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Mechanisms of the lysophosphatidic acid-induced increase in [Ca(2+)](i) in skeletal muscle cells.

Xu YJ, Tappia PS, Goyal RK, Dhalla NS - J. Cell. Mol. Med. (2008)

Bottom Line: The present study was therefore undertaken to examine the effect of LPA on the [Ca(2+)](i) in C2C12 cells.The LPA effect was also attenuated by ethylene glycolbis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), an extracellular Ca(2+) chelator, Ni(2+) and KB-R7943, inhibitors of the Na(+)-Ca(2+) exchanger; the receptor operated Ca(2+) channel (ROC) blockers, 2-aminoethoxydiphenyl borate and SK&F 96365.However, the L-type Ca(2+) channel blockers, verapamil and diltiazem; the store operated Ca(2+) channel blockers, La(3+) and Gd(3+); a sarcoplasmic reticulum calcium pump inhibitor, thapsigargin; an inositol trisphosphate receptor antagonist, xestospongin and a phospholipase C inhibitor, U73122, did not prevent the increase [Ca(2+)](i) due to LPA.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada.

ABSTRACT
Although lysophosphatidic acid (LPA) is known to increase intracellularfree calcium concentration ([Ca(2+)](i)) in different cell types, the effect of LPA on the skeletal muscle cells is not known. The present study was therefore undertaken to examine the effect of LPA on the [Ca(2+)](i) in C2C12 cells. LPA induced a concentration and time dependent increase in [Ca(2+)](i), which was inhibited by VPC12249, VPC 32183 and dioctanoyl glycerol pyrophosphate, LPA1/3 receptor antagonists. Pertussis toxin, a G(i) protein inhibitor, also inhibited the LPA-induced increase in [Ca(2+)](i). Inhibition of tyrosine kinase activities with tyrphostin A9 and genistein also prevented the increase in [Ca(2+)](i) due to LPA. Likewise, wortmannin and LY 294002, phosphatidylinositol 3-kinase (PI3-K) inhibitors, inhibited [Ca(2+)](i) response to LPA. The LPA effect was also attenuated by ethylene glycolbis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), an extracellular Ca(2+) chelator, Ni(2+) and KB-R7943, inhibitors of the Na(+)-Ca(2+) exchanger; the receptor operated Ca(2+) channel (ROC) blockers, 2-aminoethoxydiphenyl borate and SK&F 96365. However, the L-type Ca(2+) channel blockers, verapamil and diltiazem; the store operated Ca(2+) channel blockers, La(3+) and Gd(3+); a sarcoplasmic reticulum calcium pump inhibitor, thapsigargin; an inositol trisphosphate receptor antagonist, xestospongin and a phospholipase C inhibitor, U73122, did not prevent the increase [Ca(2+)](i) due to LPA. Our data suggest that the LPA-induced increase in [Ca(2+)](i) might occur through G(i)-protein coupled LPA(1/3) receptors that may be linked to tyrosine kinase and PI3-K, and may also involve the Na(+)-Ca(2+) exchanger as well as the ROC. In addition, LPA stimulated C2C12 cell proliferation via PI3-K. Thus, LPA may be an important phospholipid in the regulation of [Ca(2+)](i) and growth of skeletal muscle cells.

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Related in: MedlinePlus

Lysophosphatidic acid-induced changes in nuclear and cytosolic calcium in single C2C12 cells. The C2C12 cells were loaded with 10 μM fluo-3/AM for 30 min. Cells were washed three times with HEPES buffer and scanned in time series with a Nikon TE2000-U confocal microscope. The [Ca2+]i is reflected by the intensity of the green fluorescence of fluo-3.
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fig05: Lysophosphatidic acid-induced changes in nuclear and cytosolic calcium in single C2C12 cells. The C2C12 cells were loaded with 10 μM fluo-3/AM for 30 min. Cells were washed three times with HEPES buffer and scanned in time series with a Nikon TE2000-U confocal microscope. The [Ca2+]i is reflected by the intensity of the green fluorescence of fluo-3.

Mentions: Marius et al.[36] have reported that Ca2+ release from the nucleoplasmic reticulum (NR) plays an important role in the Ca2+ mobilization in C2C12 cells. To investigate whether LPA has an effect on Ca2+ concentration in nucleus, cells were loaded with fluo-3/AM and visualized by confocal microscopy. The fluo-3/AM dye was seen to be highly localized in the nucleus under resting conditions. This could be a reflection of either more [Ca2+]i in the nucleus than in the cytosol or compartmentalization of the dye to the nucleus. It is pointed out that a similar observation has been reported in cultured cortical astrocytes [37]. Exogenous LPA caused a significant increase in the Ca2+ concentration in both the nucleus and cytoplasm (Fig. 5). The peak response was observed at 30 sec after addition of LPA.


Mechanisms of the lysophosphatidic acid-induced increase in [Ca(2+)](i) in skeletal muscle cells.

Xu YJ, Tappia PS, Goyal RK, Dhalla NS - J. Cell. Mol. Med. (2008)

Lysophosphatidic acid-induced changes in nuclear and cytosolic calcium in single C2C12 cells. The C2C12 cells were loaded with 10 μM fluo-3/AM for 30 min. Cells were washed three times with HEPES buffer and scanned in time series with a Nikon TE2000-U confocal microscope. The [Ca2+]i is reflected by the intensity of the green fluorescence of fluo-3.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4401138&req=5

fig05: Lysophosphatidic acid-induced changes in nuclear and cytosolic calcium in single C2C12 cells. The C2C12 cells were loaded with 10 μM fluo-3/AM for 30 min. Cells were washed three times with HEPES buffer and scanned in time series with a Nikon TE2000-U confocal microscope. The [Ca2+]i is reflected by the intensity of the green fluorescence of fluo-3.
Mentions: Marius et al.[36] have reported that Ca2+ release from the nucleoplasmic reticulum (NR) plays an important role in the Ca2+ mobilization in C2C12 cells. To investigate whether LPA has an effect on Ca2+ concentration in nucleus, cells were loaded with fluo-3/AM and visualized by confocal microscopy. The fluo-3/AM dye was seen to be highly localized in the nucleus under resting conditions. This could be a reflection of either more [Ca2+]i in the nucleus than in the cytosol or compartmentalization of the dye to the nucleus. It is pointed out that a similar observation has been reported in cultured cortical astrocytes [37]. Exogenous LPA caused a significant increase in the Ca2+ concentration in both the nucleus and cytoplasm (Fig. 5). The peak response was observed at 30 sec after addition of LPA.

Bottom Line: The present study was therefore undertaken to examine the effect of LPA on the [Ca(2+)](i) in C2C12 cells.The LPA effect was also attenuated by ethylene glycolbis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), an extracellular Ca(2+) chelator, Ni(2+) and KB-R7943, inhibitors of the Na(+)-Ca(2+) exchanger; the receptor operated Ca(2+) channel (ROC) blockers, 2-aminoethoxydiphenyl borate and SK&F 96365.However, the L-type Ca(2+) channel blockers, verapamil and diltiazem; the store operated Ca(2+) channel blockers, La(3+) and Gd(3+); a sarcoplasmic reticulum calcium pump inhibitor, thapsigargin; an inositol trisphosphate receptor antagonist, xestospongin and a phospholipase C inhibitor, U73122, did not prevent the increase [Ca(2+)](i) due to LPA.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada.

ABSTRACT
Although lysophosphatidic acid (LPA) is known to increase intracellularfree calcium concentration ([Ca(2+)](i)) in different cell types, the effect of LPA on the skeletal muscle cells is not known. The present study was therefore undertaken to examine the effect of LPA on the [Ca(2+)](i) in C2C12 cells. LPA induced a concentration and time dependent increase in [Ca(2+)](i), which was inhibited by VPC12249, VPC 32183 and dioctanoyl glycerol pyrophosphate, LPA1/3 receptor antagonists. Pertussis toxin, a G(i) protein inhibitor, also inhibited the LPA-induced increase in [Ca(2+)](i). Inhibition of tyrosine kinase activities with tyrphostin A9 and genistein also prevented the increase in [Ca(2+)](i) due to LPA. Likewise, wortmannin and LY 294002, phosphatidylinositol 3-kinase (PI3-K) inhibitors, inhibited [Ca(2+)](i) response to LPA. The LPA effect was also attenuated by ethylene glycolbis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), an extracellular Ca(2+) chelator, Ni(2+) and KB-R7943, inhibitors of the Na(+)-Ca(2+) exchanger; the receptor operated Ca(2+) channel (ROC) blockers, 2-aminoethoxydiphenyl borate and SK&F 96365. However, the L-type Ca(2+) channel blockers, verapamil and diltiazem; the store operated Ca(2+) channel blockers, La(3+) and Gd(3+); a sarcoplasmic reticulum calcium pump inhibitor, thapsigargin; an inositol trisphosphate receptor antagonist, xestospongin and a phospholipase C inhibitor, U73122, did not prevent the increase [Ca(2+)](i) due to LPA. Our data suggest that the LPA-induced increase in [Ca(2+)](i) might occur through G(i)-protein coupled LPA(1/3) receptors that may be linked to tyrosine kinase and PI3-K, and may also involve the Na(+)-Ca(2+) exchanger as well as the ROC. In addition, LPA stimulated C2C12 cell proliferation via PI3-K. Thus, LPA may be an important phospholipid in the regulation of [Ca(2+)](i) and growth of skeletal muscle cells.

Show MeSH
Related in: MedlinePlus