| First Author | Ren B | Year | 2022 |
| Journal | Elife | Volume | 11 |
| PubMed ID | 35511221 | Mgi Jnum | J:338730 |
| Mgi Id | MGI:7275981 | Doi | 10.7554/eLife.69219 |
| Citation | Ren B, et al. (2022) Endothelial SIRPalpha signaling controls VE-cadherin endocytosis for thymic homing of progenitor cells. Elife 11:e69219 |
| abstractText | Thymic homing of hematopoietic progenitor cells (HPCs) is tightly regulated for proper T cell development. Previously we have identified a subset of specialized thymic portal endothelial cells (TPECs), which is important for thymic HPC homing. However, the underlying molecular mechanism still remains unknown. Here, we found that signal regulatory protein alpha (SIRPalpha) is preferentially expressed on TPECs. Disruption of CD47-SIRPalpha signaling in mice resulted in reduced number of thymic early T cell progenitors (ETPs), impaired thymic HPC homing, and altered early development of thymocytes. Mechanistically, Sirpa-deficient ECs and Cd47-deficient bone marrow progenitor cells or T lymphocytes demonstrated impaired transendothelial migration (TEM). Specifically, SIRPalpha intracellular ITIM motif-initiated downstream signaling in ECs was found to be required for TEM in an SHP2- and Src-dependent manner. Furthermore, CD47 signaling from migrating cells and SIRPalpha intracellular signaling were found to be required for VE-cadherin endocytosis in ECs. Thus, our study reveals a novel role of endothelial SIRPalpha signaling for thymic HPC homing for T cell development. |
