RESUMO
In the modern world we are constantly bombarded by environmental and natural stimuli that can result in oxidative stress. Antioxidant molecules and enzymes help the human body scavenge reactive oxygen species and prevent oxidative damage. Most organisms possess intrinsic antioxidant activity, but also benefit from the consumption of antioxidants from their diet. Leafy green vegetables such as spinach are a well-researched rich source of dietary antioxidant molecules. However, plant cell walls are difficult to digest for many individuals and the bio-accessibility of nutrients and antioxidants from these sources can be limited by the degree of digestion and assimilation. Through a specific enzymatic process, Solarplast® contains organic spinach protoplasts without the cell wall, which may facilitate higher yield and efficacy of beneficial antioxidant molecules. In this study, analytical techniques coupled to in vitro bioassays were used to determine the potential antioxidant activity of Solarplast® and determine its antioxidant enzymatic capabilities. Solarplast® demonstrated superior antioxidant activity when compared to frozen spinach leaves in TOC, FRAP and TEAC antioxidant assays. Several antioxidant enzymes were also increased in Solarplast®, when compared to frozen spinach. As a functional readout, Solarplast® attenuated hydrogen peroxide-, ethanol- and acetaminophen-induced increases in oxidative stress and cytotoxicity in both intestinal (HT-29) and liver (HepG2) cell lines. These findings suggest that Solarplast® may represent a non-GMO, plant-based food supplement to help reduce oxidative stress in the human body.
RESUMO
Although peroxisome proliferator-activated receptor-γ (PPARγ) coactivator 1α (PGC-1α) is a well-established transcriptional coactivator for the metabolic adaptation of mammalian cells to diverse physiological stresses, the molecular mechanism by which it functions is incompletely understood. Here we used in vitro binding assays, X-ray crystallography, and immunoprecipitations of mouse myoblast cell lysates to define a previously unknown cap-binding protein 80 (CBP80)-binding motif (CBM) in the C terminus of PGC-1α. We show that the CBM, which consists of a nine-amino-acid α helix, is critical for the association of PGC-1α with CBP80 at the 5' cap of target transcripts. Results from RNA sequencing demonstrate that the PGC-1α CBM promotes RNA synthesis from promyogenic genes. Our findings reveal a new conduit between DNA-associated and RNA-associated proteins that functions in a cap-binding protein surveillance mechanism, without which efficient differentiation of myoblasts to myotubes fails to occur.