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Hao E, Friso E, Miotto G, Jori G, Soncin M, Fabris C, Sibrian-Vazquez M, Vicente MGH. Synthesis and biological investigations of tetrakis(p-carboranylthio-tetrafluorophenyl)chlorin (TPFC). Org Biomol Chem 2008; 6:3732-40. [DOI: 10.1039/b807836j] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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152
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Jiao L, Hao E, Vicente MGH, Smith KM. Improved Synthesis of Functionalized 2,2‘-Bipyrroles. J Org Chem 2007; 72:8119-22. [PMID: 17887702 DOI: 10.1021/jo701310k] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of 2,2'-bipyrroles has been efficiently synthesized using an improved synthetic approach based on Pd(0)-catalyzed homocoupling of various 2-iodopyrroles. This new synthetic approach takes place at room temperature and in the presence of water. Functional groups such as formyl, ester, and nitrile are able to survive these reaction conditions. Solvents are found to play an important role in this reaction.
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Hao E, Fabre B, Fronczek FR, Vicente MGH. Poly[di(2-thiophenyl)carborane]s: conducting polymers with high electrochemical and thermal resistance. Chem Commun (Camb) 2007:4387-9. [PMID: 17957295 DOI: 10.1039/b710375a] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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154
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Sibrian-Vazquez M, Hao E, Jensen TJ, Vicente MGH. Enhanced cellular uptake with a cobaltacarborane-porphyrin-HIV-1 Tat 48-60 conjugate. Bioconjug Chem 2006; 17:928-34. [PMID: 16848399 DOI: 10.1021/bc060047v] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of four porphyrin-cobaltacarborane conjugates have been synthesized, containing three or four cobaltabisdicarbollide anions linked by O(CH(2)CH(2)O)(2) groups to the porphyrin macrocycle and one of them containing a HIV-1 Tat 48-60 peptide sequence linked via a low molecular weight poly(ethylene glycol) (PEG) spacer. The cellular uptake, cytotoxicity, and preferential sites of intracellular localization of the conjugates were evaluated in human HEp2 cells. All conjugates are nontoxic in the dark at the concentrations studied. Upon exposure to low light dose (1 J cm(-)(2)) only the porphyrin-cobaltacarborane-HIV-1 Tat 48-60 conjugate showed 30% inhibition of cell proliferation at a concentration of 10 microM. The cellular uptake was dependent on the number of carborane cages and was significantly enhanced by the presence of the cell penetrating peptide sequence HIV-1 Tat 48-60. All conjugates preferentially localized in the cell lysosomes.
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Hao E, Fronczek FR, Vicente MGH. Carborane functionalized pyrroles and porphyrins via the Suzuki cross-coupling reaction. Chem Commun (Camb) 2006:4900-2. [PMID: 17136240 DOI: 10.1039/b611571c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new route to carboranylated pyrroles and porphyrins is reported which involves the Suzuki coupling of readily available bromo- and boronic acid-pyrroles and bromoporphyrins with functionalized carboranes; the X-ray structures of two targeted products are presented and discussed.
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Hao E, Fronczek FR, Vicente MGH. Synthesis of Oxacalixarene-Locked Bisporphyrins and Higher Oligomers. J Org Chem 2006; 71:1233-6. [PMID: 16438543 DOI: 10.1021/jo051964h] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The efficient one-step synthesis of oxacalixarene-bisporphyrins and higher oligomers from readily available starting materials is described. The X-ray structure of one oxacalix[4]arene-locked cofacial bisporphyrin, prepared in 91% yield, shows an 1,3-alternate conformation of the molecule with partial overlap of the two porphyrin rings. 1H NMR data supports a similar conformation in solution. The absorption and emission spectra of oxacalixarene-porphyrins are briefly discussed.
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Jiao L, Hao E, Fronczek FR, Vicente MGH, Smith KM. Benzoporphyrins via an olefin ring-closure metathesis methodology. Chem Commun (Camb) 2006:3900-2. [PMID: 17268664 DOI: 10.1039/b607711k] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new route to benzoporphyrins is reported in which readily available vicinal dibromoporphyrins are bis-allylated using the Suzuki reaction, cyclized by way of olefin metathesis and finally oxidized to give mono-, di-, or tri-benzoporphyrins.
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Hao E, Jensen TJ, Courtney BH, Vicente MGH. Synthesis and Cellular Studies of Porphyrin−Cobaltacarborane Conjugates. Bioconjug Chem 2005; 16:1495-502. [PMID: 16287247 DOI: 10.1021/bc0502098] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The total syntheses of five new porphyrin-cobaltacarborane conjugates (1-5) have been achieved in 88-98% yields in a single-step reaction between a nucleophilic meso-pyridyl-containing porphyrin and zwitterionic cobaltacarborane [3,3'-Co(8-C(4)H(8)O(2)-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))]. These unique zwitterionic compounds have one to four cobaltabisdicarbollide anions conjugated to the porphyrin macrocycle via (CH(2)CH(2)O)(2) chains. The X-ray structure of one of these conjugates (1) is presented and discussed. The cellular uptake, cytotoxicity, and subcellular localization of cobaltacarboraneporphyrins 1-5 were investigated in human HEp2 cells. The number and distribution of cobaltacarborane residues linked to the porphyrin macrocycle has a significant effect on the cellular uptake of the conjugates.
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Abstract
Two porphyrin-cobaltacarborane conjugates and were prepared in high yields via a nucleophilic ring-opening reaction of . These novel boron-rich and fluorescent compounds have potential application as boron delivery agents for the boron neutron capture therapy of tumors.
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Itkin-Ansari P, Marcora E, Geron I, Tyrberg B, Demeterco C, Hao E, Padilla C, Ratineau C, Leiter A, Lee JE, Levine F. NeuroD1 in the endocrine pancreas: Localization and dual function as an activator and repressor. Dev Dyn 2005; 233:946-53. [PMID: 15906379 DOI: 10.1002/dvdy.20443] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The basic helix-loop-helix transcription factor NeuroD1 regulates cell fate in the nervous system but previously has not been considered to function similarly in the endocrine pancreas due to its reported expression in all islet cell types in the newborn mouse. Because we found that NeuroD1 potently represses somatostatin expression in vitro, its pattern of expression was examined in both strains of mice in which lacZ has been introduced into the NeuroD1 locus by homologous recombination. Analysis of adult transgenic mice revealed that NeuroD1 is predominantly expressed in beta-cells and either absent or expressed below the limit of lacZ detection in mature alpha-, delta-, or PP cells. Consistent with a previous report, NeuroD1 colocalizes with glucagon as well as insulin in immature islets of the newborn mouse. However, no colocalization of NeuroD1with somatostatin was detected in the newborn. In vitro, ectopic expression of NeuroD1 in TRM-6/PDX-1, a human pancreatic delta-cell line, resulted in potent repression of somatostatin concomitant with induction of the beta-cell hormones insulin and islet amyloid polypeptide. Additionally, NeuroD1 induced expression of Nkx2.2, a transcription factor expressed in beta- but not delta-cells. Transfection studies using insulin and somatostatin promoters confirm the ability of NeuroD1 to act as both a transcriptional repressor and activator in the same cell, suggesting a more complex role for NeuroD1 in the establishment and/or maintenance of mature endocrine cells than has been recognized previously.
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161
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Wang G, Hao E, Jiao L, Yan L. Investigation of solvatochromism and aggregation behavior of C60(C4H10N+)I− in binary solvent mixtures. CHINESE SCIENCE BULLETIN-CHINESE 2003. [DOI: 10.1007/bf03183982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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162
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de la Tour D, Halvorsen T, Demeterco C, Tyrberg B, Itkin-Ansari P, Loy M, Yoo SJ, Hao E, Bossie S, Levine F. Beta-cell differentiation from a human pancreatic cell line in vitro and in vivo. Mol Endocrinol 2001; 15:476-83. [PMID: 11222748 DOI: 10.1210/mend.15.3.0604] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cell transplantation therapy for diabetes is limited by an inadequate supply of cells exhibiting glucose-responsive insulin secretion. To generate an unlimited supply of human beta-cells, inducibly transformed pancreatic beta-cell lines have been created by expression of dominant oncogenes. The cell lines grow indefinitely but lose differentiated function. Induction of beta-cell differentiation was achieved by stimulating the signaling pathways downstream of the transcription factor PDX-1, cell-cell contact, and the glucagon-like peptide (GLP-1) receptor. Synergistic activation of those pathways resulted in differentiation into functional beta-cells exhibiting glucose-responsive insulin secretion in vitro. Both oncogene-expressing and oncogene-deleted cells were transplanted into nude mice and found to exhibit glucose-responsive insulin secretion in vivo. The ability to grow unlimited quantities of human beta-cells is a major step toward developing a cell transplantation therapy for diabetes.
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MacLean PS, Vadlamudi S, Hao E, Barakat HA. Differential expression of cholesteryl ester transfer protein in the liver and plasma of fasted and fed transgenic mice. J Nutr Biochem 2000; 11:318-25. [PMID: 11002127 DOI: 10.1016/s0955-2863(00)00084-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Because cholesteryl ester transfer protein (CETP) is considered a potential target in the treatment of atherosclerosis, several reports have focused on the regulation of this enzyme, and there is evidence that insulin may be a regulatory factor. The present study examines the differential expression of the human CETP gene between physiologic conditions that are accompanied by low (fasted) and high (fed) insulin levels. CETP expression was examined in plasma and tissues of transgenic mice expressing the human CETP minigene after 12 hours of fasting (n = 20) or ad libitum feeding (n = 20) with normal mouse chow. Plasma cholesteryl ester transfer activity (CETA) was 20% higher in fed than in fasted mice, reflecting higher levels of CETP (P < 0.05). This observation was accompanied by higher liver mRNA in fed mice (100%, P < 0.05), as determined by ribonuclease protection assays, as well as by higher CETA (23%, P < 0.05) and CETP mass (29%, P < 0.05) in the particulate fraction of liver homogenates. These parameters of liver CETP expression correlated well with each other, as well as with plasma CETA. CETP in the liver particulate fraction was found as a doublet (approximately 70 and 65 kDa), which resolved to a single band (approximately 60 kDa) upon deglycosylation. No differences in CETP expression were observed in pooled adipose tissue samples from fed and fasted mice. Insulin and glucose were not related to any plasma or tissue parameter of CETP expression. In summary, the concerted, differential expression of CETP in the liver of fed and fasted transgenic mice appears to contribute to higher plasma CETP levels in fed mice, but the precise role of insulin and glucose in regulating CETP expression under fasted and fed conditions needs to be defined.
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Hao E, Sun Y, Yang B, Zhang X, Liu J, Shen J. Synthesis and Photophysical Properties of ZnS Colloidal Particles Doped with Silver. J Colloid Interface Sci 1998; 204:369-73. [PMID: 9698417 DOI: 10.1006/jcis.1998.5591] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The synthesis and photophysical characterization of ZnS:Ag colloid are reported. The presence of mercaptoacetic acid has an important effect not only on the formation of doped and undoped ZnS but also on the photophysical properties. ZnS colloid doped with silver shows a strong green emission upon ultraviolet excitation, the intensity of which was enhanced significantly compared with that of the undoped colloid. The green emission was ascribed to a transition from a donor level such as anion vacancy to the levels of the Ag impurities. Copyright 1998 Academic Press.
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Shapiro AM, Gallant H, Hao E, Wong J, Rajotte R, Yatscoff R, Kneteman N. Portal vein immunosuppressant levels and islet graft toxicity. Transplant Proc 1998; 30:641. [PMID: 9532212 DOI: 10.1016/s0041-1345(97)01441-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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166
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Shapiro AM, Hao E, Lakey JR, Finegood D, Rajotte RV, Kneteman NM. Diabetogenic synergism in canine islet autografts from cyclosporine and steroids in combination. Transplant Proc 1998; 30:527. [PMID: 9532162 DOI: 10.1016/s0041-1345(97)01390-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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167
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Shapiro AM, Hao E, Lakey JR, Elliott JF, Rajotte RV, Kneteman NM. Development of diagnostic markers for islet allograft rejection. Transplant Proc 1998; 30:647. [PMID: 9532216 DOI: 10.1016/s0041-1345(97)01445-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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168
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Hayslip CC, Hao E, Usala SJ. The cystic fibrosis transmembrane regulator gene is expressed in the human endocervix throughout the menstrual cycle. Fertil Steril 1997; 67:636-40. [PMID: 9093186 DOI: 10.1016/s0015-0282(97)81358-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To measure cystic fibrosis transmembrane regulator (CFTR) gene expression in cervical secretions during the menstrual cycle. DESIGN Prospective, descriptive clinical study. PATIENTS Thirteen healthy women with ovulatory menstrual cycles. INTERVENTIONS Endocervical cells and secretions were obtained by cytobrushings during the midfollicular, midcycle, and luteal phases. The cells were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) for CFTR and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene expression. MAIN OUTCOME MEASURES Detection of CFTR gene expression and a quantitative comparison of the levels of CFTR to GAPDH gene expression. RESULTS All endocervical samples exhibited some degree of CFTR gene expression throughout the menstrual cycle; however, the levels of expression were variable. Cystic fibrosis transmembrane regulator gene expression did not correlate with E2 or P levels. CONCLUSION The production of copious cervical secretions at the time of ovulation in part may be because of the transport of sodium and water across endocervical cell membranes as a result of E2-stimulated CFTR mRNA and protein. Although cervical mucus becomes thick and scant during the luteal phase, CFTR gene expression is present in these secretions.
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Shapiro AM, Hao E, Rajotte RV, Kneteman NM. High yield of rodent islets with intraductal collagenase and stationary digestion--a comparison with standard technique. Cell Transplant 1996. [PMID: 8951221 DOI: 10.1016/s0963-6897(96)00084-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Intraductal distention of the pancreas with collagenase followed by stationary warm incubation improves the recovery of islets of Langerhans in the rat, but controlled studies are needed for valid comparison with standard isolation methods. We have modified Gotoh's technique of stationary digestion for high-yield isolation in the rat (Stationary). The method is subjected herein to rigorous blinded comparison with the standard chopped tissue (Chopped) technique, based on Lacy et al., as performed in our laboratory for over 10 yr. Islet recovery was determined by a single observe 'blinded' to the method of isolation used, and only intact islets of diameter > or = 100 microns were included. Stationary gave 719 +/- 114 islets per pancreas (mean +/- SD, n = 21 isolations) vs. 487.5 +/- 69 for Chopped (n = 36 isolations), a 47.5% increment in yield (p < 0.0001). In vitro islet perifusion showed no statistical difference in stimulation index (SI) or stimulated area under the curve (SAUC) between the two methods, but Stationary showed a trend towards improved phase II insulin release. In vivo function was assessed by isogeneic transplantation of 2,000 islets beneath the renal capsule of streptozotocin diabetic recipients (65 mg/kg Sigma); Stationary recipients (n = 7) became normoglycemic (< or = 8 mmol/L) by 3.3 +/- 4.8 days vs. 1.6 +/- 1.5 days for Chopped recipients (p = 0.4 ns, mean +/- SEM). IVGTT performed at 1 mo posttransplant gave K-values for Stationary of 2.64 +/- 0.8 vs. 2.62 +/- 0.8 for Chopped (mean +/- SD, p = 0.9 ns, n = 6, unpaired t-test), which were not distinguishable from normal control rats (2.59 +/- 0.8) (p = 0.9 ns, n = 10). Graft function remained stable until graft bearing nephrectomy induced hyperglycemia uniformly within 1 day. Graft histology showed a healthy well-preserved structure on light microscopy, with well-granulated beta cells on EM. Economic costs of rat, collagenase, and Ficoll were 26% ($50.82) lower per recipient for Stationary. We conclude that modified stationary digestion significantly improves islet recovery with excellent in vitro and in vivo function, and is cost effective.
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Shapiro AM, Hao E, Rajotte RV, Kneteman NM. Impact of Lazaroid U74006F on ischemia and reperfusion injury of islets after transplantation in the rat. Transplant Proc 1996; 28:85-6. [PMID: 8644350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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171
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Shapiro AM, Hao E, Rajotte RV, Kneteman NM. Stationary digestion after intraductal collagenase improves islet recovery in the rat. Transplant Proc 1995; 27:3378. [PMID: 8540004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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172
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Hao E. Divergent dimerization properties of mutant beta 1 thyroid hormone receptors are associated with different dominant negative activities. Mol Endocrinol 1994. [DOI: 10.1210/me.8.7.841] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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173
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Hao E, Menke JB, Smith AM, Jones C, Geffner ME, Hershman JM, Wuerth JP, Samuels HH, Ways DK, Usala SJ. Divergent dimerization properties of mutant beta 1 thyroid hormone receptors are associated with different dominant negative activities. Mol Endocrinol 1994; 8:841-51. [PMID: 7984146 DOI: 10.1210/mend.8.7.7984146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Syndromes of resistance to thyroid hormones are caused by mutations in the T3-binding domain of the c-erbA beta thyroid hormone receptor gene. The S receptor (deletion of THR332) is a potent dominant negative protein cloned from a kindred with generalized resistance to thyroid hormones. The G-H receptor (ARG311HIS) has compromised dominant negative function and was found in both normal individuals and in a patient with severe pituitary resistance to thyroid hormones. We have investigated the mechanism responsible for the difference in receptor phenotypes by analyzing the binding of S and G-H receptors to thyroid hormone response elements with electrophoretic mobility shift analysis. Wild-type human c-erbA beta 1 (WT), S, and G-H receptors were synthesized in reticulocyte lysate, reacted with a thyroid hormone response element consisting of a direct repeat with 4 base pairs (DR+4; AGGTCA CAGG AGGTCA), and the products analyzed by gel shift. G-H receptor homodimerization was greatly impaired; G-H formed predominantly monomeric complex compared with monomeric and homodimeric WT complexes. The G-H receptor was able to form heterodimeric complexes with cellular thyroid hormone receptor auxiliary protein (TRAP) factors including the human retinoid X receptor-alpha. When TRAP was limiting, the levels of G-H heterodimeric complex were 2- to 3-fold reduced compared with WT receptor. In contrast to the WT and G-H receptors, the S receptor formed almost exclusively homodimeric complex with DR+4; the approximate ratio of S:WT:G-H homodimeric complexes at equivalent concentrations of receptors was 60:20:1. A measurable increase (1.2- to 2.6-fold) in heterodimeric complex formation was observed with the S receptor relative to WT when TRAP was at limiting concentration. As reported previously by others, thyroid hormone significantly reduced the WT homodimeric complex with DR+4. There was no effect on the S homodimeric complex. Finally, the WT, S, and G-H receptors formed different complexes with the element consisting of an inverted repeat with 5 base pairs (IR+5; AGGTCA ACAGT TGACCT) and the IR element (AGGTCA TGACCT), which were differently regulated by thyroid hormone. The S receptor bound as a homodimer with IR+5, whereas the WT receptor bound as a homodimer only with thyroid hormone. No homodimeric complex formed with IR+5 and the G-H receptor. Qualitatively similar results were observed with the IR element. We conclude that the ARG311HIS mutation severely perturbs the homodimerization and, to a much less degree, heterodimerization functions of the c-erbA beta 1 receptor. Furthermore, the THR332 deletion mutation augments homodimerization of the c-erbA beta 1 receptor. These results indicate that different mutations in the c-erbA beta 1 thyroid hormone receptor have divergently affected dimerization activities which seem to influence the level of dominant negative activity in man.
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Ways DK, Qin W, Garris TO, Chen J, Hao E, Cooper DR, Usala SJ, Parker PJ, Cook PP. Effects of chronic phorbol ester treatment on protein kinase C activity, content, and gene expression in the human monoblastoid U937 cell. CELL GROWTH & DIFFERENTIATION : THE MOLECULAR BIOLOGY JOURNAL OF THE AMERICAN ASSOCIATION FOR CANCER RESEARCH 1994; 5:161-9. [PMID: 8180129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Immediate and sustained signal transduction is involved in mediating phorbol ester-induced changes in growth and differentiation. Activation of protein kinase C (PKC) is the initial step in phorbol ester-induced signal transduction. By virtue of preferential down-regulation of individual isoforms and generation of proteolytically derived kinase activities, the signal transduced by sustained activation of this pathway may differ substantially from that generated initially upon application of the phorbol ester. To examine the effect of chronic phorbol ester-induced activation of this pathway, the relationship between PKC activity/content and AP-1 binding activity and gene expression was studied in the U937 cell. Phorbol ester-induced differentiation of the U937 cell into a monocyte/macrophage-like cell requires sustained activation of the PKC pathway. AP-1 binding activity was enhanced by 12-O-tetradecanoylphorbol-13-acetate (TPA) and in a temporally dependent manner, with conversion of a high to low mobility band shift occurring after a 12-h exposure to TPA. After a 72-h exposure, AP-1 binding activity was maximally increased by 1 nM TPA and remained elevated to a similar degree even after treatment with 600 nM TPA. Enhanced AP-1 binding activity was dependent upon continuous exposure to TPA and was not secondary to differentiation. A 72-h treatment with one nM TPA maximally increased expression of c-jun, krox-24, and jun-B mRNA transcripts. Exposure to higher TPA concentrations decreased the content of these transcripts. Maximal expression of collagenase and plasminogen activator receptor transcripts required exposure to much higher TPA concentrations (100 nM).(ABSTRACT TRUNCATED AT 250 WORDS)
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Ways DK, Qin W, Cook P, Parker PJ, Menke JB, Hao E, Smith AM, Jones C, Hershman JM, Geffner ME. Dominant and nondominant negative C-erbA beta 1 receptors associated with thyroid hormone resistance syndromes augment 12-O-tetradecanoyl-phorbol-13-acetate induction of the collagenase promoter and exhibit defective 3,5,3'-triiodothyronine-mediated repression. Mol Endocrinol 1993; 7:1112-20. [PMID: 8247013 DOI: 10.1210/mend.7.9.8247013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
C-erbA receptors and v-erbA have been shown to functionally interact with 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-inducible gene expression. These proteins enhance trans-activation by c-jun, and the c-erbA receptors in the presence of thyroid hormone repress TPA and c-jun induction of transcription. Also, v-erbA can abrogate T3-mediated repression. We have examined how dominant negative (S and CL) and nondominant negative (G-H) receptors cloned from various patients with thyroid hormone resistance syndromes affect expression of the collagenase promoter induced with TPA. The CL receptor (ARG315HIS mutation) has a 2-fold reduction in T3-binding affinity compared with human c-erbA beta 1 wild-type (WT) receptor, whereas the G-H receptor (ARG311HIS) and S receptor (deletion, THR codon 332) have T3-binding affinities reduced by 100-fold and greater than 100-fold, respectively. These mutant receptors were cotransfected with a collagenase promoter (-1200 to +63 base pairs) chloramphenicol acetyltransferase reporter gene (Col-CAT) into COS-7 cells. Levels of CAT reporter gene expression after transient transfection were determined in the presence or absence of 3-10 nM T3 and the presence or absence of 100 nM TPA. Unoccupied CL receptor and G-H and S receptors stimulated TPA-induced Col-CAT expression 1.5- to 9-fold. The CL receptor with thyroid hormone totally repressed TPA induction of the collagenase receptor. In the presence of thyroid hormone, the enhancing effects by S and G-H receptors on TPA-induced Col-CAT expression were unaffected and minimally diminished, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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