EFFECT OF ADENOSINE ON ISOPROTERENOL-INDUCED HYPERTROPHY IN VITRO. A PRELIMINARY STUDY

Persistent β1-adrenergic stimulation is thought to induce cardiac hypertrophy, alteration in calcium regulation and Cx43 over-expression. Adenosine is a negative feedback inhibitor of adrenergic stimulation in the heart, protecting it from toxic effects of overstimulation. The aim of our study evaluate the effects of adenosine administration on Cx43 and pCx43 expression and [Ca2+]i in Isoproterenol-treatedcardiomiocytesby usingH9c2 cells. Adenosine co-treatment reduced cellular hypertrophy, Cx43, pCx43 and CaMKII over-expression, and reducedintracellularCa2+ overload. These results suggest that the beneficial activity of adenosine on cardiomyocytes underlie the reduction of Cx43-dependent calcium overload and CaMKII over-expression, implying a potential therapeutic in cardiac hypertrophy

Role of connexin 43 in cardiovascular diseases

Gap junctions (GJs) channels provide the basis for intercellular communication in the cardiovascular system for maintenance of the normal cardiac rhythm, regulation of vascular tone and endothelial function as well as metabolic interchange between the cells. They allow the transfer of small molecules and may enable slow calcium wave spreading, transfer of "death" or of "survival" signals. In the cardiomyocytes the most abundant isoform is Connexin 43 (Cx43). Alterations in Cx43 expression and distribution were observed in myocardium disease; i.e. in hypertrophic cardiomyopathy, heart failure and ischemia. Recent reports suggest the presence of Cx43 in the mitochondria as well, at least in the inner mitochondrial membrane, where it plays a central role in ischemic preconditioning. In this review, the current knowledge on the relationship between the remodeling of cardiac gap junctions and cardiac diseases are summarized

Doxorubicin-Mediated Cardiotoxicity: Role of Mitochondrial Connexin 43

Doxorubicin is the highly effective anthracycline, but its clinical use is limited by cardiotoxicity and consequent dysfunction. It has been proposed that the etiology of this is related to mitochondrial dysfunction. Connexin 43 (Cx43), the principal protein building block of cardiac gap junctions and hemichannels, plays an important role in cardioprotection. Recent reports confirmed the presence of Cx43 in the mitochondria as well. In this study, the role of mitochondrial Cx43 was evaluated 3 or 6 h after Doxorubicin administration to the rat heart cell line H9c2. Pharmacological inhibition of Hsp90 demonstrated that the mitochondrial Cx43 conferred cardioprotection by reducing cytosolic and mitochondrial reactive oxygen species production, mitochondrial calcium overload and mitochondrial membrane depolarization and cytochrome c release. In conclusion, our study demonstrates that Cx43 plays an important role in the protection of cardiac cells from Doxorubicin-induced toxicity

Evaluation of heavy metals, cytotoxicity, and antioxidant activity of tomatoes grown in toxic muddy soils

This research studies tomatoes grown in polluted soils to ascertain their phytochemical and nutritive features. Pulp and seeds from tomatoes grown in muddy soils were analyzed for their antioxidant power and their toxicity because of the possibility that heavy metals were present in the soils. An antioxidant assay on methanol extracts was made by using DDPH, while an ABTS [2,2'-Azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid)] assay was used to evaluate the antioxidant activity of lipophilic fractions. Results of the antioxidant assay showed that the tomatoes maintained a high level of antioxidant activity especially in the lipophilic fractions which contain the most representative compounds. Cytotoxic activity was performed on HeLa, PDAC, and A375 cell lines by [3-(4,5-dimethylthiazol-2-yl)-2,5-phenyl-2H-tetrazolium bromide] (MTT) assay. Results showed that neither the seeds, nor the pulp, of the extracts was cytotoxic. The presence of heavy metals was evaluated by using spectroscopy of atomic absorption with a graphite oven. Test results show the absence of heavy metals and these results have an interesting scientific role because they provide useful information for promoting food safety

Role of intracellular and extracellular annexin A1 in migration and invasion of human pancreatic carcinoma cells

Background: Annexin A1 (ANXA1), a 37 kDa multifunctional protein, is over-expressed in tissues from patients of pancreatic carcinoma (PC) where the protein seems to be associated with malignant transformation and poor prognosis. Methods: The expression and localization of ANXA1 in MIA PaCa-2, PANC-1, BxPC-3 and CAPAN-2 cells were detected by Western Blotting and Immunofluorescence assay. Expression and activation of Formyl Peptide Receptors (FPRs) were shown through flow cytometry/PCR and FURA assay, respectively. To investigate the role of ANXA1 in PC cell migration and invasion, we performed in vitro wound-healing and matrigel invasion assays. Results: In all the analyzed PC cell lines, a huge expression and a variable localization of ANXA1 in sub-cellular compartments were observed. We confirmed the less aggressive phenotype of BxPC-3 and CAPAN-2 compared with PANC-1 and MIA PaCa-2 cells, through the evaluation of Epithelial-Mesenchymal Transition (EMT) markers. Then, we tested MIA PaCa-2 and PANC-1 cell migration and invasiveness rate which was inhibited by specific ANXA1 siRNAs. Both the cell lines expressed FPR-1 and -2. Ac2-26, an ANXA1 mimetic peptide, induced intracellular calcium release, consistent with FPR activation, and significantly increased cell migration/invasion rate. Interestingly, in MIA PaCa-2 cells we found a cleaved form of ANXA1 (33 kDa) that localizes at cellular membranes and is secreted outside the cells, as confirmed by MS analysis. The importance of the secreted form of ANXA1 in cellular motility was confirmed by the administration of ANXA1 blocking antibody that inhibited migration and invasion rate in MIA PaCa-2 but not in PANC-1 cells that lack the 33 kDa ANXA1 form and show a lower degree of invasiveness. Finally, the treatment of PANC-1 cells with MIA PaCa-2 supernatants significantly increased the migration rate of these cells. Conclusion: This study provides new insights on the role of ANXA1 protein in PC progression. Our findings suggest that ANXA1 protein could regulate metastasis by favouring cell migration/invasion intracellularly, as cytoskeleton remodelling factor, and extracellularly like FPR ligand

Cl-IB-MECA Inhibits Human Thyroid Cancer Cell Proliferation Independently of A3 Adenosine Receptor Activation

A3 adenosine receptor (A3AR) agonists have been reported to modulate cellular proliferation. This work was aimed to investigate the expression and the possible implication of A3AR in the human thyroid carcinomas. Normal thyroid tissue samples did not express A3 adenosine receptor, while primary thyroid cancer tissues expressed high level of A3AR, as determined by immunohistochemistry analysis. In human papillary thyroid carcinoma cell line, NPA, at concentrations > or =10 microM, the A3AR-selective agonist 2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide (Cl-IB-MECA) produced inhibition of cell growth, by blocking the G(1) cell cycle phase in a concentration- and time-dependent manner. This effect was well correlated with a reduction of protein expression of cyclins D1 and E2 after 24 hours of Cl-IB-MECA treatment. Moreover Cl-IB-MECA induced dephosphorylation of ERK1/2 in a time- and concentration-dependent manner, which in turn inhibits cell proliferation. The effect of Cl-IB-MECA was not prevented by A3AR antagonists, MRS1191 or MRS1523 or FA385. Furthermore, neither nucleoside transporter inhibitors, Dypiridamole and NBTI, nor the A1, A2A and A2B receptors antagonists were able to block the response to Cl-IB-MECA. Although Cl-IB-MECA has been shown to influence cell death and survival in other systems through an A3AR-mediated mechanism, in NPA cells the growth inhibition induced by micromolar concentrations of Cl-IB-MECA is not related to A3AR activation and hence that its effects on human papillary carcinoma cell line seem to be independent of the presence of this receptor subtype

MITOCHONDRIA AND CARDIOVASCULAR DISEASE: A BRIEF ACCOUNT

Mitochondria are the heart unit of the cardiac cell because they are involved in the ATP production and in the transfer to the contractile apparatus. Furthermore, mitochondria modulate Ca2+ homeostasis, manage redox status and regulate response to cellular and environmental stresses. Abnormalities in mitochondrial organelle structure and function have been observed in many cardiovascular diseases, such as ischemic cardiomyopathy, heart failure and stroke but also in drug-induced cardiomyopathies. This review summarizes the recent literature in this field

Inhibition of Connexin 43 translocation on mitochondria accelerates CoCl2-induced apoptotic response in a chemical model of hypoxia

Hypoxia is the basis of many myocardial conditions, and it can initiate cell death programs, among which apoptosis is well-known. Connexin 43 (Cx43), the major component of cardiomyocyte Gap Junctions, is important in cardioprotection. Cx43is involved in ischemia/reperfusion injury and ischemic preconditioning's protection in vitro; however, its role on cardiomyocyte under hypoxia is still unclear. Reports have shown that Cx43 is also located at the inner membrane of mitochondria where it has been implicated in enhanced ischemic preconditioning response. In this study, to evaluate the role of mitochondrial Cx43 in hypoxia, we used an in vitro model of chemical hypoxia induced by Cobalt chloride (CoCl2) in H9c2 cell line. CoCl2(50â\u80\u93100â\u80\u93150 μM) was administered for 3 or 6 h, alone or combined with Radicicol, that inhibits Cx43 translocation on mitochondria, to demonstrate the crucial role of mitochondrial Cx43 in the cardioprotection. In fact, reduction of Cx43 translocation on mitochondria increases mitochondrial ROS production, cytosolic and mitochondrial calcium overload and mitochondrial membrane depolarization, thus resulting in an increase of the triggering apoptotic pathway. In conclusion, our study demonstrates the involvement of mitochondrial Cx43 in the apoptotic process in a chemical hypoxia model and suggests that mitochondrial Cx43 plays a crucial role in cytoprotection