Mechanical stress‐induced interleukin‐1beta expression through adenosine triphosphate/ P 2 X 7 receptor activation in human periodontal ligament cells

• Published in: Journal of periodontal research Vol. 48; no. 2; pp. 169 - 176
• Main Authors: Kanjanamekanant, K., Luckprom, P., Pavasant, P.
• Format: Journal Article
• Language: English
• Published: 01-04-2013
• ISSN: 0022-3484; 1600-0765
• DOI: 10.1111/j.1600-0765.2012.01517.x

Background and Objective
Mechanical stress is an important factor in maintaining homeostasis of the periodontium.
I
nterleukin‐1beta (
IL
‐1β) and adenosine triphosphate (
ATP
) are considered potent inflammatory mediators. In macrophages,
ATP
‐activated
P
2
X
7 receptor is involved in
IL
‐1β processing and release. Our previous works demonstrated mechanical stress‐induced expression of osteopontin and
RANKL
through the
ATP
/
P
2
Y
1 receptor in human periodontal ligament (
HPDL
) cells. This study was designed to examine the effect of mechanical stress on
IL
‐1β expression in
HPDL
cells, as well as the mechanism and involvement of
ATP
and the
P
2 purinergic receptor.
Material and Methods
Cultured
HPDL
cells were treated with continuous compressive loading.
IL
‐1β expression was analyzed at both
mRNA
and protein levels, using RT‐PCR and
ELISA
, respectively. Cell viability was examined using the
MTT
assay.
ATP
was also used to stimulate
HPDL
cells. Inhibitors, antagonists and the small interfering
RNA
(si
RNA
) technique were used to investigate the role of
ATP
and the specific
P
2 subtypes responsible for
IL
‐1β induction along with the intracellular mechanism.
Results
Mechanical stress could up‐regulate
IL
‐1β expression through the release of
ATP
in
HPDL
cells.
ATP
alone was also capable of increasing
IL
‐1β expression. The induction of
IL
‐1β was markedly inhibited by inhibitors and by si
RNA
targeting the
P
2
X
7 receptor.
ATP
‐stimulated
IL
‐1β expression was also diminished by intracellular calcium inhibitors.
Conclusion
Our work clearly indicates the capability of
HPDL
cells to respond directly to mechanical stimulation. The results signified the important roles of
ATP
/
P
2 purinergic receptors, as well as intracellular calcium signaling, in mechanical stress‐induced inflammation via up‐regulation of the proinflammatory cytokine,
IL
‐1β, in
HPDL
cells.