Detection of cytokines in supernatant from hematopoietic stem/progenitor cells co-cultured with mesenchymal stem cells and endothelial progenitor cells

Role of microvascular endothelial cells on proliferation, migration and adhesion of hematopoietic stem cells

Background: The present study investigated the effects of microvascular endothelial cells (MECs) on the chemotaxis, adhesion and proliferation of bone marrow hematopoietic stem cells (HSCs) ex vivo. Methods and Results: MECs were collected from the lung tissue of C57BL/6 mice, and HSCs were isolated with immunomagnetic beads from bone marrow of GFP mice. MECs and HSCs were co-cultured with or without having direct cell–cell contact in Transwell device for the measurement of chemotaxis and adhesion of MECs to HSCs. Experimental results indicate that the penetration rate of HSCs from the Transwell upper chamber to lower chamber in ‘co-culture’ group was significantly higher than that of ‘HSC single culture’ group. Also, the HSCs in co-culture group were all adherent at 24 h, and the co-culture group with direct cell–cell contact had highest proliferation rate. The HSC number was positively correlated with vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) levels in supernatants of the culture. Conclusions: Our study reports that MECs enhance the chemotaxis, adhesion and proliferation of HSCs, which might be related to cytokines SDF-1 and VEGF secreted by MECs, and thus MECs enhance the HSC proliferation through cell–cell contact. The present study revealed the effect of MECs on HSCs, and provided a basis and direction for effective expansion of HSCs ex vivo.

Comparison of biological characteristics of mesenchymal stem cells derived from the human umbilical cord and decidua parietalis

Mesenchymal stem cells (MSCs) are derived from the mesoderm and have the self‑renewal capacity and multi‑directional differentiation potential of adult stem cells. Stem cells from different sources have different molecular and growth characteristics; therefore, the mechanisms and effects of stem cell‑mediated repair and tissue regeneration may be different. The aim of the present study was to compare the biological characteristics of MSCs derived from the umbilical cord (UC‑MSCs) and MSCs derived from the decidua parietalis (DP‑MSCs), and to provide new evidence for the selection of seed cells in regenerative medicine. Growth curves, cell doubling times, colony formation rates, immunophenotypes, differentiation capacities and secretion‑factor levels of MSCs derived from the two sources were analysed. UC‑MSCs and DP‑MSCs exhibited similar properties with regards to morphology, spiral growth, immunophenotype, and potential to differentiate into osteoblasts and adipocytes. For each cell type, the positive rates of the cell surface markers CD73, CD90 and CD105 were >95%, whereas CD34 and CD45 positive rates were <1%. Analyses of in vitro growth kinetics revealed shorter cell‑doubling times, and higher proliferative rates and colony formation rates of UC‑MSCs compared with DP‑MSCs (P<0.05). The concentration of basic fibroblast growth factor in the supernatant from UC‑MSCs was higher compared with that from DP‑MSCs (P<0.05). However, UC‑MSC supernatants exhibited lower levels of of keratinocyte growth factor, vascular endothelial growth factor and stem cell factor compared with DP‑MSCs (P<0.05). In conclusion, in vitro characterization of MSCs from these tissue sources revealed a number of common biological properties. However, the results also demonstrated clear biological distinctions and suggested that UC‑MSCs may have more effective application prospects.

Mesenchymal stem cells and cell-derived extracellular vesicles protect hippocampal neurons from oxidative stress and synapse damage induced by amyloid-β oligomers

Alzheimer's disease (AD) is a disabling and highly prevalent neurodegenerative condition, for which there are no effective therapies. Soluble oligomers of the amyloid-β peptide (AβOs) are thought to be proximal neurotoxins involved in early neuronal oxidative stress and synapse damage, ultimately leading to neurodegeneration and memory impairment in AD. The aim of the current study was to evaluate the neuroprotective potential of mesenchymal stem cells (MSCs) against the deleterious impact of AβOs on hippocampal neurons. To this end, we established transwell cocultures of rat hippocampal neurons and MSCs. We show that MSCs and MSC-derived extracellular vesicles protect neurons against AβO-induced oxidative stress and synapse damage, revealed by loss of pre- and postsynaptic markers. Protection by MSCs entails three complementary mechanisms: 1) internalization and degradation of AβOs; 2) release of extracellular vesicles containing active catalase; and 3) selective secretion of interleukin-6, interleukin-10, and vascular endothelial growth factor to the medium. Results support the notion that MSCs may represent a promising alternative for cell-based therapies in AD.

Overexpression of LOXIN Protects Endothelial Progenitor Cells From Apoptosis Induced by Oxidized Low Density Lipoprotein

Human endothelial progenitor cells (hEPC) are adult stem cells located in the bone marrow and peripheral blood. Studies have indicated that hEPC play an important role in the recovery and repair of injured endothelium, however, their quantity and functional capacity is reduced in several diseases including hypercholesterolemia. Recently, it has been demonstrated that hEPC express lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and its activation by oxidized low-density lipoprotein (ox-LDL) induces cellular dysfunction and apoptosis. This study aimed to investigate whether overexpression of LOXIN, a truncated isoform of LOX-1 that acts as a dominant negative, plays a protective role against ox-LDL-induced apoptosis in hEPC. Human endothelial progenitor cells exposed to ox-LDL showed a significant increase in LOX-1 expression, and apoptosis began at ox-LDL concentrations above 50 μg/mL. All hEPC apoptosed at 200 μg/mL ox-LDL. High LOXIN expression was generated using adenoviral systems in hEPC and SiHa cells transduced with 100 colony-forming units per cell. Transduced LOXIN localized to the plasma membrane and blocked ox-LDL uptake mediated by LOX-1. Overexpression of LOXIN protected hEPC from ox-LDL-induced apoptosis, and therefore maybe a novel way of improving hEPC function and quantity. These results suggest that adenoviral vectors of LOXIN may provide a possible treatment for diseases related to ox-LDL and vascular endothelium dysfunction, including atherosclerosis.

Matrix metalloproteinases regulate extracellular levels of SDF-1/CXCL12, IL-6 and VEGF in hydrogen peroxide-stimulated human periodontal ligament fibroblasts

Periodontitis is a highly prevalent infectious disease characterized by the progressive inflammatory destruction of tooth-supporting structures, leading to tooth loss. The underling molecular mechanisms of the disease are incompletely understood, precluding the development of more efficient screening, diagnostic and therapeutic approaches. We investigated the interrelation of three known effector mechanisms of the cellular response to periodontal infection, namely reactive oxygen species (ROS), matrix metalloproteinases (MMPs) and cytokines in primary cell cultures of human periodontal ligament fibroblast (hPDLF). We demonstrated that ROS increase the activity/levels of gelatinolytic MMPs, and stimulate cytokine secretion in hPDLF. Additionally, we proved that MMPs possesses immune modulatory capacity, regulating the secreted levels of cytokines in ROS-stimulated hPDLF cultures. This evidence provides further insight in the molecular pathogenesis of periodontitis, contributing to the future development of more effective therapies.