Search

Ribavirin is a guanosine analog with broad-spectrum antiviral activity against RNA viruses. Based on this, we aimed to show the anti-SARS-CoV-2 activity of this drug molecule via in vitro, in silico, and molecular techniques. Ribavirin showed antiviral activity in Vero E6 cells following SARS-CoV-2 infection, whereas the drug itself did not show any toxic effect over the concentration range tested. In silico analysis suggested that ribavirin has a broad-spectrum impact on SARS-CoV-2, acting at different viral proteins. According to the detailed molecular techniques, ribavirin was shown to decrease the expression of TMPRSS2 at both mRNA and protein levels 48 h after treatment. The suppressive effect of ribavirin in ACE2 protein expression was shown to be dependent on cell types. Finally, proteolytic activity assays showed that ribavirin also showed an inhibitory effect on the TMPRSS2 enzyme. Based on these results, we hypothesized that ribavirin may inhibit the expression of TMPRSS2 by modulating the formation of inhibitory G-quadruplex structures at the TMPRSS2 promoter. As a conclusion, ribavirin is a potential antiviral drug for the treatment against SARS-CoV-2, and it interferes with the effects of TMPRSS2 and ACE2 expression. Key words: COVID-19, in silico, in vitro, pathway analysis, drug. La ribavirine est un analogue de la guanosine avec une activite antivirale de large spectre contre les virus a ARN. Sur cette base, nous avons tente de montrer l'activite anti-SARS-CoV-2 de cette molecule pharmacologique a l'aide de techniques in vitro, in silico et moleculaires. La ribavirine a presente une activite antivirale contre les cellules Vero E6 a la suite d'une infection par le SARS-CoV-2 tandis que le medicament lui-meme n'avait aucun effet toxique dans la plage de concentrations evaluee. L'etude in silico a laisse entrevoir que la ribavirine a un effet a large spectre sur le SARS-CoV- 2, avec une action sur differentes proteines virales. A l'aide des techniques moleculaires detaillees, nous avons montre que la ribavirine entraine une diminution de l'expression de TMPRSS2 en taux d'ARNm comme de proteines 48 h apres son administration. Nous avons observe que l'effet suppresseur de la ribavirine sur l'expression d'ACE2 en proteines etait dependant du type de cellules. Enfin, les epreuves sur l'activite proteolytique ont montre que la ribavirine presentait aussi un effet inhibiteur sur l'enzyme TMPRSS2. De ces resultats, nous avons tire l'hypothese selon laquelle la ribavirine pourrait permettre d'inhiber l'expression de TMPRSS2 par l'intermediaire d'une modulation de la formation de structures inhibitrices G-quadruplex au niveau du promoteur de TMPRSS2. En conclusion, la ribavirine est un medicament antiviral eventuel pour le traitement contre le SARS-CoV-2, et elle interfere avec l'expression de TMPRSS2 et d'ACE2. Mots-cles: COVID-19, in silico, in vitro, etude de voie de signalisation, medicament., Introduction The coronavirus 2019 (COVID-19) pandemic represents the strongest global public health threat since the influenza outbreak in 1918 and has rapidly resulted in significant health and economic burdens worldwide [...]

Copyright of Journal of Ankara University Faculty of Medicine / Ankara Üniversitesi Tip Fakültesi Mecmuasi is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: In this study, it is aimed to examine the protective effect of magnolia extract (ME), a herbal material obtained from Magnolia Officinalis, which is claimed to have an important role in anti-inflammation, antioxidative stress and antiapoptosis, with increased reactive oxygen species (ROS) production due to aging and depolarized mitochondrial membrane potential (MMP) in cardiomyocytes and its suppressive effect on apoptosis and endoplasmic reticulum (ER) stress at the molecular level. Materials and Methods: In the study, an in vitro aging model was created using rat left ventricular cell line H9c2. H9c2 cells treated with D-galactose (D-Gal; 50 mg/mL) for 48 hours were incubated with 5 µM ME for 24 hours and their effects on ROS production and MMP depolarization in aged cardiomyocytes were examined. ROS and MMP measurements were performed under confocal microscopy using fluorescent dyes dichlorofluorescin diacetate (DCFDA) and carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP). With the ER- stress markers Calregulin and glucose-regulated protein 78, qRT-PCR measurements of the change in expression of the apoptosis marker equilibrative nucleoside transporter 1 after ME treatment were analyzed. Results: Incubation of aging-modeled cardiomyocytes with ME provides significant suppression of aging-related ROS production and regulation of depolarized MMP. In addition, we observed that ER-stress and apoptosis developed by mitochondrial dysfunction were suppressed by ME treatment, by examining the expressions of stress and apoptosis marker genes. Conclusion: Our findings show that Magnolia officinalis extract, known for its cardioprotective effects, can be applied as a new treatment approach in aging-related heart failure by regulating mitochondrion dysfunction that develops uncontrollably with cardiac aging at the functional and molecular level. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ankara University Faculty of Medicine / Ankara Üniversitesi Tip Fakültesi Mecmuasi is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Role of β3‐AR dysregulation, as either cardio‐conserving or cardio‐disrupting mediator, remains unknown yet. Therefore, we examined the molecular mechanism of β3‐AR activation in depressed myocardial contractility using a specific agonist CL316243 or using β3‐AR overexpressed cardiomyocytes. Since it has been previously shown a possible correlation between increased cellular free Zn2+ ([Zn2+]i) and depressed cardiac contractility, we first demonstrated a relation between β3‐AR activation and increased [Zn2+]i, parallel to the significant depolarization in mitochondrial membrane potential in rat ventricular cardiomyocytes. Furthermore, the increased [Zn2+]i induced a significant increase in messenger RNA (mRNA) level of β3‐AR in cardiomyocytes. Either β3‐AR activation or its overexpression could increase cellular reactive oxygen species (ROS) and reactive nitrogen species (RNS) levels, in line with significant changes in nitric oxide (NO)‐pathway, including increases in the ratios of pNOS3/NOS3 and pGSK‐3β/GSK‐3β, and PKG expression level in cardiomyocytes. Although β3‐AR activation induced depression in both Na+‐ and Ca2+‐currents, the prolonged action potential (AP) seems to be associated with a marked depression in K+‐currents. The β3‐AR activation caused a negative inotropic effect on the mechanical activity of the heart, through affecting the cellular Ca2+‐handling, including its effect on Ca2+‐leakage from sarcoplasmic reticulum (SR). Our cellular level data with β3‐AR agonism were supported with the data on high [Zn2+]i and β3‐AR protein‐level in metabolic syndrome (MetS)‐rat heart. Overall, our present data can emphasize the important deleterious effect of β3‐AR activation in cardiac remodeling under pathological condition, at least, through a cross‐link between β3‐AR activation, NO‐signaling, and [Zn2+]i pathways. Moreover, it is interesting to note that the recovery in ER‐stress markers with β3‐AR agonism in hyperglycemic cardiomyocytes is favored. Therefore, how long and to which level the β3‐AR agonism would be friend or become foe remains to be mystery, yet. [ABSTRACT FROM AUTHOR]

Abstract: Zn2+‐homoeostasis including free Zn2+ ([Zn2+]i) is regulated through Zn2+‐transporters and their comprehensive understanding may be important due to their contributions to cardiac dysfunction. Herein, we aimed to examine a possible role of Zn2+‐transporters in the development of heart failure (HF) via induction of ER stress. We first showed localizations of ZIP8, ZIP14 and ZnT8 to both sarcolemma and S(E)R in ventricular cardiomyocytes (H9c2 cells) using confocal together with calculated Pearson's coefficients. The expressions of ZIP14 and ZnT8 were significantly increased with decreased ZIP8 level in HF. Moreover, [Zn2+]i was significantly high in doxorubicin‐treated H9c2 cells compared to their controls. We found elevated levels of ER stress markers, GRP78 and CHOP/Gadd153, confirming the existence of ER stress. Furthermore, we measured markedly increased total PKC and PKCα expression and PKCα‐phosphorylation in HF. A PKC inhibition induced significant decrease in expressions of these ER stress markers compared to controls. Interestingly, direct increase in [Zn2+]i using zinc‐ionophore induced significant increase in these markers. On the other hand, when we induced ER stress directly with tunicamycin, we could not observe any effect on expression levels of these Zn2+ transporters. Additionally, increased [Zn2+]i could induce marked activation of PKCα. Moreover, we observed marked decrease in [Zn2+]i under PKC inhibition in H9c2 cells. Overall, our present data suggest possible role of Zn2+ transporters on an intersection pathway with increased [Zn2+]i and PKCα activation and induction of HF, most probably via development of ER stress. Therefore, our present data provide novel information how a well‐controlled [Zn2+]ivia Zn2+ transporters and PKCα can be important therapeutic approach in prevention/treatment of HF. [ABSTRACT FROM AUTHOR]

Role of β 3 -AR dysregulation, as either cardio-conserving or cardio-disrupting mediator, remains unknown yet. Therefore, we examined the molecular mechanism of β 3 -AR activation in depressed myocardial contractility using a specific agonist CL316243 or using β 3 -AR overexpressed cardiomyocytes. Since it has been previously shown a possible correlation between increased cellular free Zn 2+ ([Zn 2+ ] i ) and depressed cardiac contractility, we first demonstrated a relation between β 3 -AR activation and increased [Zn 2+ ] i , parallel to the significant depolarization in mitochondrial membrane potential in rat ventricular cardiomyocytes. Furthermore, the increased [Zn 2+ ] i induced a significant increase in messenger RNA (mRNA) level of β 3 -AR in cardiomyocytes. Either β 3 -AR activation or its overexpression could increase cellular reactive oxygen species (ROS) and reactive nitrogen species (RNS) levels, in line with significant changes in nitric oxide (NO)-pathway, including increases in the ratios of pNOS3/NOS3 and pGSK-3β/GSK-3β, and PKG expression level in cardiomyocytes. Although β 3 -AR activation induced depression in both Na + - and Ca 2+ -currents, the prolonged action potential (AP) seems to be associated with a marked depression in K + -currents. The β 3 -AR activation caused a negative inotropic effect on the mechanical activity of the heart, through affecting the cellular Ca 2+ -handling, including its effect on Ca 2+ -leakage from sarcoplasmic reticulum (SR). Our cellular level data with β 3 -AR agonism were supported with the data on high [Zn 2+ ] i and β 3 -AR protein-level in metabolic syndrome (MetS)-rat heart. Overall, our present data can emphasize the important deleterious effect of β 3 -AR activation in cardiac remodeling under pathological condition, at least, through a cross-link between β 3 -AR activation, NO-signaling, and [Zn 2+ ] i pathways. Moreover, it is interesting to note that the recovery in ER-stress markers with β 3 -AR agonism in hyperglycemic cardiomyocytes is favored. Therefore, how long and to which level the β 3 -AR agonism would be friend or become foe remains to be mystery, yet., (© 2019 Wiley Periodicals, Inc.)

Zn 2+ -homoeostasis including free Zn 2+ ([Zn 2+ ] i ) is regulated through Zn 2+ -transporters and their comprehensive understanding may be important due to their contributions to cardiac dysfunction. Herein, we aimed to examine a possible role of Zn 2+ -transporters in the development of heart failure (HF) via induction of ER stress. We first showed localizations of ZIP8, ZIP14 and ZnT8 to both sarcolemma and S(E)R in ventricular cardiomyocytes (H9c2 cells) using confocal together with calculated Pearson's coefficients. The expressions of ZIP14 and ZnT8 were significantly increased with decreased ZIP8 level in HF. Moreover, [Zn 2+ ] i was significantly high in doxorubicin-treated H9c2 cells compared to their controls. We found elevated levels of ER stress markers, GRP78 and CHOP/Gadd153, confirming the existence of ER stress. Furthermore, we measured markedly increased total PKC and PKCα expression and PKCα-phosphorylation in HF. A PKC inhibition induced significant decrease in expressions of these ER stress markers compared to controls. Interestingly, direct increase in [Zn 2+ ] i using zinc-ionophore induced significant increase in these markers. On the other hand, when we induced ER stress directly with tunicamycin, we could not observe any effect on expression levels of these Zn 2+ transporters. Additionally, increased [Zn 2+ ] i could induce marked activation of PKCα. Moreover, we observed marked decrease in [Zn 2+ ] i under PKC inhibition in H9c2 cells. Overall, our present data suggest possible role of Zn 2+ transporters on an intersection pathway with increased [Zn 2+ ] i and PKCα activation and induction of HF, most probably via development of ER stress. Therefore, our present data provide novel information how a well-controlled [Zn 2+ ] i via Zn 2+ transporters and PKCα can be important therapeutic approach in prevention/treatment of HF., (© 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)