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Your Environment. Your Health.

Molecular Toxicology & Genomics Group

B. Alex Merrick, Ph.D.
B A. Merrick, Ph.D.
Molecular Toxicologist, Group Leader
Tel 984-287-3161
P.O. Box 12233
Mail Drop K2-17
Durham, N.C. 27709
Molecular Toxicology and Genomics Group

Research Summary

The Molecular Toxicology and Genomics Group, headed by B. Alex Merrick, Ph.D., uses advanced technologies and computational approaches to relate chemicals to genes, genes to pathways, and pathways to disease. Development of toxicity signatures will further our understanding of disease processes and contribute to predictive models of toxicity and chemical prioritization. In addition, next generation (NextGen) sequencing is being used to study the relationship of genomic and epigenomic structure to gene expression and chemical toxicity.

Major Areas of Research

  • Identify molecular mechanisms of toxicity action and disease-associated pathways by gene and reporter expression analysis.
  • Develop computational and predictive models for animal and human biological response to environmental toxicants.
  • Prioritize substances for further in-depth toxicological evaluation.

Current Projects

  • Toxicity signatures – Toxicogenomic screening by microarrays and RNA-Seq are being used for in vitro and in vivo chemical exposures to derive patterns of gene expression and novel transcripts for predicting disease (e.g., tumor formation) and target organ toxicity.
  • NextGen Sequencing – Transcriptomic profiles can be generated with base pair resolution with opportunities for new transcript discovery.
  • Mouse Methylome – The Mouse Methylome Project is a DIR/DNTP collaboration to determine DNA methylation patterns by whole genome bisulfite sequencing. DNA methylation patterns can be related to transcript expression in different mouse strains with variable susceptibility to liver tumors.
  • Archival tissue gene expression – Studies are being conducted to evaluate new technologies (e.g., NextGen sequencing) for retrospectively interrogating changes in DNA sequence/methylation patterns and/or RNA expression, using fresh frozen and formalin-fixed, paraffin embedded tissues from animal studies that are stored in the National Toxicology Program (NTP) tissue archives.
  • Endocrine active compounds – Compounds exhibiting endocrine activity in qHTS assays are being evaluated in additional assays for biological relevance.

B. Alex Merrick, Ph.D. is a Molecular Toxicologist who joined the NTP Biomolecular Screening Branch (BSB) in 2010. Merrick leads the Branch's Molecular Toxicology and Genomics Group. His responsibilities include identifying key signaling pathways and transcripts altered by environmental toxicants and participating in the Tox21 collaboration between the NTP, the NIH Chemical Genomics Center (NCGC), the Environmental Protection Agency's National Center for Computational Toxicology (NCCT) and the Food and Drug Administration (FDA). He is especially interested in performing molecular analysis in NTP archival tissues to discover gene expression and epigenetic signatures from chemical toxicology studies. Collaborative work with the Cellular and Molecular Pathology Branch aims to use NTP archival research to further pathological insight, better understand mechanisms of chemical toxicity and contribute to predictive models of toxicity and chemical prioritization as a complementary effort to the Tox21 high throughput screening program. In addition, NextGen sequencing projects will help NTP better evaluate chemically exposed tissues for differential transcript profiles that include splice variants, low copy transcripts and non-coding mRNA's.

Before joining the Biomolecular Screening Branch, Merrick was head of the Proteomics Group within the Division of Intramural Research's (DIR) National Center for Toxicogenomics. His group performed protein and gene expression profiling of hepatoxic agents to identify mechanisms of liver injury, with special interest in p53 biology.

Merrick received his Ph.D. in 1984 at the University of Nebraska Medical Center in Omaha, performing post-doctoral work in the Biology Division at Oak Ridge National Laboratory. He headed the Hepatotoxicology section at the US EPA in Cincinnati, OH from 1985 to 1988 before joining NIEHS in 1989. He currently serves as an adjunct Associate Professor in the Department of Environmental and Molecular Toxicology at NC State University.

Recent Publications

  1. Merrick BA, Chang JS, Bostrom MA, Phadke DP, Shah RR, Wang X, Gordon O and Wright, GM. (2018). HAfTs are novel lncRNA transcripts from aflatoxin exposure. PLoS One. 13(1): e0190992, 1-25. [Abstract] 
  2. Li R, Grimm SA, Mav D, Gu H, Djukovic D, Shah R, Merrick BA, Raftery D and Wade PA. (2018). Epigenetic memory of obesity predisposes to colorectal cancer. Cell Reports. 22(3): 624-637. [Abstract] 
  3. Duncan CG, Kondilis-Mangum HD, Grimm SA, Bushel P, Chrysovergis K, Roberts JD, Tyson F, Merrick BA and Wade P. (2018). Base-resolution analysis of DNA methylation patterns downstream of Dnmt3a in mouse naïve B cells. 3G: Genes|Genomes|Genetics. [Abstract] 
  4. Lynch C, Zhao J, Huang R, Kanaya N, Bernal L, Hsieh JH, Auerbach SS, Witt KL, Merrick BA, Chen S, Teng CT and Xia M. (2017). Identification of Estrogen-Related Receptor Alpha Agonists in the Tox21 Compound Library. Endocrinology. 159(2):744-753. [Abstract] 
  5. Teng CT, Hsieh J-H, Zhao J, Huang R, Xia M, Martin N, Gao X, Dixon D, Auerbach SS, Witt KL Merrick BA. (2017). Development of novel cell lines for high throughput screening to detect estrogen- related receptor alpha modulators. SLAS Discovery. 22:720-731. [Abstract] 
  6. Dunnick JK, Morgan DL, Elmore S, Gerrish K, Pandiri A, Ton TV, Shockley KR and Merrick BA. (2017). Tetrabromobisphenol A activates the hepatic interferon pathways in rats. Toxicol Lett. 266:32-41. [Abstract] 
  7. Dunnick JK, Merrick BA, Brix A, Morgan DL, Gerrish K, Wang Y, Flake G, Foley J, Shockley KR. (2016). Molecular changes in the nasal cavity after N,N-Dimethyl-p-toluidine exposure. Toxicologic Pathology 44(6):835-847. [Abstract]
  8. Merrick BA, Paules RS and Tice RR. Intersection of Toxicogenomics and High Throughput Screening in the Tox21 Program. (2015). An NIEHS Perspective. Int. J. Biotechnology 14(1):7-27. [Abstract]
  9. Pelch KE, Tokar EJ, Merrick BA, and Waalkes MP. (2015). Differential DNA methylation profile of key genes in malignant prostate epithelial cells transformed by inorganic arsenic or cadmium. Toxicol Appl Pharmacol. 286:159-167. [Abstract]
  10. Morgan D, Merrick BA, Gerrish KE, Stockton PS, Foley JF, Wang Y, Gwinn WM, Kelly FF, Palmer SM, Ton T-V T, Hoenerhoff JJ and Flake GP. (2015). Gene expression of obliterative bronchiolitis-like lesions in 2,3-pentanedione-exposed rats. PLoS One. 10(2):e0118459. [Abstract]
  11. Auerbach SS, Phadke D, Mav D, Gao Y, Xie B, Shin JH, Shah RR, Merrick BA, Tice RR. (2015). RNA-Seq-based Toxicogenomic Assessment of Fresh Frozen and Formalin Fixed Tissues Yields Similar Mechanistic Insights. J Appl Toxicol. 35:766-780. [Abstract]
  12. Merrick BA, Phadke DP, Auerbach SS, Mav D, Stiegelmeyer SM, Shah RR, Tice RR. (2013). RNA-Seq profiling reveals novel hepatic gene expression pattern in aflatoxin B1 treated rats. PLoS One. 8(4):e61768-. [Abstract]
  13. Merrick BA, Auerbach SS, Stockton PS, Foley JF, Malarkey DE, Sills RC, Irwin RD and Tice RR. (2012). Testing an aflatoxin B1 gene signature in rat archival tissues. Chem Res Toxicol. 25:1132-1144. [Abstract]
  14. Merrick BA, London RE, Bushel PR, Grissom SF and Paules RS. (2011). Platforms for biomarker analysis using high-throughput approaches in genomics, transcriptomics, proteomics, metabolomics and bioinformatics. IARC Sci Publ. 163:121-142. [Abstract]
  15. Merrick BA, Dhungana S, Williams JG, Aloor JJ, Peddada S, Tomer KB and Fessler MB. (2011). Proteomic profiling of S-acylated macrophage proteins identifies a role for palmitoylation in mitochondrial targeting of phospholipid scramblase 3. Molec Cellular Proteomics. M110.00607-13. [Abstract]
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