1
|
Chen CC, Chen YY, Yeh CC, Hsu CW, Yu SJ, Hsu CH, Wei TC, Ho SN, Tsai PC, Song YD, Yen HJ, Chen XA, Young JJ, Chuang CC, Dou HY. Alginate-Capped Silver Nanoparticles as a Potent Anti-mycobacterial Agent Against Mycobacterium tuberculosis. Front Pharmacol 2021; 12:746496. [PMID: 34899300 PMCID: PMC8660078 DOI: 10.3389/fphar.2021.746496] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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] [Received: 07/23/2021] [Accepted: 10/27/2021] [Indexed: 11/13/2022] Open
Abstract
Tuberculosis (TB) is a leading cause of death from a single infectious agent, Mycobacterium tuberculosis (Mtb). Although progress has been made in TB control, still about 10 million people worldwide develop TB annually and 1.5 million die of the disease. The rapid emergence of aggressive, drug-resistant strains and latent infections have caused TB to remain a global health challenge. TB treatments are lengthy and their side effects lead to poor patient compliance, which in turn has contributed to the drug resistance and exacerbated the TB epidemic. The relatively low output of newly approved antibiotics has spurred research interest toward alternative antibacterial molecules such as silver nanoparticles (AgNPs). In the present study, we use the natural biopolymer alginate to serve as a stabilizer and/or reductant to green synthesize AgNPs, which improves their biocompatibility and avoids the use of toxic chemicals. The average size of the alginate-capped AgNPs (ALG-AgNPs) was characterized as nanoscale, and the particles were round in shape. Drug susceptibility tests showed that these ALG-AgNPs are effective against both drug-resistant Mtb strains and dormant Mtb. A bacterial cell-wall permeability assay showed that the anti-mycobacterial action of ALG-AgNPs is mediated through an increase in cell-wall permeability. Notably, the anti-mycobacterial potential of ALG-AgNPs was effective in both zebrafish and mouse TB animal models in vivo. These results suggest that ALG-AgNPs could provide a new therapeutic option to overcome the difficulties of current TB treatments.
Collapse
Affiliation(s)
- Cheng-Cheung Chen
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan.,Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - Yih-Yuan Chen
- Department of Biochemical Science and Technology, National Chiayi University, Chia-Yi, Taiwan
| | - Chang-Ching Yeh
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Chia-Wei Hsu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Shang-Jie Yu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Chih-Hao Hsu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Ting-Chun Wei
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Sin-Ni Ho
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Pei-Chu Tsai
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Yung-Deng Song
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Hui-Ju Yen
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan.,School of Pharmacy, National Defense Medical Center, Taipei, Taiwan
| | - Xin-An Chen
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Jenn-Jong Young
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Chuan-Chung Chuang
- School of Dentistry and Graduate Institute of Dental Science, National Defense Medical Center, Taipei, Taiwan.,Department of Dentistry, Tri-Service General Hospital, Taipei, Taiwan
| | - Horng-Yunn Dou
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan.,Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| |
Collapse
|
2
|
Yang SJ, Wei TC, Hsu CH, Ho SN, Lai CY, Huang SF, Chen YY, Liu SJ, Yu GY, Dou HY. Characterization of Virus Replication, Pathogenesis, and Cytokine Responses in Syrian Hamsters Inoculated with SARS-CoV-2. J Inflamm Res 2021; 14:3781-3795. [PMID: 34408462 PMCID: PMC8366787 DOI: 10.2147/jir.s323026] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/01/2021] [Indexed: 01/08/2023] Open
Abstract
Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus which caused a global respiratory disease pandemic beginning in December 2019. Understanding the pathogenesis of infection and the immune responses in a SARS-CoV-2-infected animal model is urgently needed for vaccine development. Methods Syrian hamsters (Mesocricetus auratus) were intranasally inoculated with 105, 5×105, and 106 TCID50 of SARS-CoV-2 per animal and studied for up to 14 days. Body weight, viral load and real-time PCR amplification of the SARS-CoV-2 N gene were measured. On days 3, 6 and 9, lung, blood, liver, pancreas, heart, kidney, and bone marrow were harvested and processed for pathology, viral load, and cytokine expression. Results Body weight loss, increased viral load, immune cell infiltration, upregulated cytokine expression, viral RNA, SARS-CoV-2 nucleoprotein, and mucus were detected in the lungs, particularly on day 3 post-infection. Extremely high expression of the pro-inflammatory cytokines MIP-1 and RANTES was detected in lung tissue, as was high expression of IL-1β, IL-6, IL-12, and PD-L1. The glutamic oxalacetic transaminase/glutamic pyruvic transaminase (GOT/GPT) ratio in blood was significantly increased at 6 days post-infection, and plasma amylase and lipase levels were also elevated in infected hamsters. Conclusion Our results provide new information on immunological cytokines and biological parameters related to the pathogenesis and immune response profile in the Syrian hamster model of SARS-CoV-2 infection.
Collapse
Affiliation(s)
- Shiu-Ju Yang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan
| | - Ting-Chun Wei
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan
| | - Chih-Hao Hsu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan
| | - Sin-Ni Ho
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan
| | - Chi-Yun Lai
- Pathology Core Laboratory, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan
| | - Shiu-Feng Huang
- Pathology Core Laboratory, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan.,National Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan
| | - Yih-Yuan Chen
- Department of Biochemical Science and Technology, National Chiayi University, Chia-Yi, 60070, Taiwan
| | - Shih-Jen Liu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan
| | - Guann-Yi Yu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan
| | - Horng-Yunn Dou
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, 35053, Taiwan.,Department of Biological Science & Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| |
Collapse
|
3
|
Soria JC, Ho SN, Varella-Garcia M, Iafrate AJ, Solomon BJ, Shaw AT, Blackhall F, Mok TS, Wu YL, Pestova K, Wilner KD, Polli A, Paolini J, Lanzalone S, Green S, Camidge DR. Correlation of extent of ALK FISH positivity and crizotinib efficacy in three prospective studies of ALK-positive patients with non-small-cell lung cancer. Ann Oncol 2019; 29:1964-1971. [PMID: 30010763 DOI: 10.1093/annonc/mdy242] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background In clinical trials of patients with anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC) treated with crizotinib, evaluation of the relationship between the percentage of ALK-positive cells by fluorescence in situ hybridization (FISH)-particularly near the cut-off defining positive status-and clinical outcomes have been limited by small sample sizes. Patients and methods Data were pooled from three large prospective trials (one single-arm and two randomized versus chemotherapy) of crizotinib in patients with ALK-positive NSCLC determined by Vysis ALK Break Apart FISH using a cut-off of ≥15% ALK-positive cells. Logistic regression and proportional hazards regression analyses were used to explore the association of percent ALK-positive cells with objective response and progression-free survival (PFS), respectively. Results Of 11 081 screened patients, 1958 (18%) were ALK positive, 7512 (68%) were ALK negative, and 1540 (14%) were uninformative. Median percentage of ALK-positive cells was 58% in ALK-positive patients and 2% in ALK-negative patients. Of ALK-positive patients, 5% had 15%-19% ALK-positive cells; of ALK-negative patients, 2% had 10%-14% ALK-positive cells. Objective response rate for ALK-positive, crizotinib-treated patients with ≥20% ALK-positive cells was 56% (n = 700/1246), 55% (n = 725/1312) for those with ≥15% ALK-positive cells, and 38% for those with 15%-19% ALK-positive cells (n = 25/66). As a continuous variable, higher percentages of ALK-positive cells were estimated to be associated with larger differences in objective response and PFS between crizotinib and chemotherapy; however, tests for interaction between treatment and percentage of ALK-positive cells were not significant (objective response, P = 0.054; PFS, P = 0.17). Conclusions Patients with ALK-positive NSCLC benefit from treatment with crizotinib across the full range of percentage of ALK-positive cells, supporting the clinical utility of the 15% cut-off. The small number of patients with scores near the cut-off warrant additional study given the potential for misclassification of ALK status due to technical or biologic reasons.
Collapse
Affiliation(s)
- J-C Soria
- Department of Medical Oncology, Gustave Roussy Cancer Campus, Villejuif; Université Paris-Sud, Orsay, France.
| | - S N Ho
- Global Product Development, Pfizer Oncology, La Jolla
| | - M Varella-Garcia
- Division of Medical Oncology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora
| | - A J Iafrate
- Massachusetts General Hospital Cancer Center, Massachusetts General Hospital, Boston, USA
| | - B J Solomon
- Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - A T Shaw
- Massachusetts General Hospital Cancer Center, Massachusetts General Hospital, Boston, USA
| | - F Blackhall
- The Christie Hospital and Institute of Cancer Sciences, Manchester University, Manchester, UK
| | - T S Mok
- Department of Clinical Oncology, The Chinese University of Hong Kong, Hong Kong
| | - Y-L Wu
- Guangdong General Hospital, Guangdong Lung Cancer Institute, Guangzhou, China
| | | | - K D Wilner
- Global Product Development, Pfizer Oncology, La Jolla
| | - A Polli
- Global Clinical Development and Operations, Pfizer Oncology, Milan, Italy
| | - J Paolini
- Global Clinical Development and Operations, Pfizer Oncology, Milan, Italy
| | - S Lanzalone
- Global Clinical Development and Operations, Pfizer Oncology, Milan, Italy
| | - S Green
- Global Product Development, Pfizer Oncology, Groton, USA
| | - D R Camidge
- Division of Medical Oncology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora
| |
Collapse
|
4
|
Trama J, Lu Q, Hawley RG, Ho SN. The NFAT-related protein NFATL1 (TonEBP/NFAT5) is induced upon T cell activation in a calcineurin-dependent manner. J Immunol 2000; 165:4884-94. [PMID: 11046013 DOI: 10.4049/jimmunol.165.9.4884] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
NFAT DNA binding complexes regulate programs of cellular activation and differentiation by translating receptor-dependent signaling events into specific transcriptional responses. NFAT proteins, originally defined as calcium/calcineurin-dependent regulators of cytokine gene transcription in T lymphocytes, are expressed in many different cell types and represent critical signaling intermediates that mediate an increasingly wide spectrum of biologic responses. Recent studies have identified a novel protein containing a region of similarity to the NFAT DNA binding domain. Here we demonstrate that this protein, designated NFATL1 (also known as tonicity enhancer binding protein and NFAT5) is expressed at high levels in the thymus but is undetectable in mature lymphocytes. However, NFATL1 can be induced in both primary quiescent T lymphocytes and differentiated Th1 and Th2 cell populations upon mitogen- or Ag receptor-dependent activation. The induction of NFATL1 protein, as well as NFATL1-dependent transcription, is inhibited by cyclosporin A and FK506, and expression of constitutively active calcineurin induces NFATL1-dependent transcription. Overexpression of NFATc1 and inhibition of NFATc activity through the use of a dominant negative NFATc1 protein have no affect on NFATL1-dependent transcription, indicating that NFATc proteins do not play a role in the calcineurin-dependent induction of NFATL1. Interestingly, induction of NFATL1 by a hyperosmotic stimulus is not blocked by the inhibition of calcineurin. Moreover, osmotic stress response genes such as aldose reductase are not induced upon T cell activation. Thus inducible expression of NFATL1 represents a mechanism by which receptor-dependent signals as well as osmotic stress signals are translated into transcriptional responses that regulate cell function.
Collapse
Affiliation(s)
- J Trama
- Department of Pathology, University of California at San Diego, La Jolla, CA 92093, USA
| | | | | | | |
Collapse
|
5
|
Timmerman LA, Healy JI, Ho SN, Chen L, Goodnow CC, Crabtree GR. Redundant expression but selective utilization of nuclear factor of activated T cells family members. The Journal of Immunology 1997. [DOI: 10.4049/jimmunol.159.6.2735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Nuclear factor of activated T cells (NF-AT) complexes regulate the induction of many early T cell activation molecules. Four related proteins can function as the cytoplasmic subunit of NF-AT, and their overlapping expression patterns and the mild phenotype of the NF-ATp null mice suggest that they may be functionally redundant. We characterized the distribution and activation of cytoplasmic NF-AT proteins in mature lymphocytes and found that NF-ATc, NF-ATp, and NF-AT4/x/c3 are co-expressed and co-regulated in mature T and B cells. Each protein forms independent DNA binding complexes, and at physiologic concentrations, NF-ATc and NF-ATp complexes out-compete NF-AT4/x/c3 for occupancy of NF-AT sites from the IL-2, IL-3/granulocyte-macrophage CSF, IL-4, and CD40 ligand genes. This predicts heavily redundant immune regulatory functions of NF-ATp and NF-ATc, but distinct activities for NF-AT4/x/c3. Additionally, Ab interaction with NF-ATp induces high affinity NF-kappaB site interaction, suggesting that nuclear partners may dramatically vary the specificity of the NF-AT family.
Collapse
Affiliation(s)
- L A Timmerman
- The Howard Hughes Medical Institute, Stanford University, CA 94305, USA
| | - J I Healy
- The Howard Hughes Medical Institute, Stanford University, CA 94305, USA
| | - S N Ho
- The Howard Hughes Medical Institute, Stanford University, CA 94305, USA
| | - L Chen
- The Howard Hughes Medical Institute, Stanford University, CA 94305, USA
| | - C C Goodnow
- The Howard Hughes Medical Institute, Stanford University, CA 94305, USA
| | - G R Crabtree
- The Howard Hughes Medical Institute, Stanford University, CA 94305, USA
| |
Collapse
|
6
|
Timmerman LA, Healy JI, Ho SN, Chen L, Goodnow CC, Crabtree GR. Redundant expression but selective utilization of nuclear factor of activated T cells family members. J Immunol 1997; 159:2735-40. [PMID: 9300694] [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] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Nuclear factor of activated T cells (NF-AT) complexes regulate the induction of many early T cell activation molecules. Four related proteins can function as the cytoplasmic subunit of NF-AT, and their overlapping expression patterns and the mild phenotype of the NF-ATp null mice suggest that they may be functionally redundant. We characterized the distribution and activation of cytoplasmic NF-AT proteins in mature lymphocytes and found that NF-ATc, NF-ATp, and NF-AT4/x/c3 are co-expressed and co-regulated in mature T and B cells. Each protein forms independent DNA binding complexes, and at physiologic concentrations, NF-ATc and NF-ATp complexes out-compete NF-AT4/x/c3 for occupancy of NF-AT sites from the IL-2, IL-3/granulocyte-macrophage CSF, IL-4, and CD40 ligand genes. This predicts heavily redundant immune regulatory functions of NF-ATp and NF-ATc, but distinct activities for NF-AT4/x/c3. Additionally, Ab interaction with NF-ATp induces high affinity NF-kappaB site interaction, suggesting that nuclear partners may dramatically vary the specificity of the NF-AT family.
Collapse
Affiliation(s)
- L A Timmerman
- The Howard Hughes Medical Institute, Stanford University, CA 94305, USA
| | | | | | | | | | | |
Collapse
|
7
|
Abstract
The skin is an attractive tissue for regulated target gene expression by virtue of its accessibility to topical regulating stimuli. We have used synthetic ligand-driven intracellular oligomerization to accomplish specific target gene regulation in human skin keratinocytes and fibroblasts. GAL4 DNA binding domains and VP16 transactivation domains, each linked to the FK506 binding protein, were expressed in normal human skin keratinocytes and fibroblasts. These hybrid proteins underwent heterodimerization via the novel intracellular dimerizing agent FK1012 to generate a heterodimeric activator of target gene expression in vitro. Dimeric FK1012, but not monomeric FK506M induced target gene expression in a dose-dependent fashion. FK1012 exerted no detectable nonspecific effects on expression of cutaneous genes and did not alter cellular proliferation kinetics. Controlled oligomerization of hybrid transcription activators offers a potential approach to target gene regulation in cells of normal human skin.
Collapse
Affiliation(s)
- R A Freiberg
- Dermatology Service, VA Palo Alto Health Care System, Palo Alto, California 94304, USA
| | | | | |
Collapse
|
8
|
Beals CR, Clipstone NA, Ho SN, Crabtree GR. Nuclear localization of NF-ATc by a calcineurin-dependent, cyclosporin-sensitive intramolecular interaction. Genes Dev 1997; 11:824-34. [PMID: 9106655 DOI: 10.1101/gad.11.7.824] [Citation(s) in RCA: 330] [Impact Index Per Article: 12.2] [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: 02/04/2023]
Abstract
The NF-AT family of transcription factors participates in the regulation of early immune response genes such as IL-2, IL-4, CD40 ligand, and Fas ligand in response to Ca2+/calcineurin signals initiated at the antigen receptor. Calcineurin activation leads to the rapid translocation of NF-AT family members from cytoplasm to nucleus, an event that is blocked by the immunosuppressive drugs cyclosporin A and FK506. We show that translocation requires two redundant nuclear localization sequences and that one sequence is in an intramolecular association with phosphorserines in a conserved motif located at the amino terminus of each NF-AT protein. Mutation of serines in this motif in NF-ATc both disrupts this intramolecular interaction and leads to nuclear localization, suggesting a model of NF-AT nuclear import in which dephosphorylation by calcineurin causes exposure of two nuclear localization sequences.
Collapse
Affiliation(s)
- C R Beals
- Department of Developmental Biology, Stanford University, California 94305-5428, USA
| | | | | | | |
Collapse
|
9
|
Wolfe SA, Zhou P, Dötsch V, Chen L, You A, Ho SN, Crabtree GR, Wagner G, Verdine GL. Unusual Rel-like architecture in the DNA-binding domain of the transcription factor NFATc. Nature 1997; 385:172-6. [PMID: 8990122 DOI: 10.1038/385172a0] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [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: 02/03/2023]
Abstract
Transcription factors of the NFAT family regulate the production of effector proteins that coordinate the immune response. The immunosuppressive drugs FK506 and cyclosporin A (CsA) act by blocking a Ca2+-mediated signalling pathway leading to NFAT. Although FK506 and CsA have enabled human organs to be transplanted routinely, the toxic side-effects of these drugs limit their usage. This toxicity might be absent in antagonists that target NFAT directly. As a first step in the structure-based search for NFAT antagonists, we now report the identification and solution structure of a 20K domain of NFATc (NFATc-DBD) that is both necessary and sufficient to bind DNA and activate transcription cooperatively. Although the overall fold of the NFATc DNA-binding domain is related to that of NF-kappaB p50 (refs 2, 3), the two proteins use significantly different strategies for DNA recognition. On the basis of these results, we present a model for the cooperative complex formed between NFAT and the mitogenic transcription factor AP-1 on the interleukin-2 enhancer.
Collapse
Affiliation(s)
- S A Wolfe
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Abstract
Cells need to distinguish between transient Ca2+ signals that induce events such as muscle contraction, secretion, adhesion and synaptic transmission, and sustained Ca2+ signals that are involved in cell proliferation and differentiation. The latter class of events is blocked in lymphocytes by the immunosuppressive drugs cyclosporin A and FK506, which inhibit calcineurin, a Ca2+-activated serine/threonine phosphatase necessary for the nuclear import of NF-AT transcription factors. Here we report that sustained high concentrations of Ca2+, but not transient pulses, are required to maintain NF-AT transcription factors in the nucleus, where they participate in Ca2+-dependent induction of genes required for lymphocyte activation and proliferation. Furthermore, overexpression and constitutive nuclear localization of NF-AT, but not Jun, Fos, NF-kappaB, Oct or Ets family members, renders the interleukin-2 enhancer in Jurkat T lymphocytes resistant to FK506 and cyclosporin A. Thus a primary effect of these immunosuppressive reagents is to control the subcellular localization of the NF-AT family of transcription factors.
Collapse
Affiliation(s)
- L A Timmerman
- Department of Developmental Biology, Stanford University School of Medicine, California 94305, USA
| | | | | | | | | |
Collapse
|
11
|
Abstract
Eukaryotic transcriptional activators mediate transcriptional induction through stabilization of the preinitiation complex, probably through direct interactions with basal transcription factors. In vitro studies on the role of an activator in the maintenance of on-going transcription (reinitiation) have been contradictory, suggesting that, after formation of a preinitiation complex, an activator may or may not be necessary for transcription to be maintained. We have developed a means of regulating transcription in living cells through the use of both homodimeric and heterodimerizing synthetic ligands that allow the ligand-dependent association and disassociation of a transcriptional activation domain with a promoter. Here we report that maintaining the transcription of endogenous genes in vivo, in both yeast and human cells, requires the continuous presence of the activation domain. The use of synthetic ligands as a transcriptional on-off switch represents a powerful means of controlling the transcription in vitro and in vivo for both experimental and therapeutic purposes.
Collapse
Affiliation(s)
- S N Ho
- Department of Pathology, Howard Hughes Medical Institute, Stanford University School of Medicine, California 94305, USA
| | | | | | | | | |
Collapse
|
12
|
Spencer DM, Belshaw PJ, Chen L, Ho SN, Randazzo F, Crabtree GR, Schreiber SL. Functional analysis of Fas signaling in vivo using synthetic inducers of dimerization. Curr Biol 1996; 6:839-47. [PMID: 8805308 DOI: 10.1016/s0960-9822(02)00607-3] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.3] [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: 02/02/2023]
Abstract
BACKGROUND Genetic abnormalities in the Fas receptor or its trimeric ligand, FasL, result in massive T-cell proliferation and a lupus-like autoimmune syndrome, which was initially attributed to excessive lymphoproliferation but is now ascribed to the absence of Fas-mediated cell death. Although Fas is normally expressed on most thymocytes, negative selection seems to be unperturbed in Fas-deficient (lpr) mice. This suggests that Fas has an important function in peripheral, but not thymic, T cells. RESULTS To explore the Fas-mediated cell death pathway both in vitro and in vivo, we used conditional alleles of the Fas receptor that can be triggered by an intracellularly active chemical inducer of dimerization known as FK1012. We found that membrane attachment is important for Fas function and, unlike previous results with anti-Fas monoclonal antibodies, we show that dimerization is sufficient to trigger apoptosis. Finally, the administration of FK1012 in vivo to transgenic animals expressing the conditional FAS receptor in thymocytes demonstrates that sensitivity to FAS-mediated apoptosis is restricted to CD4+CD8+ thymocytes. CONCLUSIONS Here, we describe the first in vivo application of non-toxic, cell-permeable synthetic ligands to regulate signal transduction in transgenic mice expressing a conditional receptor. Using this system, we show that the Fas pathway is restricted to double-positive thymocytes in vivo, consistent with recent in vitro findings with thymocytes. This method promises to be more useful not only for developmental studies involving cell ablation, but also for studies involving the regulation of a wide variety of signaling molecules.
Collapse
Affiliation(s)
- D M Spencer
- Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University Medical School, California 94305, USA.
| | | | | | | | | | | | | |
Collapse
|
13
|
Belshaw PJ, Ho SN, Crabtree GR, Schreiber SL. Controlling protein association and subcellular localization with a synthetic ligand that induces heterodimerization of proteins. Proc Natl Acad Sci U S A 1996; 93:4604-7. [PMID: 8643450 PMCID: PMC39324 DOI: 10.1073/pnas.93.10.4604] [Citation(s) in RCA: 211] [Impact Index Per Article: 7.5] [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] [Indexed: 02/01/2023] Open
Abstract
Extracellular growth and differentiation factors induce changes in gene expression in the nucleus by initiating a series of protein associations that alter the subcellular localization of intracellular signaling proteins. Initial events involve receptor homo- or heterodimerization and subsequent recruitment of cytosolic signaling proteins to the inner leaflet of the plasma membrane. Intermediate events involve the translocation of proteins into the nucleus. Late events involve the recruitment of transcriptional activators to the vicinity of specific genes in the nucleus, resulting in increased gene transcription. The ability to induce signals at each of these three phases of signaling pathways is illustrated by the use of a heterodimeric chemical inducer of dimerization that causes a proximal relationship between two different target proteins.
Collapse
Affiliation(s)
- P J Belshaw
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | | | | | | |
Collapse
|
14
|
Ho SN, Thomas DJ, Timmerman LA, Li X, Francke U, Crabtree GR. NFATc3, a lymphoid-specific NFATc family member that is calcium-regulated and exhibits distinct DNA binding specificity. J Biol Chem 1995; 270:19898-907. [PMID: 7650004 DOI: 10.1074/jbc.270.34.19898] [Citation(s) in RCA: 142] [Impact Index Per Article: 4.9] [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: 01/26/2023] Open
Abstract
Signals transduced by the T cell antigen receptor (TCR) regulate developmental transitions in the thymus and also mediate the immunologic activation of mature, peripheral T cells. In both cases TCR stimulation leads to the assembly of the NFAT transcription complex as a result of the calcium-dependent nuclear translocation of cytosolic subunits, NFATc, and the Ras/protein kinase C-dependent induction of a nuclear subunit, NFATn. To further understand the diverse roles of antigen receptor signaling throughout T cell development, we have identified a new NFATc family member, NFATc3, that is expressed at highest levels in the thymus. NFATc3 is the product of a gene on murine chromosome 8 that is not linked to the other NFATc genes. NFATc3, like other NFATc family members, contains a conserved rel similarity domain, and also defines a region conserved among NFATc family members, the SP repeat region, characterized by the repeated motif SPxxSPxxSPrxsxx (D/E)(D/E)swl. NFATc3 activates NFAT site-dependent transcription when overexpressed, yet exhibits a pattern of DNA site specificity distinct from other NFATc proteins. Additionally, thymic NFATc3 undergoes modifications in response to agents that mimic T cell receptor signaling, including a decrease in apparent molecular mass upon elevation of intracellular calcium that is inhibited by the immunosuppressant FK506. Given the preferential expression of NFATc3 in the thymus, NFATc family members may regulate distinct subsets of genes during T cell development.
Collapse
Affiliation(s)
- S N Ho
- Department of Developmental Biology, Howard Hughes Medical Institute, Stanford University Medical School, California 94305, USA
| | | | | | | | | | | |
Collapse
|
15
|
Li X, Ho SN, Luna J, Giacalone J, Thomas DJ, Timmerman LA, Crabtree GR, Francke U. Cloning and chromosomal localization of the human and murine genes for the T-cell transcription factors NFATc and NFATp. Cytogenet Cell Genet 1995; 68:185-91. [PMID: 7842733 DOI: 10.1159/000133910] [Citation(s) in RCA: 26] [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] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The nuclear factor of activated T cells (NFAT) is a transcription factor complex involved in the activation of cytokines and cell surface molecules associated with coordinating the actions of different cells required for an immune response. Two different genes have recently been cloned that encode proteins capable of functioning as the pre-existing (p) and cytosolic (c) component of the NFAT transcription complex, NFATc of human and NFATp of murine origin (Northrop et al., 1994; McCaffrey et al., 1993b). We report here the partial cDNA cloning of the murine homolog of NFATc and the human homolog of NFATp, and the chromosomal localization of both genes in both species to conserved syntenic regions. Through the use of mapping panels of human x Chinese hamster and mouse x rodent cells hybrids, the NFATc genes were mapped to human and mouse chromosomes 18. By analyzing a chromosome 18 radiation hybrid panel, the human NFATc gene was localized to the q terminus, closely linked to STS marker D18S497. The murine Nfatc gene was sublocalized to chromosome band 18E4 by FISH. The NFATp genes were mapped by somatic cell hybrid analysis to human chromosome 20 and mouse chromosome 2. Human NFATp was assigned to chromosome region 20q13.2-->q13.3 by FISH. Based on the conserved syntenic region on human chromosome 20 and mouse chromosome 2, murine Nfatp is predicted to reside in the vicinity of a mutant locus wasted. Homozygous wst/wst mice display a phenotype reminiscent of severe combined immune deficiency or ataxia telangiectasia, disorders that could therefore be considered candidates for NFATp mutations.
Collapse
Affiliation(s)
- X Li
- Howard Hughes Medical Institute, Stanford University Medical Center, CA 94305-5428
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Jayaraman G, Bhaskaran R, Yu C, Young JJ, Jung LJ, Liu WT, Ho SN, Chang LR. Three-dimensional structure in solution of griseoviridin, a group A antibiotic. Biochim Biophys Acta 1994; 1201:149-56. [PMID: 7947926 DOI: 10.1016/0304-4165(94)90035-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The solution conformation of griseoviridin, a broad spectrum antibiotic, has been determined by 1H-NMR in deuterated dimethylsulfoxide. The structural determination is based on experimental data of NOE constraints Five structures were obtained from restrained molecular dynamics calculations, by imposing (the condition for) a minimum violation of distance constraints. These structures satisfy well the experimental restraints, with small values of NOE violation and total energies. On comparison with its crystal structure, a good agreement is noted with a backbone root-mean-square deviation value of 0.084 nm. However, a small variation between the structures is observed at the aminodecanoic acid part of the molecule.
Collapse
Affiliation(s)
- G Jayaraman
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Ho SN, Boyer SH, Schreiber SL, Danishefsky SJ, Crabtree GR. Specific inhibition of formation of transcription complexes by a calicheamicin oligosaccharide: a paradigm for the development of transcriptional antagonists. Proc Natl Acad Sci U S A 1994; 91:9203-7. [PMID: 7937742 PMCID: PMC44780 DOI: 10.1073/pnas.91.20.9203] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [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: 01/28/2023] Open
Abstract
Sequence-specific DNA ligands that antagonize DNA-protein interactions represent a potentially powerful means of modulating gene expression. Calicheamicin gamma 1I, a member of the DNA-cleaving enediyne class of anticancer antibiotics, binds to specific DNA sequences through an aryltetrasaccharide domain. To take advantage of this unique sequence-specific recognition capability, the methyl glycoside of the aryltetrasaccharide of calicheamicin gamma 1I (CLM-MG) was used to investigate the ability of glycoconjugate DNA ligands to inhibit DNA-protein interactions. CLM-MG inhibits the formation of DNA-protein complexes at micromolar concentrations in a sequence-specific manner and rapidly dissociates preformed complexes. CLM-MG also inhibits transcription in vivo with similar sequence specificity. These results suggest a strategy for the development of a class of novel biological probes and therapeutic agents.
Collapse
Affiliation(s)
- S N Ho
- Department of Pathology, Stanford University School of Medicine, CA 94305
| | | | | | | | | |
Collapse
|
18
|
Young JJ, Jung LJ, Liu WT, Ho SN, Chang LR, Tsai YC, Bhaskaran R, Yu C. Solution conformation of enopeptin A, a depsipeptide antibiotic, using 2D NMR and restrained molecular dynamics studies. J Antibiot (Tokyo) 1994; 47:922-31. [PMID: 7928680 DOI: 10.7164/antibiotics.47.922] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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: 01/27/2023]
Abstract
Studies on the solution conformation of the cyclic depsipeptide antibiotic enopeptin A have been carried out using 2D NMR and molecular modelling techniques. The proton resonances of the antibiotic in DMSO-d6 have been assigned by the use of TOCSY and ROESY experiments. The interproton distance information obtained from the ROESY experiments have been used as the basis for elucidating the probable structures in solution. The restrained molecular dynamics technique was applied to calculate the structures in solution, and six resultant structures with fewer distance constraint violations were obtained that satisfy the experimental restraints very well. The conformation of the cyclic moiety of the molecules is well defined whereas the aliphatic chain segment is disordered.
Collapse
Affiliation(s)
- J J Young
- Institute of Preventive Medicine, National Defence Medical Center, Taipei, Taiwan, R.O.C
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Northrop JP, Ho SN, Chen L, Thomas DJ, Timmerman LA, Nolan GP, Admon A, Crabtree GR. NF-AT components define a family of transcription factors targeted in T-cell activation. Nature 1994; 369:497-502. [PMID: 8202141 DOI: 10.1038/369497a0] [Citation(s) in RCA: 468] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The NF-AT transcription complex is required for the expression of a group of proteins that collectively coordinate the immune response. Here we purify two proteins encoded by separate genes that represent the pre-existing (p) and cytosolic (c) components of NF-AT. Expression of the full-length complementary DNA encoding NF-ATc activates the interleukin (IL-2) promoter in non-T lymphocytes, whereas a dominant negative of NF-ATc specifically blocks activation of the IL-2 promoter in T lymphocytes, indicating that NF-ATc is required for IL-2 gene expression. NF-ATc RNA expression is largely restricted to lymphoid tissues and is induced upon T-cell activation. The other protein, NF-ATp, is highly homologous to NF-ATc over a limited domain which shows similarity to the Dorsal/Rel family, but has a wider tissue distribution. Agents that increase intracellular Ca2+ or activate protein kinase C independently modify NF-ATc, indicating that distinct signalling pathways converge on NF-ATc to regulate its function.
Collapse
Affiliation(s)
- J P Northrop
- Department of Developmental Biology, Howard Hughes Medical Institute, Stanford University Medical School, California 94305
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Young JJ, Ho SN, Ju WM, Chang LR. FL-120A-D', new products related to kinamycin from Streptomyces chattanoogensis subsp. taitungensis subsp. nov. II. Isolation and structure determination. J Antibiot (Tokyo) 1994; 47:681-7. [PMID: 8040073 DOI: 10.7164/antibiotics.47.681] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Six new kinamycin antibiotics have been isolated from the culture filtrate of Streptomyces chattanoogensis. The structures of six related components were determined employing 1D and 2D NMR spectroscopy and mass spectrometry. These structures represent the first reported epoxide kinamycin (2, 3) and propionyl derivative of kinamycin (5), and new isobutyryl derivatives of kinamycin (1, 4, 6).
Collapse
Affiliation(s)
- J J Young
- Division of Applied Chemistry, National Defense Medical Center, Taipei, Taiwan, R.O.C
| | | | | | | |
Collapse
|
21
|
Affiliation(s)
- R M Horton
- Department of Biochemistry, Gortner Laboratories, University of Minnesota, St. Paul 55108
| | | | | | | | | | | |
Collapse
|
22
|
Horton RM, Cai ZL, Ho SN, Pease LR. Gene splicing by overlap extension: tailor-made genes using the polymerase chain reaction. Biotechniques 1990; 8:528-35. [PMID: 2357375] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Gene Splicing by Overlap Extension or "gene SOEing" is a PCR-based method of recombining DNA sequences without reliance on restriction sites and of directly generating mutated DNA fragments in vitro. By modifying the sequences incorporated into the 5'-ends of the primers, any pair of polymerase chain reaction products can be made to share a common sequence at one end. Under polymerase chain reaction conditions, the common sequence allows strands from two different fragments to hybridize to one another, forming an overlap. Extension of this overlap by DNA polymerase yields a recombinant molecule. This powerful and technically simple approach offers many advantages over conventional approaches for manipulating gene sequences.
Collapse
Affiliation(s)
- R M Horton
- Dept. of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905
| | | | | | | |
Collapse
|
23
|
Ruegemer JJ, Ho SN, Augustine JA, Schlager JW, Bell MP, McKean DJ, Abraham RT. Regulatory effects of transforming growth factor-beta on IL-2- and IL-4-dependent T cell-cycle progression. J Immunol 1990; 144:1767-76. [PMID: 2407783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Previous studies suggested that the potent immunosuppressive activities of transforming growth factor-beta (TGF-beta) were mediated in part through the inhibition of IL-2-dependent S-phase progression and mitosis of activated T cells. To further investigate the mechanism of T cell growth inhibition by TGF-beta, two constitutively activated murine T cell clones were employed as defined model systems for the growth factor-dependent phase of T cell proliferation. The Th cell line, HT-2, proliferated in response to either IL-2 or IL-4, whereas the cytotoxic T cell line, CT6, exhibited strict dependence on IL-2 for growth stimulation. In both cell lines, picomolar concentrations of TGF-beta inhibited S-phase progression stimulated by IL-2 or IL-4. TGF-beta pretreatment decreased the expression of high affinity IL-2R on HT-2 cells, but not on CT6 cells. In contrast, IL-2-stimulated transferrin receptor expression was markedly inhibited by TGF-beta in both T cell lines. Analyses of growth factor-dependent specific mRNA accumulation revealed that TGF-beta exerted selective inhibitory effects on gene expression in HT-2 and CT6 cells. TGF-beta significantly reduced early (1 to 2 h) increases in c-myc mRNA levels stimulated by IL-2 or IL-4 in both cell lines. In HT-2 cells, TGF-beta pretreatment also inhibited the early increase in granulocyte-macrophage CSF mRNA stimulated by IL-2 or IL-4. The inhibition of c-myc and granulocyte-macrophage cyte-macrophage CSF gene expression by TGF-beta was explained, at least in part, by suppression of the growth factor-dependent transcriptional activation of these genes. These studies suggest that inhibition of c-myc gene transcription may play a fundamental role in the antiproliferative effect of TGF-beta on IL-2- or IL-4-stimulated T cells.
Collapse
Affiliation(s)
- J J Ruegemer
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
| | | | | | | | | | | | | |
Collapse
|
24
|
Ruegemer JJ, Ho SN, Augustine JA, Schlager JW, Bell MP, McKean DJ, Abraham RT. Regulatory effects of transforming growth factor-beta on IL-2- and IL-4-dependent T cell-cycle progression. The Journal of Immunology 1990. [DOI: 10.4049/jimmunol.144.5.1767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Previous studies suggested that the potent immunosuppressive activities of transforming growth factor-beta (TGF-beta) were mediated in part through the inhibition of IL-2-dependent S-phase progression and mitosis of activated T cells. To further investigate the mechanism of T cell growth inhibition by TGF-beta, two constitutively activated murine T cell clones were employed as defined model systems for the growth factor-dependent phase of T cell proliferation. The Th cell line, HT-2, proliferated in response to either IL-2 or IL-4, whereas the cytotoxic T cell line, CT6, exhibited strict dependence on IL-2 for growth stimulation. In both cell lines, picomolar concentrations of TGF-beta inhibited S-phase progression stimulated by IL-2 or IL-4. TGF-beta pretreatment decreased the expression of high affinity IL-2R on HT-2 cells, but not on CT6 cells. In contrast, IL-2-stimulated transferrin receptor expression was markedly inhibited by TGF-beta in both T cell lines. Analyses of growth factor-dependent specific mRNA accumulation revealed that TGF-beta exerted selective inhibitory effects on gene expression in HT-2 and CT6 cells. TGF-beta significantly reduced early (1 to 2 h) increases in c-myc mRNA levels stimulated by IL-2 or IL-4 in both cell lines. In HT-2 cells, TGF-beta pretreatment also inhibited the early increase in granulocyte-macrophage CSF mRNA stimulated by IL-2 or IL-4. The inhibition of c-myc and granulocyte-macrophage cyte-macrophage CSF gene expression by TGF-beta was explained, at least in part, by suppression of the growth factor-dependent transcriptional activation of these genes. These studies suggest that inhibition of c-myc gene transcription may play a fundamental role in the antiproliferative effect of TGF-beta on IL-2- or IL-4-stimulated T cells.
Collapse
Affiliation(s)
- J J Ruegemer
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
| | - S N Ho
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
| | - J A Augustine
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
| | - J W Schlager
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
| | - M P Bell
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
| | - D J McKean
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
| | - R T Abraham
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
| |
Collapse
|
25
|
Abstract
Gene splicing by overlap extension is a new approach for recombining DNA molecules at precise junctions irrespective of nucleotide sequences at the recombination site and without the use of restriction endonucleases or ligase. Fragments from the genes that are to be recombined are generated in separate polymerase chain reactions (PCRs). The primers are designed so that the ends of the products contain complementary sequences. When these PCR products are mixed, denatured, and reannealed, the strands having the matching sequences at their 3' ends overlap and act as primers for each other. Extension of this overlap by DNA polymerase produces a molecule in which the original sequences are 'spliced' together. This technique is used to construct a gene encoding a mosaic fusion protein comprised of parts of two different class-I major histocompatibility genes. This simple and widely applicable approach has significant advantages over standard recombinant DNA techniques.
Collapse
Affiliation(s)
- R M Horton
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905
| | | | | | | | | |
Collapse
|
26
|
Abstract
Overlap extension represents a new approach to genetic engineering. Complementary oligodeoxyribonucleotide (oligo) primers and the polymerase chain reaction are used to generate two DNA fragments having overlapping ends. These fragments are combined in a subsequent 'fusion' reaction in which the overlapping ends anneal, allowing the 3' overlap of each strand to serve as a primer for the 3' extension of the complementary strand. The resulting fusion product is amplified further by PCR. Specific alterations in the nucleotide (nt) sequence can be introduced by incorporating nucleotide changes into the overlapping oligo primers. Using this technique of site-directed mutagenesis, three variants of a mouse major histocompatibility complex class-I gene have been generated, cloned and analyzed. Screening of mutant clones revealed at least a 98% efficiency of mutagenesis. All clones sequenced contained the desired mutations, and a low frequency of random substitution estimated to occur at approx. 1 in 4000 nt was detected. This method represents a significant improvement over standard methods of site-directed mutagenesis because it is much faster, simpler and approaches 100% efficiency in the generation of mutant product.
Collapse
Affiliation(s)
- S N Ho
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
| | | | | | | | | |
Collapse
|
27
|
Beck BN, Ho SN. Increased specificity of PCR-amplified products by size-fractionation of restriction enzyme-digested template genomic DNA. Nucleic Acids Res 1988; 16:9051. [PMID: 3174445 PMCID: PMC338661 DOI: 10.1093/nar/16.18.9051] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- B N Beck
- Department of Immunology, Mayo Clinic, Rochester, MN 55902
| | | |
Collapse
|
28
|
Ho SN, Abraham RT, Nilson A, Handwerger BS, McKean DJ. Interleukin 1-mediated activation of interleukin 4 (IL 4)-producing T lymphocytes. Proliferation by IL 4-dependent and IL 4-independent mechanisms. J Immunol 1987; 139:1532-40. [PMID: 3114369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The role of IL 1 in the activation of IL 4-producing murine T cell clones was investigated by using a calcium ionophore (ionomycin) or a phorbol ester (12-O-tetradecanoylphorbol 13-acetate; TPA) as T cell receptor-independent costimuli. The use of these pharmacologic agents to investigate IL 1-mediated T cell activation revealed two distinct mechanisms of activation. IL 1 in combination with ionomycin (iono/rIL 1) stimulated a proliferative response that was associated with the production of IL 4 as measured by lymphokine bioassay and mRNA studies. Furthermore, inhibition of this proliferative response with an anti-IL 4 monoclonal antibody or cyclosporine indicated that IL 4 functions as an autocrine growth factor. In contrast, IL 1 synergized with TPA (TPA/rIL 1) to induce proliferation in the absence of either IL 4 or IL 2 gene transcription or lymphokine secretion. The IL 4-independence of this activation mechanism was further supported by the failure of both anti-IL 4 antibodies and cyclosporine to inhibit the response. In addition, activation by TPA/rIL 1 caused no detectable alteration in cytoplasmic calcium levels. Both IL 4-dependent and IL 4-independent activation responses were associated with the expression of functional receptors for IL 2 as well as IL 4. Characterization of these activation responses suggests that the synergistic activity of IL 1 during T cell activation is multipotential. The nature of an IL 1-dependent T cell growth response, therefore, may vary depending on the balance of intracellular signals generated concurrently through the T cell receptor complex and other regulatory surface molecules.
Collapse
|
29
|
Ho SN, Abraham RT, Nilson A, Handwerger BS, McKean DJ. Interleukin 1-mediated activation of interleukin 4 (IL 4)-producing T lymphocytes. Proliferation by IL 4-dependent and IL 4-independent mechanisms. The Journal of Immunology 1987. [DOI: 10.4049/jimmunol.139.5.1532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
The role of IL 1 in the activation of IL 4-producing murine T cell clones was investigated by using a calcium ionophore (ionomycin) or a phorbol ester (12-O-tetradecanoylphorbol 13-acetate; TPA) as T cell receptor-independent costimuli. The use of these pharmacologic agents to investigate IL 1-mediated T cell activation revealed two distinct mechanisms of activation. IL 1 in combination with ionomycin (iono/rIL 1) stimulated a proliferative response that was associated with the production of IL 4 as measured by lymphokine bioassay and mRNA studies. Furthermore, inhibition of this proliferative response with an anti-IL 4 monoclonal antibody or cyclosporine indicated that IL 4 functions as an autocrine growth factor. In contrast, IL 1 synergized with TPA (TPA/rIL 1) to induce proliferation in the absence of either IL 4 or IL 2 gene transcription or lymphokine secretion. The IL 4-independence of this activation mechanism was further supported by the failure of both anti-IL 4 antibodies and cyclosporine to inhibit the response. In addition, activation by TPA/rIL 1 caused no detectable alteration in cytoplasmic calcium levels. Both IL 4-dependent and IL 4-independent activation responses were associated with the expression of functional receptors for IL 2 as well as IL 4. Characterization of these activation responses suggests that the synergistic activity of IL 1 during T cell activation is multipotential. The nature of an IL 1-dependent T cell growth response, therefore, may vary depending on the balance of intracellular signals generated concurrently through the T cell receptor complex and other regulatory surface molecules.
Collapse
|
30
|
Abstract
The T cell-derived lymphokines interleukin 2 (IL-2) and interleukin 4 (IL-4, originally BSF-1) both exhibit T cell growth-promoting activity. Recent observations that T cell lines commonly used as indicator cells in IL-2 bioassays also proliferate in response to IL-4 demonstrate the lack of specificity of these bioassays for IL-2. In this report we describe a bioassay method to differentiate IL-2 and IL-4 through the parallel use of two T cell lines with defined lymphokine specificity. The IL-2-responsive CT6 cell line, when used in conjunction with the IL-2- and IL-4-responsive HT-2 cell line, allows for the differentiation of IL-2 and IL-4 in conditioned media.
Collapse
|
31
|
Abraham RT, Ho SN, Barna TJ, McKean DJ. Transmembrane signaling during interleukin 1-dependent T cell activation. Interactions of signal 1- and signal 2-type mediators with the phosphoinositide-dependent signal transduction mechanism. J Biol Chem 1987; 262:2719-28. [PMID: 3029093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The murine T lymphoma line, LBRM-33 1A5, requires synergistic signals delivered by phytohemagglutinin (PHA) and interleukin 1 (IL1) for activation to high level interleukin 2 production. The activation signals provided by PHA and IL1 were replaced by the Ca2+ ionophore, ionomycin, and the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA), respectively. These observations supported a two-signal model for T cell activation involving increases in intracellular Ca2+ concentration ([Ca2+]i) (signal 1) and activation of protein kinase C (signal 2) as necessary and sufficient events. However, biochemical analyses revealed that additional signals were involved in the activation of LBRM-33 cells by both receptor-dependent and -independent mediators. Both signal 1-type mediators, PHA and ionomycin, exerted pleiotropic effects at the concentrations required for synergy with signal 2-type mediators (IL1, TPA). Within 1-2 min of addition, PHA stimulated phospholipid turnover, including hydrolysis of phosphatidylinositol 4,5-bisphosphate, Ca2+ mobilization, and protein kinase C activation. The [Ca2+]i increase induced by PHA was due to influx from both intracellular and extracellular Ca2+ pools. Similarly, ionomycin increased phospholipid turnover, [Ca2+]i, and directly affected protein kinase C activity in LBRM-33 cells. In contrast, the signal 2-type mediators, TPA and IL1, appeared to act by distinct intracellular mechanisms. TPA induced a protracted association of cellular protein kinase C with the plasma membrane, consistent with the two-signal activation model. Furthermore, acute TPA treatment inhibited PHA-stimulated inositol phosphate release and Ca2+ mobilization, suggesting that this mediator partially antagonized signal 1 delivery. IL1, in contrast, neither activated protein kinase C directly nor did it positively modulate the coupling of signal 1-type mediators to [Ca2+]i or protein kinase C via the phosphoinositide pathway. The intracellular signal delivered by IL1 is, therefore, generated through a mechanism distinct from or distal to the activation of protein kinase C. These studies indicate that the two-signal hypothesis, in its simplest form, is inadequate to explain the signals required for the initiation of IL1-dependent T cell activation.
Collapse
|