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Project description:Wnt signaling control by KDM5C during development impacts lifelong cognition
| PRJNA1000635 | ENA
Project description:Optogenetics uses light-inducible protein-protein interactions to precisely control the timing, localization, and intensity of signaling activity. The precise spatial and temporal resolution of this emerging technology has proven extremely attractive to the study of embryonic development, a program faithfully replicated to form the same organism from a single cell. We have previously performed a comparative study for optogenetic activation of receptor tyrosine kinases, where we found that the cytoplasm-to-membrane translocation-based optogenetic systems outperform the membrane-anchored dimerization systems in activating the receptor tyrosine kinase signaling in live Xenopus embryos. Here, we determine if this engineering strategy can be generalized to other signaling pathways involving membrane-bound receptors. As a proof of concept, we demonstrate that the cytoplasm-to-membrane translocation of the low-density lipoprotein receptor-related protein-6 (LRP6), a membrane-bound coreceptor for the canonical Wnt pathway, triggers Wnt activity. Optogenetic activation of LRP6 leads to axis duplication in developing Xenopus embryos, indicating that the cytoplasm-to-membrane translocation of the membrane-bound receptor could be a generalizable strategy for the construction of optogenetic systems.
| S-EPMC8380706 | biostudies-literature
Project description:Mutations in leucine-rich repeat kinase 2 (lrrk2) are the most common genetic cause of Parkinson's disease. Difficulty in elucidating the pathogenic mechanisms resulting from disease-associated Lrrk2 variants stems from the complexity of Lrrk2 function and activities. Lrrk2 contains multiple protein-protein interacting domains, a GTPase domain, and a kinase domain. Lrrk2 is implicated in many cellular processes including vesicular trafficking, autophagy, cytoskeleton dynamics, and Wnt signaling. Here, we generated a zebrafish lrrk2 allelic series to study the requirements for Lrrk2 during development and to dissect the importance of its various domains. The alleles are predicted to encode proteins that either lack all functional domains (lrrk2sbu304 ), the GTPase, and kinase domains (lrrk2sbu71 ) or the kinase domain (lrrk2sbu96 ). All three lrrk2 mutants are viable, morphologically normal, and display wild-type-like locomotion. Because Lrrk2 modulates Wnt signaling in some contexts, we assessed Wnt signaling in all three mutant lines. Analysis of Wnt signaling by studying the expression of target genes using whole mount RNA in situ hybridization and a transgenic Wnt reporter revealed wild-type domains of Wnt activity in each of the mutants. However, we found that Wnt pathway activation is attenuated in lrrk2sbu304/sbu304 , which lacks both scaffolding and catalytic domains, but not in the other alleles during late embryogenesis. This supports a model in which Lrrk2 scaffolding functions are key to a context-dependent role in promoting canonical Wnt signaling.
| S-EPMC7643907 | biostudies-literature
Project description:Nucleophosmin (NPM1) is a ubiquitous multifunctional phosphoprotein with both oncogenic and tumor suppressor functions. Mutations of the NPM1 gene are the most frequent genetic alterations in acute myeloid leukemia (AML) and result in the expression of a mutant protein with aberrant cytoplasmic localization, NPMc+. Although NPMc+ causes myeloproliferation and AML in animal models, its mechanism of action remains largely unknown. Here we report that NPMc+ activates canonical Wnt signaling during the early phases of zebrafish development and determines a Wnt-dependent increase in the number of progenitor cells during primitive hematopoiesis. Coherently, the canonical Wnt pathway is active in AML blasts bearing NPMc+ and depletion of the mutant protein in the patient derived OCI-AML3 cell line leads to a decrease in the levels of active β-catenin and of Wnt target genes. Our results reveal a novel function of NPMc+ and provide insight into the molecular pathogenesis of AML bearing NPM1 mutations.
| S-EPMC5342418 | biostudies-literature
Project description:BackgroundThe formation of the vertebrate kidney is tightly regulated and relies on multiple evolutionarily conserved inductive events. These are present in the complex metanephric kidney of higher vertebrates, but also in the more primitive pronephric kidney functional in the larval stages of amphibians and fish. Wnts have long been viewed as central in this process. Canonical β-Catenin-dependent Wnt signaling establishes kidney progenitors and non-canonical β-Catenin-independent Wnt signaling participate in the morphogenetic processes that form the highly sophisticated nephron structure. While some individual Wnt signaling components have been studied extensively in the kidney, the overall pathway has not yet been analyzed in depth.Methodology/principal findingsHere we report a detailed expression analysis of all Wnt ligands, receptors and several downstream Wnt effectors during pronephros development in Xenopus laevis using in situ hybridization. Out of 19 Wnt ligands, only three, Wnt4, Wnt9a and Wnt11, are specifically expressed in the pronephros. Others such as Wnt8a are present, but in a broader domain comprising adjacent tissues in addition to the kidney. The same paradigm is observed for the Wnt receptors and its downstream signaling components. Fzd1, Fzd4, Fzd6, Fzd7, Fzd8 as well as Celsr1 and Prickle1 show distinct expression domains in the pronephric kidney, whereas the non-traditional Wnt receptors, Ror2 and Ryk, as well as the majority of the effector molecules are rather ubiquitous. In addition to this spatial regulation, the timing of expression is also tightly regulated. In particular, non-canonical Wnt signaling seems to be restricted to later stages of pronephros development.Conclusion/significanceTogether these data suggest a complex cross talk between canonical and non-canonical Wnt signaling is required to establish a functional pronephric kidney.
| S-EPMC3197532 | biostudies-literature
Project description:BACKGROUND: The high-mobility-group (HMG) proteins are the most abundant non-histone chromatin-associated proteins. HMG proteins are present at high levels in various undifferentiated tissues during embryonic development and their levels are strongly reduced in the corresponding adult tissues, where they have been implicated in maintaining and activating stem/progenitor cells. Here we deciphered the role of the high-mobility-group AT-hook protein 2 (HMGA2) during lung development by analyzing the lung of Hmga2-deficient mice (Hmga2(-/-)). RESULTS: We found that Hmga2 is expressed in the mouse embryonic lung at the distal airways. Analysis of Hmga2(-/-) mice showed that Hmga2 is required for proper cell proliferation and distal epithelium differentiation during embryonic lung development. Hmga2 knockout led to enhanced canonical WNT signaling due to an increased expression of secreted WNT glycoproteins Wnt2b, Wnt7b and Wnt11 as well as a reduction of the WNT signaling antagonizing proteins GATA-binding protein 6 and frizzled homolog 2. Analysis of siRNA-mediated loss-of-function experiments in embryonic lung explant culture confirmed the role of Hmga2 as a key regulator of distal lung epithelium differentiation and supported the causal involvement of enhanced canonical WNT signaling in mediating the effect of Hmga2-loss-of-fuction. Finally, we found that HMGA2 directly regulates Gata6 and thereby modulates Fzd2 expression. CONCLUSIONS: Our results support that Hmga2 regulates canonical WNT signaling at different points of the pathway. Increased expression of the secreted WNT glycoproteins might explain a paracrine effect by which Hmga2-knockout enhanced cell proliferation in the mesenchyme of the developing lung. In addition, HMGA2-mediated direct regulation of Gata6 is crucial for fine-tuning the activity of WNT signaling in the airway epithelium. Our results are the starting point for future studies investigating the relevance of Hmga2-mediated regulation of WNT signaling in the adult lung within the context of proper balance between differentiation and self-renewal of lung stem/progenitor cells during lung regeneration in both homeostatic turnover and repair after injury.
| S-EPMC4064517 | biostudies-literature
Project description:Many ciliopathies have clinical features that include tooth malformations but how these defects come about is not clear. Here we show that genetic deletion of the motor protein Kif3a in dental mesenchyme results in an arrest in odontogenesis. Incisors are completely missing, and molars are enlarged in Wnt1(Cre+)Kif3a(fl/fl) embryos. Although amelogenesis and dentinogenesis initiate in the molar tooth bud, both processes terminate prematurely. We demonstrate that loss of Kif3a in dental mesenchyme results in loss of Hedgehog signaling and gain of Wnt signaling in this same tissue. The defective dental mesenchyme then aberrantly signals to the dental epithelia, which prompts an up-regulation in the Hedgehog and Wnt responses in the epithelia and leads to multiple attempts at invagination and an expanded enamel organ. Thus, the primary cilium integrates Hedgehog and Wnt signaling between dental epithelia and mesenchyme, and this cilia-dependent integration is required for proper tooth development.
| S-EPMC3988628 | biostudies-literature
Project description:Recent studies using small molecule antagonists have revealed that the poly(ADP-ribose) polymerases (PARPs) Tankyrase 1 and 2 are critical regulators of canonical Wnt signaling in some cellular contexts. However, the absence of any activity during zebrafish embryogenesis suggested that the tankyrases may not be general/core components of the Wnt pathway. Here, we show that Tnks1 and 2 are broadly expressed during mouse development and are essential during kidney and lung development. In the kidney, blockage of tankyrase activity phenocopies the effect of blocking production of all Wnt ligands. Tankyrase inhibition can be rescued by activation of beta-catenin demonstrating its specificity for the Wnt pathway. In addition, treatment with tankyrase inhibitors appears to be completely reversible in some cell types. These studies suggest that the tankyrases are core components of the canonical Wnt pathway and their inhibitors should enjoy broad usage as antagonists of Wnt signaling.
| S-EPMC2925040 | biostudies-literature
Project description:Mesenchymal stem/progenitor cells are essential for tissue development and repair throughout life, but how they are maintained under chronic differentiation pressure is not known. Using single-cell transcriptomics of human progenitor cells we find that adipose differentiation stimuli elicit two cellular trajectories: one toward mature adipocytes and another toward a pool of non-differentiated cells that maintain progenitor characteristics. These cells are induced by transient Wnt pathway activation and express numerous extracellular matrix genes and are therefore named structural Wnt-regulated adipose tissue cells. We find that the genetic signature of structural Wnt-regulated adipose tissue cells is present in adult human adipose tissue and adipose tissue developed from human progenitor cells in mice. Our results suggest a mechanism whereby adipose differentiation occurs concurrently with the maintenance of a mesenchymal progenitor cell pool, ensuring tissue development, repair and appropriate metabolic control over the lifetime.
| S-EPMC10290956 | biostudies-literature
Project description:In Xenopus, two signaling systems, maternal beta-Catenin and Nodal-related, are required for induction of the Spemann organizer and establishment of the body plan. By screening cDNA macroarrays for genes activated by these two signaling pathways, we identified Xenopus xBtg-x, a novel member of the Btg/Tob gene family of antiproliferative proteins. We show that xBtg-x is expressed in the dorsal mesendoderm (Spemann organizer tissue) of gastrula stage embryos and that its expression is regulated by both beta-Catenin and Nodal-related signals. Microinjection of synthetic xBtg-x mRNA into Xenopus embryos induced axis duplication and completely rescued the ventralizing effects of UV irradiation through the activation of the canonical Wnt/beta-Catenin signaling pathway. Interestingly, xBtg-x stimulated beta-Catenin-dependent transcription without affecting the stability of beta-Catenin protein. These data suggest that xBtg-x is a novel component of the Wnt/beta-Catenin signaling pathway regulating early embryonic patterning.
| S-EPMC2278116 | biostudies-literature