Advantages and Challenges of Cardiovascular and Lymphatic Studies in Zebrafish Research

Since its introduction, the zebrafish has provided an important reference system to model and study cardiovascular development as well as lymphangiogenesis in vertebrates. A scientific workshop, held at the 2018 European Zebrafish Principal Investigators Meeting in Trento (Italy) and chaired by Massimo Santoro, focused on the most recent methods and studies on cardiac, vascular and lymphatic development. Daniela Panáková and Natascia Tiso described new molecular mechanisms and signaling pathways involved in cardiac differentiation and disease. Arndt Siekmann and Wiebke Herzog discussed novel roles for Wnt and VEGF signaling in brain angiogenesis. In addition, Brant Weinstein’s lab presented data concerning the discovery of endothelium-derived macrophage-like perivascular cells in the zebrafish brain, while Monica Beltrame’s studies refined the role of Sox transcription factors in vascular and lymphatic development. In this article, we will summarize the details of these recent discoveries in support of the overall value of the zebrafish model system not only to study normal development, but also associated disease states

Organ-specific lymphatic vasculature: From development to pathophysiology.

Recent discoveries of novel functions and diverse origins of lymphatic vessels have drastically changed our view of lymphatic vasculature. Traditionally regarded as passive conduits for fluid and immune cells, lymphatic vessels now emerge as active, tissue-specific players in major physiological and pathophysiological processes. Lymphatic vessels show remarkable plasticity and heterogeneity, reflecting their functional specialization to control the tissue microenvironment. Moreover, alternative developmental origins of lymphatic endothelial cells in some organs may contribute to the diversity of their functions in adult tissues. This review aims to summarize the most recent findings of organotypic differentiation of lymphatic endothelial cells in terms of their distinct (patho)physiological functions in skin, lymph nodes, small intestine, brain, and eye. We discuss recent advances in our understanding of the heterogeneity of lymphatic vessels with respect to the organ-specific functional and molecular specialization of lymphatic endothelium, such as the hybrid blood-lymphatic identity of Schlemm's canal, functions of intestinal lymphatics in dietary fat uptake, and discovery of meningeal lymphatic vasculature and perivascular brain lymphatic endothelial cells

Consensus guidelines for the use and interpretation of angiogenesis assays

The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference

Doctor of Philosophy

dissertationEmbryological development encompasses a fascinating collection of biological events somehow able to act jointly and precisely to give as a final product a welldeveloped viable organism, which can span from very basic to extremely complex animals. Understanding how individual cells can talk to their neighbors and establish their peculiar fates in a time- and space-dependent manner has intrigued the developmental biology field for ages. Signals among cells in a developing embryo are responsible for establishing such fates in a synchronized mode and this process is achieved mostly by strict feedbacks between cell-signaling pathways such Wnt, Fgf, Notch, BMP and Chemokines among others. I present a study on the functions of Heparan Sulfate Proteoglycans (HSPGs) during the zebrafish lateral line development. The lateral line is an excellent model to perform these studies as we have detailed knowledge on the signaling pathways involved in its development. HSPGs are extracellular glycoproteins with powerful, yet poorly understood, signaling modulating properties. I use the lateral line to dissect the regulation by HSPGs mainly on Wnt/β-catenin and Fgf signaling, two essential pathways during this developmental process. My data demonstrate that HSPGs are not only modulators but also target genes of the Wnt/β-catenin and Fgf signaling feedback. Furthermore, they are essential for Fgf signal transduction, migration and cell polarity. Also, I analyzed for the first time the role of a specific HSPG, glypican4, in lateral line development and iv discerned that this gene affects primordium migration non-cell-autonomously by inducing the formation of the muscles along the horizontal myoseptum, and controlling the proper orientation of the hair cells in the lateral line sensory organs, called neuromasts

Heparan Sulfate Proteoglycans Regulate Fgf Signaling and Cell Polarity during Collective Cell Migration

SummaryCollective cell migration is a highly regulated morphogenetic movement during embryonic development and cancer invasion that involves the precise orchestration and integration of cell-autonomous mechanisms and environmental signals. Coordinated lateral line primordium migration is controlled by the regulation of chemokine receptors via compartmentalized Wnt/β-catenin and fibroblast growth factor (Fgf) signaling. Analysis of mutations in two exostosin glycosyltransferase genes (extl3 and ext2) revealed that loss of heparan sulfate (HS) chains results in a failure of collective cell migration due to enhanced Fgf ligand diffusion and loss of Fgf signal transduction. Consequently, Wnt/β-catenin signaling is activated ectopically, resulting in the subsequent loss of the chemokine receptor cxcr7b. Disruption of HS proteoglycan (HSPG) function induces extensive, random filopodia formation, demonstrating that HSPGs are involved in maintaining cell polarity in collectively migrating cells. The HSPGs themselves are regulated by the Wnt/β-catenin and Fgf pathways and thus are integral components of the regulatory network that coordinates collective cell migration with organ specification and morphogenesis