Single cell RNA-sequencing of Tumor-Associated High Endothelial Cells (TA-HECs) and comparison to their counterparts in homeostatic and inflamed mouse lymph nodes

ABSTRACT: High endothelial venules (HEVs) are specialized postcapillary venules that mediate lymphocyte trafficking from the blood into lymph nodes. HEV-like blood vessels are found in solid tumors in association with CD8+ T cell infiltration.This study uses single cell RNA-sequencing using the Fluidigm C1 system as a method to evaluate the transcriptome in lymph node and tumor-associated HEV endothelial cells (LN-HECs and TA-HECs). We isolated MECA-79+ TA-HECs and CD31+MECA-79- tumor-associated endothelial cells (TA-ECs) by cell sorting and we compared their transcriptome to those of their counterparts in homeostatic (LN-HECs and LN-ECs) or inflamed (iLN-HECs) lymph nodes. TA-HECs express high levels of endothelial cell markers Cdh5 and Pecam1 (CD31), post-capillary venule marker Ackr1 (DARC) and venous transcription factor Nr2f2, indicating that they correspond to post-capillary venule endothelium, like their lymph node counterparts. The genes encoding HEV sialomucins decorated by the sulfated MECA-79 epitope (CD34 and Emcn, endomucin) and the core 1 branching enzyme B3gnt3 that is essential for its biosynthesis, are equally expressed in all HEC populations, whereas sulfotransferases Chst2 and Chst4 are expressed at lower levels in TA-HECs. Although TA-HECs are molecularly distinct from lymph node HECs, they share several important characteristics with iLN-HECs, including the upregulation of endothelial selectins (Selp, Sele) and inflammatory chemokines CXCL9 and CXCL10, the ligands for chemokine receptor CXCR3 on effector T cells. Finally, endothelial cell adhesion molecules ICAM1, ICAM2 and VCAM1 that are important for lymphocyte sticking to HEVs, are expressed at similar levels in all HECs. Together, these findings indicated that MECA-79+ TA-HECs, similar to HECs in immune-stimulated lymph nodes, exhibit an inflamed phenotype characterized by co-expression of MECA-79+ antigens with endothelial selectins and inflammatory chemokines.

ORGANISM(S): Mus musculus

PROVIDER: GSE154898 | GEO | 2021/12/14

REPOSITORIES: GEO