TY - JOUR
T1 - Ethyl pyruvate inhibits HMGB1 phosphorylation and release by chelating calcium
AU - Shin, Joo Hyun
AU - Kim, Il Doo
AU - Kim, Seung Woo
AU - Lee, Hye Kyung
AU - Jin, Yinchuan
AU - Park, Ju Hun
AU - Kim, Tae Kyung
AU - Suh, Chang Kook
AU - Kwak, Jiyeon
AU - Lee, Keun Hyeung
AU - Han, Pyung Lim
AU - Lee, Ja Kyeong
N1 - Funding Information:
This research was supported by grants from the Mid-Career Researcher Program (grant no. 2012-013195) and the Global Research Network (grant no. 220-2011-1-E00027) of the Korean National Research Foundation (NRF) to J-K Lee.
PY - 2014
Y1 - 2014
N2 - Ethyl pyruvate (EP), a simple aliphatic ester of pyruvic acid, has been shown to have antiinflammatory effects and to confer protective effects in various pathological conditions. Recently, a number of studies have reported EP inhibits high mobility group box 1 (HMGB1) secretion and suggest this might contribute to its antiinflammatory effect. Since EP is used in a calcium-containing balanced salt solution (Ringer solution), we wondered if EP directly chelates Ca(2+) and if it is related to the EP-mediated suppression of HMGB1 release. Calcium imaging assays revealed that EP significantly and dose-dependently suppressed high K(+)-induced transient [Ca(2+)]i surges in primary cortical neurons and, similarly, fluorometric assays showed that EP directly scavenges Ca(2+) as the peak of fluorescence emission intensities of Mag-Fura-2 (a low-affinity Ca(2+) indicator) was shifted in the presence of EP at concentrations of ≥7 mmol/L. Furthermore, EP markedly suppressed the A23187-induced intracellular Ca(2+) surge in BV2 cells and, under this condition, A23187-induced activations of Ca(2+)-mediated kinases (protein kinase Cα and calcium/calmodulin-dependent protein kinase IV), HMGB1 phosphorylation and subsequent secretion of HMGB1 also were suppressed. (A23187 is a calcium ionophore and BV2 cells are a microglia cell line.) Moreover, the above-mentioned EP-mediated effects were obtained independent of cell death or survival, which suggests that they are direct effects of EP. Together, these results indicate that EP directly chelates Ca(2+), and that it is, at least in part, responsible for the suppression of HMGB1 release by EP.
AB - Ethyl pyruvate (EP), a simple aliphatic ester of pyruvic acid, has been shown to have antiinflammatory effects and to confer protective effects in various pathological conditions. Recently, a number of studies have reported EP inhibits high mobility group box 1 (HMGB1) secretion and suggest this might contribute to its antiinflammatory effect. Since EP is used in a calcium-containing balanced salt solution (Ringer solution), we wondered if EP directly chelates Ca(2+) and if it is related to the EP-mediated suppression of HMGB1 release. Calcium imaging assays revealed that EP significantly and dose-dependently suppressed high K(+)-induced transient [Ca(2+)]i surges in primary cortical neurons and, similarly, fluorometric assays showed that EP directly scavenges Ca(2+) as the peak of fluorescence emission intensities of Mag-Fura-2 (a low-affinity Ca(2+) indicator) was shifted in the presence of EP at concentrations of ≥7 mmol/L. Furthermore, EP markedly suppressed the A23187-induced intracellular Ca(2+) surge in BV2 cells and, under this condition, A23187-induced activations of Ca(2+)-mediated kinases (protein kinase Cα and calcium/calmodulin-dependent protein kinase IV), HMGB1 phosphorylation and subsequent secretion of HMGB1 also were suppressed. (A23187 is a calcium ionophore and BV2 cells are a microglia cell line.) Moreover, the above-mentioned EP-mediated effects were obtained independent of cell death or survival, which suggests that they are direct effects of EP. Together, these results indicate that EP directly chelates Ca(2+), and that it is, at least in part, responsible for the suppression of HMGB1 release by EP.
UR - http://www.scopus.com/inward/record.url?scp=84965089222&partnerID=8YFLogxK
U2 - 10.2119/molmed.2014.00039
DO - 10.2119/molmed.2014.00039
M3 - Article
C2 - 25333921
AN - SCOPUS:84965089222
SN - 1528-3658
VL - 20
SP - 649
EP - 657
JO - Molecular medicine (Cambridge, Mass.)
JF - Molecular medicine (Cambridge, Mass.)
ER -