TY - JOUR
T1 - Activation of glucose transport during simulated ischemia in H9c2 cardiac myoblasts is mediated by protein kinase C isoforms
AU - Agnetti, Giulio
AU - Maraldi, Tullia
AU - Fiorentini, Diana
AU - Giordano, Emanuele
AU - Prata, Cecilia
AU - Hakim, Gabriele
AU - Muscari, Claudio
AU - Guarnieri, Carlo
AU - Caldarera, Claudio Marcello
N1 - Funding Information:
This research was supported by M.I.U.R., Rome, by University of Bologna (Progetto Pluriennale 1998–2003) and by Compagnia di San Paolo, Turin, Italy.
PY - 2005/12/5
Y1 - 2005/12/5
N2 - Glucose transport into cells may be regulated by a variety of conditions, including ischemia. We investigated whether some enzymes frequently involved in the metabolic adaptation to ischemia are also required for glucose transport activation. Ischemia was simulated by incubating during 3 h H9c2 cardiomyoblasts in a serum- and glucose-free medium in hypoxia. Under these conditions 2-deoxy-d-[2,6-3H]-glucose uptake was increased (57% above control levels, p < 0.0001) consistently with GLUT1 and GLUT4 translocation to sarcolemma. Tyrosine kinases inhibition via tyrphostin had no effect on glucose transport up-regulation induced by simulated ischemia. On the other hand, chelerythrine, a broad range inhibitor of protein kinase C isoforms, and rottlerin, an inhibitor of protein kinase C delta, completely prevented the stimulation of the transport rate. A lower activation of hexose uptake (19%, p < 0.001) followed also treatment with Gö6976, an inhibitor of conventional protein kinases C. Finally, PD98059-mediated inhibition of the phosphorylation of ERK 1/2, a downstream mitogen-activated protein kinase (MAPK), only partially reduced the activation of glucose transport induced by simulated ischemia (31%, p < 0.01), while SB203580, an inhibitor of p38 MAPK, did not exert any effect. These results indicate that stimulation of protein kinase C delta is strongly related to the up-regulation of glucose transport induced by simulated ischemia in cultured cardiomyoblasts and that conventional protein kinases C and ERK 1/2 are partially involved in the signalling pathways mediating this process.
AB - Glucose transport into cells may be regulated by a variety of conditions, including ischemia. We investigated whether some enzymes frequently involved in the metabolic adaptation to ischemia are also required for glucose transport activation. Ischemia was simulated by incubating during 3 h H9c2 cardiomyoblasts in a serum- and glucose-free medium in hypoxia. Under these conditions 2-deoxy-d-[2,6-3H]-glucose uptake was increased (57% above control levels, p < 0.0001) consistently with GLUT1 and GLUT4 translocation to sarcolemma. Tyrosine kinases inhibition via tyrphostin had no effect on glucose transport up-regulation induced by simulated ischemia. On the other hand, chelerythrine, a broad range inhibitor of protein kinase C isoforms, and rottlerin, an inhibitor of protein kinase C delta, completely prevented the stimulation of the transport rate. A lower activation of hexose uptake (19%, p < 0.001) followed also treatment with Gö6976, an inhibitor of conventional protein kinases C. Finally, PD98059-mediated inhibition of the phosphorylation of ERK 1/2, a downstream mitogen-activated protein kinase (MAPK), only partially reduced the activation of glucose transport induced by simulated ischemia (31%, p < 0.01), while SB203580, an inhibitor of p38 MAPK, did not exert any effect. These results indicate that stimulation of protein kinase C delta is strongly related to the up-regulation of glucose transport induced by simulated ischemia in cultured cardiomyoblasts and that conventional protein kinases C and ERK 1/2 are partially involved in the signalling pathways mediating this process.
KW - Glucose transport
KW - H9c2 cardiomyoblasts
KW - Mitogen-activated protein kinases
KW - Protein kinase C
KW - Simulated ischemia
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U2 - 10.1016/j.lfs.2005.04.039
DO - 10.1016/j.lfs.2005.04.039
M3 - Article
C2 - 16111715
AN - SCOPUS:27644529656
SN - 0024-3205
VL - 78
SP - 264
EP - 270
JO - Life Sciences
JF - Life Sciences
IS - 3
ER -