NNAT and Insulin resistance: On the other hand, mRNA expression of genes increased in I-Res male and female iMyos, including Rho GTPase activating protein 25 (ARHGAP25), 17-β-hydroxysteroid dehydrogenase (HSD17B14), and neuronatin (NNAT), remained unaffected following treatment with 5-Az (Figure 5E), suggesting that DNA methylation is not a major contributor to the gene expression changes associated with insulin resistance.