Oxidant Generation Predominates Around Calcifying Foci and Enhances Progression of Aortic Valve Calcification

Liberman, Marcel; Bassi, Estêvão; Martinatti, Marina K; Lario, Fábio Cerqueira; Wosniak, João; Pomerantzeff, Pablo Maria Alberto; Laurindo, Francisco Rafael Martins

doi:10.1161/atvbaha.107.156745

Cited by 182 publications

(166 citation statements)

References 41 publications

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“…A recent study demonstrated that increased ROS generation, particularly H 2 O 2 , is predominately located around calcifying foci, which potentiates aortic valve calcification progression (54). By contrast, H 2 O 2 has been shown to have adverse effects on osteogenic differentiation of MC3T3-E1 cells, a pre-osteoblastic cell line (53), and primary bone marrow stromal cells and calvarial osteoblast precursors (55).…”

Section: Discussionmentioning

confidence: 99%

Oxidative Stress Induces Vascular Calcification through Modulation of the Osteogenic Transcription Factor Runx2 by AKT Signaling

Byon

Javed

Dai

et al. 2008

Journal of Biological Chemistry

530

514

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Oxidative stress plays a critical role in the pathogenesis of atherosclerosis including the formation of lipid laden macrophages and the development of inflammation. However, oxidative stress-induced molecular signaling that regulates the development of vascular calcification has not been investigated in depth. Osteogenic differentiation of vascular smooth muscle cells (VSMC) is critical in the development of calcification in atherosclerotic lesions. An important contributor to oxidative stress in atherosclerotic lesions is the formation of hydrogen peroxide from diverse sources in vascular cells. In this study we defined molecular signaling that is operative in the H 2 O 2 -induced VSMC calcification. We found that H 2 O 2 promotes a phenotypic switch of VSMC from contractile to osteogenic phenotype. This response was associated with an increased expression and transactivity of Runx2, a key transcription factor for osteogenic differentiation. The essential role of Runx2 in oxidative stress-induced VSMC calcification was further confirmed by Runx2 depletion and overexpression. Inhibition of Runx2 using short hairpin RNA blocked VSMC calcification, and adenovirus-mediated overexpression of Runx2 alone induced VSMC calcification. Inhibition of H 2 O 2 -activated AKT signaling blocked VSMC calcification and Runx2 induction concurrently. This blockage did not cause VSMC apoptosis. Taken together, our data demonstrate a critical role for AKT-mediated induction of Runx2 in oxidative stress-induced VSMC calcification.Atherosclerosis is characterized by the presence of atherosclerotic lesions in the arterial intima that leads to narrowing of the vessel lumen. Vascular calcification, the presence of calcium deposits in the vessel wall, is a feature of advanced atherosclerosis and reduces elasticity and compliance of the vessel wall (1). Hence, the extent of calcification is a key risk factor in the pathogenesis of the disease. Several cell types, such as endothelium, monocytes, and vascular smooth muscle cells (VSMC), 5 are involved in different stages of lesion development. VSMC contribute to the development of atherosclerotic lesions through increased migration, proliferation, secretion of matrix components, osteogenic differentiation, and the associated calcification (1). During this process, the differentiated VSMC undergo de-differentiation, and subsequently osteogenic transition that results in vascular calcification (2).Many factors that have been linked to an increased prevalence of vascular calcification are associated with elevated oxidative stress, including hypercholesterolemia, hypertension, diabetes mellitus, and dialysis-dependent end stage renal disease (3-6). Pro-oxidant events in atherosclerosis include the production of reactive oxygen species (ROS) and nitrogen species by vascular cells (7). Of particular interest is hydrogen peroxide (H 2 O 2 ), which is a cell-permeable ROS that has emerged as a key mediator of intracellular signaling (8 -10). H 2 O 2 is produced in vascular cells by multiple enzyma...

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Section: Discussionmentioning

confidence: 99%

Oxidative Stress Induces Vascular Calcification through Modulation of the Osteogenic Transcription Factor Runx2 by AKT Signaling

Byon

Javed

Dai

et al. 2008

Journal of Biological Chemistry

530

514

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“…Low concentrations of H 2 O 2 increase ALP activity and potentiate the progression of aortic valve calcification [22,23] . The levels of expression of mRNAs for OPN and OCN were significantly greater in ROS-treated human dental pulp cells [24] .…”

Section: Discussionmentioning

confidence: 99%

Oxidized low-density lipoprotein and β-glycerophosphate synergistically induce endothelial progenitor cell ossification

Liu

Chen

et al. 2011

Acta Pharmacol Sin

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Aim: To investigate the ability of ox-LDL to induce ossification of endothelial progenitor cells (EPCs) in vitro and explored whether oxidative stress, especially hypoxia inducible factor-1α (HIF-1α) and reactive oxygen species (ROS), participate in the ossific process. Methods: Rat bone marrow-derived endothelial progenitor cells (BMEPCs) were cultured in endothelial growth medium supplemented with VEGF (40 ng/mL) and bFGF (10 ng/mL). The cells were treated with oxidized low-density lipoprotein (ox-LDL, 5 µg/mL) and/or β-glycerophosphate (β-GP, 10 mmol/L). Calcium content and Von Kossa staining were used as the measures of calcium deposition. Ossific gene expression was determined using RT-PCR. The expression of osteocalcin (OCN) was detected with immunofluorescence. Alkaline phosphatase (ALP) activity was analyzed using colorimetric assay. Intercellular reactive oxygen species (ROS) were measured with flow cytometry. Results: BMEPCs exhibited a spindle-like shape. The percentage of cells that expressed the cell markers of EPCs CD34, CD133, and kinase insert domain-containing receptor (KDR) were 46.2%±5.8%, 23.5%±4.0%, and 74.3%±8.8%, respectively. Among the total cells, 78.3%±4.2% were stained with endothelial-specific fluorescence. Treatment of BMEPCs with ox-LDL significantly promoted calcium deposition, which was further significantly enhanced by co-treatment with β-GP. The same treatments significantly increased the gene expression of core-binding factor a-1 (cbfa-1) and OCN, while decreased the gene expression of osteoprotegerin (OPG). The treatments also significantly enhanced the activity of ALP, but did not affect the number of OCN + cells. Furthermore, the treatments significantly increased ROS and activated the hypoxia inducible factor-1α (HIF-1α). In all these effects, ox-LDL acted synergistically with β-GP. Conclusion: Ox-LDL and β-GP synergistically induce ossification of BMEPCs, in which an oxidizing mechanism is involved.

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“…Various clinical, 1 histological, 2 and animal 3 studies support the coincidence of osteoporosis and vascular calcification and suggest that processes in vascular calcification are similar to those of bone remodeling. 4 Hence, a better molecular understanding of common processes of these comorbidities may lead to more efficient therapeutic strategies against these age-related diseases.…”

mentioning

confidence: 97%

miR-125b Regulates Calcification of Vascular Smooth Muscle Cells

Goettsch

Rauner

Pacyna

et al. 2011

The American Journal of Pathology

167

124

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Vascular calcification is a prominent feature of atherosclerosis and is closely linked to osteoporosis. Cellular differentiation is regulated by various microRNAs (miRs), including miR-125b, which is known to be involved in osteoblast differentiation. However, no specific miR has been defined that modulates vascular calcification. Herein, we assessed the impact of miR-125b in osteogenic transformation of vascular smooth muscle cells. Osteogenic transdifferentiation of human coronary artery smooth muscle cells was induced by osteogenic medium and enhanced the formation of mineralized matrix, resulting in a significantly higher mineral deposition after 21 days. Increased expression of miR-125b was time-dependent in human coronary artery smooth muscle cells and diminished during osteogenic transdifferentiation. At day 21, miR-125b was significantly reduced (؊42%) compared with that in the untreated control. The expression of miR-processing enzymes, RNase III endonucleases DICER1 and DROSHA, was also decreased. Furthermore, inhibition of endogenous miR-125b promoted osteogenic transdifferentiation, as measured by increased alkaline phosphatase activity and matrix mineralization. Expression analysis revealed the osteoblast transcription factor SP7 (osterix) as a target of miR-125b. In vivo, miR125b was decreased in calcified aortas of apolipoprotein E knockout mice. In conclusion, our results suggest that miR-125b is involved in vascular calcification in vitro and in vivo, at least partially by targeting SP7. Evaluating the role of miRs in arterial calcification in vivo may have important therapeutic implications.

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Oxidant Generation Predominates Around Calcifying Foci and Enhances Progression of Aortic Valve Calcification

Cited by 182 publications

References 41 publications

Oxidative Stress Induces Vascular Calcification through Modulation of the Osteogenic Transcription Factor Runx2 by AKT Signaling

Oxidative Stress Induces Vascular Calcification through Modulation of the Osteogenic Transcription Factor Runx2 by AKT Signaling

Oxidized low-density lipoprotein and β-glycerophosphate synergistically induce endothelial progenitor cell ossification

miR-125b Regulates Calcification of Vascular Smooth Muscle Cells

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