The identification of novel drug targets is needed to improve the outcomes of heart failure (HF). G-protein-coupled receptors (GPCRs) represent the largest family of targets for already approved drugs, thus providing an opportunity for drug repurposing. Here, we aimed (i) to investigate the differential expressions of 288 cardiac GPCRs via droplet digital PCR (ddPCR) and bulk RNA sequencing (RNAseq) in a rat model of left ventricular pressure-overload; (ii) to compare RNAseq findings with those of ddPCR; and (iii) to screen and test for novel, translatable GPCR drug targets in HF. Male Wistar rats subjected to transverse aortic constriction (TAC, n = 5) showed significant systolic dysfunction vs. sham operated animals (SHAM, n = 5) via echocardiography. In TAC vs. SHAM hearts, RNAseq identified 69, and ddPCR identified 27 significantly differentially expressed GPCR mRNAs, 8 of which were identified using both methods, thus showing a correlation between the two methods. Of these, Prostaglandin-F2α-receptor (Ptgfr) was further investigated and localized on cardiomyocytes and fibroblasts in murine hearts via RNA-Scope. Antagonizing Ptgfr via AL-8810 reverted angiotensin-II-induced cardiomyocyte hypertrophy in vitro. In conclusion, using ddPCR as a novel screening method, we were able to identify GPCR targets in HF. We also show that the antagonism of Ptgfr could be a novel target in HF by alleviating cardiomyocyte hypertrophy.

Background and Purpose: Cardioprotective miRNAs (protectomiRs) are promising therapeutic tools. Here, we aimed to identify protectomiRs in a translational porcine model of acute myocardial infarction (AMI) and to validate their cardiocytoprotective effect.Experimental Approach: ProtectomiR candidates were selected after systematic analysis of miRNA expression changes in cardiac tissue samples from a closed‐chest AMI model in pigs subjected to sham operation, AMI and ischaemic preconditioning, postconditioning or remote preconditioning, respectively. Cross‐species orthologue protectomiR candidates were validated in simulated ischaemia–reperfusion injury (sI/R) model of isolated rat ocardiomyocytes and in human AC16 cells as well. For miR‐450a, we performed target prediction and analysed the potential mechanisms of action by GO enrichment and KEGG pathway analysis.Key Results: Out of the 220 detected miRNAs, four were up‐regulated and 10 were down‐regulated due to all three conditionings versus AMI. MiR‐450a and miR‐451 mimics at 25 nM were protective in rat cardiomyocytes, and miR‐450a showed protection in human cardiomyocytes as well. MiR‐450a has 3987 predicted mRNA targets in pigs, 4279 in rats and 8328 in humans. Of these, 607 genes are expressed in all three species. A total of 421 common enriched GO terms were identified in all three species, whereas KEGG pathway analysis revealed 13 common pathways.Conclusion and Implications: This is the first demonstration that miR‐450a is associated with cardioprotection by ischaemic conditioning in a clinically relevant porcine model and shows cardiocytoprotective effect in human cardiomyocytes, making it a promising drug candidate. The mechanism of action of miR‐450a involves multiple cardioprotective pathways.LINKED ARTICLES: This article is part of a themed issue Non‐coding RNA Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.2/issuetoc

Influenza infection may lead to serious complications in the postpartum period, therefore, oseltamivir treatment in these patients and their breastfed infants is of great importance. However, the pharmacokinetics of oseltamivir in postpartum lactating women with acute influenza infection, and the consequent infant exposure to oseltamivir are still unknown, and these data would help in assessing risk and the need for dose adjustment in breastfed infants. Six lactating women with influenza-like symptoms, at a standard dose of 75 mg oral oseltamivir twice daily for 5 days, were recruited in this phase IV clinical study during the 2011/2012 H1N1 pandemic seasons. Breast milk/colostrum and venous blood samples were taken at multiple timepoints, maternal urine samples were obtained from total output within the 12-hour observational period following the seventh dose of oseltamivir. Oseltamivir phosphate (OP) reached a maximum 69.5 +/- 29.4 ng/mL concentration in breast milk, higher than that found in the plasma, and showed elimination within similar to 8 hours. Oseltamivir carboxylate (active metabolite of OP) showed a lower, nearly steady-state concentration in breast milk during the observational period (maximum plasma concentration (C-max) = 38.4 +/- 12.9 ng/mL). Based on estimated daily milk consumption of exclusively breastfed infants, their calculated daily exposure is < 0.1% of the infant dose of oseltamivir for treatment of influenza as per marketing authorization. Here, we provide the first maternal breast milk pharmacokinetic data for oral multiple-dose oseltamivir in lactating patients with influenza and showed that its concentration in the breast milk is not sufficient to reach a therapeutic dose for breastfed infants.

Lipid-lowering drugs have been shown to have cardioprotective effects but may have hidden cardiotoxic properties. Therefore, here we aimed to investigate if chronic treatment with the novel lipid-lowering drug bempedoic acid (BA) exerts hidden cardiotoxic and/or cardioprotective effects in a rat model of acute myocardial infarction (AMI). Wistar rats were orally treated with BA or its vehicle for 28 days, anesthetized and randomized to three different groups (vehicle + ischemia/reperfusion (I/R), BA + I/R, and positive control vehicle + ischemic preconditioning (IPC)) and subjected to cardiac 30 min ischemia and 120 min reperfusion. IPC was performed by 3 × 5 min I/R cycles before ischemia. Myocardial function, area at risk, infarct size and arrhythmias were analyzed. Chronic BA pretreatment did not influence cardiac function or infarct size as compared to the vehicle group, while the positive control IPC significantly reduced the infarct size. The incidence of reperfusion-induced arrhythmias was significantly reduced by BA and IPC. This is the first demonstration that BA treatment does not show cardioprotective effect although moderately reduces the incidence of reperfusion-induced arrhythmias. Furthermore, BA does not show hidden cardiotoxic effect in rats with AMI, showing its safety in the ischemic/reperfused heart.

Hidden cardiotoxicity is defined as cardiotoxicity of a drug that manifests only in the diseased heart. We have previously shown that the proarrhythmic hidden cardiotoxic properties of a model drug, the selective cyclooxygenase-2 inhibitor rofecoxib, can be revealed in preclinical models of ischemia/reperfusion injury. As metabolic comorbidities, such as hypercholesterolemia (HC), may exacerbate hidden cardiotoxicity, we aimed to investigate the hidden cardiotoxic effects of the model drug, rofecoxib, in the presence of hypercholesterolemia. Rats were fed a high-cholesterol diet for 12 weeks and treated with 5.12 mg/kg rofecoxib. Four weeks of rofecoxib treatment surprisingly improved HC-induced mild cardiac dysfunction by restoring end-diastolic pressure, stroke work, and mechanical efficiency. Then, RNA sequencing revealed that the expression of 28 miRNAs and 300 genes was significantly altered in the HC-fed group. The HC-induced expression changes of miR-27a-5p and miR-30d-5p were reversed by rofecoxib treatment. Cdc42ep4, Cox5, and Cxcl9 genes were also counter-regulated following rofecoxib treatment compared to HC-induced changes. This is the first demonstration that rofecoxib improves HC-induced cardiac dysfunction, with the mechanism involving changes in the gene expression profile, including some key regulators of rofecoxib action.