Visualization of subcellular organelles in vivo is critical for basic biomedical research and clinical applications. Two new flavonoids with an amide substituent were synthesized and characterized. The flavonoids were nearly non-fluorescent in aqueous environment, but exhibited two emission peaks (one λem at 495–536 nm and the other at 570–587 nm) in organic solvents, which were assigned to the excited normal (N*) and tautomer (T*) emission. When the dyes were examined on oligodendrocyte cells, they were found to selectively accumulate in the endoplasmic reticulum (ER), a eukaryotic organelle involved in lipid and protein synthesis, giving fluorescence turn-on. The ER-selective flavonoids could be a valuable tool due to its low molecular mass (<500), large Stokes' shift, low toxicity, and biocompatibility.
Oxidative stress contributes to pathology associated with inflammatory brain disorders and therapies that upregulate antioxidant pathways may be neuroprotective in diseases such as multiple sclerosis. Dimethyl fumarate, a small molecule therapeutic for multiple sclerosis, activates cellular antioxidant signaling pathways and may promote myelin preservation. However, it is still unclear what mechanisms may underlie this neuroprotection and whether dimethyl fumarate affects oligodendrocyte responses to oxidative stress. Here, we examine metabolic alterations in oligodendrocytes treated with dimethyl fumarate by using a global metabolomic platform that employs both hydrophilic interaction liquid chromatography-mass spectrometry and shotgun lipidomics. Prolonged treatment of oligodendrocytes with dimethyl fumarate induces changes in citric acid cycle intermediates, glutathione, and lipids, indicating that this compound can directly impact oligodendrocyte metabolism. These metabolic alterations are also associated with protection from oxidant challenge. This study provides insight into the mechanisms by which dimethyl fumarate could preserve myelin integrity in patients with multiple sclerosis.
Mechanochemical approaches to chemical synthesis offer the promise of improved yields, new reaction pathways and greener syntheses. Scaling these syntheses is a crucial step toward realizing a commercially viable process. Although much work has been performed on laboratory-scale investigations little has been done to move these approaches toward industrially relevant scales. Moving reactions from shaker-type mills and planetary-type mills to scalable solutions can present a challenge. We have investigated scalability through discrete element models, thermal monitoring and reactor design. We have found that impact forces and macroscopic mixing are important factors in implementing a truly scalable process. These observations have allowed us to scale reactions from a few grams to several hundred grams and we have successfully implemented scalable solutions for the mechanocatalytic conversion of cellulose to value-added compounds and the synthesis of edge functionalized graphene.