Abstract TP265: Microparticles Play A Role In Mediating Angiogenic Effect Of Mesenchymal Stromal Cells On Cerebral Vascular Endothelial Cells
Microparticles (MPs) represent a novel network for intercellular communication. Our previous works found that MPs from db/db diabetic mice impaired endothelial progenitor cell function. This study investigated the role of MPs from mesenchymal stromal cells (MSCs) in regulating cerebrovascular endothelial cell (cEC) function and gene expression. Male C57BL/6 mice and green fluorescent protein (GFP)-transgenic mice were used for cEC and MSC donors, respectively. The cECs were cultured on 6-well plates and MSCs were seeded on well inserts with a 0.4 μm pore sized filter for co-culture for 3 days before various measurements. MSC conditional medium (MSC-CM) was used for producing MPs and MSC-CM deprived of MPs (MSC-CM-dMP) by centrifuge. MPs deprived of mRNAs and miRNAs (MSC-MP-dRNA) were prepared by treating with RNAse. In some experiments, cECs were incubated with normal culture medium (control), MSC-CM, MSC-CM-dMP, MSC-MPs or MSC-MP-dRNA for 3 days. After different treatments, the cECs were used for confocal microscopy analysis of GFP level, real-time PCR analysis of angiogenic gene expression and functional analyses. The levels of angiogenic factors were measured by ELISA method. Results showed: 1) GFP-MPs were appeared in cEC culture medium, and GFP was detected in cECs after co-culture with MSCs; 2) Co-culture with MSCs or culture with MSC-CM significantly upregulated mRNA expression of VEGFR2 and CXCR4 in cECs and increased the angiogenic factors (VEGF and SDF-1) in culture supernatant; 3) Co-culture with MSCs or culture with MSC-CM increased cEC function (migration: 68.6 ± 3.2, 66.8 ± 2.6 and 48.8 ± 2.6 tubes/field for MSC, MSC-CM and control, respectively; tube formation: 52.8 ± 2.6, 48.8 ± 2.0 and 32.6 ± 1.2 tubes/field for MSC, MSC-CM and control, respectively; n=5/group, P<0.05 or 0.01, vs. control); 4) Whereas, incubation with MSC-CM-dMP or MSC-MP-dRNA aborted the effect on mRNA expression, and reduced the functional effects by about 50%. In conclusion, MPs mediate angiogenic effect of MSCs on cECs via RNA and/or protein deliveries, which represent a novel mechanism of cell communication, providing a potential therapeutic target for endothelial dysfunction and cerebrovascular diseases.
- © 2012 by American Heart Association, Inc.