Strain‐Based In Situ Study of Anion and Cation Insertion into Porous Carbon Electrodes with Different Pore Sizes

The expansion of porous carbon electrodes in a room temperature ionic liquid (RTIL) is studied using in situ atomic force microscopy (AFM). The effect of carbon surface area and pore size/pore size distribution on the observed strain profile and ion kinetics is examined. Additionally, the influence of the potential scan rate on the strain response is investigated. By analyzing the strain data at various potential scan rates, information on ion kinetics in the different carbon materials is obtained. Molecular dynamics (MD) simulations are performed to compare with and provide molecular insights into the experimental results; this is the first MD work investigating the pressure exerted on porous electrodes under applied potential in a RTIL electrolyte. Using MD, the pressure exerted on the pore wall is calculated as a function of potential/charge for both a micropore (1.2 nm) and a mesopore (7.0 nm). The shape of the calculated pressure profile matches closely with the strain profiles observed experimentally.     

Role of D-Limonene in Autophagy Induced by Bergamot Essential Oil in SH-SY5Y Neuroblastoma Cells

Bergamot (Citrus bergamia, Risso et Poiteau) essential oil (BEO) is a well characterized, widely used plant extract. BEO exerts anxiolytic, analgesic and neuroprotective activities in rodents through mechanisms that are only partly known and need to be further investigated. To gain more insight into the biological effects of this essential oil, we tested the ability of BEO (0.005–0.03%) to modulate autophagic pathways in human SH-SY5Y neuroblastoma cells. BEO-treated cells show increased LC3II levels and appearance of dot-like formations of endogenous LC3 protein that colocalize with the lysosome marker LAMP-1. Autophagic flux assay using bafilomycin A1 and degradation of the specific autophagy substrate p62 confirmed that the observed increase of LC3II levels in BEO-exposed cells is due to autophagy induction rather than to a decreased autophagosomal turnover. Induction of autophagy is an early and not cell-line specific response to BEO. Beside basal autophagy, BEO also enhanced autophagy triggered by serum starvation and rapamycin indicating that the underlying mechanism is mTOR independent. Accordingly, BEO did not affect the phosphorylation of ULK1 (Ser757) and p70^S6K (Thr389), two downstream targets of mTOR. Furthermore, induction of autophagy by BEO is beclin-1 independent, occurs in a concentration-dependent manner and is unrelated to the ability of BEO to induce cell death. In order to identify the active constituents responsible for these effects, the two most abundant monoterpenes found in the essential oil, d-limonene (125–750 µM) and linalyl acetate (62.5–375 µM), were individually tested at concentrations comparable to those found in 0.005–0.03% BEO. The same features of stimulated autophagy elicited by BEO were reproduced by d-limonene, which rapidly increases LC3II and reduces p62 levels in a concentration-dependent manner. Linalyl acetate was ineffective in replicating BEO effects; however, it greatly enhanced LC3 lipidation triggered by d-limonene.     

Catestatin Increases the Expression of Anti-Apoptotic and Pro-Angiogenetic Factors in the Post-Ischemic Hypertrophied Heart of SHR

Background

In the presence of comorbidities the effectiveness of many cardioprotective strategies is blunted. The goal of this study was to assess in a hypertensive rat model if the early reperfusion with anti-hypertensive and pro-angiogenic Chromogranin A-derived peptide, Catestatin (CST:hCgA_352–372; CST-Post), protects the heart via Reperfusion-Injury-Salvage-Kinases (RISK)-pathway activation, limiting infarct-size and apoptosis, and promoting angiogenetic factors (e.g., hypoxia inducible factor, HIF-1α, and endothelial nitric oxide synthase, eNOS, expression).

Methods and Results

The effects of CST-Post on infarct-size, apoptosis and pro-angiogenetic factors were studied in isolated hearts of spontaneously hypertensive rats (SHR), which underwent the following protocols: (a) 30-min ischemia and 120-min reperfusion (I/R); (b) 30-min ischemia and 20-min reperfusion (I/R-short), both with and without CST-Post (75 nM for 20-min at the beginning of reperfusion). In unprotected Wistar-Kyoto hearts, used as normal counterpart, infarct-size resulted smaller than in SHR. CST-Post reduced significantly infarct-size and improved post-ischemic cardiac function in both strains. After 20-min reperfusion, CST-Post induced S-nitrosylation of calcium channels and phosphorylation of RISK-pathway in WKY and SHR hearts. Yet specific inhibitors of the RISK pathway blocked the CST-Post protective effects against infarct in the 120-min reperfusion groups. Moreover, apoptosis (evaluated by TUNEL, ARC and cleaved caspase) was reduced by CST-Post. Importantly, CST-Post increased expression of pro-angiogenetic factors (i.e., HIF-1α and eNOS expression) after two-hour reperfusion.

Conclusions

CST-Post limits reperfusion damages and reverses the hypertension-induced increase of I/R susceptibility. Moreover, CST-Post triggers antiapoptotic and pro-angiogenetic factors suggesting that CST-Post can be used as an anti-maladaptive remodeling treatment.     

Down-modulation of SEL1L,an Unfolded Protein Response and Endoplasmic Reticulum-associated Degradation Protein,Sensitizes Glioma Stem Cells to the Cytotoxic Effect of Valproic Acid

Valproic acid (VPA), an histone deacetylase inhibitor, is emerging as a promising therapeutic agent for the treatments of gliomas by virtue of its ability to reactivate the expression of epigenetically silenced genes. VPA induces the unfolded protein response (UPR), an adaptive pathway displaying a dichotomic yin yang characteristic; it initially contributes in safeguarding the malignant cell survival, whereas long-lasting activation favors a proapoptotic response. By triggering UPR, VPA might tip the balance between cellular adaptation and programmed cell death via the deregulation of protein homeostasis and induction of proteotoxicity. Here we aimed to investigate the impact of proteostasis on glioma stem cells (GSC) using VPA treatment combined with subversion of SEL1L, a crucial protein involved in homeostatic pathways, cancer aggressiveness, and stem cell state maintenance. We investigated the global expression of GSC lines untreated and treated with VPA, SEL1L interference, and GSC line response to VPA treatment by analyzing cell viability via MTT assay, neurosphere formation, and endoplasmic reticulum stress/UPR-responsive proteins. Moreover, SEL1L immunohistochemistry was performed on primary glial tumors. The results show that (i) VPA affects GSC lines viability and anchorage-dependent growth by inducing differentiative programs and cell cycle progression, (ii) SEL1L down-modulation synergy enhances VPA cytotoxic effects by influencing GSCs proliferation and self-renewal properties, and (iii) SEL1L expression is indicative of glioma proliferation rate, malignancy, and endoplasmic reticulum stress statuses. Targeting the proteostasis network in association to VPA treatment may provide an alternative approach to deplete GSC and improve glioma treatments.     

Quorum-Sensing Regulation of Constitutive Plantaricin by Lactobacillus plantarum Strains under a Model System for Vegetables and Fruits

This study aimed at investigating the regulatory system of bacteriocin synthesis by Lactobacillus plantarum strains in vegetables and fruits in a model system. Sterile and neutralized cell-free supernatant (CFS) from L. plantarum strains grown in MRS broth showed in vitro antimicrobial activities toward various indicator strains. The highest activity was that of L. plantarum C2. The antimicrobial activity was further assayed on vegetable and fruit agar plates (solid conditions) and in juices (liquid conditions). A regulatory mechanism of bacteriocin synthesis via quorum sensing was hypothesized. The synthesis of antimicrobial compounds seemed to be constitutive under solid conditions of growth on vegetable and fruit agar plates. In contrast, it depended on the size of the inoculum when L. plantarum C2 was grown in carrot juice. Only the inoculum of ca. 9.0 log CFU ml⁻¹ produced detectable activity. The genes plnA, plnEF, plnG, and plnH were found in all L. plantarum strains. The genes plnJK and plnN were detected in only three or four strains. Reverse-phase high-performance liquid chromatography purification and mass spectrometry analysis revealed the presence of a mixture of eight peptides in the most active fraction of the CFS from L. plantarum C2. Active peptides were encrypted into bacteriocin precursors, such as plantaricins PlnJ/K and PlnH and PlnG, which are involved in the ABC transport system. A real-time PCR assay showed an increase in the expression of plnJK and plnG during growth of L. plantarum C2 in carrot juice.     

Ser-His catalyses the formation of peptides and PNAs

The dipeptide seryl-histidine (Ser-His) catalyses the condensation of esters of amino acids, peptide fragments, and peptide nucleic acid (PNA) building blocks, bringing to the formation of peptide bonds. Di-, tri- or tetra-peptides can be formed with yields that vary from 0.5% to 60% depending on the nature of the substrate and on the conditions. Other simpler peptides as Gly-Gly, or Gly-Gly-Gly are also effective, although less efficiently. We discuss the results from the viewpoint of primitive chemistry and the origin of long macromolecules by stepwise fragment condensations.     

Hyperglycemia in streptozotocin-induced diabetes leads to persistent inflammation and tissue damage following uveitis due to reduced levels of ciliary body heme oxygenase-1

This study investigated the heme oxygenase-1 (HO-1) and the endotoxin-induced uveitis (EIU) in diabetic streptozotocin (STZ)-hyperglycemic rats. STZ-hyperglycemic rats had impaired levels of the enzyme HO-1 within the ciliary bodies if compared with the nondiabetic rats. STZ-hyperglycemic rats also predisposed the eye to produce high levels of both the cytokines IL-1beta and CXCL8. Subsequent EIU further and significantly (P < .01) increased the cytokines production, an effect partly prevented by hemin treatment. Most importantly, hemin, an inducer of heme oxygenase expression and activity, recovered the huge number of infiltrated polymorphonuclear leukocytes PMN within the ciliary bodies associated with STZ-hyperglycemic state and EIU damage. Impairment of the stress-sensitive enzyme HO-1 in STZ-hyperglycemic rats increases and prolongs the inflammatory response to EIU.     

Speciation of phytate ion in aqueous solution. Sequestration of magnesium and calcium by phytate at different temperatures and ionic strengths, in NaCl(aq)

The formation and stability of Mg(2+) and Ca(2+)-phytate complexes was studied potentiometrically using an ISE-H(+) electrode. Measurements were performed at 10 degrees C and 25 degrees C in NaCl(aq) in the ionic strength range 0.1< or =I< or =0.75 mol L(-1). For both magnesium and calcium systems, the formation of ten M(i)PhyH(j)((12-2i-j)-) species was observed in the range 3< or =pH< or =7 with i=1, 2, 3 and j=3, 4, 5 (and i=3, j=2). These species are quite stable; here we report for example some quantitative data for the species Ca(i)PhyH(3)((9-2i)-), i=1, 2, 3 (equilibrium iCa(2+)+H(j)Phy((12-j)-)=Ca(i)PhyH(j)((12-j-2i)-): K(ij)) at I=0.25 mol L(-1) and t=25 degrees C: logK(13)=3.42, logK(23)=6.47 and logK(33)=9.41. The speciation of the Ca(2+)-phytate system was also checked by ISE-Ca(2+) measurements. Dependence on ionic strength was modeled using a simple Debye-Hückel type equation and formation constants were calculated at infinite dilution. The stability constants of complexes formed at pH>7 were estimated using an empirical predictive equation. The sequestering ability of phytate towards Mg(2+) and Ca(2+) was calculated in different experimental conditions and compared with those of other chelating agents.     

Eph/ephrins and N-cadherin coordinate to control the pattern of sympathetic ganglia

Previous studies have suggested that the segmental pattern of neural-crest-derived sympathetic ganglia arises as a direct result of signals that restrict neural crest cell migratory streams through rostral somite halves. We recently showed that the spatiotemporal pattern of chick sympathetic ganglia formation is a two-phase process. Neural crest cells migrate laterally to the dorsal aorta, then surprisingly spread out in the longitudinal direction, before sorting into discrete ganglia. Here, we investigate the function of two families of molecules that are thought to regulate cell sorting and aggregation. By blocking Eph/ephrins or N-cadherin function, we measure changes in neural crest cell migratory behaviors that lead to alterations in sympathetic ganglia formation using a recently developed sagittal slice explant culture and 3D confocal time-lapse imaging. Our results demonstrate that local inhibitory interactions within inter-ganglionic regions, mediated by Eph/ephrins, and adhesive cell-cell contacts at ganglia sites, mediated by N-cadherin, coordinate to sculpt discrete sympathetic ganglia.