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Johns Hopkins Bloomberg School of Public HealthCAAT

CAAT Grants Program

Research Grants 2015-2016: Summaries

  • Patrick Allard, University of California, Los Angeles
    Large scale investigation of enviornmental effects on reproduction
     
  • Maria Teresa Cruz, University of Coimbra
    In Chemico, in silico and in vitro modeling to predict human respiratory allergens
     
  • Sabra Klein, Johns Hopkins University
    Differentiated human respiratory epithelial cell cultures as a surrogate system for assessing the effects of estrogenic compounds on pulmonary disease pathogenesis

Abstracts

Patrick Allard

Large scale investigation of enviornmental effects on reproduction

Approximately 100,000 chemicals are currently in use worldwide with little safety data available for the majority of these chemicals. This is especially problematic in the United States, where more than 60,000 chemicals were grand-fathered in via the 1976 Toxic Substances Control Act. The difficulty in assessing safety of chemicals not only arises from their large number but also from the complexity of biological effects they elicit over a large range of doses. Furthermore, some effects are inherently difficult to observe in traditional toxicity tests such as reproductive processes that unfold over many months in mammals as well as epigenetic effects that can span multiple generations. Here, we propose to directly address these issues by developing and adapting two tests in a genetic model system, the worm C. elegans. Specifically, we are taking advantage of the evolutionary conservation of reproductive pathways and of the vast number of genetic tools in C. elegans to detect the induction of chromosome errors and also of transgenerational effects following chemical exposure. These studies therefore aim at developing unique methods to interrogate our chemical environment for its effect on reproduction and health.

Maria Teresa Cruz

In chemico, in silico and in vitro modeling to predict human respiratory allergens

The prevalence of respiratory allergies has dramatically increased over the last decades due to environmental and occupational factors, being occupational asthma the most prevalent occupational lung disease in developed countries with high levels of morbidity. More than 300 substances have been shown to cause occupational asthma, and a large proportion of these are low molecular weight (LMW) organic compounds. There is currently no widely accepted animal or non-animal method able to identify potential LMW respiratory sensitizers for regulatory purposes, despite the risk to human health. In addition, there is significant social, scientific and economic pressure to replace animal testing where possible. Therefore, development of non-animal assays for identifying potential respiratory allergenic chemicals is highly warranted to protect public health and will be of uttermost importance for the pharmaceutical, chemical, cosmetic, pesticide, and food industries. In this context, and supported by our expertise in the development of predictive in vitro toxicity tests, we intend to develop an innovative platform to predict respiratory sensitization hazard. For that, in chemico measurements of respiratory allergens with model peptides will be performed to assess the reactivity of respiratory allergens. In addition, the adjuvanticity/irritancy and immunogenicity triggered by respiratory allergens will be assessed in cells representative of the respiratory system. Finally, we will design a mathematical framework, derived from the readouts described above for the identification and classification of respiratory sensitizers.

Epithelix Sarl has provided a line of credit to Dr. Cruz for these studies. Epithelix produces standardized in vitro human lung tissue. We offer our sincere appreciation to Epithelix for this contribution.

Sabra Klein

Differentiated human respiratory epithelial cell cultures as a surrogate system for assessing the effects of estrogenic compounds on pulmonary disease pathogenesis

Women of reproductive ages tend to suffer more pulmonary disease, including asthma, chronic obstructive pulmonary disease, and infectious diseases than men. We know little about the mechanisms mediating these sex differences because epidemiological and clinical data on sex differences in pulmonary disease rarely translate into studies of the molecular and cellular mechanisms of pulmonary disease. With CAAT funding, we have demonstrated that the antiviral properties of estrogen-based therapies differ depending on sex. We show that the sex of cell cultures determines the outcome of influenza A virus (IAV) infection as well as the impact of natural estrogens (estradiol [E2]) and xenoestrogens (bisphenol A [BPA]) on virus replication and antiviral protein production, with the antiviral effects of estrogenic compounds being greater is cultures from female than male donors. We now seek to identify the pathways mediating the effects of estrogens and endocrine disrupting chemicals on the outcome of IAV infection in primary human cells to provide a mechanistic basis for defining effects of these estrogenic compounds on IAV infection. Primary, differentiated, human nasal epithelial cell (hNEC) cultures from males and females will be maintained in steroid-free media containing no estrogen, E2, or BPA. We will investigate the direct and indirect effects of estrogenic compounds on the host cellular responses to IAV infection, specifically focusing on the NF-κB signaling pathway. These data will show that the effects of estrogens and estrogenic compounds on human respiratory epithelial cell function and responses to infection are different between the sexes at cellular and molecular levels.