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   patologie   MeSH
• lidé MeSH
• nádorové buňky kultivované MeSH
• nádory plexus chorioideus * patologie   metabolismus   genetika   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

The Hindbrain Choroid Plexus is a complex, cerebrospinal fluid-secreting tissue that projects into the 4th vertebrate brain ventricle. Despite its irreplaceability in the development and homeostasis of the entire central nervous system, the research of Hindbrain Choroid Plexus and other Choroid Plexuses has been neglected by neuroscientists for decades. One of the obstacles is the lack of tools that describe the complex shape of the Hindbrain Choroid Plexus in the context of brain ventricles. Here we introduce an effective tool, termed ChOP-CT, for the noninvasive, X-ray micro-computed tomography-based, three-dimensional visualization and subsequent quantitative spatial morphological analysis of developing mouse Hindbrain Choroid Plexus. ChOP-CT can reliably quantify Hindbrain Choroid Plexus volume, surface area, length, outgrowth angle, the proportion of the ventricular space occupied, asymmetries and general shape alterations in mouse embryos from embryonic day 13.5 onwards. We provide evidence that ChOP-CT is suitable for the unbiased evaluation and detection of the Hindbrain Choroid Plexus alterations within various mutant embryos. We believe, that thanks to its versatility, quantitative nature and the possibility of automation, ChOP-CT will facilitate the analysis of the Hindbrain Choroid Plexus in the mouse models. This will ultimately accelerate the screening of the candidate genes and mechanisms involved in the onset of various Hindbrain Choroid Plexus-related diseases.

• Klíčová slova
• 3D visualization, Hindbrain choroid plexus, Morphometrics, X-ray micro-computed tomography,
• MeSH
• mozek MeSH
• mozkové komory * MeSH
• myši MeSH
• plexus chorioideus * diagnostické zobrazování   MeSH
• rentgenová mikrotomografie MeSH
• rombencefalon diagnostické zobrazování   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The choroid plexus (ChP) is an extensively vascularized tissue that protrudes into the brain ventricular system of all vertebrates. This highly specialized structure, consisting of the polarized epithelial sheet and underlying stroma, serves a spectrum of functions within the central nervous system (CNS), most notably the production of cerebrospinal fluid (CSF). The epithelial cells of the ChP have the competence to tightly modulate the biomolecule composition of CSF, which acts as a milieu functionally connecting ChP with other brain structures. This review aims to eloquently summarize the current knowledge about the development of ChP. We describe the mechanisms that control its early specification from roof plate followed by the formation of proliferative regions-cortical hem and rhombic lips-feeding later development of ChP. Next, we summarized the current knowledge on the maturation of ChP and mechanisms that control its morphological and cellular diversity. Furthermore, we attempted to review the currently available battery of molecular markers and mouse strains available for the research of ChP, and identified some technological shortcomings that must be overcome to accelerate the ChP research field. Overall, the central principle of this review is to highlight ChP as an intriguing and surprisingly poorly known structure that is vital for the development and function of the whole CNS. We believe that our summary will increase the interest in further studies of ChP that aim to describe the molecular and cellular principles guiding the development and function of this tissue.

• Klíčová slova
• Cerebrospinal fluid (CSF), ChP epithelial cells, Choroid plexus (ChP), Cortical hem, Morphogenesis, Rhombic lips,
• MeSH
• centrální nervový systém * MeSH
• epitelové buňky MeSH
• mozek MeSH
• myši MeSH
• plexus chorioideus * fyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

RNF43 is an E3 ubiquitin ligase and known negative regulator of WNT/β-catenin signaling. We demonstrate that RNF43 is also a regulator of noncanonical WNT5A-induced signaling in human cells. Analysis of the RNF43 interactome using BioID and immunoprecipitation showed that RNF43 can interact with the core receptor complex components dedicated to the noncanonical Wnt pathway such as ROR1, ROR2, VANGL1, and VANGL2. RNF43 triggers VANGL2 ubiquitination and proteasomal degradation and clathrin-dependent internalization of ROR1 receptor and inhibits ROR2 activation. These activities of RNF43 are physiologically relevant and block pro-metastatic WNT5A signaling in melanoma. RNF43 inhibits responses to WNT5A, which results in the suppression of invasive properties of melanoma cells. Furthermore, RNF43 prevented WNT5A-assisted development of resistance to BRAF V600E and MEK inhibitors. Next, RNF43 acted as melanoma suppressor and improved response to targeted therapies in vivo. In line with these findings, RNF43 expression decreases during melanoma progression and RNF43-low patients have a worse prognosis. We conclude that RNF43 is a newly discovered negative regulator of WNT5A-mediated biological responses that desensitizes cells to WNT5A.

• Klíčová slova
• BRAF V600E, RNF43, ROR1, VANGL1, WNT5A, cancer biology, cell biology, human, melanoma, mouse,
• MeSH
• invazivní růst nádoru genetika   MeSH
• melanom * genetika   patologie   prevence a kontrola   MeSH
• myši inbrední NOD MeSH
• myši MeSH
• protein Wnt 5a genetika   metabolismus   MeSH
• signální transdukce * MeSH
• ubikvitinligasy genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• protein Wnt 5a MeSH
• RNF43 protein, human MeSH Prohlížeč
• ubikvitinligasy MeSH
• WNT5A protein, human MeSH Prohlížeč