Annual Report for Fiscal Year 2017

Biologically based dose-response modeling for the thyroid axis in the fetus and neonate

Study Scientist: Jeffrey Fisher

(1) Creation of biologically based dose-response models for the hypothalamic-pituitary-thyroid axis in the developing rat and human as a function of iodide status.

(2) Interfacing of the models with physiologically based pharmacokinetic or toxicokinetic models for thyroid active chemicals with predicted conditions, such as iodide status and chemical exposure, for which brain thyroid hormone homeostasis cannot be maintained in the fetus and neonate.

(3) Use of the models to evaluate the possible influence of population exposures to thyroid active chemicals on fetal and neonatal thyroid status as a function of iodide intake.

Relationship between liver epigenetic phenotype and susceptibility to nonalcoholic steatohepatitis-induced (NASH) hepatocarcinogenesis in mice

Study Scientist: Igor Pogribny

(1) Determination of the role of epigenetic dysregulation in the etiology and pathogenesis of dietary NASH-induced hepatocarcinogenesis in mice.

(2) Determination of whether interstrain-specific susceptibility of mice to NASH-induced hepatocarcinogenesis is associated with differences in individual hepatic epigenetic phenotypes.

(3) Determination of the role of epigenetic dysregulation in the etiology and pathogenesis of NASH-induced hepatocarcinogenesis in mice induced by tamoxifen administration.

(4) Determination of whether aberrant epigenetic markers can be used as targets for preventing NASH- induced hepatocarcinogenesis in mice.

Sex differences in drug-induced QT prolongation and torsade de pointes: Establishing an in vitro model for high throughput screening and risk assessment of torsadogenic drugs

Study Scientist: Li Pang

(1) Establishment of the in vitro model and positive control.

(2) Evaluation of model sensitivity and specificity and tests of the possibility of high-throughput screening and ranking of QT-prolonging drugs for the risk of torsade de pointes.

Mechanism of tumorigenic pyrrolizidine alkaloids and development of liquid chromatography-electrospray ionization/multistage mass spectrometry (LC-ESI/MS/MS) methodology for detection and quantification of pyrrolizidine alkaloids

Study Scientist: Peter Fu

(1) Validation of the proposed mechanism by which pyrrolizidine alkaloids induce tumors in rodents.

(2) Development of an LC-ES/MS/MS method for detecting and quantifying dehaloperoxidase-derived DNA adducts in rodents.

(3) Development of an LC-ES/MS/MS method for detecting and quantifying genotoxic pyrrolizidine alkaloids in herbal plants and herbal dietary supplements.

(4) Development of an LC-ES/MS/MS method for detecting and quantifying dehaloperoxidase-derived hemoglobin adducts in rodents.

Human biomonitoring for bisphenol A (BPA)

Study Scientist: Daniel Doerge

(1) Development and implementation of a sensitive and selective analytical methodology to measure BPA in human blood and urine.

(2) Integration of animal exposure data and human biomonitoring data into a PBPK model for BPA.

Evaluation of the effects of black cohosh on risedronate efficacy in perimenopausal rat model

Study Scientist: Amy Inselman

Determination of the effects of risedronate and black cohosh (alone or combined) on bone density, bone turnover, and bone histology in a postmenopausal rat model.

Development and evaluation of a novel in vitro epigenomic screening model system for the hazard identification of FDA-regulated products

Study Scientist: Igor Pogribny

(1) Determination of the dose-dependent, in vitro genetic and epigenetic effects of compounds FDA regulates.

(2) Characterization of the specific epigenetic changes induced in vitro by genotoxic and nongenotoxic compounds.

(3) Characterization of the specific genetic and epigenetic effects of compounds FDA regulates using an in vitro three-dimensional organotypic liver culture model system.

Developing methods for the analysis of brominated vegetable oils and derivatives

Study Scientist: Gonçalo Gamboa da Costa

Development of methods for analyzing the food additive, brominated vegetable oil, in rat feed and rat tissues.

Identification of mechanistic biomarkers of pyrrolizidine alkaloid (PA)-induced hepatocarcinogenesis

Study Scientist: William Tolleson

Use of high-throughput profiling approaches to identify microRNAs that regulate genes involved in PA carcinogenicity in hepatic cell systems and investigation of the functions of microRNAs by bioinformatics tools and in vitro functional assays. These results will identify microRNA species for use as biomarkers for PA-induced carcinogenicity, with added benefits derived from mechanistic knowledge of how these microRNAs might function in the biological effects of PAs. The discovery and characterization of microRNAs associated with the hepatocarcinogenic activity of PAs will benefit food safety and human health by providing simple tools for assessing exposure to foodborne toxins.

Assessment of gaseous anesthetics in the developing nonhuman primate

Study Scientist: John Talpos

(1) Determination of the dose-response effects of gaseous anesthetics nitrous oxide and isoflurane (individual or combined) on neuronal cell death in the developing nonhuman primate using magnetic resonance imaging (MRI) and positron emission tomography (MicroPET).

(2) Determination of the effects of dose and duration of gaseous anesthetics on nonhuman primate long-term behavior and pathology using MRI and MicroPET.

(3) Evaluation of antioxidants in the amelioration of toxicity associated with gaseous anesthetics.

Developmental neurotoxicity assessment of N-methyl-D-aspartate (NMDA) receptor antagonists in zebrafish

Study Scientist: Jyotshnabala Kanungo

(1) Study of wildtype zebrafish embryos exposed to NMDA receptor antagonists (MK-801, dextromethorphan, ketamine, and sevoflurane) to assess their effects on Rohon-Beard sensory neurons. The effects on the primary and secondary motor neurons and their axons are being assessed using hb9:GFP transgenic embryos. Postexposure washout experiments are being pursued to determine the effects of these drugs on the nervous system.

(2) Determination of estradiol-17β levels in control and treated embryos and quantification of changes in gene expression for the two CYP aromatases/estrogen synthases (brain aromatase cyp19a1b and gonadal aromatase cyp19a1a) using quantitative polymerase chain reaction (qPCR).

(3) Assessment of phenotype-based cell signaling mechanisms, such as MAPK (mitogen-activated protein kinases) and neuron development-specific gene expression.

(4) Examination of reversal of noted adverse effects of these compounds on neurons, particularly by treatment with acetyl L-carnitine.

Toxicity assessment of graphene sheets using primary striatal neurons

Study Scientist: Syed Ali

(1) Evaluation of the toxicity of graphene sheets using in vitro primary cultures of embryonic day 14 primary rat striatal neurons.

(2) Determination of pathways involved in graphene toxicity using embryonic day 14 primary rat striatal neurons.

Identification of protein biomarkers for neurotoxicity assessments using a high-throughput antibody microarray approach

Study Scientist: Qiang Gu

(1) Examination of proteomic changes at the expression and phosphorylation levels using five established in vivo models of neurotoxicity.

(2) Identification of common changes in protein expression and phosphorylation status in these animal model systems.

(3) Confirmation of the observed alterations in protein expression and phosphorylation status by independent methods.

(4) Application of the proteomic findings to a global ischemic animal model to verify the utility of protein biomarkers for use in neurotoxicity assessments.

Effects of developmental sevoflurane exposure and pretreatment with acetyl-L-carnitine on complex brain function in rats

Study Scientist: John Chelonis

(1) Examination of the effects of early developmental sevoflurane exposure on neurodegeneration and complex operant learning.

(2) Determination of whether pretreatment with acetyl-L-carnitine can attenuate impairments in these measures.

(3) Examination of the time course of acetyl-L-carnitine pretreatment on sevoflurane-induced neuroapoptosis.

Rat blood-brain-barrier-on-a-chip model to study traumatic brain injury

Study Scientist: Syed Ali

(1) Use of soft lithograph and microfabrication techniques to engineer a multilayered blood-brain-barrier-on-a-chip model that can be subjected to different magnitudes and durations of mechanical stress that mimic mild and repetitive traumatic brain injury.

(2) Characterization of the effects of traumatic brain injury on blood-brain-barrier integrity using the chip model.

High-throughput neurotoxicity screening of metallic nanoparticles: In vitro and in vivo imaging

Study Scientist: Syed Imam

Assessment of the utility of high-throughput neurotoxicity screening of metallic nanoparticles for detecting neurochemical and neurophysiological alterations in vitro for use in developing reference standards for metallic nanoparticles. Once developed and validated, these techniques can be optimized for analyzing other FDA-regulated nanomaterials.

Proteomic assessment of the cytotoxic effects of nanoparticles on the blood-brain barrier

Study Scientist: Qiang Gu

Use of proteomic approaches to quantify alterations in expression and phosphorylation of proteins involved in apoptosis, inflammation, oxidative stress, and tumorigenesis signaling pathways in blood-brain barrier cells following exposure to nanoparticles. The long-term goal is to establish proteomic parameters for toxicity of nanoparticles.

Complement assays for the detection of immune-sensitizing activity of nanomaterials

Study Scientist: Julian Leakey

(1) Establishment of two complement assays for routine evaluation of immune-sensitizing activity of nanomaterials.
(2) Validation of the assays using nanoparticles with known immunoreactivity.
(3) Determination of the immune-sensitizing activity of novel nanomaterials.

Physiologically based pharmacokinetic (PBPK) modeling of nanomedicine: Building clinically relevant standards for FDA-regulated nanoparticulate drug products

Study Scientist: Julian Leakey

(1) Determination of in vivo liposomal doxorubicin release kinetics in individual tissues and the blood stream using PBPK modeling.
(2) Establishment of quantitative physicochemical property (liposomal size and content of ammonium sulfate) biodistribution relationships of liposomal doxorubicin products by PBPK modeling.
(3) Extrapolation of the PBPK model to rats and humans. A whole-body PBPK model is being developed to describe and simulate the biodistribution of liposomal vesicles and doxorubicin.

Assessment of size- and shape-dependent toxicity of silver (Ag) nanoparticles as measured by changes in the permeability at the gastrointestinal surface

Study Scientist: Sangeeta Khare

(1) Determination of the genotoxicity of graphene and derivatives in standard regulatory test battery assays.
(2) Determination of whether any mutagenicity in mouse lymphoma cells is due to loss of heterozygosity in chromosome 11.
(3) Investigation of whether genotoxic and mutagenic responses are mediated through oxidative pathways.
(4) Establishment of the genotoxic and mutagenic mode of action using gene expression arrays.

Graphene-induced toxicity on the population of intestinal microbiota and gut-associated immune response

Study Scientist: Sangeeta Khare

Evaluation of the effects of graphene on gastrointestinal homeostasis by determining graphene derivative effects on intestinal bacterial cultures, polarized intestinal epithelial cells, intestinal commensal bacteria in vivo, and gastrointestinal immune responses in vivo.

In vitro genotoxicity of graphene-family nanomaterials using FDA-recommended short-term genetic toxicity test battery

Study Scientist: Nan Mei

(1) Determination of the genotoxicity of graphene and derivatives in standard regulatory test battery assays.
(2) Determination of whether any mutagenicity in mouse lymphoma cells is due to loss of heterozygosity in chromosome 11.
(3) Investigation of whether genotoxic and mutagenic responses are mediated through oxidative pathways.
(4) Establishment of the genotoxic and mutagenic mode of action using gene expression arrays.

NCTR/Office of Regulatory Affairs (ORA) Nanotechnology Core Facility

Study Scientist: Anil Kumar Patri

(1) Provision of the expertise and equipment for characterizing nanomaterials used in toxicology studies and for detecting nanomaterials in in vitro and in vivo derived samples.
(2) Serving as a resource for U.S. agencies for the design of toxicology studies and generation of standards for analytical methods.

Assessment of whether engineered Ag nanomaterials (Ag-ENMs) varying by size and coatings behave differently from bulk Ag in their ability to induce genetic damage

Study Scientist: Tao Chen

(1) Evaluation of whether the Ames test and mouse lymphoma assay, in addition to the in vitro micronucleus assay, are suitable for detecting the genotoxicity of titanium dioxide (TiO2) nanoparticles, a known rodent carcinogen.
(2) Investigation of Ag-ENPs of various sizes and compare the results to those obtained using bulk Ag.

Determination of cytotoxicity and genotoxicity of nanomaterials of interest to the FDA and their mechanism of action

Study Scientist: Peter Fu

(1) Development of a set of cell-free and cell-based in vitro tests that can be used to rapidly identify nanomaterials of interest to the FDA that elicit oxidative damage.
(2) Determination of whether, in the presence of nano-metal materials, endogenous and dietary antioxidants can display pro-oxidative activity.

Assessing epigenetic effects of nanoparticles in human cells

Study Scientist: George Hammons

(1) Determination of the effect of two types of nanoparticles, silver and titanium dioxide, at various particle sizes, surface coatings, dosages, and durations of exposure on global methylation and genome-wide DNA methylation using array profiling in four types of human cells (liver, lung, skin, and colorectal).

(2) Determination of the effect of these nanoparticles on the pattern of global histone modifications and on genome-wide profiles of histone modifications in the four types of human cells. The analysis includes comparisons with disease-associated histone modifications.

(3) Correlation of the nanoparticle effect on DNA methylation with its effect on DNA methyltransferase expression.

(4) Correlation of the nanoparticle effect on global histone modifications with its effect on expression of histone-modifying enzymes as potential underlying mechanisms of the alteration in DNA methylation or histone modification patterns.

Immunotoxicity assessment of nanomaterials using human immune cell based biomarkers of innate immunity

Study Scientist: Wei Ding

Assessment of the immunotoxicity of different categories of nanoparticles using biomarkers of innate immunity measured in vitro in human immune cells (monocytes, human peripheral blood mononuclear cells).

An assessment of the interactions of nanoscale (TiO2 and zinc oxide) materials used in sunscreens on the skin microbiome

Study Scientist: Tao Chen

(1) Examination of human skin microbiota cell viability in the presence of nanoscale materials in cosmetics.

(2) Determination of the effect of nanomaterials in cosmetics on human skin microbial ecology.

(3) Demonstration of the mechanisms of toxicity of nanoscale materials in cosmetics to skin microbiota using the human skin tissue model EpiDerm and reverse transcription polymerase chain reaction (RT-PCR) and whole genome microarray technologies.

(4) Elucidation of the dose-response relationship of nanoscale materials in cosmetics on skin bacterial cell toxicity.

(5) Assessment of the potential health risk of human skin exposure to nanomaterials in cosmetics.

Evaluation of the migration and toxic potential of Ag nanoparticles in feminine hygiene products to vaginal tissue: In vivo rodent and in vitro 3D mucosal models

Study Scientist: Anil Patri

(1) Use of established qualitative methods to characterize different species of nanoscale Ag contained in five types of dry and five types of liquid feminine hygiene products.

(2) Evaluation of the migration/uptake and toxicity of Ag nanoparticles and ions used in feminine hygiene products using a human cell-based in vitro three-dimensional culture model that has many of the structural and functional features of the human vaginal mucosal layer.

(3) Evaluation of the effects of Ag nanoparticles and ions contained in feminine hygiene products on human vaginal microbiota using culture techniques and semiquantitative molecular methods.

Interaction of nanoparticles with gastrointestinal tract

Study Scientist: Sangeeta Khare

(1) Determination of the effect of nanomaterials on the permeability of epithelial cells and establishment of immune correlates.

(2) Delineation of the interaction of nanomaterials with gastrointestinal tract and gut-associated microbiota using an ex-vivo model (intestinal explants).

(3) Establishment of the effect of nanoparticles on the developmental stage of the intestine and assessment of the biodistribution of nanoparticles using the zebrafish model.

The effect of nanomaterials used in dentistry on biofilm formation and the oral microbiota

Study Scientist: John Sutherland

(1) Comparison of the relative efficacy of FDA-regulated nanomaterials used in dentistry for inhibition of bacterial adhesion to surfaces and biofilm formation.

(2) Evaluation of the effect of nanomaterials on growth and antimicrobial susceptibility profiles of typical species from the oral microbiota.

Mechanistic toxicological evaluation of engineered nanomaterials using a human stem cell model

Study Scientist: Anil Patri

(1) Establishment of the human stem cell model for nanotoxicity testing.

(2) Exploitation of the preliminary observation that titanium dioxide inhibits mesenchymal stem cell differentiation into adipocytes while other nanomaterials have no effect on the cells.

(3) Establishment of a novel sensitive model for nanotoxicity testing and provision of that information to FDA regulators on effects of titanium dioxide and other nanomaterials used in food, drugs, cosmetics, and medical products.

Development of cancer-relevant biomarkers for identification of potential carcinogens: Research to understand the normal background frequencies in rats

Study Scientist: Page McKinzie

(1) Understanding of the distribution and range of spontaneous oncogene mutant frequencies in the major organs of rats and mice.

(2) Provision of important basic information for the validation of these oncogene mutant frequencies as biomarkers of chemically induced carcinogenesis.

Validation of a newly developed transgenic, hairless, albino mouse

Study Scientist: Manju Manjanatha

Evaluation of a newly developed transgenic, hairless, albino mouse bearing a gpt-delta reporter construct (THA) for responsiveness of the construct (gpt and spi- red/gam genes) to UVB (ultraviolet B radiation). The animal will be used to examine kinetics of induction of UVB-induced mutations in a reporter construct in the dermis and epidermis and to correlate activity with UVB induction of skin tumors.

Study of translational biomarkers for drug-induced liver injury with next-generation sequencing

Study Scientist: Yuping Wang

Conduct of a comprehensive survey of microRNAs using the next generation sequencing technology. Findings will elucidate the molecular pathways and processes modulated by RNAs (including messenger RNAs, microRNAs, and other noncoding RNAs) and their importance in drug-induced liver injury risk and phenotypes.

A comprehensive characterization of induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) models for drug-induced arrhythmia using high-throughput screening assays

Study Scientist: Li Pang

(1) Development of standard baseline criteria for high-throughput readouts of drug-induced arrhythmia in human iPSC-CMs from different suppliers.

(2) Assessment of individual variance and possible sex differences in drug-induced cardiotoxic responses across a panel of nongenetically modified iPSC lines.

Validating the rat Pig-a assay for regulatory use: Determining the molecular basis of mutants detected in the rat Pig-a gene mutation assay

Study Scientist: Vasily Dobrovolsky

Development of a method that could routinely identify Pig-a mutations in individual Pig-a mutant phenotype cells.

Developing in vitro approaches to assess drug-induced liver toxicity

Study Scientist: Lei Guo

Development and utilization of in vitro assays for assessing drug-induced liver toxicity by evaluating cytotoxicity and quantifying representative endpoints for assessing clinical-related outcomes such as apoptosis/necrosis, steatosis, and cholestasis.

Evaluation of microRNAs in blood and urine for detection of chemical-induced carcinogenicity

Study Scientist: Tao Chen

(1) Determination of microRNAs in blood and carcinogenic target tissues that respond to carcinogen exposures and the best time for sampling of their expression after treatments in rats.

(2) Determination of microRNA profiles from the blood and target tissue samples of rats treated with different mode-of-action carcinogens, such as alkylating agents, aneugens, clastogens, and nongenotoxic carcinogens at the appropriate sampling time.

(3) Determination of the functions and pathways of the dysregulated microRNAs by the carcinogen treatments and examine whether the microRNA changes can be anchored to the carcinogens with the known mode-of-actions and whether the changes in blood are related to those in the target tissues.

(4) Establishment of specific microRNA biomarkers in blood for assessing different types of carcinogens.

Development and characterization of a diet-induced obesity model using B6C3F1 mouse for evaluation of drug toxicity in obesity

Study Scientist: Vijayalakshmi Varma

Development of a B6C3F1 mouse model of obesity to investigate the impact of obesity on anthracycline-induced cardiotoxicity and the model’s suitability to investigate other potential drug-induced toxicities under conditions of obesity.

Development of advanced safety assessments of FDA-regulated products using high-throughput and high-content quantitative approaches in cultured human cells to evaluate genotoxicity

Study Scientist: Carol Guo

Establishment and demonstration of the feasibility of novel high-throughput and high-content in vitro genotoxicity assays conducted using human liver cells in conjunction with quantitative dose-response approaches for assessing and distinguishing the genotoxicity of FDA-regulated products.

Enhance the prediction of potential endocrine activity of chemicals by integrating multiple endpoints data

Study Scientist: Huixiao Hong

(1) Augmentation of different endocrine-related endpoint data and development of prediction models for screening chemicals with endocrine activity potential by integrating the augmented multiple types of endocrine-related endpoint data.

(2) Building of an androgenic activity database and construction of integration-based prediction models.

Evaluation of an in vitro testis organ system as an alternative model for male reproductive toxicology

Study Scientist: Noriko Nakamura

Evaluation of the in vitro testis organ system as an alternative model to assess male reproductive toxicology and establishment of a standardized protocol for the assay.

Improving methods and algorithms for enhancing 3D-QSDAR

Study Scientist: Svetoslav Slavov

Testing of the feasibility and implementation of software code for enhancements to the three-dimensional quantitative spectral data-activity relationship (3D-QSDAR) technique and demonstration of the potential beneficial effect on the performance of 3D-QSDAR models for various data sets and endpoints.

Computational toxicology for safety and risk assessment

Study Scientist: Jeffery Fisher

Assistance to other FDA Centers and research organizations outside of FDA with their requests for support from staff scientists within NCTR and other scientists on safety and risk assessment issues of interest to FDA.

Pilot study to examine a population-based computational framework for assessing xenobiotic disposition and interaction effects in pregnant women

Study Scientist: Annie Lumen

(1) Demonstration of a proof of concept for using emerging computational techniques in understanding pregnancy-related alterations in drug pharmacokinetics.

(2) Assistance in developing recommendations for dose adjustments and drug labeling in the pregnant population, thus promoting women’s health during this crucial period.

Hepatoxicity of herbal/dietary supplements

Study Scientist: Weida Tong

Assembly of a comprehensive list of herbal and dietary supplements that have potential to cause drug-induced liver injury in humans into a web-based database that can be used for reference in regulatory processes when hepatotoxicity issues arise.