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Abstract
In vitro systems capable of reconstituting the process of mouse oogenesis are now being established to help develop further understanding of the mechanisms underlying oocyte/follicle development and differentiation. These systems could also help increase the production of useful livestock or genetically modified animals, and aid in identifying the causes of infertility in humans. Recently, we revealed, using an in vitro system for recapitulating oogenesis, that the activation of the estrogen signaling pathway induces abnormal follicle formation, that blocking estrogen-induced expression of anti-Müllerian hormone is crucial for normal follicle formation, and that the production of α-fetoprotein in fetal liver tissue is involved in normal in vivo follicle formation. In mouse fetuses, follicle formation is not carried out by factors within the ovaries but is instead orchestrated by distal endocrine factors. This review outlines findings from genetics, endocrinology, and in vitro studies regarding the factors that can affect the formation of primordial follicles in mammals.
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Feng L, Wang Y, Wang X, An S, Aizimuaji Z, Tao C, Zhang K, Cheng S, Wu J, Xiao T, Rong W. Integrated analysis of the rhesus monkey liver transcriptome during development and human primary HCC AFP-related gene expression. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 25:406-415. [PMID: 34484865 PMCID: PMC8403716 DOI: 10.1016/j.omtn.2021.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/16/2021] [Indexed: 01/10/2023]
Abstract
Embryonic development and tumorigenesis have a certain degree of similarity. Alpha-fetoprotein (AFP), a protein related to embryonic development, is a well-known biomarker for the diagnosis and prognosis of hepatocellular carcinoma (HCC). In this study, we analyzed the differences in gene expression profiles and molecular mechanisms in human HCC tissues from patients in AFPhigh (serum AFP level ≥ 25 ng/mL) and AFPlow (serum AFP level < 25 ng/mL) groups. The results indicated that AFPhigh HCC has more malignant biological characteristics. Single-sample gene set enrichment analysis (ssGSEA) showed significantly higher levels of genes expressed in dendritic cells, neutrophils, and natural killer cells in the AFPlow group than in the AFPhigh group. Then, we defined a rhesus monkey fetal liver developmental landscape and compared it to the HCC gene expression profile. The gene signatures of AFPhigh HCC tissues were similar to those of early embryonic liver tissues. In this study, we comprehensively analyzed the rhesus monkey liver transcriptome during development and human primary HCC AFP-related gene expression profiles and clarified the function of AFP in the occurrence and development of HCC from the perspective of developmental biology, which might provide a new perspective on the pathogenesis of HCC.
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Affiliation(s)
- Lin Feng
- State Key Laboratory of Molecular Oncology, Department of Etiology and Carcinogenesis, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Yaru Wang
- State Key Laboratory of Molecular Oncology, Department of Etiology and Carcinogenesis, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Department of Hepatobiliary Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Xijun Wang
- State Key Laboratory of Molecular Oncology, Department of Etiology and Carcinogenesis, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Songlin An
- Department of Hepatobiliary Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Zulihumaer Aizimuaji
- State Key Laboratory of Molecular Oncology, Department of Etiology and Carcinogenesis, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Changcheng Tao
- Department of Hepatobiliary Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Kai Zhang
- Department of Hepatobiliary Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Shujun Cheng
- State Key Laboratory of Molecular Oncology, Department of Etiology and Carcinogenesis, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Jianxiong Wu
- Department of Hepatobiliary Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Corresponding author: Dr. Jianxiong Wu, Department of Hepatobiliary Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
| | - Ting Xiao
- State Key Laboratory of Molecular Oncology, Department of Etiology and Carcinogenesis, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Corresponding author: Dr. Ting Xiao, State Key Laboratory of Molecular Oncology, Department of Etiology and Carcinogenesis, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
| | - Weiqi Rong
- Department of Hepatobiliary Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Corresponding author: Dr. Weiqi Rong, Department of Hepatobiliary Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
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Ooi SK, Jiang H, Kang Y, Allard P. Examining the Developmental Trajectory of an in Vitro Model of Mouse Primordial Germ Cells following Exposure to Environmentally Relevant Bisphenol A Levels. ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:97013. [PMID: 34585602 PMCID: PMC8480152 DOI: 10.1289/ehp8196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 08/27/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Animal-based studies indicate that bisphenol A (BPA) exposure is detrimental to reproductive health, but its impact on the earliest stages of germ cell development remains poorly defined. OBJECTIVES Using a murine in vitro model of early germ cell specification and differentiation, we sought to assess whether exposure to low levels of BPA prior to formation of primordial germ cells (PGCs) alters their differentiation trajectory and unique molecular program. METHODS We used an established method of in vitro differentiation of mouse embryonic stem cells (ESCs) into epiblast-like cells (EpiLCs) followed by PGC-like cells (PGCLCs), which together recapitulate defined stages of early germ cell development. Cellular consequences were determined using hemocytometer-based cell counting, fixation, and intracellular staining, followed by flow cytometry/fluorescence-activated cell sorting (FACS) of cells exposed to increasing concentrations (range: 1 nM-10 μM) of BPA. To interrogate and characterize gene expression differences resulting from BPA exposure, we also generated RNA-seq libraries from RNA extracted from FACS-purified PGCLCs and performed transcriptome analysis using bioinformatics-based approaches. RESULTS Exposure of EpiLCs to BPA resulted in higher numbers of cells that were associated with a higher proportion of cells in S-phase as well as a lower proportion undergoing apoptosis; this difference occurred in a concentration-dependent manner. Exposure also resulted in a greater fraction of EpiLCs showing signs of DNA damage. Remarkably, EpiLC exposure did not negatively affect PGC specification and resulted in a concentration-dependent effect on PGCLC proliferation in XX but not XY cells. PGCLC transcriptome analysis revealed an aberrant program with significant deregulation of X-linked genes and retrotransposon expression. Differential gene expression analysis also revealed the deregulation of genes associated with lipid metabolism as well as deregulated expression of genes associated with later stages of gametogenesis. CONCLUSIONS To the best of our knowledge our findings represent the first characterization of the consequences of early BPA exposure on a model of mammalian PGC development, highlighting altered cell behavior, altered underlying pathways, and altered molecular processes. https://doi.org/10.1289/EHP8196.
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Affiliation(s)
- Steen K.T. Ooi
- UCLA Institute for Society & Genetics, University of California, Los Angeles, Los Angeles, California, USA
| | - Hui Jiang
- UCLA Institute for Society & Genetics, University of California, Los Angeles, Los Angeles, California, USA
| | - Yanyuan Kang
- UCLA Institute for Society & Genetics, University of California, Los Angeles, Los Angeles, California, USA
| | - Patrick Allard
- UCLA Institute for Society & Genetics, University of California, Los Angeles, Los Angeles, California, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA
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Tanimoto R, Sekii K, Morohaku K, Li J, Pépin D, Obata Y. Blocking estrogen-induced AMH expression is crucial for normal follicle formation. Development 2021; 148:dev197459. [PMID: 33658225 PMCID: PMC7990856 DOI: 10.1242/dev.197459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 02/22/2021] [Indexed: 12/18/2022]
Abstract
In mammals, primordial follicles assembled in fetuses or during infancy constitute the oocyte resources for life. Exposure to 17beta-estradiol and phytogenic or endocrine-disrupting chemicals during pregnancy and/or the perinatal period leads to the failure of normal follicle formation. However, the mechanisms underlying estrogen-mediated abnormal follicle formation and physiological follicle formation in the presence of endogenous natural estrogen are not well understood. Here, we reveal that estrogen receptor 1, activated by estrogen, binds to the 5' region of the anti-Mullerian hormone (Amh) gene and upregulates its transcription before follicle formation in cultured mouse fetal ovaries. Ectopic expression of AMH protein was observed in pregranulosa cells of these explants. Furthermore, the addition of AMH to the culture medium inhibited normal follicle formation. Conversely, alpha-fetoprotein (AFP) produced in the fetal liver reportedly blocks estrogen action, although its role in follicle formation is unclear. We further demonstrated that the addition of AFP to the medium inhibited ectopic AMH expression via estrogen, leading to successful follicle formation in vitro Collectively, our in vitro experiments suggest that upon estrogen exposure, the integrity of follicle assembly in vivo is ensured by AFP.
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Affiliation(s)
- Ren Tanimoto
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Kiyono Sekii
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Kanako Morohaku
- Department of Agriculture and Life Sciences, Shinshu University 8304 Minami-Minowa-mura Kamiina-gun, Nagano 399-4598, Japan
| | - Jianzhen Li
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - David Pépin
- Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
- Pediatric Surgical Research Laboratories, Department of Surgery, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Yayoi Obata
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
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Moldogazieva NT, Ostroverkhova DS, Kuzmich NN, Kadochnikov VV, Terentiev AA, Porozov YB. Elucidating Binding Sites and Affinities of ERα Agonists and Antagonists to Human Alpha-Fetoprotein by In Silico Modeling and Point Mutagenesis. Int J Mol Sci 2020; 21:ijms21030893. [PMID: 32019136 PMCID: PMC7036865 DOI: 10.3390/ijms21030893] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/24/2020] [Accepted: 01/28/2020] [Indexed: 02/06/2023] Open
Abstract
Alpha-fetoprotein (AFP) is a major embryo- and tumor-associated protein capable of binding and transporting a variety of hydrophobic ligands, including estrogens. AFP has been shown to inhibit estrogen receptor (ER)-positive tumor growth, which can be attributed to its estrogen-binding ability. Despite AFP having long been investigated, its three-dimensional (3D) structure has not been experimentally resolved and molecular mechanisms underlying AFP–ligand interaction remains obscure. In our study, we constructed a homology-based 3D model of human AFP (HAFP) with the purpose of molecular docking of ERα ligands, three agonists (17β-estradiol, estrone and diethylstilbestrol), and three antagonists (tamoxifen, afimoxifene and endoxifen) into the obtained structure. Based on the ligand-docked scoring functions, we identified three putative estrogen- and antiestrogen-binding sites with different ligand binding affinities. Two high-affinity binding sites were located (i) in a tunnel formed within HAFP subdomains IB and IIA and (ii) on the opposite side of the molecule in a groove originating from a cavity formed between domains I and III, while (iii) the third low-affinity binding site was found at the bottom of the cavity. Here, 100 ns molecular dynamics (MD) simulation allowed us to study their geometries and showed that HAFP–estrogen interactions were caused by van der Waals forces, while both hydrophobic and electrostatic interactions were almost equally involved in HAFP–antiestrogen binding. Molecular mechanics/Generalized Born surface area (MM/GBSA) rescoring method exploited for estimation of binding free energies (ΔGbind) showed that antiestrogens have higher affinities to HAFP as compared to estrogens. We performed in silico point substitutions of amino acid residues to confirm their roles in HAFP–ligand interactions and showed that Thr132, Leu138, His170, Phe172, Ser217, Gln221, His266, His316, Lys453, and Asp478 residues, along with two disulfide bonds (Cys224–Cys270 and Cys269–Cys277), have key roles in both HAFP–estrogen and HAFP–antiestrogen binding. Data obtained in our study contribute to understanding mechanisms underlying protein–ligand interactions and anticancer therapy strategies based on ERα-binding ligands.
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Affiliation(s)
- Nurbubu T. Moldogazieva
- Laboratory of Bioinformatics, I.M. Sechenov First Moscow State Medical University (Sechenov University), 119991 Moscow, Russia; (D.S.O.); (N.N.K.); (Y.B.P.)
- Correspondence:
| | - Daria S. Ostroverkhova
- Laboratory of Bioinformatics, I.M. Sechenov First Moscow State Medical University (Sechenov University), 119991 Moscow, Russia; (D.S.O.); (N.N.K.); (Y.B.P.)
- Department of Bioengineering, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Nikolai N. Kuzmich
- Laboratory of Bioinformatics, I.M. Sechenov First Moscow State Medical University (Sechenov University), 119991 Moscow, Russia; (D.S.O.); (N.N.K.); (Y.B.P.)
- Department of Drug Safety, I.M. Smorodintsev Research Institute of Influenza, WHO National Influenza Centre of Russia, 197376 Saint Petersburg, Russia
| | - Vladimir V. Kadochnikov
- Department of Food Biotechnology and Engineering, Saint Petersburg National Research University of Information Technologies, Mechanics and Optics, 197101 Saint-Petersburg, Russia;
| | - Alexander A. Terentiev
- Deparment of Biochemistry and Molecular Biology, N.I. Pirogov Russian National Research Medical University, 117997 Moscow, Russia;
| | - Yuri B. Porozov
- Laboratory of Bioinformatics, I.M. Sechenov First Moscow State Medical University (Sechenov University), 119991 Moscow, Russia; (D.S.O.); (N.N.K.); (Y.B.P.)
- Department of Food Biotechnology and Engineering, Saint Petersburg National Research University of Information Technologies, Mechanics and Optics, 197101 Saint-Petersburg, Russia;
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Sakkiah S, Guo W, Pan B, Kusko R, Tong W, Hong H. Computational prediction models for assessing endocrine disrupting potential of chemicals. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2019; 36:192-218. [PMID: 30633647 DOI: 10.1080/10590501.2018.1537132] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Endocrine disrupting chemicals (EDCs) mimic natural hormones and disrupt endocrine function. Humans and wildlife are exposed to EDCs might alter endocrine functions through various mechanisms and lead to an adverse effects. Hence, EDCs identification is important to protect the ecosystem and to promote the public health. Leveraging in-vitro and in-vivo experiments to identify potential EDCs is time consuming and expensive. Hence, quantitative structure-activity relationship is applied to screen the potential EDCs. Here, we summarize the predictive models developed using various algorithms to forecast the binding activity of chemicals to the estrogen and androgen receptors, alpha-fetoprotein, and sex hormone binding globulin.
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Affiliation(s)
- Sugunadevi Sakkiah
- a Division of Bioinformatics and Biostatistics , National Center for Toxicological Research, U.S. Food and Drug Administration , Jefferson , Arkansas , USA
| | - Wenjing Guo
- a Division of Bioinformatics and Biostatistics , National Center for Toxicological Research, U.S. Food and Drug Administration , Jefferson , Arkansas , USA
| | - Bohu Pan
- a Division of Bioinformatics and Biostatistics , National Center for Toxicological Research, U.S. Food and Drug Administration , Jefferson , Arkansas , USA
| | - Rebecca Kusko
- b Immuneering Corporation , Cambridge , Massachusetts , USA
| | - Weida Tong
- a Division of Bioinformatics and Biostatistics , National Center for Toxicological Research, U.S. Food and Drug Administration , Jefferson , Arkansas , USA
| | - Huixiao Hong
- a Division of Bioinformatics and Biostatistics , National Center for Toxicological Research, U.S. Food and Drug Administration , Jefferson , Arkansas , USA
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De Mees C, Bakker J, Szpirer J, Szpirer C. Alpha-Fetoprotein: From a Diagnostic Biomarker to a Key Role in Female Fertility. Biomark Insights 2017. [DOI: 10.1177/117727190600100002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Alpha-fetoprotein (AFP) is a well-known diagnostic biomarker used in medicine to detect fetal developmental anomalies such as neural tube defects or Down's syndrome, or to follow up the development of tumors such as hepatocellular carcinomas. However, and despite the fact that the protein was discovered almost half a century ago, little was known about its physiological function. The study of Afp knock-out mice uncovered a surprising function of AFP: it is essential for female fertility and for expression of normal female behaviors, and this action is mediated through its estrogen binding capacity. AFP sequestrates estrogens and by so doing protects the female developing brain from deleterious (defeminizing/masculinizing) effects of these hormones.
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Affiliation(s)
- Christelle De Mees
- Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires, Rue Profs Jeener & Brachet, 12; B-6041 Gosselies (Charleroi), Belgium
| | - Julie Bakker
- University of Liège, Center for Cellular & Molecular Neurobiology, Avenue de l'Hopital 1, B36; B-4000 Liège, Belgium
| | - Josiane Szpirer
- Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires, Rue Profs Jeener & Brachet, 12; B-6041 Gosselies (Charleroi), Belgium
| | - Claude Szpirer
- Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires, Rue Profs Jeener & Brachet, 12; B-6041 Gosselies (Charleroi), Belgium
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Hong H, Shen J, Ng HW, Sakkiah S, Ye H, Ge W, Gong P, Xiao W, Tong W. A Rat α-Fetoprotein Binding Activity Prediction Model to Facilitate Assessment of the Endocrine Disruption Potential of Environmental Chemicals. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:372. [PMID: 27023588 PMCID: PMC4847034 DOI: 10.3390/ijerph13040372] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 03/10/2016] [Accepted: 03/22/2016] [Indexed: 11/21/2022]
Abstract
Endocrine disruptors such as polychlorinated biphenyls (PCBs), diethylstilbestrol (DES) and dichlorodiphenyltrichloroethane (DDT) are agents that interfere with the endocrine system and cause adverse health effects. Huge public health concern about endocrine disruptors has arisen. One of the mechanisms of endocrine disruption is through binding of endocrine disruptors with the hormone receptors in the target cells. Entrance of endocrine disruptors into target cells is the precondition of endocrine disruption. The binding capability of a chemical with proteins in the blood affects its entrance into the target cells and, thus, is very informative for the assessment of potential endocrine disruption of chemicals. α-fetoprotein is one of the major serum proteins that binds to a variety of chemicals such as estrogens. To better facilitate assessment of endocrine disruption of environmental chemicals, we developed a model for α-fetoprotein binding activity prediction using the novel pattern recognition method (Decision Forest) and the molecular descriptors calculated from two-dimensional structures by Mold² software. The predictive capability of the model has been evaluated through internal validation using 125 training chemicals (average balanced accuracy of 69%) and external validations using 22 chemicals (balanced accuracy of 71%). Prediction confidence analysis revealed the model performed much better at high prediction confidence. Our results indicate that the model is useful (when predictions are in high confidence) in endocrine disruption risk assessment of environmental chemicals though improvement by increasing number of training chemicals is needed.
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Affiliation(s)
- Huixiao Hong
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Jie Shen
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Hui Wen Ng
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Sugunadevi Sakkiah
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Hao Ye
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Weigong Ge
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Ping Gong
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA.
| | - Wenming Xiao
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Weida Tong
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
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Choi HY, Kim SW, Kim B, Lee HN, Kim SJ, Song M, Kim S, Kim J, Kim YB, Kim JH, Cho SG. Alpha-fetoprotein, identified as a novel marker for the antioxidant effect of placental extract, exhibits synergistic antioxidant activity in the presence of estradiol. PLoS One 2014; 9:e99421. [PMID: 24922551 PMCID: PMC4055621 DOI: 10.1371/journal.pone.0099421] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 05/14/2014] [Indexed: 11/19/2022] Open
Abstract
Placenta, as a reservoir of nutrients, has been widely used in medical and cosmetic materials. Here, we focused on the antioxidant properties of placental extract and attempted to isolate and identify the main antioxidant factors. Porcine placental extracts were prepared through homogenization or acid hydrolysis, and their antioxidant activity was investigated in the human keratinocyte HaCaT cell line. Treatment with homogenized placental extract (H-PE) increased the cell viability of H2O2-treated HaCaT cells more than two-fold. H-PE treatment suppressed H2O2-induced apoptotic and necrotic cell death and decreased intracellular ROS levels in H2O2-treated HaCaT cells. The antioxidant factors in H-PE were found to be thermo-unstable and were thus expected to include proteins. The candidate antioxidant proteins were fractionated with cation-exchange, anion-exchange, and size-exclusion chromatography, and the antioxidant properties of the chromatographic fractions were investigated. We obtained specific antioxidant fractions that suppressed ROS generation and ROS-induced DNA strand breaks. From silver staining and MALDI-TOF analyses, alpha-fetoprotein (AFP) precursor was identified as a main marker for the antioxidant effect of H-PE. Purified AFP or ectopically expressed AFP exhibited synergistic antioxidant activity in the presence of estradiol. Taken together, our data suggest that AFP, a serum glycoprotein produced at high levels during fetal development, is a novel marker protein for the antioxidant effect of the placenta that exhibits synergistic antioxidant activity in the presence of estradiol.
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Affiliation(s)
- Hye Yeon Choi
- Department of Animal Biotechnology, Animal Resources Research Center, and Incurable Disease Animal Model and Stem Cell Institute (IDASI), Konkuk University, Seoul, Republic of Korea
| | - Seung Woo Kim
- Department of Animal Biotechnology, Animal Resources Research Center, and Incurable Disease Animal Model and Stem Cell Institute (IDASI), Konkuk University, Seoul, Republic of Korea
| | - BongWoo Kim
- Department of Animal Biotechnology, Animal Resources Research Center, and Incurable Disease Animal Model and Stem Cell Institute (IDASI), Konkuk University, Seoul, Republic of Korea
| | - Hae Na Lee
- Department of Animal Biotechnology, Animal Resources Research Center, and Incurable Disease Animal Model and Stem Cell Institute (IDASI), Konkuk University, Seoul, Republic of Korea
| | - Su-Jeong Kim
- Department of Animal Biotechnology, Animal Resources Research Center, and Incurable Disease Animal Model and Stem Cell Institute (IDASI), Konkuk University, Seoul, Republic of Korea
| | - Minjung Song
- Department of Animal Biotechnology, Animal Resources Research Center, and Incurable Disease Animal Model and Stem Cell Institute (IDASI), Konkuk University, Seoul, Republic of Korea
| | - Sol Kim
- Department of Life Science, Sogang University, Seoul, Republic of Korea
| | - Jungho Kim
- Department of Life Science, Sogang University, Seoul, Republic of Korea
| | - Young Bong Kim
- Department of Animal Biotechnology, Animal Resources Research Center, and Incurable Disease Animal Model and Stem Cell Institute (IDASI), Konkuk University, Seoul, Republic of Korea
| | - Jin-Hoi Kim
- Department of Animal Biotechnology, Animal Resources Research Center, and Incurable Disease Animal Model and Stem Cell Institute (IDASI), Konkuk University, Seoul, Republic of Korea
| | - Ssang-Goo Cho
- Department of Animal Biotechnology, Animal Resources Research Center, and Incurable Disease Animal Model and Stem Cell Institute (IDASI), Konkuk University, Seoul, Republic of Korea
- * E-mail:
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Shen J, Zhang W, Fang H, Perkins R, Tong W, Hong H. Homology modeling, molecular docking, and molecular dynamics simulations elucidated α-fetoprotein binding modes. BMC Bioinformatics 2013; 14 Suppl 14:S6. [PMID: 24266910 PMCID: PMC3851483 DOI: 10.1186/1471-2105-14-s14-s6] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Background An important mechanism of endocrine activity is chemicals entering target cells via transport proteins and then interacting with hormone receptors such as the estrogen receptor (ER). α-Fetoprotein (AFP) is a major transport protein in rodent serum that can bind and sequester estrogens, thus preventing entry to the target cell and where they could otherwise induce ER-mediated endocrine activity. Recently, we reported rat AFP binding affinities for a large set of structurally diverse chemicals, including 53 binders and 72 non-binders. However, the lack of three-dimensional (3D) structures of rat AFP hinders further understanding of the structural dependence for binding. Therefore, a 3D structure of rat AFP was built using homology modeling in order to elucidate rat AFP-ligand binding modes through docking analyses and molecular dynamics (MD) simulations. Methods Homology modeling was first applied to build a 3D structure of rat AFP. Molecular docking and Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) scoring were then used to examine potential rat AFP ligand binding modes. MD simulations and free energy calculations were performed to refine models of binding modes. Results A rat AFP tertiary structure was first obtained using homology modeling and MD simulations. The rat AFP-ligand binding modes of 13 structurally diverse, representative binders were calculated using molecular docking, (MM-GBSA) ranking and MD simulations. The key residues for rat AFP-ligand binding were postulated through analyzing the binding modes. Conclusion The optimized 3D rat AFP structure and associated ligand binding modes shed light on rat AFP-ligand binding interactions that, in turn, provide a means to estimate binding affinity of unknown chemicals. Our results will assist in the evaluation of the endocrine disruption potential of chemicals.
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Abstract
Alpha-fetoprotein (AFP) is a major mammalian embryo-specific and tumor-associated protein that is also present in small quantities in adults at normal conditions. Discovery of the phenomenon of AFP biosynthesis in carcinogenesis by G. Abelev and Yu. Tatarinov 50 years ago, in 1963, provoked intensive studies of this protein. AFPs of some mammalian species were isolated, purified and physico-chemically and immunochemically characterized. Despite the significant success in study of AFP, its three-dimensional structure, mechanisms of receptor binding along with a structure of the receptor itself and, what is the most important, its biological role in embryo- and carcinogenesis remain still obscure. Due to difficulties linked with methodological limitations, research of AFP was to some extent extinguished by the 1990 s. However, over the last decade a growing number of investigations of AFP and its usage as a tumor-specific biomarker have been observed. This was caused by the use of new technologies, primarily, computer-based and genetic engineering approaches in studying of this very important oncodevelopmental protein. Our review summarizes efforts of different scientific groups throughout the world in studying AFP for 50 years with emphasis on detailed description of recent achievements in this field.
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Terentiev AA, Moldogazieva NT, Levtsova OV, Maximenko DM, Borozdenko DA, Shaitan KV. Modeling of three dimensional structure of human alpha-fetoprotein complexed with diethylstilbestrol: docking and molecular dynamics simulation study. J Bioinform Comput Biol 2012; 10:1241012. [PMID: 22809347 DOI: 10.1142/s0219720012410120] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It has been long experimentally demonstrated that human alpha-fetoprotein (HAFP) has an ability to bind immobilized estrogens with the most efficiency for synthetic estrogen analog - diethylstilbestrol (DES). However, the question remains why the human AFP (HAFP), unlike rodent AFP, cannot bind free estrogens. Moreover, despite the fact that AFP was first discovered more than 50 years ago and is presently recognized as a "golden standard" among onco-biomarkers, its three-dimensional (3D) structure has not been experimentally solved yet. In this work using MODELLER program, we generated 3D model of HAFP on the basis of homology with human serum albumin (HSA) and Vitamin D-binding protein (VTDB) with subsequent molecular docking of DES to the model structure and molecular dynamics (MD) simulation study of the complex obtained. The model constructed has U-shaped structure in which a cavity may be distinguished. In this cavity the putative estrogen-binding site is localized. Validation by RMSD calculation and with the use of PROCHECK program showed good quality of the model and stability of extended region of four alpha-helical structures that contains putative hormone-binding residues. Data extracted from MD simulation trajectory allow proposing two types of interactions between amino acid residues of HAFP and DES molecule: (1) hydrogen bonding with involvement of residues S445, R452, and E551; (2) hydrophobic interactions with participation of L138, M448, and M548 residues. A suggestion is made that immobilization of the hormone using a long spacer provides delivery of the estrogen molecule to the binding site and, thereby, facilitates interaction between HAFP and the hormone.
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Affiliation(s)
- Alexander A Terentiev
- Department of Biochemistry, Russian State Medical University, Moscow 117997, Russia.
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13
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Hong H, Branham WS, Dial SL, Moland CL, Fang H, Shen J, Perkins R, Sheehan D, Tong W. Rat α-Fetoprotein binding affinities of a large set of structurally diverse chemicals elucidated the relationships between structures and binding affinities. Chem Res Toxicol 2012; 25:2553-66. [PMID: 23013281 DOI: 10.1021/tx3003406] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Endocrine disrupting chemicals interfere with the endocrine system in animals, including humans, to exert adverse effects. One of the mechanisms of endocrine disruption is through the binding of receptors such as the estrogen receptor (ER) in target cells. The concentration of any chemical in serum is important for its entry into the target cells to bind the receptors. α-Fetoprotein (AFP) is a major transport protein in rodent serum that can bind with estrogens and thus change a chemical's availability for entrance into the target cell. Sequestration of an estrogen in the serum can alter the chemical's potential for disrupting estrogen receptor-mediated responses. To better understand endocrine disruption, we developed a competitive binding assay using rat amniotic fluid, which contains very high levels of AFP, and measured the binding to the rat AFP for 125 structurally diverse chemicals, most of which are known to bind ER. Fifty-three chemicals were able to bind the rat AFP in the assay, while 72 chemicals were determined to be nonbinders. Observations from closely examining the relationship between the binding data and structures of the tested chemicals are rationally explained in a manner consistent with proposed binding regions of rat AFP in the literature. The data reported here represent the largest data set of structurally diverse chemicals tested for rat AFP binding. The data assist in elucidating binding interactions and mechanisms between chemicals and rat AFP and, in turn, assist in the evaluation of the endocrine disrupting potential of chemicals.
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Affiliation(s)
- Huixiao Hong
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AK 72079, USA.
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14
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Dudich E, Dudich I, Semenkova L, Benevolensky S, Morozkina E, Marchenko A, Zatcepin S, Dudich D, Soboleva G, Khromikh L, Roslovtceva O, Tatulov E. Engineering of the Saccharomyces cerevisiae yeast strain with multiple chromosome-integrated genes of human alpha-fetoprotein and its high-yield secretory production, purification, structural and functional characterization. Protein Expr Purif 2012; 84:94-107. [PMID: 22561245 DOI: 10.1016/j.pep.2012.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 04/11/2012] [Accepted: 04/14/2012] [Indexed: 11/20/2022]
Abstract
Alpha-fetoprotein (AFP) is a biological drug candidate of high medicinal potential in the treatment of autoimmune diseases, cancer, and regenerative medicine. Large-scale production of recombinant human alpha-fetoprotein (rhAFP) is desirable for structural and functional studies and applied research. In this study we cloned and expressed in the secreted form wild-type glycosylated human rhAFP and non-glycosylated mutant rhAFP(0) (N233S) in the yeast strain Saccharomyces cerevisiae with multiple chromosome-integrated synthetic human AFP genes. RhAFP and rhAFP(0) were successfully produced and purified from the culture liquids active naturally folded proteins. Elimination of the glycosylation by mutation reduced rhAFP(0) secretion about threefold as compared to the wild-type protein showing critical role of the N-linked glycan for heterologous protein folding and secretion. Structural similarity of rhAFP and rhAFP(0) with natural embryonic eAFP was confirmed by circular dichroism technique. Functional tests demonstrated similar type of tumor suppressive and immunosuppressive activity for both recombinant species rhAFP and rhAFP(0) as compared to natural eAFP. It was documented that both types of biological activities attributed to rhAFP and rhAFP(0) are due to the fast induction of apoptosis in tumor cells and mitogen-activated lymphocytes. Despite the fact that rhAFP and rhAFP(0) demonstrated slightly less effective tumor suppressive activity as compared to eAFP but rhAFP(0) had produced statistically notable increase in its ability to induce inhibition of in vitro lymphocyte proliferation as compared to the glycosylated rhAFP and eAFP. We conclude that N-linked glycosylation of rhAFP is required for efficient folding and secretion. However the presence of N-linked sugar moiety was shown to be unimportant for tumor suppressive activity but was critically important for its immunoregulative activity which demonstrates that different molecular mechanisms are involved in these two types of biological functional activities attributed to AFP.
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Affiliation(s)
- Elena Dudich
- Institute of Immunological Engineering, Lyubuchany, Moscow Region, Chekhov District 142380, Russia.
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15
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Abstract
Gonadal steroids that establish sexually dimorphic characteristics of brain morphology and physiology act at a particular stage of ontogeny. Testosterone secreted by the testes during late gestational and neonatal periods causes significant brain sexual dimorphism in the rat. This results in both sex-specific behaviour and endocrinology in adults. Sexual differentiation may be due to neurogenesis, migration or survival. Each mechanism appears to be uniquely regulated in a site-specific manner. Thus, the volume of an aggregate of neurones in the rat medial preoptic area (POA), termed the sexually dimorphic nucleus of the POA (SDN-POA), is larger in males than in females. The anteroventral periventricular nucleus (AVPV) is packed with neurones containing oestrogen receptor (ER)beta in female rats but, in males, ERbeta-positive neurones scatter into the more lateral portion of the POA. POA neurones are born up to embryonic days 16-17 and not after parturition. Therefore, neurogenesis is unlikely to contribute to the larger SDN-POA in males. DNA microarray analysis for oestrogen-responsive genes and western blotting demonstrated site-specific regulation of apoptosis- and migration-related genes in the SDN-POA and AVPV.
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Affiliation(s)
- Y Sakuma
- Department of Physiology, Nippon Medical School, Tokyo, Japan.
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16
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Zaretsky JZ, Wreschner DH. Protein multifunctionality: principles and mechanisms. TRANSLATIONAL ONCOGENOMICS 2008; 3:99-136. [PMID: 21566747 PMCID: PMC3022353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In the review, the nature of protein multifunctionality is analyzed. In the first part of the review the principles of structural/functional organization of protein are discussed. In the second part, the main mechanisms involved in development of multiple functions on a single gene product(s) are analyzed. The last part represents a number of examples showing that multifunctionality is a basic feature of biologically active proteins.
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Affiliation(s)
- Joseph Z Zaretsky
- Department Cell Research and Immunology, George Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv, Haim Levanon St., 69978 Tel-Aviv, Israel
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17
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De Mees C, Bakker J, Szpirer J, Szpirer C. Alpha-fetoprotein: from a diagnostic biomarker to a key role in female fertility. Biomark Insights 2007; 1:82-5. [PMID: 19690639 PMCID: PMC2716789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Alpha-fetoprotein (AFP) is a well-known diagnostic biomarker used in medicine to detect fetal developmental anomalies such as neural tube defects or Down's syndrome, or to follow up the development of tumors such as hepatocellular carcinomas. However, and despite the fact that the protein was discovered almost half a century ago, little was known about its physiological function. The study of Afp knock-out mice uncovered a surprising function of AFP: it is essential for female fertility and for expression of normal female behaviors, and this action is mediated through its estrogen binding capacity. AFP sequestrates estrogens and by so doing protects the female developing brain from deleterious (defeminizing/masculinizing) effects of these hormones.
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Affiliation(s)
- Christelle De Mees
- Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires, Rue Profs Jeener & Brachet, 12; B-6041 Gosselies (Charleroi), Belgium,Correspondence: De Mees Christelle, Université Libre de Bruxelles, institut de Biologie et de Médecine Moléculaires Rue Profs Jeener & Brachet, 12; B-6041 Gosselies (Charleroi), Belgium. Tel: +3226509703; e-mail:
| | - Julie Bakker
- University of Liège, Center for Cellular & Molecular Neurobiology, Avenue de l’Hopital 1, B36; B-4000 Liège, Belgium
| | - Josiane Szpirer
- Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires, Rue Profs Jeener & Brachet, 12; B-6041 Gosselies (Charleroi), Belgium
| | - Claude Szpirer
- Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires, Rue Profs Jeener & Brachet, 12; B-6041 Gosselies (Charleroi), Belgium
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18
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Terentiev AA, Moldogazieva NT. Structural and functional mapping of alpha-fetoprotein. BIOCHEMISTRY (MOSCOW) 2006; 71:120-32. [PMID: 16489915 DOI: 10.1134/s0006297906020027] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Alpha-fetoprotein (AFP) is a major mammalian oncofetal protein, which is also present in small quantities in adults. It is a member of the albuminoid gene superfamily, which consists of AFP, serum albumin, vitamin D binding protein, and alpha-albumin (afamin). Although physicochemical and immunological properties of AFP have been well-studied, its biological role in embryo- and carcinogenesis and in adult organisms as well as mechanisms underlying its functioning remain unclear. During the recent decades, the biological role of AFP has been evaluated by identification of its functionally important sites. Comparison of primary structure of AFP and some physiologically active proteins revealed similarity of some polypeptide regions. This has been used for prediction of AFP functions (i.e., its multifunctionality). Localization of functionally important sites followed by determination of their amino acid composition and type of biological activity has provided valuable information for structural-functional mapping of AFP. Some peptide fragments of AFP have been synthesized and tested for biological activity. This review summarizes data on structural-functional interrelationships. We also describe functionally important AFP sites found by various groups during the last decade of structural-functional mapping of AFP with experimentally confirmed and putative biologically active sites.
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Affiliation(s)
- A A Terentiev
- Russian State Medical University, 117997 Moscow, Russia.
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19
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De Mees C, Laes JF, Bakker J, Smitz J, Hennuy B, Van Vooren P, Gabant P, Szpirer J, Szpirer C. Alpha-fetoprotein controls female fertility and prenatal development of the gonadotropin-releasing hormone pathway through an antiestrogenic action. Mol Cell Biol 2006; 26:2012-8. [PMID: 16479017 PMCID: PMC1430253 DOI: 10.1128/mcb.26.5.2012-2018.2006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It has been shown previously that female mice homozygous for an alpha-fetoprotein (AFP) null allele are sterile as a result of anovulation, probably due to a defect in the hypothalamic-pituitary axis. Here we show that these female mice exhibit specific anomalies in the expression of numerous genes in the pituitary, including genes involved in the gonadotropin-releasing hormone pathway, which are underexpressed. In the hypothalamus, the gonadotropin-releasing hormone gene, Gnrh1, was also found to be down-regulated. However, pituitary gene expression could be normalized and fertility could be rescued by blocking prenatal estrogen synthesis using an aromatase inhibitor. These results show that AFP protects the developing female brain from the adverse effects of prenatal estrogen exposure and clarify a long-running debate on the role of this fetal protein in brain sexual differentiation.
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Affiliation(s)
- Christelle De Mees
- Université Libre de Bruxelles, IBMM, Laboratoire de Biologie du Développement, Rue Pr. Jeener & Brachet 12, B-6041 Gosselies (Charleroi), Belgium.
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20
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Mizejewski GJ. Biological roles of alpha-fetoprotein during pregnancy and perinatal development. Exp Biol Med (Maywood) 2004; 229:439-63. [PMID: 15169963 DOI: 10.1177/153537020422900602] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The use of alpha-fetoprotein (AFP) as a serum marker in cancer actually predates its employment in the detection of congenital defects; however, the latter use of AFP as a fetal defect marker has propelled its clinical utilization. Although the serum-marker capacity of AFP has long been exploited, less is known of the biological activities of this oncofetal protein during fetal and perinatal development. In the present review, the biological activities of AFP are discussed in light of this glycoprotein's presence in various biological fluid compartments: embryonic and fetal tissues, serum, urine, and reproductive fluids. After a review of the histochemical detection of AFP in various cells and tissues during development, AFP concentrations within various biological fluids were discussed in the context of gestational age and anatomic location. Discussion follows concerning the relationships and roles of AFP in developmental events such as erthyropoiesis, histogenesis/organogenesis, and ligand binding and in developmental disorders such as hypothyroidism, folate deficiencies, and acquired immunodeficiency disorder (AIDS). Based on its association with so many types of birth defects, malformations, and congenital anomalies, AFP can be viewed as a molecular "troubleshooter" until signal transduction pathways are established during pregnancy and prenatal development. The review concludes with a discussion of the place of AFP in the rapidly expanding field of proteomics.
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Affiliation(s)
- Gerald J Mizejewski
- Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, New York 12201, USA.
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21
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Teeguarden JG, Barton HA. Computational modeling of serum-binding proteins and clearance in extrapolations across life stages and species for endocrine active compounds. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2004; 24:751-70. [PMID: 15209943 DOI: 10.1111/j.0272-4332.2004.00473.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
One measure of the potency of compounds that lead to the effects through ligand-dependent gene transcription is the relative affinity for the critical receptor. Endocrine active compounds that are presumed to act principally through binding to the estrogen receptor (e.g., estradiol, genistein, bisphenol A, and octylphenol) comprise one class of such compounds. For making simple comparisons, receptor-binding affinity has been equated to in vivo potency, which consequently defines the dose-response characteristics for the compound. Direct extrapolation of in vitro estimated affinities to the corresponding in vivo system and to specific species or life stages (e.g., neonatal, pregnancy) can be misleading. Accurate comparison of the potency of endocrine active compounds requires characterization of biochemical and pharmacokinetic factors that affect their free concentration. Quantitative in vitro and in vivo models were developed for integrating pharmacokinetics factors (e.g., serum protein and receptor-binding affinities, clearance) that affect potency. Data for parameterizing these models for several estrogenic compounds were evaluated and the models exercised. While simulations of adult human or rat sera were generally successful, difficulties in describing early life stages were identified. Exogenous compounds were predicted to be largely ineffective at competing estradiol off serum-binding proteins, suggesting this was unlikely to be physiologically significant. Discrepancies were identified between relative potencies based upon modeling in vitro receptor-binding activity versus in vivo activity in the presence of clearance and serum-binding proteins. The examples illustrate the utility of this approach for integrating available experimental data from in vitro and in vivo studies to estimate the relative potency of these compounds.
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Dauphinée MJ, Mizejewski GJ. Human alpha-fetoprotein contains potential heterodimerization motifs capable of interaction with nuclear receptors and transcription/growth factors. Med Hypotheses 2002; 58:453-61. [PMID: 12323110 DOI: 10.1054/mehy.2001.1445] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Alpha-fetoprotein (AFP) serum levels in man have long been utilized as a tumor marker and as a birth defect screening agent in the clinical laboratory. Although the physiological role of AFP has remained obscure, the stereotypic carrier/transport function of a fetal counterpart to albumin has been attributed to this oncofetal protein. However, reports from a multitude of investigators in the last decade have provided a rationale to reconsider and extend the biological role of AFP to include cell growth modulation during development. Previously, a leucine zipper-like (heptad) motif, which mimicked that found in the steroid/thyroid receptor superfamily, was postulated for portions of the third domain of AFP. The present report proposes the presence of additional potential heterodimerization sites for the nuclear receptor superfamily members and other growth factors in the second and third domains of human AFP.
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Affiliation(s)
- M J Dauphinée
- Rumbaugh-Goodwin Institute of Cancer Research, Plantation, Florida 33313, USA.
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23
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Permyakov SE, Oberg KA, Cherskaya AM, Shavlovsky MM, Permyakov EA, Uversky VN. Human alpha-fetoprotein as a Zn(2+)-binding protein. Tight cation binding is not accompanied by global changes in protein structure and stability. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1586:1-10. [PMID: 11781144 DOI: 10.1016/s0925-4439(01)00079-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The binding of zinc to human alpha-fetoprotein (AFP) isolated from human umbilical cord serum was studied by fluorimetric Zn(2+)-titration. We found that the total number of strong binding sites for zinc on this protein was 5: AFP has one very strong (dissociation constant, K(d)<10(-8) M) and at least four lower affinity zinc binding sites (K(d)<10(-5) M). Fourier transform infrared (FTIR) analysis revealed that aspartate and histidine residues could be involved in the strong coordination of zinc. Intriguingly, binding of zinc to the protein does not induce structural changes that can be detected by circular dichroism, FTIR, intrinsic fluorescence or (1,1')-bi-(4-anilino)naphthalene-5,5'-disulfonic acid (bis-ANS) binding. Finally, scanning microcalorimetry measurements showed that stability of the protein is also unaffected by zinc binding in spite of the strength of the coordination. Such strong interactions without major structural consequences are highly unusual, and AFP may therefore be the first characterized representative of a new class of ligand-binding proteins.
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Affiliation(s)
- Serge E Permyakov
- Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
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Mizejewski GJ. Alpha-fetoprotein structure and function: relevance to isoforms, epitopes, and conformational variants. Exp Biol Med (Maywood) 2001; 226:377-408. [PMID: 11393167 DOI: 10.1177/153537020122600503] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Mammalian alpha-fetoprotein (AFP) is classified as a member of the albuminoid gene superfamily consisting of albumin, AFP, vitamin D (Gc) protein, and alpha-albumin. Molecular variants of AFP have long been reported in the biomedical literature. Early studies identified isoelectric pH isoforms and lectin-binding variants of AFP, which differed in their physicochemical properties, but not in amino acid composition. Genetic variants of AFP, differing in mRNA kilobase length, were later extensively described in rodent models during fetal/perinatal stages, carcinogenesis, and organ regeneration. With the advent of monoclonal antibodies in the early 1980s, multiple antigenic epitopes on native AFP were detected and categorized, culminating in the identification of six to seven major epitopes. During this period, various AFP-binding proteins and receptors were reported to inhibit certain AFP immunoreactions. Concomittantly, human and rodent AFP were cloned and the amino acid sequences of the translated proteins were divulged. Once the amino acid composition of the AFP molecule was known, enzymatic fragments could be identified and synthetic peptide segments synthesized. Following discovery of the molten globule form in 1981, the existence of transitory, intermediate forms of AFP were acknowledged and their physiological significance was realized. In the present review, the various isoforms and variants of AFP are discussed in light of their potential biological relevance.
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Affiliation(s)
- G J Mizejewski
- Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Albany 12201, USA.
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25
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Gillespie JR, Uversky VN. Structure and function of alpha-fetoprotein: a biophysical overview. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1480:41-56. [PMID: 11004554 DOI: 10.1016/s0167-4838(00)00104-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
alpha-Fetoprotein (AFP) is a large serum glycoprotein belonging to the intriguing class of onco-developmental proteins. AFP has attracted considerable attention since it was shown that the change in its serum level during pregnancy is a hallmark of the development of numerous embryonic disorders, while the increase in its content in the plasma of adults correlates with the appearance of several pathological conditions. Over the past 30 years, some 11000 papers have been published concerning AFP, an average rate of over a publication a day since 1969. The majority of publications are about the application of the protein in diagnostics, or about other uses of AFP in biomedicine; though some of them describe the biochemical and functional properties of AFP, two aspects have been extensively reviewed. However, surprisingly little is currently known about structural properties of this protein as well as about the molecular mechanism of its function. The present review pursues the aim to describe the current state of the art in studies of structural properties and conformational stability of AFP. An attempt to establish the relationship between conformational transformations in AFP and its function is also made.
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Affiliation(s)
- J R Gillespie
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
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Butterstein GM, Mizejewski GJ. Alpha-fetoprotein inhibits frog metamorphosis: implications for protein motif conservation. Comp Biochem Physiol A Mol Integr Physiol 1999; 124:39-45. [PMID: 10605066 DOI: 10.1016/s1095-6433(99)00088-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Alpha-fetoprotein (AFP) is a tumor-associated fetal protein which has served as a marker for both oncogenic and ontogenetic growth. A growth regulatory segment on human AFP contains amino acid sequence identity and similarity with Rana and Xenopus albumin molecules. This study assessed the ability of both intact mammalian AFP and a derived peptide to influence thyroid induction of tail resorption during Rana catesbeiana metamorphosis. After AFP and other proteins/peptides were pre-incubated with triiodothyronine (T3) for 1 h, they were added to intact tadpoles in 300 ml of water. Human and/or mouse AFP, at a concentration of 70 ng/ml, completely inhibited T3-induced tail loss when measured over a 5 day period. In contrast, albumin and other proteins were without affect. A peptide (P149) with the sequence of human AFP residues # 447-480 also completely blocked the tail response at a concentration of 33 ng/ml, whereas a scrambled version of this peptide was without activity. The present peptide segment derived from mammalian AFP might represent a highly conserved serum protein motif in the vertebrate phyla since it is capable of influencing growth, differentiation and transformation phenomenon in amphibians.
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Affiliation(s)
- G M Butterstein
- Department of Biological Sciences, Union College, Schenectady, NY 12308-2311, USA.
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Uversky VN, Narizhneva NV, Ivanova TV, Kirkitadze MD. Ligand-free form of human alpha-fetoprotein: evidence for the molten globule state. FEBS Lett 1997; 410:280-4. [PMID: 9237645 DOI: 10.1016/s0014-5793(97)00606-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
By means of circular dichroism and fluorescence spectroscopy, viscometry and scanning microcalorimetry we have shown that the release of ligands from human alpha-fetoprotein (AFP) results in a considerable rearrangement of the protein molecule. Ligand-free form is practically as compact as the native molecule and has native-like content of secondary structure but no rigid tertiary structure. This means that the release of ligands transforms the AFP molecule into a molten globule state. Stripping the ligands from AFP is the irreversible process, i.e., native protein molecule cannot be reconstituted from the ligand-free form of AFP by adding back ligands. A possible functional role of such a structural transformation is discussed.
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Affiliation(s)
- V N Uversky
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation.
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28
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Gray WG, Biswas EE, Bashirelahi N, Biswas SB. A low-affinity estrogen-binding site in pregnant rat uteri: analysis and partial purification. Proc Natl Acad Sci U S A 1994; 91:11502-6. [PMID: 7526397 PMCID: PMC45259 DOI: 10.1073/pnas.91.24.11502] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We have identified a low-affinity (type II) estrogen-binding site (EBS) that is expressed at high levels during pregnancy in rat uteri. Although this activity was detectable in nonpregnant rat uteri, it was present in amounts (0.094 pmol/g of uteri) that were severalfold lower than the high-affinity type I estrogen receptor (0.57 pmol/g of uteri). During pregnancy, at 19-20 days of gestation, the low-affinity type II EBS became the major (> or = 88%) estrogen-binding site in rat uteri. The increase in the level of low-affinity EBS (7.9 pmol/g) in uteri was approximately 85-fold with an approximately 20-fold increase in the specific activity (0.39 pmol/mg) of this form, whereas the high-affinity form remained relatively unchanged. We report here a method of purification of type II EBS from pregnant rat uteri and present an analysis of its DNA and steroid-binding properties. Estradiol-binding studies and Scatchard analysis showed that the type II EBS had an apparent estradiol-binding affinity of > or = 24 nM. Gel filtration and SDS/PAGE analysis indicated that the type II EBS was a monomeric 73-kDa protein. The estradiol binding remained apparently uninhibited in the presence of a large excess of tamoxifen, nafoxidine, or dihydrotestosterone. Estradiol, diethylstilbestrol, and quercitin (a type II EBS-specific inhibitor) competed efficiently. The purified low-affinity EBS did not have sequence-specific DNA-binding activity with the estrogen-responsive element, which indicated that it differs in function from the type I estrogen receptor.
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Affiliation(s)
- W G Gray
- Department of Pediatrics, School of Medicine, University of Maryland, Baltimore 21201
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Mizejewski GJ. An apparent dimerization motif in the third domain of alpha-fetoprotein: molecular mimicry of the steroid/thyroid nuclear receptor superfamily. Bioessays 1993; 15:427-32. [PMID: 7689318 DOI: 10.1002/bies.950150610] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Alpha-fetoprotein (AFP) is a tumor-associated fetal marker, associated both with tumor growth and with birth defects. AFP, whose precise function is unknown, has been classified as belonging to a protein superfamily together with albumin and vitamin D-binding (Gc) protein. AFP has been shown to bind various ligands in vitro including fatty acids, estrogens, thyroid hormones and retinoic acids. The steroid/thyroid nuclear receptor superfamily of proteins has recently become a major focus of biomedical investigation regarding regulation of gene expression. These receptors are thought to bind to DNA-hormone response elements (HRE) that affect growth, development, differentiation, reproduction and homeostasis. The HREs are known to share DNA sequences with the various members of the nuclear receptor superfamily. In the present report, the possibility of a leucine-zipper dimerization (heptad) motif in the carboxy-terminal third domain of both rodent and human AFP is postulated. The presence of nine such hydrophobic repeats in the third domain of the AFP molecule mimics the heptad dimerization repeats found in the retinoic acid, thyroid, c-erbA and other members of the nuclear receptor superfamily. Computer analysis revealed that the most conservative matching occurred between AFP and the retinoic acid class of receptors. However, other superfamily members displayed 40-60% homology with 5 of 9 AFP heptads. These findings could provide a possible mechanism for explaining the growth-regulatory properties (both inhibition and enhancement) that have been ascribed to AFP in the last decade.
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Affiliation(s)
- G J Mizejewski
- Laboratory of Human Genetics, Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509
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