Peptidase Inhibitor 16 Attenuates Left Ventricular Injury and Remodeling After Myocardial Infarction by Inhibiting the HDAC1-Wnt3a-ß-Catenin Signaling Axis.

Background Myocardial infarction (MI) is a cardiovascular disease with high morbidity and mortality. PI16 (peptidase inhibitor 16), as a secreted protein, is highly expressed in heart diseases such as heart failure. However, the functional role of PI16 in MI is unknown. This study aimed to investigate the role of PI16 after MI and its underlying mechanisms. Methods and Results PI16 levels after MI were measured by enzyme-linked immunosorbent assay and immunofluorescence staining, which showed that PI16 was upregulated in the plasma of patients with acute MI and in the infarct zone of murine hearts. PI16 gain- and loss-of-function experiments were used to investigate the potential role of PI16 after MI. In vitro, PI16 overexpression inhibited oxygen-glucose deprivation-induced apoptosis in neonatal rat cardiomyocytes, whereas knockdown of PI16 exacerbated neonatal rat cardiomyocyte apoptosis. In vivo, left anterior descending coronary artery ligation was performed on PI16 transgenic mice, PI16 knockout mice, and their littermates. PI16 transgenic mice showed decreased cardiomyocyte apoptosis at 24 hours after MI and improved left ventricular remodeling at 28 days after MI. Conversely, PI16 knockout mice showed aggravated infract size and remodeling. Mechanistically, PI16 downregulated Wnt3a (wingless-type MMTV integration site family, member 3a)/ß-catenin pathways, and the antiapoptotic role of PI16 was reversed by recombinant Wnt3a in oxygen-glucose deprivation-induced neonatal rat cardiomyocytes. PI16 also inhibited HDAC1 (class I histone deacetylase) expression, and overexpression HDAC1 abolished the inhibition of apoptosis and Wnt signaling of PI16. Conclusions In summary, PI16 protects against cardiomyocyte apoptosis and left ventricular remodeling after MI through the HDAC1-Wnt3a-ß-catenin axis.

ROS inhibition increases KDM6A-mediated NOX2 transcription and promotes macrophages oxidative stress and M1 polarization.

Reactive oxygen species (ROS) play an essential role in macrophage polarization. However, the adverse effects of ROS reduction by influencing epigenetics are often ignored. In this study, lipopolysaccharide (LPS) was used to stimulate macrophages to increase the ROS in cells, and N-acetylcysteine (NAC) was used to reduce ROS. Inflammatory factors such as interleukin 1ß (IL-1ß), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) were used to evaluate the M1 polarization level of macrophages. Chip was used to detect the tri-methylation at lysine 27 of histone H3 (H3K27me3) level at the promoter site. It was found that the decrease of ROS in macrophages would also cause the increase of the H3K27me3 demethylase KDM6A and lead to the reduction of H3K27me3 in the NOX2 promoter, which would increase the transcription level of NOX2 and the production of ROS and ultimately promote the production of inflammatory factors. Knockout of KDM6A can reduce the transcription of NOX2 and the production of ROS of macrophages, thus preventing the M1 polarization of macrophages. The elimination of ROS in macrophages will affect macrophages by increasing KDM6A and making them produce more ROS, thus inducing oxidative stress. In comparison, direct inhibition of KDM6A can reduce ROS production and inhibit macrophage M1 polarization more effectively.

Interleukin 10 Attenuates Angiotensin II-Induced Aortic Remodelling by Inhibiting Oxidative Stress-Induced Activation of the Vascular p38 and NF-κB Pathways.

Interleukin 10 (IL-10) is a probable anti-inflammatory factor that can attenuate hypertrophic remodelling caused by overloaded pressure and improve cardiac function. In this study, IL-10 was decreased in both the plasma of hypertensive patients and the aortic vessels of angiotensin II (Ang II)-induced hypertensive mice. IL-10 was unable to alter blood pressure in the case of Ang II-induced hypertension. The aortic thickness, collagen deposition, and the levels of fibrosis-associated markers, including collagen type I α 1 (Col1α1), connective tissue growth factor (CTGF), transforming growth factor-ß (TGF-ß), and matrix metalloproteinase 2 (MMP2), were significantly reduced in the IL-10 treatment group compared with the vehicle group after Ang II treatment. Moreover, IL-10 treatment significantly inhibited the number of CD45+ positive cells and the mRNA expression levels of proinflammatory cytokines in the vascular tissue of Ang II-infused mice. Furthermore, dihydroethidium (DHE) and 4hydroxynonenal (4-HNE) staining showed that IL-10 decreased Ang II-induced vascular oxidative stress and lipid peroxidation. Furthermore, IL-10 suppressed Ang II-induced proliferation, fibrosis, and inflammation of mouse vascular adventitial fibroblasts (mVAFs). Mechanistically, IL-10 suppressed the phosphorylation of p38 mitogen-activated protein (MAP) kinase and nuclear factor-κB (NF-κB) in Ang II-induced vascular fibrosis. In summary, our data indicated that IL-10, as a potential therapeutic target treatment, could limit the progression of Ang II-induced aortic remodelling.

Non-Invasive Local Acoustic Therapy Ameliorates Diabetic Heart Fibrosis by Suppressing ACE-Mediated Oxidative Stress and Inflammation in Cardiac Fibroblasts.

PURPOSE: The extent of myocardial fibrosis is closely related to the prognosis of diabetic cardiomyopathy (DCM). Low-intensity pulsed ultrasound (LIPUS) has been reported to have multiple biological effects. However, the effect of LIPUS on diabetic heart fibrosis remains unclear. The present study aimed to investigate the effect of LIPUS on diabetic heart fibrosis and explore its underlying mechanisms. METHODS AND RESULTS: High glucose (HG) was applied to cultured neonatal rat cardiac fibroblasts (NRCFs) to mimic the in vivo hyperglycemia microenvironment. LIPUS (19.30 mW/cm2 to 77.20 mW/cm2) dose-dependently inhibited HG-induced fibrotic response in NRCFs. Also, LIPUS downregulated NADPH oxidase 4 (NOX4)-associated oxidative stress and nod-like receptor protein-3 (NLRP3) inflammasome activation in NRCFs. In vivo, diabetes in mice was induced with streptozotocin (STZ). Mice in the LIPUS group and STZ + LIPUS group were treated with LIPUS (77.20 mW/cm2) twice a week for 12 weeks and then euthanized at 12 weeks or 24 weeks post-diabetes. Treatment with LIPUS significantly ameliorated the progression of cardiac fibrosis (Masson staining 6.5 ± 2.3% vs. 2.8 ± 1.5%, P < 0.001) and dysfunction (E/A ratio 1.35 ± 0.14 vs. 1.59 ± 0.11, P < 0.05), as well as NOX4-associated oxidative stress (relative expression fold of NOX4 1.43 ± 0.12 vs. 1.07 ± 0.10, P < 0.01; relative DHE fluorescence 1.51 ± 0.13 vs. 1.28 ± 0.06, P < 0.05) and NLRP3 inflammasome activation (relative expression fold of NLRP3 1.57 ± 0.12 vs. 1.05 ± 0.16, P < 0.01), at 12 weeks post-diabetes. At 24 weeks post-diabetes, the heart function in diabetic mice treated with LIPUS was still significantly better than untreated diabetic mice (E/A ratio 1.08 ± 0.12 vs. 1.49 ± 0.14, P < 0.001). Further exploration revealed that LIPUS significantly attenuated the upregulated angiotensin-converting enzyme (ACE) and angiotensin II (AngII), in both HG-induced NRCFs and diabetic hearts (relative expression of ACE in myocardium 3.77 ± 0.55 vs. 1.07 ± 0.13, P < 0.001; AngII in myocardium 115.5 ± 21.77 ng/ml vs. 84.28 ± 9.03 ng/ml, P < 0.01). Captopril, an ACE inhibitor, inhibited NOX4-associated oxidative stress and NLRP3 inflammasome activation in both HG-induced NRCFs and diabetic hearts. CONCLUSION: Our results indicate that non-invasive local LIPUS therapy attenuated heart fibrosis and dysfunction in diabetic mice and the effect could be largely preserved at least 12 weeks after suspending LIPUS stimulation. LIPUS ameliorated diabetic heart fibrosis by inhibiting ACE-mediated NOX4-associated oxidative stress and NLRP3 inflammasome activation in cardiac fibroblasts. Our study may provide a novel therapeutic approach to hamper the progression of diabetic heart fibrosis.