Background: Cellular homeostasis is regulated by the intricate interplay between a plethora
of signaling pathways and “energetic sensors” in organs. In order to maintain energy balance, induction
or repression of metabolic pathways must be regulated and act in concert with the energetic demands
of the cell at a given point in time. A new class of small noncoding RNAs, the microRNAs
(miRNAs), has added yet further complexity to the control of metabolic homeostasis.
Objective: Understanding the damages induced by toxins in the liver and the intestine as well as the
interplay between the miRNome and transcriptome first requires baseline characterization in these tissues
in healthy animals under cellular homeostasis.
Methods: The liver (main site for detoxification) and the gut (primary exposure routes for contaminant
exposure) were dissected out (wildtype fish), total and small RNA extracted, mRNA and miRNA libraries
constructed and subjected to high throughput sequencing. Differential Expression (DE) analysis
was performed comparing liver with gut and an “miRNA matrix” that integrates the miRNA-seq
and mRNA-seq data was constructed.
Results: Both the miRNome and transcriptome of the liver and gut tissues were characterized and putative
novel miRNAs were identified. Exploration of the “miRNA matrix” regulatory network revealed
that miRNAs uniquely expressed in the liver or gut tissue regulated fundamental cellular processes
important for both organs, and that commonly expressed miRNAs in both tissues regulated biological
processes that were specific to either the liver or the gut.
Conclusion: The result of our analyses revealed new insights into microRNA function in these tissues.