(D-151) Endothelial Glycocalyx-Dependent Expression of Endothelin-1

Introduction:: Endothelin-1 (ET-1) plays a significant role in many cardiovascular-related conditions such as hypertension, and atherosclerosis. ET-1 is produced by endothelial cells (EC) and secreted into the extracellular space to bind to either endothelial B receptor (ETB) on EC or the endothelial A receptor on smooth muscle cells. Reports suggest that the expression of ET-1 is shear stress magnitude and time-dependent and that the disruption of cytoskeletal structures could mediate the shear stress-induced production of ET-1. The endothelial glycocalyx (GCX) which is a mechanotransducer and is located in close proximity to ETB and is also firmly rooted in the EC membrane through its core proteins could co-participate in the release of ETI during disease. We hypothesize that the GCX heparan sulfate (HS) is involved in the regulation of ETB on the surface of EC and the production of ET-1 in a shear stress-dependent manner

Materials and Methods:: With the use of immunofluorescence staining, enzymes that target specific GCX components and a customized microfluidic technology that mimics the vascular microenviroment, we defined the role of shear forces and the GCX in the expression of ET-1 and its receptor ETB on the surface of human lung microvascular endothelial cells

Results, Conclusions, and Discussions:: Results

We found that the shear-dependent increase in the expression of GCX component heparan sulfate resulted in a significant increase in the expression of ETB and a significant decrease in the expression of ET-1. We also discovered that enzyme-induced removal of GCX heparan sulfate resulted in the significant decrease in expression of ETB and a significant increase in the release of ET-1.



Conclusion

We discovered that vasculo-protective shear stress results in a robust GCX which supports the structural integrity of ETB in a way that maintains the ETB-ET-1-axis. Vasculo-protective shear stress also decreases the production and release of ET-1 into the vascular microenvironment there by potentially limiting unnecessary vasomotion which has implication for diseases such as hypertension and atherosclerosis.



Discussion

These results confirm that GCX HS could co-participate with ETB to release ET-1, in an alternative GCX-mediated pathway for modulating the expression of ET-1 during disease. These results also points to the fact that restoring GCX during cardiovascular-related diseases could minimize the release of ET-1


Acknowledgements (Optional): : I will like to thank Worcester Polytechnic Institute for the startup funds to support this work. I will also like to thank the imaging core facility at WPI fro support with imaging, special thanks to Victoria Bicchieri.

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