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Overcoming qRT-PCR interference by select carbon nanotubes in assessments of gene expression.

ABSTRACT: Nanomaterials (NMs) of various types, including carbon nanotubes (CNTs), can interfere with standard quantitative real-time PCR (qRT-PCR) assays, resulting in inaccurate gene expression measurements; however, the precise step in the qRT-PCR pipeline where this interference occurs has not been well described. Here, we investigated where in the process surface-oxidized multi-walled CNTs (oxMWNTs) inhibited qRT-PCR measurement of the expression of the housekeeping gene GAPDH and explored several strategies to minimize such inhibition. We determined that the interference occurred during the reverse transcription (RT) step and found that doubling reaction reagents or adding BSA successfully mitigated the inhibition. We observed assay interference in the presence of CNTs that were surface-oxidized, but pristine CNTs did not cause the same level of interference. These results highlight the importance of monitoring qRT-PCR assays for interference by CNTs that differ by surface chemistry, as these NMs are commonly used in gene expression assays at concentrations that we have shown to be inhibitory.

SUBMITTER: Humes ST

PROVIDER: S-EPMC6260796 | biostudies-other | 2017 Aug

REPOSITORIES: biostudies-other

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Overcoming qRT-PCR interference by select carbon nanotubes in assessments of gene expression.

Humes Sara T ST Hentschel Shannon S Lavelle Candice M CM Smith L Cody LC Lednicky John A JA Saleh Navid B NB Sabo-Attwood Tara T

BioTechniques 20170801 2

Nanomaterials (NMs) of various types, including carbon nanotubes (CNTs), can interfere with standard quantitative real-time PCR (qRT-PCR) assays, resulting in inaccurate gene expression measurements; however, the precise step in the qRT-PCR pipeline where this interference occurs has not been well described. Here, we investigated where in the process surface-oxidized multi-walled CNTs (oxMWNTs) inhibited qRT-PCR measurement of the expression of the housekeeping gene GAPDH and explored several st ...[more]

PMID: 28803544

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Project description:Multi-walled carbon nanotubes (MWCNTs) are among the most promising nanomaterials because of their physical and chemical properties. However, since they are biopersistent fiber-like materials which share similarities with asbestos, concerns have arisen about their health effects. With their various industrial usages, occupational exposure to MWCNTs may occur mainly by inhalation as these nanomaterials can get aerosolised. The number of toxicological studies on CNTs has steadily increased for the last decades. Different works showed that MWCNT exposure by inhalation or intratracheal instillation could lead to pulmonary toxicity, such as lung inflammation, genotoxicity, fibrosis or lung cancer (Kasai et al. 2015, Kasai et al. 2016, Porter et al. 2013, Suzui et al. 2016). To date, only one MWCNT (MWNT-7) has been classified as possibly carcinogen to human (Group 2B) while the others have not been as classifiable as to their carcinogenicity to humans (Group 3) because of the lack of data on their carcinogenic potential (IARC 2017). Because of the wide variety of CNTs with various length, diameter or functionalisation, additional effort is required to assess their pulmonary toxicity. As a complementary approach to conventional toxicological assays, the omics methods are useful technologies for the mechanistic understanding of the toxicological effects observed following exposure to chemicals and particulate matters. Importantly, they can also be used as predictive tools for identifying the mode of action of other particles with similar physical and chemical characteristics. These molecular approaches may also be used for the discovery of exposure markers or early markers of adverse effects, before the appearance of clinical signs of a disease (Rahman et al. 2017). Several studies assessed gene expression alteration following in vivo exposure to CNTs (Poulsen et al. 2015, Snyder-Talkington et al. 2013, Ellinger-Ziegelbauer and Pauluhn 2009). These omics approaches were used to identify genes and pathways modulated in response to exposure. However, there are still too few studies to assess the link between MWCNT physico-chemical properties, global gene or protein expression profiles, and long-term effects. In a previous study, we showed that inhalation of two pristine MWCNTs, the long and thick NM-401, and the short and thin NM-403, induced alveolar neutrophilic granulocyte influx, a hallmark of inflammation, which was proportional to the lung CNT BET surface deposited dose (Gate et al. 2019). However, due to their different physical and chemical properties, one could assume that these two CNTs may have diverse toxicological profiles, but the conventional toxicology approaches used in this early work were probably not sensitive enough to identify such differences. In order to gain additional insight about their toxicological properties, in the current study, we compare the alteration induced by the two MWCNTs on the transcriptome in the lung tissue and the proteome in the broncho-alveolar lavage fluid (BALF) after rat exposure by inhalation. The omics analyses were performed from 3 days up to 180 days.

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Overcoming qRT-PCR interference by select carbon nanotubes in assessments of gene expression.

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Overcoming qRT-PCR interference by select carbon nanotubes in assessments of gene expression.

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