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Global gene expression analysis reveals dynamic and developmental stage-dependent enrichment of lead-induced neurological gene alterations.

Peterson SM, Zhang J, Weber G, Freeman JL - Environ. Health Perspect. (2010)

Bottom Line: This gene set was both confirmatory and novel in nature and was highly enriched for neurological development, function, and disease.Alternatively, the gene set at 120 hpf did not share association with neurological development.Gene expression alterations at the 72-hpf time point were highly enriched with genes and molecular pathways associated with neurological development and disease.

View Article: PubMed Central - PubMed

Affiliation: School of Health Sciences, Purdue University, West Lafayette, Indiana, USA.

ABSTRACT

Background: The underlying genetic mechanisms specific to subtle neurological alterations associated with environmental lead (Pb) exposures have not been clearly elucidated.

Objectives: The goal of this study was to identify novel gene targets and the underlying genetic mechanisms associated with developmental Pb neurotoxicity.

Methods: We first exposed zebrafish embryos to a range of Pb concentrations throughout early development to establish relative toxicity. Using the data from that experiment, we exposed another group of zebrafish embryos to a sublethal dose of Pb (100 ppb) immediately after fertilization through 72 or 120 hr postfertilization (hpf). Global gene expression was then analyzed for molecular pathways and gene ontology enrichment, and Western blot analysis was performed to investigate the translation of gene expression changes to protein levels.

Results: After 72 hpf, we identified 231 probes representing 90 nonredundant genes with well-established function or orthology to human genes as being altered by Pb exposure. This gene set was both confirmatory and novel in nature and was highly enriched for neurological development, function, and disease. Moreover, gene changes at this time point were correlated to altered protein levels. Alternatively, the gene set at 120 hpf did not share association with neurological development.

Conclusions: Global gene expression alterations associated with developmental Pb exposure were dynamic and dependent on developmental stage. Gene expression alterations at the 72-hpf time point were highly enriched with genes and molecular pathways associated with neurological development and disease. Moreover, we identified a number of novel targets for future exploration into their role in the genetic mechanisms underlying Pb-induced neurological alterations.

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Related in: MedlinePlus

Protein levels of four genes with altered expression at 72 hpf (MT2, FRYL, RELN, and MAPK8) as determined by Western blot analysis (A). Differences in protein levels of genes of interest in zebrafish embryos following exposure to 100 ppb Pb were compared with controls after being normalized to GAPDH (B). All blots are representative of results of three biological replicates. Protein levels of MT2 (B), FRYL (C), and RELN (D) were all altered in the Pb-treated embryos, whereas MAPK8 (E) did not demonstrate a significant alteration.*p ≤ 0.05, and **p ≤ 0.01.
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f4-ehp-119-615: Protein levels of four genes with altered expression at 72 hpf (MT2, FRYL, RELN, and MAPK8) as determined by Western blot analysis (A). Differences in protein levels of genes of interest in zebrafish embryos following exposure to 100 ppb Pb were compared with controls after being normalized to GAPDH (B). All blots are representative of results of three biological replicates. Protein levels of MT2 (B), FRYL (C), and RELN (D) were all altered in the Pb-treated embryos, whereas MAPK8 (E) did not demonstrate a significant alteration.*p ≤ 0.05, and **p ≤ 0.01.

Mentions: Using Western blot analysis, we measured relative changes in the protein levels of MT2, FRYL, RELN, and MAPK8. Significant alterations were present in MT2, RELN, and FRYL levels in Pb-treated samples, whereas MAPK8 appeared to be unchanged (Figure 4). The levels of MT2 protein increased to > 600% of control (p = 0.006). The antibody for RELN recognized multiple bands that correspond to the full-length protein as well as expected processed fragments. The levels of the unprocessed form were increased to 309% of control in the treated samples (p = 0.0425). FRYL protein was markedly decreased, as evidenced by two bands representing products of similar size (larger product: 63% of control, p = 0.047; smaller product: 57% of control, p = 0.016; combined: 60.2% of control, p = 0.020). MAPK8 protein levels did not significantly change with Pb treatment (p = 0.53).


Global gene expression analysis reveals dynamic and developmental stage-dependent enrichment of lead-induced neurological gene alterations.

Peterson SM, Zhang J, Weber G, Freeman JL - Environ. Health Perspect. (2010)

Protein levels of four genes with altered expression at 72 hpf (MT2, FRYL, RELN, and MAPK8) as determined by Western blot analysis (A). Differences in protein levels of genes of interest in zebrafish embryos following exposure to 100 ppb Pb were compared with controls after being normalized to GAPDH (B). All blots are representative of results of three biological replicates. Protein levels of MT2 (B), FRYL (C), and RELN (D) were all altered in the Pb-treated embryos, whereas MAPK8 (E) did not demonstrate a significant alteration.*p ≤ 0.05, and **p ≤ 0.01.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3094410&req=5

f4-ehp-119-615: Protein levels of four genes with altered expression at 72 hpf (MT2, FRYL, RELN, and MAPK8) as determined by Western blot analysis (A). Differences in protein levels of genes of interest in zebrafish embryos following exposure to 100 ppb Pb were compared with controls after being normalized to GAPDH (B). All blots are representative of results of three biological replicates. Protein levels of MT2 (B), FRYL (C), and RELN (D) were all altered in the Pb-treated embryos, whereas MAPK8 (E) did not demonstrate a significant alteration.*p ≤ 0.05, and **p ≤ 0.01.
Mentions: Using Western blot analysis, we measured relative changes in the protein levels of MT2, FRYL, RELN, and MAPK8. Significant alterations were present in MT2, RELN, and FRYL levels in Pb-treated samples, whereas MAPK8 appeared to be unchanged (Figure 4). The levels of MT2 protein increased to > 600% of control (p = 0.006). The antibody for RELN recognized multiple bands that correspond to the full-length protein as well as expected processed fragments. The levels of the unprocessed form were increased to 309% of control in the treated samples (p = 0.0425). FRYL protein was markedly decreased, as evidenced by two bands representing products of similar size (larger product: 63% of control, p = 0.047; smaller product: 57% of control, p = 0.016; combined: 60.2% of control, p = 0.020). MAPK8 protein levels did not significantly change with Pb treatment (p = 0.53).

Bottom Line: This gene set was both confirmatory and novel in nature and was highly enriched for neurological development, function, and disease.Alternatively, the gene set at 120 hpf did not share association with neurological development.Gene expression alterations at the 72-hpf time point were highly enriched with genes and molecular pathways associated with neurological development and disease.

View Article: PubMed Central - PubMed

Affiliation: School of Health Sciences, Purdue University, West Lafayette, Indiana, USA.

ABSTRACT

Background: The underlying genetic mechanisms specific to subtle neurological alterations associated with environmental lead (Pb) exposures have not been clearly elucidated.

Objectives: The goal of this study was to identify novel gene targets and the underlying genetic mechanisms associated with developmental Pb neurotoxicity.

Methods: We first exposed zebrafish embryos to a range of Pb concentrations throughout early development to establish relative toxicity. Using the data from that experiment, we exposed another group of zebrafish embryos to a sublethal dose of Pb (100 ppb) immediately after fertilization through 72 or 120 hr postfertilization (hpf). Global gene expression was then analyzed for molecular pathways and gene ontology enrichment, and Western blot analysis was performed to investigate the translation of gene expression changes to protein levels.

Results: After 72 hpf, we identified 231 probes representing 90 nonredundant genes with well-established function or orthology to human genes as being altered by Pb exposure. This gene set was both confirmatory and novel in nature and was highly enriched for neurological development, function, and disease. Moreover, gene changes at this time point were correlated to altered protein levels. Alternatively, the gene set at 120 hpf did not share association with neurological development.

Conclusions: Global gene expression alterations associated with developmental Pb exposure were dynamic and dependent on developmental stage. Gene expression alterations at the 72-hpf time point were highly enriched with genes and molecular pathways associated with neurological development and disease. Moreover, we identified a number of novel targets for future exploration into their role in the genetic mechanisms underlying Pb-induced neurological alterations.

Show MeSH
Related in: MedlinePlus