Main principles and outcomes of DNA methylation analysis

Attenuation of mitochondrial dysfunction in a ventricular fibrillation swine model of cardiac arrest treated with carbon monoxide

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) affects over 360,000 adults in the United States each year with a 50-80% mortality. Despite aggressive supportive care and use of targeted temperature management, half of adults do not live to hospital discharge and nearly one-third of survivors have significant neurologic injury. Development of neuroprotective therapeutics is critical to improving outcomes. One promising readily available agent that has shown benefit is carbon monoxide (CO).

METHODS

We utilize a swine model of ventricular fibrillation (VF) arrest to assess the therapeutic effect of CO on cellular measures. All animals underwent VF arrest followed by cardiopulmonary resuscitation until achievement of return of spontaneous circulation (ROSC) or the 20 min mark. One hour following ROSC, animals were randomized to the Cardiac Arrest group (VF alone) versus the CO group (VF treated with CO). Animals in the CO group were administered low dose CO of 200 ppm for two hours. At three hours post-ROSC period, all animals were euthanized for tissue and blood collection for mitochondrial respiration (cortical and hippocampal tissue) and the downstream biomolecular analysis.

RESULTS

The primary findings were an overall improvement in mitochondrial respiration and ATP concentrations in the brain from animals in the Carbon Monoxide group. In addition, we also report the use of cell-free DNA as a biomarker to localize the site of tissue injury and our non-invasive optical measuring device to assess cerebral metabolism.

CONCLUSIONS

CO may be a potential therapeutic to attenuate cellular injury in post-arrest.

The Methylation Analysis of the Glucose-Dependent Insulinotropic Polypeptide Receptor (GIPR) Locus in GH-Secreting Pituitary Adenomas

The glucose-dependent insulinotropic polypeptide receptor (GIPR) is aberrantly expressed in about one-third of GH-secreting pituitary adenomas (GH-PAs) and has been associated with a paradoxical increase of GH after a glucose load. The reason for such an overexpression has not yet been clarified. In this work, we aimed to evaluate whether locus-specific changes in DNA methylation patterns could contribute to this phenomenon. By cloning bisulfite-sequencing PCR, we compared the methylation pattern of the GIPR locus in GIPR-positive (GIPR⁺) and GIPR-negative (GIPR^-) GH-PAs. Then, to assess the correlation between Gipr expression and locus methylation, we induced global DNA methylation changes by treating the lactosomatotroph GH3 cells with 5-aza-2'-deoxycytidine. Differences in methylation levels were observed between GIPR⁺ and GIPR^- GH-PAs, both within the promoter (31.9% vs. 68.2%, p < 0.05) and at two gene body regions (GB_1 20.7% vs. 9.1%; GB_2 51.2% vs. 65.8%, p < 0.05). GH3 cells treated with 5-aza-2'-deoxycytidine showed a ~75% reduction in Gipr steady-state level, possibly associated with the observed decrease in CpGs methylation. These results indicate that epigenetic regulation affects GIPR expression in GH-PAs, even though this possibly represents only a part of a much more complex regulatory mechanism.

Pregnancy lipidomic profiles and DNA methylation in newborns from the CHAMACOS cohort

Lipids play a role in many biological functions and the newly emerging field of lipidomics aims to characterize the varying classes of lipid molecules present in biological specimens. Animal models have shown associations between maternal dietary supplementation with fatty acids during pregnancy and epigenetic changes in their offspring, demonstrating a mechanism through which prenatal environment can affect outcomes in children; however, data on maternal lipid metabolite levels during pregnancy and newborn DNA methylation in humans are sparse. In this study, we assessed the relationship of maternal lipid metabolites measured in the blood from pregnant women with newborn DNA methylation profiles in the Center for the Health Assessment of Mothers and Children of Salinas cohort. Targeted metabolomics was performed by selected reaction monitoring liquid chromatography and triple quadrupole mass spectrometry to measure 92 metabolites in plasma samples of pregnant women at ∼26 weeks gestation. DNA methylation was assessed using the Infinium HumanMethylation 450K BeadChip adjusting for cord blood cell composition. We uncovered numerous false discovery rate significant associations between maternal metabolite levels, particularly phospholipid and lysolipid metabolites, and newborn methylation. The majority of the observed relationships were negative, suggesting that higher lipid metabolites during pregnancy are associated with lower methylation levels at genes related to fetal development. These results further elucidate the complex relationship between early life exposures, maternal lipid metabolites, and infant epigenetic status.