Ketone bodies , β-hydroxybutyrate (BHB) and acetoacetate support mammalian survival during states of energy deficit by serving as alternative source of ATP1. BHB levels are elevated during starvation, high-intensity exercise or by the low carbohydrate ketogenic diet2. Prolonged caloric restriction or fasting reduces inflammation as immune system adapts to low glucose supply and energy metabolism switches towards mitochondrial fatty acid oxidation, ketogenesis and ketolysis2-6. However, role of ketones bodies in regulation of innate immune response is unknown. We report that BHB, but neither acetoacetate nor structurally-related short chain fatty acids, butyrate and acetate, suppresses activation of the NLRP3 inflammasome in response to several structurally unrelated NLRP3 activators, without impacting NLRC4, AIM2 or non-canonical caspase-11 inflammasome activation. Mechanistically, BHB inhibits NLRP3 inflammasome by preventing K+ efflux and reducing ASC oligomerization and speck formation. The inhibitory effects of BHB on NLRP3 were not dependent on chirality or classical starvation regulated mechanisms like AMPK, reactive oxygen species (ROS), autophagy or glycolytic inhibition. BHB blocked NLRP3 inflammasome without undergoing oxidation in TCA cycle, independently of uncoupling protein-2 (UCP2), Sirt2, receptor Gpr109a and inhibition of NLRP3 did not correlate with magnitude of histone acetylation in macrophages. BHB reduced the NLRP3 inflammasome mediated IL-1β and IL-18 production in human monocytes. In vivo, BHB attenuates caspase-1 activation and IL-1β secretion in mouse models of NLRP3-mediated diseases like Muckle-Wells Syndrome (MWS), Familial Cold Autoinflammatory syndrome (FCAS) and urate crystal induce body cavity inflammation. Taken together, these findings suggest that the anti-inflammatory effects of caloric restriction or ketogenic diets may be mechanistically linked to BHB-mediated inhibition of the NLRP3 inflammasome, and point to the potential use of interventions that elevate circulating BHB against NLRP3-mediated proinflammatory diseases.

Semiconducting nanowires have the potential to function as highly sensitive and selective sensors for the label-free detection of low concentrations of pathogenic microorganisms. Successful solution-phase nanowire sensing has been demonstrated for ions, small molecules, proteins, DNA and viruses; however, 'bottom-up' nanowires (or similarly configured carbon nanotubes) used for these demonstrations require hybrid fabrication schemes, which result in severe integration issues that have hindered widespread application. Alternative 'top-down' fabrication methods of nanowire-like devices produce disappointing performance because of process-induced material and device degradation. Here we report an approach that uses complementary metal oxide semiconductor (CMOS) field effect transistor compatible technology and hence demonstrate the specific label-free detection of below 100 femtomolar concentrations of antibodies as well as real-time monitoring of the cellular immune response. This approach eliminates the need for hybrid methods and enables system-scale integration of these sensors with signal processing and information systems. Additionally, the ability to monitor antibody binding and sense the cellular immune response in real time with readily available technology should facilitate widespread diagnostic applications.

Nanowire field effect transistors (NW-FETs) can serve as ultrasensitive detectors for label-free reagents. The NW-FET sensing mechanism assumes a controlled modification in the local channel electric field created by the binding of charged molecules to the nanowire surface. Careful control of the solution Debye length is critical for unambiguous selective detection of macromolecules. Here we show the appropriate conditions under which the selective binding of macromolecules is accurately sensed with NW-FET sensors.The ability to rapidly sense minute concentrations of specific macromolecules such as DNA sequences is critical for clinical diagnostics, 1,2 genomics, 3,4 and drug discovery 3,4 and useful for applications in defense and homeland security. 5 Most current systems for macromolecular sensing rely on labels, such as radiolabeled tags or fluorophores. 6-8 Techniques that could distinguish these without the need for labels, i.e., label-free sensing, are of great interest because they would not only significantly decrease the cost and time needed for sample preparation but would also eliminate issues related to modification of target molecules. 9,10One of the most promising platforms for unlabeled sensing is the nanowire field effect transistor (NW-FET). 9-11 These devices operate similarly to conventional chemical FETs, sensing the presence of bound species by their intrinsic charge, with the advantage of enhanced sensitivity due to the nanoscale channel confinement. 11,12 By binding a receptor protein or a singlestranded DNA (ssDNA) oligomer to the NW-FET surface, the binding of the specific ligand or complementary ssDNA modifies the electric field surrounding the device, enabling direct electronic detection. [13][14][15][16] The integration issues faced by traditional, as-grown NWs have been overcome with the advent of NW-like devices patterned by "top-down" microlithography. 14-18 Although early devices suffered from low signal-to-noise ratios, a "top-down" method producing high-quality nanosensors capable of detecting specific antibodies at «10 fM concentrations have recently The charge of solution-based molecules and macromolecules is screened by dissolved solution counterions: a negative species such as streptavidin or DNA will be surrounded by positively charged ions due to electrostatic interactions. On a certain length scale, termed the Debye length (λ D ), the number of net positive charges approaches the number of negative charges on the protein or DNA. The result is a screening effect such that the electrostatic potential arising from charges on the protein or DNA decays exponentially toward zero with distance. 19 For aqueous solutions at room temperature, this length is given by NIH Public Access( 1) where l B is the Bjerrum length = 0.7 nm, ∑ i is the sum over all ion species, and ρ i and z i are the density and valence, respectively, of ion species i (ref 19). Thus, for optimal sensing, the Debye length must be carefully selected for NW-FET measurements because molecules binding to t...

The tumour microenvironment thwarts conventional immunotherapy through multiple immunologic mechanisms, such as the secretion of the transforming growth factor-β (TGF-β), which stunts local tumour immune responses. Therefore, high doses of interleukin-2 (IL-2), a conventional cytokine for metastatic melanoma, induces only limited responses. To overcome the immunoinhibitory nature of the tumour microenvironment, we developed nanoscale liposomal polymeric gels (nanolipogels; nLGs) of drug-complexed cyclodextrins and cytokine-encapsulating biodegradable polymers that can deliver small hydrophobic molecular inhibitors and water-soluble protein cytokines in a sustained fashion to the tumour microenvironment. nLGs releasing TGF-β inhibitor and IL-2 significantly delayed tumour growth, increased survival of tumour-bearing mice, and increased the activity of natural killer cells and of intratumoral-activated CD8+ T-cell infiltration. We demonstrate that the efficacy of nLGs in tumour immunotherapy results from a crucial mechanism involving activation of both innate and adaptive immune responses.