Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1992 Dec;458:633–653. doi: 10.1113/jphysiol.1992.sp019438

Substrate influences rat osteoclast morphology and expression of potassium conductances.

S A Arkett 1, S J Dixon 1, S M Sims 1
PMCID: PMC1175176  PMID: 1338794

Abstract

1. We studied the electrophysiological properties of freshly isolated rat osteoclasts using the whole-cell configuration of the patch-clamp technique. Membrane currents were recorded from cells plated on three substates: dentine, type I collagen and glass. 2. Based on their morphology, we defined two categories of osteoclasts. 'Rounded' osteoclasts were dome-shaped and lacked lamellipodia. 'Spread' osteoclasts were flattened and had lamellipodia. The proportion of 'rounded' osteoclasts was significantly greater when cells were plated on dentine or type I collagen than when cells were plated on glass. 3. 'Spread' osteoclasts expressed an inwardly rectifying K+ conductance regardless of the substrate on which they were plated. 4. 'Rounded' osteoclasts, on all substrates, expressed a transient, outwardly rectifying conductance that was selective for K+ based on: reversal of deactivation tail currents at -74 mV; a 60 mV shift in tail current reversal potential for 10-fold change in [K+]o; and blockade of outward current by extracellular 4-aminopyridine, charybdotoxin, and intracellular Cs+. The outward K+ current had an activation threshold of approximately -50 mV, with half-activation at -29 mV. The current also exhibited voltage-dependent inactivation, with half-inactivation at approximately -40 mV. 5. Outward K+ current in 'rounded' osteoclasts was reduced when extracellular Ca2+ was removed and upon addition of Ni2+, but was unaffected by Cd2+ or nifedipine. 6. 'Rounded' osteoclasts had large whole-cell capacitance for their apparent surface area. Capacitance was positively correlated with K+ conductance. The additional surface membrane we detected through capacitance measurements may be the 'ruffled border' of actively resorbing osteoclasts. 7. We conclude that substrate influences the expression of osteoclast phenotype, as defined by morphology and K+ conductances. 'Rounded' osteoclasts express an outwardly rectifying K+ conductance, with no apparent inwardly rectifying K+ conductance. In contrast, 'spread' osteoclasts exhibit an inwardly rectifying K+ conductance with no outwardly rectifying K+ conductance. The 'spread' phenotype may represent a motile phase, while the 'rounded' phenotype may represent a resorptive phase of osteoclastic activity.

Full text

PDF
633

Images in this article

637Fig. 1
on p.637

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Ali N. N., Boyde A., Jones S. J. Motility and resorption: osteoclastic activity in vitro. Anat Embryol (Berl) 1984;170(1):51–56. doi: 10.1007/BF00319457. [DOI] [PubMed] [Google Scholar]
  2. Baron R., Neff L., Brown W., Louvard D., Courtoy P. J. Selective internalization of the apical plasma membrane and rapid redistribution of lysosomal enzymes and mannose 6-phosphate receptors during osteoclast inactivation by calcitonin. J Cell Sci. 1990 Nov;97(Pt 3):439–447. doi: 10.1242/jcs.97.3.439. [DOI] [PubMed] [Google Scholar]
  3. Baron R., Neff L., Louvard D., Courtoy P. J. Cell-mediated extracellular acidification and bone resorption: evidence for a low pH in resorbing lacunae and localization of a 100-kD lysosomal membrane protein at the osteoclast ruffled border. J Cell Biol. 1985 Dec;101(6):2210–2222. doi: 10.1083/jcb.101.6.2210. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Blair H. C., Teitelbaum S. L., Ghiselli R., Gluck S. Osteoclastic bone resorption by a polarized vacuolar proton pump. Science. 1989 Aug 25;245(4920):855–857. doi: 10.1126/science.2528207. [DOI] [PubMed] [Google Scholar]
  5. Boyde A., Ali N. N., Jones S. J. Resorption of dentine by isolated osteoclasts in vitro. Br Dent J. 1984 Mar 24;156(6):216–220. doi: 10.1038/sj.bdj.4805313. [DOI] [PubMed] [Google Scholar]
  6. Castle N. A., Haylett D. G., Jenkinson D. H. Toxins in the characterization of potassium channels. Trends Neurosci. 1989 Feb;12(2):59–65. doi: 10.1016/0166-2236(89)90137-9. [DOI] [PubMed] [Google Scholar]
  7. Chambers T. J., Magnus C. J. Calcitonin alters behaviour of isolated osteoclasts. J Pathol. 1982 Jan;136(1):27–39. doi: 10.1002/path.1711360104. [DOI] [PubMed] [Google Scholar]
  8. Connor J. A., Stevens C. F. Voltage clamp studies of a transient outward membrane current in gastropod neural somata. J Physiol. 1971 Feb;213(1):21–30. doi: 10.1113/jphysiol.1971.sp009365. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Datta H. K., MacIntyre I., Zaidi M. Intracellular calcium in the control of osteoclast function. I. Voltage-insensitivity and lack of effects of nifedipine, BAYK8644 and diltiazem. Biochem Biophys Res Commun. 1990 Feb 28;167(1):183–188. doi: 10.1016/0006-291x(90)91748-h. [DOI] [PubMed] [Google Scholar]
  10. Davies J., Warwick J., Totty N., Philp R., Helfrich M., Horton M. The osteoclast functional antigen, implicated in the regulation of bone resorption, is biochemically related to the vitronectin receptor. J Cell Biol. 1989 Oct;109(4 Pt 1):1817–1826. doi: 10.1083/jcb.109.4.1817. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Fox A. P., Nowycky M. C., Tsien R. W. Single-channel recordings of three types of calcium channels in chick sensory neurones. J Physiol. 1987 Dec;394:173–200. doi: 10.1113/jphysiol.1987.sp016865. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Gluck S., Cannon C., Al-Awqati Q. Exocytosis regulates urinary acidification in turtle bladder by rapid insertion of H+ pumps into the luminal membrane. Proc Natl Acad Sci U S A. 1982 Jul;79(14):4327–4331. doi: 10.1073/pnas.79.14.4327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
  14. Hermann A., Erxleben C. Charybdotoxin selectively blocks small Ca-activated K channels in Aplysia neurons. J Gen Physiol. 1987 Jul;90(1):27–47. doi: 10.1085/jgp.90.1.27. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Humphries M. J. The molecular basis and specificity of integrin-ligand interactions. J Cell Sci. 1990 Dec;97(Pt 4):585–592. doi: 10.1242/jcs.97.4.585. [DOI] [PubMed] [Google Scholar]
  16. Kanehisa J., Heersche J. N. Osteoclastic bone resorption: in vitro analysis of the rate of resorption and migration of individual osteoclasts. Bone. 1988;9(2):73–79. doi: 10.1016/8756-3282(88)90106-8. [DOI] [PubMed] [Google Scholar]
  17. Kanehisa J., Yamanaka T., Doi S., Turksen K., Heersche J. N., Aubin J. E., Takeuchi H. A band of F-actin containing podosomes is involved in bone resorption by osteoclasts. Bone. 1990;11(4):287–293. doi: 10.1016/8756-3282(90)90082-a. [DOI] [PubMed] [Google Scholar]
  18. Kelly M. E., Dixon S. J., Sims S. M. Inwardly rectifying potassium current in rabbit osteoclasts: a whole-cell and single-channel study. J Membr Biol. 1992 Mar;126(2):171–181. doi: 10.1007/BF00231915. [DOI] [PubMed] [Google Scholar]
  19. Lakkakorpi P. T., Vänänen H. K. Kinetics of the osteoclast cytoskeleton during the resorption cycle in vitro. J Bone Miner Res. 1991 Aug;6(8):817–826. doi: 10.1002/jbmr.5650060806. [DOI] [PubMed] [Google Scholar]
  20. MacKinnon R., Reinhart P. H., White M. M. Charybdotoxin block of Shaker K+ channels suggests that different types of K+ channels share common structural features. Neuron. 1988 Dec;1(10):997–1001. doi: 10.1016/0896-6273(88)90156-0. [DOI] [PubMed] [Google Scholar]
  21. Malgaroli A., Meldolesi J., Zallone A. Z., Teti A. Control of cytosolic free calcium in rat and chicken osteoclasts. The role of extracellular calcium and calcitonin. J Biol Chem. 1989 Aug 25;264(24):14342–14347. [PubMed] [Google Scholar]
  22. Marty A. The physiological role of calcium-dependent channels. Trends Neurosci. 1989 Nov;12(11):420–424. doi: 10.1016/0166-2236(89)90090-8. [DOI] [PubMed] [Google Scholar]
  23. Miller C., Moczydlowski E., Latorre R., Phillips M. Charybdotoxin, a protein inhibitor of single Ca2+-activated K+ channels from mammalian skeletal muscle. Nature. 1985 Jan 24;313(6000):316–318. doi: 10.1038/313316a0. [DOI] [PubMed] [Google Scholar]
  24. Miyauchi A., Hruska K. A., Greenfield E. M., Duncan R., Alvarez J., Barattolo R., Colucci S., Zambonin-Zallone A., Teitelbaum S. L., Teti A. Osteoclast cytosolic calcium, regulated by voltage-gated calcium channels and extracellular calcium, controls podosome assembly and bone resorption. J Cell Biol. 1990 Dec;111(6 Pt 1):2543–2552. doi: 10.1083/jcb.111.6.2543. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Ravesloot J. H., Ypey D. L., Vrijheid-Lammers T., Nijweide P. J. Voltage-activated K+ conductances in freshly isolated embryonic chicken osteoclasts. Proc Natl Acad Sci U S A. 1989 Sep;86(17):6821–6825. doi: 10.1073/pnas.86.17.6821. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Rudy B. Diversity and ubiquity of K channels. Neuroscience. 1988 Jun;25(3):729–749. doi: 10.1016/0306-4522(88)90033-4. [DOI] [PubMed] [Google Scholar]
  27. Sims S. M., Dixon S. J. Inwardly rectifying K+ current in osteoclasts. Am J Physiol. 1989 Jun;256(6 Pt 1):C1277–C1282. doi: 10.1152/ajpcell.1989.256.6.C1277. [DOI] [PubMed] [Google Scholar]
  28. Sims S. M., Kelly M. E., Dixon S. J. K+ and Cl- currents in freshly isolated rat osteoclasts. Pflugers Arch. 1991 Oct;419(3-4):358–370. doi: 10.1007/BF00371118. [DOI] [PubMed] [Google Scholar]
  29. Turksen K., Kanehisa J., Opas M., Heersche J. N., Aubin J. E. Adhesion patterns and cytoskeleton of rabbit osteoclasts on bone slices and glass. J Bone Miner Res. 1988 Aug;3(4):389–400. doi: 10.1002/jbmr.5650030405. [DOI] [PubMed] [Google Scholar]
  30. Vänänen H. K., Karhukorpi E. K., Sundquist K., Wallmark B., Roininen I., Hentunen T., Tuukkanen J., Lakkakorpi P. Evidence for the presence of a proton pump of the vacuolar H(+)-ATPase type in the ruffled borders of osteoclasts. J Cell Biol. 1990 Sep;111(3):1305–1311. doi: 10.1083/jcb.111.3.1305. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Zaidi M., Datta H. K., Patchell A., Moonga B., MacIntyre I. 'Calcium-activated' intracellular calcium elevation: a novel mechanism of osteoclast regulation. Biochem Biophys Res Commun. 1989 Sep 29;163(3):1461–1465. doi: 10.1016/0006-291x(89)91143-1. [DOI] [PubMed] [Google Scholar]
  32. Zaidi M. Modularity of osteoclast behaviour and "mode-specific" inhibition of osteoclast function. Biosci Rep. 1990 Dec;10(6):547–556. doi: 10.1007/BF01116615. [DOI] [PubMed] [Google Scholar]
  33. van Adelsberg J., Al-Awqati Q. Regulation of cell pH by Ca+2-mediated exocytotic insertion of H+-ATPases. J Cell Biol. 1986 May;102(5):1638–1645. doi: 10.1083/jcb.102.5.1638. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES