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Journal ArticleDOI

Nano-topography sensing by osteoclasts.

01 May 2010-Journal of Cell Science (The Company of Biologists Ltd)-Vol. 123, Iss: 10, pp 1503-1510
TL;DR: It was observed that steps or sub-micrometer cracks on the smooth surface stimulate local ring formation, raising the possibility that similar imperfections on bone surfaces may stimulate local osteoclast resorptive activity.
Abstract: Bone resorption by osteoclasts depends on the assembly of a specialized, actin-rich adhesive ‘sealing zone’ that delimits the area designed for degradation. In this study, we show that the level of roughness of the underlying adhesive surface has a profound effect on the formation and stability of the sealing zone and the associated F-actin. As our primary model substrate, we use ‘smooth’ and ‘rough’ calcite crystals with average topography values of 12 nm and 530 nm, respectively. We show that the smooth surfaces induce the formation of small and unstable actin rings with a typical lifespan of ~8 minutes, whereas the sealing zones formed on the rough calcite surfaces are considerably larger, and remain stable for more than 6 hours. It was further observed that steps or sub-micrometer cracks on the smooth surface stimulate local ring formation, raising the possibility that similar imperfections on bone surfaces may stimulate local osteoclast resorptive activity. The mechanisms whereby the physical properties of the substrate influence osteoclast behavior and their involvement in osteoclast function are discussed.

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Citations
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Book ChapterDOI
01 Jan 2015
TL;DR: This chapter presents a complete review of theSi-HAp and highlights the influence of the Si incorporation on the material characteristics and properties by describing its microstructure, sintering behavior, in vitro bioactivity, cellular response, and biomedical applications.
Abstract: Silicon-substituted hydroxyapatites (Si-HAps) have gained a lot of attention due to the improved bioactivity and biological responsiveness with respect to pure hydroxyapatite (HAp). This chapter presents a complete review of the Si-HAp and highlights the influence of the Si incorporation on the material characteristics and properties by describing its microstructure, sintering behavior, in vitro bioactivity, cellular response, and biomedical applications. In particular, this review starts with the description of the Si presence in the connective tissues and its influence on the bone cell metabolism. It continues through the synthesis procedures and the properties of Si-HAps in the form of powders, granules, scaffolds, and coatings. It focuses in detail on the investigation of the Si-HAps' bioactivity and biocompatibility, with an overview of the most important in vitro and in vivo studies. Finally, the last part of the chapter summarizes the documented clinical applications of Si-HAp and emphasizes some recent attempts to improve its bioactivity by designing biomimetic/smart materials based on it.

23 citations

Journal ArticleDOI
TL;DR: The thermal responsiveness of the PNIPAAmSt microgel arrays was examined by spectroscopic ellipsometry and the results unraveled that the thermoresponsive behavior of the arrays was highly consistent with the microgels dispersed in the bulk, showing high dependence on the content of styrene.

22 citations

Book ChapterDOI
TL;DR: The different types of mechanical signals that cells encounter within the body are described and the current knowledge on the role of Mechanical signals in regulating macrophage, monocyte, and dendritic cell function is reviewed.
Abstract: Tissue homeostasis is not only controlled by biochemical signals but also through mechanical forces that act on cells. Yet, while it has long been known that biochemical signals have profound effects on cell biology, the importance of mechanical forces has only been recognized much more recently. The types of mechanical stress that cells experience include stretch, compression, and shear stress, which are mainly induced by the extracellular matrix, cell-cell contacts, and fluid flow. Importantly, macroscale tissue deformation through stretch or compression also affects cellular function.Immune cells such as macrophages and dendritic cells are present in almost all peripheral tissues, and monocytes populate the vasculature throughout the body. These cells are unique in the sense that they are subject to a large variety of different mechanical environments, and it is therefore not surprising that key immune effector functions are altered by mechanical stimuli. In this chapter, we describe the different types of mechanical signals that cells encounter within the body and review the current knowledge on the role of mechanical signals in regulating macrophage, monocyte, and dendritic cell function.

20 citations

Journal ArticleDOI
22 Nov 2018
TL;DR: This review briefly summarizes current knowledge of the osteoclast actin cytoskeleton and describes myosins’ roles in osteoclasts’ differentiation, migration, and actin superstructure patterning.
Abstract: Skeletal quantity and quality are determined by processes of bone modeling and remodeling, which are undertaken by cells that build and resorb bone as they respond to mechanical, hormonal, and other external and internal signals. As the sole bone resorptive cell type, osteoclasts possess a remarkably dynamic actin cytoskeleton that drives their function in this enterprise. Actin rearrangements guide osteoclasts’ capacity for precursor fusion during differentiation, for migration across bone surfaces and sensing of their composition, and for generation of unique actin superstructures required for the resorptive process. In this regard, it is not surprising that myosins, the superfamily of actin-based motor proteins, play key roles in osteoclast physiology. This review briefly summarizes current knowledge of the osteoclast actin cytoskeleton and describes myosins’ roles in osteoclast differentiation, migration, and actin superstructure patterning.

19 citations


Cites background from "Nano-topography sensing by osteocla..."

  • ...In addition, topographically rough surfaces such as native bone promote formation of stable sealing zones, while smooth surfaces tend to promote small, unstable actin rings [11,46,50]....

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Journal ArticleDOI
TL;DR: The analysis of cell proliferation revealed a difference between machined and laser-treated specimens, and plain laser treatment increases surface roughness and wettability, but does not seem to lead to improved biocompatibility.
Abstract: Nanostructured titanium has become a useful material for biomedical applications such as dental implants. Certain surface properties (grain size, roughness, wettability) are highly expected to promote cell adhesion and osseointegration. The aim of this study was to compare the biocompatibilities of several titanium materials using human osteoblast cell line hFOB 1.19. Eight different types of specimens were examined: machined commercially pure grade 2 (cpTi2) and 4 (cpTi4) titanium, nanostructured titanium of the same grades (nTi2, nTi4), and corresponding specimens with laser-treated surfaces (cpTi2L, cpTi4L, nTi2L, nTi4L). Their surface topography was evaluated by means of scanning electron microscopy. Surface roughness was measured using a mechanical contact profilometer. Specimens with laser-treated surfaces had significantly higher surface roughness. Wettability was measured by the drop contact angle method. Nanostructured samples had significantly higher wettability. Cell proliferation after 48 hours from plating was assessed by viability and proliferation assay. The highest proliferation of osteoblasts was found in nTi4 specimens. The analysis of cell proliferation revealed a difference between machined and laser-treated specimens. The mean proliferation was lower on the laser-treated titanium materials. Although plain laser treatment increases surface roughness and wettability, it does not seem to lead to improved biocompatibility.

19 citations


Cites background from "Nano-topography sensing by osteocla..."

  • ...It has previously been demonstrated that nano-size irregularities and nano-patterns have an effect on in vitro cell behavior, such as cell proliferation, cell differentiation, and cell activity [44,45]....

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References
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Journal ArticleDOI
25 Aug 2006-Cell
TL;DR: Naive mesenchymal stem cells are shown here to specify lineage and commit to phenotypes with extreme sensitivity to tissue-level elasticity, consistent with the elasticity-insensitive commitment of differentiated cell types.

12,204 citations


"Nano-topography sensing by osteocla..." refers background in this paper

  • ...…cell proliferation, gene expression and cell viability (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Kunzler et al., 2007; Lo et al., 2000; Roach et al., 2007; Saltel et al., 2004; Vogel and Sheetz, 2006)....

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  • ...…et al., 1999; Roach et al., 2007; Shimizu et al., 1989), local density of the adhesive ligands (Arnold et al., 2004; Arnold et al., 2008; Hirschfeld-Warneken et al., 2008), and physical properties (Bershadsky et al., 2006a; Bershadsky et al., 2006b; Engler et al., 2006; Vogel and Sheetz, 2006)....

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  • ...…a widespread cellular phenomenon, whereby cells collect information on the substrate on which they grow, integrate it, and develop a response (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Vogel and Sheetz, 2006)....

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  • ...…respond to chemical and physical properties of the underlying matrix, such as rigidity, mechanical activity, ligand density and dimensionality (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Vogel and Sheetz, 2006)....

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Journal ArticleDOI
18 Nov 2005-Science
TL;DR: An understanding of how tissue cells—including fibroblasts, myocytes, neurons, and other cell types—sense matrix stiffness is just emerging with quantitative studies of cells adhering to gels with which elasticity can be tuned to approximate that of tissues.
Abstract: Normal tissue cells are generally not viable when suspended in a fluid and are therefore said to be anchorage dependent. Such cells must adhere to a solid, but a solid can be as rigid as glass or softer than a baby's skin. The behavior of some cells on soft materials is characteristic of important phenotypes; for example, cell growth on soft agar gels is used to identify cancer cells. However, an understanding of how tissue cells-including fibroblasts, myocytes, neurons, and other cell types-sense matrix stiffness is just emerging with quantitative studies of cells adhering to gels (or to other cells) with which elasticity can be tuned to approximate that of tissues. Key roles in molecular pathways are played by adhesion complexes and the actinmyosin cytoskeleton, whose contractile forces are transmitted through transcellular structures. The feedback of local matrix stiffness on cell state likely has important implications for development, differentiation, disease, and regeneration.

5,889 citations


"Nano-topography sensing by osteocla..." refers background in this paper

  • ...…a widespread cellular phenomenon, whereby cells collect information on the substrate on which they grow, integrate it, and develop a response (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Vogel and Sheetz, 2006)....

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  • ...…migration, ECM remodeling, cell proliferation, gene expression and cell viability (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Kunzler et al., 2007; Lo et al., 2000; Roach et al., 2007; Saltel et al., 2004; Vogel…...

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  • ...…respond to chemical and physical properties of the underlying matrix, such as rigidity, mechanical activity, ligand density and dimensionality (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Vogel and Sheetz, 2006)....

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Journal ArticleDOI
30 May 1997-Science
TL;DR: Human and bovine capillary endothelial cells were switched from growth to apoptosis by using micropatterned substrates that contained extracellular matrix-coated adhesive islands of decreasing size to progressively restrict cell extension.
Abstract: Human and bovine capillary endothelial cells were switched from growth to apoptosis by using micropatterned substrates that contained extracellular matrix-coated adhesive islands of decreasing size to progressively restrict cell extension. Cell spreading also was varied while maintaining the total cell-matrix contact area constant by changing the spacing between multiple focal adhesion-sized islands. Cell shape was found to govern whether individual cells grow or die, regardless of the type of matrix protein or antibody to integrin used to mediate adhesion. Local geometric control of cell growth and viability may therefore represent a fundamental mechanism for developmental regulation within the tissue microenvironment.

4,641 citations


"Nano-topography sensing by osteocla..." refers background in this paper

  • ...…a widespread cellular phenomenon, whereby cells collect information on the substrate on which they grow, integrate it, and develop a response (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Vogel and Sheetz, 2006)....

    [...]

  • ...…respond to chemical and physical properties of the underlying matrix, such as rigidity, mechanical activity, ligand density and dimensionality (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Vogel and Sheetz, 2006)....

    [...]

  • ...…cellular processes, including adhesion, migration, ECM remodeling, cell proliferation, gene expression and cell viability (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Kunzler et al., 2007; Lo et al., 2000; Roach…...

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Journal ArticleDOI
TL;DR: It is discovered that changes in tissue rigidity and strain could play an important controlling role in a number of normal and pathological processes involving cell locomotion, including morphogenesis, the immune response, and wound healing.

3,189 citations


"Nano-topography sensing by osteocla..." refers background in this paper

  • ...…cell proliferation, gene expression and cell viability (Bershadsky et al., 2006a; Chen et al., 1997; Diener et al., 2005; Discher et al., 2005; Engler et al., 2006; Geiger et al., 2009; Kunzler et al., 2007; Lo et al., 2000; Roach et al., 2007; Saltel et al., 2004; Vogel and Sheetz, 2006)....

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Journal ArticleDOI
23 Nov 2001-Science
TL;DR: These distinctive in vivo 3D-matrix adhesions differ in structure, localization, and function from classically described in vitro adhesion, and as such they may be more biologically relevant to living organisms.
Abstract: Adhesions between fibroblastic cells and extracellular matrix have been studied extensively in vitro, but little is known about their in vivo counterparts. Here, we characterized the composition and function of adhesions in three-dimensional (3D) matrices derived from tissues or cell culture. "3D-matrix adhesions" differ from focal and fibrillar adhesions characterized on 2D substrates in their content of alpha5beta1 and alphavbeta3 integrins, paxillin, other cytoskeletal components, and tyrosine phosphorylation of focal adhesion kinase (FAK). Relative to 2D substrates, 3D-matrix interactions also display enhanced cell biological activities and narrowed integrin usage. These distinctive in vivo 3D-matrix adhesions differ in structure, localization, and function from classically described in vitro adhesions, and as such they may be more biologically relevant to living organisms.

3,000 citations


"Nano-topography sensing by osteocla..." refers background in this paper

  • ...Many cell types react to changes in the threedimensional texture of the substrate at the nanometer- and micrometer scales, by altering their adhesion, motility and orientation (Cukierman et al., 2001; Curtis and Wilkinson, 1997; Geiger, 2001; Vogel and Sheetz, 2006)....

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  • ...The interplay between topography, force and adhesion dynamics might also affect other, mechanosensitive adhesions such as focal adhesions, possibly accounting for changes in their stability, signaling activity and dynamics, when plated on a rough threedimensional matrix (Cukierman et al., 2001)....

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