Ikari A, Atomi K, Kinjo K, Sasaki Y, Sugatani J. Magnesium deprivation inhibits a MEK-ERK cascade and cell proliferation in renal epithelial Madin-Darby canine kidney cells.
Life Sci 2010;
86:766-73. [PMID:
20338184 DOI:
10.1016/j.lfs.2010.03.016]
[Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/06/2010] [Accepted: 03/11/2010] [Indexed: 10/19/2022]
Abstract
AIMS
Loss of magnesium (Mg(2+)) inhibits cell proliferation and augments nephrotoxicant-induced renal injury, but the role of Mg(2+) has not been clarified in detail. We examined the effect of extracellular Mg(2+) deprivation on a MEK-ERK cascade and cell proliferation using a renal epithelial cell line, Madin-Darby canine kidney (MDCK) cells.
MAIN METHODS
MDCK cells were cultured in Mg(2+)-containing or Mg(2+)-free media. A HA-tagged constitutively active (CA)-MEK1 and a dominant negative (DN)-MEK1 were transfected into MDCK cells. The level of protein was examined by Western blotting. The intracellular free Mg(2+) concentration ([Mg(2+)](i)) was measured using a fluorescent dye, mag-fura 2. Cell proliferation was determined by WST-1 assay. Dead cells were identified by staining with annexin V-FITC and propidium iodide.
KEY FINDINGS
In the presence of fetal calf serum (FCS), Mg(2+) deprivation decreased phosphorylated-ERK1/2 (p-ERK1/2) levels and [Mg(2+)](i). Re-addition of Mg(2+) increased p-ERK1/2 levels, which were inhibited by U0126, a specific inhibitor of a MEK-ERK cascade. Glutathione-S-transferase pull-down and coimmunoprecipitation assays showed that CA-MEK1 and DN-MEK1 binds with ERK1/2 in the presence of Mg(2+). In contrast, neither CA-MEK1 nor DN-MEK1 bound to ERK1/2 in the absence of Mg(2+). These results indicate that the MEK-ERK cascade is regulated by [Mg(2+)](i). Cell proliferation was increased by the treatment with FCS or the expression of CA-MEK1 in the presence of Mg(2+), but was inhibited by Mg(2+) deprivation. Mg(2+) deprivation did not increase the number of dead cells.
SIGNIFICANCE
Mg(2+) is involved in the regulation of the MEK-ERK cascade and cell proliferation in MDCK cells.
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