Source: MISSISSIPPI STATE UNIV submitted to NRP
BIOCHEMICAL TOXICOLOGY OF AGROCHEMICAL ORGANOPHOSPHATES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0232818
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Nov 1, 2012
Project End Date
Oct 31, 2017
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
MISSISSIPPI STATE UNIV
(N/A)
MISSISSIPPI STATE,MS 39762
Performing Department
Entomology & Plant Pathology
Non Technical Summary
Organophosphate (OP) compounds are one of the most widely used insecticides in the world, however exposure and toxicity can pose a hazard to farm workers. Research in the Chambers' Lab in cooperation with the College of Veterinary Medicine has yielded several new potential antidotes for organophosphates that reach the brain and, in part, reverse the initial toxic effects. This research is of paramount important to the development of methods to mitigate overexposure incidences in farm workers, and in the development of new agrochemicals with novel mechanisms of action against insects and other crop pests.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
7235220115050%
3145220115050%
Knowledge Area
314 - Toxic Chemicals, Poisonous Plants, Naturally Occurring Toxins, and Other Hazards Affecting Animals; 723 - Hazards to Human Health and Safety;

Subject Of Investigation
5220 - Pesticides;

Field Of Science
1150 - Toxicology;
Goals / Objectives
Organophosphate (OP) compounds are one of the most widely used insecticides in the world, however exposure and toxicity can pose a hazard to farm workers. Research in the Chambers' Lab in cooperation with the College of Veterinary Medicine has yielded several new potential antidotes for organophosphates that reach the brain and, in part, reverse the initial toxic effects. In addition, many of these agents or their surrogates/metabolites, have been re-converted to commercial insecticides or other agrochemicals. The Objectives of this study are to examine: (1) Acetylcholinesterase (ACHE) Re-activators: Synthesis of oximes as potential organophosphate (OP) antidotes will be continued, and further research on promising existing compounds will be conducted; and (2) Paraoxonase Activation: The potential ability of exogenous nucleophilic chemicals to enhance the rate at which paraoxonase (PON) degrades OP's will be investigated. As such, the susceptibility to pesticides may be modified by altering enzymes, such as paraoxonase, that play a significant role in metabolizing organophosphates. The outcomes from these studies range from the development of protective or detoxifying compounds in farm worker overexposure incidences, to the development of new agrochemicals with novel mechanisms of action.
Project Methods
Standard chemical reactive assays will be employed, along with chemical purification methodologies using crystallization techniques. Specific compounds to be guided will be done so using structure-activity relationships of existing compounds. Again, final products will be purified by recrystallization and structures confirmed by mass spectrometry. For assays of acetylcholinesterase (ACHE)reactivation, initial assays will be conducted using a bovine brain ACHE assay. This enzyme was chosen because tissue is readily available locally and enzyme activity of frozen tissue or homogenates thereof is stable for up to one year. Reactivation will be determined as the decrease in observed inhibition following incubation with oximes. This procedure has been used successfully in the Chambers lab for more than five years. Subsequent in vivo studies will be conducted at CVM by Dr. Janice Chambers' research group. For enhancement of Paraoxonase, assays will use methodologies similar to that for reactivation. Selection of nucleophiles and other chemicals for testing (osimes and hydrazones) will be guided by molecular modeling studies performed in the Chemistry Department (Dr. Steve Gwaltney).

Progress 11/01/12 to 10/31/17

Outputs
Target Audience:Pesticide manufacturers, applicators and users, as well as military personnel and the general public as potential targets of terrorist attack. Changes/Problems:Further work on this project ended in December 2016 when the Principle Investigator passed away. What opportunities for training and professional development has the project provided?This project did not employee students or other trainees. A research technician engaged in the research retired after the Principal Investigator passed away and the project ended. How have the results been disseminated to communities of interest?Results from this work were reported through peer-reviewed publications and presentations at relevant scientific conferences. What do you plan to do during the next reporting period to accomplish the goals?The project has ended and there are no plans to renew or extend the project.

Impacts
What was accomplished under these goals? Ten potential prophylactic agents for organophosphate toxicants were synthesized and tested. Six new oxime compounds were found to enhance the activity of paraoxonase in hydrolyzing several organophospates in vitro (rat and human serum). Five selected for further screening showed promise in vitro as potential antidotes for organophosphate (OP) poisoning and were tested in in vivo assays. They were shown to be equal or superior to 2-PAM in preventing lethal effects of two OP's tested. Three were found to be superior to existing antidotes against two OP's. These experimental antidotes prevented or shortened the duration of seizures associated with long-term brain damage, but observed increases were generally less than 2-fold and potential value as prophylactic antidotes is doubtful. 2-PAM had no effect on seizures.

Publications


    Progress 10/01/15 to 09/30/16

    Outputs
    Target Audience:Pesticide manufacturers, applicators and users, and, general public as potential targets of terrorist attack. Changes/Problems:No significant problems have been encountered and no significant changes are planned for the next year. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Through journals and professional presentations. What do you plan to do during the next reporting period to accomplish the goals?All previous studies reported have been with rats. Most promising antidotes will be tested in guinea pigs, the more widely accepted animal model.

    Impacts
    What was accomplished under these goals? Five experimental antidotes were found to be equal or superior to 2-PAM in preventing lethal effects of two OP's tested. In addition, experimental antidotes prevented or shortened the duration of seizures associated with long-term brain damage. 2-PAM had no effect on seizures.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Carr, R.L., M.B. Dail, H.W. Chambers and J.E. Chambers. 2015. Species differences in paraoxonase mediated hydrolysis of several organophosphorus insecticide metabolites. J Toxicol. 2015:470189. http://dx.doi.org/1 0.1155/2015/470189. PMID: 25784934.
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Meek, E.C. H.W. Chambers, R.B. Pringle and J.E. Chambers. 2015. The effect ofPON1 enhancers on reducing acetylcholinesterase inhibition following organophosphate anticholinesterase exposure in rats. Toxicology. 336:79-83. PMID: 26275814.
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Chambers J.E., E.C. Meek, J.P. Bennett, W.S. Bennett, H.W. Chambers, C.A. Leach, R.B. Pringle and R.W. Wills. 2015. Novel substituted phenoxyalkyl pyridinium oximes enhance survival and attenuate seizure-like behavior ofrats receiving lethal levels of nerve agent surrogates. Toxicology. 339:51-57. PMID: 26705700.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Caban, A., R.L. Carr H.W. Chanibers, K.O. Willeford and J.E. Chambers. 2016. Comparison of inhibition kinetics of several organophosphates, including some nerve agent surrogates, using human erythrocyte and rat and mouse brain acetylcholinesterase. Toxicol. Lett. 248:39-45. PMID: 26965078.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Chambers J.E., E.C. Meek and H.W. Chambers. 2016. Novel brain-penetrating oximes for reactivation of acetylcholinesterase inhibited by sarin and VX surrogates. Ann. NY Acad. Sci. 1374:52-58. PMID: 27153507.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Chambers J.E., H.W. Chambers, K.E. Funck, E.C. Meek, R.B. Pringle and M.K. Ross. 2016. Efficacy of novel phenoxyalkyl pyridinium oximes as brain-penetrating reactivators of cholinesterase inhibited by SlU'rogates of sarin and VX. Chemico-Biol. Interact. doi: 10.1016/j.cbi.2016.07.004. In press. PMID: 27387540.


    Progress 10/01/14 to 09/30/15

    Outputs
    Target Audience:General public as potential victims of terrorist attack with chemical warfare agents. Members of the Military. Changes/Problems:No significant problems have been encountered as yet and no changes are planned during the next year. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Through Journals and Professional Presentations What do you plan to do during the next reporting period to accomplish the goals?Continue research as described under major goals

    Impacts
    What was accomplished under these goals? Five oximes which showed promise in vitro as potential antidotes for organophosphate (OP) poisoning were moved to in vivo assays. Three were found to be superior to existing antidotes against two OP's. Six oximes were found to enhance paraoxonase activity in vitro against four OP's. Observed increases were generally less than 2-fold and potential value as prophylactic antidotes is doubtful.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Chambers, J.E., H.W. Chambers, E.C. Meek, K.E. Funck, M. Bhavaraju, S.R. Gwaltney and R.B. Pringle. 2015. Novel nucleophiles enhance the human serum paraoxonase 1 (PON1)-mediated detoxication of organophosphates. Toxicol.Sci. 143(1):46-53. PMID: 25304213
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Carr, R.L., M.B. Dail, H.W. Chambers and J.E. Chambers. 2015. Species differences in paraoxonase mediated hydrolysis of several organophorsphorus insecticide metabolites. J. Toxicol. 2015:470189. http://dx.doi.org/10.1155/2015/470189. PMID: 25784934
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Meek, E.C., H.W. Chambers, R.B. Pringle and J.E. Chambers. 2015. The effect of PON1 enhancers on reducing acetylcholinesterase inhibition following organophosphate anticholinesterase exposure in rate. Toxicology. 336. 336:79-83. PMID: 26275814
    • Type: Journal Articles Status: Submitted Year Published: 2015 Citation: Chambers, J.E., E.C. Meek, J.P. Bennett, W.S. Bennett, H.W. Chambers, C.A. Leach, R.B. Pringle and R.W. Wills. 2015. Novel substituted phenoxyalkyl pyridinium oximes enhance survival and attenuate seizure-like behavior of rats receiving lethal levels of nerve agent surrogates. Toxicology.
    • Type: Journal Articles Status: Submitted Year Published: 2015 Citation: Coban, A., R.L. Carr, H.W. Chambers, K.O. Willeford and J.E. Chambers. 2015. Comparison of inhibition kinetics of several organophosphates, including some nerve agent surrogates, using human erythrocyte and rat and mouse brain acetylcholinesterase. Arch. Toxicol.
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Dail, M.B., E.C. Meek, H.W. Chambers and J.E. Chambers. 2015. In vivo efficacy of novel oxime acetylcholinesterase reactivators is not completely explained by p-glycoprotein affinity. Toxicologist. 144:444. Presented: 54th Annual Meeting of the Society of Toxicology, San Diego, CA.
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Meek, E.C., R. Pringle, H.W. Chambers and J.E. Chambers. 2015. Novel nucleophiles as enhancers of detoxication of nerve agent surrogates by serum paraoxonase 1(PON1). Toxicologist. 144:445. Presented: 54th Annual Meeting of the Society of Toxicology, San Diego, CA.
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Pringle, R., E.C. Meek, H.W. Chambers and J.E. Chambers. 2015. Novel pyridinium oxime reactivators of organophosphate-inhibited acetylcholinesterase afford neural protection in the central nervous system. Toxicologist. 144:445. Presented: 54th Annual Meeting of the Society of Toxicology, San Diego, CA.
    • Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2015 Citation: Chambers, J.E., E.C. Meek, R.B. Pringle, H.W. Chambers and S.R. Gwaltney. 2015. Enhancement of degradation of nerve agent surrogates by human serum paraoxonase 1(PON1) by novel nucleophiles. Presented: Chemical and Biological Defense Science and Technology Conference, St. Louis, MO.


    Progress 10/01/13 to 09/30/14

    Outputs
    Target Audience: General public as potential victims of terrorist attack with chemical warfare agents. Members of the Military. Changes/Problems: No significant problems have been encountered as yet and no changes are planned during the next year. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Through Journals and Professional Presentations What do you plan to do during the next reporting period to accomplish the goals? Continue research as described under major goals

    Impacts
    What was accomplished under these goals? Research and development of previously synthesized potential nerve agent antidotes was continued. Five chemicals were selected for increased screening. Ten potential prophylactic agents for organophosphate toxicants were synthesized. Preliminary testing was initiated.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2014 Citation: McDaniel, C.Y., M.B. Dail, R.W. Wills, H.W. Chambers and J.E. Chambers. 2014.Paraoxonase 1 polymorphisms within a Mississippi USA population as possible biomarkers of enzyme activities associated with disease susceptibility. Biochem. Genet. In press. PMID: 25027835
    • Type: Journal Articles Status: Published Year Published: 2014 Citation: Coombes, R.H., E.C. Meek, M.B. Dail, H.W. Chambers and M.E. Chambers. 2014. Human paraoxonase 1 hydrolysis of nanomolar chlorpyrifos-oxon concentrations is unaffected by phenotype or Q192R genotype. Toxicol.Lett. 230:57-61. PMID: 25093614
    • Type: Journal Articles Status: Published Year Published: 2014 Citation: Chambers, J.E., H.W. Chambers, E.C. Meek, K.E. Funck, M. Bhavaraju, S.R. Gwaltney and R.B. Pringle. 2014. Novel nucleophiles enhance the human serum paraoxonase 1 (PON1) - mediated detoxication of organophosphates. Toxicol.Sci. doi: 10.1093/toxsci/kfu205. In press.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Pringle, R., E.C. Meek, H.W. Chambers, J.M. Gearhart and J.E. Chambers. 2014 Neural protection demonstrated in the central nervous system by novel pyridinium oxime reactivators of organophosphate-inhibited acetylcholinesterase. Toxicologist. 138(1):145. Presented: 53rd Annual meeting of the Society of Toxicology, Phoenix, AZ.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Chambers, J.E., E.C. Meek, R. Pringle and H.W. Chambers. 2014. Paraoxonase 1 (PON1) enhancers accelerate the detoxication of organophosphates (OP) including nerve agent surrogates. Toxicologist. 138(1):148. Presented: 53rd Annual meeting of the Society of Toxicology, Phoenix, AZ.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Meek E., R. Pringle, H. Chambers, J. Gearhart and J. Chambers. 2014. Novel centrally active oximes that reactivate organophosphate(OP) inhibited acetylcholinesterase (AChE) and demonstrate neural protection in rats. Presented: 19th Biennial US Army Medical Defense Bioscience Review, Hunt Valley, MD.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Chambers, J.E., E.C. Meek, R.B. Pringle and H.W. Chambers. 2014. Nucleophilic enhancers of detoxication of sarin and VX sunogates by serum paraoxonase 1 (PON1). Presented: 191h Biennial US Army Medical Defense Bioscience Review, Hunt Valley, MD.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Chambers, J.E., E. Meek, R Pringle, H. Chambers and S. Gwaltney. 2014. Nucleophiles enhance OP degradation by PON1. Presented: Chemical and Biological Defense Program's Enzyme Colloquium and Program Review, Falls Church, VA.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Chambers,J.E., E.C. Meek, R.B. Pringle and H.W. Chambers. 2014. Novel oxime nucleophiles enhance paraoxonase 1 (PONl)-mediated detoxication of organophosphate anticholinesterases. Presented: 19th North American ISSX (International Society for the Study of Xenobiotics) Meeting, San Francisco, CA.


    Progress 11/01/12 to 09/30/13

    Outputs
    Target Audience: Military personnel: Possible exposure to chemical warfare agents Agricultural workers: Possible exposure to organophosphate insecticides General public: Possible victims of terrorist activity Changes/Problems: No changes are anticipated. Future synthesis will be guided by current results and molecular modelling. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Continue initial goals as originally stated.

    Impacts
    What was accomplished under these goals? Six new oximes have been found to enhance the activity of paraoxonase in hydrolyzing several organophospates in vitro (rat and human serum). In vivo tests are pending.

    Publications