K-80003 Inhibition of Macrophage Apoptosis and Necrotic Core Development in Atherosclerotic Vulnerable Plaques.

PURPOSE: Macrophage apoptosis coupled with a defective phagocytic clearance of the apoptotic cells promotes plaque necrosis in advanced atherosclerosis, which causes acute atherothrombotic vascular disease. Nonsteroidal anti-inflammatory drug sulindac derivative K-80003 treatment was previously reported to dramatically attenuate atherosclerotic plaque progression and destabilization. However, the underlying mechanisms are not fully understood. This study aimed to determine the role of K-80003 on macrophage apoptosis and elucidate the underlying mechanism. METHODS: The mouse model of vulnerable carotid plaque in ApoE-/- mice was developed in vivo. Consequently, mice were randomly grouped into two study groups: the control group and the K-80003 group (30 mg/kg/day). Samples of carotid arteries were collected to determine atherosclerotic necrotic core area, cellular apoptosis, and oxidative stress. The effects of K-80003 on RAW264.7 macrophage apoptosis, oxidative stress, and autophagic flux were also examined in vitro. RESULTS: K-80003 significantly suppressed necrotic core formation and inhibited cellular apoptosis of vulnerable plaques. K-80003 can also inhibit 7-ketocholesterol-induced macrophage apoptosis in vitro. Furthermore, K-80003 inhibited intraplaque cellular apoptosis mainly through the suppression of oxidative stress, which is a key cause of advanced lesional macrophage apoptosis. Mechanistically, K-80003 prevented 7-ketocholesterol-induced impairment of autophagic flux in macrophages, evidenced by the decreased LC3II and SQSTM1/p62 expression, GFP-RFP-LC3 cancellation upon K-80003 treatment. CONCLUSION: Inhibition of macrophage apoptosis and necrotic core formation by autophagy-mediated reduction of oxidative stress is one mechanism of the suppression of plaque progression and destabilization by K-80003.

Prostaglandin E1 attenuates AngII-induced cardiac hypertrophy via EP3 receptor activation and Netrin-1upregulation.

AIMS: Pathological cardiac hypertrophy induced by activation of the renin-angiotensin-aldosterone system (RAAS) is one of the leading causes of heart failure. However, in current clinical practice, the strategy for targeting the RAAS is not sufficient to reverse hypertrophy. Here, we investigated the effect of prostaglandin E1 (PGE1) on angiotensin II (AngII)-induced cardiac hypertrophy and potential molecular mechanisms underlying the effect. METHODS AND RESULTS: Adult male C57 mice were continuously infused with AngII or saline and treated daily with PGE1 or vehicle for two weeks. Neonatal rat cardiomyocytes were cultured to detect AngII-induced hypertrophic responses. We found that PGE1 ameliorated AngII-induced cardiac hypertrophy both in vivo and in vitro. The RNA sequencing (RNA-seq) and expression pattern analysis results suggest that Netrin-1 (Ntn1) is the specific target gene of PGE1. The protective effect of PGE1 was eliminated after knockdown of Ntn1. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the PGE1-mediated signaling pathway changes are associated with the mitogen-activated protein kinase (MAPK) pathway. PGE1 suppressed AngII-induced activation of the MAPK signaling pathway, and such an effect was attenuated by Ntn1 knockdown. Blockade of MAPK signaling rescued the phenotype of cardiomyocytes caused by Ntn1 knockdown, indicating that MAPK signaling may act as the downstream effector of Ntn1. Furthermore, inhibition of the E-prostanoid (EP) 3 receptor, as opposed to the EP1, EP2, or EP4 receptor, in cardiomyocytes reversed the effect of PGE1, and activation of EP3 by sulprostone, a specific agonist, mimicked the effect of PGE1. CONCLUSION: In conclusion, PGE1 ameliorates AngII-induced cardiac hypertrophy through activation of the EP3 receptor and upregulation of Ntn1, which inhibits the downstream MAPK signaling pathway. Thus, targeting EP3, as well as the Ntn1-MAPK axis, may represent a novel approach for treating pathological cardiac hypertrophy.

Low-level overexpression of p53 promotes warfarin-induced calcification of porcine aortic valve interstitial cells by activating Slug gene transcription.

The most frequently used oral anti-coagulant warfarin has been implicated in inducing calcification of aortic valve interstitial cells (AVICs), whereas the mechanism is not fully understood. The low-level activation of p53 is found to be involved in osteogenic transdifferentiation and calcification of AVICs. Whether p53 participates in warfarin-induced AVIC calcification remains unknown. In this study, we investigated the role of low-level p53 overexpression in warfarin-induced porcine AVIC (pAVIC) calcification. Immunostaining, quantitative PCR, and Western blotting revealed that p53 was expressed in human and pAVICs and that p53 expression was slightly increased in calcific human aortic valves compared with non-calcific valves. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling staining indicated that apoptosis slightly increased in calcific aortic valves than in non-calcific valves. Warfarin treatment led to a low-level increase of p53 mRNA and protein in both pAVICs and mouse aortic valves. Low-level overexpression of p53 in pAVICs via an adenovirus vector did not affect pAVIC apoptosis but promoted warfarin-induced calcium deposition and expression of osteogenic markers. shRNA-mediated p53 knockdown attenuated the pAVIC calcium deposition and osteogenic marker expression. Moreover, ChIP and luciferase assays showed that p53 was recruited to the slug promoter and activated slug expression in calcific pAVICs. Of note, overexpression of Slug increased osteogenic marker Runx2 expression, but not pAVIC calcium deposition, and Slug knockdown attenuated pAVIC calcification and p53-mediated pAVIC calcium deposition and expression of osteogenic markers. In conclusion, we found that p53 plays an important role in warfarin induced pAVIC calcification, and increased slug transcription by p53 is required for p53-mediated pAVIC calcification.

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.

Nur77 Deficiency Exacerbates Macrophage NLRP3 Inflammasome-Mediated Inflammation and Accelerates Atherosclerosis.

Purpose: Activation of NLR (nucleotide-binding and leucine-rich repeat immune receptor) family pyrin domain containing 3 (NLRP3) inflammasome mediating interleukin- (IL-) 1ß secretion has emerged as an important component of inflammatory processes in atherogenesis. The nuclear receptor Nur77 is highly expressed in human atherosclerotic lesions; however, its functional role in macrophage NLRP3 inflammasome activation has not yet been clarified. Methods, Materials, and Results. Eight-week-old apolipoprotein E (ApoE)-/- and ApoE-/- Nur77-/- mice that were fed a Western diet underwent partial ligation of the left common carotid artery (LCCA) and left renal artery (LRA) to induce atherogenesis. Four weeks later, severe plaque burden associated with increased lipid deposition, reduced smooth muscle cells, macrophage infiltration, and decreased collagen expression was identified in ApoE-/- Nur77-/- mice compared with those in ApoE-/- mice. ApoE-/- Nur77-/- mice showed increased macrophage inflammatory responses in carotid atherosclerotic lesions. In vitro studies demonstrated that oxidized low-density lipoprotein cholesterol (ox-LDL) increased the release of lactate dehydrogenase (LDH) and upregulated the expressions of cleaved caspase-1, cleaved IL-1ß and gasdermin D (GSMD) in WT peritoneal macrophages (PMs) in a NLRP3-dependent manner. Nur77-/- PMs exhibited a further increased level of NLRP3 inflammasome-mediated inflammation under ox-LDL treatment compared with WT PMs. Mechanistically, Nur77 could bind to the promoter of NLRP3 and inhibit its transcriptional activity. Conclusions: This study demonstrated that Nur77 deletion promotes atherogenesis by exacerbating NLRP3 inflammasome-mediated inflammation.

Angiotensin II Promotes White Adipose Tissue Browning and Lipolysis in Mice.

Emerging evidence has revealed that all components of the renin-angiotensin system (RAS) are present in adipose tissue. Angiotensin II (Ang II), the major bioactive component of the RAS, has been recognized as an adipokine involved in regulating energy homeostasis. However, the precise role of Ang II in white adipose tissue (WAT) remodeling remains to be elucidated. In this present study, C57BL/C male mice were continuously infused with different doses of Ang II (1.44 mg/kg/d or 2.5 mg/kg/d) or saline for 2 weeks and treated with or without the Ang II type 1 receptor blocker valsartan. H&E staining and immunohistochemistry were conducted to investigate the white-to-brown fat conversion. The level of serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) was measured. RNA sequencing was employed to explore the differentially expressed genes and their enriched pathways between control and Ang II groups. Our results showed that Ang II substantially resulted in loss of body weight and fat mass. Most importantly, Ang II treatment induced WAT browning in mice, which was partially attenuated by valsartan treatment. Furthermore, Ang II perturbed the serum lipid profiles. Ang II treatment elevated serum levels of TC, TG, LDL-C, and HDL-C in mice. Mechanistically, thermogenesis, cell respiration, and lipid metabolism-associated mRNAs showed significantly increased expression profiling in Ang II-treated WATs compared with control WATs. Moreover, we found that Ang II treatment enhanced AMPK phosphorylation in adipocytes. Therefore, Ang II promotes WAT browning and lipolysis via activating the AMPK signaling pathway.

A Novel Anticancer Therapeutic Strategy to Target Autophagy Accelerates Radiation-Associated Atherosclerosis.

PURPOSE: Autophagy inhibition is a novel therapeutic strategy suggested for patients with advanced cancer, especially those who have undergone radiation therapy. In the present study, we investigated whether autophagy inhibitors accelerate the progression of radiation-associated atherosclerosis (RAA). METHODS AND MATERIALS: Eight-week-old apolipoprotein (ApoE-/-) mice were fed a Western diet, and their left common carotid arteries were partially ligated to induce atherogenesis. Four weeks later, local ionizing radiation (IR) at a dose of 5 or 10 Gy was used to induce RAA in the left common carotid artery. After another 4 weeks, severe plaque burden associated with increased macrophage infiltration and lipid deposition, reduced smooth muscle cells, and decreased collagen expression was observed. In addition, these changes occurred in a dose-dependent manner. Improved autophagic flux caused by IR was observed in both macrophages of the atherosclerotic plaque and peritoneal macrophages in vitro. The inhibition of autophagic flux by chloroquine (50 mg/kg/d) further accelerated the progression of RAA in the left common carotid arteries of ApoE-/- mice. Furthermore, chloroquine treatment exacerbated IR-induced p65 nuclear translocation, IκBα degradation, and transcription of nuclear factor-κB (NF-κB) target genes in peritoneal macrophages. CONCLUSIONS: IR promotes atherogenesis and increases autophagic flux. In addition, autophagy inhibition by chloroquine accelerates the progression of RAA lesions by stimulating NF-κB-mediated inflammatory responses in macrophages.

MicroRNA-327 regulates cardiac hypertrophy and fibrosis induced by pressure overload.

MicroRNA (miRNA/miR) dysregulation has been reported to be fundamental in the development and progression of cardiac hypertrophy and fibrosis. In the present study, miR-327 levels in fibroblasts were increased in response to cardiac hypertrophy induced by transverse aortic constriction with prominent cardiac fibrosis, particularly when compared with the levels in unstressed cardiomyocytes. In neonatal rat cardiac fibroblasts, induced expression of miR-327 upregulated fibrosis-associated gene expression and activated angiotensin II-induced differentiation into myofibroblasts, as assessed via α-smooth muscle actin staining. By contrast, miR-327 knockdown mitigated angiotensin II-induced differentiation. Cardiac fibroblast proliferation was not affected under either condition. In a mouse model subjected to transverse aortic constriction, miR-327 knockdown through tail-vein injection reduced the development of cardiac fibrosis and ventricular dysfunction. miR-327 was demonstrated to target integrin ß3 and diminish the activation of cardiac fibroblasts. Thus, the present study supports the use of miR-327 as a therapeutic target in the reduction of cardiac fibrosis.