Grantee Research Project Results
2011 Progress Report: Formative Center for the Evaluation of Environmental Impacts on Fetal Development
EPA Grant Number: R834594Center: Formative Center for the Evaluation of Environmental Impacts on Fetal Development
Center Director: Boekelheide, Kim
Title: Formative Center for the Evaluation of Environmental Impacts on Fetal Development
Investigators: Boekelheide, Kim , De Paepe, Monique E , Phipps, Maureen , Brown, Phil , Gruppuso, Phillip , Kostadinov, Stephan
Current Investigators: Boekelheide, Kim , De Paepe, Monique E , Thanos, Christopher , Phipps, Maureen , Brown, Phil , Gruppuso, Phillip
Institution: Brown University , Women & Infants Hospital of Rhode Island
EPA Project Officer: Hahn, Intaek
Project Period: February 15, 2010 through February 14, 2014
Project Period Covered by this Report: February 15, 2011 through February 14,2012
Project Amount: $1,189,575
RFA: Children's Environmental Health and Disease Prevention Research Centers: Formative Centers (with NIEHS) (2009) RFA Text | Recipients Lists
Research Category: Children's Health , Human Health
Objective:
The research focuses on identifying new biomarkers – measurable biological indicators that can be used to identify how exposure to common environmental pollutants during early development may cause disease and can help identify individuals who may be at increased risk for disease.
Progress Summary:
Project 1
The purpose of this project is to study the effects of arsenic on fetal liver development. We seek to understand the relationship between altered fetal liver development and the risk for metabolic syndrome in the offspring.
The role of the liver in metabolic regulation and insulin sensitivity is well established. The association between intrauterine growth retardation, fetal metabolic programming and metabolic syndrome in the offspring is also established, having been shown in recent years to involve epigenetic mechanisms. Our goal is to develop a model to test the hypothesis that, like alterations in the nutrient environment, fetal arsenic exposure induces epigenetic changes in fetal liver that predispose to metabolic syndrome in the adult. The proposal is based on published evidence that fetal arsenic exposure induces epigenetic changes in fetal liver. The proposal also derives from our extensive characterization of growth-regulating signaling mechanisms in the fetal rat and our identification of novel biomarkers for the fetal hepatocyte phenotype. We have shown that late term fetal hepatocytes, unlike adult rat hepatocytes, show mitogenindependent proliferation and are resistance to the anti-proliferative effects of rapamycin, an inhibitor of the nutrient-sensing mTOR pathway. The aforementioned biomarkers include a number of proteins involved in growth factor signaling, cell cycle control and translation control. We have also observed that rapamycininduced inhibition of mTOR modulates gene expression in a manner most consistent with epigenetic mechanisms.
During our first year, we have been focused on developing a model in which liver tissue is transplanted into nude rats at the renal subcapsular and subcutaneous sites. The pre-implant tissues have had the appearance of normal liver with no evidence of necrosis. However, transplanted tissue has consistently shown signs of hepatocyte necrosis at times ranging from 24 to 72 hr. Results indicated that the transplanted liver tissue was losing viability and, when viability is satisfactory, hepatocytes are not engrafting.
Based on the results of these studies, a change in strategy may be warranted. It appears that the transplanted liver tissue is losing viability and, when viability was satisfactory, hepatocytes did not appear to be engrafting. Possible factors include cell-mediated immunity (not abrogated in the nude rats we are using) or inadequate vascularization.
Project 2
The high incidence of prostate cancer is a serious concern amongst older men. Environmental exposures to estrogenic chemicals may play a large role in prostate cancer, and understanding the underlying mechanisms will inevitably lead to new treatments. Xenotransplantation is a useful technique allowing for proper vascularization and growth of various types of tissue. The use of human prostate tissue in this xenotransplant model makes this project novel and highly relevant. This project will provide new insight into the growth and development of the human prostate with and without estradiol treatment. It will also provide a new platform to investigate the epigenetic modifications that occur after exposure to different types of estrogenic compounds. These new discoveries will help to inform future studies and provide a better understanding of how endocrine disrupting chemical exposure during a critical window of development may affect the normal progression of prostate growth.
The goal of our project is to build a human-based platform to evaluate the developmental origins of prostate disease induced by endocrine disrupting chemicals and to gain insight into the underlying epigenetic mechanisms that control disease induction and progression. We intend to achieve our goal by 1) characterizing human fetal prostate xenograft development by histopathology, immunohistochemical staining, and gene expression, 2) identifying alterations in differentiation and carcinogenic effects of estradiol exposure of prostate xenotransplants, and 3) using a genome-wide approach to investigate epigenetic alterations induced by endocrine disruptive exposures during human prostate development.
During this first year, we have practiced the needed tissue procurement and xenotransplant procedures and optimized our immunohistochemical techniques. We have also started to perform and to characterize the prostate xenotransplanted tissue.
The tissue was obtained and transplanted into the renal subcapsular space of an immunodeficient rat host using a retroperitoneal surgical approach. So far we have completed three grafts. Preliminary data indicates that these transplanted tissues are viable at all the time-points examined so far (7, 14, and 30 days post-transplant). The transplanted prostates grow significantly and develop appropriate vascularization. With these samples, we have begun to characterize time-dependent changes in cellular properties related to growth and differentiation by performing histopathology and immunohistochemical staining at various time points after transplant. This characterization has been performed with both control and estradiol (E2) treated samples. We have optimized the immunohistochemical staining for a number of differentiation and characterization biomarkers. These biomarkers detect epithelial and stromal maturation, neuroendocrine cells, and hormone receptors. Also, the incidence of proliferation and apoptosis are assessed.
Project 3
This study investigates the effects of environmentally relevant arsenic exposures in utero on postglandular lung remodeling. Our purpose is the gain insight into the etiology of arsenic-induced respiratory disease and lung cancers, with the aim of elucidating molecular targets and biomarkers of inorganic arsenic exposure during fetal lung development. Furthermore, we hope our research will provide a framework for future studies investigating the effects of other environmental toxicants on developing human lungs.
We hypothesize that arsenic exposure of human fetal lung xenotransplants results in disrupted postglandular lung remodeling mediated by molecular and epigenetic alterations. The aims of our research are to develop a human fetal lung xenograft model of in utero arsenic exposure, to determine the effects of arsenic exposure on growth dynamics and gene expression in the developing human fetal lung, and to determine arsenic-induced epigenetic changes in the developing human lung.
Our work has focused on the establishment of the human lung xenograft model. From our initial studies, we conclude:
- Harvesting, implantation and retrieval of human lung xenografts is feasible.
- The development of human lung xenografts parallels that of human lungs in utero, providing an excellent experimental model to study the effects of arsenic and other antenatal environmental exposures on human lung development.
- Based on ease of implantation and subsequent retrieval, as well as the faithful replication of normal development in this location, the kidney subcapsular site is preferred over the subcutaneous site.
Future Activities:
Project 1
The significance of this project lies in its potential to develop a model system to study mechanisms for programming of human fetal liver, something that is not possible with available methodologies. Achieving this goal would permit our own planned studies on the effect of environmental toxicants on fetal liver development. In addition, we hope to succeed in establishing a well characterized model that can be used by other investigators.
If, with additional experiments, it still appears that the liver xenotransplants are not surviving, we will pursue three options in order to establish a model with which we can test our hypothesis. The first option will be to change the transplantation site to liver. This may allow for faster and more robust vascularization of the transplanted tissue. A second approach, aimed at alleviating a cellular immune response, will be to use a SCID mouse rather the nude rats employed for the present studies. While this approach may limit the volume of tissue that we will be able to transplant per animal, we expect that the amount of tissue would be sufficient for the proposed studies.
In addition to these two approaches, we have begun to explore the possibility of using an in vitro approach, liver slices. While its use would preclude in vivo manipulations, this model would still offer the opportunity to accomplish the aims of our study.
Project 2
We are quite pleased with our progress to date, and will continue to pursue our goals as described here. We also plan to initiate the planned high density arrays for characterizing DNA methylation status in the transplants.
Project 3
These pilot studies have demonstrated that human lung xenografts provide a reliable model of postglandular lung remodeling. We are now poised to start the arsenic exposure experiments and will study the effects of arsenic exposure on lung growth dynamics, gene expression and epigenetics.
Journal Articles: 8 Displayed | Download in RIS Format
Other center views: | All 13 publications | 8 publications in selected types | All 8 journal articles |
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Boekelheide K, Blumberg B, Chapin RE, Cote I, Graziano JH, Janesick A, Lane R, Lillycrop K, Myatt L, States JC, Thayer KA, Waalkes MP, Rogers JM. Predicting later-life outcomes of early-life exposures. Environmental Health Perspectives 2012;120(10):1353-1361. |
R834594 (Final) R834594C002 (Final) |
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De Paepe ME, Chu S, Hall S, Heger NE, Thanos C, Mao Q. The human fetal lung xenograft: validation as model of microvascular remodeling in the postglandular lung. Pediatric Pulmonology 2012;47(12):1192-1203. |
R834594 (2012) R834594 (Final) R834594C003 (Final) |
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De Paepe ME, Chu S, Heger N, Hall S, Mao Q. Resilience of the human fetal lung following stillbirth: potential relevance for pulmonary regenerative medicine. Experimental Lung Research 2012;38(1):43-54. |
R834594 (2012) R834594 (Final) R834594C003 (Final) |
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Heger NE, Hall SJ, Sandrof MA, McDonnell EV, Hensley JB, McDowell EN, Martin KA, Gaido KW, Johnson KJ, Boekelheide K. Human fetal testis xenografts are resistant to phthalate-induced endocrine disruption. Environmental Health Perspectives 2012;120(8):1137-1143. |
R834594 (Final) R834594C002 (Final) |
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Panikkar B, Smith N, Brown P. Reflexive research ethics in fetal tissue xenotransplantation research. Accountability in Research 2012;19(6):344-369. |
R834594 (2012) R834594 (Final) |
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Saffarini CM, McDonnell EV, Amin A, Spade DJ, Huse SM, Kostadinov S, Hall SJ, Boekelheide K. Maturation of the developing human fetal prostate in a rodent xenograft model. The Prostate 2013;73(16):1761-1775. |
R834594 (2012) R834594 (Final) R834594C002 (Final) |
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Spade DJ, Hall SJ, Saffarini CM, Huse SM, McDonnell EV, Boekelheide K. Differential response to abiraterone acetate and di-n-butyl phthalate in an androgen-sensitive human fetal testis xenograft bioassay. Toxicological Sciences 2014;138(1):148-160. |
R834594 (Final) R834594C002 (Final) |
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Thompson MR, Boekelheide K. Multiple environmental chemical exposures to lead, mercury and polychlorinated biphenyls among childbearing-aged women (NHANES 1999-2004): body burden and risk factors. Environmental Research 2013;121:23-30. |
R834594 (Final) |
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Supplemental Keywords:
in utero exposure, mammalian, metals, bisphenol A, developmental biology, perinatal programming, arsenic, endocrine disrupting chemicals, estradiol, bisphenol A (BPA)., Health, Scientific Discipline, ENVIRONMENTAL MANAGEMENT, Health Risk Assessment, Risk Assessments, Biology, Risk Assessment, biological pathways, children's health, fetal exposure, bioavailability, developmental effects, perinatal exposure, biochemical researchRelevant Websites:
http://biomed.brown.edu/CEH/ ExitProgress and Final Reports:
Original Abstract Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R834594C001 Liver and the Metabolic Syndrome
R834594C002 Prostate and Endocrine Disruption
R834594C003 Lung, Arsenic Exposure, and Tissue Remodeling
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.