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This study aimed to investigate the role of apoptotic bodies (Abs) from the oxidative stressed endplate chondrocytes in regulating mineralization and potential mechanisms. Endplate chondrocytes were isolated from rats and treated with H2O2 to induce oxidative stress. The calcium deposition for matrix mineralization in the cells was examined by histological staining. The expression levels of calcification‐related genes in individual groups of cells were determined by quantitative real time‐PCR (qRT‐PCR). Subsequently, extracellular vesicles (EVs) were purified and characterized. The effect of treatment with H2O2 and/or Abs on the mineralization, extracellular PPi metabolism and related gene expression were determined. Oxidative stress significantly increased the mineralization and promoted the generation of main Abs from endplate chondrocytes. Abs were effectively endocytosed by endplate chondrocytes and co‐localized with collagen (COL)‐II in the cytoplasm, which enhanced the mineralization, alkaline phosphatase (ALP), osteocalcin (OCN), Runt‐related transcription factor 2 (RUNX2) and COL‐I expression in endplate chondrocytes. Furthermore, treatment either H2O2 or Abs significantly decreased PPi, but increased Pi production and treatment with both further enhancing the changes in endplate chondrocytes. Similarly, treatment either H2O2 or Abs significantly decreased the ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), and ankylosis protein (ANK) expression and ENPP1 promoter activity, but increased the tissue‐nonspecific alkaline phosphatase (TNAP) expression and TNAP promoter activity in endplate chondrocytes. Oxidative stress promoted the generation of Abs, which might enhance the oxidative stress‐mediated mineralization in endplate chondrocytes by regulating the PPi metabolism.

Angiotensin-(1-7) displays antihypertensive and antiproliferative properties although its effect on cardiac remodeling and hypertrophy in hypertension has not been fully elucidated. The present study was designed to examine the effect of chronic angiotensin-(1-7) treatment on myocardial remodeling, cardiac hypertrophy and underlying mechanisms in spontaneous hypertension. Adult male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats were treated with or without angiotensin-(1-7) or the angiotensin-(1-7) antagonist A-779 for 24 weeks. Mean arterial pressure, left ventricular geometry, expression of the hypertrophic markers ANP and β-MHC, collagen contents (type I and III), collagenase (MMP-1), matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of MMPs-1 (TIMP-1) were evaluated in WKY and SHR rats with or without treatment. Our data revealed that chronic angiotensin-(1-7) treatment significantly suppressed hypertension, left ventricular hypertrophy, expression of ANP and β-MHC as well as myocardial fibrosis in SHR rats, the effects of which were nullified by the angiotensin-(1-7) receptor antagonist A-779. In addition, angiotensin-(1-7) treatment significantly counteracted hypertension-induced changes in the mRNA expression of MMP-2 and TIMP-1 and collagenase activity, the effects of which were blunted by A-779. In vitro study revealed that angiotensin-(1-7) directly increased the activity of MMP-2 and MMP-9 while decreasing the content of TIMP-1 and TIMP-2. Taken together, our results revealed a protective effect of angiotensin-(1-7) against cardiac hypertrophy and collagen deposition, which may be related to concerted changes in MMPs and TIMPs levels. These data indicated the therapeutic potential of angiotensin-(1-7) in spontaneous hypertension-induced cardiac remodeling.

Background/Aims: Growth factor and oxidative stress-mediated migration and proliferation of vascular smooth muscle cells (VSMCs) play a key role in the pathogenesis of atherosclerosis. The objective of this study was to assess the ability of dehydrozingerone, a structural analog of curcumin, to inhibit PDGF-stimulated vascular functions in VSMCs. Methods: VSMCs isolated from adult rats were treated with dehydrozingerone (0 to 50 mM) before challenge with PDGF (10 ng/mL) and migration, proliferation, and collagen synthesis were assayed by transwell-migration, thymidine-, and L-proline-incorporation assays, respectively. Phosphorylation of PDGF-receptor (PDGFR) and Akt were assessed by Western blotting. Cellular protein tyrosine phosphatase (PTP) activity was determined by the extent of p-nitro-phenyl phosphate hydrolysis. Results: Dehydrozingerone elicited a concentration-dependent inhibition of PDGF-stimulated VSMC migration, proliferation, collagen synthesis, and PDGF/H2O2-stimulated phosphorylation of PDGFR-beta and downstream Akt. Dehydrozingerone also inhibited H2O2-mediated oxidation of PTP. Conclusions: Dehydrozingerone is a potent inhibitor of growth factor/ H2O2-stimulated VSMC functions and may play a critical role in regulating these events after vascular injury. Inhibition of oxidation of cellular phosphatases may represent one of the mechanisms by which dehydrozingerone inhibits these VSMC functions. Inability of the structural analog isoeugenol to inhibit PDGF-signaling suggests that the carbonyl side chain may be necessary for activity.

Objective— Vascular smooth muscle cell (VSMC) migration, proliferation, and collagen synthesis are key events involved in the pathogenesis of cardiovascular disease. Growth factors, such as platelet-derived growth factor (PDGF) and fibroblast growth factor, released during vascular injury plays a pivotal role in regulating these events. Curcumin (diferuloyl methane), a major component of the spice turmeric ( Curcuma longa ), has been shown recently to have beneficial effects in chronic conditions, such as inflammation, cancer, cystic fibrosis, and Alzheimer’s disease. The objective of this study was to investigate the ability of curcumin to inhibit PDGF-stimulated migration, proliferation, and collagen synthesis in cultured VSMCs and neointima formation after carotid artery injury in rats. Methods and Results— Curcumin (1 to 25 μM) produced a concentration-dependent inhibition of PDGF-elicited VSMC migration, proliferation, and collagen synthesis assessed by chemotaxis, [ 3 H]thymidine incorporation, and [ 3 H]- l -proline incorporation, respectively. Curcumin blocked PDGF-induced VSMC actin-cytoskeleton reorganization, attenuated PDGF signal transduction, and inhibited the binding of PDGF to its receptors. Carotid artery neointima formation was significantly attenuated by perivascular curcumin compared with vehicle controls 14 days after injury, characterized by reduced DNA synthesis, collagen synthesis, and PDGF receptor phosphorylation. Conclusions— These data suggest that curcumin is a potent inhibitor of key PDGF-stimulated VSMC functions and may play a critical role in regulating these events after vascular injury.