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:Fluid clearance mediated by lymphatic vessels is known to be essential for lung inflation and gas exchange function during the transition from prenatal to postnatal life, yet the molecular mechanisms that regulate lymphatic function remain unclear. Here, we profiled the molecular features of lymphatic endothelial cells (LECs) in embryonic and postnatal day (P) 0 lungs by single-cell RNA-seq analysis. We identified that the expression of c-JUN is transiently upregulated in P0 LECs. Conditional knockout of Jun in LECs impairs the opening of lung lymphatic vessels at birth, leading to fluid retention in the lungs and neonatal death. We further demonstrated that increased mechanical pressure induces the expression of c-JUN in LECs. c-JUN regulates the opening of lymphatic vessels by modulating remodeling of the actin cytoskeleton in LECs. Our study established the essential regulatory function of c-JUN-mediated transcriptional responses in facilitating lung lymphatic fluid clearance at birth.
Project description:Fluid clearance mediated by lymphatic vessels is known to be essential for lung inflation and gas exchange function during the transition from prenatal to postnatal life, yet the molecular mechanisms that regulate lymphatic function remain unclear. Here, we profiled the molecular features of lymphatic endothelial cells (LECs) in embryonic and postnatal day (P) 0 lungs by single-cell RNA-seq analysis. We identified that the expression of c-JUN is transiently upregulated in P0 LECs. Conditional knockout of Jun in LECs impairs the opening of lung lymphatic vessels at birth, leading to fluid retention in the lungs and neonatal death. We further demonstrated that increased mechanical pressure induces the expression of c-JUN in LECs. c-JUN regulates the opening of lymphatic vessels by modulating remodeling of the actin cytoskeleton in LECs. Our study established the essential regulatory function of c-JUN-mediated transcriptional responses in facilitating lung lymphatic fluid clearance at birth.
Project description:Fluid clearance mediated by lymphatic vessels is known to be essential for lung inflation and gas exchange function during the transition from prenatal to postnatal life, yet the molecular mechanisms that regulate lymphatic function remain unclear. Here, we profiled the molecular features of lymphatic endothelial cells (LECs) in embryonic and postnatal day (P) 0 lungs by single-cell RNA-seq analysis. We identified that the expression of c-JUN is transiently upregulated in P0 LECs. Conditional knockout of Jun in LECs impairs the opening of lung lymphatic vessels at birth, leading to fluid retention in the lungs and neonatal death. We further demonstrated that increased mechanical pressure induces the expression of c-JUN in LECs. c-JUN regulates the opening of lymphatic vessels by modulating remodeling of the actin cytoskeleton in LECs. Our study established the essential regulatory function of c-JUN-mediated transcriptional responses in facilitating lung lymphatic fluid clearance at birth.
Project description:GeneChip® Mouse Gene 2.0 ST Array for C57BL/6 mouse skin dermal primary lymphatic endothelial cells (Ms LEC) and mouse lymphatic endothelial cell line SVEC4-10 GeneChip® Human Gene 2.0 ST Array for human primary lymphatic endothelial cells (Hu LEC) Total RNA from lymphatic cell line SVEC4-10 were used for GeneChip® Mouse Gene 2.0 ST Array. SVEC4-10 samples, human and mouse LEC samples.
Project description:GeneChip® Mouse Gene 2.0 ST Array for C57BL/6 mouse skin dermal primary lymphatic endothelial cells (Ms LEC) and mouse lymphatic endothelial cell line SVEC4-10 GeneChip® Human Gene 2.0 ST Array for human primary lymphatic endothelial cells (Hu LEC) Total RNA from lymphatic cell line SVEC4-10 were used for GeneChip® Mouse Gene 2.0 ST Array.
Project description:The lymphatic vasculature regulates lung homeostasis through drainage of fluid and trafficking of immune cells and plays a key role in the response to lung injury in several disease states. We have previously shown that lymphatic dysfunction occurs early in the pathogenesis of chronic obstructive pulmonary disease (COPD) caused by cigarette smoke (CS) and that this is associated with increased thrombin and fibrin clots in lung lymph. However, the direct effects of CS and thrombin on lymphatic endothelial cells (LECs) in COPD are not entirely clear. Studies of the blood vasculature have shown that COPD is associated with increased thrombin, which causes endothelial dysfunction after CS exposure and is characterized by changes in the expression of coagulation factors and leukocyte adhesion proteins. Here, we determined whether similar changes occur in LECs. We used an in vitro cell culture system and treated human lung microvascular lymphatic endothelial cells with cigarette smoke extract (CSE) and/or thrombin. We found that CSE treatment led to decreased fibrinolytic activity in LECs, which was associated with increased expression of plasminogen activator inhibitor 1 (PAI-1). LECs treated with both CSE and thrombin together had a decreased expression of TFPI and an increased expression of vascular adhesion molecules. RNA sequencing of lung LECs isolated from mice exposed to CS also showed upregulation of prothrombotic and inflammatory pathways at both acute and chronic exposure time points. Analysis of publicly available single-cell RNA sequencing of LECs as well as immunohistochemical staining of lung tissue from COPD patients supported these data and showed an increased expression of inflammatory markers in LECs from COPD patients compared to those from controls. These studies suggest that in parallel with blood vessels, the lymphatic endothelium undergoes inflammatory changes associated with CS exposure and increased thrombin in COPD. Further research is needed to unravel the mechanisms by which these changes affect lymphatic function and drive tissue injury in COPD.