Ethnic Differences in Serum Levels of microRNAs Potentially Regulating Alcohol Dehydrogenase 1B and Aldehyde Dehydrogenase 2

Ethnic difference is known in genetic polymorphisms of aldehyde dehydrogenase 2 (ALDH2) and alcohol dehydrogenase 1B (ADH1B), which cause Asian flushing by blood vessel dilation due to accumulation of acetaldehyde. We investigated ethnic differences in microRNAs (miRNAs) related to ALDH2 and ADH1B. miRNA levels in serum were totally analyzed by using miRNA oligo chip arrays and compared in Austrian and Japanese middle-aged men. There were no ALDH2- and ADH1B-related miRNAs that had previously been reported in humans and that showed significantly different serum levels between Austrian and Japanese men. With the use of miRNA prediction tools, we identified four and five miRNAs that were predicted to target ALDH2 and ADH1B, respectively, and they had expression levels high enough for comparison. Among the ADH1B-related miRNAs, miR-150-3p, -3127-5p and -4314 were significantly higher and miR-3151-5p was significantly lower in Austrian compared with Japanese men, while no significant difference was found for miR-449b-3p. miR-150-3p and miR-4314 showed relatively high fold changes (1.5 or higher). The levels of ALDH2-related miRNAs (miR-30d-5p, -6127, -6130 and -6133) were not significantly different between the countries. miR-150-3p and miR-4314 are candidates of miRNAs that may be involved in the ethnic difference in sensitivity to alcohol through modifying the expression of ADH1B.