A structural mass spectrometry strategy for the relative quantitation of ligands on mixed monolayer-protected gold nanoparticles.

It is becoming increasingly common to use gold nanoparticles (AuNPs) protected by a heterogeneous mixture of thiolate ligands, but many ligand mixtures on AuNPs cannot be properly characterized due to the inherent limitations of commonly used spectroscopic techniques. Using ion mobility-mass spectrometry (IM-MS), we have developed a strategy that allows measurement of the relative quantity of ligands on AuNP surfaces. This strategy is used for the characterization of three samples of mixed-ligand AuNPs: tiopronin:glutathione (av diameter 2.5 nm), octanethiol:decanethiol (av diameter 3.6 nm), and tiopronin:11-mercaptoundecyl(poly ethylene glycol) (av diameter 2.5 nm). For validation purposes, the results obtained for tiopronin:glutathione AuNPs were compared to parallel measurements using nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) without ion mobility separation. Relative quantitation measurements for NMR and IM-MS were in excellent agreement, with an average difference of less than 1% relative abundance. IM-MS and MS without ion mobility separation were not comparable, due to a lack of ion signals for MS. The other two mixed-ligand AuNPs provide examples of measurements that cannot be performed using NMR spectroscopy.

Targeted PI3Kδ inhibition by the small molecule idelalisib as a novel therapy in indolent non-Hodgkin lymphoma.

Indolent Non-Hodgkin Lymphomas (iNHL) are typically B-cell malignancies and are incurable with current standard approaches. Thus, there is a demand for novel agents specific for this group of disorders. In a phase II study published by Gopal et al. in the New England Journal of Medicine, idelalisib, a small molecule inhibitor of PI3Kδ that was FDA approved in July of 2014, was shown to be effective when combined with rituximab in patients who cannot tolerate chemotherapy and as last line therapy in patients with iNHL refractory to 2 prior systemic therapies. Idelalisib demonstrated tolerable diarrhea, fatigue, nausea, pyrexia, and cough. While this novel agent is a clinically significant addition to the iNHL arsenal, further research is needed to determine its most appropriate place in iNHL therapy.

Fasting and refeeding differentially regulate NLRP3 inflammasome activation in human subjects.

BACKGROUND: Activation of the NLRP3 inflammasome is associated with metabolic dysfunction, and intermittent fasting has been shown to improve clinical presentation of NLRP3 inflammasome-linked diseases. As mitochondrial perturbations, which function as a damage-associated molecular pattern, exacerbate NLRP3 inflammasome activation, we investigated whether fasting blunts inflammasome activation via sirtuin-mediated augmentation of mitochondrial integrity. METHODS: We performed a clinical study of 19 healthy volunteers. Each subject underwent a 24-hour fast and then was fed a fixed-calorie meal. Blood was drawn during the fasted and fed states and analyzed for NRLP3 inflammasome activation. We enrolled an additional group of 8 healthy volunteers to assess the effects of the sirtuin activator, nicotinamide riboside, on NLRP3 inflammasome activation. RESULTS: In the fasting/refeeding study, individuals showed less NLRP3 inflammasome activation in the fasted state compared with that in refed conditions. In a human macrophage line, depletion of the mitochondrial-enriched sirtuin deacetylase SIRT3 increased NLRP3 inflammasome activation in association with excessive mitochondrial ROS production. Furthermore, genetic and pharmacologic SIRT3 activation blunted NLRP3 activity in parallel with enhanced mitochondrial function in cultured cells and in leukocytes extracted from healthy volunteers and from refed individuals but not in those collected during fasting. CONCLUSIONS: Together, our data indicate that nutrient levels regulate the NLRP3 inflammasome, in part through SIRT3-mediated mitochondrial homeostatic control. Moreover, these results suggest that deacetylase-dependent inflammasome attenuation may be amenable to targeting in human disease. TRIAL REGISTRATION: ClinicalTrials.gov NCT02122575 and NCT00442195. FUNDING: Division of Intramural Research, NHLBI of the NIH.