Enhanced stem cell migration mediated by VCAM-1/VLA-4 interaction improves cardiac function in virus-induced dilated cardiomyopathy

Cutting-edge advances in modeling the blood-brain barrier and tools for its reversible permeabilization for enhanced drug delivery into the brain

The blood-brain barrier (BBB) is a sophisticated structure whose full functionality is required for maintaining the executive functions of the central nervous system (CNS). Tight control of transport across the barrier means that most drugs, particularly large size, which includes powerful biologicals, cannot reach their targets in the brain. Notwithstanding the remarkable advances in characterizing the cellular nature of the BBB and consequences of BBB dysfunction in pathology (brain metastasis, neurological diseases), it remains challenging to deliver drugs to the CNS. Herein, we outline the basic architecture and key molecular constituents of the BBB. In addition, we review the current status of approaches that are being explored to temporarily open the BBB in order to allow accumulation of therapeutics in the CNS. Undoubtedly, the major concern in field is whether it is possible to open the BBB in a meaningful way without causing negative consequences. In this context, we have also listed few other important key considerations that can improve our understanding about the dynamics of the BBB.

VCAM-1 as a predictor biomarker in cardiovascular disease

The vascular cellular adhesion molecule-1 (VCAM-1) is a protein that canonically participates in the adhesion and transmigration of leukocytes to the interstitium during inflammation. VCAM-1 expression, together with soluble VCAM-1 (sVCAM-1) induced by the shedding of VCAM-1 by metalloproteinases, have been proposed as biomarkers in immunological diseases, cancer, autoimmune myocarditis, and as predictors of mortality and morbidity in patients with chronic heart failure (HF), endothelial injury in patients with coronary artery disease, and arrhythmias. This revision aims to discuss the role of sVCAM-1 as a biomarker to predict the occurrence, development, and preservation of cardiovascular disease.

Guanxin Danshen Formulation improved the effect of mesenchymal stem cells transplantation for the treatment of myocardial infarction probably via enhancing the engraftment

Although intravenous injection is the most convenient and feasible approach for mesenchymal stem cells (MSCs) delivery, the proportion of donor stem cells in the target myocardium after transplantation is small. It is believed that TCM enhances the effect of stem cell therapy by improving the hostile microenvironment and promoting the migration and survival of stem cells. Guanxin Danshen (GXDS) formulation is one of the main prescriptions for clinical treatment of ischemic heart diseases in China. The purpose of this study was to evaluate the effects of GXDS formulation administration combined with MSCs transplantation on cardiac function improvement, apoptosis, angiogenesis and survival of transplanted cells in an acute model of acute myocardial infarction (MI). After being labeled with GFP, MSCs were transplanted via intravenous injection. Meanwhile, GXDS dripping pills were given by intragastric administration for 4 weeks from 2 days before MI. Echocardiography showed moderate improvement in cardiac function after administration of GXDS formulation or intravenous transplantation of MSCs. However, GXDS formulation combined with MSCs transplantation significantly improved cardiac function after MI. The myocardial infarct size in rats treated with MSCs was similar to that in rats treated with GXDS formulation. However, GXDS formulation combined with MSCs transplantation significantly reduced infarction area. In addition, GXDS formulation combined with MSCs transplantation not only decreased cell apoptosis according to the TUNEL staining, but also enhanced angiogenesis in the peri-infarction and infarction area. Interestingly, the use of GXDS formulation increased the number of injected MSCs in the infarct area. Furthermore, GXDS formulation combined with MSCs transplantation increased SDF-1 levels in the infarcted area, but did not affect the expression of YAP. Our study provided a more feasible and accessible strategy to enhance the migration of stem cells after intravenous injection by oral administration of GXDS formulation. The combination of GXDS formulation and stem cell therapy has practical significance and application prospects in the treatment of ischemic cardiomyopathy such as MI.

Anti-VCAM 1 Antibody-Coated Mesenchymal Stromal Cells Attenuate Experimental Colitis via Immunomodulation

Background

The treatment of inflammatory bowel disease (IBD) is still not satisfactory and novel technologies are clinically needed. This study aimed to examine the effect of mesenchymal stromal cells (MSCs) coated with the anti-vascular cell adhesion molecule 1 (VCAM 1) antibody on experimental colitis.

Material/Methods

The antibody was coated onto the MSCs isolated from male BALB/C mice to generate anti-VCAM 1 antibody-coated MSC (V-MSC). The Transwell assay was used to detect migration rate. 2,4,6-trinitrobenzenesulfonic acid (TNBS) was used to generate experimental colitis. MSCs were injected intravenously into experimental models. Weight changes, disease activity index, and histological changes were evaluated. The SRY gene were used for cell tracking. Expression of Ki67 and claudin 1 was used to measure local repair using immunohistochemistry. T helper (Th)1, Th2, Th17, and T regulatory cells were counted.

Results

V-MSCs were successfully generated through coating MSCs with VCAM1 antibody. Analysis showed that the V-MSCs had similar surface types and differentiation as uncoated MSCs. Transwell assays showed that V-MSCs had higher migration rate than MSCs. After injection of V-MSCs, the expression of the SRY gene was enhanced in diseased colon and all indices (including weight changes, DAI score, histological changes, and the expressions of Ki67 and claudin 1) recovered rapidly. The ratio of proinflammatory Th1 and Th17 cells decreased, but the ratio of anti-inflammatory Th2 and Treg cells increased after the treatment.

Conclusions

V-MSCs enhance homing and modulating immune balance in the experimental colitis, suggesting that they are potentially useful for treating inflammatory bowel disease or other immune diseases.

Longitudinal 18F-FDG PET imaging in a rat model of autoimmune myocarditis

AIMS

Although mortality rate is very high, diagnosis of acute myocarditis remains challenging with conventional tests. We aimed to elucidate the potential role of longitudinal 2-Deoxy-2-18F-fluoro-D-glucose (18F-FDG) positron emission tomography (PET) inflammation monitoring in a rat model of experimental autoimmune myocarditis.

METHODS AND RESULTS

Autoimmune myocarditis was induced in Lewis rats by immunizing with porcine cardiac myosin emulsified in complete Freund's adjuvant. Time course of disease was assessed by longitudinal 18F-FDG PET imaging. A correlative analysis between in- and ex vivo18F-FDG signalling and macrophage infiltration using CD68 staining was conducted. Finally, immunohistochemistry analysis of the cell-adhesion markers CD34 and CD44 was performed at different disease stages determined by longitudinal 18F-FDG PET imaging. After immunization, myocarditis rats revealed a temporal increase in 18F-FDG uptake (peaked at week 3), which was followed by a rapid decline thereafter. Localization of CD68 positive cells was well correlated with in vivo18F-FDG PET signalling (R2 = 0.92) as well as with ex vivo18F-FDG autoradiography (R2 = 0.9, P < 0.001, respectively). CD44 positivity was primarily observed at tissue samples obtained at acute phase (i.e. at peak 18F-FDG uptake), while CD34-positive staining areas were predominantly identified in samples harvested at both sub-acute and chronic phases (i.e. at 18F-FDG decrease).

CONCLUSION

18F-FDG PET imaging can provide non-invasive serial monitoring of cardiac inflammation in a rat model of acute myocarditis.

Overexpression of VLA-4 in glial-restricted precursors enhances their endothelial docking and induces diapedesis in a mouse stroke model

The loss of oligodendrocytes after stroke is one of the major causes of secondary injury. Glial-restricted progenitors (GRPs) have remylenating potential after intraparenchymal cerebral transplantation. The intraarterial (IA) injection route is an attractive gateway for global brain delivery, but, after IA infusion, naive GRPs fail to bind to the cerebral vasculature. The aim of this study was to test whether overexpression of Very Late Antigen-4 (VLA-4) increases endothelial docking and cerebral homing of GRPs in a stroke model. Mouse GRPs were co-transfected with DNA plasmids encoding VLA-4 subunits (α4, β1). The adhesion capacity and migration were assessed using a microfluidic assay. In vivo imaging of the docking and homing of IA-infused cells was performed using two-photon microscopy in a mouse middle cerebral artery occlusion (MCAO) model. Compared to naïve GRPs, transfection of GRPs with VLA-4 resulted in >60% higher adhesion (p < 0.05) to both purified Vascular Cell Adhesion Molecule-11 (VCAM-11) and TNFα-induced endothelial VCAM-1. VLA-4⁺GRPs displayed a higher migration in response to a chemoattractant gradient. Following IA infusion, VLA-4⁺GRPs adhered to the vasculature at three-fold greater numbers than naïve GRPs. Multi-photon imaging confirmed that VLA-4 overexpression increases the efficiency of GRP docking and leads to diapedesis after IA transplantation. This strategy may be further exploited to increase the efficacy of cellular therapeutics.

Increased Mobilization of CD45+CD34+VLA-4+ Cells in Acute Viral Myocarditis Induced by Coxsackievirus B3

OBJECTIVES

Bone marrow-derived cells (BMCs) have recently been identified to play a vital role in repairing damaged myocardium; however, it is not known whether or not mobilization of BMCs is involved in the pathogenesis of acute viral myocarditis (VMC). Thus, we analyzed the expression of CD45+CD34+VLA-4+ cells and vascular cell adhesion protein-1 (VCAM-1) in a murine model of acute VMC.

METHODS

Male BALB/c mice were intraperitoneally infected with coxsackievirus B3 to establish acute VMC. The frequency of CD45+CD34+VLA-4+ cells in the heart, peripheral blood, and bone marrow was examined by flow cytometry 3, 7, 14, and 28 days after injection. Cardiac VCAM-1 and pathology scores were determined by immunohistochemistry, and myocardial VCAM-1, IL-1β, and TNF-α were analyzed by RT-PCR and Western blot.

RESULTS

In mice with acute VMC, the CD45+CD34+VLA-4+ cell population in the heart was significantly increased by day 7 and then decreased; in contrast, the CD45+CD34+VLA-4+ cell population decreased in the bone marrow and peripheral blood by day 3 and then increased. High expression of VCAM-1 was detected in the heart in parallel with CD45+CD34+VLA-4+ cell expression.

CONCLUSIONS

In mice with acute VMC, VCAM-1-induced CD45+CD34+VLA-4+ cell mobilization into the injured heart is involved in the repair of injured myocardium.

Gene expression profiling reveals genes and transcription factors associated with dilated and ischemic cardiomyopathies

AIMS

Dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) can cause heart failure, and this study aims to identify genes and transcription factors (TFs) associated with DCM and ICM.

METHODS

Gene expression dataset GSE42955 was generated from GEO database, and it contained 12 DCM, 12 ICM, and 5 control samples. Differentially expressed genes (DEGs) were identified between DCM (or ICM) and controls. Gene functions were investigated, and their associations were analyzed using Enrichmentmap plugin in Cytoscape. Protein-protein interactions (PPIs) between DEGs were determined, and DEGs with high degree were defined as key DEGs. Potential TFs of key DEGs were predicted using iRegulon plugin. Common DEGs were found, and their functional interactions were investigated using GeneMANIA.

RESULTS

A total of 362 and 300 DEGs were respectively identified for DCM and ICM in comparison with controls, and these DEGs mainly participated in similar functions about extracellular region, membrane, immune process, and defense response. PPI networks were respectively constructed for DCM and ICM, and 26 key DEGs (e.g. CXCL10, IL6, TLR3, and VCAM1) were found, which might be targeted by 35 TFs (e.g. IRF1). Besides, 47 common up-regulated DEGs were found, which participated in 14 pathways like Apoptosis, Collagen formation, as well as 127 common down-regulated DEGs that involved in 20 pathways like Adaptive immune system, Interferon γ signaling (e.g. IRF1, VCAM1), and Toll-like receptor signaling pathway (e.g. CXCL10, IL6, TLR3).

CONCLUSION

DCM and ICM may share similar mechanism, and TFs (e.g. IRF1) play crucial roles in their development via regulating gene expression.

Soluble Vascular Cell Adhesion Molecule-1 (VCAM-1) as a Biomarker in the Mouse Model of Experimental Autoimmune Myocarditis (EAM)

Vascular cell adhesion molecule-1 (VCAM-1) is strongly upregulated in hearts of mice with coxsackie virus-induced as well as in patients with viral infection-triggered dilated cardiomyopathy. Nevertheless, the role of its soluble form as a biomarker in inflammatory heart diseases remains unclear. Therefore, we investigated whether plasma levels of soluble VCAM-1 (sVCAM-1) directly correlated with disease activity and progression of cardiac dysfunction in the mouse model of experimental autoimmune myocarditis (EAM). EAM was induced by immunization of BALB/c mice with heart-specific myosin-alpha heavy chain peptide together with complete Freund`s adjuvant. ELISA revealed strong expression of cardiac VCAM-1 (cVCAM-1) throughout the course of EAM in immunized mice compared to control animals. Furthermore, sVCAM-1 was elevated in the plasma of immunized compared to control mice at acute and chronic stages of the disease. sVCAM-1 did not correlate with the degree of acute cardiac inflammation analyzed by histology or cardiac cytokine expression investigated by ELISA. Nevertheless, heart to body weight ratio correlated significantly with sVCAM-1 at chronic stages of EAM. Cardiac systolic dysfunction studied with positron emission tomography indicated a weak relationship with sVCAM-1 at the chronic stage of the disease. Our data provide evidence that plasma levels of sVCAM-1 are elevated throughout all stages of the disease but showed no strong correlation with the severity of EAM.

Attenuation of cardiac hypertrophy by G-CSF is associated with enhanced migration of bone marrow-derived cells

Granulocyte-colony stimulating factor (G-CSF) has been shown to promote mobilization of bone marrow-derived stem cells (BMCs) into the bloodstream associated with improved survival and cardiac function after myocardial infarction. Therefore, the aim of the present study was to investigate whether G-CSF is able to attenuate cardiac remodelling in a mouse model of pressure-induced LV hypertrophy focusing on mobilization and migration of BMCs. LV hypertrophy was induced by transverse aortic constriction (TAC) in C57BL/6J mice. Four weeks after TAC procedure. Mice were treated with G-CSF (100 μg/kg/day; Amgen Biologicals) for 2 weeks. The number of migrated BMCs in the heart was analysed by flow cytometry. mRNA expression and protein level of different growth factors in the myocardium were investigated by RT-PCR and ELISA. Functional analyses assessed by echocardiography and immunohistochemical analysis were performed 8 weeks after TAC procedure. G-CSF-treated animals revealed enhanced homing of VLA-4⁺ and c-kit⁺ BMCs associated with increased mRNA expression and protein level of the corresponding homing factors Vascular cell adhesion protein 1 and Stem cell factor in the hypertrophic myocardium. Functionally, G-CSF significantly preserved LV function after TAC procedure, which was associated with a significantly reduced area of fibrosis compared to control animals. Furthermore, G-CSF-treated animals revealed a significant improvement of survival after TAC procedure. In summary, G-CSF treatment preserves cardiac function and is able to diminish cardiac fibrosis after induction of LV hypertrophy associated with increased homing of VLA-4⁺ and c-kit⁺ BMCs and enhanced expression of their respective homing factors VCAM-1 and SCF.

Impact of parathyroid hormone on bone marrow-derived stem cell mobilization and migration

Parathyroid hormone (PTH) is well-known as the principal regulator of calcium homeostasis in the human body and controls bone metabolism via actions on the survival and activation of osteoblasts. The intermittent administration of PTH has been shown to stimulate bone production in mice and men and therefore PTH administration has been recently approved for the treatment of osteoporosis. Besides to its physiological role in bone remodelling PTH has been demonstrated to influence and expand the bone marrow stem cell niche where hematopoietic stem cells, capable of both self-renewal and differentiation, reside. Moreover, intermittent PTH treatment is capable to induce mobilization of progenitor cells from the bone marrow into the bloodstream. This novel function of PTH on modulating the activity of the stem cell niche in the bone marrow as well as on mobilization and regeneration of bone marrow-derived stem cells offers new therapeutic options in bone marrow and stem cell transplantation as well as in the field of ischemic disorders.

Advanced age impairs cardioprotective function of mesenchymal stem cell transplantation from patients to myocardially infarcted rats

OBJECTIVES

Mesenchymal stem cells (MSCs) have limited clinical therapeutic effects in older myocardial infarction (MI) patients. Thus, whether younger MSCs might confer greater protection is worth investigating.

METHODS

Human MSCs (hMSCs) were isolated before coronary artery bypass graft surgery and growth characteristics of hMSCs at passage 3 were observed. Vascular endothelial growth factor (VEGF) and Bcl-2 mRNA and protein expression from hMSCs were measured. In vivo, 45 adult male rats with MI were randomized to receive one of three treatments: old hMSCs, young hMSCs or culture medium (control) transplanted into infarcted myocardium. Echocardiography, TUNEL, immunohistochemistry and Western blot were used to assess results.

RESULTS

hMSC proliferation in the old group was significantly lower than the young group. VEGF decreased 35% and Bcl-2 decreased more than 60% at the mRNA level; VEGF and Bcl-2 protein were decreased in the old versus the young group. hMSC transplantation may improve cardiac function, but MSC source may affect therapeutic efficacy. Similar data were obtained from TUNEL, immunohistochemistry and Western blot.

CONCLUSION

Transplantation of hMSCs improves heart function, but proliferative ability and myocardial protection decrease with older MSCs, likely due to differences between VEGF and Bcl-2 expression and reduced anti-apoptosis.