Glioblastomas are aggressive brain tumors for which effective therapy is still lacking, resulting in dismal survival rates. These tumors display significant phenotypic plasticity, harboring diverse cell populations ranging from tumor core cells to dispersed, highly invasive cells. Neuron navigator 3 (NAV3), a microtubule-associated protein affecting microtubule growth and dynamics, is downregulated in various cancers, including glioblastoma, and has thus been considered a tumor suppressor. In this study, we challenge this designation and unveil distinct expression patterns of NAV3 across different invasion phenotypes. Using glioblastoma cell lines and patient-derived glioma stem-like cell cultures, we disclose an upregulation of NAV3 in invading glioblastoma cells, contrasting with its lower expression in cells residing in tumor spheroid cores. Furthermore, we establish an association between low and high NAV3 expression and the amoeboid and mesenchymal invasive phenotype, respectively, and demonstrate that overexpression of NAV3 directly stimulates glioblastoma invasive behavior in both 2D and 3D environments. Consistently, we observed increased NAV3 expression in cells migrating along blood vessels in mouse xenografts. Overall, our results shed light on the role of NAV3 in glioblastoma invasion, providing insights into this lethal aspect of glioblastoma behavior.
- MeSH
- Phenotype * MeSH
- Glioblastoma * pathology genetics metabolism MeSH
- Neoplasm Invasiveness * genetics MeSH
- Humans MeSH
- Membrane Proteins MeSH
- Microtubules metabolism MeSH
- Mice MeSH
- Cell Line, Tumor MeSH
- Brain Neoplasms * pathology genetics metabolism MeSH
- Cell Movement genetics physiology MeSH
- Nerve Tissue Proteins metabolism genetics MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Developmental remodeling shapes neural circuits via activity-dependent pruning of synapses and axons. Regulation of the cytoskeleton is critical for this process, as microtubule loss via enzymatic severing is an early step of pruning across many circuits and species. However, how microtubule-severing enzymes, such as spastin, are activated in specific neuronal compartments remains unknown. Here, we reveal that polyglutamylation, a post-translational tubulin modification enriched in neurons, plays an instructive role in developmental remodeling by tagging microtubules for severing. Motor neuron-specific gene deletion of enzymes that add or remove tubulin polyglutamylation-TTLL glutamylases vs. CCP deglutamylases-accelerates or delays neuromuscular synapse remodeling in a neurotransmission-dependent manner. This mechanism is not specific to peripheral synapses but also operates in central circuits, e.g., the hippocampus. Thus, tubulin polyglutamylation acts as a cytoskeletal rheostat of remodeling that shapes neuronal morphology and connectivity.
- MeSH
- Hippocampus metabolism cytology MeSH
- Polyglutamic Acid * metabolism MeSH
- Microtubules * metabolism MeSH
- Motor Neurons * metabolism MeSH
- Mice MeSH
- Neuromuscular Junction metabolism MeSH
- Synaptic Transmission MeSH
- Neurons * metabolism MeSH
- Neuronal Plasticity * physiology MeSH
- Peptide Synthases metabolism genetics MeSH
- Protein Processing, Post-Translational MeSH
- Spastin metabolism MeSH
- Synapses metabolism MeSH
- Tubulin metabolism MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
There is increasing pressure on meat producers worldwide due to the need for higher yields and improved meat quality. This is why anabolic androgenic steroids (AAS) have been widely used in most countries, due to their ability to accelerate animal muscle growth. However, out of concern for their side effects, EU states have banned their use and implemented control mechanisms. But they are reaching their limits, and therefore, it is necessary to look for new ways and investigate the mechanism of action of AAS on muscle tissue. This study replicated the administration of banned AAS (testosterone, nandrolone and their combination) and observed their effect on pig muscle. The pig model was purposely chosen for the study, as no such research has been carried out on this species. At the same time, pork is one of the most consumed meats in Europe. It focused on histological changes in muscle structure, specifically the size of muscle fibres and the number of satellite cells per muscle fibre. Furthermore, ultrastructural changes in muscle fibres, the diameter of myofibrils, the number of myofibrils per area, the distance between myofibrils and the size of sarcomeres were examined. The results using the techniques of histology, fluorescent labelling and transmission electron microscopy showed that, after the application of AAS, there is an increase in the diameter of muscle fibres, an increase in the diameter of myofibrils, a decrease in the number of myofibrils per surface area and, in the case of testosterone, an increase in the distance between myofibrils and an increase in the length of sarcomeres. There was also a significant increase in the number of satellite cells per muscle fibre. The detected statistically significant differences between control and experimental groups provide evidence that selected histological parameters could be additional mechanisms for detecting the presence of AAS in pork meat in the future.
- MeSH
- Anabolic Agents * pharmacology MeSH
- Muscle Fibers, Skeletal * drug effects ultrastructure MeSH
- Muscle, Skeletal drug effects anatomy & histology ultrastructure MeSH
- Myofibrils * drug effects ultrastructure MeSH
- Nandrolone * pharmacology MeSH
- Swine anatomy & histology MeSH
- Sarcomeres drug effects ultrastructure MeSH
- Satellite Cells, Skeletal Muscle drug effects ultrastructure MeSH
- Testosterone * pharmacology MeSH
- Microscopy, Electron, Transmission veterinary MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
PURPOSE: To document the expression of apical-basal polarity (ABP) determinants in the mouse corneal epithelium (CE) and elucidate the functions of Pard3 in establishment and maintenance of ABP, stratification, homeostasis, and barrier function in the CE. METHODS: Pard3Δ/ΔC mice (Pard3LoxP/LoxP; Aldh3A1-Cre/+) with cornea-specific Pard3 ablation were generated by breeding Aldh3A1-Cre/+ with Pard3LoxP/LoxP mice. The control (Aldh3A1-Cre/+ or Pard3LoxP/LoxP alone) and Pard3Δ/ΔC corneal histology, ocular surface properties, barrier function, and actin cytoskeleton were assessed by Haematoxylin and Eosin staining of paraformaldehyde-fixed, paraffin-embedded tissues, scanning electron microscopy, fluorescein staining, and phalloidin staining, respectively. The expression of specific markers of interest was evaluated by qRT-PCR, immunoblots and immunofluorescent staining. RESULTS: Dynamic changes were observed in the expression and localization of ABP determinants as the CE stratified and matured between post-natal day 5 (PN5) and PN52. Adult Pard3Δ/ΔC CE contained fewer cell layers with rounded basal cells, and loosely adherent superficial cells lacking microplicae. Adult Pard3Δ/ΔC CE also displayed impaired barrier function with decreased expression of tight junction, adherens junction, and desmosome components, disrupted actin cytoskeletal organization, increased proliferation, and upregulation of transcription factors that drive epithelial-mesenchymal transition (EMT). CONCLUSIONS: Disruption of ABP in Pard3Δ/ΔC CE, altered expression of cell junction complex components and disorganized actin cytoskeleton, increased cell proliferation, and upregulated EMT transcription factors suggest that the ABP-determinant Pard3 promotes CE features while suppressing mesenchymal cell fate. Collectively, these results elucidate that Pard3-mediated ABP is essential for CE stratification, homeostasis and barrier function.
- MeSH
- Adaptor Proteins, Signal Transducing * MeSH
- Cytoskeleton * metabolism MeSH
- Homeostasis physiology MeSH
- Microscopy, Electron, Scanning MeSH
- Mice MeSH
- Cell Polarity * physiology MeSH
- Epithelium, Corneal * metabolism ultrastructure MeSH
- Tight Junctions * metabolism physiology MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Neurons rely on the microtubule cytoskeleton to create and maintain their sophisticated cellular architectures. Advances in cryogenic electron microscopy, expansion microscopy, live imaging, and gene editing have enabled novel insights into mechanisms of centrosomal and acentrosomal microtubule nucleation, the key process generating new microtubules. This has paved the way for the functional dissection of distinct microtubule networks that regulate various processes during neuronal development, including neuronal delamination, polarization, migration, maturation, and synapse function. We review recent progress in understanding the molecular concepts of microtubule nucleation, how these concepts underlie neurodevelopmental processes, and pinpoint the open questions. Since microtubules play a pivotal role in axon regeneration within the adult central nervous system, understanding the processes of microtubule nucleation could inform strategies to enhance the regenerative capabilities of neurons in the future.
- MeSH
- Centrosome * metabolism physiology MeSH
- Humans MeSH
- Microtubules * metabolism physiology MeSH
- Neurogenesis * physiology MeSH
- Neurons * physiology metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
A20/Tnfaip3, an early NF-κB response gene and key negative regulator of NF-κB signaling, suppresses proinflammatory responses. Its ubiquitinase and deubiquitinase activities mediate proteasomal degradation within the NF-κB pathway. This study investigated the involvement of A20 signaling alterations in podocytes in the development of kidney injury. The phenotypes of A20Δpodocyte (podocyte-specific knockout of A20) mice were compared with those of control mice at 6 months of age to identify spontaneous changes in kidney function. A20Δpodocyte mice presented elevated serum urea nitrogen and creatinine levels, along with increased accumulation of inflammatory cells-neutrophils and macrophages-within the glomeruli. Additionally, A20Δpodocyte mice displayed significant podocyte loss. Ultrastructural analysis of A20 podocyte-knockout mouse glomeruli revealed hypocellularity of the glomerular tuft, expansion of the extracellular matrix, podocytopenia associated with foot process effacement, karyopyknosis, micronuclei, and podocyte detachment. In addition to podocyte death, we also observed damage to intracapillary endothelial cells with vacuolation of the cytoplasm and condensation of nuclear chromatin. A20 expression downregulation and CRISPR-Cas9 genome editing targeting A20 in a podocyte cell line confirmed these findings in vitro, highlighting the significant contribution of A20 activity in podocytes to glomerular injury pathogenesis. Finally, we analyzed TNFAIP3 transcription levels alongside genes involved in apoptosis, anoikis, NF-κB regulation, and cell attachment in glomerular and tubular compartments of kidney biopsies of patients with various renal diseases.
- MeSH
- Cytoskeleton * metabolism MeSH
- Glomerulonephritis * pathology metabolism genetics MeSH
- Kidney Glomerulus pathology metabolism MeSH
- Humans MeSH
- Mice, Inbred C57BL MeSH
- Mice, Knockout * MeSH
- Mice MeSH
- NF-kappa B metabolism MeSH
- Podocytes * metabolism pathology MeSH
- Signal Transduction MeSH
- Tumor Necrosis Factor alpha-Induced Protein 3 * metabolism genetics MeSH
- Inflammation * pathology genetics MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Anaplastic Large Cell Lymphoma (ALCL) is an aggressive T-cell lymphoma affecting children and young adults. About 30% of patients develop therapy resistance therefore new precision medicine drugs are highly warranted. Multiple rounds of structure-activity optimization of Caffeic Acid Phenethyl Ester have resulted in CM14. CM14 causes upregulation of genes involved in oxidative stress response and downregulation of DNA replication genes leading to G2/M arrest and subsequent apoptosis induction. In accordance with this, an unbiased proteomics approach, confocal microscopy and molecular modeling showed that TUBGCP2, member of the centrosomal γ-TuRC complex, is a direct interaction partner of CM14. CM14 overcomes ALK inhibitor resistance in ALCL and is also active in T-cell Acute Lymphoblastic Leukemia and Acute Myeloid Leukemia. Interestingly, CM14 also induced cell death in docetaxel-resistant prostate cancer cells thus suggesting an unexpected role in solid cancers. Thus, we synthesized and thoroughly characterized a novel TUBGCP2 targeting drug that is active in ALCL but has also potential for other malignancies.
- MeSH
- Apoptosis * drug effects MeSH
- Centrosome * drug effects metabolism MeSH
- Phenylethyl Alcohol * analogs & derivatives pharmacology chemistry MeSH
- Caffeic Acids * pharmacology chemistry MeSH
- Humans MeSH
- Cell Line, Tumor MeSH
- Cell Proliferation drug effects MeSH
- Antineoplastic Agents * pharmacology chemistry MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
MICAL proteins play a crucial role in cellular dynamics by binding and disassembling actin filaments, impacting processes like axon guidance, cytokinesis, and cell morphology. Their cellular activity is tightly controlled, as dysregulation can lead to detrimental effects on cellular morphology. Although previous studies have suggested that MICALs are autoinhibited, and require Rab proteins to become active, the detailed molecular mechanisms remained unclear. Here, we report the cryo-EM structure of human MICAL1 at a nominal resolution of 3.1 Å. Structural analyses, alongside biochemical and functional studies, show that MICAL1 autoinhibition is mediated by an intramolecular interaction between its N-terminal catalytic and C-terminal coiled-coil domains, blocking F-actin interaction. Moreover, we demonstrate that allosteric changes in the coiled-coil domain and the binding of the tripartite assembly of CH-L2α1-LIM domains to the coiled-coil domain are crucial for MICAL activation and autoinhibition. These mechanisms appear to be evolutionarily conserved, suggesting a potential universality across the MICAL family.
- MeSH
- Actins metabolism chemistry MeSH
- Allosteric Regulation MeSH
- Calponins MeSH
- Cryoelectron Microscopy * MeSH
- Humans MeSH
- Actin Cytoskeleton metabolism ultrastructure MeSH
- Microfilament Proteins metabolism chemistry ultrastructure MeSH
- Models, Molecular MeSH
- Mixed Function Oxygenases MeSH
- Protein Domains MeSH
- LIM Domain Proteins metabolism chemistry genetics MeSH
- Protein Binding * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
The first embryonic division represents a starting point for the development of a new individual. In many species, tight control over the first embryonic division ensures its accuracy. However, the first division in humans is often erroneous and can impair embryo development. To delineate the spatiotemporal organization of the first mitotic division typical for normal human embryo development, we systematically analyzed a unique timelapse dataset of 300 IVF embryos that developed into healthy newborns. The zygotic division pattern of these best-quality embryos was compared to their siblings that failed to implant or arrested during cleavage stage. We show that division at the right angle to the juxtaposed pronuclei is preferential and supports faithful zygotic division. Alternative configurations of the first mitosis are associated with reduced clustering of nucleoli and multinucleation at the 2-cell stage, which are more common in women of advanced age. Collectively, these data imply that orientation of the first division predisposes human embryos to genetic (in)stability and may contribute to aneuploidy and age-related infertility.
- MeSH
- Spindle Apparatus * metabolism MeSH
- Cell Nucleus * metabolism MeSH
- Embryo, Mammalian cytology MeSH
- Embryonic Development * MeSH
- Fertilization in Vitro MeSH
- Humans MeSH
- Mitosis * MeSH
- Cleavage Stage, Ovum cytology MeSH
- Zygote * metabolism cytology MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Transition fibres and distal appendages surround the distal end of mature basal bodies and are essential for ciliogenesis, but only a few of the proteins involved have been identified and functionally characterised. Here, through genome-wide analysis, we have identified 30 transition fibre proteins (TFPs) and mapped their arrangement in the flagellated eukaryote Trypanosoma brucei. We discovered that TFPs are recruited to the mature basal body before and after basal body duplication, with differential expression of five TFPs observed at the assembling new flagellum compared to the existing fixed-length old flagellum. RNAi-mediated depletion of 17 TFPs revealed six TFPs that are necessary for ciliogenesis and a further three TFPs that are necessary for normal flagellum length. We identified nine TFPs that had a detectable orthologue in at least one basal body-forming eukaryotic organism outside of the kinetoplastid parasites. Our work has tripled the number of known transition fibre components, demonstrating that transition fibres are complex and dynamic in their composition throughout the cell cycle, which relates to their essential roles in ciliogenesis and flagellum length regulation.
- MeSH
- Basal Bodies metabolism MeSH
- Time Factors MeSH
- Cilia genetics metabolism MeSH
- Flagella genetics metabolism MeSH
- Conserved Sequence MeSH
- Protozoan Proteins * genetics metabolism MeSH
- Gene Expression Regulation MeSH
- Protein Transport MeSH
- Trypanosoma brucei brucei * genetics metabolism MeSH
- Publication type
- Journal Article MeSH
