Adhesive organ regeneration in Macrostomum lignano

Abstract

BackgroundFlatworms possess pluripotent stem cells that can give rise to all cell types, which allows them to restore lost body parts after injury or amputation. This makes flatworms excellent model systems for studying regeneration. In this study, we present the adhesive organs of a marine flatworm as a simple model system for organ regeneration. Macrostomum lignano has approximately 130 adhesive organs at the ventral side of its tail plate. One adhesive organ consists of three interacting cells: one adhesive gland cell, one releasing gland cell, and one modified epidermal cell, called an anchor cell. However, no specific markers for these cell types were available to study the regeneration of adhesive organs.ResultsWe tested 15 commercially available lectins for their ability to label adhesive organs and found one lectin (peanut agglutinin) to be specific to adhesive gland cells. We visualized the morphology of regenerating adhesive organs using lectin- and antibody staining as well as transmission electron microscopy. Our findings indicate that the two gland cells differentiate earlier than the connected anchor cells. Using EdU/lectin staining of partially amputated adhesive organs, we showed that their regeneration can proceed in two ways. First, adhesive gland cell bodies are able to survive partial amputation and reconnect with newly formed anchor cells. Second, adhesive gland cell bodies are cleared away, and the entire adhesive organ is build anew.ConclusionOur results provide the first insights into adhesive organ regeneration and describe ten new markers for differentiated cells and tissues in M. lignano. The position of adhesive organ cells within the blastema and their chronological differentiation have been shown for the first time. M. lignano can regenerate adhesive organs de novo but also replace individual anchor cells in an injured organ. Our findings contribute to a better understanding of organogenesis in flatworms and enable further molecular investigations of cell-fate decisions during regeneration.Electronic supplementary materialThe online version of this article (doi:10.1186/s12861-016-0121-1) contains supplementary material, which is available to authorized users.

Profiling of adhesive-related genes in the freshwater cnidarianHydra magnipapillataby transcriptomics and proteomics

“…Non-covalent cross-linking of polysaccharide chains by carbohydrate-binding proteins had been proposed to support the adhesive proteins secreted by terrestrial gastropod (Pawlicki et al 2004). Lectin staining and proteins with lectin binding domains have been reported in the adhesive secretions of sea stars, sea urchins, frogs, flatworms, and velvet worms (Fleming et al 2009; Hennebert et al 2010; Graham et al 2013; Toubarro et al 2016; Lengerer et al 2016). An investigation using lectins to study sea stars adhesive (Hennebert et al 2010) showed that some glycans, such as galactose, N-acetylglucosamine, fucose and sialic acid residues were linked to the sea star footprint proteins and could provide both cohesive and adhesive properties.…”

Properties of temporary adhesion systems of marine and freshwater organisms

“…It was proposed that the filaments are required to bear the tension forces during attachment (Tyler, 1976). In the free-living marine flatworm M. lignano, anchor-cell-specific intermediate filaments have been identified (Lengerer et al, 2014(Lengerer et al, , 2016. Upon knockdown of these intermediate filaments, the morphology of the anchor cells and their modified microvilli was severely impaired and the animals failed to efficiently attach themselves to the substrate (Lengerer et al, 2014).…”

“…Carbohydrates are commonly detected in temporary adhesive glands, but their role in the adhesive process is currently unknown. In the flatworms Schmidtea mediterranea (Zayas et al, 2010) and M. lignano (Lengerer et al, 2016), in the sea star A. rubens (Hennebert et al, 2011), and in the cephalopods Idiosepius spp. (von Byern et al, 2008) and E. scolopes (von Byern et al, 2017), lectin (see Glossary) labelling has been used to characterise carbohydrates and indicated the presence of various sugar moieties within the secretory gland cells (Table S2).…”

“…(von Byern et al, 2008) and E. scolopes (von Byern et al, 2017), lectin (see Glossary) labelling has been used to characterise carbohydrates and indicated the presence of various sugar moieties within the secretory gland cells (Table S2). In M. lignano, highresolution microscopy revealed that one lectin (PNA) specifically labelled the outer rim of the adhesive vesicles, indicating the presence of a galactosyl (b-1,3) N-acetylgalactosamine glycoconjugate (see Glossary) in parts of the adhesive vesicles (Lengerer et al, 2016). The reaction of lectins to secreted footprints and footprint-specific proteins was also tested in A. rubens (Hennebert et al, 2011).…”

A phylogenetically informed search for an alternative Macrostomum model species, with notes on taxonomy, mating behavior, karyology, and genome size

“…The free‐living flatworm Macrostomum lignano Ladurner, Schärer, Salvenmoser, Rieger 2005 (Rhabditophora, Macrostomorpha) has emerged as a model for a broad range of research topics (Ladurner, Schärer, Salvenmoser, & Rieger, ), including the biology of aging (Mouton, Grudniewska, Glazenburg, Guryev, & Berezikov, ; Mouton et al, ), bioadhesion (Lengerer, Hennebert, Flammang, Salvenmoser, & Ladurner, ; Lengerer et al, ; Wunderer et al, ), regeneration (Egger, Ladurner, Nimeth, Gschwentner, & Rieger, ; Lengerer et al, ), stem cell biology (Grudniewska et al, ; Ladurner et al, ), and sexual selection (Marie‐Orleach, Janicke, Vizoso, David, & Schärer, ; Schärer, Littlewood, Waeschenbach, Yoshida, & Vizoso, ; Sekii et al, ). This research has led to the establishment of many resources and tools that are crucial for a modern genetic and genomic model, including in situ hybridization (Pfister et al, ), RNA interference (Kuales et al, ; Sekii et al, ), gene expression (Arbore et al, ; Grudniewska et al, ; Lengerer et al, ), genome and transcriptome assemblies (Wasik et al, ; Wudarski et al, ), transgenesis (Marie‐Orleach, Janicke, Vizoso, Eichmann, & Schärer, ; Wudarski et al, ), and a clarification of the phylogenetic context (Janssen et al, ; Schärer et al, ).…”