Project description:Using multicolor lineage tracing, in vivo time-lapse imaging and single cell transcriptional profiling in a mouse glioma model, we identify tumour blood endothelial cells carrying a Csf1r lineage trace. These Csf1r lineage endothelial cells (CLECs) form up to 10% of the tumour vasculature and express endothelial cell markers as well as a unique set of genes that can also be found in single cell transcriptome data of tumour endothelium from various human tumours.
Project description:Invasion of lymphatic vessels is a key step in the metastasis of primary tumour cells to draining lymph nodes. Recent evidence indicates that such metastasis can be facilitated by tumour lymphangiogenesis, although it remains unclear whether this is a consequence of increased lymphatic vessel numbers or alteration in the properties of the vessels themselves. Here we have addressed this important question by comparing the RNA profile of normal dermal lymphatic endothelial cells (LEC) with those isolated from tumours of murine T-241/VEGF-C metastatic fibrosarcoma. Our findings reveal significant changes in the expression of some 792 genes in tumour lymphatics (â?¥ 2 fold up/downregulation, p â?¤ 0.05), involving particularly transcripts associated with junctional adhesion, immunomodulation, extracellular matrix and vessel growth/patterning, several of which we have confirmed by RT-PCR and/or immunohistochemistry. Interestingly, this altered phenotype could not be attributed solely to VEGF-C induced lymphoproliferation, as no similar change in gene expression was reported when human LEC were cultured with VEGF-C in vitro. Moreover, we show that a key protein upregulated in the mouse model, namely the tight junction protein Endothelial Cell Specific Adhesion Molecule (ESAM), is similarly upregulated in tumour lymphatic vessels from 2/2 patients with head and neck squamous cell carcinoma and 4/4 patients with aggressive bladder carcinoma. These findings demonstrate a previously unrecognized influence of tumour environment on lymphatic gene expression and identify candidate tumour specific vessel markers that may prove valuable for either prognosis or therapy. Experiment Overall Design: Here we have investigated the invasion of lymphatic vessels as a key step in the metastasis of primary tumour cells to draining lymph nodes by comparing the gene expression profile of normal dermal lymphatic endothelial cells (LEC) with those isolated from tumours of murine T241/VEGF-C/GFP metastatic fibrosarcoma. Three biological replicates were analyzed from each group.
Project description:Invasion of lymphatic vessels is a key step in the metastasis of primary tumour cells to draining lymph nodes. Recent evidence indicates that such metastasis can be facilitated by tumour lymphangiogenesis, although it remains unclear whether this is a consequence of increased lymphatic vessel numbers or alteration in the properties of the vessels themselves. Here we have addressed this important question by comparing the RNA profile of normal dermal lymphatic endothelial cells (LEC) with those isolated from tumours of murine T-241/VEGF-C metastatic fibrosarcoma. Our findings reveal significant changes in the expression of some 792 genes in tumour lymphatics (≥ 2 fold up/downregulation, p ≤ 0.05), involving particularly transcripts associated with junctional adhesion, immunomodulation, extracellular matrix and vessel growth/patterning, several of which we have confirmed by RT-PCR and/or immunohistochemistry. Interestingly, this altered phenotype could not be attributed solely to VEGF-C induced lymphoproliferation, as no similar change in gene expression was reported when human LEC were cultured with VEGF-C in vitro. Moreover, we show that a key protein upregulated in the mouse model, namely the tight junction protein Endothelial Cell Specific Adhesion Molecule (ESAM), is similarly upregulated in tumour lymphatic vessels from 2/2 patients with head and neck squamous cell carcinoma and 4/4 patients with aggressive bladder carcinoma. These findings demonstrate a previously unrecognized influence of tumour environment on lymphatic gene expression and identify candidate tumour specific vessel markers that may prove valuable for either prognosis or therapy. Keywords: Tumor, Metastasis, Lymphatic endothelium, comparative transcriptional profiling
Project description:We did three sets of microarrays with three replicates each for a total of 9 arrays. Each array was run using pooled RNA from three animals. The three conditions were Normal tail skin (no intervention), Lymphedema tail skin(due to surgical lymphatic vessel blockage), and Surgical Sham control tail skin(surgical incision with no lymphatic vessel blockage). 15ug of test and reference (e17.5 mouse whole embryo) RNA was used for labeling.
Project description:Tissue lymphatic vessels network plays critical roles in immune surveillance and tissue homeostasis in response to pathogen invasion, but how lymphatic system per se is remolded during infection is less understood. Here, we observed that influenza infection induces a significant increase of lymphatic vessel numbers in the lung, accompanied with extensive proliferation of lymphatic endothelial cells (LECs). Single-cell RNA sequencing illustrated the heterogeneity of LECs, identifying a novel PD-L1+ subpopulation that is present during viral infection but not at steady state. Specific deletion of Pd-l1 in LECs elevated the expansion of lymphatic vessel numbers during viral infection. Together these findings elucidate a dramatic expansion of lung lymphatic network in response to viral infection, and reveal a PD-L1+ LEC subpopulation that potentially modulates lymphatic vessel remolding.
Project description:Complex lymphatic anomalies (CLAs) are sporadically occurring diseases caused by the maldevelopment of lymphatic vessels. We and others recently reported that somatic activating mutations in KRAS can cause CLAs. However, the mechanisms by which activating KRAS mutations cause CLAs are poorly understood. Here we show that KRASG12D expression in lymphatic endothelial cells (LECs) during embryonic development impairs the formation of lymphovenous valves and causes the enlargement of lymphatic vessels. We demonstrate that KRASG12D expression in primary human LECs induces cell spindling, proliferation, and migration. It also increases AKT and ERK1/2 phosphorylation and decreases the expression of genes that regulate lymphatic vessel maturation. We show that MEK1/2 inhibition with the FDA-approved drug trametinib suppresses KRASG12D-induced morphological changes, proliferation, and migration. Trametinib also decreases ERK1/2 phosphorylation and increases the expression of genes that regulate the maturation of lymphatic vessels. We also show that trametinib and Cre-mediated expression of a dominant-negative form of MEK1 (Map2k1K97M) suppresses KRASG12D-induced lymphatic vessel hyperplasia in embryos. Last, we demonstrate that conditional knockout of wild-type Kras in LECs does not affect the formation or function of lymphatic vessels. Together, our data indicate that KRAS/MAPK signaling must be tightly regulated during embryonic development for the proper development of lymphatic vessels and further support the testing of MEK1/2 inhibitors for treating CLAs.
Project description:Kaposi sarcoma is the most common cancer in AIDS patients and is typified by red skin lesions. The disease is caused by the KSHV virus (HHV8) and is recognisable by its distinctive red skin lesions. The lesions are KSHV-infected spindle cells, most commonly the lymphatic endothelial and blood vessel endothelial cells (LEC and BEC), plus surrounding stroma. The effects of KSHV infection of both LEC and BEC were assayed using Affymetrix hgu133plus2 chips at 72 hours post infection.
Project description:To identify genes regulating the functional specification of collecting lymphatic vessels, we performed transcriptome profiling of dermal ECs isolated from adult mouse ear skin by flow cytometry.
Project description:Proliferation and migration of lymphatic endothelial cells (LECs) are essential for lymphatic vessel growth (also known as lymphangiogenesis), which plays a critical role in regulating the tissue fluid balance and immune cell trafficking in physiological and pathological conditions.