Biology subjects

Koziol, U.

Publications and source records attributed to Koziol, U..

10 recordsLinked to original sources

bioRxiv2026

Persistence of regenerative stem cells provides a cellular basis for the parasitostatic activity of albendazole against Echinococcus multilocularis

Albendazole (ABZ) is the mainstay of chemotherapy for alveolar echinococcosis caused by the larval stage of Echinococcus multilocularis, but its activity is predominantly parasitostatic rather than parasiticidal. The cellular basis of this remarkable parasite persistence remains poorly understood. Here, we investigated the effects of sustained ABZ exposure on the germinative stem cells that drive metacestode growth and regeneration and examined whether differential beta-tubulin isoform usage could contribute to their drug susceptibility. ABZ rapidly impaired microtubule-dependent tegumental transport and caused pronounced damage to metacestode vesicles. In contrast, proliferative germinative cells (GC) persisted during prolonged and continuous ABZ exposure. Importantly, cells surviving 14 to 28 days of treatment retained developmental competence, regenerated metacestode vesicles following drug withdrawal, and, after extended exposure to 10 micromolar ABZ, remained capable of generating parasite tissue following transplantation into a permissive host. Transcriptomic and immunohistochemical analyses identified the Y200 containing beta tubulin isoform Tub2 as a major metacestode beta tubulin that is almost exclusively associated with the proliferative GC lineage. Tub2 was present in virtually all S phase cells, colocalized with established GC markers, localized to mitotic spindles, and Tub2+ cells persisted during prolonged ABZ and ABZSO exposure. Structural analysis further revealed an E198-Y200 interaction in Tub2, providing a structural correlate of the resistance-associated Y200 configuration. Together, these findings provide a cellular explanation for the predominantly parasitostatic activity of benzimidazoles against E. multilocularis. ABZ profoundly damages parasite tissue while sparing a regenerative cell compartment capable of re-establishing metacestode growth after drug withdrawal. They further identify GC-associated Tub2 as a plausible molecular contributor to this persistence and as a potential target for curative anti-Echinococcus chemotherapy.

cell biology↗

bioRxiv2026

Coordinated development of the male and female reproductive systems in the cestode Hymenolepis microstoma

BackgroundCestodes have complex hermaphroditic reproductive systems that produce massive numbers of eggs. This reproductive output is made possible by the continuous production of serially repeated sets of reproductive systems (proglottids). However, their reproductive development remains poorly understood. ResultsWe characterized reproductive development in the model cestode Hymenolepis microstoma by analyzing markers of cell proliferation, meiosis, and differentiation along the series of proglottids. Reproductive development begins with the formation of a central genital primordium, from which the reproductive ducts and gonads differentiate. Development is proterandrous, and testicular development is prolonged. In contrast, female reproductive development occurs over a short interval and is characterized by the coordinated differentiation of the ovary and vitelline gland. Entry of oocytes into meiosis is almost synchronous, and paralleled by cell proliferation in the vitelline gland. Subsequent growth of arrested oocytes and differentiation of vitelline cells occur in parallel. Insemination coincides with the onset of ovarian meiosis, indicating a close temporal coordination between male and female reproductive development. Finally, we show that gametogenesis and insemination proceed in adult worms maintained in vitro. ConclusionsOur findings show the coordination of reproductive development in a self-fertile hermaphrodite, and provide an experimental system for studying reproductive development in cestodes.

Developmental Biology↗

bioRxiv2026

Comparative proteomics reveals a conserved core of tegumental proteins in parasitic flatworms.

Parasitic flatworms, including cestodes and trematodes, are covered by a specialized syncytial tegument that mediates nutrient uptake and host-parasite interactions. While the tegument of trematodes has been extensively characterized, its molecular composition in cestodes remains largely unknown. In this work, we performed a comparative proteomic analysis of the tegument of three cestode species, including larval and adult stages: Hymenolepis microstoma, Mesocestoides corti (syn. M. vogae) and Echinococcus multilocularis. Using stringent enrichment criteria relative to whole-worm extracts, we identified hundreds of tegument-enriched proteins in each species. Comparative analyses revealed a conserved core of tegumental proteins shared among all three species, including members of the Tegument Allergen-Like (TAL) family, vesicular trafficking components and calcium-sensing proteins, and identified candidates for nutrient uptake activities such as glucose and nucleoside transporters. Further comparative analyses revealed a set of shared tegumental proteins with the trematode Schistosoma mansoni, including conserved proteins that are specific to parasitic flatworms, supporting the existence of a conserved ancestral tegumental proteome. Finally, we confirmed tegumental expression of several candidate genes in H. microstoma and E. multilocularis, and demonstrated regionally restricted gene expression among tegumental cytons, suggesting functional specialization within the syncytial tegument. Altogether, these results reveal an evolutionarily conserved composition of the tegument of parasitic flatworms, providing a foundation for future work targeting this critical host-parasite interface.

cell biology↗

bioRxiv2025

Canonical WNT signalling governs Echinococcus metacestode development

Alveolar echinococcosis (AE) is a lethal zoonosis caused by infiltrative growth of the metacestode larva of the tapeworm Echinococcus multilocularis in host organs. We previously showed that the Echinococcus metacestode is an evolutionarily unique, broadly posteriorized tissue, leading us to hypothesize that canonical WNT (cWNT) signalling--which patterns the body axis across metazoans--might be critical for metacestode formation. Here, we report effective RNAi-mediated knockdown of the E. multilocularis {beta}-catenin gene (bcat-1), the central effector of cWNT signalling, in a primary parasite cell culture system that produces metacestode vesicles. bcat-1(RNAi) cultures were markedly impaired in vesicle formation, exhibited stem-cell hyperproliferation, and displayed disrupted muscle-fibre organisation. Genome-wide transcriptomics revealed a general anteriorization of gene expression, and in situ hybridization showed an overproduction of cells expressing head-inducing factors such as sfrp upon bcat-1 knockdown. Conversely, metacestode-specific genes--including the tegumental factors muc-1, TNFR, and antigen B--as well as the posterior marker post2b were significantly downregulated, consistent with the observed vesicle-formation defects. In situ analyses further identified anterior markers--frizzled-10, nou-darake, notum, and follistatin--that were overexpressed in bcat-1(RNAi) cultures and localized to the future anterior pole at the earliest stages of protoscolex formation. Finally, pharmacological inhibition of WNT signalling with pyrvinium pamoate caused complete loss of posterior tissue in Echinococcus protoscoleces, killed metacestode vesicles, and reduced stem-cell proliferation at nanomolar concentrations. Together, these findings establish a central role for cWNT signalling in directing Echinococcus body-axis formation and the posteriorization events driving metacestode growth within the host, providing insight into asexual parasite proliferation mediated by this biologically unique larval stage and pointing to potential targets for chemotherapy against AE. Author SummaryAlveolar echinococcosis (AE) is a lethal disease caused by the cancer-like growth of the metacestode larva of the tapeworm Echinococcus multilocularis. From a developmental perspective, the Echinococcus metacestode is an unusual biological structure and even atypical among tapeworms. Previous work indicated that metacestode formation involves re-patterning of the body axis, eliminating head structures and producing broadly posteriorized tissue. How this is controlled at the molecular and cellular levels, however, was unknown. In this study, we perturbed expression of the {beta}-catenin gene (bcat-1), a central regulator of canonical WNT signalling, using RNA interference (RNAi). bcat-1(RNAi) parasite cultures failed to generate metacestode vesicles and instead showed stem-cell hyperproliferation and muscle-cell distortion. Genes required for posteriorized metacestode tissue were downregulated, whereas genes directing head formation in adult worms (follistatin, sfrp, fz10, ndk) were upregulated, indicating a general anteriorization of the culture system. Pharmacological inhibition of WNT signalling with pyrvinium pamoate caused complete loss of posterior structures in protoscoleces, reduced stem-cell proliferation, and killed metacestode tissue. These findings identify {beta}-catenin and the canonical WNT pathway as crucial regulators of the posteriorization that underlies metacestode formation. Given that WNT signalling is deregulated in many human cancers and that small-molecule inhibitors are available, our results suggest new avenues for anti-AE drug development.

developmental biology↗

bioRxiv2025

Albendazole specifically disrupts microtubules and protein turnover in the tegument of the cestode Mesocestoides corti

Parasitic flatworms, such as cestodes and trematodes, are covered by a syncytial tissue known as the tegument. It consists of a superficial band of cytoplasm (the distal tegument) that is connected by cytoplasmic bridges to multiple cell bodies (cytons) that lay beneath the basal lamina and contain the nuclei. We characterized the cytoskeleton of the tegument of the model cestode Mesocestoides corti and determined the effects of albendazole and albendazole sulfoxide on its organization. These anthelmintics are known to target beta-tubulin in helminths, and their effects have been extensively studied in nematodes, but the specific cells and tissues that are affected are not well understood in parasitic flatworms. Using antibodies that detect different tubulin subunits and post-translational modifications, we show that microtubules in the distal tegument have a unique organization, with bouquets of microtubules radiating from the cytoplasmic bridges, suggesting a role in intracellular traffic. In contrast, actin filaments were largely absent from the distal tegument. The microtubules of the tegument were specifically sensitive to low, chemotherapeutically relevant concentrations of albendazole and albendazole sulfoxide. This was correlated with the accumulation of secretory material in the cytons, and low concentrations of albendazole strongly reduced the incorporation of newly synthesized proteins in the distal tegument, as determined by metabolic labeling. Unexpectedly, albendazole also induced a global decrease in protein synthesis, which was independent of the activation of the unfolded protein response. Our work identifies the tegument as a sensitive target of benzimidazoles in cestodes and indicates that translational inhibition may contribute to the anthelmintic effect of benzimidazoles. Author SummaryInfections caused by cestodes, such as Echinococcus spp. and Taenia spp., pose a large burden on global human health. These parasites are covered by a very particular epidermis, a syncytial tegument, which is the only contact surface between the parasite and the host. The only chemotherapy available for these infections are benzimidazoles, such as albendazole. From work in other helminths, it is well known that beta-tubulin is the molecular target of benzimidazoles, however, the affected cells and tissues are not known in flatworms. Here, we use the model cestode Mesocestoides corti to address some basic features of the tegument such as the organization of the cytoskeleton, and the effects of therapeutically relevant concentrations of albendazole in this tissue. We found that microtubules are abundant and highly organized in the tegument, and are specifically sensitive to albendazole, in comparison with other cells and tissues. Albendazole reduced the incorporation of new proteins in the tegument and produced an unexpected overall decrease in protein synthesis, which may also be of relevance for chemotherapy. Our results indicate that the tegument is a sensitive cellular target of benzimidazoles.

cell biology↗

bioRxiv2024

Evolutionary analysis of genome-specific duplications in flatworm genomes

Platyhelminthes, also known as flatworms, is a phylum of bilaterian invertebrates infamous for their parasitic representatives. The classes Cestoda, Monogenea, and Trematoda comprise parasitic helminths inhabiting multiple hosts, including fishes, humans, and livestock, and are responsible for considerable economic damage and burden on human health. As in other animals, the genomes of flatworms have a wide variety of paralogs, genes related via duplication, whose origins could be mapped throughout the evolution of the phylum. Through in-silico analysis, we studied inparalogs, i.e., genome-specific duplications, focusing on their biological functions, expression changes, and evolutionary rate. These genes are assumed to be key players in the adaptation process of species to each particular niche. Our results showed that genes associated with specific functions, such as response to stress, ion binding, oxidoreductase activity, and peptidase, are overrepresented among inparalogs. This trend is conserved among species from different classes, including free-living species. Available expression data from Schistosoma mansoni, a parasite from the trematode class, demonstrated high conservation of the expression patterns between inparalogs, but with notable exceptions, which also display evidence of rapid evolution. We discuss how natural selection may operate to maintain these genes and the particular duplication models that fit better to the observations. Our results support the critical role of gene duplication in the evolution of flatworms.

evolutionary biology↗

bioRxiv2023

Segmentation in tapeworms as a modified form of flatworm posterior regeneration involving Wnt and Hedgehog signalling

Tapeworms are parasitic flatworms that lack key features conventionally used to define the head-tail axis in free-living organisms, resulting in long standing questions regarding the true orientation of their main body axis. As adults, most tapeworms also exhibit a segmented body which has been considered an adaptation unique to the group. Anteroposterior (AP) patterning in free-living flatworms is controlled by {beta}-catenin-dependent Wnt signalling and positional control genes are expressed by their musculature in highly regionalised domains. Here we investigate the expression of Wnt and Hedgehog components during the strobilar phase of the tapeworm life cycle during which larval tissues are lost and replaced through the continuous production of new tissues. Results reveal previously unidentified centres of signalling associated with their neuromuscular system and show that segments are marked by secondary, AP axes in agreement with the polarity of the primary body axis. Neuromuscular expression and communication between Wnt and Hedgehog signalling is consistent with embryonic and regenerative growth in planarians and is a common mechanism for establishing AP-polarised boundaries in a diverse range of segmented animals. Taken together our results suggest that segmentation in tapeworms represents a modified form of posterior regeneration, a common feature among flatworms.

developmental biology↗

bioRxiv2023

Stem cell proliferation and differentiation during larval metamorphosis of the model tapeworm Hymenolepis microstoma

Tapeworm larvae cause important diseases in humans and domestic animals. During infection, the first larval stage undergoes a metamorphosis where tissues are formed de novo from a population of stem cells called germinative cells. This process is difficult to study for human pathogens, as these larvae are infectious and difficult to maintain in the laboratory. In this work, we analyzed cell proliferation and differentiation during larval metamorphosis in the model tapeworm Hymenolepis microstoma, by in vivo labelling of proliferating cells with the thymidine analogue 5-ethynyl-2'-deoxyuridine (EdU), tracing their differentiation with a suite of specific molecular markers for different cell types. Proliferating cells are very abundant and fast-cycling during early metamorphosis: the total number of cells duplicates every ten hours, and the length of G2 is only 75 minutes. New tegumental, muscle and nerve cells differentiate from this pool of proliferating germinative cells, and these processes are very fast, as differentiation markers for neurons and muscle cells appear within 24 hours after exiting the cell cycle, and fusion of new cells to the tegumental syncytium can be detected after only 4 hours. Tegumental and muscle cells appear from early stages of metamorphosis (24 to 48 hours post-infection); in contrast, most markers for differentiating neurons appear later, and the detection of synapsin and neuropeptides correlates with scolex retraction. Finally, we identified populations of proliferating cells that express conserved genes associated with neuronal progenitors and precursors, suggesting the existence of tissue-specific lineages among germinative cells. These results provide for the first time a comprehensive view of the development of new tissues during tapeworm larval metamorphosis, providing a framework for similar studies in human and veterinary pathogens.

developmental biology↗

bioRxiv2021

Insights into in vivo adipocyte differentiation through cell-specific labeling in zebrafish

White adipose tissue hyperplasia has been shown to be crucial for handling excess energy in healthy ways. Though adipogenesis mechanisms have been underscored in vitro, we lack information on how tissue and systemic factors influence the differentiation of new adipocytes. While this could be studied in zebrafish, adipocyte identification currently relies on neutral lipid labeling, thus precluding access to cells in early stages of differentiation. Here we report the generation and analysis of a zebrafish line with the transgene fabp4(-2.7):EGFPcaax. In vivo confocal microscopy of the pancreatic and abdominal visceral depots of transgenic larvae, revealed the presence of labeled mature adipocytes as well as immature cells in earlier stages of differentiation. Through co-labeling for blood vessels, we observed a close interaction of differentiating adipocytes with endothelial cells through cell protrusions. Finally, we implemented hyperspectral imaging and spectral phasor analysis in Nile Red labeled transgenic larvae and revealed the lipid metabolic transition towards neutral lipid accumulation of differentiating adipocytes. Altogether our work presents the characterization of a novel adipocyte-specific label in zebrafish and uncovers previously unknown aspects of in vivo adipogenesis. Summary statementAnalysis of the differentiation of adipocytes in vivo through cell-specific labeling in zebrafish, revealed their early interaction with blood vessels as well as early lipid metabolic changes.

developmental biology↗

bioRxiv2018

The role of fibroblast growth factor signalling in Echinococcus multilocularis development and host-parasite interaction

BackgroundAlveolar echinococcosis (AE) is a lethal zoonosis caused by the metacestode larva of the tapeworm Echinococcus multilocularis. The infection is characterized by tumour-like growth of the metacestode within the host liver, leading to extensive fibrosis and organ-failure. The molecular mechanisms of parasite organ tropism towards the liver and influences of liver cytokines and hormones on parasite development are little studied to date.\n\nMethodology/Principal findingsWe show that the E. multilocularis larval stage expresses three members of the fibroblast growth factor (FGF) receptor family with homology to human FGF receptors. Using the Xenopus expression system we demonstrate that all three Echinococcus FGF receptors are activated in response to human acidic and basic FGF, which are present in the liver. In all three cases, activation could be prevented by addition of the tyrosine kinase inhibitor BIBF 1120, which is used to treat human cancer. At physiological concentrations, acidic and basic FGF significantly stimulated the formation of metacestode vesicles from parasite stem cells in vitro and supported metacestode growth. Furthermore, the parasites mitogen activated protein kinase signalling system was stimulated upon addition of human FGF. The survival of metacestode vesicles and parasite stem cells were drastically affected in vitro in the presence of BIBF 1120.\n\nConclusions/SignificanceOur data indicate that mammalian FGF, which is present in the liver and upregulated during fibrosis, supports the establishment of the Echinococcus metacestode during AE by acting on an evolutionarily conserved parasite FGF signalling system. These data are valuable for understanding molecular mechanisms of organ tropism and host-parasite interaction in AE. Furthermore, our data indicate that the parasites FGF signalling systems are promising targets for the development of novel drugs against AE.\n\nAuthor summaryTo ensure proper communication between their different cell populations, animals rely on secreted hormones and cytokines that act on receptors of target cells. Most of the respective cytokines, such as FGFs, evolved over 500 million years ago and are present in similar form in all animals, including parasitic worms. The authors of this study show that the metacestode larva of the tapeworm E. multilocularis, which grows like a malignant tumor within the host liver, expresses molecules with homology to FGF receptors from mammals. The authors show that human FGF, which is abundantly present in the liver, stimulates metacestode development and that all parasite FGF receptors are activated by human FGF, despite 500 million years of evolutionary distance between both systems. This indicates that cells of the Echinococcus metacestode can directly communicate with cells of the mammalian host using evolutionarily conserved signaling molecules. This mode of host-pathogen interaction is unique for helminths and does not occur between mammals and single-celled pathogens such as protozoans or bacteria. The authors finally demonstrate that BIBF 1120, a drug used to treat human cancer, targets the Echinococcus FGF receptors and leads to parasite death. This opens new ways for the development of anti-parasitic drugs.

zoology↗