title: Formaldehyde and epigenetic alterations: microRNA changes in the nasal epithelium of nonhuman primates.
abstract: BACKGROUND
  Formaldehyde is an air pollutant present in both indoor and outdoor atmospheres. Because of its ubiquitous nature, it is imperative to understand the mechanisms underlying formaldehyde-induced toxicity and carcinogenicity. MicroRNAs (miRNAs) can influence disease caused by environmental exposures, yet miRNAs are understudied in relation to formaldehyde. Our previous investigation demonstrated that formaldehyde exposure in human lung cells caused disruptions in miRNA expression profiles in vitro.
  
  
  OBJECTIVE
  Using an in vivo model, we set out to test the hypothesis that formaldehyde inhalation exposure significantly alters miRNA expression profiles within the nasal epithelium of nonhuman primates.
  
  
  METHODS
  Cynomolgus macaques were exposed by inhalation to approximately 0, 2, or 6 ppm formaldehyde for 6 hr/day for 2 consecutive days. Small RNAs were extracted from nasal samples and assessed for genome-wide miRNA expression levels. Transcriptional targets of formaldehyde-altered miRNAs were computationally predicted, analyzed at the systems level, and assessed using real-time reverse transcriptase polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  Expression analysis revealed that 3 and 13 miRNAs were dysregulated in response to 2 and 6 ppm formaldehyde, respectively. Transcriptional targets of the miRNA with the greatest increase (miR-125b) and decrease (miR-142-3p) in expression were predicted and analyzed at the systems level. Enrichment was identified for miR-125b targeting genes involved in apoptosis signaling. The apoptosis-related targets were functionally tested using RT-PCR, where all targets showed decreased expression in formaldehyde-exposed samples.
  
  
  CONCLUSIONS
  Formaldehyde exposure significantly disrupts miRNA expression profiles within the nasal epithelium, and these alterations likely influence apoptosis signaling.
authors: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors: Julia E
authors: JE
authors: Rager
authors: Benjamin C
authors: BC
authors: Moeller
authors: Melanie
authors: M
authors: Doyle-Eisele
authors: Dean
authors: D
authors: Kracko
authors: James A
authors: JA
authors: Swenberg
authors: Rebecca C
authors: RC
authors: Fry
mesh_terms: D000818:Animals; D017209:Apoptosis; D044127:Epigenesis, Genetic / Q000187:drug effects*; D005557:Formaldehyde / Q000633:toxicity*; D008252:Macaca fascicularis; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D009297:Nasal Mucosa / Q000187:drug effects* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011323:Primates; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D035683:MicroRNAs; D005557:Formaldehyde