Grantee Research Project Results
2023 Progress Report: A Neurovascular Unit on Chip for Reducing Animals in Organophosphate Neurotoxicology
EPA Grant Number: R839504Title: A Neurovascular Unit on Chip for Reducing Animals in Organophosphate Neurotoxicology
Investigators: Cliffel, David , May, Jody , McLaughlin, BethAnn
Current Investigators: Cliffel, David , May, Jody , Neely, M. Diana
Institution: Vanderbilt University , Vanderbilt University Medical Center
EPA Project Officer: Callan, Richard
Project Period: August 1, 2019 through July 31, 2022 (Extended to July 31, 2024)
Project Period Covered by this Report: August 1, 2022 through 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
Objective:
We are developing an organ on a chip platform entitled the Neurovascular Unit on Chip (NVU) for neuronal development and toxicity studies that faithfully replicates the blood-brain barrier. This NVU is multicell type-based with dynamic metabolic and signaling methods of assessing chemical and drug toxicity without the limitations of animal studies or standard cell death/morphology toxicology assays. Our objective is to demonstrate that the NVU provides equal if not superior information than conventional animal toxicity assays for organophosphate compounds of interest like chlorpyrifos. We have developed the microclinical analyzer and cellular signaling assays to measure in situ both the acute and chronic responses of the multiple cell lines that recreate neuronal tissues to exposures to potential drugs and other chemicals. Our approach has the advantage providing quantitative information regarding a variety of cellular activities, including metabolism, membrane transport, protein translation, and hence provides a comprehensive approach to absorption, distribution, metabolism, excretion (ADME) and toxicological (TOX) profiles.
Progress Summary:
Over the years, we focused on the role of astrocytes in mediating the response to chlorpyrifos while trying multiple paths to humanized neurons responding to a controlled but varied array of neurotransmitters. Two different theories on the role of astrocytes in chlorpyrifos present in the literature were evaluated with our approach. In the biosensor development for this final year, we have address stability and lifetimes for the enzymatic biosensors while demonstrating solid contact ion selective electrodes for NVU use. Finally, we have worked to improve on the ex situ measurements of BBB membrane integrity and permeability experiments within the NVU by comparing different sources of endothelial cells using in situ transendothelial electrical resistance (TEER) measurements. These TEER measurements provide a direct measurement of the resistance of the BBB membrane, and thus can immediately identify any changes to the membrane permeability for small molecules like chlorpyrifos exposure.
Future Activities:
In the final extension year period, we will write up the astrocyte-chlorpyrifos studies. We are working to revise the manuscript the multiple neurotransmitter work from the first year, with some additional experiments requested after peer review. We will design and print a 3D printed TEER platform added to the NVU for future widespread use, and will have fully humanized the NVU tissues for future projects reducing any need for animal use in line with the goals for the EPA program. We will also work on publishing the neurotransmitter sensor paper, a TEER NVU paper, an astrocyte-neuron interaction paper with chlorpyrifos; all of which are sections in the results above. A final oral presentation will be given in February at the EPA STAR PI meeting.
Journal Articles:
No journal articles submitted with this report: View all 4 publications for this projectSupplemental Keywords:
Chlorpyrifos, Blood Brain Barrier, Neurovascular Unit, Microclinical Analyzer, MicrophysiometryProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.