Faculty Bibliography

Numerous epidemiological and animal studies have demonstrated that exposure to ambient fine particulate matter (<2.5mum in diameter [PM2.5]) during gestation is associated with adverse obstetric outcomes including preterm birth (PTB). Early delivery has been linked to several lifetime health consequences for offspring, including behavioral and psychological abnormalities and reduced immune and respiratory functions. In a previous study performed in this laboratory, B6C3F1 pregnant mice exposed to concentrated ambient PM (CAPs) by inhalation, demonstrated shortened (by 0.4 d) gestational duration compared to filtered air (FA) controls. The mechanisms underlying the association between PM2.5 and PTB are not currently well understood. Since the placenta provides a crucial link between the intrauterine environment and fetal growth/development, it is a major target of PM and key for studying the effects on birth outcomes. Therefore, in this study, placentae from the previously developed pregnant mouse model (n=6 each from CAPs and FA groups) were subjected to whole transcriptomic profiling by RNAseq. A bioinformatic RNAseq analysis workflow (tximport, Salmon and edgeR /limmavoom) was used to identify differentially expressed genes between treatment groups. The 648 genes from the curated dbPTB (database Preterm Birth) were used for a candidate gene approach and were examined using gene counts obtained from RNAseq. Following PM2.5 exposure, six PTB genes were downregulated in placentae (Ace, Ddah1, Col1a2, Chst15, Akap12, Ephx1) and one was upregulated (Chys3) (p<0.01). Gene Ontology demonstrated that these seven genes are involved in neutrophil-mediated immunity, arterial blood pressure regulation, amino acid binding, cell membrane function, metal ion binding, and aromatic compound catabolism among other functions that could be linked to PTB. Additional computational models, agnostically testing placenta transcriptome-wide differential gene expression, revealed additional genes that were differentially expressed between the two treatment groups. These findings suggest that PM exposure influences the placenta genome thereby mediating PTB. Identification of these differentially expressed genes may contribute to intervention strategies to mitigate these adverse effects

World Trade Center (WTC) responders were exposed to mixture of dust, smoke, chemicals and carcinogens. New York University (NYU) and Mount Sinai have recreated WTC exposure in rodents to observe the resulting systemic and local biological responses. These experiments aid in the interpretation of epidemiological observations and are useful for understanding the carcinogenesis process in the exposed human WTC cohort. Here we describe the implementation of a tissue bank system for the rodents experimentally exposed to WTC dust. NYU samples were experimentally exposed to WTC dust via intratracheal inhalation that mimicked conditions in the immediate aftermath of the disaster. Tissue from Mount Sinai was derived from genetically modified mice exposed to WTC dust via nasal instillation. All processed tissues include annotations of the experimental design, WTC dust concentration/dose, exposure route and duration, genetic background of the rodent, and method of tissue isolation/storage. A biobank of tissue from rodents exposed to WTC dust has been compiled representing an important resource for the scientific community. The biobank remains available as a scientific resource for future research through established mechanisms for samples request and utilization. Studies using the WTC tissue bank would benefit from confirming their findings in corresponding tissues from organs of animals experimentally exposed to WTC dust. Studies on rodent tissues will advance the understanding of the biology of the tumors developed by WTC responders and ultimately impact the modalities of treatment, and the probability of success and survival of WTC cancer patients.

An excess incidence of prostate cancer has been identified among World Trade Center (WTC) responders. In this study, we hypothesized that WTC dust, which contained carcinogens and tumor-promoting agents, could facilitate prostate cancer development by inducing DNA damage, promoting cell proliferation, and causing chronic inflammation. We compared expression of immunologic and inflammatory genes using a NanoString assay on archived prostate tumors from WTC Health Program (WTCHP) patients and non-WTC patients with prostate cancer. Furthermore, to assess immediate and delayed responses of prostate tissue to acute WTC dust exposure via intratracheal inhalation, we performed RNA-seq on the prostate of normal rats that were exposed to moderate to high doses of WTC dust. WTC prostate cancer cases showed significant upregulation of genes involved in DNA damage and G₂-M arrest. Cell-type enrichment analysis showed that Th17 cells, a subset of proinflammatory Th cells, were specifically upregulated in WTC patients. In rats exposed to WTC dust, we observed upregulation of gene transcripts of cell types involved in both adaptive immune response (dendritic cells and B cells) and inflammatory response (Th17 cells) in the prostate. Unexpectedly, genes in the cholesterol biosynthesis pathway were also significantly upregulated 30 days after acute dust exposure. Our results suggest that respiratory exposure to WTC dust can induce inflammatory and immune responses in prostate tissue.Implications: WTC-related prostate cancer displayed a distinct gene expression pattern that could be the result of exposure to specific carcinogens. Our data warrant further epidemiologic and cellular mechanistic studies to better understand the consequences of WTC dust exposure.Visual Overview: http://mcr.aacrjournals.org/content/early/2019/06/18/1541-7786.MCR-19-0115/F1.large.jpg.

Approximately 1 million women smoke during pregnancy despite evidence demonstrating serious juvenile and/or adult diseases being linked to early-life exposure to cigarette smoke. Susceptibility could be determined by factors in previous generations, that is, prenatal or "maternal" exposures to toxins. Prenatal exposure to airborne pollutants such as mainstream cigarette smoke has been shown to induce early-life insults (i.e., gene changes) in Offspring that serve as biomarkers for disease later in life. In this investigation, we have evaluated genome-wide changes in the lungs of mouse Dams and their juvenile Offspring exposed prenatally to mainstream cigarette smoke. An additional lung model was tested alongside the murine model, as a means to find an alternative in vitro, human tissue-based replacement for the use of animals in medical research. Our toxicogenomic and bio-informatic results indicated that in utero exposure altered the genetic patterns of the fetus, which could put them at greater risk for developing a range of chronic illnesses in later life. The genes altered in the in vitro, cell culture model were reflected in the murine model of prenatal exposure to mainstream cigarette smoke. The use of alternative in vitro models derived from human medical waste tissues could be viable options to achieve human endpoint data and conduct research that meets the remits for scientists to undertake the 3Rs practices.

Accumulating evidence indicates the developing central nervous system (CNS) is a target of air pollution toxicity. Epidemiological reports increasingly demonstrate that exposure to the particulate matter (PM) fraction of air pollution during neurodevelopment is associated with an increased risk of neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD). These observations are supported by animal studies demonstrating prenatal exposure to concentrated ambient PM induces neuropathologies characteristic of ASD, including ventriculomegaly and aberrant corpus callosum (CC) myelination. Given the role of the CC and cerebellum in ASD etiology, this study tested whether prenatal exposure to concentrated ambient particles (CAPs) produced pathological features in offspring CC and cerebella consistent with ASD. Analysis of cerebellar myelin density revealed male-specific hypermyelination in CAPs-exposed offspring at postnatal days (PNDs) 11-15 without alteration of cerebellar area. Atomic absorption spectroscopy (AAS) revealed elevated iron (Fe) in the cerebellum of CAPs-exposed female offspring at PNDs 11-15, which connects with previously observed elevated Fe in the female CC. The presence of Fe inclusions, along with aluminum (Al) and silicon (Si) inclusions, were confirmed at nanoscale resolution in the CC along with ultrastructural myelin sheath damage. Furthermore, RNAseq and gene ontology (GO) enrichment analyses revealed cerebellar gene expression was significantly affected by sex and prenatal CAPs exposure with significant enrichment in inflammation and transmembrane transport processes that could underlie observed myelin and metal pathologies. Overall, this study highlights the ability of PM exposure to disrupt myelinogenesis and elucidates novel molecular targets of PM-induced developmental neurotoxicity.

Syngeneic murine tumor models have been widely used by researchers to assess changes in tumor susceptibility associated with exposure to toxicants. Two common tumor models used to define host resistance against transplanted tumors in vivo are EL4 mouse lymphoma cells (established from a lymphoma induced in a C57BL/6 mouse by 9,10-dimethyl-1,2-benzanthracene) and B16F10 mouse melanoma cells (derived through variant selection from a B16 melanoma arising spontaneously in C57BL/6 mice). While C57BL/6 mice are commonly used as the syngeneic host for these tumor models, other mouse strains such as B₆C₃F₁ (C57BL/6 × C3H) can also be used. Tumor challenge of the host can be done by subcutaneous (sc) or intravenous (iv) injection, depending upon whether the effects are to be examined on local tumor development or experimental/artificial metastasis. Materials and methodologies for injection of both tumor cell models are described in detail in the subsequent sections.

Xenobiotic exposures affect the maternal and/or in utero environment resulting in impairments in fetal development. During the period of rapid fetal growth, developing cardiovascular systems are especially vulnerable to their environment. Furthermore, fetal exposures can evoke changes in epigenetic signatures that result in permanent modifications in gene expression. This symposium focused on the intersection between maternal and fetal exposure and the developing cardiovascular system. The impact of maternal exposures on prenatal development is of major concern for regulatory agencies given the unique vulnerability of the embryo/fetus to environmental factors, the importance of vascular biology to maternal-fetal interactions, and the adverse consequences of vascular disruption to children's health. Speakers provided data from diverse exposures: nanomaterials, particulate matter or air pollution (PM_2.5), nicotine, and environmental chemicals. The current findings related to susceptible gestational windows for cardiovascular development and epigenetic, transcriptomic, toxicokinetic, and toxicodynamic changes in vascular physiology and cardiac function. In response to these concerns, new concepts in predictive modeling and risk assessment associated with in utero exposures were presented as future avenues of research within developmental toxicology. Finally, current applications using an Adverse Outcome Pathway framework for developmental toxicity were presented to integrate data from in vitro profiling of chemical libraries (e.g. ToxCastâ„¢) with computational models for in silico toxicology. In summary, this symposium addressed the significant threats to cardiovascular health that are associated with fetal/perinatal exposures, and offered new insights into the predictive, mechanistic, and risk assessment strategies in developmental toxicology.

Recent epidemiological data indicate that the popularity of electronic cigarettes (e-cigarettes), and consequently nicotine use, is rising in both adolescent and adult populations. As nicotine is a known developmental neurotoxin, these products present a potential threat for those exposed during early life stages. Despite this, few studies have evaluated the toxicity of e-cigarettes on the developing central nervous system (CNS). The goal of this study was to assess neurotoxicity resulting from early life exposure to electronic cigarette aerosols in an in vivo model. Specifically, studies here focused on neuro-parameters related to neuroinflammation and neurotrophins. To accomplish this, pregnant and neonatal C57BL/6 mice were exposed to aerosols produced from classic tobacco flavor e-cigarette cartridges (with [13 mg/ml] and without nicotine) during gestation ( approximately 3-wk) and lactation ( approximately 3-wk) via whole-body inhalation. Exposure to e-cigarette aerosols with and without nicotine caused significant reductions in hippocampal gene expression of Ngfr and Bdnf, as well as in serum levels of cytokines IL-1beta, IL-2 and IL-6. Exposure to e-cigarette aerosols without nicotine enhanced expression of Iba-1, a specific marker of microglia, in the CA1 region of the hippocampus. Overall, our novel results indicate that exposure to e-cigarette aerosols, with and without nicotine, poses a considerable risk to the developing CNS. Consequently, e-cigarettes should be considered a potential public health threat, especially early in life, requiring further research and policy considerations.

Exposure to fine ambient particulates (PM2.5) during gestation or neonatally has potent neurotoxic effects. While biological and behavioral data indicate a vulnerability to environmental pollutants across distinct neurodevelopmental windows, the behavioral consequences following exposure across the entire developmental period remain unknown. Moreover, several epidemiological studies support a link between developmental exposure to air pollution and an increased risk of later receiving a diagnosis of autism spectrum disorders (ASD), a neurodevelopmental disorder that persists throughout life. In the current study we sought to determine whether perinatal exposure to PM2.5 would reduce sociability and increase repetitive deficits in mice, two hallmark characteristics of ASD. Pregnant female B6C3 mice were exposed daily to concentrated ambient PM2.5 (CAPs) (135.8mug/m3) or filtered air (3.1mug/m3) throughout gestation followed by additional exposures to both dams and their litters from days 2-10 postpartum. Adult offspring were subsequently assessed for social and repetitive behaviors at 20 weeks of age. Daily perinatal exposure to CAPs significantly decreased sociability in male and female mice as measured by the social approach task; however, reductions in reciprocal social interaction and increased grooming behavior were only present in male offspring exposed to CAPs. These findings demonstrate that exposure to particulate air pollutants throughout early neurodevelopment induces long lasting behavioral deficits in a sex-dependent manner and may be an underlying cause of neurodevelopmental disorders such as ASD.