The molecular mechanism of Semaphorin 3E-Plexin-D1 signaling in shaping vascular topology during development
Final Report Abstract
In this project, we have used computational modeling predictions, mouse genetics mosaic analysis, live imaging of individual cell dynamics in actively forming blood vessel networks and computational quantification of branching points to elucidate how Sema3E-Plexin-D1 signaling can modify vascular density by impinging on the central pattern generator VEGF/Notch signaling. This work shows that the lack of Sema3E-Plexin-D1 signaling slows down the rate of tip cell selection, resulting in a less branched vascular network. These results suggest that temporal regulation of this critical, iterative aspect of network formation could be a general mechanism, and additional temporal regulators with varying pace (fast vs. slow) may exist to sculpt vascular topology in different tissues. Furthermore, our findings provide novel insights into our understanding of morphogenesis in general, and aid in efforts to develop therapeutic approaches for tissue engineering and control of tumor progression and vascular diseases. However, we had underestimated the work and time it took to optimize the live imaging assay. The most problematic aspect of the project was to find the best imaging conditions for the live imaging experiments. Here, I tested several microscopes available in the numerous imaging facilities of Harvard Medical School and the neighboring research institutions. Due to the growth of the embedded specimen during the imaging process, the imaging position had to be constantly monitored during the scan. This meant checking the imaging setup every 3-4 hours over a course of 15-20 hours. Therefore, the live imaging experiments, which were a crucial part of the project took significantly longer than expected.
Publications
- Semaphorin 3E-Plexin D1 signaling regulates the dynamics of tip and stalk cells. Angiogenesis Gordon Research Conference 2013 Aug 04-09, Salve Regina University, Rhode Island, USA
Kur E, Kim J, Bentley K, Oh WJ, Gu C
- Temporal modulation of collective cell behavior controls vascular network topology. eLife. 2016 Feb 24;5. pii: e13212
Kur E, Kim J, Tata A, Comin CH, Harrington KI, Costa LD, Bentley K, Gu C
(See online at https://doi.org/10.7554/eLife.13212.001)
