1
|
Salmons B, Gunzburg WH. Release characteristics of cellulose sulphate capsules and production of cytokines from encapsulated cells. Int J Pharm 2018; 548:15-22. [PMID: 29933063 DOI: 10.1016/j.ijpharm.2018.06.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 06/16/2018] [Accepted: 06/18/2018] [Indexed: 12/11/2022]
Abstract
The size and speed of release of proteins of different sizes from standard cellulose sulphate capsules (Cell-in-a-Box®) was investigated. Proteins with molecular weights of up to around 70kD can be released. The conformation, charge and concentration of the protein being released play a role in the release kinetics. Small proteins such as cytokines can be easily released. The ability to produce cytokines at a sustained and predefined level from encapsulated cells genetically engineered to overexpress such cytokines and implanted into patients may aid immunotherapies of cancer as well as infectious and other diseases. It will also allow allogeneic rather than autologous cells to be used. We show that cells encapsulated in polymers of cellulose sulphate are able to release cytokines such as interleukin-2 (IL-2) in a stimulated fashion e.g. using phorbol 12-myristate 13-acetate (PMA) plus ionomycin. Given the excellent documented safety record of cellulose sulphate in patients, these data suggest that clinical usage of the technology may be warranted for cancer treatment and other diseases.
Collapse
Affiliation(s)
- Brian Salmons
- Austrianova Singapore Pte Ltd, Synapse, 3 Biopolis Drive, Singapore
| | - Walter H Gunzburg
- Austrianova Singapore Pte Ltd, Synapse, 3 Biopolis Drive, Singapore; Institute of Virology, Dept. of Pathobiology, University of Veterinary Medicine, A1210 Vienna, Austria.
| |
Collapse
|
2
|
Vasilev F, Chun JT, Gragnaniello G, Garante E, Santella L. Effects of ionomycin on egg activation and early development in starfish. PLoS One 2012; 7:e39231. [PMID: 22723970 PMCID: PMC3377674 DOI: 10.1371/journal.pone.0039231] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 05/21/2012] [Indexed: 11/21/2022] Open
Abstract
Ionomycin is a Ca2+-selective ionophore that is widely used to increase intracellular Ca2+ levels in cell biology laboratories. It is also occasionally used to activate eggs in the clinics practicing in vitro fertilization. However, neither the precise molecular action of ionomycin nor its secondary effects on the eggs' structure and function is well known. In this communication we have studied the effects of ionomycin on starfish oocytes and zygotes. By use of confocal microscopy, calcium imaging, as well as light and transmission electron microscopy, we have demonstrated that immature oocytes exposed to ionomycin instantly increase intracellular Ca2+ levels and undergo structural changes in the cortex. Surprisingly, when microinjected into the cells, ionomycin produced no Ca2+ increase. The ionomycin-induced Ca2+ rise was followed by fast alteration of the actin cytoskeleton displaying conspicuous depolymerization at the oocyte surface and in microvilli with concomitant polymerization in the cytoplasm. In addition, cortical granules were disrupted or fused with white vesicles few minutes after the addition of ionomycin. These structural changes prevented cortical maturation of the eggs despite the normal progression of nuclear envelope breakdown. At fertilization, the ionomycin-pretreated eggs displayed reduced Ca2+ response, no elevation of the fertilization envelope, and the lack of orderly centripetal translocation of actin fibers. These alterations led to difficulties in cell cleavage in the monospermic zygotes and eventually to a higher rate of abnormal development. In conclusion, ionomycin has various deleterious impacts on egg activation and the subsequent embryonic development in starfish. Although direct comparison is difficult to make between our findings and the use of the ionophore in the in vitro fertilization clinics, our results call for more defining investigations on the issue of a potential risk in artificial egg activation.
Collapse
Affiliation(s)
- Filip Vasilev
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
| | - Jong T. Chun
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
| | - Giovanni Gragnaniello
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
| | - Ezio Garante
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
| | - Luigia Santella
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
- * E-mail:
| |
Collapse
|
3
|
Wang J, Cong L, Zhang ZG, Cao YX, Wei ZL, Zhou P, Zhao JH, He XJ. [Effect of double activation on the development of frozen-thawed oocytes after intracytoplasmic sperm injection]. Zhonghua Fu Chan Ke Za Zhi 2009; 44:135-138. [PMID: 19570426] [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] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVE To investigate the influence on developmental potential of frozen-thawed rabbit oocytes with double assisted activation followed by intracytoplasmic sperm injection (ICSI). METHODS A total of rabbit oocytes were collected and thawed after vitrification cryopreservation. Among all oocytes were cultured for 1 hour followed by ICSI. 156 Survived oocytes were divided into 5 groups randomly. I0634 single activation: 30 oocytes were added with calcium ionomycin (I0634) at 5 micromol/L for 5 minutes; SrCl(2) single activation: 26 oocytes were added with strontium chloride at 10 mmol/L for 10 minutes; I0634 double activation: 33 oocytes were activated by I0634 twice; SrCl(2) double activation: 28 oocytes were activated by strontium chloride twice. CONTROL GROUP 39 oocytes were not added with any activators. The rate of fertilization, cleavage and blastocysts formation were observed and compared between various groups. RESULT The rates of fertilization, cleavage and blastocysts formation were in group of SrCl(2) single activation were higher than those of I0634 single activation group without statistical difference (54% vs.33%, 27% vs. 17%, 8% vs. 3%, P < 0.05). However, those above rates in double activation by I0634 were higher significantly than those of single I0634 activation (82% vs. 33%, 55% vs. 17%, 15% vs. 3%, P < 0.05). The rates of fertilization (61%) was higher and the rate of cleavage (21%) and blastocysts formation (7%) were lower in group of SrCl(2) double activation in comparison with group of SrCl(2) single activation without reaching statistical difference (P < 0.05). Notably, the rates of fertilization, cleavage and blastocysts formation in I0634 double activation group were higher than those in group of SrCl(2) double activation with statistical difference (82% vs. 61%, 55% vs. 21%, 15% vs. 7%, P < 0.05). CONCLUSION It might enhance the potential of fertilization of oocytes and early embryo development treated by double activation following ICSI, however, those activated oocytes demonstrate rapid cleavage.
Collapse
Affiliation(s)
- Jing Wang
- Reproductive Center, First Affiliated Hospital of Anhui Medical University, Hefei 230022, China
| | | | | | | | | | | | | | | |
Collapse
|
4
|
Khaidukov SV, Litvinov IS. Calcium homeostasis change in CD4+ T lymphocytes from human peripheral blood during differentiation in vivo. Biochemistry (Mosc) 2005; 70:692-702. [PMID: 16038612 DOI: 10.1007/s10541-005-0170-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Resting naïve CD4+(CD45R0-)CD45RA+ T cells are sensitive to ionomycin. In contrast, resting CD4+(CD45RA-)CD45R0+ memory T cells show resistance to this Ca2+ ionophore. In the present study, the ability of activated T lymphocytes to respond to ionomycin during the transition from naïve precursors into memory T cells has been analyzed. Activated CD4+(CD45RA+)CD45R0+ T cells are always present both in human peripheral blood (HPB) and in the ionomycin-resistant (IR) fraction. Therefore, some activated T cells are resistant toward the Ca2+ ionophore. CD69 molecules are markers of the very early stage of T cell activation. However, CD4+CD69+ T cells have never been found in the IR fraction. Thus, the majority of CD4+ T lymphocytes at the early stage of activation are ionomycin-sensitive cells. The proportion of CD4+CD25+ T cells did not differ significantly in HPB and in the IR fraction. The presence of CD4+CD25+ T lymphocytes in the IR fraction reflects changes in the Ca2+-signaling pathway at this differentiation step of activated cells. Depending on the expression level of CD25 molecules, the population of CD4+CD25+ cells is divided in T-regulatory (CD25high) and proliferating (CD25low) subpopulations. The action of ionomycin results in a decrease in the portion of the CD4+CD25low T-cells, but it leads to an increase in the proportion of the CD4+CD25high T lymphocytes. Consequently, greater portion of CD4+CD25high T lymphocytes and smaller portion of CD4+CD25low T cells are IR cells. Expression of HLA-DR molecules can be used as the marker for the late activation step. The IR fraction is significantly rich in CD4+HLA-DR+ T lymphocytes in comparison to the blood of the same donor. The link between different differentiation steps of CD4+ T-lymphocytes and alterations in calcium ion homeostasis is discussed.
Collapse
Affiliation(s)
- S V Khaidukov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | | |
Collapse
|
5
|
Oikawa T, Takada N, Kikuchi T, Numabe T, Takenaka M, Horiuchi T. Evaluation of activation treatments for blastocyst production and birth of viable calves following bovine intracytoplasmic sperm injection. Anim Reprod Sci 2005; 86:187-94. [PMID: 15766799 DOI: 10.1016/j.anireprosci.2004.07.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2003] [Revised: 05/07/2004] [Accepted: 07/20/2004] [Indexed: 11/23/2022]
Abstract
The objective of this study was to compare the effectiveness of different methods of bovine oocyte activation following intracytoplasmic sperm injection (ICSI) in terms of oocyte cleavage and blastocyst rates, and calf production. Oocytes were harvested, post mortem, from the ovaries of Japanese Black heifers or cows. ICSI was carried out using a piezo-electric actuator. The injected or sham-injected oocytes that were assigned to three activation treatments, each replicated three times, were studied: (1) exposure to 5 microM ionomycin for 5 min (ionomycin); (2) exposure to 5 microM ionomycin for 5 min followed by culture in TCM199 for 3 h and a further 3h culture in 1.9 mM 6-dimethylaminopurine (DMAP-ionomycin+DMAP); (3) exposure to 7% ethanol in TCM199 for 5 min, 4 h after ICSI (ethanol). One or two blastocysts from the ionomycin+DMAP (8 recipients) and ethanol (17 recipients) oocyte activation treatments were non-surgically transferred into Holsteins for the study of calf production. The highest cleavage and blastocyst production rates were observed in the ionomycin+DMAP treatment (83.9% and 40.1%) by the ICSI. These rates were significantly (P<0.05) higher than those for the ionomycin oocyte activation treatment (57.6% and 18.2%) but did not differ from the ethanol treatment (75.6% and 29.4%). In the sham-injected, the highest blastocyst production rates were observed for the ionomycin+DMAP and ethanol treatments (10.7% and 11.3%). Pregnancy and birth rates for blastocysts derived from the ethanol oocyte activation treatment (58.8% and 47.4%) were significantly higher (P<0.05) than those of the ionomycin+DMAP treatment (12.5% and 9.2%). The results showed that post-ICSI oocyte activation with ethanol is more effective than activation with ionomycin alone or with ionomycin+DMAP for the production of viable blastocysts and calves.
Collapse
Affiliation(s)
- T Oikawa
- Miyagi Prefecture Animal Industry Experiment Station, Miyagi 989-6445, Japan
| | | | | | | | | | | |
Collapse
|
6
|
Abstract
This study was carried out to compare the effects of the combination of ionomycin with a H1-histone kinase inhibitor (dimethylaminopurine, DMAP) or cdc2 kinase inhibitor (sodium pyrophosphate, SPP) on the development of reconstituted bovine eggs. For this study, the enucleated bovine oocytes were injected with a presumptive primordial germ cell pre-treated with 1% sodium citrate, and randomly allocated into three activation groups: Group 1 (ionomycin 5 microm, 5 min), Group 2 (ionomycin + DMAP 1.9 mm, 3 h), and Group 3 (ionomycin + SPP 2 mm, 3 h). The reconstituted eggs were compared on the rates of cleavage and development with the blastocyst stage and the ploidy of embryos at 96 h post-activation. Cleavage rates and blastocyst development in Groups 1, 2 and 3 were 7 and 0%, 63 and 17%, and 53 and 14%, respectively. The chromosomal composition differed significantly (p < 0.05) among treatments. Although the embryos in Group 1 had significantly lower developments, 60% of embryos evaluated had diploid chromosomal sets. In contrast, approximately 60% of embryos in Group 2 had abnormal ploidy (21% polyploid and 38% mixoploid). In Group 3, the appearance of abnormal chromosome sets was reduced with the proportion of diploid embryos being increased to 86% (19 of 22), significantly higher (p < 0.05) than in Group 2. It can be concluded that the use of SPP with ionomycin reduces greatly the incidence of chromosomal abnormalities, and may be applicable for the activation of nuclear transplant bovine embryos.
Collapse
Affiliation(s)
- J G Yoo
- College of Veterinary Medicine, Gyeongsang National University, Chinju, Korea
| | | | | |
Collapse
|
7
|
Barten MJ, Gummert JF, van Gelder T, Shorthouse R, Morris RE. Flow cytometric quantitation of calcium-dependent and -independent mitogen-stimulation of T cell functions in whole blood: inhibition by immunosuppressive drugs in vitro. J Immunol Methods 2001; 253:95-112. [PMID: 11384672 DOI: 10.1016/s0022-1759(01)00369-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [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: 10/18/2022]
Abstract
We have optimized assays to measure mitogen-stimulated rat lymphocyte activation in whole blood and have used these assays to quantitate the potencies of immunosuppressive drugs with different mechanisms of action. To define the optimal conditions for measuring T cell functions in whole blood, the effects of different concentrations of mitogens that activate T cells through calcium-dependent and -independent pathways were measured over time. Proliferation was measured by tritium-labeled thymidine ([3H]-TdR) incorporation and by flow cytometric analysis of proliferating cell nuclear antigen (PCNA)/DNA content. Furthermore, we detected the increases in percent expression of cell-surface activation antigens (CD25, CD134, CD71, CD11a and CD54). Concanavalin A (Con A) stimulated maximum lymphocyte proliferation and expression of T cell surface activations by 72-96 h, which was 48 h later than stimulation by phorbol 12-myristate 13-acetate (PMA) plus anti-CD28 monoclonal antibody (mAb) or PMA plus ionomycin (IONO). Addition of sirolimus, tacrolimus, cyclosporine or the active metabolite of leflunomide, A77 1726, to mitogen-stimulated whole blood produced drug concentration-dependent inhibitions of lymphocyte proliferation and expression of cell surface activation antigen expression. From these data, we determined drug potencies (inhibitory concentration of 50%, IC(50)) and drug concentrations causing maximum inhibition of T cell functions (I(max)). We developed simple and reproducible assays to measure different lymphocyte functions in whole blood cultures. These assays were used to investigate the mechanisms of different immunosuppressive drugs. These methods can be exploited to measure T cell functions in blood collected from subjects treated with immunosuppressants in vivo.
Collapse
Affiliation(s)
- M J Barten
- Transplantation Immunology, Department of Cardiothoracic Surgery, Stanford University Medical School, 94305-5407, Stanford, CA, USA
| | | | | | | | | |
Collapse
|
8
|
Cooper RS, Cheng HY, Rotimi C. Basal and stimulated platelet calcium and sodium in hypertensive versus normotensive black people. J Hum Hypertens 1995; 9:747-52. [PMID: 8551489] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To examine further the potential role of intracellular cations in hypertension a nested case-control study was carried out in conjunction with a population-based survey. Based on a house-to-house sampling scheme, 43 hypertensive and 56 normotensive black residents of Maywood, IL, were recruited. Free cytosolic calcium (Cai) and intracellular stores of calcium after stimulation with ionomycin were determined in platelets with the fluoroprobe Indo-I; intracellular sodium (Nai) measured at rest and after incubation with ouabain was estimated with SBFI. Cell sodium content was also assayed in erythrocytes. Resting Cai and Nai were not different in hypertensives compared with normotensives, although ionomycin-stimulated levels of Cai were correlated with systolic blood pressure (r = 0.3; P = 0.04). A consistent set of inter-relations among the various cation parameters was observed, lending support to the hypothesis that the cellular metabolism of sodium and calcium may be linked in the pathophysiological pathway to hypertension.
Collapse
Affiliation(s)
- R S Cooper
- Department of Preventive Medicine and Epidemiology, Loyola University School of Medicine, Maywood, IL 60153, USA
| | | | | |
Collapse
|
9
|
Rajasekar R, Augustin A. Selective proliferation of gamma delta T lymphocytes exposed to high doses of ionomycin. J Immunol 1992; 149:818-24. [PMID: 1321852] [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] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The alpha beta T cell repertoire is primarily shaped in the thymus. However, extrathymic positive selection has been demonstrated for many gamma delta T cell clonotypes. This latter type of selection is the result of a peripheral clonal expansion which could be facilitated by special physiological properties of gamma delta T cells, distinguishing them from most alpha beta T cells. In studying the behavior of T cells under conditions of polyclonal activation, we noticed a differential sensitivity between alpha beta and gamma delta T cells to strong stimulatory signals. When induced with high doses of ionomycin, a large fraction of peripheral gamma delta T cells and a small fraction of alpha beta T cells are able to proliferate exponentially while most alpha beta T cells die. This phenomenon appears to be related to intracellular regulation of high concentrations of cytosolic Ca2+. The ability to proliferate under strong stimulatory conditions is a striking feature of many peripheral gamma delta T cells but not of gamma delta thymocytes. In general, T cells selected in the periphery by clonal expansion might be characterized by resistance to strong stimuli and typically, by their ability to "handle" higher concentrations of free cytoplasmic calcium.
Collapse
MESH Headings
- Animals
- CD4 Antigens/analysis
- CD8 Antigens/analysis
- Calcium/metabolism
- Cell Death/drug effects
- Cytoplasm/metabolism
- Dose-Response Relationship, Drug
- Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor
- Ionomycin/administration & dosage
- Lymph Nodes/cytology
- Lymphocyte Activation/drug effects
- Mice
- Mice, Inbred BALB C
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, gamma-delta/genetics
- Receptors, Antigen, T-Cell, gamma-delta/metabolism
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
Collapse
Affiliation(s)
- R Rajasekar
- Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
| | | |
Collapse
|
10
|
Winter MC, Peterson MW, Shasby DM. Synergistic effects of a calcium ionophore and activators of protein kinase C on epithelial paracellular permeability. Am J Respir Cell Mol Biol 1991; 4:470-7. [PMID: 1902358 DOI: 10.1165/ajrcmb/4.5.470] [Citation(s) in RCA: 9] [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: 12/29/2022] Open
Abstract
Oxidants reversibly increase the paracellular permeability of Madin Darby canine kidney (MDCK) epithelial cell monolayers, and the decrease in resistance occurs within 10 to 15 min of initiating oxidant exposure. Oxidants also initiate hydrolysis of phosphatidylinositol in MDCK cells, with resultant increases in diacylglycerol and inositol phosphates. Phorbol esters and synthetic diacylglycerols increase the paracellular permeability of MDCK monolayers with a time course similar to the oxidants. In contrast, calcium ionophores increase MDCK monolayer paracellular permeability only after 2 to 3 h of exposure. Because the products of the oxidant-initiated phospholipid hydrolysis would be likely to both activate protein kinase C and increase cell calcium, we asked if ionomycin, a calcium ionophore, and phorbol esters or diacylglycerols, activators of protein kinase C, might not act in concert to alter MDCK monolayer paracellular permeability. When ionomycin was added alone to MDCK monolayers, there was an increase in cell calcium, activation of a lumen negative current, a limited transitory decrease in transepithelial resistance, but no increase in mannitol flux across the monolayers. When phorbol dibutyrate (PDBU) or oleyl acetyl glycerol (OAG) were added to MDCK monolayers, there was no current activated, there was a progressive decrease in transepithelial resistance, and there was an increase in mannitol flux across the monolayers which was evident within 20 to 40 min of adding the agent. When 1 microM ionomycin was added to the monolayers along with PDBU or OAG, there was a synergistic increase in paracellular permeability of the monolayers when compared to addition of ionomycin, PDBU, or OAG alone.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- M C Winter
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242
| | | | | |
Collapse
|
11
|
William F, Wagner F, Karin M, Kraft AS. Multiple doses of diacylglycerol and calcium ionophore are necessary to activate AP-1 enhancer activity and induce markers of macrophage differentiation. J Biol Chem 1990; 265:18166-71. [PMID: 2120223] [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: 12/30/2022] Open
Abstract
In contrast to phorbol esters, multiple doses of diacylgycerols are needed to differentiate U937 human monoblastic leukemic cells to a macrophage-like phenotype. Although both of these agents similarly activate protein kinase C in vitro, it is not known why these agents appear to have differing biologic effects. One possibility is that they regulate gene transcription in slightly different ways. Regulation of gene transcription by phorbol esters is complex and involves the stimulation of the transactivating proteins Jun and Fos which form dimers and bind to the AP-1 enhancer elements (5'-TGAGTCA-3'). To understand whether diacylglycerols regulate gene transcription similarly to phorbol esters and to examine whether activation of AP-1 enhancer activity is correlated with differentiation, we have treated U937 human monoblastic leukemic cells with these agents and examined activation of transcription from AP-1 enhancer elements. We find that, although a single dose of diacylglycerol, like phorbol esters, is sufficient to elevate mRNA levels of both the c-jun and c-fos protooncogenes, in contrast to phorbol esters there is no increase in either Jun protein or activation of AP-1 enhancer activity. However, multiple doses of this agent given over 24 h stimulate repeated elevations in c-jun and c-fos mRNA, increases in Jun protein, and enhancer activation. Treatment of U937 cells with ionomycin, a calcium ionophore, also stimulates an increase in c-jun mRNA, but neither activates AP-1 enhancer activity nor stimulates differentiation of these cells. However ionomycin functions to enhance the effects of diacylglycerols both on transcriptional activation and U937 differentiation. These results suggest a complex regulation of AP-1 enhancer activity in U937 cells by diacylglycerols involving both transcriptional and post-transcriptional regulatory mechanisms. Maximal activation of AP-1 enhancer elements, and not changes in jun and fos mRNA, is correlated with increases in markers of U937 differentiation. These changes may be important in the early events leading to differentiation of hematopoietic cells.
Collapse
Affiliation(s)
- F William
- Division of Hematology/Oncology, University of Alabama, Birmingham 35294
| | | | | | | |
Collapse
|
12
|
Lagoo A, Tseng CK, Sell S. Molecular signals in B cell activation. I. Differential refractory effects of incomplete signaling by ionomycin or PMA relate to autocrine IL-2 production and IL-2R expression. Cell Immunol 1990; 127:483-96. [PMID: 2328535 DOI: 10.1016/0008-8749(90)90148-k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [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: 12/31/2022]
Abstract
The molecular signals required by resting (G0) B cells for the induction of cell cycle entry, IL-2 production, and high-affinity IL-2 receptor (IL-2R) expression were defined and the effects of incomplete activation signals on the subsequent response to complete signals were examined. Highly enriched rabbit peripheral blood B cells were activated with a calcium ionophore, ionomycin, and a protein kinase C (PKC) activating phorbol ester, phorbol myristate acetate (PMA). It was observed that cell cycle entry to early G1 was induced by either reagent acting alone, but both reagents were required to stimulate IL-2 production, IL-2R expression, and DNA synthesis. These effects of ionomycin and PMA were shown to be mediated by increased intracellular calcium ion concentration [Ca2+]i and PKC activation, respectively. Although, increased [Ca2+]i or PKC activation each led to cell cycle entry, the subsequent response of these preactivated cells to complete activation with both signals was different: Cells pretreated with PMA alone for up to 24 hr could progress further to DNA synthesis after the addition of ionomycin. In contrast, cells activated with ionomycin alone, or those cultured without any stimulus, progressively lost the ability to show DNA synthesis after complete activation. The failure to progress to DNA synthesis in these two cases was, however, differentially regulated by the ability of these cells to produce IL-2 and to express IL-2R. Ionomycin-pretreated cells retained the ability to produce IL-2 but showed about 70% reduction in the numbers of IL-2R; whereas cells cultured without any stimulus lost the ability to produce IL-2 after subsequent complete activation, but showed lesser reduction in IL-2R expression.
Collapse
Affiliation(s)
- A Lagoo
- Department of Pathology and Laboratory Medicine, University of Texas, Medical School, Houston 77030
| | | | | |
Collapse
|
13
|
Lagoo A, Tseng CK, Sell S. Molecular signals in B cell activation. II. IL-2-mediated signals are required in late G1 for transition to S phase after ionomycin and PMA treatment. Cell Immunol 1990; 127:497-505. [PMID: 2328536 DOI: 10.1016/0008-8749(90)90149-l] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We report that sustained increase of intracellular calcium ion concentration and protein kinase C (PKC) activation maintained throughout the G1 phase of cell cycle do not provide sufficient signals to cause S-phase entry in rabbit B cells, and that additional signals transduced by IL-2 and IL-2 receptor interaction are essential for G1 to S transition. We have shown earlier that rabbit B cells can be activated to produce IL-2 and express functional IL-2 receptors after treatment with ionomycin and PMA. Herein we have compared the response of rabbit PBLs, which contain about 50% T cells, with those of purified B cells. After activation with ionomycin or PMA, comparable numbers of PBLs and B cells entered the cell cycle; but DNA synthesis by the PBL cultures was three to four times higher than that of cultures of purified B cells. Interestingly, IL-2 production by the PBL cultures was also three to four times higher than in B cell cultures, suggesting an involvement of IL-2 in inducing DNA synthesis in these cells. The hypothesis that IL-2, which is produced in early G1, acts in late G1 and is required for G1 to S transition in B cells was supported by the following observations: (i) IL-2 production by B cells was detected as early as 6 hr after activation and preceded DNA synthesis by at least 24 hr. (ii) B cell blasts in G1 (produced by treatment of resting B cells with ionomycin and PMA) showed DNA synthesis in response to IL-2, but showed very little DNA synthesis in response to restimulation with ionomycin and PMA. (iii) A polyclonal rabbit anti-human IL-2 antibody caused nearly complete inhibition of DNA synthesis by B cells activated by ionomycin and PMA. (iv) A PKC inhibitor, K252b, inhibited DNA synthesis in ionomycin and PMA-stimulated cells if added at the beginning of culture but was not inhibitory if added 16 hr later. We conclude that increased [Ca2+]i and PKC activation are not sufficient signals for G1 to S transition in B cells; entry into S is signaled by IL-2, and IL-2-mediated signal transduction probably does not involve increased [Ca2+]i or PKC activation.
Collapse
Affiliation(s)
- A Lagoo
- Department of Pathology and Laboratory Medicine, University of Texas, Medical School, Houston 77030
| | | | | |
Collapse
|