Abstract
Objective: To examine the intracellular calcium response to basic calcium phosphate (BCP) crystals in fibroblasts. Design: In this study, intracellular calcium [Ca2+](i) levels in fibroblasts were determined using the photoactive dye, fura-2. Interruption of these responses was accomplished by either removal of Ca2+ from the extracellular medium or addition of ammonium chloride that inhibits intracellular dissolution of BCP crystals by alkalinizing phagolysosomes. The effects of such interruptions on BCP induction expression of proto-oncogenes were demonstrated by the Northern blot analysis. Results: Addition of media containing BCP crystals yielded an immediate 10-fold rise of [Ca2+](i) over the baseline level in human fibroblasts. This peak was derived mostly from extracellular calcium and was not seen when BCP crystals in calcium-free media were added to fibroblasts. The [Ca2+](i) concentration returned to the baseline level within 8 min. A second rise of [Ca2+](i) started at 60 min and continued to increase up to at least 3 h. This peak was derived from intracellular dissolution of phagocytosed crystals and almost completely inhibited by 10 mM ammonium chloride. Conclusion: The initial transient [Ca2+](i) increase probably serves as a second messenger leading to activation of early cellular responses such as c-fos expression which is important in BCP crystal-induced mitogenesis. The second, slower and more sustained rise of [Ca2+](i) probably initiates other cellular processes needed for fibroblast mitogenesis.
| Original language | English |
|---|---|
| Pages (from-to) | 324-329 |
| Number of pages | 6 |
| Journal | Osteoarthritis and Cartilage |
| Volume | 6 |
| Issue number | 5 |
| DOIs | |
| State | Published - Sep 1 1998 |
Fingerprint
Keywords
- Basic calcium phosphate crystals
- Calcium
- Fibroblasts
- Fura-2
ASJC Scopus subject areas
- Orthopedics and Sports Medicine
Cite this
Intracellular calcium responses to basic calcium phosphate crystals in fibroblasts. / Halverson, Paul B.; Greene, Andrew; Cheung, Herman S.
In: Osteoarthritis and Cartilage, Vol. 6, No. 5, 01.09.1998, p. 324-329.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Intracellular calcium responses to basic calcium phosphate crystals in fibroblasts
AU - Halverson, Paul B.
AU - Greene, Andrew
AU - Cheung, Herman S
PY - 1998/9/1
Y1 - 1998/9/1
N2 - Objective: To examine the intracellular calcium response to basic calcium phosphate (BCP) crystals in fibroblasts. Design: In this study, intracellular calcium [Ca2+](i) levels in fibroblasts were determined using the photoactive dye, fura-2. Interruption of these responses was accomplished by either removal of Ca2+ from the extracellular medium or addition of ammonium chloride that inhibits intracellular dissolution of BCP crystals by alkalinizing phagolysosomes. The effects of such interruptions on BCP induction expression of proto-oncogenes were demonstrated by the Northern blot analysis. Results: Addition of media containing BCP crystals yielded an immediate 10-fold rise of [Ca2+](i) over the baseline level in human fibroblasts. This peak was derived mostly from extracellular calcium and was not seen when BCP crystals in calcium-free media were added to fibroblasts. The [Ca2+](i) concentration returned to the baseline level within 8 min. A second rise of [Ca2+](i) started at 60 min and continued to increase up to at least 3 h. This peak was derived from intracellular dissolution of phagocytosed crystals and almost completely inhibited by 10 mM ammonium chloride. Conclusion: The initial transient [Ca2+](i) increase probably serves as a second messenger leading to activation of early cellular responses such as c-fos expression which is important in BCP crystal-induced mitogenesis. The second, slower and more sustained rise of [Ca2+](i) probably initiates other cellular processes needed for fibroblast mitogenesis.
AB - Objective: To examine the intracellular calcium response to basic calcium phosphate (BCP) crystals in fibroblasts. Design: In this study, intracellular calcium [Ca2+](i) levels in fibroblasts were determined using the photoactive dye, fura-2. Interruption of these responses was accomplished by either removal of Ca2+ from the extracellular medium or addition of ammonium chloride that inhibits intracellular dissolution of BCP crystals by alkalinizing phagolysosomes. The effects of such interruptions on BCP induction expression of proto-oncogenes were demonstrated by the Northern blot analysis. Results: Addition of media containing BCP crystals yielded an immediate 10-fold rise of [Ca2+](i) over the baseline level in human fibroblasts. This peak was derived mostly from extracellular calcium and was not seen when BCP crystals in calcium-free media were added to fibroblasts. The [Ca2+](i) concentration returned to the baseline level within 8 min. A second rise of [Ca2+](i) started at 60 min and continued to increase up to at least 3 h. This peak was derived from intracellular dissolution of phagocytosed crystals and almost completely inhibited by 10 mM ammonium chloride. Conclusion: The initial transient [Ca2+](i) increase probably serves as a second messenger leading to activation of early cellular responses such as c-fos expression which is important in BCP crystal-induced mitogenesis. The second, slower and more sustained rise of [Ca2+](i) probably initiates other cellular processes needed for fibroblast mitogenesis.
KW - Basic calcium phosphate crystals
KW - Calcium
KW - Fibroblasts
KW - Fura-2
UR - http://www.scopus.com/inward/record.url?scp=0032170878&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032170878&partnerID=8YFLogxK
U2 - 10.1053/joca.1998.0131
DO - 10.1053/joca.1998.0131
M3 - Article
C2 - 10197167
AN - SCOPUS:0032170878
VL - 6
SP - 324
EP - 329
JO - Osteoarthritis and Cartilage
JF - Osteoarthritis and Cartilage
SN - 1063-4584
IS - 5
ER -