bioRxiv Science⌕ Search

Biology subjects

Krout, I. N.

Publications and source records attributed to Krout, I. N..

3 recordsLinked to original sources

The gut microbiome promotes detoxification responses to an environmental toxicant

At the host-environment interface, the indigenous microbiome is poised to facilitate interactions with exogenous components. Here, we show that the microbiome is necessary for metabolic and transcriptional detoxification responses to the neurotoxic pyrethroid insecticide, deltamethrin. While oral deltamethrin exposure shapes gut microbiome composition, it is not directly microbially metabolized. Instead, we observe microbiome-dependence on host hepatic and intestinal detoxification responses, with diminished activity in germ-free mice. Colonization with a complex microbiome in adulthood maintained limited hepatic responses, suggesting developmental contributions. However, mono-colonization with specific microbes increased colonic expression of a key detoxification enzyme, revealing a protective role for active microbial signaling in the colon. Overall, our data demonstrate that the microbiome is necessary to prime and activate a host response against a model environmental toxicant. Through both developmental and active signaling across organ compartments, these data support that the microbiome may contribute to risk and outcomes of toxicant-associated disease. HighlightsO_LIThe gut microbiome mediates the host response to environmental toxicants. C_LIO_LIKey xenobiotic metabolism genes are modulated by the microbiome C_LIO_LIEarly life signaling is necessary to promote hepatic responsiveness to toxicants in adulthood. C_LIO_LISpecific and active microbial signaling promotes colonic detoxification gene expression. C_LI

pharmacology and toxicology↗

The pyrethroid insecticide deltamethrin disrupts neuropeptide and monoamine signaling pathways in the gastrointestinal tract

Enteroendocrine cells (EECs) are a rare cell type of the intestinal epithelium. Various subtypes of EECs produce distinct repertoires of monoamines and neuropeptides which modulate intestinal motility and other physiologies. EECs also possess neuron-like properties, suggesting a potential vulnerability to ingested environmental neurotoxicants. One such group of toxicants are pyrethroids, a class of prevalent insecticides used residentially and agriculturally. Pyrethroids agonize voltage-gated sodium channels (VGSCs), inducing neuronal excitotoxicity, and affect the function of monoamine-producing neurons. Given their anatomical location at the interface with the environment and their expression of VGSCs, EECs likely represent a vulnerable cell-type to oral pyrethroid exposure. In this study, we used the EEC cell line, STC-1 cells, to evaluate the effects of the common pyrethroid deltamethrin on the functional status of EECs. We find that deltamethrin impacts both expression of serotonergic pathways and inhibits the adrenergic-evoked release of an EEC hormone, GLP-1, in vitro. In a mouse model of oral exposure, we found that deltamethrin induced an acute, yet transient, loss of intestinal motility, in both fed and fasted conditions. This constipation phenotype was accompanied by a significant decrease in peripheral serotonin production and an inhibition of nutrient-evoked intestinal hormone release. Together, these data demonstrate that deltamethrin alters monoaminergic signaling pathways in EECs and regulates intestinal motility. This work demonstrates a mechanistic link between pyrethroid exposure and intestinal impacts relevant to pyrethroid-associated diseases, including inflammatory bowel disease, neurodegenerative disease, and metabolic disorders.

pharmacology and toxicology↗

APP-KI mice do not display the hallmark age-dependent cognitive decline of amyloid diseases

APP knock-in (KI) mice serve as an exciting new model system to understand amyloid beta (A{beta}) pathology, overcoming many of the limitations of previous overexpression-based model systems. The APPSAA mouse model (containing the humanized APP with three familial Alzheimers disease mutations) and the APPWT control are the first commercially available APP KI mice within the United States. While APPSAA mice have been shown to develop progressive A{beta} pathology and neuroinflammation, behavioral changes, particularly in cognitive functions, have yet to be described. Therefore, we performed an in-depth longitudinal study over 12 months, assessing cognition in these two strains, as well as assessments of motor and GI function. We surprisingly note no overt, progressive cognitive impairment or motor deficits. However, we do observe a significant increase in fecal output in APPSAA mice compared to APPWT at 12 months old. These data provide a baseline for these models behavioral attributes. HighlightsO_LIAPPSAA and APPWT knock-in mice do not display age related cognitive decline C_LIO_LIFecal output appears altered by APP genotype, but no other measure of GI function is impacted. C_LIO_LIBoth genotypes behave equally in motor function tests C_LI

neuroscience↗