Mitochondria mediated changes in obese pregnancies

Maternal obesity alters mitochondria function in offspring which is associated with abnormal mitochondria function in key metabolic tissues. Treating the pregnant dam with antioxidants prevents the development of obesity in the offspring. These studies strongly suggest that maternal obesity alters mitochondria function in the offspring which is directly linked to the development of obesity and the metabolic syndrome later in life. The molecular mechanisms by which this process occurs is the focus of this proposal. Extracellular vesicles (EVs) contain mitochondria components such as mtDNA and protein, which can be incorporated into the recipient cell mitochondria network resulting in changes in mitochondria function. Adipose tissue produces large numbers of EVs which induce inflammation, modulate glucose and lipid metabolism and recently have been shown to alter placenta function. We hypothesize that obesity during pregnancy increases the secretion of EVs from adipose tissue that contain abnormal mitochondrial cargo, and that these EVs traffic to the embryo, leading to abnormal mitochondria function which in turn reprograms the offspring to develop obesity later in life. In SA1 we will test the hypothesis that transfer of damaged EV mitochondria cargo to the embryo preferentially alters the metabolic homeostasis in the male embryo and offspring of the obese dam. Using our established murine model of obesity in pregnancy, we will isolate and characterize circulating adipocyte EVs from plasma and adipose tissue of obese and lean pregnant dams. In vitro experiments will assess the capability of circulating or in vitro obtained adipocyte EVs from early pregnant obese dams of transferring mitochondria cargo to preimplantation embryos thereby altering embryo metabolic function. Using an in vivo approach, we will determine if circulating adipocyte EVs from obese pregnant dams transfer abnormal mitochondria cargo that is incorporated into mitochondria of embryos from lean pregnant dams. We will generate transgenic mice expressing a mitochondria tag only in extracellular vesicles (Cd9-GFP cre/mKate2). Finally, EVs will be isolated from obese transgenic pregnant mice and injected into lean pregnant mice daily from e1-e4.5. E4.5 embryos will be harvested and localization of donor EV mitochondria to the mitochondria network of the recipient embryo will be assessed by immunofluorescent microscopy. Mitochondria function of e4.5 recipient embryos will also be measured. Body composition, glucose tolerance, and localization of maternally derived mitochondria will be assessed in offspring in adulthood. To determine the specific effect of EVs on embryo metabolic function, embryo transfer experiments will also be performed. In SA2 we will test the hypothesis that in the presence of maternal obesity, maternal adipocyte EVs carrying damaged mitochondria cargo alter the epigenome of the embryo in a sex-specific manner. Single-cell RNAseq and ATACseq will be performed in the same cell and genome-wide DNA methylation will be assessed in parallel and results compared between male and females. Genomic interactions will be mapped by chromatin capture. Novel analytic pipelines will be used to map cell-cell interactions using the integrated omics data. Project Number: 1R01HD113889-01A1 | Fiscal Year: 2025 | NIH Institute/Center: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | Principal Investigator: Rebecca Simmons | Institution: UNIVERSITY OF PENNSYLVANIA, PHILADELPHIA, PA | Award Amount: $601,499 | Activity Code: R01 | Study Section: Pregnancy and Neonatology Study Section[PN] View on NIH RePORTER: https://reporter.nih.gov/project-details/1R01HD11388901A1