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.

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 adsorption of biomolecules to the surface of nanoparticles (NPs) following administration into biological environments is widely recognized. In particular, the "protein corona" is well understood in terms of formation kinetics and impact upon the biological interactions of NPs. Its presence is an essential consideration in the design of therapeutic NPs. In the present study, the protein coronas of six polymeric nanoparticles of prospective therapeutic use were investigated. These included three colloidal NPs-soft core-multishell (CMS) NPs, plus solid cationic Eudragit RS (EGRS), and anionic ethyl cellulose (EC) nanoparticles-and three nanogels (NGs)-thermoresponsive dendritic-polyglycerol (dPG) nanogels (NGs) and two amino-functionalized dPG-NGs. Following incubation with human plasma, protein coronas were characterized and their biological interactions compared with pristine NPs. All NPs demonstrated protein adsorption and increased hydrodynamic diameters, although the solid EGRS and EC NPs bound notably more protein than the other tested particles. Shifts toward moderately negative surface charges were also observed for all corona bearing NPs, despite varied zeta potentials in their pristine states. While the uptake and cellular adhesion of the colloidal NPs in primary human keratinocytes and human umbilical vein endothelial cells were significantly decreased when bearing the protein corona, no obvious impact was seen in the NGs. By contrast, corona bearing NGs induced marked increases in cytokine release from primary human macrophages not seen with corona bearing colloidal NPs. Despite this, no apparent enhancement to in vitro toxicity was noted. Finally, drug release from EGRS and EC NPs was assessed, where a decrease was seen in the EGRS NPs alone. Together these results provide a direct comparison of the physical and biological impact the protein corona has on NPs of widely varied character and in particular highlights a distinction between the corona's effects on NGs and colloidal NPs.

The purpose of this study was to investigate the effects of hyper- and hypothyroidism on thyroid hormone concentrations and deiodinase activities in nine regions of the rat brain. Four weeks of treatment with 75 microg thyroxine (T4)/kg body wt induced a two- to threefold increase in T4 levels in all of these brain regions, whereas the 3,5,3'-triiodothyronine (T3) concentrations were reduced in five brain regions and remained unchanged in four. Even after 8 wk treatment with 300 microg T4/kg, the T3 concentrations remained normal in cortical areas, the hippocampus and amygdala, and were elevated only in areas in which inner-ring deiodinase activity was low or absent, and in the hypothalamus. At the subcellular level, nuclear concentrations of T3 were diminished in hypothyroidism but remained unaltered in hyperthyroidism in all areas except the hypothalamus, where they were enhanced. Cortical mitochondrial succinate dehydrogenase activity was reduced in both hypo- and hyperthyroidism in spite of normal T3 concentrations in hyperthyroid animals. The results show that nuclear T3 concentrations fall in hypothyroidism but do not change during severe hyperthyroidism in any brain region except the hypothalamus. Further research is thus needed to clarify the mechanisms mediating the numerous biochemical and psychological effects of hyperthyroidism.

37Mechanoelectrical transduction is a cellular signalling pathway where physical stimuli are 38 converted into electro-chemical signals by mechanically activated ion channels. We describe 39 here the presence of mechanically activated currents in melanoma cells that are dependent on 40 TMEM87a, which we have renamed Elkin1. Heterologous expression of this protein in 41 PIEZO1-deficient cells, that exhibit no baseline mechanosensitivity, is sufficient to 42 reconstitute mechanically activated currents. Melanoma cells lacking functional Elkin1 43 exhibit defective mechanoelectrical transduction, decreased motility and increased 44 dissociation from organotypic spheroids. By analysing cell adhesion properties, we 45 demonstrate that Elkin1 deletion is associated with increased cell-substrate adhesion and 46 decreased homotypic cell-cell adhesion strength. We therefore conclude that Elkin1 supports 47 a PIEZO1-independent mechanoelectrical transduction pathway and modulates cellular 48 adhesions and regulates melanoma cell migration and cell-cell interactions. 49 50 130 occurred within the stimulus range, allowing us to use a Boltzmann sigmoidal fit to determine 131 the MA current sensitivity. Half-maximal activation of MA currents was seen with 132 approximately 18 nm of substrate deflection (Effective deflection ED50; standard error = 133 20.5 nm). These data indicate a correlation between migratory properties and the MA current 134 sensitivity to deflections applied at cell-substrate contact points. The robust MA current 135 activation observed in cells cultured on LM511 also provided an excellent system to 136 investigate the molecules required for this mechanoelectrical transduction. 137 5 138 157 1999), indicating that neither likely mediates the deflection-evoked currents in WM266-4 158 cells (Figure 1-figure supplement 2). We then examined the proteomics data for proteins of 159 unknown function with 4 or more predicted transmembrane (TM) domains. We prioritised 160 the investigation of Elkin1 due to its expression in melanoma cells but not healthy 161 melanocytes, its expression in additional mechanosensitive cells (Alveolar Type II cells) and 162 its upregulation in additional human cancers (Human Protein Atlas (Uhlén et al., 2005) 163 available from www.proteinatlas.org). We generated miRNA constructs targeting Elkin1 and 164 found that knockdown of Elkin1 transcript resulted in a dramatic reduction in MA currents to 165 deflections up to 1000 nm (Figure 2A,B). These data suggested that Elkin1 contributes to 166 MA currents in melanoma cells. 167 168 Three human isoforms (representing splice variants) of Elkin1 have been identified: isoforms 169 1 and 3 (555 and 494 aa respectively), contain 6 predicted TM domains (Figure 2C). Isoform 170 2 (181 aa) does not contain any predicted TM domains and was not examined in this study.171 6We cloned hsElkin1-iso1 and hsElkin1-iso3 from WM266-4 cDNA and generated C-terminal 172 GFP fusion constructs. We confirmed the plasma membrane localisation of these two 17...