Abstract
Objective MicroRNAs (miRNAs) play a critical role in metabolic regulation. Recently, we identified
novel miRNAs in the whole blood of South African women of mixed ethnic ancestry. The
aim of this study was to investigate whether five of these novel miRNAs are expressed
in serum and whether their expression is altered during metabolic dysregulation.
Methods Expression levels of the five novel miRNAs (MYN08, MYNO22, MYN059, MYNO66 and MYNO95)
were measured in the serum of women with Impaired Glucose Tolerance (IGT) and Normoglycemia
(NGT) (n=24), and in the whole blood of vervet monkeys fed a high-fat or standard
diet (n=16) using quantitative real-time PCR.
Results Only three of the selected novel miRNAs (MYNO8, MYNO22 and MYNO66) were expressed
in serum. The expression of MYN08 and MYNO22 were associated with fasting glucose
and insulin concentrations, decreased during IGT and able to predict IGT. The expression
of these miRNAs were similarly decreased in vervet monkeys fed a high-fat diet. In silico analysis identified a total of 291 putative messenger RNA targets for MYNO8 and MYNO22,
including genes involved in gluconeogenesis, carbohydrate metabolism, glucose homeostasis
and lipid transport.
Conclusion Two novel miRNAs, MYNO8 and MYNO22, are associated with metabolic dysregulation
in South African women of mixed ethnic ancestry and with high-fat diet feeding in
vervet monkeys. Furthermore, putative gene targets were enriched in biological processes
involved in key aspects of glucose regulation, which strengthens the candidacy of
these miRNAs as biomarkers for dysglycemia, and warranting further studies to assess
their clinical applicability.
Key words
novel - microRNAs - quantitative real-time PCR - impaired glucose tolerance - vervet
monkeys - high-fat diet