Structure-activity and in vivo evaluation of a novel lipoprotein lipase (LPL) activator

Elevated triglycerides (TG) contribute towards increased risk for cardiovascular disease. Lipoprotein lipase (LPL) is an enzyme that is responsible for the metabolism of core triglycerides of very-low density lipoproteins (VLDL) and chylomicrons in the vasculature. In this study, we explored the structure-activity relationships of our lead compound (C10d) that we have previously identified as an LPL agonist. We found that the cyclopropyl moiety of C10d is not absolutely necessary for LPL activity. Several substitutions were found to result in loss of LPL activity. The compound C10d was also tested in vivo for its lipid lowering activity. Mice were fed a high-fat diet (HFD) for four months, and treated for one week at 10 mg/kg. At this dose, C10d exhibited in vivo biological activity as indicated by lower TG and cholesterol levels as well as reduced body fat content as determined by ECHO-MRI. Furthermore, C10d also reduced the HFD induced fat accumulation in the liver. Our study has provided insights into the structural and functional characteristics of this novel LPL activator

Silver Binding to Bacterial Glutaredoxins Observed by NMR

Glutaredoxins (GRXs) are a class of enzymes used in the reduction of protein thiols and the removal of reactive oxygen species. The CPYC active site of GRX is a plausible metal binding site, but was previously theorized not to bind metals due to its cis-proline configuration. We have shown that not only do several transition metals bind to the CPYC active site of the Brucella melitensis GRX but also report a model of a dimeric GRX in the presence of silver. This metal complex has also been characterized using enzymology, mass spectrometry, size exclusion chromatography, and molecular modeling. Metalation of GRX unwinds the end of the helix displaying the CPYC active site to accommodate dimerization in a way that is similar to iron sulfur cluster binding in related homologs and may imply that metal binding is a more common occurrence in this class of oxidoreductases than previously appreciated

Silver Binding to Bacterial Glutaredoxins Observed by NMR

Glutaredoxins (GRXs) are a class of enzymes used in the reduction of protein thiols and the removal of reactive oxygen species. The CPYC active site of GRX is a plausible metal binding site, but was previously theorized not to bind metals due to its cis-proline configuration. We have shown that not only do several transition metals bind to the CPYC active site of the Brucella melitensis GRX but also report a model of a dimeric GRX in the presence of silver. This metal complex has also been characterized using enzymology, mass spectrometry, size exclusion chromatography, and molecular modeling. Metalation of GRX unwinds the end of the helix displaying the CPYC active site to accommodate dimerization in a way that is similar to iron sulfur cluster binding in related homologs and may imply that metal binding is a more common occurrence in this class of oxidoreductases than previously appreciated

Cuprizone Intoxication Induces Cell Intrinsic Alterations in Oligodendrocyte Metabolism Independent of Copper Chelation

Cuprizone intoxication is a common animal model used to test myelin regenerative therapies for the treatment of diseases such as multiple sclerosis. Mice fed this copper chelator develop reversible, region-specific oligodendrocyte loss and demyelination. While the cellular changes influencing the demyelinating process have been explored in this model, there is no consensus about the biochemical mechanisms of toxicity in oligodendrocytes and about whether this damage arises from the chelation of copper <i>in vivo</i>. Here we have identified an oligodendroglial cell line that displays sensitivity to cuprizone toxicity and performed global metabolomic profiling to determine biochemical pathways altered by this treatment. We link these changes with alterations in brain metabolism in mice fed cuprizone for 2 and 6 weeks. We find that cuprizone induces widespread changes in one-carbon and amino acid metabolism as well as alterations in small molecules that are important for energy generation. We used mass spectrometry to examine chemical interactions that are important for copper chelation and toxicity. Our results indicate that cuprizone induces global perturbations in cellular metabolism that may be independent of its copper chelating ability and potentially related to its interactions with pyridoxal 5′-phosphate, a coenzyme essential for amino acid metabolism