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Hydrogels from self-assembling ionic complementary peptides have been receiving much interest from the scientific community as mimetics of the extracellular matrix that can offer three-dimensional support for cell growth or become vehicles for the delivery of stem cells or drugs. These scaffolds have also been proposed as bone substitutes for small defects as they promote beneficial effects on human osteoblasts. In order to develop a novel bioactive titanium implant, we propose the introduction of a layer of ionic-complementary self-assembling peptides (EAbuK) on Ti whose surface has been previously sandblasted and acid etched. The peptide layer is anchored to the metal by covalent functionalization of titania with self-assembling sequences. The peptide layer has also been enriched by the insulin-like growth factor-1 incorporated to the layer and/or a conjugate obtained by chemoselective ligation between EAbuK and a sequence of 25 residues containing four GRGDSP motifs per chain. X-ray photoelectron spectroscopy studies confirmed a change in the surface composition in agreement with the proposed decorations. An evaluation of the contact angle showed a substantial change in wettability induced by the peptide layer. The human osteoblast adhesion and proliferation assays showed an increase in adhesion for the surfaces enriched with conjugate at a concentration of 3.8 × 10−7 m and an enhanced proliferation for samples enriched with insulin-like growth factor-1 at the highest concentration tested (2.1 × 10−5 m). Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background and Purpose: Adenosine A(2B) receptors regulate several physiological enteric functions. However, their role in the pathophysiology of intestinal dysmotility associated with inflammation has not been elucidated. Hence, we investigated the expression of A2B receptors in rat colon and their role in the control of cholinergic motility in the presence of bowel inflammation.Experimental Approach: Colitis was induced by 2,4-dinitrobenzenesulfonic acid (DNBS). Colonic A(2B) receptor expression and localization were examined by RT-PCR and immunofluorescence. The interaction between A(2B) receptors and adenosine deaminase was assayed by immunoprecipitation. The role of A(2B) receptors in the control of colonic motility was examined in functional experiments on longitudinal muscle preparations (LMPs).Key Results: A(2B) receptor mRNA was present in colon from both normal and DNBS-treated rats but levels were increased in the latter. A(2B) receptors were predominantly located in the neuromuscular layer, but, in the presence of colitis, were increased mainly in longitudinal muscle. Functionally, the A(2B) receptor antagonist MRS 1754 enhanced both electrically-evoked and carbachol-induced cholinergic contractions in normal LMPs, but was less effective in inflamed tissues. The A(2B) receptor agonist NECA decreased colonic cholinergic motility, with increased efficacy in inflamed LMP. Immunoprecipitation and functional tests revealed a link between A(2B) receptors and adenosine deaminase, which colocalize in the neuromuscular compartment.Conclusions and Implications: Under normal conditions, endogenous adenosine modulates colonic motility via A2B receptors located in the neuromuscular compartment. In the presence of colitis, this inhibitory control is impaired due to a link between A2B receptors and adenosine deaminase, which catabolizes adenosine, thus preventing A(2B) receptor activation. [ABSTRACT FROM AUTHOR]

Background and Purpose Adenosine A2B receptors regulate several physiological enteric functions. However, their role in the pathophysiology of intestinal dysmotility associated with inflammation has not been elucidated. Hence, we investigated the expression of A2B receptors in rat colon and their role in the control of cholinergic motility in the presence of bowel inflammation. Experimental Approach Colitis was induced by 2,4-dinitrobenzenesulfonic acid (DNBS). Colonic A2B receptor expression and localization were examined by RT-PCR and immunofluorescence. The interaction between A2B receptors and adenosine deaminase was assayed by immunoprecipitation. The role of A2B receptors in the control of colonic motility was examined in functional experiments on longitudinal muscle preparations (LMPs). Key Results A2B receptor mRNA was present in colon from both normal and DNBS-treated rats but levels were increased in the latter. A2B receptors were predominantly located in the neuromuscular layer, but, in the presence of colitis, were increased mainly in longitudinal muscle. Functionally, the A2B receptor antagonist MRS 1754 enhanced both electrically-evoked and carbachol-induced cholinergic contractions in normal LMPs, but was less effective in inflamed tissues. The A2B receptor agonist NECA decreased colonic cholinergic motility, with increased efficacy in inflamed LMP. Immunoprecipitation and functional tests revealed a link between A2B receptors and adenosine deaminase, which colocalize in the neuromuscular compartment. Conclusions and Implications Under normal conditions, endogenous adenosine modulates colonic motility via A2B receptors located in the neuromuscular compartment. In the presence of colitis, this inhibitory control is impaired due to a link between A2B receptors and adenosine deaminase, which catabolizes adenosine, thus preventing A2B receptor activation. [ABSTRACT FROM AUTHOR]

Background and Purpose: Adenosine A(3) receptors mediate beneficial effects in experimental colitis, but their involvement in enteric neuromuscular functions during bowel inflammation is undetermined. This study investigated the regulatory role of A(3) receptors on colonic motility in the presence of experimental colitis.Experimental Approach: Colitis was induced in rats by 2,4-dinitrobenzenesulfonic acid. A(3) receptors and adenosine deaminase (ADA, adenosine catabolic enzyme) mRNA were examined by RT-PCR. Tissue distribution of A(3) receptors was detected by confocal immunofluorescence. The effects of 2,3-ethyl-4,5-dipropyl-6-phenylpyridine-3-thiocarboxylate-5-carboxylate (MRS1523) (MRS, A(3) receptor antagonist), 2-chloro-N(6) -(3-iodobenzyl)-adenosine-5'-N-methyluronamide (2Cl-IB-MECA) (CIB, A(3) receptor agonist), dipyridamole (DIP, adenosine transport inhibitor) and ADA were assayed on contractile responses evoked by electrical stimulation (ES) or carbachol in colonic longitudinal muscle preparations (LMP).Key Results: RT-PCR showed A(3) receptors and ADA mRNA in normal colon and their increased level in inflamed tissues. Immunofluorescence showed a predominant distribution of A(3) receptors in normal myenteric ganglia and an increased density during colitis. MRS enhanced ES-induced cholinergic contractions in normal LMP, but was less effective in inflamed tissues. After pretreatment with dipyridamole plus ADA, to reduce extracellular adenosine, CIB decreased cholinergic motor responses of normal LMP to ES, with enhanced efficacy in inflamed LMP. A(3) receptor ligands did not affect carbachol-induced contractions in LMP from normal or inflamed colon.Conclusions and Implications: Normally, adenosine modulated colonic cholinergic motility via activation of A(3) receptors in the myenteric plexus. A(3) receptor-mediated tonic inhibitory control by adenosine was impaired in inflamed bowel, despite increased density of functioning and pharmacologically recruitable A(3) receptors. [ABSTRACT FROM AUTHOR]

A protective role of the transient potential vanilloid receptor 1 (TRPV1) in intestinal inflammation induced by dinitrobenzene sulphonic acid (DNBS) has been recently demonstrated. Curcumin, the major active component of turmeric, is also able to prevent and ameliorate the severity of the damage in DNBS-induced colitis. We evaluated the possibility that curcumin (45 mg kg−1 day p.o. for 2 days before and 5 days after the induction of colitis) was able to reduce DNBS-induced colitis in mice, by acting as a TRPV1 agonist. Macroscopic damage score, histological damage score and colonic myeloperoxidase (MPO) activity were significantly lower (by 71%, 65% and 73%, respectively; P < 0.01), in animals treated with curcumin compared with untreated animals. Capsazepine (30 mg kg−1, i.p.), a TRPV1 receptor antagonist, completely abolished the protective effects of curcumin. To extend these data in vitro, Xenopus oocytes expressing rat TRPV1 were examined. Capsaicin-evoked currents (3.3 μmol L−1) disappeared subsequent either to removal of the agonist or subsequent to the addition of capsazepine. However, curcumin (30 μmol L−1) was ineffective both as regard direct modification of cell membrane currents and as regard interference with capsaicin-mediated effects. As sensitization of the TRPV1 receptor by mediators of inflammation in damaged tissues has been shown previously, our results suggest that in inflamed, but not in normal tissue, curcumin can interact with the TRPV1 receptor to mediate its protective action in DNBS-induced colitis. [ABSTRACT FROM AUTHOR]

1 The role of substance P and its high affinity neurokinin-1 receptor in colitis has not been fully elucidated. We assessed the participation of neurokinin-1 receptor in colitis using the 2,4,6,-trinitrobenzensulphonic add and dextran sulphate-induced animal models of colitis and genetically-engineered, neurokinin-1 receptor-deficient mice. 2 Clinical signs, macroscopic and histologic damage associated with 2,4,6,-trinitrobenzensulphonic acid (12 days) and dextran sulphate (5 days) colitis were more severe in neurokinin-1 deficient than in wild-type mice, while immuno reactivities for epidermal growth factor and its receptor were similar in the colon of both mice strains before and after colitis. 3 Substance P. dose-dependently induced intestinal fibroblast proliferation and enhanced epidermal growth factor-induced proliferation in intestinal fibroblasts isolated from wild-type, but not from neurokinin-1 receptor deficient mice. 4 Substance P-induced intestinal fibroblast proliferation required the presence of epidermal growth factor receptor with kinase activity. Furthermore, substance P induced epidermal growth factor tyrosine phosphorylation and activation in normal intestinal fibroblasts. 5 Our results indicate that in mice lacking the neurokinin-I receptor, substance P plays a protective role in prolonged experimental colitis. [ABSTRACT FROM AUTHOR]

Background & Aims: MicroRNAs (miRNAs) have been involved in hepatocarcinogenesis, but little is known on their role in the progression of chronic viral hepatitis. Aim of this study was to identify miRNA signatures associated with stages of disease progression in patients with chronic viral hepatitis., Methods: MiRNA expression profile was investigated in liver biopsies from patients with chronic viral hepatitis and correlated with clinical, virological and histopathological features. Relevant miRNAs were further investigated., Results: Most of the significant changes in miRNA expression were associated with liver fibrosis stages and included the significant up-regulation of a group of miRNAs that were demonstrated to target the master regulators of epithelial-mesenchymal transition ZEB1 and ZEB2 and involved in the preservation of epithelial cell differentiation, but also in cell proliferation and fibrogenesis. In agreement with miRNA data, immunostaining of liver biopsies showed that expression of the epithelial marker E-cadherin was maintained in severe fibrosis/cirrhosis while expression of ZEBs and other markers of epithelial-mesenchymal transition were low or absent. Severe liver fibrosis was also significantly associated with the down-regulation of miRNAs with antiproliferative and tumour suppressor activity. Similar changes in miRNA and target gene expression were demonstrated along with disease progression in a mouse model of carbon tetrachloride (CCl4)-induced liver fibrosis, suggesting that they might represent a general response to liver injury., Conclusion: Chronic viral hepatitis progression is associated with the activation of miRNA pathways that promote cell proliferation and fibrogenesis, but preserve the differentiated hepatocyte phenotype., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)