Y-27632, a Rho-kinase inhibitor, attenuates myocardial ischemia-reperfusion injury in rats

Effect of Angiotensin 1-7 Peptide Agonist AVE 0991 on Diabetic Endothelial Dysfunction in an Experimental Animal Model: A Possible Tool to Treat Diabetic Erectile Dysfunction

Background The renin-angiotensin system and its metabolites are crucial in the pathogenesis and progression of complications of diabetes. Aim In this study, we aimed to evaluate the effect of angiotensin 1-7 non-peptide agonist AVE 0991 (576 ug/kg/day i.p.) on diabetic endothelial dysfunction. Materials and methods In this experimental animal study, we investigated the effects of angiotensin 1-7 non-peptide agonist AVE 0991 (576 ug/kg/day i.p.) treatment in male Wistar rats. Diabetes was created via injecting streptozotocin (55 mg/kg/i.p., single dose). Following the cavernous tissue submaximal phenylephrine contraction, relaxation responses were obtained by applying electrical field stimulation (0.5 ms, 40 V) for 15 seconds at 2, 4, 8, 16, 32, and 64 Hz, with two-minute intervals, respectively. To evaluate the effect of nitric oxide, the responses were compared by incubating with 100 mM N(gamma)-nitro-L-arginine methyl ester (L-NAME) for 20 minutes. Additionally, Y-27632 and sodium nitroprusside responses were evaluated in tissues contracted with submaximal doses of phenylephrine. Results Following a submaximal contraction of phenylephrine in the aorta rings, relaxation responses obtained with acetylcholine, sodium nitroprusside, and Y-27632 were impaired in diabetic rats; however, significant results were obtained with treatment. Although there was no significance between the groups in the electrical field stimulation responses, there was a significant dose-dependent difference in the treatment group in this parameter after L-NAME, sodium nitroprusside, and Y-27632 relaxation. Conclusions We determined that treatment with a non-peptide receptor antagonist of angiotensin 1-7, an enzyme detected in the aortic and cavernosum endothelium, may be a promising alternative for treating the complications of diabetes.

Pharmacologic Activation of Angiotensin-Converting Enzyme II Alleviates Diabetic Cardiomyopathy in db/db Mice by Reducing Reactive Oxidative Stress

BACKGRUOUND

Diabetes mellitus is one of the most common chronic diseases worldwide, and cardiovascular disease is the leading cause of morbidity and mortality in diabetic patients. Diabetic cardiomyopathy (DCM) is a phenomenon characterized by a deterioration in cardiac function and structure, independent of vascular complications. Among many possible causes, the renin-angiotensin-aldosterone system and angiotensin II have been proposed as major drivers of DCM development. In the current study, we aimed to investigate the effects of pharmacological activation of angiotensin-converting enzyme 2 (ACE2) on DCM.

METHODS

The ACE2 activator diminazene aceturate (DIZE) was administered intraperitoneally to male db/db mice (8 weeks old) for 8 weeks. Transthoracic echocardiography was used to assess cardiac mass and function in mice. Cardiac structure and fibrotic changes were examined using histology and immunohistochemistry. Gene and protein expression levels were examined using quantitative reverse transcription polymerase chain reaction and Western blotting, respectively. Additionally, RNA sequencing was performed to investigate the underlying mechanisms of the effects of DIZE and identify novel potential therapeutic targets for DCM.

RESULTS

Echocardiography revealed that in DCM, the administration of DIZE significantly improved cardiac function as well as reduced cardiac hypertrophy and fibrosis. Transcriptome analysis revealed that DIZE treatment suppresses oxidative stress and several pathways related to cardiac hypertrophy.

CONCLUSION

DIZE prevented the diabetes mellitus-mediated structural and functional deterioration of mouse hearts. Our findings suggest that the pharmacological activation of ACE2 could be a novel treatment strategy for DCM.

PPARβ/δ Is Required for Mesenchymal Stem Cell Cardioprotective Effects Independently of Their Anti-inflammatory Properties in Myocardial Ischemia-Reperfusion Injury

Myocardial infarction ranks first for the mortality worldwide. Because the adult heart is unable to regenerate, fibrosis develops to compensate for the loss of contractile tissue after infarction, leading to cardiac remodeling and heart failure. Adult mesenchymal stem cells (MSC) regenerative properties, as well as their safety and efficacy, have been demonstrated in preclinical models. However, in clinical trials, their beneficial effects are controversial. In an experimental model of arthritis, we have previously shown that PPARβ/δ deficiency enhanced the therapeutic effect of MSC. The aim of the present study was to compare the therapeutic effects of wild-type MSC (MSC) and MSC deficient for PPARβ/δ (KO MSC) perfused in an ex vivo mouse model of ischemia-reperfusion (IR) injury. For this purpose, hearts from C57BL/6J mice were subjected ex vivo to 30 min ischemia followed by 1-h reperfusion. MSC and KO MSC were injected into the Langendorff system during reperfusion. After 1 h of reperfusion, the TTC method was used to assess infarct size. Coronary effluents collected in basal condition (before ischemia) and after ischemia at 1 h of reperfusion were analyzed for their cytokine profiles. The dose-response curve for the cardioprotection was established ex vivo using different doses of MSC (3.10⁵, 6.10⁵, and 24.10⁵ cells/heart) and the dose of 6.10⁵ MSC was found to be the optimal concentration. We showed that the cardioprotective effect of MSC was PPARβ/δ-dependent since it was lost using KO MSC. Moreover, cytokine profiling of the coronary effluents collected in the eluates after 60 min of reperfusion revealed that MSC treatment decreases CXCL1 chemokine and interleukin-6 release compared with untreated hearts. This anti-inflammatory effect of MSC was also observed when hearts were treated with PPARβ/δ-deficient MSC. In conclusion, our study revealed that the acute cardioprotective properties of MSC in an ex vivo model of IR injury, assessed by a decreased infarct size at 1 h of reperfusion, are PPARβ/δ-dependent but not related to their anti-inflammatory effects.

From miRNA Target Gene Network to miRNA Function: miR-375 Might Regulate Apoptosis and Actin Dynamics in the Heart Muscle via Rho-GTPases-Dependent Pathways

MicroRNAs (miRNAs) are short, single-stranded, non-coding ribonucleic acid (RNA) molecules, which are involved in the regulation of main biological processes, such as apoptosis or cell proliferation and differentiation, through sequence-specific interaction with target mRNAs. In this study, we propose a workflow for predicting miRNAs function by analyzing the structure of the network of their target genes. This workflow was applied to study the functional role of miR-375 in the heart muscle (myocardium), since this miRNA was previously shown to be associated with heart diseases, and data on its function in the myocardium are mostly unclear. We identified PIK3CA, RHOA, MAPK3, PAFAH1B1, CTNNB1, MYC, PRKCA, ERBB2, and CDC42 as key genes in the miR-375 regulated network and predicted the possible function of miR-375 in the heart muscle, consisting mainly in the regulation of the Rho-GTPases-dependent signaling pathways. We implemented our algorithm for miRNA function prediction into a Python module, which is available at GitHub.

scAAV2-Mediated C3 Transferase Gene Therapy in a Rat Model with Retinal Ischemia/Reperfusion Injuries

Glaucoma is characterized by retinal ganglion cell (RGC) death and axonal loss. Therefore, neuroprotection is important in treating glaucoma. In this study, we explored whether exoenzyme C3 transferase (C3)-based gene therapy could protect retinas in an ischemia/reperfusion (I/R) injury rat model. Self-complementary adeno-associated virus 2 (scAAV2) vectors encoding either C3 protein (scAAV2-C3) or enhanced green fluorescence protein (scAAV2-EGFP) were intravitreally delivered into both eyes of rats, and I/R models (acute ocular hypertension) were made in one eye of each rat at day 7 after the injection. The rats were divided into six groups: scAAV2-C3, scAAV2-C3 with I/R, scAAV2-EGFP, scAAV2-EGFP with I/R, blank control, and blank control with I/R. TUNEL (terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick end labeling), immunohistochemistry of cleaved caspase-3, NeuN and Brn-3a, and H&E staining were used to detect apoptotic cells and other changes in the retina. The results showed that scAAV2-C3 significantly reduced the number of apoptotic RGCs and decreased cell loss in the ganglion cell layer after I/R injury, and the I/R-injured retinas treated with scAAV2-C3 were the thickest in all I/R groups. These results suggest that scAAV2-mediated C3 gene therapy is able to protect the rat retina from I/R injury and has potential in the treatment of glaucoma in the future.

Inhibition of Rho-associated protein kinase improves the survival of human induced pluripotent stem cell-derived cardiomyocytes after dissociation

Heart disease remains the leading cause of morbidity and mortality worldwide. Induced pluripotent stem cells (iPSCs) have the ability to differentiate into cardiomyocytes (CMs), rendering this cell type to be a promising pre-cursor of cardiomyocytes for cell-based cardiac regeneration. Obtaining CMs with a high yield and purity coupled with improved subsequent survival could prove to be invaluable for the future cell replacement therapeutic strategies. Rho-associated protein kinase (ROCK) is involved in a wide range of fundamental cellular functions and serves significant roles in cardiac physiology. In the present study, human (h)iPSC-CMs were generated from iPSCs by including glycogen synthase kinase 3β and Wnt inhibitors in the basal culture media. The possible effect of Y27632, a ROCK inhibitor, on hiPSC-CMs was then investigated. hiPSC-CMs of high purity were harvested with >96% of cells expressing cardiac troponin T. Additionally, treatment with 10 µM Y27632 significantly improved the viability of dissociated hiPSC-CMs. The effects of ROCK inhibitors Y27632 and fasudil, on the proliferation and apoptosis of hiPSC-CMs were also examined. Treatment with ROCK inhibitors markedly enhanced hiPSC-CM proliferation, by up to 2.5-fold, whilst Y27632 treatment reduced apoptosis in hiPSC-derived CMs under serum starvation and suspension by suppressing the expression of caspase-3. Taken together, data from the present study indicated that ROCK kinase inhibitors effectively improved the cultural system of hiPSC-derived CMs.