Determine exogenous humanDDAH2gene function in rabbit bone marrow-derived endothelial progenitor cells in vitro

Dimethyloxalylglycine Attenuates Steroid-Associated Endothelial Progenitor Cell Impairment and Osteonecrosis of the Femoral Head by Regulating the HIF-1α Signaling Pathway

Endothelial impairment and dysfunction are closely related to the pathogenesis of steroid-associated osteonecrosis of the femoral head (SONFH). Recent studies have showed that hypoxia inducible factor-1α (HIF-1α) plays a crucial role in endothelial homeostasis maintenance. Dimethyloxalylglycine (DMOG) could suppress HIF-1 degradation and result in nucleus stabilization by repressing prolyl hydroxylase domain (PHD) enzymatic activity. Our results showed that methylprednisolone (MPS) remarkably undermined biological function of endothelial progenitor cells (EPC) by inhibiting colony formation, migration, angiogenesis, and stimulating senescence of EPCs, while DMOG treatment alleviated these effects by promoting HIF-1α signaling pathway, as evidenced by senescence-associated β-galactosidase (SA-β-Gal) staining, colony-forming unit, matrigel tube formation, and transwell assays. The levels of proteins related to angiogenesis were determined by ELISA and Western blotting. In addition, active HIF-1α bolstered the targeting and homing of endogenous EPCs to the injured endothelium in the femoral head. Histopathologically, our in vivo study showed that DMOG not only alleviated glucocorticoid-induced osteonecrosis but also promoted angiogenesis and osteogenesis in the femoral head as detected by microcomputed tomography (Micro-CT) analysis and histological staining of OCN, TRAP, and Factor Ⅷ. However, all of these effects were impaired by an HIF-1α inhibitor. These findings demonstrate that targeting HIF-1α in EPCs may constitute a novel therapeutic approach for the treatment of SONFH.

Comparative Analysis of the Rabbit Endothelial Progenitor Cells from Bone Marrow and Peripheral Blood Treated with Selenium Nanoparticles

BACKGROUND

Selenium Nanoparticles (Se-NPs) are known for their antioxidant and anti-inflammatory activities, which are effective in preventing oxidative damage and improving physiological processes.

OBJECTIVES

This study aimed at investigating the effects of biosynthesized Se-NPs on bone marrow-derived Endothelial Progenitor Cells (bone marrow-derived EPCs) and blood-derived endothelial progenitor cells (blood-derived EPCs) isolated from rabbits in vitro.

METHODS

The cultured EPCs incubated with biosynthesized Se-NPs at the concentrations of 0.19, 0.38, 0.76, 1.71, 3.42, 7.03, 14.25, 28.50, 57, 114, and 228μg/ml for 48h. After screening the proliferative potential of the Se-NPs by the MTT assay, the best concentrations were selected for Real-Time quantitative Polymerase Chain Reaction (RT-qPCR). Real-time quantification of Vascular Cell Adhesion Molecule 1 (VCAM-1), lectin-like oxidized Low-Density Lipoprotein (LDL) receptor-1 (LOX-1), endothelial Nitric Oxide Synthase (eNOS), and Monocyte Chemoattractant Protein-1 (MCP-1) gene expressions were analyzed by normalizing with Glyceraldehyde- 3-Phosphate Dehydrogenase (GAPDH) as an endogenous reference gene.

RESULTS

Blood-derived EPCs and bone marrow-derived EPCs showed morphological differences before treatment in vitro. Se-NPs treated EPCs indicated a significant dose-dependent proliferative activity (p<0.01). In general, the expression levels of VCAM-1, LOX-1, and MCP-1 mRNA were significantly decreased (p<0.01), whereas that of the eNOS expression was significantly increased at the concentrations of 7.3 and 14.25μg/ml (p<0.01). Although the expressions of MCP-1, LOX-1, and eNOS mRNA were decreased at certain concentrations of Se-NPs (p<0.01 and p<0.05, respectively) in the treated bone marrow-derived EPCs, no significant differences were observed in the VCAM-1 mRNA expression levels in bone marrow-derived EPCs compared with the control group (p>0.05).

CONCLUSION

This was the first report to demonstrate the effects of Se-NPs on proliferative, anti-oxidative, and anti-inflammatory activities for bone marrow-derived EPCs and blood-derived EPCs. Our findings suggested that Se-NPs could be considered as an effective agent that may ameliorate vascular problems.

Treatment of atherosclerosis through transplantation of endothelial progenitor cells overexpressing dimethylarginine dimethylaminohydrolase (DDAH) in rabbits

BACKGROUND

Endothelial dysfunction is a key event in the development of vascular diseases, including atherosclerosis. Endothelial progenitor cells (EPCs) play an important role in vascular repair. Decreased dimethylarginine dimethylaminohydrolase (DDAH) activity is observed in several pathological conditions, and it is associated with an increased risk of vascular disease. We hypothesized that bone marrow-derived EPCs and combination therapy with DDAH2-EPCs could reduce plaque size and ameliorate endothelial dysfunction in an atherosclerosis rabbit model.

METHOD

Four groups of rabbits (n = 8 per group) were subjected to a hyperlipidemic diet for a month. After establishing the atherosclerosis model, rabbits received 4 × 10⁶ EPC, EPCs expressing DDAH2, through femoral vein injection, or saline (the control group with basic food and the untreated group). One month after transplantation, plaque thickness, endothelial function, oxidative stress, and inflammatory mRNAs, DDAH, and eNOS function were assessed.

RESULTS

DDAH2-EPCs transplantation (p < 0.05) and EPCs transplantation (p < 0.05) were both associated with a reduction in plaque size compared to the control saline injection. The antiproliferative and antiatherogenic effects of EPCs were further enhanced by the overexpression of DDAH2 (p < 0.05, DDAH2-EPCs vs. EPCs). Furthermore, DDAH2-EPCs transplantation significantly increased endothelium integrity compared to the EPCs transplantation.

CONCLUSION

Transplantation of EPCs overexpressing DDAH2 may enhance the repair of injured endothelium by reducing inflammation and restoring endothelial function. Therefore, pCMV6-mediated DDAH2 gene-transfected EPCs are a potentially valuable tool for the treatment of atherosclerosis.

MiR-92a regulates endothelial progenitor cells (EPCs) by targeting GDF11 via activate SMAD2/3/FAK/Akt/eNOS pathway

Background

The effects of miR-92a on EPCs are still poorly elucidated. This study aimed to investigate the effects of miR-92a on EPCs (Endothelial progenitor cells) in a model of hypoxia (HO) or high glucose (HG)-induced EPCs injury by targeting GDF11 (Differentiation growth factor 11).

Methods

The effects of miR-92a on EPCs subjected to HO or HG were investigated firstly. Subsequently, the action mechanism of miR-92a on EPCs by targeting GDF11 was elucidated. Proliferation, apoptosis, migration, angiogenesis was measured with MTT, flow cytometry, transwell, tube formation respectively. After 24 h, levels of reactive oxygen species (ROS) were measured by fluorescence intensity. LDH and NO (nitric oxide) levels were determined by ELISA. The expression of FLK-1 (fetal liver kinase 1) and vWF (von Willebrand factor) was detected by immunofluorescence. mRNA and protein expression levels were examined using PCR and western blotting respectively. The interaction between miR-92a and GDF11 was evaluated by dual-luciferase reporter assay.

Results

Our results showed that HO or HG increased apoptosis, production of LDH and generation of ROS, but decreased the ability of migration and tube formation and generation of NO in EPCs; inhibiting of miR-92a decreased HO or HG-induced injury of EPCs, whereas miR-92a over-expression had the opposite effect; the protective effects induced by inhibiting of miR-92a on EPCs could be reversed by GDF11 siRNA and the harmful effects induced by over-expression of miR-92a could be rescued by over-expression of GDF11, which showed that the harmful effects of miR-92a be related to its inhibition of GDF11 and subsequent inactivation of the SMAD2/3/FAK/Akt/eNOS signaling pathway.

Conclusions

Inhibiting miR-92a can protect EPCs from HO or HG-induced injury. The effect of miR-92a on EPCs are mediated by regulating of GDF11 and downstream SMAD2/3/FAK/Akt/eNOS signaling pathway.