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Molecular Mechanisms Linking Amino Acid (Leucine) Deprivation To Igfbp-1 Hyperphosphorylation In Fetal Growth Restriction, Niyati M. Malkani
Molecular Mechanisms Linking Amino Acid (Leucine) Deprivation To Igfbp-1 Hyperphosphorylation In Fetal Growth Restriction, Niyati M. Malkani
Electronic Thesis and Dissertation Repository
In this study, we explore the molecular mechanisms linking amino acid (leucine) deprivation to IGFBP-1 hyperphosphorylation in vitro. During pregnancy, a maladaptive fetal response to in utero amino acid deprivation leads to Fetal Growth Restriction (FGR). FGR infants display elevated phosphorylated IGFBP-1, which is associated with decreased IGF-I bioavailability. Leucine deprivation inhibits mechanistic target of rapamycin (mTOR) signaling and stimulates the amino acid response (AAR). Using HepG2 cells, a model for fetal hepatocytes, we demonstrate that in leucine deprivation, the AAR modulates total and phosphorylated IGFBP-1 while mTOR mediates total IGFBP-1 secretion only. We also reveal that protein kinases …
Nicotinamide Riboside Delivery Generates Nad+ Reserves To Protect Vascular Cells Against Oxidative Damage, Krista M. Hawrylyshyn
Nicotinamide Riboside Delivery Generates Nad+ Reserves To Protect Vascular Cells Against Oxidative Damage, Krista M. Hawrylyshyn
Electronic Thesis and Dissertation Repository
The ability of vascular cells to withstand oxidative insults is critical to vascular health. NAD+, which drives poly (ADP-ribose) polymerase (PARP) and sirtuin (SIRT) reactions, can be compromised and strategies for overcoming this limitation in the vasculature do not exist. This study determines if nicotinamide riboside (NR) delivery can augment NAD+ stores and fuel resistance to oxidative stress. I established that oxidative-stress insult on vascular cells decreased NAD+ levels, accompanied by a striking increase in nuclear PAR-chain accumulation. PARP inhibition abolished PAR-chain formation and preserved NAD+ levels, establishing PARP in NAD+ consumption in this …