Primary cilia are key regulators of embryo development and tissue homeostasis. However, their mechanisms and functions, particularly in the context of human cells, are still unclear. Here, we analyzed the consequences of primary cilia modulation for human pluripotent stem cells (hPSCs) proliferation and differentiation. We report that neither activation of the cilia-associated Hedgehog signaling pathway nor ablation of primary cilia by CRISPR gene editing to knockout Tau Tubulin Kinase 2 (TTBK2), a crucial ciliogenesis regulator, affects the self-renewal of hPSCs. Further, we show that TTBK1, a related kinase without previous links to ciliogenesis, is upregulated during hPSCs-derived neural rosette differentiation. Importantly, we demonstrate that while TTBK1 fails to localize to the mother centriole, it regulates primary cilia formation in the differentiated, but not the undifferentiated hPSCs. Finally, we show that TTBK1/2 and primary cilia are implicated in the regulation of the size of hPSCs-derived neural rosettes.
- MeSH
- Centrioles metabolism MeSH
- Cilia metabolism MeSH
- Humans MeSH
- Pluripotent Stem Cells * metabolism MeSH
- Protein Serine-Threonine Kinases genetics metabolism MeSH
- Hedgehog Proteins * genetics metabolism MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The spermatozoon ultrastructure of the progenetic cestode Diplocotyle olrikii (Spathebothriidea) has been examined using transmission electron microscopy and cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate (PA-TSC-SP) for glycogen. The spermatozoon is a filiform cell, tapered at both extremities. Its moderately electron-dense cytoplasm possesses two parallel axonemes of unequal lengths. New for the Cestoda is a finding of three types of the mature spermatozoa with respect to different axonemal structure. The first type has both axonemes with standard 9 + '1' trepaxonematan pattern. The second type is represented by a spermatozoon having one axoneme with 9 + '1' structure and the second one with 9 + 0 pattern. The third type includes the two axonemes with 9 + 0 pattern. Microtubule doublets of the 9 + 0 axonemes contain either inner dynein arms or no dynein arms. In addition to the two axonemes, all three types of the mature sperm cells contain parallel nucleus, parallel cortical microtubules, four electron-dense plaques/attachment zones, and glycogen. The anterior extremity of the gamete exhibits a centriole surrounded by a semiarc of up to five electron-dense tubular structures. The distal end of the first type spermatozoa exhibits two morphological variants, represented either by (i) nucleus or (ii) remnants of the disorganized axoneme. Distal extremity of the spermatozoa of the second and third types contains doublets and singlets of disorganized axoneme. The ultrastructural characters of the spermatozoon of progenetic D. olrikii support the basal position of the Spathebothriidea within the Eucestoda.
- MeSH
- Axoneme ultrastructure MeSH
- Cell Nucleus ultrastructure MeSH
- Centrioles ultrastructure MeSH
- Cestoda ultrastructure MeSH
- Cytoplasm ultrastructure MeSH
- Spermatogenesis physiology MeSH
- Spermatozoa ultrastructure MeSH
- Microscopy, Electron, Transmission MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
NANOG is a transcription factor involved in the regulation of pluripotency and stemness. The functional paralog of NANOG, NANOGP8, differs from NANOG in only three amino acids and exhibits similar reprogramming activity. Given the transcriptional regulatory role played by NANOG, the nuclear localization of NANOG/NANOGP8 has primarily been considered to date. In this study, we investigated the intriguing extranuclear localization of NANOG and demonstrated that a substantial pool of NANOG/NANOGP8 is localized at the centrosome. Using double immunofluorescence, the colocalization of NANOG protein with pericentrin was identified by two independent anti-NANOG antibodies among 11 tumor and non-tumor cell lines. The validity of these observations was confirmed by transient expression of GFP-tagged NANOG, which also colocalized with pericentrin. Mass spectrometry of the anti-NANOG immunoprecipitated samples verified the antibody specificity and revealed the expression of both NANOG and NANOGP8, which was further confirmed by real-time PCR. Using cell fractionation, we show that a considerable amount of NANOG protein is present in the cytoplasm of RD and NTERA-2 cells. Importantly, cytoplasmic NANOG was unevenly distributed at the centrosome pair during the cell cycle and colocalized with the distal region of the mother centriole, and its presence was markedly associated with centriole maturation. Along with the finding that the centrosomal localization of NANOG/NANOGP8 was detected in various tumor and non-tumor cell types, these results provide the first evidence suggesting a common centrosome-specific role of NANOG.
The immune synapse (IS) is a temporary interface between an antigen-presenting cell and an effector lymphocyte. Viral synapse is a molecularly organized cellular junction that is structurally similar to the IS. Primary cilium is considered as a functional homologue of the IS due to the morphological and functional similarities in architecture between both micotubule structures. It has been hypothesized that endogenous electromagnetic field in the cell is generated by a unique cooperating system between mitochondria and microtubules. We are extending this prior hypothesis of the endogenous electromagnetic field in the cell postulating that polarized centriole in immune and viral synapse could serve as a monopole antenna. This is an addition to our hypothesis that primary cilium could serve as a monopole antenna. We simulated the distribution of electric field of centriole of polarized centrosome as a monopole antenna in immune and viral synapse. Very weak electromagnetic field of polarized centriole of CD8+ T lymphocyte in IS can contribute to the transport of cytolytic granules into the attacked (cancer) cell. Analogically, very weak electromagnetic field of polarized centriole in viral synapse of infected CD4 cells can aid the transport of viruses (human immunodeficiency virus) to non-infected CD4 cells. We hypothesized that healthy organisms need these monopole antennas. If, during the neoplastic transformation, healthy cells lose monopole antennas in form of primary cilia, the IS aims to replace them by monopole antennas of polarized centrioles in IS to restore homeostasis.
- MeSH
- CD8-Positive T-Lymphocytes immunology MeSH
- Centrioles genetics MeSH
- Centrosome immunology MeSH
- Electromagnetic Fields MeSH
- Immune System * MeSH
- Humans MeSH
- Microtubules genetics metabolism MeSH
- Neoplasms genetics immunology pathology MeSH
- Cell Polarity genetics immunology MeSH
- Synapses genetics virology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
This study was conducted to investigate Brachymystax lenok tsinlingensis spermatozoa cell morphology and ultrastructure through scanning and transmission electron microscopy. Findings revealed that the spermatozoa can be differentiated into three major parts: a spherical head without an acrosome, a short mid-piece, and a long, cylindrical flagellum. The mean length of the spermatozoa was 36.11±2.84μm, with a spherical head length of 2.78±0.31μm. The mean anterior and posterior head widths were 2.20±0.42μm and 2.55±0.53μm, respectively. The nuclear fossa was positioned at the base of the nucleus that contained the anterior portion of flagellum and a centriolar complex (proximal and distal centrioles). The short mid-piece was located laterally to the nucleus and possessed just one spherical mitochondrion with a mean diameter of 0.65±0.14μm. The spermatozoa flagellum was long and cylindrical, and could be separated into two parts: a long main-piece and a short end-piece. The main piece of the flagellum had short irregular side-fins. The axoneme composed the typical '9+2' microtubular doublet structure and was enclosed by the cell membran e. This study confirmed that B. lenok tsinlingensis spermatozoa can be categorized as teleostean "Type I" spermatozoa; 'primitive' or 'ect-aquasperm type' spermatozoa. To the best of the authers knowledge, this was the first study conducted on the morphology and ultrastructure of B. lenok tsinlingensis spermatozoa.
- MeSH
- Acrosome ultrastructure MeSH
- Axoneme ultrastructure MeSH
- Cell Nucleus ultrastructure MeSH
- Centrioles ultrastructure MeSH
- Flagella ultrastructure MeSH
- Microscopy, Electron, Scanning MeSH
- Mitochondria ultrastructure MeSH
- Salmonidae anatomy & histology growth & development MeSH
- Spermatozoa ultrastructure MeSH
- Microscopy, Electron, Transmission MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Tripolar mitosis is a specific case of cell division driven by typical molecular mechanisms of mitosis, but resulting in three daughter cells instead of the usual count of two. Other variants of multipolar mitosis show even more mitotic poles and are relatively rare. In nature, this phenomenon was frequently observed or suspected in multiple common cancers, infected cells, the placenta, and in early human embryos with impaired pregnancy-yielding potential. Artificial causes include radiation and various toxins. Here we combine several pieces of the most recent evidence for the existence of different types of multipolar mitosis in preimplantation embryos together with a detailed review of the literature. The related molecular and cellular mechanisms are discussed, including the regulation of centriole duplication, mitotic spindle biology, centromere functions, cell cycle checkpoints, mitotic autocorrection mechanisms, and the related complicating factors in healthy and affected cells, including post-mitotic cell-cell fusion often associated with multipolar cell division. Clinical relevance for oncology and embryo selection in assisted reproduction is also briefly discussed in this context.
- MeSH
- Blastocyst metabolism MeSH
- Centrioles metabolism MeSH
- Cell Cycle Checkpoints * MeSH
- Humans MeSH
- Neoplasms metabolism MeSH
- Placenta metabolism MeSH
- Pregnancy MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Pregnancy MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
Primární řasinka je senzorická buněčná organela, která se v klidové fázi buněčného cyklu vyskytuje u většiny lidských buněk, včetně buněk embryonálních, kmenových a buněk stromatu nádoru. Přítomnost primární řasinky na povrchu buňky je přechodná: vyskytuje se v klidové G1 (G0) fázi a na počátku S fáze buněčného cyklu. Bazálním tělískem primární řasinky je mateřská centriola. U většiny nádorových buněk se primární řasinka nevyskytuje. Výjimkou jsou nádory, které jsou závislé na signální dráze Hedgehog a tím i na primární řasince, jako například bazocelulární karcinom kůže či meduloblastom. Primární řasinka je pozorována i u trojitě negativního karcinomu prsu. V primárních řasinkách je přítomna řada receptorů, včetně mechanosenzorů, receptorů pro růstové faktory (EGFR, PDGFR), hormony (somatostatin), biologicky aktivní látky (serotonin) a morfogeny (Hedgehog, Wnt). V primární řasince se vyskytují signální dráhy Hedgehog a Wnt. U těch typů lidských buněk, které mají primární řasinku – tedy u naprosté většiny buněk, se signální dráhy Hedgehog a Wnt vyskytují výlučně právě jen v primární řasince. Cílem tohoto sdělení je přehled biologických funkcí primárních řasinek.
The primary cilium is a sensory organelle protruding in the quiescent phase of the cell cycle from the surface of the majority of human cells, including embryonic cells, stem cells and stromal cells of malignant tumors. The presence of primary cilium on the cell surface is transient, limited to the quiescent G1 (G0) phase, as well as the beginning of the S phase of the cell cycle. Primary cilium is formed from the centriole. Most cancer cells do not posses the primary cilium, with some exceptions, such as tumors depending on the Hedgehog pathway -e.g. basal cell carcinoma or medulloblastoma. The primary cilium is present also in cells of triple negative breast carcinoma. Primary cilia are equiped with a variety of receptors, including mechanosensors, receptors for growth factors (EGFR, PDGFR), hormones (somatostatin), biologically active substances (serotonin) and morphogens (Hedgehog, Wnt). Multiple components of Hedgehog and Wnt pathways are localized in the primary cilium. In the human cells possessing the primary cilium (majority of the human cells) Hedgehog and Wnt pathways are located exclusively in primary cilium. The aim of this paper is review of the current knowledge of the biological functions of the primary cilia.
- Keywords
- nádorové buňky, EGFR, PDGFR, Hedgehog, Wnt,
- MeSH
- Cell Cycle physiology MeSH
- Centrioles physiology MeSH
- Cilia physiology metabolism MeSH
- ErbB Receptors physiology MeSH
- Extracellular Space physiology MeSH
- Financing, Organized MeSH
- Cell Physiological Phenomena MeSH
- Humans MeSH
- Cell Transformation, Neoplastic MeSH
- Hedgehog Proteins physiology MeSH
- Wnt Proteins physiology MeSH
- Receptor, Platelet-Derived Growth Factor alpha physiology MeSH
- Signal Transduction physiology MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Review MeSH
[1st ed.] XIII, 232 s. : obr., tab., grafy ; 22 cm
- MeSH
- Cell Division MeSH
- Centrioles physiology MeSH
- Cytoskeleton physiology MeSH
- Microscopy, Electron MeSH
- Conspectus
- Biologické vědy
- NML Fields
- biologie
- MeSH
- Cell Division MeSH
- Cellular Structures cytology ultrastructure MeSH
- Centrioles * ultrastructure MeSH
- Cilia MeSH
- Microscopy, Electron MeSH
- Epithelium * ultrastructure MeSH
- Humans MeSH
- Microtomy MeSH
- Multivesicular Bodies ultrastructure MeSH
- Organelles MeSH
- Rats, Wistar MeSH
- Fallopian Tubes * ultrastructure MeSH
- Check Tag
- Humans MeSH
- Female MeSH
