Vidarabine, an Anti-Herpes Virus Agent, Protects Against the Development of Heart Failure With Relatively Mild Side-Effects on Cardiac Function in a Canine Model of Pacing-Induced Dilated Cardiomyopathy

Viral Infection and Antiviral Treatments in Ocular Pathologies

Ocular viral infections are common and widespread globally. These infectious diseases are a major cause of acute red eyes and vision loss. The eye and its nearby tissues can be infected by several viral agents, causing infections with a short course and limited ocular implications or a long clinical progression and serious consequences for the function and structure of the ocular region. Several surveillance studies underline the increased emergence of drug resistance among pathogenic viral strains, limiting treatment options for these infections. Currently, in the event of resistant infections, topical or systemic corticosteroids are useful in the management of associated immune reactions in the eye, which contribute to ocular dysfunction. Many cases of viral eye infections are misdiagnosed as being of bacterial origin. In these cases, therapy begins late and is not targeted at the actual cause of the infection, often leading to severe ocular compromises, such as corneal infiltrates, conjunctival scarring, and reduced visual acuity. The present study aims at a better understanding of the viral pathogens that cause eye infections, along with the treatment options available.

Novel Pyrazolo[3,4-d]pyrimidin-4-one Derivatives as Potential Antifungal Agents: Design, Synthesis, and Biological Evaluation

Plant pathogenic fungi seriously threaten agricultural production. There is an urgent need to develop novel fungicides with low toxicity and high efficiency. In this study, we designed and synthesized 44 pyrazolo[3,4-d]pyrimidin-4-one derivatives and evaluated them for their fungicidal activities. The bioassay data revealed that most of the target compounds possessed moderate to high in vitro antifungal activities. Especially compound g22 exhibited remarkable antifungal activity against Sclerotinia sclerotiorum with an EC₅₀ value of 1.25 mg/L, close to that of commercial fungicide boscalid (EC₅₀ = 0.96 mg/L) and fluopyram (EC₅₀ = 1.91 mg/L). Moreover, compound g22 possessed prominent protective activity against S. sclerotiorum in vivo for 24 h (95.23%) and 48 h (93.78%), comparable to positive control boscalid (24 h (96.63%); 48 h (93.23%)). Subsequent studies indicated that compound g22 may impede the growth and reproduction of S. sclerotiorum by affecting the morphology of mycelium, destroying cell membrane integrity, and increasing cell membrane permeability. In addition, the application of compound g22 did not injure the growth or reproduction of Italian bees. This study revealed that compound g22 is expected to be developed for efficient and safe agricultural fungicides.

Translationally controlled tumor protein (TCTP) plays a pivotal role in cardiomyocyte survival through a Bnip3-dependent mechanism

Prevention of cardiomyocyte death is an important therapeutic strategy for heart failure. In this study, we focused on translationally controlled tumor protein (TCTP), a highly conserved protein that is expressed ubiquitously in mammalian tissues, including heart. TCTP plays pivotal roles in survival of certain cell types, but its function in cardiomyocytes has not been examined. We aimed to clarify the role of TCTP in cardiomyocyte survival and the underlying mechanism. Here, we demonstrated that downregulation of TCTP with siRNA induced cell death of cardiomyocytes with apoptotic and autophagic features, accompanied with mitochondrial permeability transition pore (mPTP) opening. TCTP loss did not induce cell death of cardiac fibroblasts. Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (Bnip3) was found to mediate the TCTP-loss-induced cardiomyocyte death. In exploring the clinical significance of the TCTP expression in the heart, we found that DOX treatment markedly downregulated the protein expression of TCTP in cultured cardiomyocytes and in mouse heart tissue. Exogenous rescue of TCTP expression attenuated DOX-induced cardiomyocyte death. In mice, cardiomyocyte-specific overexpression of TCTP resulted in decreased susceptibility to DOX-induced cardiac dysfunction, accompanied with attenuated induction of Bnip3. Dihydroartemisinin, a pharmacological TCTP inhibitor, induced development of heart failure and cardiomyocyte death in control mice, but not in mice with cardiomyocyte-specific TCTP overexpression. Our findings revealed TCTP has a pivotal role in cardiomyocyte survival, at least in part through a Bnip3-dependent mechanism. TCTP could be considered as a candidate therapeutic target to prevent DOX-induced heart failure.

Intracoronary Gene Delivery of the Cytoprotective Factor Vascular Endothelial Growth Factor-B167 in Canine Patients with Dilated Cardiomyopathy: A Short-Term Feasibility Study

Dilated cardiomyopathy (DCM) is a myocardial disease of dogs and humans characterized by progressive ventricular dilation and depressed contractility and it is a frequent cause of heart failure. Conventional pharmacological therapy cannot reverse the progression of the disease and, in humans, cardiac transplantation remains the only option during the final stages of heart failure. Cytoprotective gene therapy with vascular endothelial growth factor-B₁₆₇ (VEGF-B₁₆₇) has proved an effective alternative therapy, halting the progression of the disease in experimental studies on dogs. The aim of this work was to test the tolerability and feasibility of intracoronary administration, under fluoroscopic guidance, of VEGF-B₁₆₇ carried by adeno-associated viral vectors in canine DCM patients. Ten patients underwent the gene delivery procedure. The intraoperative phase was well tolerated by all dogs. Clinical and echocardiographic assessments at 7- and 30-days post-procedure showed stable conditions compared to the pre-procedure phase. The results of this work indicate that intracoronary VEGF-B₁₆₇ gene delivery is feasible and tolerated in dogs with DCM. Further monitoring/investigations are ongoing to evaluate the effects of this therapy on disease progression.

Usefulness of Exchanged Protein Directly Activated by cAMP (Epac)1-Inhibiting Therapy for Prevention of Atrial and Ventricular Arrhythmias in Mice

BACKGROUND

It has been suggested that protein directly activated by cAMP (Epac), one of the downstream signaling molecules of β-adrenergic receptor (β-AR), may be an effective target for the treatment of arrhythmia. However, there have been no reports on the anti-arrhythmic effects or cardiac side-effects of Epac1 inhibitors in vivo. Methods and Results: In this study, the roles of Epac1 in the development of atrial and ventricular arrhythmias are examined. In addition, we examined the usefulness of CE3F4, an Epac1-selective inhibitor, in the treatment of the arrhythmias in mice. In Epac1 knockout (Epac1-KO) mice, the duration of atrial fibrillation (AF) was shorter than in wild-type mice. In calsequestrin2 knockout mice, Epac1 deficiency resulted in a reduction of ventricular arrhythmia. In both atrial and ventricular myocytes, sarcoplasmic reticulum (SR) Ca²⁺ leak, a major trigger of arrhythmias, and spontaneous SR Ca²⁺ release (SCR) were attenuated in Epac1-KO mice. Consistently, CE3F4 treatment significantly prevented AF and ventricular arrhythmia in mice. In addition, the SR Ca²⁺ leak and SCR were significantly inhibited by CE3F4 treatment in both atrial and ventricular myocytes. Importantly, cardiac function was not significantly affected by a dosage of CE3F4 sufficient to exert anti-arrhythmic effects.

CONCLUSIONS

These findings indicated that Epac1 is involved in the development of atrial and ventricular arrhythmias. CE3F4, an Epac1-selective inhibitor, prevented atrial and ventricular arrhythmias in mice.

Vidarabine, an anti-herpesvirus agent, prevents catecholamine-induced arrhythmias without adverse effect on heart function in mice

Sympathetic activation causes clinically important arrhythmias including atrial fibrillation (AF) and ventricular tachyarrhythmia. Although the usefulness of β-adrenergic receptor blockade therapy is widely accepted, its multiple critical side effects often prevent its initiation or continuation. The aim of this study is to determine the advantages of vidarabine, an adenylyl cyclase (AC)-targeted anti-sympathetic agent, as an alternative treatment for arrhythmia. We found that vidarabine, which we identified as a cardiac AC inhibitor, consistently shortens AF duration and reduces the incidence of sympathetic activation-induced ventricular arrhythmias. In atrial and ventricular myocytes, vidarabine inhibits adrenergic receptor stimulation-induced RyR2 phosphorylation, sarcoplasmic reticulum (SR) Ca²⁺ leakage, and spontaneous Ca²⁺ release from SR, the last of which has been considered as a potential arrhythmogenic trigger. Moreover, vidarabine also inhibits sympathetic activation-induced reactive oxygen species (ROS) production in cardiac myocytes. The pivotal role of vidarabine's inhibitory effect on ROS production with regard to its anti-arrhythmic property has also been implied in animal studies. In addition, as expected, vidarabine exerts an inhibitory effect on AC function, which is more potent in the heart than elsewhere. Indexes of cardiac function including ejection fraction and heart rate were not affected by a dosage of vidarabine sufficient to exert an anti-arrhythmic effect. These findings suggest that vidarabine inhibits catecholamine-induced AF or ventricular arrhythmia without deteriorating cardiac function in mice.