Kappa-Opioid Agonist U50,488H-Mediated Protection Against Heart Failure Following Myocardial Ischemia/Reperfusion: Dual Roles of Heme Oxygenase-1

Background/Aims: Myocardial ischemia/reperfusion (I/R) injury remains a great challenge in clinical therapy. Tissue inhibitor of metalloproteinases 3 (TIMP3) plays a crucial role in heart physiological and pathophysiological processes. However, the effects of TIMP3 on I/R injury remain unknown. Methods: C57BL/6 mice were infected with TIMP3 adenovirus by local delivery in myocardium followed by I/R operation or doxorubicin treatment. Neonatal rat cardiomyocytes were pretreated with TIMP3 adenovirus prior to anoxia/reoxygenation (A/R) treatment in vitro. Histology, echocardiography, in vivo phenotypical analysis, flow cytometry and western blotting were used to investigate the altered cardiac function and underlying mechanisms. Results: The results showed that upregulation of TIMP3 in myocardium markedly inhibited myocardial infarct areas and the cardiac dysfunction induced by I/R or by doxorubicin treatment. TUNEL staining revealed that TIMP3 overexpression attenuated I/R-induced myocardial apoptosis, accompanied by decreased Bax/Bcl-2 ratio, Cleaved Caspase-3 and Cleaved Caspase-9 expression. In vitro, A/R-induced cardiomyocyte apoptosis was abrogated by pharmacological inhibition of reactive oxygen species (ROS) production or MAPKs signaling. Attenuation of ROS production reversed A/R-induced MAPKs activation, whereas MAPKs inhibitors showed on effect on ROS production. Furthermore, in vivo or in vitro overexpression of TIMP3 significantly inhibited I/R- or A/R-induced ROS production and MAPKs activation. Conclusion: Our findings demonstrate that TIMP3 upregulation protects against cardiac I/R injury through inhibiting myocardial apoptosis. The mechanism may be related to inhibition of ROS-initiated MAPKs pathway. This study suggests that TIMP3 may be a potential therapeutic target for the treatment of I/R injury.

Section: Methodsmentioning

confidence: 99%

“…Myocardium infarct size was measured as previously described [19, 20]. After anesthesia, the heart was excised, and 1 mL of 5% Evans Blue dye was injected into the ascending aorta to visualize the nonischemic area.…”

Section: Methodsmentioning

confidence: 99%

Overexpression of TIMP3 Protects Against Cardiac Ischemia/Reperfusion Injury by Inhibiting Myocardial Apoptosis Through ROS/Mapks Pathway

Liu¹,

Jing

Dong³

et al. 2017

“…Cardiac function was examined by echocardiography [11]. Echocardiography was performed in rats anesthetized with isoflurane at 2 weeks (before RDN) and repeated at 6 weeks after MI.…”

Section: Echocardiographymentioning

confidence: 99%

Renal Denervation Effects on Myocardial Fibrosis and Ventricular Arrhythmias in Rats with Ischemic Cardiomyopathy

Zhang

Chu

et al. 2018

Background/Aims: To investigate the impact of renal denervation (RDN) on myocardial fibrosis and ventricular arrhythmias (VAs) in rats with ischemic cardiomyopathy. Methods: An ischemic cardiomyopathy model was reproduced with myocardial infarction (MI) in adult Sprague-Dawley male rats. The RDN/Sham-RDN procedure was performed at 2 weeks after MI. Sham-MI and sham-RDN rats served as the control group. At 4 weeks after RDN, programmed electrical stimulation (PES) was used to induce VAs, including ventricular tachycardia and ventricular fibrillation, in all 3 groups (MI+RDN, MI, and control groups). At the end of PES, heart and kidney samples were harvested. Immunofluorescence labeling was used to investigate the distribution of connexin 43 (Cx43) in the infarcted border zone. Masson's trichrome stain was adopted to determine the degree of cardiac fibrosis. Western blotting was performed to identify the expression of transforming growth factor beta 1 (TGF-β1), α-smooth muscle actin (α-SMA), and Cx43. An enzyme-linked immunosorbent assay (ELISA) was used to detect the serum levels of B-type natriuretic peptide (BNP) and the amino-terminal propeptides of type I and III collagen (PINP and PIIINP, respectively) and the expression level of renal norepinephrine. Results: Compared with the MI group, RDN significantly decreased the inducibility of VAs (MI+RDN 3/8 rats vs. MI 8/9 rats, P < 0.05; control 1/8 rats) with PES, reduced myocardial fibrosis estimated by collagen volume fraction (MI+RDN 31.10 ± 3.97% vs. MI 54.80 ± 16.39%, P < 0.001; control 4.41 ± 0.92% ), suppressed TGF-β1 (P < 0.01) and α-SMA (P < 0.001) levels, and attenuated both PINP (MI+RDN 41.44 ± 10.10 ng/mL vs. MI 95.49 ± 24.83 ng/mL, P < 0.001; control 11.90 ± 4.96 ng/mL) and PIIINP (MI+RDN 82.12 ± 30.79 ng/mL vs. MI 124.60 ± 26.64 ng/mL, P < 0.05; control 64.69 ± 23.84 ng/mL) levels. Moreover, RDN reversed the abnormal myocardial distribution of Cx43 and its reduction by MI damage (P < 0.01). Conclusions: RDN reduced myocardial fibrosis and suppressed VAs in a rat model of ischemic cardiomyopathy.

“…κ-opioid receptors are a class of opioid receptors first reported by Martin which have been detected in the vascular system [16,17]. κ-opioid receptors have been identified in pulmonary arteries and their expression levels increase during hypoxia [18].…”

Section: Introductionmentioning

confidence: 99%

The Protective Effects of Κ-Opioid Receptor Stimulation in Hypoxic Pulmonary Hypertension Involve Inhibition of Autophagy Through the AMPK-MTOR Pathway

Zhou

Wang

et al. 2017

Self Cite

Background/Aims: In a previous study, we showed that κ-opioid receptor stimulation with the selective agonist U50,488H ameliorated hypoxic pulmonary hypertension (HPH). However, the roles that pulmonary arterial smooth muscle cell (PASMC) proliferation, apoptosis, and autophagy play in κ-opioid receptor-mediated protection against HPH are still unknown. The goal of the present study was to investigate the role of autophagy in U50,488H-induced HPH protection and the underlying mechanisms. Methods: Rats were exposed to 10% oxygen for three weeks to induce HPH. After hypoxia, the mean pulmonary arterial pressure (mPAP) and the right ventricular pressure (RVP) were measured. Cell viability was monitored using the Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis was detected by flow cytometry and Western blot. Autophagy was assessed by means of the mRFP-GFP-LC3 adenovirus transfection assay and by Western blot. Results: Inhibition of autophagy by the administration of chloroquine prevented the development of HPH in the rat model, as evidenced by significantly reduced mPAP and RVP, as well as decreased autophagy. U50,488H mimicked the effects of chloroquine, and the effects of U50,488H were blocked by nor-BNI, a selective κ-opioid receptor antagonist. In vitro experiments showed that the inhibition of autophagy by chloroquine was associated with decreased proliferation and increased apoptosis of PASMCs. Under hypoxia, U50,488H also significantly inhibited autophagy, reduced proliferation and increased apoptosis of PASMCs. These effects of U50,488H were blocked by nor-BNI. Moreover, exposure to hypoxic conditions significantly increased AMPK phosphorylation and reduced mTOR phosphorylation, and these effects were abrogated by U50,488H. The effects of U50,488H on PASMC autophagy were inhibited by AICAR, a selective AMPK agonist, or by rapamycin, a selective mTOR inhibitor. Conclusion: Our data provide evidence for the first time that κ-opioid receptor stimulation protects against HPH by inhibiting PASMCs autophagy via the AMPK-mTOR pathway.