Caloric restriction and intermittent fasting are known to improve glucose homeostasis and insulin resistance in several species including humans. The aim of this study was to unravel potential mechanisms by which these interventions improve insulin sensitivity and protect from type 2 diabetes. Diabetes-susceptible New Zealand Obese mice were either 10% calorie restricted (CR) or fasted every other day (IF), and compared to ad libitum (AL) fed control mice. AL mice showed a diabetes prevalence of 43%, whereas mice under CR and IF were completely protected against hyperglycemia. Proteomic analysis of hepatic lipid droplets revealed significantly higher levels of PSMD9 (co-activator Bridge-1), MIF (macrophage migration inhibitor factor), TCEB2 (transcription elongation factor B (SIII), polypeptide 2), ACY1 (aminoacylase 1) and FABP5 (fatty acid binding protein 5), and a marked reduction of GSTA3 (glutathione S-transferase alpha 3) in samples of CR and IF mice. In addition, accumulation of diacylglycerols (DAGs) was significantly reduced in livers of IF mice (P=0.045) while CR mice showed a similar tendency (P=0.062). In particular, 9 DAG species were significantly reduced in response to IF, of which DAG-40:4 and DAG-40:7 also showed significant effects after CR. This was associated with a decreased PKCε activation and might explain the improved insulin sensitivity. In conclusion, our data indicate that protection against diabetes upon caloric restriction and intermittent fasting associates with a modulation of lipid droplet protein composition and reduction of intracellular DAG species.

Unicellular organisms have the prevalent challenge to survive under oxidative stress of reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂). ROS are present as by-products of photosynthesis and aerobic respiration. These reactive species are even employed by multicellular organisms as potent weapons against microbes. Although bacterial defences against lethal and sub-lethal oxidative stress have been studied in model bacteria, the role of fluctuating H₂O₂ concentrations remains unexplored. It is known that sub-lethal exposure of Escherichia coli to H₂O₂ results in enhanced survival upon subsequent exposure. Here we investigate the priming response to H₂O₂ at physiological concentrations. The basis and the duration of the response (memory) were also determined by time-lapse quantitative proteomics. We found that a low level of H₂O₂ induced several scavenging enzymes showing a long half-life, subsequently protecting cells from future exposure. We then asked if the phenotypic resistance against H₂O₂ alters the evolution of resistance against oxygen stress. Experimental evolution of H₂O₂ resistance revealed faster evolution and higher levels of resistance in primed cells. Several mutations were found to be associated with resistance in evolved populations affecting different loci but, counterintuitively, none of them was directly associated with scavenging systems. Our results have important implications for host colonisation and infections where microbes often encounter reactive oxygen species in gradients. Throughout evolution, bacteria were exposed to reactive oxygen species and evolved the ability to scavenge toxic oxygen radicals. Furthermore, multicellular organisms evolved the ability to produce such oxygen species directed against pathogens. Recent studies also suggest that ROS such as H₂O₂ play an important role during host gut colonisation by its microbiota. Traditionally, experiments with different antimicrobials have been carried out using fixed concentrations while in nature, including in intra-host environments, microbes are more likely to experience this type of stress in steps or gradients. Here we show that bacteria treated with sub-lethal concentrations of H₂O₂ (priming) survive far better than non-treated cells when they subsequently encounter a higher concentration. We also found that the 'priming' response has a protective role from lethal mutagenesis. This protection is provided by long-lived proteins that, upon priming, remain at a high level for several generations as determined by time-lapse LC-mass spectrometry. Bacteria that were primed evolved H₂O₂ resistance faster and to a higher level. Moreover, mutations that increase resistance to H₂O₂, as determined by whole-genome sequencing (WGS), do not occur in known scavenger encoding genes but in loci coding for other functions, at least in E. coli.

About half of mammalian miRNA genes lie within introns of protein-coding genes, yet little is known about functional interactions between miRNAs and their host genes. The intronic miRNA miR-128 regulates neuronal excitability and dendritic morphology of principal neurons during mouse cerebral cortex development. Its conserved host genes, R3hdm1 and Arpp21, are predicted RNA-binding proteins. Here we use iCLIP to characterize ARPP21 recognition of uridine-rich sequences with high specificity for 3′UTRs. ARPP21 antagonizes miR-128 activity by co-regulating a subset of miR-128 target mRNAs enriched for neurodevelopmental functions. Protein–protein interaction data and functional assays suggest that ARPP21 acts as a positive post-transcriptional regulator by interacting with the translation initiation complex eIF4F. This molecular antagonism is reflected in inverse activities during dendritogenesis: miR-128 overexpression or knockdown of ARPP21 reduces dendritic complexity; ectopic ARPP21 leads to an increase. Thus, we describe a unique example of convergent function by two products of a single gene.

The pathogenesis of Alzheimer's disease (AD) is characterized by the aggregation of amyloid-β (Aβ) peptides leading to deposition of senile plaques and a progressive decline of cognitive functions, which currently remains the main criterion for its d

Background and purpose: Nanogels (NGs) are promising drug delivery tools but are typically limited to hydrophilic drugs. Many potential new drugs are hydrophobic. Our study systematically investigates amphiphilic NGs with varying hydrophobicity, but similar colloidal features to ensure comparability. The amphiphilic NGs used in this experiment consist of a hydrophilic polymer network with randomly distributed hydrophobic groups. For the synthesis we used a new synthetic platform approach. Their amphiphilic character allows the encapsulation of hydrophobic drugs. Importantly, the hydrophilic/hydrophobic balance determines drug loading and biological interactions. In particular, protein adsorption to NG surfaces is dependent on hydrophobicity and critically determines circulation time. Our study investigates how network hydrophobicity influences protein binding, biocompatibility and cellular uptake. Methods: Biocompatibility of the NGs was examined by WST-1 assay in monocytic-like THP-1 cells. Serum protein corona formation was investigated using dynamic light scattering and two-dimensional gel electrophoresis. Proteins were identified by liquid chromatography-tandem mass spectrometry. In addition, cellular uptake was analyzed via flow cytometry. Results: All NGs were highly biocompatible. The protein binding patterns for the two most hydrophobic NGs were very similar to each other but clearly different from the hydrophilic ones. Overall, protein binding was increased with increasing hydrophobicity, resulting in increased cellular uptake. Conclusion: Our study supports the establishment of structure–property relationships and contributes to the accurate balance between maximum loading capacity with low protein binding, optimal biological half-life and good biocompatibility. This is an important step to derive design principles of amphiphilic NGs to be applied as drug delivery vehicles.