The Study On Biological Characteristics Of Human Umbilical Vein Endothelial Cells Under Shear Stress

In the21st Centry, the study on biogenesis and development of and microRNAhas been hot spots in life science. Nowadays, atherosclerosis is at the top list ofcardiovascular diseases, and has become the primary factor leading to death. But nowmost cardiovascular diseases genesis and development studies base on endothelialcells genome, signaling passway and biological characteristics level, the effect ofdifferent mechanical stimulus model (eg. Blood sheat stress) and microRNA on thebiogenesis and development of atherosclerosis is still in the starting phase.ECs are a layer of continuous pinacocyte which cover the whole surface of bloodvessels. Since they directly contact with blood flow, they subject blood shear stresscontinuely. ECs have the ability to feel mechanical forces changes in the blood flow,which regulates the function of vascular ECs and smooth muscle cells by activing thecorresponding signaling pathways to modulate. MicroRNAs (miRs) are shortnoncoding17–27nucleotide RNAs that negatively regulate the expression of targetgenes at the posttranscriptional level. The function of miR in HUVEC proliferation,aptosis and other aspects has become more and more important at present, but themechanism of the shear-induced miR still need further study.For further investigation of the biological characteristics of EC under shear stress,in this study, we used human umbilical cord endothelial cells (HUVECs) as object,which isolated from human umbilical cord; applied blood laminar shear stimulus onHUVEC in vitro, and studied the signal passway, gene regulation and biologicalcharacteristics, especially on the shear-regulation microRNA expression; focused onthe relationship of signal passway and miceroRNA in endothelial cells under shear.Our recent studies by using microRNA microarrary showed that there were22shear-regulation microRNAs in HUVEC, among them,9can be upregulated,13can bedownregulated. In this study we chose miR-19a,23b and27b as object, led to themodulation of EC proliferation, cell cycle change, focused on the miR expressionchange after shear-related signaling pathways were blocked by chemical inhibitors.The results we demonstrated the inhibition of PI3K pathway attenuated the shear-induced miR-19a, and the inhibition of MAPK pathway attenuated miR-23b,27b.The knockdown of miR-19a using antagomir-19a oligonucleotide (AM19a) decreasedthe shear-induced PI3K activation; whereas AM-23b,27b reduced the shear-inducedMAPK activation. Furthermore, the overexpression of miR-19a overrides thesuppressive effects of PI3K inhibitors on shear-induced PI3K activation; theoverexpression of miR-23b,27b had similar effects on MAPK activations. Our findingssuggest a positive feedback loop that PI3K and MAPK mediate shear regulation ofmiRs expression, which in turn modulate the shear-regulated PI3K/MAPK signalingevents in ECs.In conclusion, this study clearfied in the biological characteristics changes inHUVEC when subjected to the shear stress. We first mentioned there are feedbackloops exsit in PI3K-miR-19a, and MAPK-miR-23b/27b. The results of the studyprovides a theoretical basis to explore the effect of signal pathway and microRNApathway in HUVEC under shear condition, also provides sufficient experimentalevidence for better study of the biogenesis and development mechanism ofcardiovascular disease and medicine development.