A Neurovascular Unit on Chip for Reducing Animals in Organophosphate Neurotoxicology

EPA Grant Number: R839504
Title: A Neurovascular Unit on Chip for Reducing Animals in Organophosphate Neurotoxicology
Investigators: Cliffel, David , May, Jody , McLaughlin, BethAnn
Current Investigators: Cliffel, David , May, Jody , McLaughlin, BethAnn , Neely, M Diana
Institution: Vanderbilt University , Vanderbilt University Medical Center
EPA Project Officer: Callan, Richard
Project Period: August 1, 2019 through July 31, 2020 (Extended to July 31, 2023)
Project Amount: $850,000
RFA: Advancing Actionable Alternatives to Vertebrate Animal Testing for Chemical Safety Assessment (2018) RFA Text |  Recipients Lists
Research Category: Chemical Safety for Sustainability

Description:

The blood brain barrier (BBB) is the most critical form of protection that the human brain has. Comprised of three types of cells, neurons, glia and endothelial cells, the BBB uses a combination of physical and chemical signaling to triage every chemical, ion and protein within the bloodstream and determine which can pass safely into the brain and block those which present a potential danger. While the integrity and function of the BBB are critical for human health, we have lacked tools to understand the signals that move between cells to protect the brain. Identifying adaptive and maladaptive function of the BBB is increasingly important in a world where humans are exposed to unique and potentially dangerous chemicals. To meet challenge of understanding BBB biology, we have developed a first of its kind organ on a chip platform that faithfully replicates the cellular diversity, permeability and metabolic signaling of the BBB. This "Neurovascular Unit (NVU)" offers unique opportunities to identify the molecules, metabolites and chemical signals that ensure appropriate neuronal development cues are present and understand how likely toxins subvert the sential process. The NVU offers means to dynamically assess metabolic and signaling within and between BBB cells without the ethical and practical limitations posed by in vivo studies of animals or the lack of sensitivity observed in standard cell death/morphology toxicology assays in cell lines.

Objective:

The goal of this program is to demonstrate that the NVU a dramatically improved means to understand the mechanism of organophosphate subversion of BBB function by assessing the toxicity and signaling of chlorpyrifos.

Approach:

By combining microclinical analzyers, small molecules targeting specific cellular compartments and signaling cascades, we will assess the acute and chronic responses underlying the changes in BBB integrity, neuronal vulnerability and brain injury subsequent to organophosphate exposure. Our approach has the advantage providing quantitative information regarding a variety of cellular activities, including metabolism, membrane transport, protein translation, immune response and hence provides a comprehensive approach to absorption, distribution, metabolism, excretion (ADME) and toxicological (TOX) profiles.

Expected Results:

By sampling microenvironments created by NVUs we can track and measure the ability of both chlorpyrifos and its metabolites to cross the blood-brain barrier in both a dose and time dependent manner. Using untargeted metabolomics screening of mass spectrometry data, our early findings suggests that chlorpyrifos triggers rapid changes in cellular bioenergetic status, mitochondrial failure and massive neurotransmitter dysfunction within the neuronal subcompartment. By repeating these in situ measurements every 2 minutes for hours to days, our goal is to track the changes in metabolic and signaling activity associated with toxin-induced shifts in cellular homeostasis even at subtoxic exposures By combining individual and equipment with expertise in neurobiology, microanalyte detection and metabolomics, these platforms can be used to address critical biological questions and significantly reduce the need for use of animals in laboratory toxicology research. A comparison is done between chlorpyrifos, paraoxon, and parathion to previous animal testing results.

Publications and Presentations:

Publications have been submitted on this project: View all 2 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

Organ on a chip, neuronal development, organophosphates, metabolism, dose-response, toxins, pesticides, metabolomics.

Progress and Final Reports:

  • 2020 Progress Report
  • 2021 Progress Report