Transcriptome analysis of different sizes of 3-mercaptopropionic acid-modified cadmium telluride quantum dot-induced toxic effects reveals immune response in rat hippocampus

J Appl Toxicol. 2018 Sep;38(9):1177-1194. doi: 10.1002/jat.3629. Epub 2018 May 3.

Abstract

Recently, the increasing number of bio-safety assessments on cadmium-containing quantum dots (QDs) suggested that they could lead to detrimental effects on the central nervous system (CNS) of living organisms, but the underlying action mechanisms are still rarely reported. In this study, whole-transcriptome sequencing was performed to analyze the changes in genome-wide gene expression pattern of rat hippocampus after treatments of cadmium telluride (CdTe) QDs with two sizes to understand better the mechanisms of CdTe QDs causing toxic effects in the CNS. We identified 2095 differentially expressed genes (DEGs). Fifty-five DEGs were between the control and 2.2 nm CdTe QDs, 1180 were between the control and 3.5 nm CdTe QDs and 860 were between the two kinds of CdTe QDs. It seemed that the 3.5 nm CdTe QD exposure might elicit severe effects in the rat hippocampus than 2.2 nm CdTe QDs at the transcriptome level. After bioinformatics analysis, we found that most DEG-enriched Gene Ontology subcategories and Kyoto Encyclopedia of Genes and Genomes pathways were related with the immune system process. For example, the Gene Ontology subcategories included immune response, inflammatory response and T-cell proliferation; Kyoto Encyclopedia of Genes and Genomes pathways included NOD/Toll-like receptor signaling pathway, nuclear factor-κB signaling pathway, tumor necrosis factor signaling pathway, natural killer cell-mediated cytotoxicity and T/B-cell receptor signaling pathway. The traditional toxicological examinations confirmed the systemic immune response and CNS inflammation in rats exposed to CdTe QDs. This transcriptome analysis not only revealed the probably molecular mechanisms of CdTe QDs causing neurotoxicity, but also provided references for the further related studies.

Keywords: central nervous system; immune response; inflammation; quantum dot; transcriptome sequencing.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Mercaptopropionic Acid / analogs & derivatives
  • 3-Mercaptopropionic Acid / toxicity*
  • Animals
  • Cadmium Compounds / toxicity*
  • Databases, Genetic
  • Gene Expression Profiling / methods*
  • Gene Regulatory Networks / drug effects
  • Hippocampus / drug effects*
  • Hippocampus / immunology
  • Hippocampus / metabolism
  • Immunity / drug effects*
  • Immunity / genetics
  • Male
  • Particle Size
  • Quantum Dots / toxicity*
  • Rats, Wistar
  • Tellurium / toxicity*
  • Transcriptome / drug effects*

Substances

  • Cadmium Compounds
  • 3-Mercaptopropionic Acid
  • Tellurium
  • cadmium telluride