Methylglyoxal accumulation de-regulates HoxA5 expression,thereby impairing angiogenesis in glyoxalase 1 knock-down mouse aortic endothelial cells

Impaired angiogenesis leads to long-term complications and is a major contributor of the high morbidity in patients with Diabetes Mellitus (DM). Methylglyoxal (MGO) is a glycolysis byproduct that accumulates in DM and is detoxified by the Glyoxalase 1 (Glo1). Several studies suggest that MGO contributes to vascular complications through mechanisms that remain to be elucidated. In this study we have clarified for the first time the molecular mechanism involved in the impairment of angiogenesis induced by MGO accumulation.Angiogenesis was evaluated in mouse aortic endothelial cells isolated from Glo1-knockdown mice (Glo1KD MAECs) and their wild-type littermates (WT MAECs). Reduction in Glo1 expression led to an accumulation of MGO and MGO-modified proteins and impaired angiogenesis of Glo1KD MAECs. Both mRNA and protein levels of the anti-angiogenic HoxA5 gene were increased in Glo1KD MAECs and its silencing improved both their migration and invasion. Nuclear NF-?B-p65 was increased 2.5-fold in the Glo1KD as compared to WT MAECs. Interestingly, NF-?B-p65 binding to HoxA5 promoter was also 2-fold higher in Glo1KD MAECs and positively regulated HoxA5 expression in MAECs. Consistent with these data, both the exposure to a chemical inhibitor of Glo1 “SpBrBzGSHCp2” (GI) and to exogenous MGO led to the impairment of migration and the increase of HoxA5 mRNA and NF-?B-p65 protein levels in microvascular mouse coronary endothelial cells (MCECs).This study demonstrates, for the first time, that MGO accumulation increases the antiangiogenic factor HoxA5 via NF-?B-p65, thereby impairing the angiogenic ability of endothelial cells.     

Human osteoblast-like cell proliferation induced by calcitonin-related peptides involves PKC activity

The calcitonin peptides [calcitonin (CT), calcitonin gene-related peptide (CGRP), amylin] share many biological actions, including activity on bone cells. In the present study, CT (10(-11) to 10(-9) M) stimulated [(3)H]thymidine incorporation in primary cultures of human osteoblasts (hOB), as already demonstrated for CGRP and amylin. RT-PCR analysis showed that the calcitonin receptor and the calcitonin receptor-like receptor are both expressed in hOB. In these cells, CT (10(-10) M) and amylin (10(-9) M), in contrast to CGRP (10(-8) M), did not increase cAMP production. All three peptides stimulated protein kinase C (PKC) activity. To evaluate PKC involvement in hOB proliferation, cells were incubated with phorbol 12,13-dibutyrate, a stimulator of PKC activity; cell proliferation was increased in a dose-dependent manner (EC(50) = 3.4 x 10(-8) M). Staurosporine (10(-9) M), a PKC inhibitor, blocked phorbol 12,13-dibutyrate-induced PKC activity and cell proliferation. Inhibition of PKC by staurosporine also counteracted the stimulatory effect of CT, CGRP, and amylin on hOB proliferation. From these data, it is deduced that the activation of PKC is important for hOB proliferation and that it is involved in the anabolic effect of CT peptides on bone.     

Short-term therapy with celecoxib and lansoprazole modulates Th1/ Th2 immune response in human gastric mucosa

Background: Selective cyclooxygenase‐2 (COX‐2) inhibitors and proton pump inhibitors may exert immune‐mediated effects in human gastric mucosa. T‐cell immune response plays a role in Helicobacter pylori‐induced pathogenesis. This study evaluated effects of celecoxib and lansoprazole on T‐helper (Th) 1 and Th2 immune response in human gastric mucosa. Methods: Dyspeptic patients with or without osteoarticular pain were given one of the following 4‐week therapies: celecoxib 200 mg, celecoxib 200 mg plus lansoprazole 30 mg, and lansoprazole 30 mg daily. Expression of COX‐2, T‐bet, and pSTAT6 and production of prostaglandin E₂ (PGE₂), interferon (IFN)‐γ, and interleukin (IL)‐4 were determined in gastric biopsies before and after therapy. Histology was evaluated. Results: Cyclooxygenase‐2 expression and PGE₂ production was higher, and Th1 signaling pathway was predominant in H. pylori‐infected vs. uninfected patients. T‐bet expression and IFN‐γ production increased, while STAT6 activation and IL‐4 production decreased following therapy with celecoxib and celecoxib plus lansoprazole, respectively. Th1 and Th2 signaling pathways down‐regulated after therapy with lansoprazole, and this was associated with an improvement of gastritis. Effect of therapy was not affected by H. pylori status. Conclusion: Celecoxib and lansoprazole modulate Th1/Th2 immune response in human gastric mucosa. The use of these drugs may interfere with long‐term course of gastritis.     

Purification of chondroitin precursor from Escherichia coli K4 fermentation broth using membrane processing

Recently the possibility of producing the capsular polysaccharide K4, a fructosylated chondroitin, in fed-batch experiments was assessed. In the present study, a novel downstream process to obtain chondroitin from Escherichia coli K4 fermentation broth was developed. The process is simple, scalable and economical. In particular, downstream procedures were optimized with a particular aim of purifying a product suitable for further chemical modifications, in an attempt to develop a biotechnological platform for chondroitin sulfate production. During process development, membrane devices (ultrafiltration/diafiltration) were exploited, selecting the right cassette cut-offs for different phases of purification. The operational conditions (cross-flow rate and transmembrane pressure) used for the process were determined on an ?KTA cross-flow instrument (GE Healthcare, USA), a lab-scale automatic tangential flow filtration system. In addition, parameters such as selectivity and throughput were calculated based on the analytical quantification of K4 and defructosylated K4, as well as the major contaminants. The complete downstream procedure yielded about 75% chondroitin with a purity higher than 90%.     

In vivo DNA gene electro-transfer: a systematic analysis of different electrical parameters

BACKGROUND: Intramuscular plasmid injection followed by electroporation is an efficient method for gene therapy or vaccination. Several protocols have been described that give good transduction levels with several reporter genes. METHODS: In this work we have explored the efficiency of gene delivery upon variation of the different electrical parameters such as pulse length frequency and voltage monitoring both on short- and long-term protein production. RESULTS: Having defined the best performing parameters, we have designed a short electric treatment that gives good levels of plasmid-encoded protein in different species such as mice, rabbits and monkeys.     

Expression of phospholipase C beta family isoenzymes in C2C12 myoblasts during terminal differentiation

In the present work, we have analyzed the expression and subcellular localization of all the members of inositide-specific phospholipase C (PLCbeta) family in muscle differentiation, given that nuclear PLCbeta1 has been shown to be related to the differentiative process. Cell cultures of C2C12 myoblasts were induced to differentiate towards the phenotype of myotubes, which are also indicated as differentiated C2C12 cells. By means of immunochemical and immunocytochemical analysis, the expression and subcellular localization of PLCbeta1, beta2, beta3, beta4 have been assessed. As further characterization, we investigated the localization of PLCbeta isoenzymes in C2C12 cells by fusing their cDNA to enhanced green fluorescent protein (GFP). In myoblast culture, PLCbeta4 was the most expressed isoform in the cytoplasm, whereas PLCbeta1 and beta3 exhibited a lesser expression in this cell compartment. In nuclei of differentiated myotube culture, PLCbeta1 isoform was expressed at the highest extent. A marked decrease of PLCbeta4 expression in the cytoplasm of differentiated C2C12 cells was detected as compared to myoblasts. No relevant differences were evidenced as regards the expression of PLCbeta3 at both cytoplasmatic and nuclear level, whilst PLCbeta2 expression was almost undetectable. Therefore, we propose that the different subcellular expression of these PLC isoforms, namely the increase of nuclear PLCbeta1 and the decrease of cytoplasmatic PLCbeta4, during the establishment of myotube differentiation, is related to a spatial-temporal signaling event, involved in myogenic differentiation. Once again the subcellular localization appears to be a key step for the diverse signaling activity of PLCbetas.     

A Highly Selective Oligopeptide Binding Protein from the Archaeon Sulfolobus Solfataricus

SSO1273 of Sulfolobus solfataricus was identified as a cell surface-bound protein by a proteomics approach. Sequence inspection of the genome revealed that the open reading frame of sso1273 is associated in an operon-like structure with genes encoding all the remaining components of a canonical protein-dependent ATP-binding cassette (ABC) transporter. sso1273 gene expression and SSO1273 protein accumulation on the cell surface were demonstrated to be strongly induced by the addition of a peptide mixture (tryptone) to the culture medium. The native protein was obtained in multimeric form, mostly hexameric, under the purification conditions used, and it was characterized as an oligopeptide binding protein, named S. solfataricus OppA (OppA_Ss). OppaA_Ss possesses typical sequence patterns required for glycosylphosphatidylinositol lipid anchoring, resulting in an N-linked glycoprotein with carbohydrate moieties likely composed of high mannose and/or hybrid complex carbohydrates. OppA_Ss specifically binds oligopeptides and shows a marked selectivity for the amino acid composition of substrates when assayed in complex peptide mixtures. Moreover, a truncated version of OppA_Ss, produced in recombinant form and including the putative binding domain, showed a low but significant oligopeptide binding activity.Sulfolobus solfataricus is an obligate aerobe that grows in hot and acidic environments either chemolithotrophically by oxidizing metal cations (Fe²⁺ or S⁻) or heterotrophically on simple sugars. It originates from a solfataric field with temperatures between 75°C and 90°C and pH values of 1.0 to 3.0 (9, 15). Within its environment, Sulfolobus can interact with a complex ecosystem consisting of a variety of primary producers and decomposers of organic matter. Moreover, biotopes such as the solfataric field of Sulfolobus contain decomposing materials of higher plants, including cellulose, starch, and proteinaceous compounds, that can act as potential carbon sources. Although S. solfataricus has been reported to grow on a wide variety of reduced organic compounds as the sole carbon and energy source (15), the nutrient utilization by this microorganism requires complex mechanisms of uptake and metabolism that are not yet well defined.Numerous efforts have been directed toward the identification of the carbohydrate utilization strategy in this hyperthermophilic archaeon (18, 23). The metabolic pathways for the degradation of a variety of sugars have been studied in detail and provide evidence that S. solfataricus predominantly uses binding-protein-dependent ABC transporters for the uptake of carbohydrate compounds (1, 2, 13).Archaeal ABC uptake systems are divided into two main classes: the carbohydrate (CUT) and the di-/oligopeptide uptake transporter classes (2). These transporter families use ATP hydrolysis to drive a unidirectional accumulation of solutes into the cytoplasm. The translocator components are composed of two integral membrane proteins, two peripheral membrane proteins that bind and hydrolyze ATP, and an extracellular substrate-binding protein (SBP). The SBP subunit captures and delivers the substrate to the translocon, and it is therefore considered to be one of the determinants of the transport specificity (2, 7, 10).All sequenced genomes of archaea and thermophilic bacteria contain a large number of genes encoding putative ABC transport systems involved in the uptake of organic solutes. The preference of hyperthermophiles for ABC-type transporters could be important for the survival strategy in their natural habitat. In the nutrient-poor environments, such as hydrothermal vents or sulfuric hot springs, in which these organisms thrive, ABC transporters have the advantage that they can scavenge solutes at very low concentrations due to the high binding affinities of their SBP components. Furthermore, these transporters can catalyze translocation at a high rate, resulting in high internal concentrations of solutes. In contrast, secondary transport systems exhibit lower binding affinities, which make these systems less suitable for growth in extreme environments.So far, attempts to predict the functional specificity of the ABC transporters using computational tools have been largely unsuccessful (2, 13, 20). For example, some characterized archaeal sugar transporters, based on the sequence identity and domain organization, were predicted to be di-/oligopeptide transporters (13, 20). These include the cellobiose/β-glucoside transporter system of Pyrococcus furiosus (20) and the maltose/maltodextrin and cellobiose/cello-oligomer transporters of S. solfataricus (13). However, genes encoding sugar-metabolizing enzymes are located in the vicinity of all these transport systems, suggesting that the location of the ABC operon can support the specific transport function.Like oligopeptide binding proteins, MalE and CbtA bind a broad range of polymeric substrates (13, 20). In contrast, sugar-binding proteins usually exhibit a narrow substrate specificity that is often limited to monosaccharides. Therefore, it may well be that the substrate binding pocket of CbtA and MalE resembles that of the OppA family of binding proteins that can accommodate a range of short and long oligopeptides.S. solfataricus contains 37 putative ABC transporters at the genome level (TransportDB, Genomic Comparisons of Membrane Transport systems [http://www.membranetransport.org/index.html]), but only a few of these systems have been functionally characterized. It is interesting that all of these are implicated in the uptake of mono-/oligosaccharides (1, 13, 20, 25).The present work describes the isolation and characterization of the first functional ABC substrate binding protein from S. solfataricus belonging to the di-/oligopeptide transporter family, named S. solfataricus OppA (OppA_Ss). We demonstrate that OppA_Ss is an outer-cell-surface-anchored protein and that its expression is highly induced in the presence of a source of peptides in the culture broth. Furthermore, in vitro substrate specificity studies using complex oligopeptide mixtures indicate that OppA_Ss is highly selective in peptide recognition.     

Modulation of the immune response induced by gene electrotransfer of a hepatitis C virus DNA vaccine in nonhuman primates

Induction of multispecific, functional CD4+ and CD8+ T cells is the immunological hallmark of acute self-limiting hepatitis C virus (HCV) infection in humans. In the present study, we showed that gene electrotransfer (GET) of a novel candidate DNA vaccine encoding an optimized version of the nonstructural region of HCV (from NS3 to NS5B) induced substantially more potent, broad, and long-lasting CD4+ and CD8+ cellular immunity than naked DNA injection in mice and in rhesus macaques as measured by a combination of assays, including IFN-gamma ELISPOT, intracellular cytokine staining, and cytotoxic T cell assays. A protocol based on three injections of DNA with GET induced a substantially higher CD4+ T cell response than an adenovirus 6-based viral vector encoding the same Ag. To better evaluate the immunological potency and probability of success of this vaccine, we have immunized two chimpanzees and have compared vaccine-induced cell-mediated immunity to that measured in acute self-limiting infection in humans. GET of the candidate HCV vaccine led to vigorous, multispecific IFN-gamma+CD8+ and CD4+ T lymphocyte responses in chimpanzees, which were comparable to those measured in five individuals that cleared spontaneously HCV infection. These data support the hypothesis that T cell responses elicited by the present strategy could be beneficial in prophylactic vaccine approaches against HCV.