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Biomolecules Feb 2023The interface between the cellular actin network and diverse forms of integrin-mediated cell adhesions displays a unique capacity to serve as accurate chemical and... (Review)
Review
The interface between the cellular actin network and diverse forms of integrin-mediated cell adhesions displays a unique capacity to serve as accurate chemical and mechanical sensors of the cell's microenvironment. Focal adhesion-like structures of diverse cell types, podosomes in osteoclasts, and invadopodia of invading cancer cells display distinct morphologies and apparent functions. Yet, all three share a similar composition and mode of coupling between a protrusive structure (the lamellipodium, the core actin bundle of the podosome, and the invadopodia protrusion, respectively), and a nearby adhesion site. Cytoskeletal or external forces, applied to the adhesion sites, trigger a cascade of unfolding and activation of key adhesome components (e.g., talin, vinculin, integrin), which in turn, trigger the assembly of adhesion sites and generation of adhesion-mediated signals that affect cell behavior and fate. The structural and molecular mechanisms underlying the dynamic crosstalk between the actin cytoskeleton and the adhesome network are discussed.
Topics: Actins; Integrins; Cytoskeleton; Cell Adhesion; Actin Cytoskeleton
PubMed: 36830665
DOI: 10.3390/biom13020294 -
The Journal of Investigative Dermatology Aug 2023Signaling through the HGF receptor/Met in skin-resident Langerhans cells (LCs) and dermal dendritic cells (DCs) is essential for their emigration toward draining lymph...
Signaling through the HGF receptor/Met in skin-resident Langerhans cells (LCs) and dermal dendritic cells (DCs) is essential for their emigration toward draining lymph nodes upon inflammation-induced activation. In this study, we addressed the role of Met signaling in distinct steps of LC/dermal DC emigration from the skin by employing a conditionally Met-deficient mouse model (Met). We found that Met deficiency severely impaired podosome formation in DCs and concomitantly decreased the proteolytic degradation of gelatin. Accordingly, Met-deficient LCs failed to efficiently cross the extracellular matrix-rich basement membrane between the epidermis and the dermis. We further observed that HGF-dependent Met activation reduced the adhesion of bone marrow-derived LCs to various extracellular matrix factors and enhanced the motility of DCs in three-dimensional collagen matrices, which was not the case for Met-deficient LCs/DCs. We found no impact of Met signaling on the integrin-independent amoeboid migration of DCs in response to the CCR7 ligand CCL19. Collectively, our data show that the Met-signaling pathway regulates the migratory properties of DC in HGF-dependent and HGF-independent manners.
Topics: Mice; Animals; Podosomes; Cell Movement; Skin; Langerhans Cells; Signal Transduction; Dendritic Cells; Lymph Nodes
PubMed: 36813160
DOI: 10.1016/j.jid.2022.12.025 -
Methods in Molecular Biology (Clifton,... 2023Angiogenesis is the formation of new blood vessels from the existing vasculature. It is a fundamental process in developmental biology but also a pathological event that...
Angiogenesis is the formation of new blood vessels from the existing vasculature. It is a fundamental process in developmental biology but also a pathological event that initiates or aggravates many diseases. In this complex multistep process, endothelial cells are activated by angiogenic stimuli; undergo specialization in response to VEGF/Notch signaling; degrade the basement membrane of the parent vessel; sprout, migrate, and proliferate to form capillary tubes that branch; and ultimately anastomose with adjacent vessels. Here we describe an assay that mimics the invasion step in vitro. Human microvascular endothelial cells are confronted by a VEGF-enriched basement membrane material in a three-dimensional environment that promotes endothelial cell sprouting, tube formation, and anastomosis. After a few hours, endothelial cells have become tip cells, and vascular sprouts can be observed by phase contrast, fluorescence, or time-lapse microscopy. Sprouting endothelial cells express tip cell markers, display podosomes and filopodia, and exhibit cell dynamics similar to those of angiogenic endothelial cells in vivo. This model provides a system that can be manipulated genetically to study physiological or pathological angiogenesis and that can be used to screen compounds for pro-/anti-angiogenic properties. In this chapter, we describe the key steps in setting up this assay.
Topics: Humans; Endothelial Cells; Vascular Endothelial Growth Factor A; Neovascularization, Physiologic; Podosomes; Neovascularization, Pathologic
PubMed: 36653717
DOI: 10.1007/978-1-0716-2887-4_20 -
Methods in Molecular Biology (Clifton,... 2023Tumor dissemination involves cancer cell migration through the extracellular matrix (ECM). ECM is mainly composed of collagen fibers that oppose cell invasion. To...
Tumor dissemination involves cancer cell migration through the extracellular matrix (ECM). ECM is mainly composed of collagen fibers that oppose cell invasion. To overcome hindrance in the matrix, cancer cells deploy a protease-dependent program in order to remodel the matrix fibers. Matrix remodeling requires the formation of actin-based matrix/plasma membrane contact sites called invadopodia, responsible for collagen cleavage through the accumulation and activity of the transmembrane type-I matrix metalloproteinase (MT1-MMP). In this article, we describe experimental procedures designed to assay for invadopodia formation and for invadopodia activity using 2D and 3D models based on gelatin (denatured collagen) and fibrillar type-I collagen matrices.
Topics: Humans; Podosomes; Cell Line, Tumor; Collagen; Extracellular Matrix; Cell Movement; Matrix Metalloproteinase 14; Neoplasm Invasiveness
PubMed: 36653711
DOI: 10.1007/978-1-0716-2887-4_14 -
Free Radical Biology & Medicine Feb 2023Osteoclast differentiation and function are critical targets for anti-osteoporosis treatment. Oxidative stress also plays an important regulatory role in the...
Osteoclast differentiation and function are critical targets for anti-osteoporosis treatment. Oxidative stress also plays an important regulatory role in the differentiation of osteoclasts. Corylifol A (CA) is a flavonoid extracted from the Psoralea fruit. It has anti-inflammatory and antioxidant properties despite its unknown effect on osteoporosis. This study found that CA prevented estrogen-deficiency-induced bone loss and suppressed osteoclastogenesis in ovariectomized (OVX) mice by inhibiting intracellular reactive oxygen species (ROS) levels. In vivo, CA effectively prevented trabecular bone loss and reduced osteoclasts' number on the bone surface in OVX mice, as demonstrated in micro-CT, osteometry, and immunohistochemical data. However, CA did not affect cortical bone. In vitro, CA inhibited RANKL-induced podosome belt formation, osteoclastogenesis, and bone resorption functions. CA suppressed RANKL-induced ROS by boosting antioxidant enzymes (Catalase and NQO1) and NFATc1 signaling pathway related protein expression, including integrin αvβ3, NFATc1 and CTSK. Moreover, CA inhibited osteoclast-specific genes, including Ctsk, Acp5, and Mmp9. CA also attenuated the MAPK/ERK pathway, but did not affect the NF-κB signaling pathway. In terms of osteogenesis, CA did not inhibit or promote osteogenic differentiation and mineralization in vitro. These results reveal that CA could be a new replacement therapy for treating estrogen-deficiency osteoporosis via suppressing osteoclastogenesis and intracellular ROS.
Topics: Animals; Mice; Osteogenesis; Reactive Oxygen Species; Antioxidants; Osteoclasts; Bone Resorption; Osteoporosis; NF-kappa B; Estrogens; RANK Ligand; NFATC Transcription Factors; Cell Differentiation; Mice, Inbred C57BL
PubMed: 36649902
DOI: 10.1016/j.freeradbiomed.2023.01.017 -
The Journal of Biological Chemistry Feb 2023Osteoporosis is a chronic skeletal condition characterized by low bone mass and deteriorated microarchitecture of bone tissue and puts tens of millions of people at high...
Osteoporosis is a chronic skeletal condition characterized by low bone mass and deteriorated microarchitecture of bone tissue and puts tens of millions of people at high risk of fractures. New therapeutic agents like i-bodies, a class of next-generation single-domain antibodies, are needed to overcome some limitations of conventional treatments. An i-body is a human immunoglobulin scaffold with two long binding loops that mimic the shape and position of those found in shark antibodies, the variable new antigen receptors of sharks. Its small size (∼12 kDa) and long binding loops provide access to drug targets, which are considered undruggable by traditional monoclonal antibodies. Here, we have successfully identified a human receptor activator of nuclear factor-κB ligand (RANKL) i-body, ADR3, which demonstrates a high binding affinity to human RANKL (hRANKL) with no adverse effect on the survival or proliferation of bone marrow-derived macrophages. Differential scanning fluorimetry suggested that ADR3 is stable and able to tolerate a wide range of physical environments (including both temperature and pH). In addition, in vitro studies showed a dose-dependent inhibitory effect of ADR3 on osteoclast differentiation, podosome belt formation, and bone resorption activity. Further investigation on the mechanism of action of ADR3 revealed that it can inhibit hRANKL-mediated signaling pathways, supporting the in vitro functional observations. These clues collectively indicate that hRANKL antagonist ADR3 attenuates osteoclast differentiation and bone resorption, with the potential to serve as a novel therapeutic to protect against bone loss.
Topics: Humans; Bone Resorption; Cell Differentiation; Macrophages; Osteoclasts; RANK Ligand; Signal Transduction; Single-Domain Antibodies
PubMed: 36634847
DOI: 10.1016/j.jbc.2023.102889 -
Ageing Research Reviews Mar 2023With increasing age, bone tissue undergoes significant alterations in composition, architecture, and metabolic functions, probably causing senile osteoporosis.... (Review)
Review
With increasing age, bone tissue undergoes significant alterations in composition, architecture, and metabolic functions, probably causing senile osteoporosis. Osteoporosis possess the vast majority of bone disease and associates with a reduction in bone mass and increased fracture risk. Bone loss is on account of the disorder in osteoblast-induced bone formation and osteoclast-induced bone resorption. As a unique bone resorptive cell type, mature bone-resorbing osteoclasts exhibit dynamic actin-based cytoskeletal structures called podosomes that participate in cell-matrix adhesions specialized in the degradation of mineralized bone matrix. Podosomes share many of the same molecular constitutions as focal adhesions, but they have a unique structural organization, with a central core abundant in F-actin and encircled by scaffolding proteins, kinases and integrins. Here, we conclude recent advancements in our knowledge of the architecture and the functions of podosomes. We also discuss the regulatory pathways in osteoclast podosomes, providing a reference for future research on the podosomes of osteoclasts and considering podosomes as a therapeutic target for inhibiting bone resorption.
Topics: Humans; Actin Cytoskeleton; Actins; Bone Resorption; Osteoclasts; Podosomes
PubMed: 36621647
DOI: 10.1016/j.arr.2023.101842 -
International Journal of Molecular... Dec 2022Idiopathic pulmonary fibrosis (IPF) is characterized by abnormal fibroblast accumulation in the lung leading to extracellular matrix deposition and remodeling that...
Idiopathic pulmonary fibrosis (IPF) is characterized by abnormal fibroblast accumulation in the lung leading to extracellular matrix deposition and remodeling that compromise lung function. However, the mechanisms of interstitial invasion and remodeling by lung fibroblasts remain poorly understood. The invadosomes, initially described in cancer cells, consist of actin-based adhesive structures that coordinate with numerous other proteins to form a membrane protrusion capable of degrading the extracellular matrix to promote their invasive phenotype. In this regard, we hypothesized that invadosome formation may be increased in lung fibroblasts from patients with IPF. Public RNAseq datasets from control and IPF lung tissues were used to identify differentially expressed genes associated with invadosomes. Lung fibroblasts isolated from bleomycin-exposed mice and IPF patients were seeded with and without the two approved drugs for treating IPF, nintedanib or pirfenidone on fluorescent gelatin-coated coverslips for invadosome assays. Several matrix and invadosome-associated genes were increased in IPF tissues and in IPF fibroblastic foci. Invadosome formation was significantly increased in lung fibroblasts isolated from bleomycin-exposed mice and IPF patients. The degree of lung fibrosis found in IPF tissues correlated strongly with invadosome production by neighboring cells. Nintedanib suppressed IPF and PDGF-activated lung fibroblast invadosome formation, an event associated with inhibition of the PDGFR/PI3K/Akt pathway and TKS5 expression. Fibroblasts derived from IPF lung tissues express a pro-invadosomal phenotype, which correlates with the severity of fibrosis and is responsive to antifibrotic treatment.
Topics: Mice; Animals; Podosomes; Phosphatidylinositol 3-Kinases; Lung; Idiopathic Pulmonary Fibrosis; Fibroblasts; Fibrosis; Bleomycin
PubMed: 36613948
DOI: 10.3390/ijms24010499 -
Methods in Molecular Biology (Clifton,... 2023Cancer cells possess a remarkable capacity to dissociate from a primary tumor, invade the surrounding tissues and vasculature, and eventually form metastases in distant...
Cancer cells possess a remarkable capacity to dissociate from a primary tumor, invade the surrounding tissues and vasculature, and eventually form metastases in distant organs. This complex and multistep process remains one of the major causes of mortality in cancer patients worldwide. Multiple studies have highlighted the role of actin-rich structures called invadopodia ("invasive feet"), which adhere to the matrix, contain and secrete matrix-degrading proteinases, and apply protrusive forces generated by the actin cytoskeleton, which drive the invasive process. Here, we describe a fluorescent microscopy-based protocol for imaging and quantifying both invadopodia formation and matrix degradation.
Topics: Humans; Podosomes; Extracellular Matrix; Actins; Actin Cytoskeleton; Cell Line, Tumor; Neoplasm Invasiveness
PubMed: 36587098
DOI: 10.1007/978-1-0716-2851-5_12 -
The Journal of Cell Biology Feb 2023Invadopodia formation is regulated by Rho GTPases. However, the molecular mechanisms that control Rho GTPase signaling at invadopodia remain poorly understood. Here, we...
Invadopodia formation is regulated by Rho GTPases. However, the molecular mechanisms that control Rho GTPase signaling at invadopodia remain poorly understood. Here, we have identified ARHGAP17, a Cdc42-specific RhoGAP, as a key regulator of invadopodia in breast cancer cells and characterized a novel ARHGAP17-mediated signaling pathway that controls the spatiotemporal activity of Cdc42 during invadopodia turnover. Our results show that during invadopodia assembly, ARHGAP17 localizes to the invadopodia ring and restricts the activity of Cdc42 to the invadopodia core, where it promotes invadopodia growth. Invadopodia disassembly starts when ARHGAP17 translocates from the invadopodia ring to the core, in a process that is mediated by its interaction with the Cdc42 effector CIP4. Once at the core, ARHGAP17 inactivates Cdc42 to promote invadopodia disassembly. Our results in invadopodia provide new insights into the coordinated transition between the activation and inactivation of Rho GTPases.
Topics: cdc42 GTP-Binding Protein; Podosomes; rho GTP-Binding Proteins; Signal Transduction; Cell Line, Tumor; Humans; Breast Neoplasms; GTPase-Activating Proteins
PubMed: 36571786
DOI: 10.1083/jcb.202207020