Formaldehyde (FA) is the simplest aldehyde widely used in many consumers products and various industries. FA has been recently classified as a Group I carcinogen by the International Agency for Research on Cancer. Previously, we reported that FA induced hematotoxicity and chromosomal aneuploidy in exposed workers as well as toxicities in bone marrow and hematopoietic stem cells of experimental animals. Previously,we used functional toxicogenomic profiling (loss-of-function screening) in yeast, we identified genes and cellular processes modulating FA cytotoxicity and reported FA-mediated damage to both DNA and RNA. However, specific gene pathways and mechanisms of action of FA in human cells remains unclear. We used CRISPR-Cas9 (clustered regularly interspaced short palindrome repeats) screening to test cellular processes modulating FA toxicity in human K562 cells. We carried out a loss-of-function CRISPR screen using the genome-wide Brunello library to identify modulators of FA toxicity. We used sub-toxic doses of FA (40, 100, 150 μM) and assessed the cellular genetic requirements for FA susceptibility and resistance at two time points (days 8 and 20). Using strategies for detecting differential expression and variability, we identified candidate susceptibility and resistance genes through next-generation sequencing of isolated sgRNA barcodes from pooled knock-out libraries. We will present an overview of cellular responses to FA treatment, and the individual genes and related pathways that modulate FA toxicity in K562 cells . This work provides a mechanistic understanding of the biological effects of FA in hematopoietic human cells and can potentially help inform risk assessment. Our findings suggest that CRISPR-Cas9 genome-wide screening is a cost-effective functional approach for identifying genes and pathways involved in modulating the toxicity of environmental chemicals.

Genome-wide CRISPR screening to identify modulators of formaldehyde toxicity in erythroid cells

2019 Fall National Meeting

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