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Primary cilia are dynamic compartments that regulate multiple aspects of cellular signaling. The production, maintenance, and function of cilia involve more than 1000 genes in mammals, and their mutations disrupt the ciliary signaling which manifests in a plethora of pathological conditions-the ciliopathies. Skeletal ciliopathies are genetic disorders affecting the development and homeostasis of the skeleton, and encompass a broad spectrum of pathologies ranging from isolated polydactyly to lethal syndromic dysplasias. The recent advances in forward genetics allowed for the identification of novel regulators of skeletogenesis, and revealed a growing list of ciliary proteins that are critical for signaling pathways implicated in bone physiology. Among these, a group of protein kinases involved in cilia assembly, maintenance, signaling, and disassembly has emerged. In this review, we summarize the functions of cilia kinases in skeletal development and disease, and discuss the available and upcoming treatment options.
- Klíčová slova
- cilia kinase, ciliopathy, endochondral bone formation, primary cilia, skeletal ciliopathy, skeletal dysplasia, skeletogenesis,
- MeSH
- cilie metabolismus MeSH
- ciliopatie * genetika patologie MeSH
- homeostáza MeSH
- polydaktylie * genetika MeSH
- proteiny genetika MeSH
- savci MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- proteiny MeSH
Primary cilium is a solitary organelle that emanates from the surface of most postmitotic mammalian cells and serves as a sensory organelle, transmitting the mechanical and chemical cues to the cell. Primary cilia are key coordinators of various signaling pathways during development and maintenance of tissue homeostasis. The emerging evidence implicates primary cilia function in tooth development. Primary cilia are located in the dental epithelium and mesenchyme at early stages of tooth development and later during cell differentiation and production of hard tissues. The cilia are present when interactions between both the epithelium and mesenchyme are required for normal morphogenesis. As the primary cilium coordinates several signaling pathways essential for odontogenesis, ciliary defects can interrupt the latter process. Genetic or experimental alterations of cilia function lead to various developmental defects, including supernumerary or missing teeth, enamel and dentin hypoplasia, or teeth crowding. Moreover, dental phenotypes are observed in ciliopathies, including Bardet-Biedl syndrome, Ellis-van Creveld syndrome, Weyers acrofacial dysostosis, cranioectodermal dysplasia, and oral-facial-digital syndrome, altogether demonstrating that primary cilia play a critical role in regulation of both the early odontogenesis and later differentiation of hard tissue-producing cells. Here, we summarize the current evidence for the localization of primary cilia in dental tissues and the impact of disrupted cilia signaling on tooth development in ciliopathies.
- Klíčová slova
- craniofacial anomalies, growth/development, mineralized tissue/development, odontoblast(s), oral pathology, signal transduction,
- MeSH
- buněčná diferenciace fyziologie MeSH
- cilie fyziologie MeSH
- lidé MeSH
- maxilofaciální vývoj fyziologie MeSH
- odontogeneze fyziologie MeSH
- signální transdukce fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Motile cilia, hairlike structures present on the cell surface, have a well-appreciated role in human physiology, including sweeping mucus, dirt and debris out of the respiratory tract. However, we are only beginning to understand the mechanisms governing cilia growth, maintenance and function. In this issue, Arora et al. reveal new details about the control of cilia growth. They identify a previously unrecognized connection between adenylate cyclase 6 (AC6), a cilia signaling mediator, and the autophagy-mediated regulation of motile cilia length via kinesin Kif19a, a regulator of cilia length. These findings provide new insights into motile cilia biology and may lead to novel ciliopathy treatments.
- MeSH
- adenylátcyklasy MeSH
- cilie * MeSH
- kineziny * genetika MeSH
- lidé MeSH
- mikrotubuly MeSH
- savci MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- komentáře MeSH
- práce podpořená grantem MeSH
- Názvy látek
- adenylátcyklasy MeSH
- adenylyl cyclase 6 MeSH Prohlížeč
- kineziny * MeSH
OBJECTIVES: Primary cilium is a cellular organelle with growing significance confirmed in tumour biology. Primary cilia have been associated with fine tuning of numerous cell signalling pathways and the role of this structure in cancer initiation and progression is recently at the forefront of attention. Here, we investigated possible alterations in the occurrence of primary cilia and changes of associated signalling in ameloblastoma, which represents the most common odontogenic tumour. METHODS: We performed immunohistochemistry to assess the number and morphology of primary cilia in ameloblastoma tissues. The gene expression of key SHH pathway members was analysed by qPCR. As a functional experiment, we treated a primary ameloblastoma cell line by a SHH pathway inhibitor Sonidegib (LDE225). RESULTS: We uncovered differences in primary cilia distribution and appearance in histological subtypes of ameloblastoma with the highest number of ciliated cells in plexiform and follicular subtypes. SHH protein was located close to primary cilia in ameloblastoma epithelial cells and the expression of molecules downstream of SHH signalling was upregulated. Moreover, the inhibition of SHH pathway by Sonidegib caused downregulation of SHH effector gene GLI1 and cell cycle regulator CCND1 in ameloblastoma primary cell line. The inhibition of SHH signalling also altered the expression of molecules involved in intraflagellar transport. CONCLUSIONS: In conclusion, our study uncovered alterations in number of ciliated cells and associated signalling in ameloblastoma, which indicate SHH inhibitors as potential therapeutic target to treat this disease.
- Klíčová slova
- Ameloblastoma, IFT, Primary cilia, SHH,
- MeSH
- ameloblastom * metabolismus MeSH
- cilie metabolismus MeSH
- lidé MeSH
- odontogenní nádory * metabolismus MeSH
- proteiny hedgehog metabolismus MeSH
- signální transdukce MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- proteiny hedgehog MeSH
BACKGROUND: Primary cilia facilitate cellular signalling and play critical roles in development, homeostasis, and disease. Their assembly is under the control of Tau-Tubulin Kinase 2 (TTBK2), a key enzyme mutated in patients with spinocerebellar ataxia. Recent work has implicated TTBK2 in the regulation of cilia maintenance and function, but the underlying molecular mechanisms are not understood. METHODS: To dissect the role of TTBK2 during cilia growth and maintenance in human cells, we examined disease-related TTBK2 truncations. We used biochemical approaches, proteomics, genetic engineering, and advanced microscopy techniques to unveil molecular events triggered by TTBK2. RESULTS: We demonstrate that truncated TTBK2 protein moieties, unable to localize to the mother centriole, create unique semi-permissive conditions for cilia assembly, under which cilia begin to form but fail to elongate. Subsequently, we link the defects in cilia growth to aberrant turnover of a microtubule-depolymerizing kinesin KIF2A, which we find restrained by TTBK2 phosphorylation. CONCLUSIONS: Together, our data imply that the regulation of KIF2A by TTBK2 represents an important mechanism governing cilia elongation and maintenance. Further, the requirement for concentrating TTBK2 activity to the mother centriole to initiate ciliogenesis can be under specific conditions bypassed, revealing TTBK2 recruitment-independent functions of its key partner, CEP164.
- Klíčová slova
- Basal body, Cilia, Ciliogenesis, KIF2A, TTBK2,
- MeSH
- centrioly metabolismus MeSH
- cilie * metabolismus MeSH
- fosforylace MeSH
- kineziny * metabolismus genetika MeSH
- lidé MeSH
- mikrotubuly * metabolismus MeSH
- protein-serin-threoninkinasy * metabolismus genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- KIF2A protein, human MeSH Prohlížeč
- kineziny * MeSH
- protein-serin-threoninkinasy * MeSH
- tau-tubulin kinase MeSH Prohlížeč
A single primary cilium projects from most vertebrate cells to guide cell fate decisions. A growing list of signaling molecules is found to function through cilia and control ciliogenesis, including the fibroblast growth factor receptors (FGFR). Aberrant FGFR activity produces abnormal cilia with deregulated signaling, which contributes to pathogenesis of the FGFR-mediated genetic disorders. FGFR lesions are also found in cancer, raising a possibility of cilia involvement in the neoplastic transformation and tumor progression. Here, we focus on FGFR gene fusions, and discuss the possible mechanisms by which they function as oncogenic drivers. We show that a substantial portion of the FGFR fusion partners are proteins associated with the centrosome cycle, including organization of the mitotic spindle and ciliogenesis. The functions of centrosome proteins are often lost with the gene fusion, leading to haploinsufficiency that induces cilia loss and deregulated cell division. We speculate that this complements the ectopic FGFR activity and drives the FGFR fusion cancers.
- Klíčová slova
- FGFR, FGFR fusion, cancer, centrosome, centrosome cycle, cilia, fibroblast growth factor receptor, neoplastic transformation, oncogenic driver, primary cilia,
- MeSH
- centrozom metabolismus MeSH
- cilie * metabolismus patologie MeSH
- lidé MeSH
- nádorová transformace buněk patologie MeSH
- nádory * metabolismus patologie MeSH
- onkogenní fúze MeSH
- receptory fibroblastových růstových faktorů metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- receptory fibroblastových růstových faktorů MeSH
Primary cilia are dynamically regulated during cell cycle progression, specifically during the G0/G1 phases of the cell cycle, being resorbed prior to mitosis. Primary cilia can be visualized with highly sophisticated methods, including transmission electron microscopy, 3D imaging, or using software for the automatic detection of primary cilia. However, immunofluorescent staining of primary cilia is needed to perform these methods. This publication describes a protocol for the easy detection of primary cilia in vitro by staining acetylated alpha tubulin (axoneme) and gamma tubulin (basal body). This immunofluorescent staining protocol is relatively simple and results in high-quality images. The present protocol describes how four cell lines (C2C12, MEF, NHLF, and skin fibroblasts) expressing primary cilia were fixed, immunostained, and imaged with a fluorescent or confocal microscope.
The primary cilium is considered as a key component of morphological cellular stability. However, cancer cells are notorious for lacking primary cilia in most cases, depending upon the tumour type. Previous reports have shown the effect of starvation and cytostatics on ciliogenesis in normal and cancer cells although with limited success, especially when concerning the latter. In this study, we evaluated the presence and frequency of primary cilia in breast fibroblasts and in triple-negative breast cancer cells after treatment with cytostatics finding that, in the case of breast fibroblasts, primary cilia were detected at their highest incidence 72 hours after treatment with 120 nM doxorubicin. Further, multiciliated cells were also detected after treatment with 80 nM doxorubicin. On the other hand, treatment with taxol increased the number of ciliated cells only at low concentrations (1.25 and 3.25 nM) and did not induce multiciliation. Interestingly, triple-negative breast cancer cells did not present primary cilia after treatment with either doxorubicin or taxol. This is the first study reporting the presence of multiple primary cilia in breast fibroblasts induced by doxorubicin. However, the null effect of these cytostatics on primary cilia incidence in the evaluated triple negative breast carcinomas cell lines requires further research.
- Klíčová slova
- doxorubicin, multiple cilia, primary cilium, triple-negative breast cancer,
- MeSH
- cilie účinky léků metabolismus MeSH
- cytostatické látky toxicita MeSH
- doxorubicin farmakologie MeSH
- fibroblasty účinky léků metabolismus MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- paclitaxel farmakologie MeSH
- proliferace buněk účinky léků MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cytostatické látky MeSH
- doxorubicin MeSH
- paclitaxel MeSH
Centrioles are highly elaborate microtubule-based structures responsible for the formation of centrosomes and cilia. Despite considerable variation across species and tissues within any given tissue, their size is essentially constant [1, 2]. While the diameter of the centriole cylinder is set by the dimensions of the inner scaffolding structure of the cartwheel [3], how centriole length is set so precisely and stably maintained over many cell divisions is not well understood. Cep97 and CP110 are conserved proteins that localize to the distal end of centrioles and have been reported to limit centriole elongation in vertebrates [4, 5]. Here, we examine Cep97 function in Drosophila melanogaster. We show that Cep97 is essential for formation of full-length centrioles in multiple tissues of the fly. We further identify the microtubule deacetylase Sirt2 as a Cep97 interactor. Deletion of Sirt2 likewise affects centriole size. Interestingly, so does deletion of the acetylase Atat1, indicating that loss of stabilizing acetyl marks impairs centriole integrity. Cep97 and CP110 were originally identified as inhibitors of cilia formation in vertebrate cultured cells [6], and loss of CP110 is a widely used marker of basal body maturation. In contrast, in Drosophila, Cep97 appears to be only transiently removed from basal bodies and loss of Cep97 strongly impairs ciliogenesis. Collectively, our results support a model whereby Cep97 functions as part of a protective cap that acts together with the microtubule acetylation machinery to maintain centriole stability, essential for proper function in cilium biogenesis.
- Klíčová slova
- Drosophila melanogaster, centrioles, cilia, organelle biogenesis,
- MeSH
- bazální tělíska metabolismus MeSH
- centrioly fyziologie MeSH
- centrozom * metabolismus MeSH
- cilie * genetika MeSH
- Drosophila melanogaster embryologie genetika MeSH
- kultivované buňky MeSH
- morfogeneze genetika fyziologie MeSH
- proteiny asociované s mikrotubuly metabolismus fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- proteiny asociované s mikrotubuly MeSH
Ectopic cilia are extremely rare congenital anomalies in which eyelash follicles appear in an abnormal place on the eyelid, most typically on the lateral quadrant of the anterior surface of the upper eyelid. In the majority of cases, simple surgical excision of ectopic cilia is indicated because of its cosmetic aspect. There is usually no associated medical co-morbidity with this anomaly. The authors report an unusual case of ectopic cilia associated with an orbital dermoid cyst and sinus tract. A 3-year-old boy was initially diagnosed with ectopic cilia on the left upper eyelid. There was no history of inflammation or swelling of the eyelid. An ophthalmological examination revealed only 1 mm of ptosis; no proptosis, inferior displacement, or palpable orbital mass was present. During surgical excision of the ectopic cilia, a thin sinus tract was identified, leading posteriorly to the orbit. Magnetic resonance imaging performed after the excision showed a supraorbital extraconal mass just below the roof of the left orbit. A supraorbital 2-piece craniotomy was performed with total extirpation of the dermoid cyst. The cyst was removed en bloc without damage to the extraocular muscles, but the sinus tract could no longer be identified. Follow-up MRI was performed 6 months after surgery and showed no evidence of recurrence. A follow-up ophthalmological examination showed no signs of inferior displacement or proptosis. To the best of the authors' knowledge, this case is the first reported instance of ectopic cilia associated with a dermoid cyst and sinus tract in which no typical clinical signs and symptoms of possible orbital pathology were present. This case highlights the value of radiological examination in all cases of ectopic cilia prior to surgical excision.
- Klíčová slova
- congenital, dermoid cyst, ectopic cilia, orbit, sinus tract,
- MeSH
- choristom komplikace chirurgie MeSH
- cilie * MeSH
- dermoidní cysta diagnóza chirurgie MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- nádory orbity komplikace diagnóza chirurgie MeSH
- píštěle komplikace chirurgie MeSH
- předškolní dítě MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- předškolní dítě MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH