ObjectiveInfants born to mothers with obesity have greater adiposity, ectopic fat storage, and are at increased risk for childhood obesity and metabolic disease compared with infants of normal weight mothers, though the cellular mechanisms mediating these effects are unclear.MethodsWe tested the hypothesis that human, umbilical cord-derived mesenchymal stem cells (MSCs) from infants born to obese (Ob-MSC) versus normal weight (NW-MSC) mothers demonstrate altered fatty acid metabolism consistent with adult obesity. In infant MSCs undergoing myogenesis in vitro, we measured cellular lipid metabolism and AMPK activity, AMPK activation in response to cellular nutrient stress, and MSC DNA methylation and mRNA content of genes related to oxidative metabolism.ResultsWe found that Ob-MSCs exhibit greater lipid accumulation, lower fatty acid oxidation (FAO), and dysregulation of AMPK activity when undergoing myogenesis in vitro. Further experiments revealed a clear phenotype distinction within the Ob-MSC group where more severe MSC metabolic perturbation corresponded to greater neonatal adiposity and umbilical cord blood insulin levels. Targeted analysis of DNA methylation array revealed Ob-MSC hypermethylation in genes regulating FAO (PRKAG2, ACC2, CPT1A, SDHC) and corresponding lower mRNA content of these genes. Moreover, MSC methylation was positively correlated with infant adiposity.ConclusionsThese data suggest that greater infant adiposity is associated with suppressed AMPK activity and reduced lipid oxidation in MSCs from infants born to mothers with obesity and may be an important, early marker of underlying obesity risk.

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Cholera toxin (CT) moves from the cell surface to the endoplasmic reticulum (ER) where the catalytic CTA1 subunit separates from the holotoxin and unfolds due to its intrinsic instability. Unfolded CTA1 then moves through an ER translocon pore to reach its cytosolic target. Due to the instability of CTA1, it must be actively refolded in the cytosol to achieve the proper conformation for modification of its G protein target. The cytosolic heat shock protein Hsp90 is involved with the ER-to-cytosol translocation of CTA1, yet the mechanistic role of Hsp90 in CTA1 translocation remains unknown. Potential post-translocation roles for Hsp90 in modulating the activity of cytosolic CTA1 are also unknown. Here, we show by isotope-edited Fourier transform infrared spectroscopy that Hsp90 induces a gain-of-function in disordered CTA1 at physiological temperature. Only the ATP-bound form of Hsp90 interacts with disordered CTA1, and its refolding of CTA1 is dependent upon ATP hydrolysis. Surface plasmon resonance experiments found that Hsp90