TY - JOUR A1 - Liu, Fengming A1 - Han, Kun A1 - Blair, Robert A1 - Kenst, Kornelia A1 - Qin, Zhongnan A1 - Upcin, Berin A1 - Wörsdörfer, Philipp A1 - Midkiff, Cecily C. A1 - Mudd, Joseph A1 - Belyaeva, Elizaveta A1 - Milligan, Nicholas S. A1 - Rorison, Tyler D. A1 - Wagner, Nicole A1 - Bodem, Jochen A1 - Dölken, Lars A1 - Aktas, Bertal H. A1 - Vander Heide, Richard S. A1 - Yin, Xiao-Ming A1 - Kolls, Jay K. A1 - Roy, Chad J. A1 - Rappaport, Jay A1 - Ergün, Süleyman A1 - Qin, Xuebin T1 - SARS-CoV-2 Infects Endothelial Cells In Vivo and In Vitro JF - Frontiers in Cellular and Infection Microbiology N2 - SARS-CoV-2 infection can cause fatal inflammatory lung pathology, including thrombosis and increased pulmonary vascular permeability leading to edema and hemorrhage. In addition to the lung, cytokine storm-induced inflammatory cascade also affects other organs. SARS-CoV-2 infection-related vascular inflammation is characterized by endotheliopathy in the lung and other organs. Whether SARS-CoV-2 causes endotheliopathy by directly infecting endothelial cells is not known and is the focus of the present study. We observed 1) the co-localization of SARS-CoV-2 with the endothelial cell marker CD31 in the lungs of SARS-CoV-2-infected mice expressing hACE2 in the lung by intranasal delivery of adenovirus 5-hACE2 (Ad5-hACE2 mice) and non-human primates at both the protein and RNA levels, and 2) SARS-CoV-2 proteins in endothelial cells by immunogold labeling and electron microscopic analysis. We also detected the co-localization of SARS-CoV-2 with CD31 in autopsied lung tissue obtained from patients who died from severe COVID-19. Comparative analysis of RNA sequencing data of the lungs of infected Ad5-hACE2 and Ad5-empty (control) mice revealed upregulated KRAS signaling pathway, a well-known pathway for cellular activation and dysfunction. Further, we showed that SARS-CoV-2 directly infects mature mouse aortic endothelial cells (AoECs) that were activated by performing an aortic sprouting assay prior to exposure to SARS-CoV-2. This was demonstrated by co-localization of SARS-CoV-2 and CD34 by immunostaining and detection of viral particles in electron microscopic studies. Moreover, the activated AoECs became positive for ACE-2 but not quiescent AoECs. Together, our results indicate that in addition to pneumocytes, SARS-CoV-2 also directly infects mature vascular endothelial cells in vivo and ex vivo, which may contribute to cardiovascular complications in SARS-CoV-2 infection, including multipleorgan failure. KW - endothelial cell infection KW - animal models KW - SARS-CoV-2 KW - aorta ring KW - hACE2 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-241948 SN - 2235-2988 VL - 11 ER - TY - JOUR A1 - Upcin, Berin A1 - Henke, Erik A1 - Kleefeldt, Florian A1 - Hoffmann, Helene A1 - Rosenwald, Andreas A1 - Irmak-Sav, Ster A1 - Aktas, Huseyin Bertal A1 - Rückschloß, Uwe A1 - Ergün, Süleyman T1 - Contribution of adventitia-derived stem and progenitor cells to new vessel formation in tumors JF - Cells N2 - Blocking tumor vascularization has not yet come to fruition to the extent it was hoped for, as angiogenesis inhibitors have shown only partial success in the clinic. We hypothesized that under- appreciated vascular wall-resident stem and progenitor cells (VW-SPCs) might be involved in tumor vascularization and influence effectiveness of anti-angiogenic therapy. Indeed, in patient samples, we observed that vascular adventitia-resident CD34\(^+\) VW-SPCs are recruited to tumors in situ from co-opted vessels. To elucidate this in detail, we established an ex vivo model using concomitant embedding of multi-cellular tumor spheroids (MCTS) and mouse aortic rings (ARs) into collagen gels, similar to the so-called aortic ring assay (ARA). Moreover, ARA was modified by removing the ARs’ adventitia that harbors VW-SPCs. Thus, this model enabled distinguishing the contribution of VW-SPCs from that of mature endothelial cells (ECs) to new vessel formation. Our results show that the formation of capillary-like sprouts is considerably delayed, and their number and network formation were significantly reduced by removing the adventitia. Substituting iPSC-derived neural spheroids for MCTS resulted in distinct sprouting patterns that were also strongly influenced by the presence or absence of VW-SPCs, also underlying the involvement of these cells in non-pathological vascularization. Our data suggest that more comprehensive approaches are needed in order to block all of the mechanisms contributing to tumor vascularization. KW - vascularization model KW - tumor spheroids KW - vascular wall stem and progenitor cells KW - aortic adventitia KW - vasculogenesis KW - tumor-vessel wall-interface model Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-242577 VL - 10 IS - 7 ER - TY - JOUR A1 - Wagner, Nicole A1 - Mott, Kristina A1 - Upcin, Berin A1 - Stegner, David A1 - Schulze, Harald A1 - Ergün, Süleyman T1 - CXCL12-abundant reticular (CAR) cells direct megakaryocyte protrusions across the bone marrow sinusoid wall JF - Cells N2 - Megakaryocytes (MKs) release platelets into the lumen of bone marrow (BM) sinusoids while remaining to reside within the BM. The morphogenetic events of this complex process are still not fully understood. We combined confocal laser scanning microscopy with transmission and serial block-face scanning electron microscopy followed by 3D-reconstruction on mouse BM tissue sections. These analyses revealed that MKs in close vicinity to BM sinusoid (BMS) wall first induce the lateral retraction of CXCL12-abundant reticular (CAR) cells (CAR), followed by basal lamina (BL) degradation enabling direct MK-sinusoidal endothelial cells (SECs) interaction. Subsequently, an endothelial engulfment starts that contains a large MK protrusion. Then, MK protrusions penetrate the SEC, transmigrate into the BMS lumen and form proplatelets that are in direct contact to the SEC surface. Furthermore, such processes are induced on several sites, as observed by 3D reconstructions. Our data demonstrate that MKs in interaction with CAR-cells actively induce BMS wall alterations, including CAR-cell retraction, BL degradation, and SEC engulfment containing a large MK protrusion. This results in SEC penetration enabling the migration of MK protrusion into the BMS lumen where proplatelets that are adherent to the luminal SEC surface are formed and contribute to platelet release into the blood circulation. KW - megakaryocytes KW - microvasculature KW - CXCL12-abundant reticular (CAR)-cells Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-234180 SN - 2073-4409 VL - 10 IS - 4 ER -