LCZ696 ameliorates doxorubicin-induced cardiomyocyte toxicity in rats

Doxorubicin (DOX)-based chemotherapy induces cardiotoxicity, which is considered the main bottleneck for its clinical application. In this study, we investigated the potential benefit of LCZ696, an angiotensin receptor-neprilysin inhibitor against DOX-induced cardiotoxicity in rats and H9c2 cells and determined whether the mechanism underlying any such effects involves its antioxidant activity. Male Sprague-Dawley rats were randomly separated into four groups, each consisting of 15 rats (DOX (1.5 mg/kg/day intraperitoneally for 10 days followed by non-treatment for 8 days); DOX + valsartan (31 mg/kg/day by gavage from day 1 to day 18); DOX + LCZ696 (68 mg/kg/day by gavage from day 1 to day 18); and control (saline intraperitoneally for 10 days). DOX-induced elevation of cardiac troponin T levels on day 18 was significantly reduced by LCZ696, but not valsartan. The DOX-induced increase in myocardial reactive oxygen species (ROS) levels determined using dihydroethidium was significantly ameliorated by LCZ696, but not valsartan, and was accompanied by the suppression of DOX-induced increase in p47phox. LCZ696 recovered the DOX-induced decrease in phosphorylation of adenosine monophosphate-activated protein kinase and increased the ratio of Bax and Bcl-2. In H9c2 cardiomyocytes, LCZ696 reduced DOX-induced mitochondrial ROS generation and improved cell viability more than valsartan. Our findings indicated that LCZ696 ameliorated DOX-induced cardiotoxicity in rat hearts in vivo and in vitro, possibly by mediating a decrease in oxidative stress

Versican is induced in infiltrating monocytes in myocardial infarction

Versican, a large chondroitin sulfate proteoglycan, plays a role in conditions such as wound healing and tissue remodelling. To test the hypothesis that versican expression is transiently upregulated and plays a role in the infarcted heart, we examined its expression in a rat model of myocardial infarction. Northern blot analysis demonstrated increased expression of versican mRNA. Quantitative real-time RT-PCR analysis revealed that versican mRNA began to increase as early as 6 h and reached its maximal level 2 days after coronary artery ligation. Versican mRNA then gradually decreased, while the mRNA of decorin, another small proteoglycan, increased thereafter. Versican mRNA was localized in monocytes, as indicated by CD68-positive staining, around the infarct tissue. The induction of versican mRNA was accelerated by ischemia/reperfusion (I/R), which was characterized by massive cell infiltration and enhanced inflammatory response. To examine the alteration of versican expression in monocytes/macrophages, we isolated human peripheral blood mononuclear cells and stimulated them with granulocyte/macrophage colony-stimulating factor (GM-CSF). Stimulation of mononuclear cells with GM-CSF increased the expression of versican mRNA as well as cytokine induction. The production of versican by monocytes in the infarct area represents a novel finding of the expression of an extracellular matrix gene by monocytes in the infarcted heart. We suggest that upregulation of versican in the infarcted myocardium may have a role in the inflammatory reaction, which mediates subsequent chemotaxis in the infarcted heart

Deficiency of CD44 prevents thoracic aortic dissection in a murine model

Thoracic aortic dissection (TAD) is a life-threatening vascular disease. We showed that CD44, a widely distributed cell surface adhesion molecule, has an important role in inflammation. In this study, we examined the role of CD44 in the development of TAD. TAD was induced by the continuous infusion of beta-aminopropionitrile (BAPN), a lysyl oxidase inhibitor, and angiotensin II (AngII) for 7 days in wild type (WT) mice and CD44 deficient (CD44(-/-)) mice. The incidence of TAD in CD44(-/-) mice was significantly reduced compared with WT mice (44% and 6%, p<0.01). Next, to evaluate the initial changes, aortic tissues at 24hours after BAPN/AngII infusion were examined. Neutrophil accumulation into thoracic aortic adventitia in CD44(-/-) mice was significantly decreased compared with that in WT mice (5.7 +/- 0.3% and 1.6 +/- 0.4%, p<0.01). In addition, BAPN/AngII induced interleukin-6, interleukin-1 beta, matrix metalloproteinase-2 and matrix metalloproteinase-9 in WT mice, all of which were significantly reduced in CD44(-/-) mice (all p<0.01). In vitro transmigration of neutrophils from CD44(-/-) mice through an endothelial monolayer was significantly decreased by 18% compared with WT mice (p<0.01). Our findings indicate that CD44 has a critical role in TAD development in association with neutrophil infiltration into adventitia

Host-produced ADAMTS4 Inhibits Early-Stage Tumor Growth

Several research groups demonstrated that ‘a disintegrin-like and metalloproteinase with thrombospondin type 1 motifs (ADAMTS)’-family proteases play roles in cancer progression. However, the origins and contributions of these proteases are not known. Here, we demonstrate an association between host-produced ADAMTS4 and early-stage tumor growth. Murine Lewis lung carcinoma (LLC) tumors showed marked expressions of Adamts4 and Adamts5. We examined the contributions and distributions of host-derived Adamts4 and Adamts5 on tumor growth, using Adamts4LacZ/LacZ and Adamts5LacZ/LacZ knockout mice. Interestingly, the Adamts4LacZ/LacZ mice showed enhanced tumor growth compared to wild-type mice at 5-, 10- and 12-days post-inoculation, whereas the Adamts5LacZ/LacZ mice did not show significant differences in tumor growth. We next examined LacZ distribution in LLC tumor-bearing Adamts4LacZ/LacZ mice by β-galactosidase (β-gal) staining. We found that the β-gal-positive signals were strictly localized at the interior areas of the tumor at 10 days post-inoculation. Multiple staining demonstrated that most of the β-gal-positive cells were localized at the tumor vasculature in Adamts4LacZ/LacZ mice. Interestingly, β-gal-positive signals were not co-localized with biglycan after 10 days post-inoculation, excluding the biglycan cleavage by host-derived ADAMTS4. Taken together, these findings illustrate that host-derived ADAMTS4 was expressed at the tumor vessels and was associated with early-stage tumor growth

Induction of CEMIP in Chondrocytes by Inflammatory Cytokines: Underlying Mechanisms and Potential Involvement in Osteoarthritis

In patients with osteoarthritis (OA), there is a decrease in both the concentration and molecular size of hyaluronan (HA) in the synovial fluid and cartilage. Cell migration-inducing hyaluronidase 1 (CEMIP), also known as hyaluronan (HA)-binding protein involved in HA depolymerization (HYBID), was recently reported as an HA depolymerization-related molecule expressed in the cartilage of patients with OA. However, the underlying mechanism of CEMIP regulation is not well understood. We found that CEMIP expression was transiently increased by interleukine-1 beta (IL-1 beta) stimulation in chondrocytic cells. We also observed that ERK activation and NF-kappa B nuclear translocation were involved in the induction of CEMIP by IL-1 beta. In addition, both administration of HA and mechanical strain attenuated the CEMIP induction in IL-1 beta-stimulated chondrocytes. In conclusion, we clarified the regulatory mechanism of CEMIP in chondrocytes by inflammatory cytokines and suggested the potential involvement in osteoarthritis development

Eicosapentaenoic acid prevents arterial calcification in <i>klotho</i> mutant mice

<div><p>Background</p><p>The <i>klotho</i> gene was identified as an “aging-suppressor” gene that accelerates arterial calcification when disrupted. Serum and vascular klotho levels are reduced in patients with chronic kidney disease, and the reduced levels are associated with arterial calcification. Intake of eicosapentaenoic acid (EPA), an n-3 fatty acid, reduces the risk of fatal coronary artery disease. However, the effects of EPA on arterial calcification have not been fully elucidated. The aim of this study was to determine the effect of EPA on arterial calcification in <i>klotho</i> mutant mice.</p><p>Methods and results</p><p>Four-week-old <i>klotho</i> mutant mice and wild-type (WT) mice were given a diet containing 5% EPA (EPA food, <i>klotho</i> and WT: n = 12, each) or not containing EPA (control food, <i>klotho</i> and WT: n = 12, each) for 4 weeks. Calcium volume scores of thoracic and abdominal aortas assessed by computed tomography were significantly elevated in <i>klotho</i> mice after 4 weeks of control food, but they were not elevated in <i>klotho</i> mice after EPA food or in WT mice. Serum levels of EPA and resolvin E1, an active metabolite of EPA, in EPA food-fed mice were significantly increased compared to those in control food-fed mice. An oxidative stress PCR array followed by quantitative PCR revealed that NADPH oxidase-4 (<i>NOX4</i>), an enzyme that generates superoxide, gene expression was up-regulated in arterial smooth muscle cells (SMCs) of <i>klotho</i> mice. Activity of NOX was also significantly higher in SMCs of <i>klotho</i> mice than in those of WT mice. EPA decreased expression levels of the NOX4 gene and NOX activity. GPR120, a receptor of n-3 fatty acids, gene knockdown by siRNA canceled effects of EPA on NOX4 gene expression and NOX activity in arterial SMCs of <i>klotho</i> mice.</p><p>Conclusions</p><p>EPA prevents arterial calcification together with reduction of NOX gene expression and activity via GPR120 in <i>klotho</i> mutant mice.</p></div

Gene expression of cytoglobin (<i>Cygb</i>), glutathione peroxidase 3 (<i>GPX3</i>) and NADPH oxidase (<i>NOX</i>) and activity of NOX.

<p>A to C, Expression levels of <i>Cygb</i> (A), <i>GPX3</i> (B) and <i>NOX4</i> (C) genes in arterial smooth muscle cells (SMCs) of wild-type (WT) and <i>klotho</i> mutant (<i>kl/kl)</i> mice treated with EPA and not treated with EPA (control) (n = 6, each). D, NOX activity in arterial SMCs of WT and <i>kl/kl</i> mice treated with EPA and not treated with EPA (control) (n = 6, each).</p