The vertebrate eye is a highly specialized sensory organ, which is derived from the anterior neural plate, head surface ectoderm, and neural crest-derived mesenchyme. The single central eye field, generated from the anterior neural plate, divides to give rise to the optic vesicle, which evaginates toward the head surface ectoderm. Subsequently, the surface ectoderm, in conjunction with the optic vesicle invaginates to form the lens vesicle and double-layered optic cup, respectively. This complex process is controlled by transcription factors and several intracellular and extracellular signaling pathways including WNT/β-catenin signaling. This signaling pathway plays an essential role in multiple developmental processes and has a profound effect on cell proliferation and cell fate determination. During eye development, the activity of WNT/β-catenin signaling is tightly controlled. Faulty regulation of WNT/β-catenin signaling results in multiple ocular malformations due to defects in the process of cell fate determination and differentiation. This mini-review summarizes recent findings on the role of WNT/β-catenin signaling in eye development. Whilst this mini-review focuses on loss-of-function and gain-of-function mutants of WNT/β-catenin signaling components, it also highlights some important aspects of β-catenin-independent WNT signaling in the eye development at later stages.

• Klíčová slova
• WNT, development, differentiation, retina, β-catenin,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Primary cilia act as crucial regulators of embryo development and tissue homeostasis. They are instrumental for modulation of several signaling pathways, including Hedgehog, WNT, and TGF-β. However, gaps exist in our understanding of how cilia formation and function is regulated. Recent work has implicated WNT/β-catenin signaling pathway in the regulation of ciliogenesis, yet the results are conflicting. One model suggests that WNT/β-catenin signaling negatively regulates cilia formation, possibly via effects on cell cycle. In contrast, second model proposes a positive role of WNT/β-catenin signaling on cilia formation, mediated by the re-arrangement of centriolar satellites in response to phosphorylation of the key component of WNT/β-catenin pathway, β-catenin. To clarify these discrepancies, we investigated possible regulation of primary cilia by the WNT/β-catenin pathway in cell lines (RPE-1, NIH3T3, and HEK293) commonly used to study ciliogenesis. We used WNT3a to activate or LGK974 to block the pathway, and examined initiation of ciliogenesis, cilium length, and percentage of ciliated cells. We show that the treatment by WNT3a has no- or lesser inhibitory effect on cilia formation. Importantly, the inhibition of secretion of endogenous WNT ligands using LGK974 blocks WNT signaling but does not affect ciliogenesis. Finally, using knock-out cells for key WNT pathway components, namely DVL1/2/3, LRP5/6, or AXIN1/2 we show that neither activation nor deactivation of the WNT/β-catenin pathway affects the process of ciliogenesis. These results suggest that WNT/β-catenin-mediated signaling is not generally required for efficient cilia formation. In fact, activation of the WNT/β-catenin pathway in some systems seems to moderately suppress ciliogenesis.

• Klíčová slova
• HEK293, NIH3T3, RPE-1, Wnt/β-catenin, Wnt3a, cell signaling, ciliogenesis, primary cilia,
• Publikační typ
• časopisecké články MeSH

Deciphering the mechanisms of axis formation in amphioxus is a key step to understanding the evolution of chordate body plan. The current view is that Nodal signaling is the only factor promoting the dorsal axis specification in the amphioxus, whereas Wnt/β-catenin signaling plays no role in this process. Here, we re-examined the role of Wnt/βcatenin signaling in the dorsal/ventral patterning of amphioxus embryo. We demonstrated that the spatial activity of Wnt/β-catenin signaling is located in presumptive dorsal cells from cleavage to gastrula stage, and provided functional evidence that Wnt/β-catenin signaling is necessary for the specification of dorsal cell fate in a stage-dependent manner. Microinjection of Wnt8 and Wnt11 mRNA induced ectopic dorsal axis in neurulae and larvae. Finally, we demonstrated that Nodal and Wnt/β-catenin signaling cooperate to promote the dorsal-specific gene expression in amphioxus gastrula. Our study reveals high evolutionary conservation of dorsal organizer formation in the chordate lineage.

• Klíčová slova
• axial patterning, body plan, branchiostoma floridae, branchiostoma lanceolatum, developmental biology, evolution, evolutionary biology, wnt/β-catenin signaling,
• MeSH
• beta-katenin metabolismus   MeSH
• biologická evoluce MeSH
• HEK293 buňky MeSH
• kopinatci embryologie   metabolismus   MeSH
• lidé MeSH
• protein goosecoid metabolismus   MeSH
• protein nodal metabolismus   MeSH
• protein Smad2 metabolismus   MeSH
• signální dráha Wnt * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• beta-katenin MeSH
• protein goosecoid MeSH
• protein nodal MeSH
• protein Smad2 MeSH

Dishevelled (DVL) proteins are key mediators of the Wnt/β-catenin signaling pathway. All DVL proteins contain three conserved domains: DIX, PDZ, and DEP. There is a consensus in the field that the DIX domain is critical for Wnt/β-catenin signaling, but contradictory evidence regarding the function of the DEP domain exists. It has been difficult, until recently, to test the importance of the DEP domain rigorously because of the interference with endogenous DVL, expressed in all Wnt-responsive cell lines. In this study, we took advantage of DVL knockout (DVL1/DVL2/DVL3 triple knockout) cells fully deficient in Wnt3a-induced signaling events and performed a series of rescue experiments. Using these complementation assays, we analyzed the role of individual DVL isoforms. Further domain mapping of DVL1 showed that both the DVL1 DEP domain and especially its N-terminal region are required and sufficient for Wnt3a-induced phosphorylation of LRP6 and TopFlash reporter activation. On the contrary, multiple DEP domain mutants deficient in the planar cell polarity (PCP) pathway could fully rescue the Wnt3a response. This study provides conclusive evidence that the DVL DEP domain is essential for Wnt/β-catenin signaling in mammalian cells and establishes an experimental system suitable for further functional testing of DVL.

• Klíčová slova
• CRISPR/Cas, DEP domain, Dishevelled, Wnt/β-catenin signaling, Wnt3a,
• Publikační typ
• časopisecké články MeSH

Colorectal cancer (CRC) is the fourth leading cause of cancer mortality worldwide. Aberrant activation of WNT/β-catenin signaling present in the vast majority of CRC cases is indispensable for CRC initiation and progression, and thus is a promising target for CRC therapeutics. Hispolon is a fungal-derived polyphenol with a pronounced anticancer effect. Several hispolon derivatives, including dehydroxyhispolon methyl ether (DHME), have been chemically synthesized for developing lead molecules with stronger anticancer activity. Herein, a DHME-elicited anti-CRC effect with the underlying mechanism is reported for the first time. Specifically, DHME was found to be more cytotoxic than hispolon against a panel of human CRC cell lines, while exerting limited toxicity to normal human colon cell line CCD 841 CoN. Additionally, the cytotoxic effect of DHME appeared to rely on inducing apoptosis. This notion was evidenced by DHME-elicited upregulation of poly (ADP-ribose) polymerase (PARP) cleavage and a cell population positively stained by annexin V, alongside the downregulation of antiapoptotic B-cell lymphoma 2 (BCL-2), whereas the blockade of apoptosis by the pan-caspase inhibitor z-VAD-fmk attenuated DHME-induced cytotoxicity. Further mechanistic inquiry revealed the inhibitory action of DHME on β-catenin-mediated, T-cell factor (TCF)-dependent transcription activity, suggesting that DHME thwarted the aberrantly active WNT/β-catenin signaling in CRC cells. Notably, ectopic expression of a dominant-active β-catenin mutant (∆N90-β-catenin) abolished DHME-induced apoptosis while also restoring BCL-2 expression. Collectively, we identified DHME as a selective proapoptotic agent against CRC cells, exerting more potent cytotoxicity than hispolon, and provoking CRC cell apoptosis via suppression of the WNT/β-catenin signaling axis.

• Klíčová slova
• Phellinus linteus, WNT/β-catenin, colorectal cancer, dehydroxyhispolon methyl ether, hispolon, hispolon derivatives,
• MeSH
• antitumorózní látky farmakologie   MeSH
• apoptóza * MeSH
• Basidiomycota chemie   MeSH
• HCT116 buňky MeSH
• kolorektální nádory farmakoterapie   metabolismus   patofyziologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• poly(ADP-ribosa)-polymerasy metabolismus   MeSH
• protoonkogenní proteiny c-bcl-2 genetika   MeSH
• regulace genové exprese u nádorů MeSH
• signální dráha Wnt účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antitumorózní látky MeSH
• poly(ADP-ribosa)-polymerasy MeSH
• protoonkogenní proteiny c-bcl-2 MeSH

Coronary heart disease (CHD) is one of the most commonly seen cardiovascular conditions across the globe. Junctional cadherin 5 associated (JCAD) protein is found in the intercellular junctions of endothelial cells and linked to cardiovascular diseases. Nonetheless, the influence of JCAD on cardiomyocyte injury caused by CHD is unclear. A model of H2O2-induced H9c2 cell injury was constructed, and JCAD mRNA and protein levels were assessed by qRT-PCR and Western blot. The impacts of JCAD on the proliferation or apoptosis of H9c2 cells were explored by CCK-8 assay, Western blot and TUNEL staining. The effect of JCAD on the inflammatory response and vascular endothelial function of H9c2 cells was detected using ELISA kits. The levels of Wnt/β-catenin pathway-related proteins were assessed by Western blot. H2O2 treatment led to a rise in the levels of JCAD in H9c2 cells. Over-expression of JCAD promoted H2O2-induced cellular injury, leading to notably elevated contents of inflammatory factors, along with vascular endothelial dysfunction. In contrast to over-expression of JCAD, silencing of JCAD attenuated H2O2-induced cellular injury and inhibited apoptosis, inflammatory response and vascular endothelial dysfunction. Notably, JCAD could regulate the Wnt/β-catenin pathway, while DKK-1, Wnt/β-catenin pathway antagonist, counteracted the enhancing impact of JCAD over-expression on H2O2-induced H9c2 cell injury, further confirming that JCAD acts by regulating the Wnt/β-catenin pathway. In summary, over-expression of JCAD promoted H2O2-induced H9c2 cell injury by activating the Wnt/β-catenin pathway, while silencing of JCAD attenuated the H2O2-induced cell injury.

• Klíčová slova
• JCAD, Wnt/β-catenin signalling pathway, coronary heart disease, inflammation, vascular endothelial function,
• MeSH
• apoptóza * účinky léků   MeSH
• beta-katenin metabolismus   MeSH
• buněčné linie MeSH
• down regulace * účinky léků   MeSH
• kadheriny metabolismus   MeSH
• kardiomyocyty * metabolismus   účinky léků   MeSH
• krysa rodu Rattus MeSH
• peroxid vodíku * farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• signální dráha Wnt * účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta-katenin MeSH
• kadheriny MeSH
• peroxid vodíku * MeSH

BACKGROUND: The choroid plexus (ChP) is the secretory epithelial structure located in the brain ventricles. Choroid plexus tumors (CPTs) are rare neoplasms predominantly occurring in young patients with intensified malignancy in children. CPT treatment is hindered by insufficient knowledge of tumor pathology and the limited availability of valid models. METHODS: Genomic and transcriptomic data from CPT patients were analyzed to identify the putative pathological pathway. Cellular and molecular techniques were employed to validate bioinformatic results in CPT patient samples. Pharmacologic inhibition of Wnt/β-catenin signaling was assessed in CPT cells. Cell-based assays of ChP cell lines were performed following CRISPR-Cas9-derived knockout and overexpression of Wnt/β-catenin pathway genes. A 3D CPT model was generated through CRISPR-Cas9-derived knockout of APC. RESULTS: We discovered that Wnt/β-catenin signaling is activated in human CPTs, likely as a consequence of large-scale chromosomal instability events of the CPT genomes. We demonstrated that CPT-derived cells depend on autocrine Wnt/β-catenin signaling for survival. Constitutive Wnt/β-catenin pathway activation, either through knockout of the negative regulator APC or overexpression of the ligand WNT3A, induced tumorigenic properties in ChP 2D in vitro models. Increased activation of the Wnt/β-catenin pathway in ChP organoids, through treatment with a potent GSK3β inhibitor, reduced the differentiation of mature ChP epithelial cells. Remarkably, the depletion of APC was sufficient to induce the oncogenic transformation of ChP organoids. CONCLUSIONS: Our research identifies Wnt/β-catenin signaling as a critical driver of CPT tumorigenesis and provides the first 3D in vitro model for future pathological and therapeutic studies of CPT.

• Klíčová slova
• APC, Wnt signaling, brain tumor, choroid plexus organoid, rare childhood cancer,
• MeSH
• beta-katenin metabolismus   genetika   MeSH
• karcinogeneze metabolismus   MeSH
• lidé MeSH
• nádorové buňky kultivované MeSH
• nádory plexus chorioideus * patologie   metabolismus   genetika   MeSH
• plexus chorioideus metabolismus   patologie   MeSH
• proliferace buněk MeSH
• regulace genové exprese u nádorů MeSH
• signální dráha Wnt * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta-katenin MeSH
• CTNNB1 protein, human MeSH Prohlížeč

Activation of the Wnt/β-catenin pathway crucially depends on the polymerization of dishevelled 2 (DVL2) into biomolecular condensates. However, given the low affinity of known DVL2 self-interaction sites and its low cellular concentration, it is unclear how polymers can form. Here, we detect oligomeric DVL2 complexes at endogenous protein levels in human cell lines, using a biochemical ultracentrifugation assay. We identify a low-complexity region (LCR4) in the C-terminus whose deletion and fusion decreased and increased the complexes, respectively. Notably, LCR4-induced complexes correlated with the formation of microscopically visible multimeric condensates. Adjacent to LCR4, we mapped a conserved domain (CD2) promoting condensates only. Molecularly, LCR4 and CD2 mediated DVL2 self-interaction via aggregating residues and phenylalanine stickers, respectively. Point mutations inactivating these interaction sites impaired Wnt pathway activation by DVL2. Our study discovers DVL2 complexes with functional importance for Wnt/β-catenin signaling. Moreover, we provide evidence that DVL2 condensates form in two steps by pre-oligomerization via high-affinity interaction sites, such as LCR4, and subsequent condensation via low-affinity interaction sites, such as CD2.

• Klíčová slova
• DVL2, Wnt signaling, biochemistry, biomolecular condensates, cell biology, chemical biology, dishevelled, human, paralogs,
• MeSH
• beta-katenin metabolismus   genetika   MeSH
• HEK293 buňky MeSH
• lidé MeSH
• multimerizace proteinu MeSH
• protein dishevelled * metabolismus   genetika   MeSH
• signální dráha Wnt * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta-katenin MeSH
• DVL2 protein, human MeSH Prohlížeč
• protein dishevelled * MeSH

The lipoglycoproteins of the mammalian WNT family induce β-catenin-dependent signaling through interaction with members of the Class Frizzled receptors and LDL receptor-related protein 5/6 (LRP5/6) albeit with unknown selectivity. The 10 mammalian Frizzleds (FZDs) are seven transmembrane (7TM) spanning receptors and have recently been classified as G protein-coupled receptors (GPCRs). This review summarizes the current knowledge about WNT/FZD selectivity and functional selectivity, the role of co-receptors for signal specification, the formation of receptor complexes as well as the kinetics and mechanisms of signal initiation with focus on WNT/β-catenin signaling. In order to exploit the true therapeutic potential of WNT/FZD signaling to treat human disease, it is clear that substantial progress in the understanding of receptor complex formation and signal specification has to precede a mechanism-based drug design targeting WNT receptors.

• Klíčová slova
• Canonical signaling, Class Frizzled, GPCR, LRP5/6, Receptor complex,
• MeSH
• frizzled receptory chemie   metabolismus   MeSH
• kinetika MeSH
• lidé MeSH
• ligandy MeSH
• multimerizace proteinu MeSH
• signální dráha Wnt * MeSH
• substrátová specifita MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• frizzled receptory MeSH
• ligandy MeSH

β-catenin is a key integrator of cadherin-mediated cell-cell adhesion and transcriptional regulation through the Wnt/β-catenin pathway, which plays an important role in liver biology. Using a model of contact-inhibited liver progenitor cells, we examined the interactions of Wnt/β-catenin signaling with the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, which mediates the toxicity of dioxin-like compounds, including their effects on development and hepatocarcinogenesis. We found that AhR and Wnt/β-catenin cooperated in the induction of AhR transcriptional targets, such as Cyp1a1 and Cyp1b1. However, simultaneously, the activation of AhR led to a decrease of dephosphorylated active β-catenin pool, as well as to hypophosphorylation of Dishevelled, participating in regulation of Wnt signaling. A sustained AhR activation by its model ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), led to a downregulation of a number of Wnt/β-catenin pathway target genes. TCDD also induced a switch in cytokeratin expression, where downregulation of cytokeratins 14 and 19 was accompanied with an increased cytokeratin 8 expression. Together with a downregulation of additional markers associated with stem-like phenotype, this indicated that the AhR activation interfered with differentiation of liver progenitors. The downregulation of β-catenin was also related to a reduced cell adhesion, disruption of E-cadherin-mediated cell-cell junctions and an increased G1-S transition in liver progenitor cell line. In conclusion, although β-catenin augmented the expression of selected AhR target genes, the persistent AhR activation may lead to downregulation of Wnt/β-catenin signaling, thus altering differentiation and/or proliferative status of liver progenitor cells.

• MeSH
• aromatické hydroxylasy genetika   metabolismus   MeSH
• beta-katenin genetika   metabolismus   MeSH
• buněčná adheze MeSH
• buněčná diferenciace MeSH
• buněčné linie MeSH
• cytochrom P-450 CYP1A1 genetika   metabolismus   MeSH
• cytochrom P450 CYP1B1 MeSH
• down regulace účinky léků   MeSH
• hepatocyty účinky léků   MeSH
• játra účinky léků   MeSH
• kadheriny genetika   MeSH
• krysa rodu Rattus MeSH
• polychlorované dibenzodioxiny toxicita   MeSH
• potkani inbrední F344 MeSH
• proteiny Wnt genetika   metabolismus   MeSH
• receptory aromatických uhlovodíků genetika   metabolismus   MeSH
• signální dráha Wnt MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aromatické hydroxylasy MeSH
• beta-katenin MeSH
• Cyp1b1 protein, rat MeSH Prohlížeč
• cytochrom P-450 CYP1A1 MeSH
• cytochrom P450 CYP1B1 MeSH
• kadheriny MeSH
• polychlorované dibenzodioxiny MeSH
• proteiny Wnt MeSH
• receptory aromatických uhlovodíků MeSH