Improving Outreach and Surveillance Efforts Following a Large-Scale Carbon Monoxide Poisoning in Wisconsin.

OBJECTIVE: In December 2014, the largest carbon monoxide (CO) poisoning in Wisconsin's history occurred at an ice arena. Following this event, the Wisconsin Environmental Public Health Tracking (WI EPHT) Program sought to improve outreach and surveillance efforts. METHODS: WI EPHT designed and distributed educational materials on CO poisoning prevention and surveyed stakeholders to gauge the effectiveness of outreach efforts. To enhance surveillance, WI EPHT utilized data from the Wisconsin Poison Center (WPC) to generate real-time alerts of anomalous numbers of CO-related calls. RESULTS: WI EPHT found that 42% of stakeholders reviewed the outreach materials, and 1 ice arena had installed a CO detector as a result. CO alerts were developed using WPC data and are now routinely used in statewide public health surveillance. CONCLUSION: WI EPHT staff improved CO poisoning prevention outreach and saw a positive response among stakeholders. This work demonstrates ways that health agencies can improve outreach and surveillance for CO poisoning. Improvements in these areas can bolster public health response and may prevent CO-related illness and injury.

Mercury Spill Responses - Five States, 2012-2015.

Despite measures to educate the public about the dangers of elemental mercury, spills continue to occur in homes, schools, health care facilities, and other settings, endangering the public's health and requiring costly cleanup. Mercury is most efficiently absorbed by the lungs, and exposure to high levels of mercury vapor after a release can cause cough, sore throat, shortness of breath, nausea, vomiting, diarrhea, headaches, and visual disturbances (1). Children and fetuses are most susceptible to the adverse effects of mercury vapor exposure. Because their organ systems are still developing, children have increased respiratory rates, and they are closer to the ground where mercury vapors are most highly concentrated (2). To summarize key features of recent mercury spills and lessons learned, five state health departments involved in the cleanup (Iowa, Michigan, Missouri, North Carolina, and Wisconsin) compiled data from various sources on nonthermometer mercury spills from 2012 to 2015. The most common sites of contamination were residences, schools and school buses, health care facilities, and commercial and industrial facilities. Children aged <18 years were present in about one third of the spills, with approximately one in seven incidents resulting in symptoms consistent with acute mercury exposure. To protect the public's health after a mercury spill, it is important that local, state, and federal agencies communicate and coordinate effectively to ensure a quick response, and to minimize the spread of contamination. To reduce the number of mercury spills that occur in the United States, public health officials should increase awareness about exchange programs for mercury-containing items and educate school and health care workers about sources of mercury and how to dispose of them properly.

Exposure to Elevated Carbon Monoxide Levels at an Indoor Ice Arena--Wisconsin, 2014.

On December 13, 2014, the emergency management system in Lake Delton, Wisconsin, was notified when a male hockey player aged 20 years lost consciousness after participation in an indoor hockey tournament that included approximately 50 hockey players and 100 other attendees. Elevated levels of carbon monoxide (CO) (range = 45 ppm-165 ppm) were detected by the fire department inside the arena. The emergency management system encouraged all players and attendees to seek medical evaluation for possible CO poisoning. The Wisconsin Department of Health Services (WDHS) conducted an epidemiologic investigation to determine what caused the exposure and to recommend preventive strategies. Investigators abstracted medical records from area emergency departments (EDs) for patients who sought care for CO exposure during December 13-14, 2014, conducted a follow-up survey of ED patients approximately 2 months after the event, and conducted informant interviews. Ninety-two persons sought ED evaluation for possible CO exposure, all of whom were tested for CO poisoning. Seventy-four (80%) patients had blood carboxyhemoglobin (COHb) levels consistent with CO poisoning; 32 (43%) CO poisoning cases were among hockey players. On December 15, the CO emissions from the propane-fueled ice resurfacer were demonstrated to be 4.8% of total emissions when actively resurfacing and 2.3% when idling, both above the optimal range of 0.5%-1.0%. Incomplete fuel combustion by the ice resurfacer was the most likely source of elevated CO. CO poisonings in ice arenas can be prevented through regular maintenance of ice resurfacers, installation of CO detectors, and provision of adequate ventilation.

Epigenetic mediated transcriptional activation of WNT5A participates in arsenical-associated malignant transformation.

Arsenic is a human carcinogen with exposure associated with cancer of the lung, skin, and bladder. Many potential mechanisms have been implicated as playing a role in the process of arsenical-induced malignancy including the perturbation of signaling pathways and aberrant epigenetic regulation. We initiated studies to examine the role of a member of the non-canonical WNT signaling pathway, WNT5A, in UROtsa cells and arsenite [URO-ASSC] and monomethylarsonous acid [URO-MSC] malignantly transformed variants. We present data herein that suggest that WNT5A is transcriptionally activated during arsenical-induced malignant transformation. This WNT5A transcriptional activation is correlated with the enrichment of permissive histone modifications and the reduction of repressive modifications in the WNT5A promoter region. The epigenetic activation of WNT5A expression and acetylation of its promoter remain after the removal of the arsenical, consistent with the maintenance of an anchorage independent growth phenotype in these cells. Additionally, treatment with epigenetic modifying drugs supports a functional role for these epigenetic marks in controlling gene expression. Reduction of WNT5A using lentiviral shRNA greatly attenuated the ability of these cells to grow in an anchorage independent fashion. Extension of our model into human bladder cancer cell lines indicates that each of the cell lines examined also express WNT5A. Taken together, these data suggest that the epigenetic remodeling of the WNT5A promoter is correlated with its transcriptional activation and this upregulation likely participates in arsenical-induced malignant transformation.

Molecular hallmarks of endogenous chromatin complexes containing master regulators of hematopoiesis.

Combinatorial interactions among trans-acting factors establish transcriptional circuits that orchestrate cellular differentiation, survival, and development. Unlike circuits instigated by individual factors, efforts to identify gene ensembles controlled by multiple factors simultaneously are in their infancy. A paradigm has emerged in which the important regulators of hematopoiesis GATA-1 and GATA-2 function combinatorially with Scl/TAL1, another key regulator of hematopoiesis. The underlying mechanism appears to involve preferential assembly of a multimeric complex on a composite DNA element containing WGATAR and E-box motifs. Based on this paradigm, one would predict that GATA-2 and Scl/TAL1 would commonly co-occupy such composite elements in cells. However, chromosome-wide analyses indicated that the vast majority of conserved composite elements were occupied by neither GATA-2 nor Scl/TAL1. Intriguingly, the highly restricted set of GATA-2-occupied composite elements had characteristic molecular hallmarks, specifically Scl/TAL1 occupancy, a specific epigenetic signature, specific neighboring cis elements, and preferential enhancer activity in GATA-2-expressing cells. Genes near the GATA-2-Scl/TAL1-occupied composite elements were regulated by GATA-2 or GATA-1, and therefore these fundamental studies on combinatorial transcriptional mechanisms were also leveraged to discover novel GATA factor-mediated cell regulatory pathways.

Epigenetic control of complex loci during erythropoiesis.

Epigenetic mechanisms involving dynamic changes in posttranslational histone modifications commonly control gene transcription and therefore the execution of all cellular differentiation programs. The differentiation of hematopoietic stem cells into specific progenitor cells and the diverse blood cell types represents a particularly powerful system for the study of epigenetic mechanisms. The hematopoietic system allows one to define mechanisms underlying the establishment and regulation of histone modification patterns covering entire genes and/or chromosomes at distinct stages of differentiation. This chapter reviews progress in elucidating principles underlying epigenetic control of complex loci, specifically focusing on genes differentially expressed during hematopoiesis.

Context-dependent GATA factor function: combinatorial requirements for transcriptional control in hematopoietic and endothelial cells.

GATA factors are fundamental components of developmentally important transcriptional networks. By contrast to common mechanisms in which transacting factors function directly at promoters, the hematopoietic GATA factors GATA-1 and GATA-2 often assemble dispersed complexes over broad chromosomal regions. For example, GATA-1 and GATA-2 occupy five conserved regions over approximately 100 kb of the Gata2 locus in the transcriptionally repressed and active states, respectively, in erythroid cells. Since it is unknown whether the individual complexes exert qualitatively distinct or identical functions to regulate Gata2 transcription in vivo, we compared the activity of the -3.9 and +9.5 kb sites of the Gata2 locus in transgenic mice. The +9.5 site functioned as an autonomous enhancer in the endothelium and fetal liver of embryonic day 11 embryos, whereas the -3.9 site lacked such activity. Mechanistic studies demonstrated critical requirements for a GATA motif and a neighboring E-box within the +9.5 site for enhancer activity in endothelial and hematopoietic cells. Surprisingly, whereas this GATA-E-box composite motif was sufficient for enhancer activity in an erythroid precursor cell line, its enhancer function in primary human endothelial cells required additional regulatory modules. These results identify the first molecular determinant of Gata2 transcription in vascular endothelium, composed of a core enhancer module active in both endothelial and hematopoietic cells and regulatory modules preferentially required in endothelial cells.

Epigenetic inactivation of the HOXA gene cluster in breast cancer.

Using an integrated approach of epigenomic scanning and gene expression profiling, we found aberrant methylation and epigenetic silencing of a small neighborhood of contiguous genes-the HOXA gene cluster in human breast cancer. The observed transcriptional repression was localized to approximately 100 kb of the HOXA gene cluster and did not extend to genes located upstream or downstream of the cluster. Bisulfite sequencing, chromatin immunoprecipitation, and quantitative reverse transcription-PCR analysis confirmed that the loss of expression of the HOXA gene cluster in human breast cancer is closely linked to aberrant DNA methylation and loss of permissive histone modifications in the region. Pharmacologic manipulations showed the importance of these aberrant epigenetic changes in gene silencing and support the hypothesis that aberrant DNA methylation is dominant to histone hypoacetylation. Overall, these data suggest that inactivation of the HOXA gene cluster in breast cancer may represent a new type of genomic lesion-epigenetic microdeletion. We predict that epigenetic microdeletions are common in human cancer and that they functionally resemble genetic microdeletions but are defined by epigenetic inactivation and transcriptional silencing of a relatively small set of contiguous genes along a chromosome, and that this type of genomic lesion is metastable and reversible in a classic epigenetic fashion.

Epigenetic regulation of the cell type-specific gene 14-3-3sigma.

Epigenetic control participates in processes crucial in mammalian development, such as X-chromosome inactivation, gene imprinting, and cell type-specific gene expression. We provide evidence that the p53-inducible gene 14-3-3sigma is a new example of a gene important to human cancer, where epigenetic mechanisms participate in the control of normal cell type-specific expression, as well as aberrant gene silencing in cancer cells. Like a previously identified cell type-specific gene maspin, 14-3-3sigma is a p53-inducible gene; however, it participates in G2/M arrest in response to DNA-damaging agents. 14-3-3Sigma expression is restricted to certain epithelial cell types, including breast and prostate, whereas expression is absent in nonepithelial tissues such as fibroblasts and lymphocytes. In this report, we show that in normal cells expressing 14-3-3sigma, the 14-3-3sigma CpG island is unmethylated; associated with acetylated histones, unmethylated histone H3 lysine 9; and an accessible chromatin structure. By contrast, normal cells that do not express 14-3-3sigma have a methylated 14-3-3sigma CpG island with hypoacetylated histones, methylated histone H3 lysine 9, and an inaccessible chromatin structure. These findings extend the spectrum of cell type-specific genes controlled, partly, by normal epigenetic mechanisms, and suggest that this subset of genes may represent important targets of epigenetic dysregulation in human cancer.

Epigenetic silencing of DSC3 is a common event in human breast cancer.

INTRODUCTION: Desmocollin 3 (DSC3) is a member of the cadherin superfamily of calcium-dependent cell adhesion molecules and a principle component of desmosomes. Desmosomal proteins such as DSC3 are integral to the maintenance of tissue architecture and the loss of these components leads to a lack of adhesion and a gain of cellular mobility. DSC3 expression is down-regulated in breast cancer cell lines and primary breast tumors; however, the loss of DSC3 is not due to gene deletion or gross rearrangement of the gene. In this study, we examined the prevalence of epigenetic silencing of DSC3 gene expression in primary breast tumor specimens. METHODS: We used bisulfite genomic sequencing to analyze the methylation state of the DSC3 promoter region from 32 primary breast tumor specimens. We also used a quantitative real-time RT-PCR approach, and analyzed all breast tumor specimens for DSC3 expression. Finally, in addition to bisulfite sequencing and RT-PCR, we used an in vivo nuclease accessibility assay to determine the chromatin architecture of the CpG island region from DSC3-negative breast cancer cells lines. RESULTS: DSC3 expression was downregulated in 23 of 32 (72%) breast cancer specimens comprising: 22 invasive ductal carcinomas, 7 invasive lobular breast carcinomas, 2 invasive ductal carcinomas that metastasized to the lymph node, and a mucoid ductal carcinoma. Of the 23 specimens showing a loss of DSC3 expression, 13 (56%) were associated with cytosine hypermethylation of the promoter region. Furthermore, DSC3 expression is limited to cells of epithelial origin and its expression of mRNA and protein is lost in a high proportion of breast tumor cell lines (79%). Lastly, DNA hypermethylation of the DSC3 promoter is highly correlated with a closed chromatin structure. CONCLUSION: These results indicate that the loss of DSC3 expression is a common event in primary breast tumor specimens, and that DSC3 gene silencing in breast tumors is frequently linked to aberrant cytosine methylation and concomitant changes in chromatin structure.

The acetyltransferase p300/CBP-associated factor is a p53 target gene in breast tumor cells.

p300/CBP-associated factor (PCAF) is a coactivator of the tumor suppressor, p53. PCAF participates in p53's transactivation of target genes through acetylation of both bound p53 and histones within p53 target promoters. Using microarrays, we discovered that PCAF itself is induced by p53 in a panel of breast tumor cell lines. Two p53 mutant breast tumor cell lines, BT-549 and UACC-1179, were chosen for further study of PCAF induction by wild-type p53. PCAF induction following adenoviral transduction of p53 expression was confirmed with real-time polymerase chain reaction in a time course experiment. Chromatin immunoprecipitation experiments then showed that PCAF induction was associated with increased p53 binding to the PCAF promoter, which contains p53 consensus-binding sites. PCAF induction by p53 activity was further demonstrated in wild-type p53 MCF10A cells when PCAF expression was induced following activation of endogenous wild-type p53 with doxorubicin in a dose- and time-dependent manner. Furthermore, the doxorubicin-induced increase in PCAF expression was blocked by pretreatment of the MCF10A cells with siRNA (small interfering RNA) targeted against p53 mRNA. Taken together, the results show that PCAF expression can be induced by wild-type p53.

Mutant p53 and aberrant cytosine methylation cooperate to silence gene expression.

p53 is an important transcriptional regulator that is frequently mutated in cancer. Gene-profiling experiments of breast cancer cells infected with wt p53 revealed both MASPIN and desmocollin 3 (DSC3) to be p53-target genes, even though both genes are silenced in association with aberrant cytosine methylation of their promoters. Despite the transcriptional repression of these genes by aberrant DNA methylation, restoration of p53 resulted in the partial reactivation of both genes. This reactivation is a result of wt p53 binding to its consensus DNA-binding sites within the MASPIN and DSC3 promoters, stimulating histone acetylation, and enhancing chromatin accessibility of their promoters. Interestingly, wt p53 alone did not affect the methylation status of either promoter, suggesting that p53 itself can partially overcome the repressive barrier of DNA methylation. Pharmacologic inhibition of DNA methylation with 5-aza-2'-deoxycytidine in combination with restoration of wt p53 status resulted in a synergistic reactivation of these genes to near-normal levels. These results suggest that cancer treatments that target both genetic and epigenetic facets of gene regulation may be a useful strategy towards the therapeutic transcriptional reprogramming of cancer cells.

Role for DNA methylation in the control of cell type specific maspin expression.

The nucleotide 5-methylcytosine is involved in processes crucial in mammalian development, such as X-chromosome inactivation and gene imprinting. In addition, cytosine methylation has long been speculated to be involved in the establishment and maintenance of cell type specific expression of developmentally regulated genes; however, it has been difficult to identify clear examples of such genes, particularly in humans. Here we provide evidence that cytosine methylation of the maspin gene (SERPINB5) promoter controls, in part, normal cell type specific SERPINB5 expression. In normal cells expressing SERPINB5, the SERPINB5 promoter is unmethylated and the promoter region has acetylated histones and an accessible chromatin structure. By contrast, normal cells that do not express SERPINB5 have a completely methylated SERPINB5 promoter with hypoacetylated histones, an inaccessible chromatin structure and a transcriptional repression that is relieved by inhibition of DNA methylation. These findings indicate that cytosine methylation is important in the establishment and maintenance of cell type restricted gene expression.