Identification of genotoxic compounds in crude oil using fractionation according to distillation, polarity and Kow

The Impact of the Deepwater Horizon Oil Spill upon Lung Health-Mouse Model-Based RNA-Seq Analyses

We used a transcriptomic approach to interrogate the effects of a saline-accommodated fraction from the Macondo 252 well (MC252) oil and Corexit dispersants on lung tissue. Wild-type C57BL/6 male and female mice were exposed on days 0, 7 and 13 by oropharyngeal aspiration to saline accommodated fractions (SAF) of crude oil from the Macondo (MC252) well, Corexit 9500, Corexit 9527, 9500+oil and 9527+oil or a saline solution as the vehicle control. These treatments did not cause overt toxicity, with the exception of the Corexit exposures which caused brief weight loss after the first exposure. On day 14, total RNA was isolated from the left lung for RNA-seq analyses. KEGG-pathway-based differential expression revealed that Corexit 9527 elicited the strongest changes involving the upregulation of 19 KEGG pathways (FDR < 0.10), followed by Corexit 9500 with the upregulation of seven pathways (FDR < 0.10). As an important signature, pathways related to a response to DNA damage (e.g., p53 signaling and mismatch repair) dominate those upregulated by Corexit 9527 and Corexit 9500. In addition, pro-inflammatory pathways (e.g., cytokine-cytokine receptor interaction, IL-17 signaling pathway and TNF signaling pathways) were upregulated selectively in oil-treated male mice. Surprisingly, oil + dispersant combinations caused lesser effects than the individual treatments at the transcriptomic level. Overall, these findings support potential genotoxicity, inflammation and cell death due to dispersant or oil exposures. Similar exposures to lung tumor bearing K-Ras^LA1 mice provided evidence for tumor promotion by oil and Corexit dispersant treatments. Our mouse RNA-seq analyses may be relevant to the pulmonary health hazards of MC252 oil and dispersants experienced in exposed populations.

Dominant-Negative DISC1 Alters the Dopaminergic Modulation of Inhibitory Interneurons in the Mouse Prefrontal Cortex

A truncated disrupted in schizophrenia 1 (Disc1) gene increases the risk of psychiatric disorders, probably affecting cortical interneurons. Here, we sought to determine whether this cell population is affected in mice carrying a truncated (Disc1) allele (DN-DISC1). We utilized whole cell recordings to assess electrophysiological properties and modulation by dopamine (DA) in two classes of interneurons: fast-spiking (FS) and low threshold-spiking (LTS) interneurons in wild-type and DN-DISC1 mice. In DN-DISC1 mice, FS interneurons, but not LTS interneurons, exhibited altered action potentials. Further, the perineuronal nets that surround FS interneurons exhibited abnormal morphology in DN-DISC1 mice, and the DA modulation of this cell type was altered in DN-DISC1 mice. We conclude that early-life manipulation of a gene associated with risk of psychiatric disease can result in dysfunction, but not loss, of specific GABAergic interneurons. The resulting alteration of excitatory-inhibitory balance is a critical element in DISC1 pathophysiology.