| 1. |
- Aldi, Silvia, et al.
(författare)
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Dual roles of heparanase in human carotid plaque calcification
- 2019
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Ingår i: Atherosclerosis. - : ELSEVIER IRELAND LTD. - 0021-9150 .- 1879-1484. ; 283, s. 127-136
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Calcification is a hallmark of advanced atherosclerosis and an active process akin to bone remodeling. Heparanase (HPSE) is an endo-beta-glucuronidase, which cleaves glycosaminoglycan chains of heparan sulfate proteoglycans. The role of HPSE is controversial in osteogenesis and bone remodeling while it is unexplored in vascular calcification. Previously, we reported upregulation of HPSE in human carotid endarterectomies from symptomatic patients and showed correlation of HPSE expression with markers of inflammation and increased thrombogenicity. The present aim is to investigate HPSE expression in relation to genes associated with osteogenesis and osteolysis and the effect of elevated HPSE expression on calcification and osteolysis in vitro.Methods: Transcriptomic and immunohistochemical analyses were performed using the Biobank of Karolinska Endarterectomies (BiKE). In vitro calcification and osteolysis were analysed in human carotid smooth muscle cells overexpressing HPSE and bone marrow-derived osteoclasts from HPSE-transgenic mice respectively.Results: HPSE expression correlated primarily with genes coupled to osteoclast differentiation and function in human carotid atheromas. HPSE was expressed in osteoclast-like cells in atherosclerotic lesions, and HPSE-transgenic bone marrow-derived osteoclasts displayed a higher osteolytic activity compared to wild-type cells. Contrarily, human carotid SMCs with an elevated HPSE expression demonstrated markedly increased mineralization upon osteogenic differentiation.Conclusions: We suggest that HPSE may have dual functions in vascular calcification, depending on the stage of the disease and presence of inflammatory cells. While HPSE plausibly enhances mineralization and osteogenic differentiation of vascular smooth muscle cells, it is associated with inflammation-induced osteoclast differentiation and activity in advanced atherosclerotic plaques.
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| 2. |
- Karlöf, Eva, et al.
(författare)
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Correlation of computed tomography with carotid plaque transcriptomes associates calcification with lesion-stabilization
- 2019
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Ingår i: Atherosclerosis. - Stockholm : ELSEVIER IRELAND LTD. - 0021-9150 .- 1879-1484. ; 288, s. 175-185
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Unstable carotid atherosclerosis causes stroke, but methods to identify patients and lesions at risk are lacking. We recently found enrichment of genes associated with calcification in carotid plaques from asymptomatic patients. Here, we hypothesized that calcification represents a stabilising feature of plaques and investigated how macro-calcification, as estimated by computed tomography (CT), correlates with gene expression profiles in lesions. Methods: Plaque calcification was measured in pre-operative CT angiographies. Plaques were sorted into high- and low-calcified, profiled with microarrays, followed by bioinformatic analyses. Immunohistochemistry and qPCR were performed to evaluate the findings in plaques and arteries with medial calcification from chronic kidney disease patients. Results: Smooth muscle cell (SMC) markers were upregulated in high-calcified plaques and calcified plaques from symptomatic patients, whereas macrophage markers were downregulated. The most enriched processes in high-calcified plaques were related to SMCs and extracellular matrix (ECM) organization, while inflammation, lipid transport and chemokine signaling were repressed. These findings were confirmed in arteries with high medial calcification. Proteoglycan 4 (PRG4) was identified as the most upregulated gene in association with plaque calcification and found in the ECM, SMA+ and CD68+/TRAP + cells. Conclusions: Macro-calcification in carotid lesions correlated with a transcriptional profile typical for stable plaques, with altered SMC phenotype and ECM composition and repressed inflammation. PRG4, previously not described in atherosclerosis, was enriched in the calcified ECM and localized to activated macrophages and smooth muscle-like cells. This study strengthens the notion that assessment of calcification may aid evaluation of plaque phenotype and stroke risk.
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| 3. |
- Swärd, Karl, et al.
(författare)
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Identification of the intermediate filament protein synemin/SYNM as a target of myocardin family coactivators
- 2019
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Ingår i: American Journal of Physiology - Cell Physiology. - : American Physiological Society. - 0363-6143 .- 1522-1563. ; 317:6, s. 1128-1142
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Tidskriftsartikel (refereegranskat)abstract
- Myocardin (MYOCD) is a critical regulator of smooth muscle cell (SMC) differentiation, but its transcriptional targets remain to be exhaustively characterized, especially at the protein level. Here we leveraged human RNA and protein expression data to identify novel potential MYOCD targets. Using correlation analyses we found several targets that we could confirm at the protein level, including SORBS1, SLMAP, SYNM, and MCAM. We focused on SYNM, which encodes the intermediate filament protein synemin. SYNM rivalled smooth muscle myosin (MYH11) for SMC specificity and was controlled at the mRNA and protein levels by all myocardin-related transcription factors (MRTFs: MYOCD, MRTF-A/MKL1, and MRTF-B/MKL2). MRTF activity is regulated by the ratio of filamentous to globular actin, and SYNM was accordingly reduced by interventions that depolymerize actin, such as latrunculin treatment and overexpression of constitutively active cofilin. Many MRTF target genes depend on serum response factor (SRF), but SYNM lacked SRF-binding motifs in its proximal promoter, which was not directly regulated by MYOCD. Furthermore, SYNM resisted SRF silencing, yet the time course of induction closely paralleled that of the SRF-dependent target gene ACTA2. SYNM was repressed by the ternary complex factor (TCF) FLI1 and was increased in mouse embryonic fibroblasts lacking three classical TCFs (ELK1, ELK3, and ELK4). Imaging showed colocalization of SYNM with the intermediate filament proteins desmin and vimentin, and MRTF-A/MKL1 increased SYNM-containing intermediate filaments in SMCs. These studies identify SYNM as a novel SRF-independent target of myocardin that is abundantly expressed in all SMCs.
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