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European Journal of Pharmacology Jul 2024Osteoporosis is the most common bone disorder, in which an imbalance between osteoclastic bone resorption and osteoblastic bone formation disrupts bone homeostasis....
Osteoporosis is the most common bone disorder, in which an imbalance between osteoclastic bone resorption and osteoblastic bone formation disrupts bone homeostasis. Osteoporosis management using anti-osteoclastic agents is a promising strategy; however, this remains an unmet need. Sphingosine-1-phosphate (S1P) and its receptors (S1PRs) are essential for maintaining bone homeostasis. Here, we identified that Siponimod, a Food and Drug Administration-approved S1PR antagonist for the treatment of multiple sclerosis, shows promising therapeutic effects against osteoporosis by inhibiting osteoclast formation and function. We found that Siponimod inhibited osteoclast formation in a dose-dependent manner without causing cytotoxicity. Podosome belt staining and bone resorption assays indicated that Siponimod treatment impaired osteoclast function. Western blot and qPCR assays demonstrated that Siponimod suppressed the expression of osteoclast-specific markers, including C-Fos, Nftac1, and Ctsk. Mechanistically, we validated that Siponimod downregulated receptor activator of nuclear factor kappa B ligand (RANKL)-induced Mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB) signaling pathways during osteoclastogenesis. Moreover, in a preclinical mouse model, Siponimod prevented ovariectomy-induced bone loss by suppressing osteoclast activity in vivo. Collectively, these results suggest that Siponimod could serve as an alternative therapeutic agent for the treatment of osteoporosis.
Topics: Animals; Mice; Osteoporosis; Osteoclasts; Drug Repositioning; Benzyl Compounds; Azetidines; Multiple Sclerosis; Female; Sphingosine 1 Phosphate Receptor Modulators; Osteogenesis; NF-kappa B; Mice, Inbred C57BL; RAW 264.7 Cells; Bone Resorption; Signal Transduction; RANK Ligand; Humans
PubMed: 38692426
DOI: 10.1016/j.ejphar.2024.176630 -
International Journal of Molecular... Sep 2020Osteoclast signatures are determined by two transcriptional programs, the lineage-determining transcription pathway and the receptor activator of nuclear factor kappa-B... (Review)
Review
Osteoclast signatures are determined by two transcriptional programs, the lineage-determining transcription pathway and the receptor activator of nuclear factor kappa-B ligand (RANKL)-dependent differentiation pathways. During differentiation, mononuclear precursors become multinucleated by cell fusion. Recently, live-cell imaging has revealed a high level of heterogeneity in osteoclast multinucleation. This heterogeneity includes the difference in the differentiation states and the mobility of the fusion precursors, as well as the mode of fusion among the fusion precursors with different numbers of nuclei. In particular, fusion partners often form morphologically distinct actin-based linkages that allow two cells to exchange lipids and proteins before membrane fusion. However, the origin of this heterogeneity remains elusive. On the other hand, osteoclast multinucleation is sensitive to the environmental cues. Such cues promote the reorganization of the actin cytoskeleton, especially the formation and transformation of the podosome, an actin-rich punctate adhesion. This review covers the heterogeneity of osteoclast multinucleation at the pre-fusion stage with reference to the environment-dependent signaling pathway responsible for reorganizing the actin cytoskeleton. Furthermore, we compare osteoclast multinucleation with macrophage fusion, which results in multinucleated giant macrophages.
Topics: Actin Cytoskeleton; Animals; Cell Nucleus; Humans; Osteoclasts; Phagocytes
PubMed: 32927783
DOI: 10.3390/ijms21186629 -
Cell & Bioscience May 2023Tau protein forms neurofibrillary tangles and becomes deposited in the brain during Alzheimer's disease (AD). Tau oligomers are the most reactive species, mediating...
BACKGROUND
Tau protein forms neurofibrillary tangles and becomes deposited in the brain during Alzheimer's disease (AD). Tau oligomers are the most reactive species, mediating neurotoxic and inflammatory activity. Microglia are the immune cells in the central nervous system, sense the extracellular Tau via various cell surface receptors. Purinergic P2Y12 receptor can directly interact with Tau oligomers and mediates microglial chemotaxis via actin remodeling. The disease-associated microglia are associated with impaired migration and express a reduced level of P2Y12, but elevate the level of reactive oxygen species and pro-inflammatory cytokines.
RESULTS
Here, we studied the formation and organization of various actin microstructures such as-podosome, filopodia and uropod in colocalization with actin nucleator protein Arp2 and scaffold protein TKS5 in Tau-induced microglia by fluorescence microscopy. Further, the relevance of P2Y12 signaling either by activation or blockage was studied in terms of actin structure formations and Tau deposits degradation by N9 microglia. Extracellular Tau oligomers facilitate the microglial migration via Arp2-associated podosome and filopodia formation through the involvement of P2Y12 signaling. Similarly, Tau oligomers induce the TKS5-associated podosome clustering in microglial lamella in a time-dependent manner. Moreover, the P2Y12 was evidenced to localize with F-actin-rich podosome and filopodia during Tau-deposit degradation. The blockage of P2Y12 signaling resulted in decreased microglial migration and Tau-deposit degradation.
CONCLUSIONS
The P2Y12 signaling mediate the formation of migratory actin structures like- podosome and filopodia to exhibit chemotaxis and degrade Tau deposit. These beneficial roles of P2Y12 in microglial chemotaxis, actin network remodeling and Tau clearance can be intervened as a therapeutic target in AD.
PubMed: 37221563
DOI: 10.1186/s13578-023-01028-0 -
European Journal of Cell Biology Apr 2022Cytoskeletal elements are the key players in cellular integrity, structure, signalling and migration. Each cytoskeletal element comprises of properties with respect to... (Review)
Review
Cytoskeletal elements are the key players in cellular integrity, structure, signalling and migration. Each cytoskeletal element comprises of properties with respect to its structure and stability, which serve a specific array of functions. These structures are highly dynamic and regulated by modulation via direct interaction or post-translational modifications. HDAC6 is a cytoplasmic deacetylase known to regulate a wide range of cellular functions either through its deacetylase activity or direct interaction via its C-terminal ZnF UBP domain. HDAC6 has been widely studied for its role in aggresome formation, which acts as a protective mechanism upon protein aggregation. HDAC6 is known to play a critical role in the regulation of cytoskeletal elements-microtubules and actin filaments. This review summarizes the regulatory role of HDAC6 in cytoskeletal remodeling and dynamics of neuronal cells and its significance in neurodegenerative diseases.
Topics: Histone Deacetylase 6; Humans; Microtubules; Neurodegenerative Diseases; Neurons; Protein Aggregates; Protein Processing, Post-Translational
PubMed: 35092942
DOI: 10.1016/j.ejcb.2022.151202 -
American Journal of Medical Genetics.... Aug 2019Frank-Ter Haar syndrome (FTHS), Winchester syndrome (WS), and multicentric osteolysis, nodulosis, and arthropathy (MONA) are ultra-rare multisystem disorders... (Review)
Review
Frank-Ter Haar syndrome (FTHS), Winchester syndrome (WS), and multicentric osteolysis, nodulosis, and arthropathy (MONA) are ultra-rare multisystem disorders characterized by craniofacial malformations, reduced bone density, skeletal and cardiac anomalies, and dermal fibrosis. These autosomal recessive syndromes are caused by homozygous mutation or deletion of respectively SH3PXD2B (SH3 and PX Domains 2B), MMP14 (matrix metalloproteinase 14), or MMP2. Here, we give an overview of the clinical features of 63 previously reported patients with an SH3PXD2B, MMP14, or MMP2 mutation, demonstrating considerable clinical overlap between FTHS, WS, and MONA. Interestingly, the protein products of SH3PXD2B, MMP14, and MMP2 directly cooperate in collagen remodeling. We review animal models for these three disorders that accurately reflect the major clinical features and likewise show significant phenotypical similarity with each other. Furthermore, they demonstrate that defective collagen remodeling is central in the underlying pathology. As such, we propose a nosological revision, placing these SH3PXD2B, MMP14, and MMP2 related syndromes in a novel "defective collagen-remodelling spectrum (DECORS)". In our opinion, this revised nosology better reflects the central role for impaired collagen remodeling, a potential target for pharmaceutical intervention.
Topics: Alleles; Animals; Collagen; Gene Knockdown Techniques; Genetic Association Studies; Genetic Predisposition to Disease; Hajdu-Cheney Syndrome; Humans; Matrix Metalloproteinase 14; Matrix Metalloproteinase 2; Mutation; Phenotype
PubMed: 31218820
DOI: 10.1002/ajmg.a.61264 -
The Journal of Cell Biology Mar 2024The microtubule-associated protein MAP1B has been implicated in axonal growth and brain development. We found that MAP1B is highly expressed in the most aggressive and...
The microtubule-associated protein MAP1B has been implicated in axonal growth and brain development. We found that MAP1B is highly expressed in the most aggressive and deadliest breast cancer subtype, triple-negative breast cancer (TNBC), but not in other subtypes. Expression of MAP1B was found to be highly correlated with poor prognosis. Depletion of MAP1B in TNBC cells impairs cell migration and invasion concomitant with a defect in tumorigenesis. We found that MAP1B interacts with key components for invadopodia formation, cortactin, and Tks5, the latter of which is a PtdIns(3,4)P2-binding and scaffold protein that localizes to invadopodia. We also found that Tks5 associates with microtubules and supports the association between MAP1B and α-tubulin. In accordance with their interaction, depletion of MAP1B leads to Tks5 destabilization, leading to its degradation via the autophagic pathway. Collectively, these findings suggest that MAP1B is a convergence point of the cytoskeleton to promote malignancy in TNBC and thereby a potential diagnostic and therapeutic target for TNBC.
Topics: Humans; Carcinogenesis; Cell Transformation, Neoplastic; Cortactin; Microtubule-Associated Proteins; Triple Negative Breast Neoplasms; MDA-MB-231 Cells; Adaptor Proteins, Vesicular Transport; Microtubules; Cytoskeleton; Female; Animals; Mice; Mice, Inbred BALB C; Podosomes; Tubulin
PubMed: 38353696
DOI: 10.1083/jcb.202303102 -
Cell Reports Aug 2023Invadopodia are extracellular matrix (ECM) degrading structures, which promote cancer cell invasion. The nucleus is increasingly viewed as a mechanosensory organelle...
Invadopodia are extracellular matrix (ECM) degrading structures, which promote cancer cell invasion. The nucleus is increasingly viewed as a mechanosensory organelle that determines migratory strategies. However, how the nucleus crosstalks with invadopodia is little known. Here, we report that the oncogenic septin 9 isoform 1 (SEPT9_i1) is a component of breast cancer invadopodia. SEPT9_i1 depletion diminishes invadopodium formation and the clustering of the invadopodium precursor components TKS5 and cortactin. This phenotype is characterized by deformed nuclei and nuclear envelopes with folds and grooves. We show that SEPT9_i1 localizes to the nuclear envelope and juxtanuclear invadopodia. Moreover, exogenous lamin A rescues nuclear morphology and juxtanuclear TKS5 clusters. Importantly, SEPT9_i1 is required for the amplification of juxtanuclear invadopodia, which is induced by the epidermal growth factor. We posit that nuclei of low deformability favor the formation of juxtanuclear invadopodia in a SEPT9_i1-dependent manner, which functions as a tunable mechanism for overcoming ECM impenetrability.
Topics: Humans; Female; Septins; Podosomes; Protein Isoforms; Breast Neoplasms; Adaptor Proteins, Vesicular Transport; Cell Line, Tumor; Neoplasm Invasiveness
PubMed: 37516960
DOI: 10.1016/j.celrep.2023.112893 -
Nature Communications Nov 2019Basement membrane transmigration during embryonal development, tissue homeostasis and tumor invasion relies on invadosomes, a collective term for invadopodia and...
Basement membrane transmigration during embryonal development, tissue homeostasis and tumor invasion relies on invadosomes, a collective term for invadopodia and podosomes. An adequate structural framework for this process is still missing. Here, we reveal the modular actin nano-architecture that enables podosome protrusion and mechanosensing. The podosome protrusive core contains a central branched actin module encased by a linear actin module, each harboring specific actin interactors and actin isoforms. From the core, two actin modules radiate: ventral filaments bound by vinculin and connected to the plasma membrane and dorsal interpodosomal filaments crosslinked by myosin IIA. On stiff substrates, the actin modules mediate long-range substrate exploration, associated with degradative behavior. On compliant substrates, the vinculin-bound ventral actin filaments shorten, resulting in short-range connectivity and a focally protrusive, non-degradative state. Our findings redefine podosome nanoscale architecture and reveal a paradigm for how actin modularity drives invadosome mechanosensing in cells that breach tissue boundaries.
Topics: Actins; Animals; Cell Adhesion; Cell Membrane; Cell Movement; Cells, Cultured; Dendritic Cells; Humans; Mechanotransduction, Cellular; Mice; Podosomes
PubMed: 31729386
DOI: 10.1038/s41467-019-13123-3 -
Biochimica Et Biophysica Acta.... Jan 2024To explore the novel function of MYO6 on Osteoclast differentiation and its joint destruction capacity in Rheumatoid arthritis mice model.
OBJECTIVES
To explore the novel function of MYO6 on Osteoclast differentiation and its joint destruction capacity in Rheumatoid arthritis mice model.
METHODS
We examined joint erosion in a collagen-induced arthritis (CIA) mouse model using micro-CT, with the mice having a MYO6 knockout background. Inflammatory cytokines were analyzed using an enzyme-linked immunosorbent assay (ELISA). In vitro, we investigated the osteoclastogenesis ability of bone marrow-derived macrophages isolated from MYO6 mice and their littermate controls, examining both morphological and functional differences. Furthermore, we explored podosome formation and endosome maturation using immunofluorescence staining.
RESULTS
We found that MYO6 deficiency attenuated arthritis development and bone destruction in CIA mice as well as impaired osteoclast differentiation by inhibiting NFATc1 induction. Our findings indicate that MYO6 is essential for the organization of podosomes by modulating the FAK/AKT and integrin-β3/Src pathways. MYO6 also mediates endosome transportation by regulating the expression of Rab5 and GM130. This may impact the maintenance and functionality of the ruffled border, as well as the regulation of autophagy in osteoclasts.
CONCLUSION
Our results demonstrated a critical function of MYO6 in osteoclast differentiation and its potential relevance in experimental arthritis.
Topics: Animals; Mice; Arthritis, Experimental; Arthritis, Rheumatoid; Disease Models, Animal; Macrophages; Osteoclasts; Osteogenesis
PubMed: 37816396
DOI: 10.1016/j.bbadis.2023.166902 -
Nano Letters Jun 2023Macrophages are a type of immune cell that helps eliminate pathogens and diseased cells. Recent research has shown that macrophages can sense mechanical cues from...
Macrophages are a type of immune cell that helps eliminate pathogens and diseased cells. Recent research has shown that macrophages can sense mechanical cues from potential targets to perform effective phagocytosis, but the mechanisms behind it remain unclear. In this study, we used DNA-based tension probes to study the role of integrin-mediated forces in FcγR-mediated phagocytosis. The results showed that when the phagocytic receptor FcγR is activated, the force-bearing integrins create a "mechanical barrier" that physically excludes the phosphatase CD45 and facilitates phagocytosis. However, if the integrin-mediated forces are physically restricted at lower levels or if the macrophage is on a soft matrix, CD45 exclusion is significantly reduced. Moreover, CD47-SIRPα "don't eat me" signaling can reduce CD45 segregation by inhibiting the mechanical stability of the integrin barrier. These findings demonstrate how macrophages use molecular forces to identify physical properties and combine them with biochemical signals from phagocytic receptors to guide phagocytosis.
Topics: Receptors, IgG; Integrins; Phagocytosis; Macrophages; Signal Transduction; Carrier Proteins
PubMed: 37289965
DOI: 10.1021/acs.nanolett.3c00957