilities were examined with oocytes at various developmental stages. Late-stage oocytes performed only homologous recombination, whereas the smallest oocytes ligated the restriction ends of the injected DNA but supported no homologous recombination. This transition from ligation to recombination activity was also seen in nuclear extracts from these same stages. Exonuclease activity was measured in the nuclear extracts and found to be low in early stages and then to increase in parallel with recombination capacity in later stages. The accumulation of exonuclease and recombination activities during oogenesis suggests that they are stored for embryogenesis and are not present for oocyte-specific functions. Eggs were also tested and found to catalyze homologous recombination, ligation, and illegitimate recombination. Retention of homologous recombination in eggs is consistent with an embryonic function for the resection-annealing mechanism. The observation of all three reactions in eggs suggests that multiple pathways are available for the repair of double-strand breaks during the extremely rapid cleavage stages after fertilization.
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Affiliation(s)
- C W Lehman
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City 84132
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19
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Abstract
A procedure is described that facilitates the isolation of large quantities of nuclei (germinal vesicles or GVs) from late stage Xenopus laevis oocytes. The method was developed by modifying techniques described in two published reports (F. Scalenghe et al. (1978) Chromosoma 66, 299-308; I. Ruberti et al. (1989) Anal. Biochem. 180, 177-180). Methods were chosen which optimize yields of GVs and homologous recombination activity. This procedure yields up to 90% of the total GVs present in 70 ml of oocytes. Proteins in the extract made from these GVs are predominantly of nuclear origin; little cytoplasmic contamination is detected as measured by alpha-tubulin content. The extract catalyzes the complete recombination of linear, terminally homologous DNA, as observed in injected oocytes. The extract also performs other nuclear processes including transcription, repair-type DNA synthesis, chromatin assembly, NDP kinase reactions, and dsRNA deamination. Because this procedure greatly increases the yield of GVs over manual isolation protocols, and the resulting extract is capable of carrying out a variety of typical nuclear processes, it should expedite the purification of components found in oocyte GVs, including proteins required for homologous recombination.
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Affiliation(s)
- C W Lehman
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City 84132
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20
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Abstract
Xenopus laevis oocytes efficiently recombine linear DNA injected into their nuclei (germinal vesicles). This process requires homologous sequences at or near the molecular ends. Here we report that a cell-free extract made from germinal vesicles is capable of accomplishing the complete recombination reaction in vitro. Like the in vivo process, the extract converts the overlapping ends of linear substrate molecules into covalently closed products. Establishment of this cell-free system has allowed examination of the cofactors required for recombination. The first step involves a 5'----3' exonuclease activity that requires a divalent cation but not NTPs. Completion of recombination requires a hydrolyzable NTP; maximal product formation occurs in the presence of millimolar levels of ATP or dATP. At submillimolar levels of all four dNTPs, homologous recombination is inefficient, and a side reaction produces end-joined products. This cell-free system should facilitate a step-by-step understanding of an homologous recombination pathway that operates not only in Xenopus laevis oocytes but also in cells from a wide variety of organisms.
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Affiliation(s)
- C W Lehman
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City 84132
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21
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Affiliation(s)
- D Carroll
- Department of Biochemistry, University of Utah Medical School, Salt Lake City 84132
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22
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Lehman CW. The leukocytic food allergy test: a study of its reliability and reproducibility. Effect of diet and sublingual food drops on this test. Ann Allergy 1980; 45:150-8. [PMID: 6998331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The reproducibility of the cytotoxic food test was studied with aliquots of the same blood sample done in duplicate, as well as repeatedly retesting the same patient. The effect on the test of ingestion of foods and of sublingual food drops was studied. The cytotoxic food test is found unreliable as a diagnostic test. It fluctuates considerably from day to day and from week to week without relation to the foods ingested or to the administration of sublingual food drops. The cytotoxic food test and sublingual provocative food test are both unreliable for diagnosis of food allergy.
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Lehman CW. A double-blind study of sublingual provocative food testing: a study of its efficacy. Ann Allergy 1980; 45:144-9. [PMID: 7416559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Fifteen patients with chronic allergic conditions were tested in a double-blind manner, using sublingual food drops containing egg, corn, milk, yeast or placebo. Edema and swelling of the nasal mucosa were observed as frequently when a placebo was given as when sublingual food drops were given. This method of testing does not differentiate between placebo and food drops.
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Lehman CW. Control of chronic erythema nodosum with naproxen. Cutis 1980; 26:66-7. [PMID: 7389399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A patient with chronic erythema nodosum of two years' duration, who did not respond to treatment with aspirin or with phenylbutazone therapy, had a dramatic response and improvement when treated with naproxen.
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Lehman CW. Sugar cane smoke, an allergenic agent. Hawaii Med J 1976; 35:336-9. [PMID: 1002460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Lehman CW. Firecracker smoke is not an allergen. Hawaii Med J 1976; 35:165-6. [PMID: 947863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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