Extent, causes, and consequences of small RNA expression variation in human adipose tissue

PLoS Genet. 2012;8(5):e1002704. doi: 10.1371/journal.pgen.1002704. Epub 2012 May 10.

Abstract

Small RNAs are functional molecules that modulate mRNA transcripts and have been implicated in the aetiology of several common diseases. However, little is known about the extent of their variability within the human population. Here, we characterise the extent, causes, and effects of naturally occurring variation in expression and sequence of small RNAs from adipose tissue in relation to genotype, gene expression, and metabolic traits in the MuTHER reference cohort. We profiled the expression of 15 to 30 base pair RNA molecules in subcutaneous adipose tissue from 131 individuals using high-throughput sequencing, and quantified levels of 591 microRNAs and small nucleolar RNAs. We identified three genetic variants and three RNA editing events. Highly expressed small RNAs are more conserved within mammals than average, as are those with highly variable expression. We identified 14 genetic loci significantly associated with nearby small RNA expression levels, seven of which also regulate an mRNA transcript level in the same region. In addition, these loci are enriched for variants significant in genome-wide association studies for body mass index. Contrary to expectation, we found no evidence for negative correlation between expression level of a microRNA and its target mRNAs. Trunk fat mass, body mass index, and fasting insulin were associated with more than twenty small RNA expression levels each, while fasting glucose had no significant associations. This study highlights the similar genetic complexity and shared genetic control of small RNA and mRNA transcripts, and gives a quantitative picture of small RNA expression variation in the human population.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Glucose
  • Body Fat Distribution
  • Body Mass Index
  • Fasting
  • Female
  • Gene Expression Regulation
  • Genetic Variation*
  • Genome-Wide Association Study
  • Genotype
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Insulin / blood
  • MicroRNAs* / genetics
  • MicroRNAs* / metabolism
  • Middle Aged
  • Polymorphism, Single Nucleotide
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • RNA, Small Nucleolar* / genetics
  • RNA, Small Nucleolar* / metabolism
  • RNA, Small Untranslated / genetics*
  • RNA, Small Untranslated / metabolism
  • Subcutaneous Fat* / metabolism

Substances

  • Blood Glucose
  • Insulin
  • MicroRNAs
  • RNA, Messenger
  • RNA, Small Nucleolar
  • RNA, Small Untranslated