title: The beagle dog MicroRNA tissue atlas: identifying translatable biomarkers of organ toxicity.
abstract: MicroRNAs (miRNA) are varied in length, under 25 nucleotides, single-stranded noncoding RNA that regulate post-transcriptional gene expression via translational repression or mRNA degradation. Elevated levels of miRNAs can be detected in systemic circulation after tissue injury, suggesting that miRNAs are released following cellular damage. Because of their remarkable stability, ease of detection in biofluids, and tissue specific expression patterns, miRNAs have the potential to be specific biomarkers of organ injury. The identification of miRNA biomarkers requires a systematic approach: 1) determine the miRNA tissue expression profiles within a mammalian species via next generation sequencing; 2) identify enriched and/or specific miRNA expression within organs of toxicologic interest, and 3) in vivo validation with tissue-specific toxicants. While miRNA tissue expression has been reported in rodents and humans, little data exists on miRNA tissue expression in the dog, a relevant toxicology species. The generation and evaluation of the first dog miRNA tissue atlas is described here.
  
  
  
  Analysis of 16 tissues from five male beagle dogs identified 106 tissue enriched miRNAs, 60 of which were highly enriched in a single organ, and thus may serve as biomarkers of organ injury. A proof of concept study in dogs dosed with hepatotoxicants evaluated a qPCR panel of 15 tissue enriched miRNAs specific to liver, heart, skeletal muscle, pancreas, testes, and brain. Dogs with elevated serum levels of miR-122 and miR-885 had a correlative increase of alanine aminotransferase, and microscopic analysis confirmed liver damage. Other non-liver enriched miRNAs included in the screening panel were unaffected. Eli Lilly authors created a complimentary Sprague Dawely rat miRNA tissue atlas and demonstrated increased pancreas enriched miRNA levels in circulation, following caerulein administration in rat and dog.
  
  
  
  The dog miRNA tissue atlas provides a resource for biomarker discovery and can be further mined with refinement of dog genome annotation. The 60 highly enriched tissue miRNAs identified within the dog miRNA tissue atlas could serve as diagnostic biomarkers and will require further validation by in vivo correlation to histopathology. Once validated, these tissue enriched miRNAs could be combined into a powerful qPCR screening panel to identify organ toxicity during early drug development.
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA. Erik.Koenig@Takeda.com.
authors.forename: Erik M
authors.initials: EM
authors.lastname: Koenig
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Craig
authors.initials: C
authors.lastname: Fisher
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Hugues
authors.initials: H
authors.lastname: Bernard
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Francis S
authors.initials: FS
authors.lastname: Wolenski
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Gerrein
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Carsillo
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Matt
authors.initials: M
authors.lastname: Gallacher
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Aimy
authors.initials: A
authors.lastname: Tse
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Peters
authors.affiliation: Eli Lilly and Company, 893 S. Delaware, Indianapolis, IN, 46285, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Smith
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Alexa
authors.initials: A
authors.lastname: Meehan
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Tirrell
authors.affiliation: Takeda Pharmaceuticals International Co., 40 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Kirby
mesh_terms: D000818:Animals; D015415:Biomarkers; D016000:Cluster Analysis; D019295:Computational Biology / Q000379:methods; D004285:Dogs; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D059014:High-Throughput Nucleotide Sequencing; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D058977:Molecular Sequence Annotation; D009928:Organ Specificity / Q000235:genetics; D059467:Transcriptome
chemical_list: D015415:Biomarkers; D035683:MicroRNAs