SDF-1 promotes ox-LDL induced vascular smooth muscle cell proliferation

Comparison of Gelatin/Polylysine- and Silk Fibroin/SDF-1α-Coated Mesenchymal Stem Cell-Seeded Intracranial Stents

Endothelialization of the aneurysmal neck is essential for aneurysm healing after endovascular treatment. Mesenchymal stem cell (MSC)-seeded stents can promote aneurysm repair. The biological effects of coated and uncoated nitinol intracranial stents seeded with MSCs on vascular cells and macrophage proliferation and inflammation are investigated. Two stent coatings that exert pro-aggregation effects on MSCs via different mechanisms are examined: gelatin/polylysine (G/PLL), which enhances cell adhesion, and silk fibroin/SDF-1α (SF/SDF-1α), which enhances chemotaxis. The aim is to explore the feasibility of MSC-seeded coated stents in the treatment of intracranial aneurysms. The G/PLL coating provides the highest cytocompatibility and blood compatibility substrate for MSCs and vascular cells and promotes cell adhesion and proliferation. Moreover, it enhances MSC secretion and regulation of vascular cell and macrophage proliferation and chemotaxis. Although the SF/SDF-1α coating promotes MSC secretion and vascular cell chemotaxis, it induces a greater degree of macrophage proliferation, chemotaxis, and secretion of pro-inflammatory factors. MSC-seeded stents coated with G/PLL may benefit stent surface endothelialization and reduce the inflammatory response after endovascular treatment of intracranial aneurysm. These effects may improve aneurysm healing and increase the cure rate.

Myristicin regulates proliferation and apoptosis in oxidized low-density lipoprotein-stimulated human vascular smooth muscle cells and human umbilical vein endothelial cells by regulating the PI3K/Akt/NF-κB signalling pathway

CONTEXT

Atherosclerosis (AS) is a chronic inflammatory disease. Human vascular smooth muscle cell (hVSMC) accumulation and human umbilical vein endothelial cell (HUVEC) dysfunction are associated with the pathogenesis of AS. This study explores whether myristicin plays a protective role in AS.

MATERIALS AND METHODS

hVSMCs and HUVECs were stimulated with 100 μg/mL oxidized low-density lipoprotein (ox-LDL) to establish a cellular model of AS. Cell viability, lactate dehydrogenase (LDH) release and cell apoptosis were evaluated using MTT, LDH and flow cytometry assays, respectively. Cell migration and inflammatory cytokine release were assessed using Transwell assay and ELISA.

RESULTS

Myristicin (5, 10, 25, and 50 μM) had no obvious effect on cell viability or the activity of LDH in hVSMCs, while 100 and 200 μM myristicin markedly suppressed hVSMCs viability and increased LDH release. Myristicin had no obvious effect on cell viability or the activity of LDH in HUVECs. Myristicin inhibited viability and increased apoptosis in ox-LDL-treated hVSMCs, but was associated with increased proliferation and inhibited apoptosis in HUVECs stimulated by ox-LDL. Additionally, myristicin markedly suppressed ox-LDL-induced hVSMCs migration and the release of inflammatory cytokines, including MCP-1, IL-6, VCAM-1 and ICAM-1, in HUVECs. Results also demonstrated that the promoting effects of ox-LDL on the PI3K/Akt and NF-κB signalling pathway in both hVSMCs and HUVECs were abolished by treatment with myristicin.

DISCUSSION AND CONCLUSIONS

Myristicin regulated proliferation and apoptosis by regulating the PI3K/Akt/NF-κB signalling pathway in ox-LDL-stimulated hVSMCs and HUVECs. Thus, myristicin may be used as a new potential drug for AS treatment.

Systemic Profile of Cytokines in Arteriovenous Fistula Patients and Their Associations with Maturation Failure

Background

Systemic cytokines are elevated in patients with chronic kidney disease (CKD) and on hemodialysis compared with the general population. However, whether cytokine levels interfere with vascular remodeling, increasing the risk of arteriovenous fistula (AVF) failure, remains unknown.

Methods

This is a case-control study of 64 patients who underwent surgery for AVF creation (32 with AVF maturation failure and 32 matching controls with successful maturation). A total of 74 cytokines, including chemokines, interferons, interleukins, and growth factors, were measured in preoperative plasma samples using multiplex assays. Sixty-two patients were included in the statistical analyses. Associations with AVF failure were assessed using paired comparisons and conditional logistic regressions accounting for paired strata.

Results

Seven cytokines were significantly higher in patients with AVF maturation failure than in matching controls (G-CSF, IL-6, MDC, RANTES, SDF-1α/β, TGFα, and TPO). Of these, G-CSF (odds ratio [OR]=1.71; 95% confidence interval [95% CI], 1.05 to 2.79 per 10 pg/ml), MDC (OR=1.60, 95% CI, 1.08 to 2.38 per 100 pg/ml), RANTES (OR=1.55, 95% CI, 1.10 to 2.17 per 100 pg/ml), SDF-1α/β (OR=1.18, 95% CI, 1.04 to 1.33 per 1000 pg/ml), and TGFα (OR=1.39, 95% CI 1.003, 1.92 per 1 pg/ml) showed an incremental association by logistic regression.

Conclusions

This study identified a profile of plasma cytokines associated with adverse maturation outcomes in AVFs. These findings may open the doors for future therapeutics and markers for risk stratification.

Foam cells promote atherosclerosis progression by releasing CXCL12

BACKGROUND

Atherosclerosis (AS) is a chronic inflammatory disease that contributes to multiple cardiovascular diseases (CVDs), and foam cell formation plays important roles in the progression of AS. There is an urgent need to identify new molecular targets for treating AS, and thereby improve the quality of life and reduce the financial burden of individuals with CVD.

METHODS

An in vitro model of AS was generated by treating THP-1 cells and human aortic vascular smooth muscle cells (HA-VSMCs) with oxidized low-density lipoproteins (ox-LDLs). HA-VSMC proliferation and foam cell formation were detected by the MTT assay and Oil Red O staining. C-X-C motif chemokine 12 (CXCL12) expression was suppressed by siRNA. An AS rat model was established by feeding rats a high-fat diet and vitamin D2 for 3 weeks. Histopathology examinations were conducted by Hematoxylin and Eosin (H&E) staining and the levels ionized calcium-binding adapter molecule 1 (IBA1) and α smooth muscle actin (α-SMA) expression were determined by ELISA assays and immunohistochemistry.

RESULTS

An in vitro model of AS was established with THP-1 cells. CXCL12 expression in the model THP-1 cells was significantly increased when compared with its expression in control cells. Suppression of CXCL12 expression reduced the progression of AS in the cell model. Moreover, CXCL12 promoted AS in the in vivo rat model.

CONCLUSION

Our results suggest that CXCL12 plays an important role in promoting the progression of AS. Furthermore, inhibition of CXCL12 might suppress the development of AS by inhibiting HA-VSMC proliferation and their transformation to foam cells.

Potential cell-specific functions of CXCR4 in atherosclerosis

Der Chemokinrezeptor CXCR4 and sein Ligand CXCL12 bilden eine wichtige Achse in der Regulation von Zellfunktionen bei normaler Homöostase und bei Erkrankungen. Zusätzlich kann der atypische CXCL12 Rezeptor CXCR7 die Verfügbarkeit und Funktion von CXCL12 modulieren. Neben ihrer Rolle in der Mobilisierung von Stamm- und Vorläuferzellen, können CXCR4 und CXCL12 auch die Entwicklung der Atherosklerose über verschiedene Zellfunktionen beeinflussen. Dieser kurze Übersichtsartikel fasst das gegenwärtige Wissen zu den zellspezifischen Funktionen von CXCL12 und den Rezeptoren CXCR4 und CXCR7 mit möglichen Implikationen für die Entstehung und Progression der Atherosklerose zusammen

Chemokine-Like Receptor 1 Regulates the Proliferation and Migration of Vascular Smooth Muscle Cells

Background

We aimed to explore how chemokine-like receptor 1 (CMKLR1) influences the proliferation and migration of vascular smooth muscle cells (VSMCs).

Material/Methods

Normal VSMCs, negative control VSMCs interfered by CMKLR1 gene, and VSMCs with stable knockdown of CMKLR1 gene were divided into the control group, PDGF group, negative-shRNA group, and CMKLR1-shRNA group. Both cell number counting and BrdU incorporation assays were employed to investigate the proliferation status of VSMCs. Transwell migration assay was used to measure the migration status of VSMCs. Inflammation markers, including cytokines IL-1β, IL-6, TNF-α, and chemokines MCP-1 in VSMCs, were detected by real-time quantitative RT-PCR. Western blotting assay was used to detect protein expressions of the MAPK pathway in VSMCs.

Results

The number of VSMCs and the OD value of BrdU in PDGF group were significantly higher than those in the control group (both P<0.05). Compared with the control and negative-shRNA group, the CMKLR1-shRNA group exhibited significantly reduced VSMCs number and BrdU OD value (both P<0.05). Transwell migration assay indicated that PDGF-BB promoted whereas CMKLR1-shRNA inhibited the migration of VSMCs. The expression of IL-1β, IL-6, TNF-α, and MCP-1 were up-regulated in the PDGF group but down-regulated in the CMKLR1-shRNA group. Compared with normal VSMCs, the protein level of p-ERK1/2 was up-regulated in VSMCs treated with PDGF-BB, while it was down-regulated in the CMKLR1-shRNA group.

Conclusions

CMKLR1 exacerbated the proliferation and migration of VSMCs by activating ERK1/2.

Chemokines and their receptors in Atherosclerosis

Atherosclerosis, a chronic inflammatory disease of the medium- and large-sized arteries, is the main underlying cause of cardiovascular diseases (CVDs) most often leading to a myocardial infarction or stroke. However, atherosclerosis can also develop without this clinical manifestation. The pathophysiology of atherosclerosis is very complex and consists of many cells and molecules interacting with each other. Over the last years, chemokines (small 8-12 kDa cytokines with chemotactic properties) have been identified as key players in atherogenesis. However, this remains a very active and dynamic field of research. Here, we will give an overview of the current knowledge about the involvement of chemokines in all phases of atherosclerotic lesion development. Furthermore, we will focus on two chemokines that recently have been associated with atherogenesis, CXCL12, and macrophage migration inhibitory factor (MIF). Both chemokines play a crucial role in leukocyte recruitment and arrest, a critical step in atherosclerosis development. MIF has shown to be a more pro-inflammatory and thus pro-atherogenic chemokine, instead CXCL12 seems to have a more protective function. However, results about this protective role are still quite debatable. Future research will further elucidate the precise role of these chemokines in atherosclerosis and determine the potential of chemokine-based therapies.

The Dipeptidyl Peptidase Family, Prolyl Oligopeptidase, and Prolyl Carboxypeptidase in the Immune System and Inflammatory Disease, Including Atherosclerosis

Research from over the past 20 years has implicated dipeptidyl peptidase (DPP) IV and its family members in many processes and different pathologies of the immune system. Most research has been focused on either DPPIV or just a few of its family members. It is, however, essential to consider the entire DPP family when discussing any one of its members. There is a substantial overlap between family members in their substrate specificity, inhibitors, and functions. In this review, we provide a comprehensive discussion on the role of prolyl-specific peptidases DPPIV, FAP, DPP8, DPP9, dipeptidyl peptidase II, prolyl carboxypeptidase, and prolyl oligopeptidase in the immune system and its diseases. We highlight possible therapeutic targets for the prevention and treatment of atherosclerosis, a condition that lies at the frontier between inflammation and cardiovascular disease.

MIF and CXCL12 in Cardiovascular Diseases: Functional Differences and Similarities

Coronary artery disease (CAD) as part of the cardiovascular diseases is a pathology caused by atherosclerosis, a chronic inflammatory disease of the vessel wall characterized by a massive invasion of lipids and inflammatory cells into the inner vessel layer (intima) leading to the formation of atherosclerotic lesions; their constant growth may cause complications such as flow-limiting stenosis and plaque rupture, the latter triggering vessel occlusion through thrombus formation. Pathophysiology of CAD is complex and over the last years many players have entered the picture. One of the latter being chemokines (small 8-12 kDa cytokines) and their receptors, known to orchestrate cell chemotaxis and arrest. Here, we will focus on the chemokine CXCL12, also known as stromal cell-derived factor 1 (SDF-1) and the chemokine-like function chemokine, macrophage migration-inhibitory factor (MIF). Both are ubiquitously expressed and highly conserved proteins and play an important role in cell homeostasis, recruitment, and arrest through binding to their corresponding chemokine receptors CXCR4 (CXCL12 and MIF), ACKR3 (CXCL12), and CXCR2 (MIF). In addition, MIF also binds to the receptor CD44 and the co-receptor CD74. CXCL12 has mostly been studied for its crucial role in the homing of (hematopoietic) progenitor cells in the bone marrow and their mobilization into the periphery. In contrast to CXCL12, MIF is secreted in response to diverse inflammatory stimuli, and has been associated with a clear pro-inflammatory and pro-atherogenic role in multiple studies of patients and animal models. Ongoing research on CXCL12 points at a protective function of this chemokine in atherosclerotic lesion development. This review will focus on the role of CXCL12 and MIF and their differences and similarities in CAD of high risk patients.

The CXCL12/CXCR4 chemokine ligand/receptor axis in cardiovascular disease

The chemokine receptor CXCR4 and its ligand CXCL12 play an important homeostatic function by mediating the homing of progenitor cells in the bone marrow and regulating their mobilization into peripheral tissues upon injury or stress. Although the CXCL12/CXCR4 interaction has long been regarded as a monogamous relation, the identification of the pro-inflammatory chemokine macrophage migration inhibitory factor (MIF) as an important second ligand for CXCR4, and of CXCR7 as an alternative receptor for CXCL12, has undermined this interpretation and has considerably complicated the understanding of CXCL12/CXCR4 signaling and associated biological functions. This review aims to provide insight into the current concept of the CXCL12/CXCR4 axis in myocardial infarction (MI) and its underlying pathologies such as atherosclerosis and injury-induced vascular restenosis. It will discuss main findings from in vitro studies, animal experiments and large-scale genome-wide association studies. The importance of the CXCL12/CXCR4 axis in progenitor cell homing and mobilization will be addressed, as will be the function of CXCR4 in different cell types involved in atherosclerosis. Finally, a potential translation of current knowledge on CXCR4 into future therapeutical application will be discussed.

Oxidized low-density lipoprotein increases the proliferation and migration of human coronary artery smooth muscle cells through the upregulation of osteopontin

Smooth muscle cell (SMC) proliferation and migration are known to play a critical role in the development of atherosclerosis. Oxidized low-density lipoprotein (oxLDL) is involved in the generation of atherosclerotic lesions. Recent studies have indicated that oxLDL is a well-established risk factor for atherosclerosis that induces vascular smooth muscle cell (VSMC) proliferation and migration; however, the exact mechanisms involved have not been fully elucidated. In this study, the proliferation of human coronary artery smooth muscle cells (HCASMCs) was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell migration was determined by Transwell assay. Osteopontin (OPN), matrix metaloproteinase-9 (MMP-9) and αvβ3 integrin expression were measured by mRNA and western blot analysis. OPN and MMP-9 knockdown cells were established through transfection with OPN siRNA or MMP-9 siRNA, respectively. Our results revealed that oxLDL makredly promoted HCASMC proliferation and migration in a dose-dependent manner. Further experiments demonstrated that oxLDL upregulated the expression of OPN and oxLDL. Cell proliferation and migration were markedly reduced following the knockdown of the OPN gene in the HCASMCs. We then found that treatment with oxLDL induced a concentration-dependent increase in MMP-9 mRNA and protein levels in the HCASMCs. These effects were partially abrogated by silencing OPN expression or blocking the αvβ3 integrin pathway. Moreover, cells treated with MMP-9 siRNA or αvβ3 antibody showed lower proliferation and migration rates. This study provides direct in vitro evidence that the exposure of HCASMCs to oxLDL induces the activation of OPN, leading to higher protein levels of MMP-9, and to an increased proliferation and migration of HCASMCs.