• In recent years, interest in the possible molecular regulators of cell proliferation and differentiation in a wide range of regeneration models has grown significantly, but the cell kinetics of this process remain largely a mystery. (mdpi.com)
  • Recent genetic screens utilizing double-stranded RNA technology have uncovered 240 genes that affect regeneration in S. mediterranea. (wikipedia.org)
  • However, the roles of rapamycin in the regulation of planarian regeneration remain to be elucidated. (bvsalud.org)
  • Planarians are flatworms with large populations of stem cells capable of dividing to support adult tissue renewal and regeneration. (biomedcentral.com)
  • We demonstrate Akt signaling is essential for organismal physiology and in late stages of the Akt phenotype the reduction in neoblast numbers may impair regeneration in planarians. (biomedcentral.com)
  • Our results also reveal novel roles for Akt signaling during regeneration, specifically for the timely localization of cell death near the injury site. (biomedcentral.com)
  • This paucity is likely due to the ubiquitous nature of this signaling pathway and the difficulty of analyzing stem cells in their natural environment during physiological cell turnover and regeneration in conventional animal models [ 15 - 17 ]. (biomedcentral.com)
  • Extrapolating this to mammals it may be the case that there is more regenerative ability in mammals than has typically been thought to exist and that inducing regeneration in humans may not be as impossible as it may seem. (ehu.eus)
  • The regenerative abilities of mammals is described and it turns out that there are several examples of classical epimorphic regeneration involving a blastema as exemplified by the regenerating Urodele limb that can be seen in mammals. (ehu.eus)
  • The contributors discuss the dramatic molecular and cellular changes that occur when a regeneration program is initiated, the progenitor cells and morphogenic signals involved, the formation of a blastema, the roles of reprogramming and polyploidy, the diversity of cell fates, the integration of new structures with existing body parts, and our current understanding of why some structures are more resistant to regeneration than others. (cshlpress.com)
  • The importance of technologies (e.g., single-cell RNA-seq) that have been instrumental in deciphering various aspects of regeneration in recent years is emphasized throughout. (cshlpress.com)
  • This volume is therefore essential reading for molecular, cell, and developmental biologists studying regeneration in animals, as well as for all interested in the development of regenerative therapies for clinical application. (cshlpress.com)
  • Regeneration involves the activity of adult stem cells in the branchial sac, which proliferate and produce migratory progenitor cells for tissue and organ replacement. (biologists.com)
  • A pharmacological screen and siRNA-mediated gene knockdown indicated that regeneration requires canonical Wnt signaling. (biologists.com)
  • After bisection across the mid-body, apoptosis occurred only in the regenerating basal fragments, although both fragments contained a part of the branchial sac, suggesting that apoptosis is unilateral at the wound site and the presence of branchial sac stem cells is insufficient for regeneration. (biologists.com)
  • Unidirectional regeneration in the basal chordate Ciona intestinalis involves the proliferation of adult stem cells residing in the branchial sac vasculature and the migration of progenitor cells to the site of distal injury. (biomedcentral.com)
  • However, after the Ciona body is bisected, regeneration occurs in the proximal but not in the distal fragments, even if the latter include a part of the branchial sac with stem cells. (biomedcentral.com)
  • We identified 1149 differentially expressed genes, which were separated into two major modules by weighted gene correlation network analysis, one consisting of mostly upregulated genes correlated with regeneration and the other consisting of only downregulated genes associated with metabolism and homeostatic processes. (biomedcentral.com)
  • siRNA-mediated gene knockdown showed that hsp70 and dnaJb4, but not bag3, are required for progenitor cell targeting and distal regeneration. (biomedcentral.com)
  • Heat shock treatment of distal body fragments activated hsp70 and dnaJb4 expression indicative of a stress response, induced cell proliferation in branchial sac vasculature cells, and promoted distal regeneration. (biomedcentral.com)
  • The chaperone system genes hsp70 , dnaJb4 , and bag3 are significantly upregulated in the branchial sac vasculature following distal injury, defining a stress response that is essential for regeneration. (biomedcentral.com)
  • The stress response is absent from distal fragments, but can be induced by a heat shock, which activates cell division in the branchial sac vasculature and promotes distal regeneration. (biomedcentral.com)
  • This study demonstrates the importance of a stress response for stem cell activation and regeneration in a basal chordate, which may have implications for understanding the limited regenerative activities in other animals, including vertebrates. (biomedcentral.com)
  • Our results indicate that the microbiome of the invertebrate Schmidtea mediterranea, a freshwater planarian, is affected by AgNP exposure at the tested 10 µg/ml concentration. (bvsalud.org)
  • Our findings abrogating Smed-Akt with RNA-interference in the planarian Schmidtea mediterranea led to a gradual decrease in stem cell (neoblasts) numbers. (biomedcentral.com)
  • Thus, we sought to investigate Akt function during cellular turnover and injury using the planarian flatworm Schmidtea mediterranea . (biomedcentral.com)
  • Recently, we described that the genome of S. mediterranea contains a single Akt ortholog termed Smed-Akt , which affects cell division and impairs planarian locomotion [ 22 ]. (biomedcentral.com)
  • The freshwater planarian Dugesia japonica has a powerful regenerative capability and can regenerate a new individual including a complete central nervous system in one week. (bvsalud.org)
  • This organism is well known for its stem cell-based regenerative capability. (biomedcentral.com)
  • in Tricladida planarians this consists of one anterior branch and two posterior branches. (wikipedia.org)
  • Amino acid sequence analysis and orthology analysis via OrthoFinder ver.2.3.8 indicated that the identified major vitellaria-specific novel yolk ferritins were conserved in planarians (Tricladida). (bvsalud.org)
  • Amputation-induced proliferation occurred predominantly within the epidermal and intestinal epithelium, as well as wound-adjacent muscle fibers, where clusters of cells at the same stage of the cell cycle were found. (mdpi.com)
  • In both processes, rapid proliferation gives rise to new tissue, cell fate has to be specified within that tissue, and distinct positional identities have to be established to generate a properly patterned structure. (frontiersin.org)
  • In mammals, Akt is ubiquitously expressed and is associated with regulation of cellular proliferation, metabolism, cell growth and cell death. (biomedcentral.com)
  • Functional disruption of Smed-Akt alters the balance between cell proliferation and cell death leading to systemic impairment of adult tissue renewal. (biomedcentral.com)
  • This study defined the role of Smed-Akt in abnormal cell proliferation triggered by the abrogation of the phosphatase PTEN, an upstream component of the Akt signaling pathway, which is highly mutated in human cancers. (biomedcentral.com)
  • Inhibition of apoptosis did not affect branchial sac stem cell proliferation but prevented the survival of progenitor cells. (biologists.com)
  • For example, a planarian split lengthwise or crosswise will regenerate into two separate individuals. (wikipedia.org)
  • In addition, a non-regenerating species has been induced to regenerate by altering only one signaling pathway. (ehu.eus)
  • The upregulation of HSP70 chaperone genes was verified and their expression confirmed in BS vasculature cells previously identified as stem and progenitor cells. (biomedcentral.com)
  • The knockdown of the yolk ferritin genes caused a decrease in the volume of egg capsules, abnormality in juveniles, and increase in Al content in vitellaria. (bvsalud.org)
  • A planarian is one of the many flatworms of the traditional class Turbellaria. (wikipedia.org)
  • This work provides the first comprehensive and annotated sequence resource for the model planarian G. tigrina , alongside a prioritized list of candidate drug targets conserved among parasitic and free-living flatworms. (biomedcentral.com)
  • The neoblasts are the only dividing cells in planarians and constantly proliferate to repair tissues and support systemic cellular turnover [ 21 ]. (biomedcentral.com)
  • We report the high-coverage sequencing (RNA-Seq) and assembly of the transcriptome of the planarian Girardia tigrina across a set of dynamic conditions. (biomedcentral.com)
  • Planarians move by beating cilia on the ventral dermis, allowing them to glide along on a film of mucus. (wikipedia.org)
  • The reduced neoblast numbers largely affected the maintenance of adult tissues including the nervous and excretory systems and ciliated structures in the ventral epithelia, which impaired planarian locomotion. (biomedcentral.com)
  • mitotically active cells of intact segments do not significantly contribute to the blastemal cellular sources. (mdpi.com)
  • The planarian ortholog Smed-Akt is molecularly conserved providing unique opportunities to analyze the function of Akt during cellular turnover and repair of adult tissues. (biomedcentral.com)
  • Nonetheless, there is limited understanding of how Akt signaling controls the response of stem cells during cellular turnover and tissue injury in the complexity of the whole organism. (biomedcentral.com)
  • Some planarian species have two eye-spots (also known as ocelli) that can detect the intensity of light, while others have several eye-spots. (wikipedia.org)
  • Branchial sac-derived stem cells also replenish recycling cells lining the pharyngeal fissures during homeostatic growth. (biologists.com)
  • Although developing tissues and organisms are known to be more sensitive to toxic compounds, three independent experiments in regenerating worms showed a less pronounced effect of AgNP exposure on the microbiome, possibly because underlying bacterial community changes during development mask the AgNP induced effect. (bvsalud.org)
  • The formation of new cells, tissues, and organs enables animals to recover from day-to-day wear and tear, injury, and disease. (cshlpress.com)
  • Therefore, we propose that damage to and subsequent release of mtDNA elicits a protective signalling response that enhances nDNA repair in cells and tissues, suggesting that mtDNA is a genotoxic stress sentinel. (regenerativemedicine.net)
  • The current study identified major vitellaria-specific proteins in a freshwater planarian, Dugesia ryukyuensis, using peptide mass fingerprinting (PMF) and expression analyses. (bvsalud.org)
  • Gene Ontology annotations were extended to 16,467 proteins. (biomedcentral.com)
  • Using targeted amplification of the bacterial 16S rRNA gene V3-V4 region, two independent experiments on the microbiomes of adult worms revealed a consistent decrease in Betaproteobacteriales after AgNP exposure, mainly attributed to a decrease in Curvibacter and Undibacterium. (bvsalud.org)
  • The cerebral ganglia, a bi-lobed mass of nerve tissue, is sometimes referred to as the planarian "brain" and has been shown to exhibit spontaneous electrophysiological oscillations, similar to the electroencephalographic (EEG) activity of other animals. (wikipedia.org)
  • Thus, Akt signaling regulates neoblast biology and mediates in the distribution of injury-mediated cell death during tissue repair in planarians. (biomedcentral.com)
  • Thousands of copies of the circular mtDNA are present in most cell types that are packaged by TFAM into higher-order structures called nucleoids1. (regenerativemedicine.net)
  • These concerns underpin efforts to extend the utility of planarian biology to the study of nearly-related parasites [ 12 ], mirroring the important role that Caenorhabditis elegans has played in furthering our understanding of the biology of parasitic nematodes [ 13 ]. (biomedcentral.com)
  • As proof of principle, we show that a simple RNAi and pharmacology pipeline in the more convenient planarian model system can inform parasite biology and serve as an efficient screening tool for the identification of lucrative anthelmintic targets. (biomedcentral.com)
  • However, the mechanisms by which Akt signaling regulates stem cell behavior in the complexity of the whole body are poorly understood. (biomedcentral.com)
  • However, in response to amputation, levels of cell death were decreased and failed to localize near the injury site. (biomedcentral.com)
  • We showed previously that cytoplasmic release of mtDNA activates the cGAS STING TBK1 pathway resulting in interferon-stimulated gene (ISG) expression that promotes antiviral immunity4. (regenerativemedicine.net)
  • Chemical inhibitors were used on three targets in pharmacological screens using both planaria and schistosomula, revealing distinct motility phenotypes that were shown to correlate with planarian RNAi phenotypes. (biomedcentral.com)
  • In comparison to their parasitic counterparts, planarians are much more amenable to modern genetic protocols and their culture and maintenance within the laboratory is relatively inexpensive and simple. (biomedcentral.com)
  • Here, we find that persistent mtDNA stress is not associated with basally activated NF-κB signalling or interferon gene expression typical of an acute antiviral response. (regenerativemedicine.net)
  • Members of the free-living genus Planaria are widely interrogated in the realm of stem cell biology due to their remarkable regenerative abilities [ 8 ]. (biomedcentral.com)
  • The excretory system is made of many tubes with many flame cells and excretory pores on them. (wikipedia.org)
  • The hsp70 , dnaJb4 , and bag3 genes were among the highest upregulated genes and were predicted to interact in an HSP70 chaperone system. (biomedcentral.com)
  • There is little empirical evidence to support either view, but some of the best comes from recent phylogenetic analyses of regenerative ability in Planarians which reveals that this property has been lost and gained several times in this group. (ehu.eus)
  • Downregulation of Smed-Akt function also resulted in an increase of cell death throughout the animal. (biomedcentral.com)
  • In cultured primary fibroblasts and cancer cells, the chemotherapeutic drug doxorubicin causes mtDNA damage and release, which leads to cGAS STING dependent ISG activation. (regenerativemedicine.net)
  • Interestingly, the neoblast mitotic response was increased around the amputation area but the regenerative blastema failed to form. (biomedcentral.com)
  • In addition, mtDNA stress in TFAM-deficient mouse melanoma cells produces tumours that are more resistant to doxorubicin in vivo. (regenerativemedicine.net)