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2006 Progress Report: Center for Children’s Environmental Health Research – Mechanisms of Pesticide Neuro- and Immunotoxicity
EPA Grant Number: R831710C003Subproject: this is subproject number 003 , established and managed by the Center Director under grant R831710
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: University of California Berkeley Center for Children’s Environmental Health Research
Center Director: Eskenazi, Brenda
Title: Center for Children’s Environmental Health Research – Mechanisms of Pesticide Neuro- and Immunotoxicity
Investigators: Holland, Nina T. , Casida, John , Lipsett, Michael , Tager, Ira
Institution: University of California - Berkeley
EPA Project Officer: Fields, Nigel
Project Period: May 1, 2004 through October 31, 2008 (Extended to October 31, 2010)
Project Period Covered by this Report: May 1, 2006 through October 31, 2007
RFA: Centers for Children's Environmental Health and Disease Prevention Research (2003)
Research Category: Health Effects , Children's Health
Description:
Objective:The Specific aims of this project are:
- To examine the in vitro effects of the organophospate (OP) pesticide chlorpyrifos, the carbamate maneb, dust mite allergen (Der p1), alone and in combination, on the production of Th1/Th2 cytokines.
- To determine whether pesticide and allergen exposures differentially affect in vitro cytokine expression in lymphocytes of children versus those of adults.
- To establish a mechanism-based new enzymatic assay for “neuropathy target esterase” (NTE) in human adult lymphocytes and neuroblastoma cell line.
- To determine the ontogenetic changes in NTE activity in human fetus, child and adult.
- To determine the sensitivity of NTE in fetal and adult lymphocytes to known NTE inhibitors and to test the relative sensitivity of NTE and AChE to these inhibitors.
- To determine the sensitivity of NTE in fetal versus adult lymphocytes to widely used pesticides in their bioactivated form.
Specific Aims 1 and 2: Immunotoxicity of pesticides and allergens:
We previously developed and validated a method to measure induction of intracellular cytokines in small quantities of blood (Duramad et al. 2004). This year, we published the first paper applying this method in CHAMACOS 24-month olds. We found that asthma, maternal work in the fields, and gas stoves in the home were associated with increased Th2, and longer breastfeeding was associated with an increase in Th1 (Duramad et al., 2006 EHP). Using this methodology we also analyzed cytokine profiles in blood from 270 CHAMACOS 5-year-olds. We observed an increased variability in intracellular cytokines in older children in comparison with CHAMACOS neonates and 24-month old children. Overall levels of Th1 increased and Th2 decreased with age. No statistically significant sex differences were identified.
We also conducted in vitro studies where human cells were treated with OPs in combination with endotoxin and allergens. We found that combined treatment with both endotoxin and CPO produced a response greater than endotoxin alone, whereas OPs (chlopyrifos and two metabolites) alone did not induce cytokines (Duramad et al., 2006, J of Applied Tox).
Specific Aims 3-6: Neurotoxicity of pesticides
A new radioactive NTE-lysophospholipase assay was developed and validated against the colorimetric lysolecithin NTE assay. The new assay has improved sensitivity and is suitable for use with small volumes of biological samples. The colorimetric NTE assay was performed with 270 μg of mouse brain homogenate, while the new NTE assay operates with only 169 μg of homogenate. The new radioactive assay requires only 25 μg of lymphocyte protein and 500 μg of erythrocyte protein. A great advantage of the new assay is that it does not rely on a color change to detect activity, thus allowing the measurement of activity with the background red color of erythrocytes.
Progress was made on characterization of two previously identified OP-sensitive enzymes hypothesized to be related to neurotoxic target esterase (NTE). Biochemically, one was recently identified as a lysophospholipase (lysoPLA) based on substrate and inhibitor specificity and designated NTE-lysoPLA. LysoPLA activities of human erythrocytes and lymphocytes were shown essentially identical in OP sensitivity, and comparable to the mouse brain LysoPLA (Table 6). NTE and LysoPLA of mouse brain were highly correlated, but NTE was 5-8X more OP-sensitive.
To further explore potential similarity between NTE and lysoPLA, three pooled batches of maternal and child bloods were created, each containing between 8 and 14 samples. They were used to study effects of known inhibitors of NTE. Those proved to be very potent on lysoPLA of lymphocytes and erythrocytes, with IC50s < 1 nM for S-OBDPO, IDFP and EOPF. Of the seven pesticides or activated metabolites tested, only CPO and diazoxon were potent at less than 100 μM toward LysoPLA in adult human cells. Currently, the identification of enzymes contributing to lysoPLA activity in erythrocytes and lymphocytes is underway using radiolabelling and specific antibody quantification. This work is part of the dissertation research for Sarah Owen, PhD candidate.
Other activities: PON1 (see Laboratory Core for more details)
Results of initial analyses of PON1 genotype and enzymatic activity for 130 mother-child CHAMACOS pairs have been published this year (Holland et al., 2006; Furlong, Holland et al., 2006). These preliminary data allowed us to secure additional funding this year (Holland PI NIEHS RO1; Eskenazi PI EPA Star) to expand the study of the functional genomics of paraoxonase in all CHAMACOS mothers and children, and to establish PON1 effects on growth and neurodevelopment in exposed children.
We plan to explore the role of exposure and host factors in modifying OP effects on neurotoxicity and immunotoxicity in CHAMACOS children. This will be supported by in vitro studies of the effects of combined OPs in different age and gender groups.
Journal Articles on this Report : 8 Displayed | Download in RIS Format
| Other subproject views: | All 25 publications | 16 publications in selected types | All 14 journal articles |
| Other center views: | All 119 publications | 72 publications in selected types | All 69 journal articles |
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Duramad P, Harley K, Lipsett M, Bradman A, Eskenazi B, Holland NT, Tager IB. Early environmental exposures and intracellular Th1/Th2 cytokine profiles in 24-month-old children living in an agricultural area. Environmental Health Perspectives 2006;114(12):1916-1922. |
R831710 (2005) R831710C001 (2006) R831710C001 (2007) R831710C002 (2006) R831710C003 (2006) R831710C003 (2007) |
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Duramad P, Tager IB, Leikauf J, Eskenazi B, Holland NT. Expression of Th1/Th2 cytokines in human blood after in vitro treatment with chlorpyrifos, and its metabolites, in combination with endotoxin LPS and allergen Der p1. Journal of Applied Toxicology2006;26(5):458-465. |
R831710 (2005) R831710C003 (2006) |
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Furlong CE, Holland N, Richter RJ, Bradman A, Ho A, Eskenazi B. PON1 status of farmworker mothers and children as a predictor of organophosphate sensitivity. Pharmacogenetics and Genomics 2006;16(3):183-190. |
R831710 (2004) R831710 (2005) R831710C001 (2007) R831710C003 (2006) R831710C003 (2007) R831709 (2005) R831709 (2006) R831709C002 (2006) |
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Holland N, Furlong C, Bastaki M, Richter R, Bradman A, Huen K, Beckman K, Eskenazi B. Paraoxonase polymorphisms, haplotypes, and enzyme activity in Latino mothers and newborns. Environmental Health Perspectives 2006;114(7):985-991. |
R831710 (2004) R831710 (2005) R831710C001 (2007) R831710C003 (2006) R831709 (2005) R831709 (2006) R831709C002 (2006) R832734 (2006) |
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Neri M, Bonassi S, Knudsen LE, Sram RJ, Holland N, Ugolini D, Merlo DF. Children’s exposure to environmental pollutants and biomarkers of genetic damage. I. Overview and critical issues. Mutation Research 2006;612(1):1-13. |
R831710C003 (2006) R832734 (2006) |
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Neri M, Ugolini D, Bonassi S, Fucic A, Holland N, Knudsen LE, Sram RJ, Ceppi M, Bocchini V, Merlo DF. Children’s exposure to environmental pollutants and biomarkers of genetic damage. II. Results of a comprehensive literature search and meta-analysis. Mutation research 2006;612(1):14-39. |
R831710C003 (2006) R832734 (2006) |
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Quistad GB, Liang SN, Fisher KJ, Nomura DK, Casida JE. Each lipase has a unique sensitivity profile for organophosphorus inhibitors. Toxicological Sciences 2006;91(1):166-172. |
R831710C003 (2006) |
not available |
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Quistad GB, Klintenberg R, Caboni P, Liang SN, Casida JE. Monoacylglycerol lipase inhibition by organophosphorus compounds leads to elevation of brain 2-arachidonoylglycerol and the associated hypomotility in mice. Toxicology and Applied Pharmacology 2006;211(1):78-83. |
R831710C003 (2006) |
not available |
organophosphate, carbamate, allergen, pesticides, neuropathy target esterase, NTE, cytokines,
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ENVIRONMENTAL MANAGEMENT, Scientific Discipline, Health, RFA, PESTICIDES, Risk Assessment, Health Risk Assessment, Children's Health, Pesticide Types, exposure assessment, insecticides, allergen, health effects, respiratory problems, children's environmental health, assessment of exposure, childhood respiratory disease, outreach and education, agricultural community, community-based intervention, pesticide exposure, airway disease, environmental risks, immune system effects, environmental health hazard
Relevant Websites:
Progress and Final Reports:
2004 Progress Report
2005 Progress Report
Original Abstract
2007 Progress Report
Main Center Abstract and Reports:
R831710 University of California Berkeley Center for Children’s Environmental Health Research
Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R831710C001 Center for Children’s Environmental Health Research – CHAMACOS Community Based Research Project
R831710C002 Center for Children’s Environmental Health Research – Pesticide Exposure Assessment Project
R831710C003 Center for Children’s Environmental Health Research – Mechanisms of Pesticide Neuro- and Immunotoxicity
R831710C004 Center for Children’s Environmental Health Research – Community Outreach and Translation Core