Methylation of transient receptor potential melastatin-subfamily member 7 (Trpm7) in the carotid body attenuated obesity-induced hypertension

RATIONALE: Obesity is a major cause of hypertension. We have previously shown mice with diet-induced obesity (DIO) have high levels of leptin receptor Leprb and Trpm7 gene expression in CB, and pharmacological inhibition and gene knockdown of LEPRb and TRPM7 in CB treat DIO-induced hypertension. Furthermore, we have demonstrated that leptin increases Trpm7 expression in the carotid body type I glomus cells via epigenetic mechanisms demethylating the Trpm7 promoter. Leptin binding to LEPRb activates gene transcription via phosphorylation of the transcription factor Signal Transducer and Activator of Transcription 3 (STAT3). We hypothesize that leptin demethylates the Trpm7 promoter at the pSTAT3 site and that methylation of this region using specific methylated oligonucleotides in vivo will decrease CB Trpm7 gene expression, carotid sinus nerve (CSN) activity, and blood pressure (BP) in DIO mice. METHODS: We performed in silico analysis of the Trpm7 promoter to identify putative pSTAT3 binding site(s) and generated methylated oligonucleotides (Met-oligo) complimentary to the STAT3 binding site of the Trpm7 promoter. The Met-oligo were tested in the PC-12 cell culture, which are phenotypically similar to the CB type I cells. Then, Met-oligo were applied to the CB area in DIO male mice for 2 weeks. CSN activity was measured ex vivo (n = 5 in the Met-oligo group vs n = 5 in the control oligo group). BP was measured by telemetry at baseline and after treatment (n = 6 in the Met-oligo group vs n = 8 in the control group) in DIO male mice. RESULTS: In silico analysis of the Trpm7 promoter showed that it contains putative binding sites for the transcription STAT3 and revealed CG dinucleotides (CpGs) where DNA methylation occurs. Leptin demethylated the STAT3 binding site of the Trpm7 promoter and increased Trpm7 gene expression, and these effects was abolished by Met-oligo both in vitro in PC-12 cells and in vivo in the CB of DIO mice. Leptin increased CSN activity in normoxic and hypoxic chemoreflex and these effects were abolished by Met-oligo. CB administration of the Met-oligo attenuated obesity-induced hypertension during the day, when animals were predominantly asleep, decreasing mean arterial pressure (MAP) by 5.3 ± 2.1 mmHg (p< 0.05), whereas MAP was increased by 1.4 ± 5.5 mmHg in the control group. CONCLUSION: Methylation of the Trpm7 promoter at the leptin-dependent pSTAT3 binding site in the CB abolished the leptin-induced increase in CSN activity and chemoreflex and attenuated obesity-induced hypertension. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.