Project description:Formation and maturation of a functional blood vascular system is required for the development and maintenance of all tissues in the body. During the process of blood vessel development, primordial endothelial cells are formed and become specified toward arterial or venous fates to generate a circulatory network that provides nutrients and oxygen to, and removes metabolic waste from, all tissues. Specification of arterial and venous endothelial cells occurs in conjunction with suppression of endothelial cell cycle progression, and endothelial cell hyperproliferation is associated with potentially lethal arterial-venous malformations. However, the mechanistic role that cell cycle state plays in arterial-venous specification is unknown. Herein, studying vascular development in Cdh5-CreERT2;R26FUCCI2aR reporter mice, we find that venous and arterial endothelial cells exhibit a propensity for different cell cycle states during development and in adulthood. That is, venous endothelial cells are predominantly FUCCI-Negative, while arterial endothelial cells are enriched for the FUCCI-Red reporter. Single cell RNA sequencing analysis of developing retinal endothelial cells reveals that venous endothelial cells are enriched for the FUCCI-Negative state and BMP signaling, while arterial endothelial cells are enriched for the FUCCI-Red state and TGF-b signaling. Further transcriptional analyses and live imaging of cultured endothelial cells expressing the FUCCI reporter show that reporter-negative corresponds to an early G1 state and reporter-red corresponds to late G1 state. We find the early G1 state is essential for BMP4-induced venous gene expression, whereas late G1 state is essential for TGF-b1-induced arterial gene expression. In a mouse model of endothelial cell hyperproliferation and disrupted arterial-venous specification, pharmacological inhibition of endothelial cell cycle prevents the vascular defects. Collectively, our results show that endothelial cell cycle control plays a key role in arterial-venous network formation, and distinct cell cycle states provide distinct windows of opportunity for the molecular induction of arterial vs. venous specification.
Project description:Formation and maturation of a functional blood vascular system is required for the development and maintenance of all tissues in the body. During the process of blood vessel development, primordial endothelial cells are formed and become specified toward arterial or venous fates to generate a circulatory network that provides nutrients and oxygen to, and removes metabolic waste from, all tissues. Specification of arterial and venous endothelial cells occurs in conjunction with suppression of endothelial cell cycle progression, and endothelial cell hyperproliferation is associated with potentially lethal arterial-venous malformations. However, the mechanistic role that cell cycle state plays in arterial-venous specification is unknown. Herein, studying vascular development in Cdh5-CreERT2;R26FUCCI2aR reporter mice, we find that venous and arterial endothelial cells exhibit a propensity for different cell cycle states during development and in adulthood. That is, venous endothelial cells are predominantly FUCCI-Negative, while arterial endothelial cells are enriched for the FUCCI-Red reporter. Single cell RNA sequencing analysis of developing retinal endothelial cells reveals that venous endothelial cells are enriched for the FUCCI-Negative state and BMP signaling, while arterial endothelial cells are enriched for the FUCCI-Red state and TGF-b signaling. Further transcriptional analyses and live imaging of cultured endothelial cells expressing the FUCCI reporter show that reporter-negative corresponds to an early G1 state and reporter-red corresponds to late G1 state. We find the early G1 state is essential for BMP4-induced venous gene expression, whereas late G1 state is essential for TGF-b1-induced arterial gene expression. In a mouse model of endothelial cell hyperproliferation and disrupted arterial-venous specification, pharmacological inhibition of endothelial cell cycle prevents the vascular defects. Collectively, our results show that endothelial cell cycle control plays a key role in arterial-venous network formation, and distinct cell cycle states provide distinct windows of opportunity for the molecular induction of arterial vs. venous specification.
Project description:We previously identified differentially expressed miRNAs between arterial and venous blood in rats; however, whether immune cell composition and transcriptional states differ along the arterial–venous axis remains unclear. Here, single-cell RNA sequencing of 119,481 PBMCs, complemented by flow cytometry and protein-level validation, were performed to characterize immune heterogeneity between arterial and venous blood. Cell composition analysis showed enrichment of T cells in arterial blood, whereas B cells, NK cells, and monocytes were more abundant in venous blood. At the subset level, naïve T cells were enriched in arterial blood, while CD8⁺ effector memory T cells were increased in venous blood. NK cell analysis demonstrated enrichment of cytotoxic NK subsets in venous blood and resting NK subsets in arterial blood, whereas monocyte subset proportions were comparable between compartments. Transcriptomic analysis revealed reduced JAK–STAT signaling in venous PBMCs, consistent with decreased STAT3 and NF-κB phosphorylation. Subset-specific analysis further showed reduced TNF/NF-κB signaling and enrichment of ribosome-associated pathways in venous T cells, enhanced cytotoxic, chemokine, and NF-κB–related programs in venous NK cells, and attenuated TNF/NF-κB signaling with increased ribosome-associated activity in monocytes, indicating functional reprogramming without compositional changes. Collectively, these findings demonstrate coordinated but cell type–specific immune adaptations along the arterial–venous axis, identifying blood sampling site as a critical determinant of immune readouts and a previously underappreciated source of variability in immunological studies.
Project description:Circulating microRNAs (miRNAs) presented in venous plasma have recently been demonstrated as powerful biomarkers for the diagnosis and prognostic prediction of complex diseases like cancer. Nevertheless, those presented in arterial plasma have been ignored based on the assumption that the miRNA profiles in arterial and venous plasma would be identical. Here, we disputed this intuitive assumption by comparing arterial and venous plasma miRNA expression profiles from male rats using microarray technique. Though the microRNA profiles were largely similar, a considerable number of miRNAs showed significant differential expression, including 10 arterial highly expressed miRNAs and 14 venous highly expressed miRNAs. The differentially expressed miRNAs were validated by qRT-PCR. We performed computational analysis of the function enrichment and disease association of these miRNAs and their targets. Our analysis also suggested significant correlations between plasma miRNA expression and tissue miRNA expression. Four arterial highly expressed miRNAs showed enriched expression in specific tissues and thus could serve as novel biomarker candidates.
Project description:The vascular tree has considerable diversity, with discrete regions having different physiologic characteristics and permeability. Of note are venules that are significantly more sensitive to pro-inflammatory cytokines than arterioles. We used microarrays to identify molecular signatures that distinguish primary human venous endothelial cells from arterial endothelial cells. We used microarrays to identify genes differentially expressed by venous vs arterial human endothelial cells.
Project description:The cellular evolutions and molecular programs underlying the arteriovenous fate settling of embryonic vascular endothelial cells (ECs) are critical for understanding arteriogenesis and inspiring new approaches for regenerative biology. Using different strategies of single-cell RNA sequencing, we constructed the transcriptional landscape of early arteriovenous EC development in both mouse and human embryos, demonstrating the evolutionary conservation of principal vascular EC types and providing a series of conserved arteriovenous genes. We showed an unexpected diversity of arteriovenous characteristics in morphologically alike vascular plexus and further uncovered two transcriptomically distinct arterial EC types, whereas most of heterologous ligand-receptor pairs were shared by different arterial vasculatures. By computational predicting and further genetic lineage tracing, we revealed the widespread venous arterialization in the mid-gestational mouse embryo proper. Interestingly, we demonstrated at transcriptomic level that Notch1 was dispensable for venous arterialization but required subsequently for the arterial feature strengthening in the arterial plexus ECs. Altogether, our findings unprecedentedly detail the comprehensive single-cell mapping of early embryonic vascular ECs in vivo, decipher an asymmetric arteriovenous characteristics different than that in adults, and reveal an extensive venous-to-arterial fate conversion in the vascular plexus.
Project description:Arterial-venous specification of endothelial cells during vascular development requires coordination between intracellular signaling, cell cycle state, and transcription factor activity. However, the intrinsic regulatory mechanisms that govern these processes are poorly understood. To investigate this, we assessed endothelial chromatin accessibility during vascular development. Murine postnatal day (P)6 and P15 retinal endothelial cells were analyzed by single cell Assay for Transposase Accessible Chromatin (ATAC) sequencing, revealing heterogeneous accessibility of chromatin across an arterial-venous continuum. Enhancer regulatory network analysis predicted transcription factors with high activity, including Sox17. Transcription factors with differential arterial-venous activity showed dual activator and repressor functions, with many regulated by cell cycle-dependent chromatin accessibility. We validated SOX17 function in human endothelial cells, identifying that SOX17 inhibits proliferation and promotes arterial gene expression. Our findings suggest that dual roles of key endothelial transcription factors are regulated by chromatin accessibility in a cell cycle- and subtype-specific manner to control arterial-venous specification.
Project description:Arterial-venous specification of endothelial cells during vascular development requires coordination between intracellular signaling, cell cycle state, and transcription factor activity. However, the intrinsic regulatory mechanisms that govern these processes are poorly understood. To investigate this, we assessed endothelial chromatin accessibility during vascular development. Murine postnatal day (P)6 and P15 retinal endothelial cells were analyzed by single cell Assay for Transposase Accessible Chromatin (ATAC) sequencing, revealing heterogeneous accessibility of chromatin across an arterial-venous continuum. Enhancer regulatory network analysis predicted transcription factors with high activity, including Sox17. Transcription factors with differential arterial-venous activity showed dual activator and repressor functions, with many regulated by cell cycle-dependent chromatin accessibility. We validated SOX17 function in human endothelial cells, identifying that SOX17 inhibits proliferation and promotes arterial gene expression. Our findings suggest that dual roles of key endothelial transcription factors are regulated by chromatin accessibility in a cell cycle- and subtype-specific manner to control arterial-venous specification.
Project description:Arterial-venous specification of endothelial cells during vascular development requires coordination between intracellular signaling, cell cycle state, and transcription factor activity. However, the intrinsic regulatory mechanisms that govern these processes are poorly understood. To investigate this, we assessed endothelial chromatin accessibility during vascular development. Murine postnatal day (P)6 and P15 retinal endothelial cells were analyzed by single cell Assay for Transposase Accessible Chromatin (ATAC) sequencing, revealing heterogeneous accessibility of chromatin across an arterial-venous continuum. Enhancer regulatory network analysis predicted transcription factors with high activity, including Sox17. Transcription factors with differential arterial-venous activity showed dual activator and repressor functions, with many regulated by cell cycle-dependent chromatin accessibility. We validated SOX17 function in human endothelial cells, identifying that SOX17 inhibits proliferation and promotes arterial gene expression. Our findings suggest that dual roles of key endothelial transcription factors are regulated by chromatin accessibility in a cell cycle- and subtype-specific manner to control arterial-venous specification.
Project description:Arterial-venous specification of endothelial cells during vascular development requires coordination between intracellular signaling, cell cycle state, and transcription factor activity. However, the intrinsic regulatory mechanisms that govern these processes are poorly understood. To investigate this, we assessed endothelial chromatin accessibility during vascular development. Murine postnatal day (P)6 and P15 retinal endothelial cells were analyzed by single cell Assay for Transposase Accessible Chromatin (ATAC) sequencing, revealing heterogeneous accessibility of chromatin across an arterial-venous continuum. Enhancer regulatory network analysis predicted transcription factors with high activity, including Sox17. Transcription factors with differential arterial-venous activity showed dual activator and repressor functions, with many regulated by cell cycle-dependent chromatin accessibility. We validated SOX17 function in human endothelial cells, identifying that SOX17 inhibits proliferation and promotes arterial gene expression. Our findings suggest that dual roles of key endothelial transcription factors are regulated by chromatin accessibility in a cell cycle- and subtype-specific manner to control arterial-venous specification.