Title : The Secretome of Activated ECs
Abstract :
- HUVECs were stimulated with PMA, a commonly used secretagogue that induces exocytosis of endothelial vesicles
- As previously reported (26), the morphology of ECs changes from spindle-shaped to round upon PMA activation, and the rod-shaped Weibel-Palade bodies, unique storage vesicles within ECs containing vWF and many other secreted proteins , fuse with the cell membrane (Fig. 1A)
- In total, the secretomes of 17 primary ECs were analyzed via gel-LC-MS/MS, with or without deglycosylation
- Apart from 123 secreted proteins , the conditioned medium of PMA-stimulated ECs was particularly rich in surface antigens and receptors , including many established endothelial markers (Table I)
- All identified proteins and peptides are listed in supplemental Tables S1 and S2, respectively
- The distribution of the frequencies and the cumulated distribution of the number of samples in which proteins were identified are shown in supplemental Fig
- S1
- MS datasets of three biological replicates have been deposited in PRIDE (accession numbers 26908–27003)
- Immunoblots confirmed that proteins such as fibronectin and biglycan were constitutively secreted (Fig. 1B)
- Others such as agrin and lymphatic vessel endothelial hyaluronic acid receptor 1 were released upon PMA stimulation, providing an explanation for why previously unidentified proteins (8, 10) were found in the present analysis (Fig. 1C)
- An overlay between secreted (Cy3 and Cy 5; green and red color) and cellular (Cy 2; blue color) proteins is shown in Fig. 1D
- Common spots were numbered (supplemental Fig
- S2) and identified via LC-MS/MS (supplemental Table S3)
- Certain proteins , such as von Willebrand antigen 2 (a propeptide of vWF , AA 23–763), were clearly more abundant in the secretome of PMA-treated HUVECs
Output (sent_index, trigger,
protein,
sugar,
site):
Output(Part-Of) (sent_index,
protein,
site):
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):