Epigenetic Silencing of Carotid Body TRPM7 Attenuates Hypertension in Obese Mice

Obesity is the most common cause of hypertension. We have previously shown that high levels of circulating leptin in diet-induced obese (DIO) mice induced hypertension by increasing expression of Transient Receptor Potential Melastatin-subfamily member 7 (TRPM7) in the carotid bodies (CB). In addition, we demonstrated in rat PC12 cells that leptin increases <i>Trpm7</i> gene expression by inducing CpG site-specific demethylation within the 5' regulatory region containing a signal transducer and activator of transcription 3 (STAT3) binding site. This leptin-induced <i>Trpm7</i> upregulation was prevented by inhibition of JAK-STAT3 signaling. Based on these findings, we hypothesized that reversing region-specific methylation at the <i>Trpm7</i> promoter in the CB could attenuate obesity-associated hypertension. Compared with lean controls, DIO mice exhibited increased <i>Trpm7</i> expression and the STAT3- binding site-specific promoter demethylation in the CB. Administration of methylated DNA oligonucleotides targeting the STAT3 binding site attenuated CpG site-specific DNA demethylation and reduced <i>Trpm7</i> transcription in the CB of DIO mice. This intervention resulted in decreased carotid sinus nerve activity and reduced arterial blood pressure, especially during the light phase. Our results suggest that targeted modulation of CpG site-specific DNA methylation at the <i>Trpm7</i> promoter using DNA oligonucleotide may represent a novel therapeutic strategy for obesity-induced hypertension.