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Round versus flat: bone cell morphology, elasticity, and mechanosensing.

Publication ,  Journal Article
Bacabac, RG; Mizuno, D; Schmidt, CF; MacKintosh, FC; Van Loon, JJWA; Klein-Nulend, J; Smit, TH
Published in: Journal of biomechanics
January 2008

There is increasing evidence that cell function and mechanical properties are closely related to morphology. However, most in vitro studies investigate flat adherent cells, which might not reflect physiological geometries in vivo. Osteocytes, the mechanosensors in bone, reside within ellipsoid containment, while osteoblasts adhere to flatter bone surfaces. It is unknown whether morphology difference, dictated by the geometry of attachment is important for cell rheology and mechanosensing. We developed a novel methodology for investigating the rheology and mechanosensitivity of bone cells under different morphologies using atomic force microscopy and our two-particle assay for optical tweezers. We found that the elastic constant of MLO-Y4 osteocytes when flat and adherent (>1 kPa) largely differed when round but partially adherent (<1 kPa). The elastic constant of round suspended MLO-Y4 osteocytes, MC3T3-E1 osteoblasts, and primary osteoblasts were similarly <1 kPa. The mechanosensitivity of round suspended MLO-Y4 osteocytes was investigated by monitoring nitric oxide (NO) release, an essential signaling molecule in bone. A preliminary observation of high NO release from round suspended MLO-Y4 osteocytes in response to approximately 5 pN force is reported here, in contrast with previous studies where flat cells routinely release lesser NO while being stimulated with higher force. Our results suggest that a round cellular morphology supports a less stiff cytoskeleton configuration compared with flat cellular morphology. This implies that osteocytes take advantage of their ellipsoid morphology in vivo to sense small strains benefiting bone health. Our assay provides novel opportunities for in vitro studies under a controlled suspended morphology versus commonly studied adherent morphologies.

Duke Scholars

Published In

Journal of biomechanics

DOI

EISSN

1873-2380

ISSN

0021-9290

Publication Date

January 2008

Volume

41

Issue

7

Start / End Page

1590 / 1598

Related Subject Headings

  • Rheology
  • Osteocytes
  • Optical Tweezers
  • Nitric Oxide
  • Microscopy, Atomic Force
  • Mechanotransduction, Cellular
  • Humans
  • Elasticity
  • Cell Shape
  • Cell Line
 

Citation

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Chicago
ICMJE
MLA
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Bacabac, R. G., Mizuno, D., Schmidt, C. F., MacKintosh, F. C., Van Loon, J. J. W. A., Klein-Nulend, J., & Smit, T. H. (2008). Round versus flat: bone cell morphology, elasticity, and mechanosensing. Journal of Biomechanics, 41(7), 1590–1598. https://doi.org/10.1016/j.jbiomech.2008.01.031
Bacabac, Rommel G., Daisuke Mizuno, Christoph F. Schmidt, Fred C. MacKintosh, Jack J. W. A. Van Loon, Jenneke Klein-Nulend, and Theo H. Smit. “Round versus flat: bone cell morphology, elasticity, and mechanosensing.Journal of Biomechanics 41, no. 7 (January 2008): 1590–98. https://doi.org/10.1016/j.jbiomech.2008.01.031.
Bacabac RG, Mizuno D, Schmidt CF, MacKintosh FC, Van Loon JJWA, Klein-Nulend J, et al. Round versus flat: bone cell morphology, elasticity, and mechanosensing. Journal of biomechanics. 2008 Jan;41(7):1590–8.
Bacabac, Rommel G., et al. “Round versus flat: bone cell morphology, elasticity, and mechanosensing.Journal of Biomechanics, vol. 41, no. 7, Jan. 2008, pp. 1590–98. Epmc, doi:10.1016/j.jbiomech.2008.01.031.
Bacabac RG, Mizuno D, Schmidt CF, MacKintosh FC, Van Loon JJWA, Klein-Nulend J, Smit TH. Round versus flat: bone cell morphology, elasticity, and mechanosensing. Journal of biomechanics. 2008 Jan;41(7):1590–1598.
Journal cover image

Published In

Journal of biomechanics

DOI

EISSN

1873-2380

ISSN

0021-9290

Publication Date

January 2008

Volume

41

Issue

7

Start / End Page

1590 / 1598

Related Subject Headings

  • Rheology
  • Osteocytes
  • Optical Tweezers
  • Nitric Oxide
  • Microscopy, Atomic Force
  • Mechanotransduction, Cellular
  • Humans
  • Elasticity
  • Cell Shape
  • Cell Line