Gene expression profiling for: activin-2 is required for regeneration of polarity on the planarian anterior-posterior axis
Ontology highlight
ABSTRACT:
ORGANISM(S): Schmidtea mediterranea
PROVIDER: GSE148376 | GEO | 2020/05/15
REPOSITORIES: GEO
Similar Datasets
Project description:Planarians are flatworms and can perform whole-body regeneration. This ability involves a mechanism to distinguish between anterior-facing wounds that require head regeneration and posterior-facing wounds that require tail regeneration. How this head-tail regeneration polarity decision is made is studied to identify principles underlying tissue-identity specification in regeneration. We report that inhibition of activin-2, which encodes an Activin-like signaling ligand, resulted in the regeneration of ectopic posterior-facing heads following amputation. During tissue turnover in uninjured planarians, positional information is constitutively expressed in muscle to maintain proper patterning. Positional information includes Wnts expressed in the posterior and Wnt antagonists expressed in the anterior. Upon amputation, several wound-induced genes promote re-establishment of positional information. The head-versus-tail regeneration decision involves preferential wound induction of the Wnt antagonist notum at anterior-facing over posterior-facing wounds. Asymmetric activation of notum represents the earliest known molecular distinction between head and tail regeneration, yet how it occurs is unknown. activin-2 RNAi animals displayed symmetric wound-induced activation of notum at anterior- and posterior-facing wounds, providing a molecular explanation for their ectopic posterior-head phenotype. activin-2 RNAi animals also displayed anterior-posterior (AP) axis splitting, with two heads appearing in anterior blastemas, and various combinations of heads and tails appearing in posterior blastemas. This was associated with ectopic nucleation of anterior poles, which are head-tip muscle cells that facilitate AP and medial-lateral (ML) pattern at posterior-facing wounds. These findings reveal a role for Activin signaling in determining the outcome of AP-axis-patterning events that are specific to regeneration.
| S-EPMC8057570 | biostudies-literature
Project description:Gene expression profiling for: activin-2 is required for regeneration of polarity on the planarian anterior-posterior axis
| PRJNA624098 | ENA
Project description:Despite long-standing interest, the molecular mechanisms underlying the establishment of anterior-posterior (AP) polarity remain among the unsolved mysteries in metazoans. In the planarians (a family of flatworms), canonical Wnt/beta-catenin signaling is required for posterior specification, as it is in many animals. However, the molecular mechanisms regulating the posterior-specific induction of Wnt genes according to the AP polarity have remained unclear. Here, we demonstrate that Hedgehog (Hh) signaling is responsible for the establishment of AP polarity via its regulation of the transcription of Wnt family genes during planarian regeneration. We found that RNAi gene knockdown of Dugesia japonica patched (Djptc) caused ectopic tail formation in the anterior blastema of body fragments, resulting in bipolar-tails regeneration. In contrast, RNAi of hedgehog (Djhh) and gli (Djgli) caused bipolar-heads regeneration. We show that Patched-mediated Hh signaling was crucial for posterior specification, which is established by regulating the transcription of Wnt genes via downstream Gli activity. Moreover, differentiated cells were responsible for the posterior specification of undifferentiated stem cells through Wnt/beta-catenin signaling. Surprisingly, Djhh was expressed in neural cells all along the ventral nerve cords (along the AP axis), but not in the posterior blastema of body fragments, where the expression of Wnt genes was induced for posteriorization. We therefore propose that Hh signals direct head or tail regeneration according to the AP polarity, which is established by Hh signaling activity along the body's preexisting nervous system.
| S-EPMC2799762 | biostudies-literature
Project description:Axial patterning during planarian regeneration relies on a transcriptional circuit that confers distinct positional information on the two ends of an amputated fragment. The earliest known elements of this system begin demarcating differences between anterior and posterior wounds by 6 h postamputation. However, it is still unknown what upstream events break the axial symmetry, allowing a mutual repressor system to establish invariant, distinct biochemical states at the anterior and posterior ends. Here, we show that bioelectric signaling at 3 h is crucial for the formation of proper anterior-posterior polarity in planaria. Briefly manipulating the endogenous bioelectric state by depolarizing the injured tissue during the first 3 h of regeneration alters gene expression by 6 h postamputation and leads to a double-headed phenotype upon regeneration despite confirmed washout of ionophores from tissue. These data reveal a primary functional role for resting membrane potential taking place within the first 3 h after injury and kick-starting the downstream pattern of events that elaborate anatomy over the following 10 days. We propose a simple model of molecular-genetic mechanisms to explain how physiological events taking place immediately after injury regulate the spatial distribution of downstream gene expression and anatomy of regenerating planaria.
| S-EPMC6401388 | biostudies-literature
Project description:Variability of regenerative potential among animals has long perplexed biologists. Based on their amazing regenerative abilities, planarians have become important models for understanding the molecular basis of regeneration; however, planarian species with limited regenerative abilities are also found. Despite the importance of understanding the differences between closely related, regenerating and non-regenerating organisms, few studies have focused on the evolutionary loss of regeneration, and the molecular mechanisms leading to such regenerative loss remain obscure. Here we examine Procotyla fluviatilis, a planarian with restricted ability to replace missing tissues, utilizing next-generation sequencing to define the gene expression programs active in regeneration-permissive and regeneration-deficient tissues. We found that Wnt signaling is aberrantly activated in regeneration-deficient tissues. Remarkably, down-regulation of canonical Wnt signaling in regeneration-deficient regions restores regenerative abilities: blastemas form and new heads regenerate in tissues that normally never regenerate. This work reveals that manipulating a single signaling pathway can reverse the evolutionary loss of regenerative potential. RNA-seq experiments to identify gene expression changes following amputation in body regions with variable regenerative potential. Adult Procotyla fluviatilis were amputated at sites either anterior or posterior to the pharynx. After 24 hours post-amputation, tissues near the amputation site were excised and RNA was extracted. Similar tissues were excised from uncut control animals. Samples were processed for RNA-seq using Illumina procedures. We generated a de novo P. fluviatilis transcriptome and used RNA sequencing (RNA-seq) to characterize transcripts from excised tissue fragments in Reg+ and Reg- body regions 24 hours post-amputation. We performed parallel analyses on tissues excised from intact animals at identical body regions to account for regional differences in transcripts, thereby identifying changes resulting from amputation. Samples A1-A3 = Regeneration-proficient (Reg+) tissue excision 24 hours after amputation. Samples B1-B3 = Tissue excision from regeneration-proficient (Reg+) region but not amputated. Samples C1-C3 = Tissue excision from regeneration-deficient (Reg-) tissues 24 hours after amputation. Samples D1, D3-D4 = Tissue excision from regeneration-deficient (Reg-) region that was not amputated.
2013-07-04 | E-GEOD-48497 | biostudies-arrayexpress
Project description:Whole cell extracts from mouse Th17 cells treated with activin A were profiled with extensive fractionation and bottom-up proteomics
2020-05-18 | PXD017757 | Pride
Project description:Members of the transforming growth factor (TGF)-β superfamily play essential roles in the pluripotency, self-renewal, and differentiation of embryonic stem cells. While bone morphogenic proteins maintain pluripotency of undifferentiated mouse ES cells, the role of Activin/Nodal signaling is less clear. To determine the target genes of Activin/Nodal-Smad2 signaling in undifferentiated embryonic stem cells, changes in gene expression were examined following stimulation with recombinant Activin (2 hours) or after inhibition of Activin/Nodal with SB431542 (24 hours) using defined media culture conditions with LIF and 20 ng/mL BMP4. SB431542 is a specific inhibitor of ALK4/5/7 receptors and antagonizes both Activin and Nodal signaling. Via western analysis, Activin stimulation increased pSmad2 in ES cells after 2 hours, and treatment with SB431542 for 24 hours virtually eliminated pSmad2. Total Smad2 expression remained unchanged through these manipulations. RNA from cells treated with Activin or SB431542 was extracted by standard methods with Qiagen RNeasy columns. The RNA was analyzed with the Mouse Genome 430A Array from Affymetrix. Samples were performed in duplicate, and RNA from cells treated with Activin or SB431542 was compared to untreated embryonic stem cells.
2009-08-31 | GSE17879 | GEO
Project description:Doxorubicin is a widely used and effective anthracycline chemotherapy drug. However, it causes cardiotoxicity and also a few negative effects on skeletal muscle as well. As a result, cancer treatment might actually worsen cancer-induced cachexia and consequently the prognosis of the disease. Inhibiting myostatin/activin signaling is known to increase muscle size. This pathway blockade by soluble activin receptor IIB (sAcvR2B-Fc) has also prolonged survival in cancer, even of animals in which tumor growth is not inhibited. It is not known, however, whether blocking this pathway affects chemotherapy-induced muscle wasting. We found that doxorubicin induces muscle atrophy which is prevented by a blocker for activin receptor 2B ligands (sAcvR2B-Fc).
2016-09-25 | GSE77745 | GEO
Project description:Doxorubicin is a widely used and effective anthracycline chemotherapy drug. However, it causes cardiotoxicity and also a few negative effects on skeletal muscle as well. As a result, cancer treatment might actually worsen cancer-induced cachexia and consequently the prognosis of the disease. Inhibiting myostatin/activin signaling is known to increase muscle size. This pathway blockade by soluble activin receptor IIB (sAcvR2B-Fc) has also prolonged survival in cancer, even of animals in which tumor growth is not inhibited. It is not known, however, whether blocking this pathway affects chemotherapy-induced muscle wasting. We found that doxorubicin induces muscle atrophy which is prevented by a blocker for activin receptor 2B ligands (sAcvR2B-Fc)
2017-12-04 | GSE97642 | GEO
Project description:Activin A is known to induce endodermal differentiation in human embryonic stem cells under low-serum or certain defined media conditions. To gain insights into global gene expression changes during Activin A-induced differentiation, gene expression was monitored by means of microarrays in short intervals until 4 days of treatment. Keywords: Differentiation timecourse experiment
2008-03-12 | GSE9063 | GEO