Genome‐wide expression reveals multiple systemic effects associated with detection of anticoagulant poisons in bobcats (Lynx rufus)

Abstract

Anticoagulant rodenticides (ARs) are indiscriminate toxicants that threaten nontarget predatory and scavenger species through secondary poisoning. Accumulating evidence suggests that AR exposure may have disruptive sublethal consequences on individuals that can affect fitness. We evaluated AR-related effects on genome-wide expression patterns in a population of bobcats in southern California. We identify differential expression of genes involved in xenobiotic metabolism, endoplasmic reticulum stress response, epithelial integrity and both adaptive and innate immune function. Further, we find that differential expression of immune-related genes may be attributable to AR-related effects on leucocyte differentiation. Collectively, our results provide an unprecedented understanding of the sublethal effects of AR exposure on a wild carnivore. These findings highlight potential detrimental effects of ARs on a wide variety of species worldwide that may consume poisoned rodents and indicate the need to investigate gene expression effects of other toxicants added to natural environments by humans.

Widespread Anticoagulant Poison Exposure is Linked with Immune Dysregulation and Severe Notoedric Mange in Urban Bobcats

“…The park encompasses both large regions of continuous protected habitat with minimal urban development, including state and national park lands, and highly fragmented areas with intense urban development. Long-term urban bobcat research by the National Park Service allowed us to integrate information collected between 1996-2012 on bobcat demography, disease status, population dynamics, mortality, physiological and immunological parameters, gene expression, and AR exposure (see Serieys et al 2015a, Fraser and Mouton et al 2018 for more detailed methods).…”

“…Fourth, in 52 live-captured individuals also represented in Serieys et al (2018), we quantified sublethal AR-related effects on genome-wide expression patterns in blood (Fraser and Mouton et al 2018). Twenty-six individuals were documented exposed to ARs, while 26 individuals were documented as unexposed.…”

“…To isolate the effects of ARs on immune and gene expression parameters while controlling for disease status and demographic factors, we used a variety of statistical approaches (Fraser andMouton et al 2018, Serieys et al 2018). In brief, because demography (age class and sex), season of sample collection, and disease exposure or infection status may also have strong effects on immune function, we used principal components analysis (PCA) to determine which of these parameters explained significant variance in our datasets.…”

“…The epizootic had profound population-level impacts, significantly reducing the effective population size and causing a genetic bottleneck (Serieys et al 2015b). While susceptibility to severe mange in California bobcats has been linked to repeated, cumulative first-and secondgeneration AR exposure (Riley et al 2007, Serieys et al 2015a, the mechanism by which AR exposure could increase disease susceptibility was unknown until very recently (Fraser andMouton et al 2018, Serieys et al 2018).…”

“…Here, we summarize the approaches we took to robustly investigate the breadth and impacts of ARs in the southern California urban bobcat population affected by mange in an effort to understand the potential causal link between ARs and mange. Specifically, we: 1) investigated how widespread AR exposure was in this population (Serieys et al 2015a), 2) tested the association between anticoagulant rodenticide exposure and death due to notoedric mange (Serieys et al 2015a), 3) investigated the influence of ARs on the physiological and immunological health of live-captured bobcats , and 4) quantified differential gene expression profiles of apparently healthy free-ranging bobcats both exposed, and unexposed, to ARs in SMMNRA (Fraser and Mouton et al 2018).…”