scholarly journals Live Imaging of Intracranial Lymphatics in the Zebrafish

2021 ◽  
Vol 128 (1) ◽  
pp. 42-58 ◽  
Author(s):  
Daniel Castranova ◽  
Bakary Samasa ◽  
Marina Venero Galanternik ◽  
Hyun Min Jung ◽  
Van N. Pham ◽  
...  

Rationale: The recent discovery of meningeal lymphatics in mammals is reshaping our understanding of fluid homeostasis and cellular waste management in the brain, but visualization and experimental analysis of these vessels is challenging in mammals. Although the optical clarity and experimental advantages of zebrafish have made this an essential model organism for studying lymphatic development, the existence of meningeal lymphatics has not yet been reported in this species. Objective: Examine the intracranial space of larval, juvenile, and adult zebrafish to determine whether and where intracranial lymphatic vessels are present. Methods and Results: Using high-resolution optical imaging of the meninges in living animals, we show that zebrafish possess a meningeal lymphatic network comparable to that found in mammals. We confirm that this network is separate from the blood vascular network and that it drains interstitial fluid from the brain. We document the developmental origins and growth of these vessels into a distinct network separated from the external lymphatics. Finally, we show that these vessels contain immune cells and perform live imaging of immune cell trafficking and transmigration in meningeal lymphatics. Conclusions: This discovery establishes the zebrafish as a important new model for experimental analysis of meningeal lymphatic development and opens up new avenues for probing meningeal lymphatic function in health and disease.

Author(s):  
Daniel Castranova ◽  
Bakary Samasa ◽  
Marina Venero Galanternik ◽  
Hyun Min Jung ◽  
Van N. Pham ◽  
...  

ABSTRACTRationaleThe recent discovery of meningeal lymphatics in mammals is reshaping our understanding of fluid homeostasis and cellular waste management in the brain, but visualization and experimental analysis of these vessels is challenging in mammals. Although the optical clarity and experimental advantages of zebrafish have made this an essential model organism for studying lymphatic development, the existence of meningeal lymphatics has not yet been reported in this species.ObjectiveExamine the intracranial space of larval, juvenile, and adult zebrafish to determine whether and where intracranial lymphatic vessels are present.Methods and ResultsUsing high-resolution optical imaging of the meninges in living animals, we show that zebrafish possess a meningeal lymphatic network comparable to that found in mammals. We confirm that this network is separate from the blood vascular network and that it drains interstitial fluid from the brain. We document the developmental origins and growth of these vessels into a distinct network separated from the external lymphatics. Finally we show that these vessels contain immune cells and perform live imaging of immune cell trafficking and transmigration in meningeal lymphatics.ConclusionsThis discovery establishes the zebrafish as a important new model for experimental analysis of meningeal lymphatic development, and opens up new avenues for probing meningeal lymphatic function in health and disease.


Angiogenesis ◽  
2021 ◽  
Author(s):  
Daniyal J. Jafree ◽  
David A. Long ◽  
Peter J. Scambler ◽  
Christiana Ruhrberg

AbstractLymphatic vessels have critical roles in both health and disease and their study is a rapidly evolving area of vascular biology. The consensus on how the first lymphatic vessels arise in the developing embryo has recently shifted. Originally, they were thought to solely derive by sprouting from veins. Since then, several studies have uncovered novel cellular mechanisms and a diversity of contributing cell lineages in the formation of organ lymphatic vasculature. Here, we review the key mechanisms and cell lineages contributing to lymphatic development, discuss the advantages and limitations of experimental techniques used for their study and highlight remaining knowledge gaps that require urgent attention. Emerging technologies should accelerate our understanding of how lymphatic vessels develop normally and how they contribute to disease.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0249256
Author(s):  
Esther Redder ◽  
Nils Kirschnick ◽  
Stefanie Bobe ◽  
René Hägerling ◽  
Nils Rouven Hansmeier ◽  
...  

Lymphatic vessels are indispensable for tissue fluid homeostasis, transport of solutes and dietary lipids and immune cell trafficking. In contrast to blood vessels, which are easily visible by their erythrocyte cargo, lymphatic vessels are not readily detected in the tissue context. Their invisibility interferes with the analysis of the three-dimensional lymph vessel structure in large tissue volumes and hampers dynamic intravital studies on lymphatic function and pathofunction. An approach to overcome these limitations are mouse models, which express transgenic fluorescent proteins under the control of tissue-specific promotor elements. We introduce here the BAC-transgenic mouse reporter strain Vegfr3-tdTomato that expresses a membrane-tagged version of tdTomato under control of Flt4 regulatory elements. Vegfr3-tdTomato mice inherited the reporter in a mendelian fashion and showed selective and stable fluorescence in the lymphatic vessels of multiple organs tested, including lung, kidney, heart, diaphragm, intestine, mesentery, liver and dermis. In this model, tdTomato expression was sufficient for direct visualisation of lymphatic vessels by epifluorescence microscopy. Furthermore, lymph vessels were readily visualized using a number of microscopic modalities including confocal laser scanning, light sheet fluorescence and two-photon microscopy. Due to the early onset of VEGFR-3 expression in venous embryonic vessels and the short maturation time of tdTomato, this reporter offers an interesting alternative to Prox1-promoter driven lymphatic reporter mice for instance to study the developmental differentiation of venous to lymphatic endothelial cells.


2019 ◽  
Author(s):  
Hyun Min Jung ◽  
Ciara Hu ◽  
Alexandra M. Fister ◽  
Andrew E. Davis ◽  
Daniel Castranova ◽  
...  

ABSTRACTThe post-transcriptional mechanisms contributing to molecular regulation of developmental lymphangiogenesis and lymphatic network assembly are not well understood. Here, we use high throughput small RNA sequencing to identify miR-204, a highly conserved miRNA dramatically enriched in lymphatic vs. blood endothelial cells, and we demonstrate that this miRNA plays a critical role during lymphatic development. Suppressing miR-204 leads to loss of lymphatic vessel formation, while overproducing miR-204 in lymphatic vessels accelerates lymphatic vessel formation, suggesting a positive role during developmental lymphangiogenesis. We also identify the NFATC1 transcription factor as a key conserved target for post-transcriptional regulation by miR-204 during lymphangiogenesis. While miR-204 suppression leads to loss of lymphatics, knocking down its target NFATC1 leads to lymphatic hyperplasia, and the loss of lymphatics in miR-204-deficient animals can be rescued by NFATC1 knockdown. Together, our results highlight a miR-204/NFATC1 molecular regulatory axis required for proper lymphatic development.


Author(s):  
Michael Weiler ◽  
J. Brandon Dixon

The lymphatic vasculature is present in nearly every tissue of the body to serve essential functions in fluid homeostasis, immune cell trafficking, and lipid transport, and it has been implicated in the progression of several diseases. Despite the critical roles that this system performs, very little is known about the lymphatic vasculature in comparison to the blood vasculature, which can be attributed, in part, to the difficulty associated with imaging lymphatic vessels. With the growing interest in studying lymphatics, near-infrared (NIR) imaging has emerged in the literature as a novel lymphatic imaging modality to simultaneously improve spatial resolution to visualize small initial lymphatics and increase temporal resolution to capture the dynamic lymphatic pump function responsible for fluid propulsion.


2017 ◽  
Vol 38 (4) ◽  
pp. 669-686 ◽  
Author(s):  
Melanie-Jane Hannocks ◽  
Michelle E Pizzo ◽  
Jula Huppert ◽  
Tushar Deshpande ◽  
N Joan Abbott ◽  
...  

Perivascular compartments surrounding central nervous system (CNS) vessels have been proposed to serve key roles in facilitating cerebrospinal fluid flow into the brain, CNS waste transfer, and immune cell trafficking. Traditionally, these compartments were identified by electron microscopy with limited molecular characterization. Using cellular markers and knowledge on cellular sources of basement membrane laminins, we here describe molecularly distinct compartments surrounding different vessel types and provide a comprehensive characterization of the arachnoid and pial compartments and their connection to CNS vessels and perivascular pathways. We show that differential expression of plectin, E-cadherin and laminins α1, α2, and α5 distinguishes pial and arachnoid layers at the brain surface, while endothelial and smooth muscle laminins α4 and α5 and smooth muscle actin differentiate between arterioles and venules. Tracer studies reveal that interconnected perivascular compartments exist from arterioles through to veins, potentially providing a route for fluid flow as well as the transport of large and small molecules.


Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1344
Author(s):  
Kim Pin Yeo ◽  
Hwee Ying Lim ◽  
Veronique Angeli

In recent years, lymphatic vessels have received increasing attention and our understanding of their development and functional roles in health and diseases has greatly improved. It has become clear that lymphatic vessels are critically involved in acute and chronic inflammation and its resolution by supporting the transport of immune cells, fluid, and macromolecules. As we will discuss in this review, the involvement of lymphatic vessels has been uncovered in atherosclerosis, a chronic inflammatory disease of medium- and large-sized arteries causing deadly cardiovascular complications worldwide. The progression of atherosclerosis is associated with morphological and functional alterations in lymphatic vessels draining the diseased artery. These defects in the lymphatic vasculature impact the inflammatory response in atherosclerosis by affecting immune cell trafficking, lymphoid neogenesis, and clearance of macromolecules in the arterial wall. Based on these new findings, we propose that targeting lymphatic function could be considered in conjunction with existing drugs as a treatment option for atherosclerosis.


2021 ◽  
Vol 8 ◽  
Author(s):  
Takuro Miyazaki ◽  
Akira Miyazaki

Lymphatic vessels are necessary for maintaining tissue fluid balance, trafficking of immune cells, and transport of dietary lipids. Growing evidence suggest that lymphatic functions are limited under hypercholesterolemic conditions, which is closely related to atherosclerotic development involving the coronary and other large arteries. Indeed, ablation of lymphatic systems by Chy-mutation as well as depletion of lymphangiogenic factors, including vascular endothelial growth factor-C and -D, in mice perturbs lipoprotein composition to augment hypercholesterolemia. Several investigations have reported that periarterial microlymphatics were attracted by atheroma-derived lymphangiogenic factors, which facilitated lymphatic invasion into the intima of atherosclerotic lesions, thereby modifying immune cell trafficking. In contrast to the lipomodulatory and immunomodulatory roles of the lymphatic systems, the critical drivers of lymphangiogenesis and the details of lymphatic insults under hypercholesterolemic conditions have not been fully elucidated. Interestingly, cholesterol-lowering trials enable hypercholesterolemic prevention of lymphatic drainage in mice; however, a causal relationship between hypercholesterolemia and lymphatic defects remains elusive. In this review, the contribution of aberrant lymphangiogenesis and lymphatic cholesterol transport to hypercholesterolemic atherosclerosis was highlighted. The causal relationship between hypercholesterolemia and lymphatic insults as well as the current achievements in the field were discussed.


Development ◽  
2021 ◽  
Vol 148 (11) ◽  
Author(s):  
Mathias Francois ◽  
Anna Oszmiana ◽  
Natasha L. Harvey

ABSTRACT The lymphatic vasculature is an integral component of the cardiovascular system. It is essential to maintain tissue fluid homeostasis, direct immune cell trafficking and absorb dietary lipids from the digestive tract. Major advances in our understanding of the genetic and cellular events important for constructing the lymphatic vasculature during development have recently been made. These include the identification of novel sources of lymphatic endothelial progenitor cells, the recognition of lymphatic endothelial cell specialisation and heterogeneity, and discovery of novel genes and signalling pathways underpinning developmental lymphangiogenesis. Here, we review these advances and discuss how they inform our understanding of lymphatic network formation, function and dysfunction.


2019 ◽  
Author(s):  
Daniel Peña-Jimenez ◽  
Silvia Fontenete ◽  
Diego Megias ◽  
Coral Fustero-Torre ◽  
Osvaldo Graña-Castro ◽  
...  

AbstractLymphatic vessels (LV) are essential for skin fluid homeostasis and immune cell trafficking, but whether LV are associated with hair follicle (HF) regeneration is not known. Here, by using steady and live imaging approaches in mouse skin, we show that lymphatic capillaries distribute to the anterior permanent region of individual HF and interconnect neighboring HF at the level of the HF bulge, in a hair follicle stem cell (HFSC)-dependent manner. LV further connect individual HF in triads and dynamically flow across the skin. Interestingly, at the onset of the physiological HFSC activation, or upon pharmacological or genetic induction of HF growth, LV transiently expand their caliber suggesting an increased tissue drainage capacity. Interestingly, the physiological LV caliber increase is associated with a distinct gene expression correlated to ECM and cytoskeletal reorganization. Using mouse genetics, we show that the depletion of LV blocks the pharmacological induction of HF growth. Our findings define LV as components of the HFSC niche, coordinating HF connections at tissue-level, and provide insight into their functional contribution to HF regeneration.


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