Functional gap junctions between osteocytic and osteoblastic cells

Clare E Yellowley-genetos, Zhongyong Li, Zhiyi Zhou, Christopher R. Jacobs, Henry J. Donahue

Research output: Contribution to journalArticle

188 Citations (Scopus)

Abstract

Morphological evidence shows that osteocytes, bone cells that exist enclosed within bone matrix, are connected to one another and to surface osteoblasts via gap junctions; however, it is unknown whether these gap junctions are functional. Using a newly established murine osteocytic cell line MLO-Y4, we have examined functional gap junctional intercellular communication (GJIC) between osteocytic cells and between osteocytic and osteoblastic cells. In our hands, MLO-Y4 cells express phenotypic characteristics of osteocytic cells including a stellate morphology, low alkaline phosphatase activity, and increased osteocalcin messenger RNA (mRNA) compared with osteoblastic cells. Northern and Western blot analysis revealed that MLO-Y4 cells express abundant connexin 43 (Cx43) mRNA and protein, respectively. Lucifer yellow dye transferred from injected to adjacent cells suggesting that osteocytic cells were functionally coupled via gap junctions. Functional GJIC between osteocytic and osteoblastic (MC3T3-E1) cells was determined by monitoring the passage of calcein dye between the two cell types using a double labeling technique. The ability of bone cells to communicate a mechanical signal was assessed by mechanically deforming the cell membrane of single MLO-Y4 cells, cocultured with MC3T3-E1 cells. Deformation induced calcium signals in MLO-Y4 cells and those elicited in neighboring MC3T3-E1 cells were monitored with the calcium sensitive dye Fura-2. Our results suggest that osteocytic MLO-Y4 cells express functional gap junctions most likely composed of Cx43. Furthermore, osteocytic and osteoblastic cells are functionally coupled to one another via gap junctions as shown by the ability of calcein to pass between cells and the ability of cells to communicate a mechanically induced calcium response.

Original languageEnglish (US)
Pages (from-to)209-217
Number of pages9
JournalJournal of Bone and Mineral Research
Volume15
Issue number2
StatePublished - 2000
Externally publishedYes

Fingerprint

Gap Junctions
Connexin 43
Calcium
Coloring Agents
Bone and Bones
Osteocytes
Messenger RNA
Bone Matrix
Fura-2

Keywords

  • Bone
  • Calcein
  • Cell-cell communication
  • Connexin 43
  • Mechanotransduction

ASJC Scopus subject areas

  • Surgery

Cite this

Functional gap junctions between osteocytic and osteoblastic cells. / Yellowley-genetos, Clare E; Li, Zhongyong; Zhou, Zhiyi; Jacobs, Christopher R.; Donahue, Henry J.

In: Journal of Bone and Mineral Research, Vol. 15, No. 2, 2000, p. 209-217.

Research output: Contribution to journalArticle

Yellowley-genetos, CE, Li, Z, Zhou, Z, Jacobs, CR & Donahue, HJ 2000, 'Functional gap junctions between osteocytic and osteoblastic cells', Journal of Bone and Mineral Research, vol. 15, no. 2, pp. 209-217.
Yellowley-genetos, Clare E ; Li, Zhongyong ; Zhou, Zhiyi ; Jacobs, Christopher R. ; Donahue, Henry J. / Functional gap junctions between osteocytic and osteoblastic cells. In: Journal of Bone and Mineral Research. 2000 ; Vol. 15, No. 2. pp. 209-217.
@article{eef02dae3f7f4ec999a119e0a81ae715,
title = "Functional gap junctions between osteocytic and osteoblastic cells",
abstract = "Morphological evidence shows that osteocytes, bone cells that exist enclosed within bone matrix, are connected to one another and to surface osteoblasts via gap junctions; however, it is unknown whether these gap junctions are functional. Using a newly established murine osteocytic cell line MLO-Y4, we have examined functional gap junctional intercellular communication (GJIC) between osteocytic cells and between osteocytic and osteoblastic cells. In our hands, MLO-Y4 cells express phenotypic characteristics of osteocytic cells including a stellate morphology, low alkaline phosphatase activity, and increased osteocalcin messenger RNA (mRNA) compared with osteoblastic cells. Northern and Western blot analysis revealed that MLO-Y4 cells express abundant connexin 43 (Cx43) mRNA and protein, respectively. Lucifer yellow dye transferred from injected to adjacent cells suggesting that osteocytic cells were functionally coupled via gap junctions. Functional GJIC between osteocytic and osteoblastic (MC3T3-E1) cells was determined by monitoring the passage of calcein dye between the two cell types using a double labeling technique. The ability of bone cells to communicate a mechanical signal was assessed by mechanically deforming the cell membrane of single MLO-Y4 cells, cocultured with MC3T3-E1 cells. Deformation induced calcium signals in MLO-Y4 cells and those elicited in neighboring MC3T3-E1 cells were monitored with the calcium sensitive dye Fura-2. Our results suggest that osteocytic MLO-Y4 cells express functional gap junctions most likely composed of Cx43. Furthermore, osteocytic and osteoblastic cells are functionally coupled to one another via gap junctions as shown by the ability of calcein to pass between cells and the ability of cells to communicate a mechanically induced calcium response.",
keywords = "Bone, Calcein, Cell-cell communication, Connexin 43, Mechanotransduction",
author = "Yellowley-genetos, {Clare E} and Zhongyong Li and Zhiyi Zhou and Jacobs, {Christopher R.} and Donahue, {Henry J.}",
year = "2000",
language = "English (US)",
volume = "15",
pages = "209--217",
journal = "Journal of Bone and Mineral Research",
issn = "0884-0431",
publisher = "Wiley-Blackwell",
number = "2",

}

TY - JOUR

T1 - Functional gap junctions between osteocytic and osteoblastic cells

AU - Yellowley-genetos, Clare E

AU - Li, Zhongyong

AU - Zhou, Zhiyi

AU - Jacobs, Christopher R.

AU - Donahue, Henry J.

PY - 2000

Y1 - 2000

N2 - Morphological evidence shows that osteocytes, bone cells that exist enclosed within bone matrix, are connected to one another and to surface osteoblasts via gap junctions; however, it is unknown whether these gap junctions are functional. Using a newly established murine osteocytic cell line MLO-Y4, we have examined functional gap junctional intercellular communication (GJIC) between osteocytic cells and between osteocytic and osteoblastic cells. In our hands, MLO-Y4 cells express phenotypic characteristics of osteocytic cells including a stellate morphology, low alkaline phosphatase activity, and increased osteocalcin messenger RNA (mRNA) compared with osteoblastic cells. Northern and Western blot analysis revealed that MLO-Y4 cells express abundant connexin 43 (Cx43) mRNA and protein, respectively. Lucifer yellow dye transferred from injected to adjacent cells suggesting that osteocytic cells were functionally coupled via gap junctions. Functional GJIC between osteocytic and osteoblastic (MC3T3-E1) cells was determined by monitoring the passage of calcein dye between the two cell types using a double labeling technique. The ability of bone cells to communicate a mechanical signal was assessed by mechanically deforming the cell membrane of single MLO-Y4 cells, cocultured with MC3T3-E1 cells. Deformation induced calcium signals in MLO-Y4 cells and those elicited in neighboring MC3T3-E1 cells were monitored with the calcium sensitive dye Fura-2. Our results suggest that osteocytic MLO-Y4 cells express functional gap junctions most likely composed of Cx43. Furthermore, osteocytic and osteoblastic cells are functionally coupled to one another via gap junctions as shown by the ability of calcein to pass between cells and the ability of cells to communicate a mechanically induced calcium response.

AB - Morphological evidence shows that osteocytes, bone cells that exist enclosed within bone matrix, are connected to one another and to surface osteoblasts via gap junctions; however, it is unknown whether these gap junctions are functional. Using a newly established murine osteocytic cell line MLO-Y4, we have examined functional gap junctional intercellular communication (GJIC) between osteocytic cells and between osteocytic and osteoblastic cells. In our hands, MLO-Y4 cells express phenotypic characteristics of osteocytic cells including a stellate morphology, low alkaline phosphatase activity, and increased osteocalcin messenger RNA (mRNA) compared with osteoblastic cells. Northern and Western blot analysis revealed that MLO-Y4 cells express abundant connexin 43 (Cx43) mRNA and protein, respectively. Lucifer yellow dye transferred from injected to adjacent cells suggesting that osteocytic cells were functionally coupled via gap junctions. Functional GJIC between osteocytic and osteoblastic (MC3T3-E1) cells was determined by monitoring the passage of calcein dye between the two cell types using a double labeling technique. The ability of bone cells to communicate a mechanical signal was assessed by mechanically deforming the cell membrane of single MLO-Y4 cells, cocultured with MC3T3-E1 cells. Deformation induced calcium signals in MLO-Y4 cells and those elicited in neighboring MC3T3-E1 cells were monitored with the calcium sensitive dye Fura-2. Our results suggest that osteocytic MLO-Y4 cells express functional gap junctions most likely composed of Cx43. Furthermore, osteocytic and osteoblastic cells are functionally coupled to one another via gap junctions as shown by the ability of calcein to pass between cells and the ability of cells to communicate a mechanically induced calcium response.

KW - Bone

KW - Calcein

KW - Cell-cell communication

KW - Connexin 43

KW - Mechanotransduction

UR - http://www.scopus.com/inward/record.url?scp=0033952126&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033952126&partnerID=8YFLogxK

M3 - Article

VL - 15

SP - 209

EP - 217

JO - Journal of Bone and Mineral Research

JF - Journal of Bone and Mineral Research

SN - 0884-0431

IS - 2

ER -