On the evolution of cnidarian eyes

Cnidarians and their medusa stage are generally considered to be diploblasts and therefore ancestral to Bilaterians. They represent the most primitive phylum where striated muscle tissue, a complex system of nerve rings and different sense organs of high complexity, including eyes have evolved in the jellyfish stage. We demonstrated that jellyfish and the triploblast Bilateria use homologous gene cascades and developmental pathways to build these muscle systems. The expression of JellyD, a derived jellyfish homolog of the master regulator of muscle tissue MyoD, is correlated with that of bilaterian muscle determination factors. Furthermore, the eye determination genes of the Pax and Six families of cnidarians have bilaterian-like expression patterns. Although no bona fide Pax6 homolog could be found, it can be shown that among the four Pax genes characterized, cnidarians do have a Pax gene (PaxA-Cr) that is exclusively expressed in the maintenance and regeneration of eye tissue. Additionally the hypothesis of a loss of Pax genes within the cnidarians can be rebut as well as the claim that cubozoans would possess only one Pax gene. Cladonema jellyfish have three cognate members of the sine oculis/Six class family of which Six1/2-Cr and Six3/6-Cr are upregulated during eye regeneration. Analysis of gene expression patterns during eye regeneration shows that the cnidarian Pax gene is upregulated before the Six genes, indicating a possible upstream position in the gene regulatory network. The results are in agreement with monophyly of eye evolution and indicate that the common ancestor between Cnidaria and Bilateria had a more complex anatomy than commonly anticipated

Whole-Body Regeneration

This Open Access volume provides a comprehensive overview of the latest tools available to scientists to study the many facets of whole-body regeneration (WBR). The chapters in this book are organized into six parts. Part One provides a historical overview on the study of the WBR phenomena focusing on the primary challenges of this research. Parts Two and Three explore a series of non-vertebrate zoological contexts that provide experimental models for WBR, showing how they can be approached with cellular tools. Parts Four, Five, and Six discuss the future advancements of WBR, reporting about the cutting-edge techniques in genetics and omics used to dissect the underlying mechanisms of WBR, and systems biology approaches to reach a synthetic view of WBR. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and thorough, Whole-Body Regeneration: Methods and Protocols is a valuable resource for scientists and researchers who want to learn more about this important and developing field

Whole-Body Regeneration

This Open Access volume provides a comprehensive overview of the latest tools available to scientists to study the many facets of whole-body regeneration (WBR). The chapters in this book are organized into six parts. Part One provides a historical overview on the study of the WBR phenomena focusing on the primary challenges of this research. Parts Two and Three explore a series of non-vertebrate zoological contexts that provide experimental models for WBR, showing how they can be approached with cellular tools. Parts Four, Five, and Six discuss the future advancements of WBR, reporting about the cutting-edge techniques in genetics and omics used to dissect the underlying mechanisms of WBR, and systems biology approaches to reach a synthetic view of WBR. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and thorough, Whole-Body Regeneration: Methods and Protocols is a valuable resource for scientists and researchers who want to learn more about this important and developing field

Advances in Aquatic Invertebrate Stem Cell Research

This publication is based upon work from COST Action ’16203 MARISTEM Stem cells of marine/aquatic invertebrates: from basic research to innovative applications’, supported by COST (European Cooperation in Science and Technology). COST (European Cooperation in Science and Technology) is a funding agency for research and innovation networks. Our Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation. Aquatic invertebrates represent the largest biodiversity and the widest phylogenetic radiation on Earth, with more than 2 million known species. Up until a few years ago, their use as model organisms in biological research was limited by the paucity of omics data. Recently, the situation has rapidly changed and is still changing. Today, the genomes and various transcriptomes of many aquatic invertebrate species, as well as many recombinant proteins of invertebrate origin, are available. New technologies have revolutionized the available toolbox of research methodologies. This explains the rising interest of researchers in the use of aquatic invertebrates as reliable model organisms. In contrast to the prevalence of diverse oligopotent and unipotent stem cells in vertebrates, aquatic invertebrates (especially non-ecdysozoan invertebrates) exhibit multiple adult cell types with stem cell attributes characterized by multipotency and pluripotency; furthermore, these give rise to cell lineages characteristic of more than a single germ layer, sometimes with somatic and germ line potentials. In addition, unlike vertebrates, aquatic invertebrate adult stem cells are disseminated and widespread inside the animal body, are not associated with a regulatory microenvironment (niche) and do participate in aging and regeneration phenomena. These properties can help us to better understand the processes and phenomena in mammalian stem cell biology, such as natural chimerism and cancer, aging and senescence, immunity and autoimmune responses, which are all difficult to explain or understand in the human context. The COST Action 16203 MARISTEM "Stem cells of marine/aquatic invertebrates: from basic research to innovative applications" started in 2017 with the aim to foster the knowledge of the biology of aquatic invertebrates stem cells and strengthen the European community of researchers on aquatic invertebrate stem cells in order to build innovative ideas relevant to various biomedical disciplines. This book represents one of the deliverables of the Action and collects part of the materials produced during the past 3 years within the network as a tool to disseminate and render available what has been achieved up to now. We hope that this book will be useful to scientists interested in stem cells of non-model organisms, with particular reference to aquatic invertebrate

Advances in Aquatic Invertebrate Stem Cell Research

This publication is based upon work from COST Action ’16203 MARISTEM Stem cells of marine/aquatic invertebrates: from basic research to innovative applications’, supported by COST (European Cooperation in Science and Technology).COST (European Cooperation in Science and Technology) is a funding agency for research and innovation networks. Our Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation.www.cost.eu Aquatic invertebrates represent the largest biodiversity and the widest phylogenetic radiation on Earth, with more than 2 million known species. Up until a few years ago, their use as model organisms in biological research was limited by the paucity of omics data. Recently, the situation has rapidly changed and is still changing. Today, the genomes and various transcriptomes of many aquatic invertebrate species, as well as many recombinant proteins of invertebrate origin, are available. New technologies have revolutionized the available toolbox of research methodologies. This explains the rising interest of researchers in the use of aquatic invertebrates as reliable model organisms.In contrast to the prevalence of diverse oligopotent and unipotent stem cells in vertebrates, aquatic invertebrates (especially non-ecdysozoan invertebrates) exhibit multiple adult cell types with stem cellattributes characterized by multipotency and pluripotency; furthermore, these give rise to cell lineages characteristic of more than a single germ layer, sometimes with somatic and germ line potentials. In addition, unlike vertebrates, aquatic invertebrate adult stem cells are disseminated and widespread inside the animal body, are not associated with a regulatory microenvironment (niche) and do participate in aging and regeneration phenomena. These properties can help us to better understand the processes and phenomena in mammalian stem cell biology, such as natural chimerism and cancer, aging and senescence, immunity and autoimmune responses, which are all difficult to explain or understand in the human context.The COST Action 16203 MARISTEM "Stem cells of marine/aquatic invertebrates: from basic research to innovative applications" started in 2017 with the aim to foster the knowledge of the biology of aquatic invertebrates stem cells and strengthen the European community of researchers on aquatic invertebrate stem cells in order to build innovative ideas relevant to various biomedical disciplines. This book represents one of the deliverables of the Action and collects part of the materials produced during the past 3 years within the network as a tool to disseminate and render available what has been achieved up to now. We hope that this book will be useful to scientists interested in stem cells of non-model organisms, with particular reference to aquatic invertebrates

Advances in Aquatic Invertebrate Stem Cell Research

This publication is based upon work from COST Action ’16203 MARISTEM Stem cells of marine/aquatic invertebrates: from basic research to innovative applications’, supported by COST (European Cooperation in Science and Technology). COST (European Cooperation in Science and Technology) is a funding agency for research and innovation networks. Our Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation. Aquatic invertebrates represent the largest biodiversity and the widest phylogenetic radiation on Earth, with more than 2 million known species. Up until a few years ago, their use as model organisms in biological research was limited by the paucity of omics data. Recently, the situation has rapidly changed and is still changing. Today, the genomes and various transcriptomes of many aquatic invertebrate species, as well as many recombinant proteins of invertebrate origin, are available. New technologies have revolutionized the available toolbox of research methodologies. This explains the rising interest of researchers in the use of aquatic invertebrates as reliable model organisms. In contrast to the prevalence of diverse oligopotent and unipotent stem cells in vertebrates, aquatic invertebrates (especially non-ecdysozoan invertebrates) exhibit multiple adult cell types with stem cell attributes characterized by multipotency and pluripotency; furthermore, these give rise to cell lineages characteristic of more than a single germ layer, sometimes with somatic and germ line potentials. In addition, unlike vertebrates, aquatic invertebrate adult stem cells are disseminated and widespread inside the animal body, are not associated with a regulatory microenvironment (niche) and do participate in aging and regeneration phenomena. These properties can help us to better understand the processes and phenomena in mammalian stem cell biology, such as natural chimerism and cancer, aging and senescence, immunity and autoimmune responses, which are all difficult to explain or understand in the human context. The COST Action 16203 MARISTEM "Stem cells of marine/aquatic invertebrates: from basic research to innovative applications" started in 2017 with the aim to foster the knowledge of the biology of aquatic invertebrates stem cells and strengthen the European community of researchers on aquatic invertebrate stem cells in order to build innovative ideas relevant to various biomedical disciplines. This book represents one of the deliverables of the Action and collects part of the materials produced during the past 3 years within the network as a tool to disseminate and render available what has been achieved up to now. We hope that this book will be useful to scientists interested in stem cells of non-model organisms, with particular reference to aquatic invertebrate

Wnt signalling and peroxisome dynamics in the zebrafish (Danio rerio)

Cell-cell or paracrine signalling is a form of cellular communication in which a cell produces a signal that influences the behaviour of neighbouring cells, which is important because it allows for the local coordination of the activities of groups of cells. This coordination is indispensable during development; for example, paracrine Wnt signalling is fundamental to body patterning in all metazoans where it helps to determine cell fate in a developing embryo. Wnt can regulate the transcription of target genes including cyclin and peroxisome-proliferator activated receptor-ẟ. The importance of Wnt signalling is not temporally limited, and Wnt has roles throughout the life of an organism such as the management of stem cells and the cellular abundance of mitochondria, the ‘sister organelle’ of the peroxisome. The peroxisome is a single membrane-bound organelle with diverse roles in healthy development and life, inclusive of the breakdown of very long chain fatty acids (VLCFAs) and the production of plasmalogens for efficient nervous conduction. The relationship between the Wnt signalling pathway and peroxisomes is unknown. Here I investigate the influence of Wnt signalling on peroxisome dynamics in zebrafish. To do so, canonical wnt8a was knocked out and knocked down using the genomic engineering tool CRISPR and Morpholino oligomers. The number and morphology of peroxisomes was observed in Wnt8a-deficient zebrafish embryos and appeared to be aggregated and less numerate than in wild type zebrafish. Consistently, in zebrafish embryos overexpressing wnt8a, peroxisomes were visualised as highly numerate singular puncta. I hypothesise that - in addition to a set of functions in development and tissue homeostasis - Wnt signalling has a novel role in regulating peroxisome proliferation in zebrafish

FGF signaling and cell state transitions during organogenesis

Organogenesis is a complex choreography of morphogenetic processes, patterns and dynamic shape changes as well as the specification of cell fates. Although several molecular actors and context-specific mechanisms have already been identified, our general understanding of the fundamental principles that govern the formation of organs is far from comprehensive. The application of the concept of ‘rebuild it to understand it’ from synthetic biology represents a promising alternative to the classical approach of ‘break it to understand it’ in order to distill biological understanding from complex developmental processes. According to this ‘rebuilding’ concept, in this study we sought to develop an experimental approach to induce the formation of organs from progenitor cells ‘on demand’ and to investigate the minimum requirements for such a process. The zebrafish lateral line chain cells are a powerful in vivo model for our study because they are a group of naïve multipotent progenitor cells that display mesenchyme-like features. In order to bring these cells to form organs, we used the well-known role of the FGF signaling pathway as a driver of organogenesis in the lateral line and developed an inducible and constitutively active form of the fibroblast growth factor receptor 1a (chemoFGFR). The cell-autonomous induction of this chemoFGFR in chain cells effectively triggered the formation of fully mature organs and thus enabled spatial and temporal control of the organogenesis process. Next, we asked what it takes to form an organ de novo. We used a combination of real-time microscopy, single cell tracking, polarity quantification, and mosaic analysis to study the cell behaviors that result from chemoFGFR induction. The picture that emerges from these analyses is that de novo organs form through a genetically encoded self-assembly process that is based on the pattern of chemoFGFR induction. In this scenario, cells expressing chemoFGFR aggregate into clusters and epithelialize as they sort out of non-expressing cells. We found that this sorting process occurs through cell rearrangement and slithering, which involves an extensive remodeling of the cell-cell contacts. Chain cells that do not express chemoFGFR can envelop these chemoFGFR expressing cell clusters and form a rim at the cluster periphery. This multi-stage process leads to the establishment of the inside-outside pattern of de novo organs, which is used as a blueprint for cell differentiation. In summary, in this study we provide insights into the mechanisms involved in the self-assembly of organs from a naïve population of progenitor cells

Embryonic Stem Cells

Embryonic stem cells are one of the key building blocks of the emerging multidisciplinary field of regenerative medicine, and discoveries and new technology related to embryonic stem cells are being made at an ever increasing rate. This book provides a snapshot of some of the research occurring across a wide range of areas related to embryonic stem cells, including new methods, tools and technologies; new understandings about the molecular biology and pluripotency of these cells; as well as new uses for and sources of embryonic stem cells. The book will serve as a valuable resource for engineers, scientists, and clinicians as well as students in a wide range of disciplines