Potassium conductances and proliferation in conditionally immortalized renal glomerular mesangial cells from the H-2Kb-tsA58 transgenic mouse

Biochim Biophys Acta. 1997 Feb 4;1355(2):191-203. doi: 10.1016/s0167-4889(96)00124-3.

Abstract

The effects of the temperature-sensitive, immortalizing Simian Virus 40 T antigen, tsA58, on whole-cell potassium conductances were assessed in renal glomerular mesangial cells from H-2Kb-tsA58 transgenic mice [1]. MTT cell viability assay data indicated that in permissive (33 degrees C, 50 U ml-1 gamma-interferon, IFN+) and non-permissive (37 degrees C, without gamma-interferon, IFN-) culture conditions the oncogene was active and inactive respectively. In IFN+ cells whole-cell currents were inhibited by 10 mM 4-aminopyridine, 1 mM ATP and glibenclamide (glyburide, IC50 = 0.4 microM) and stimulated by cromakalim (EC50 = 40 microM). Furthermore, increases in pipette free calcium activity stimulated the potassium conductance (EC50 = 0.5 microM). Apamin inhibited this conductance (IC50 = 9 nM). None of these effects were observed in IFN- cells. The potassium conductance in IFN- cells was activated by a hyposmotic shock and this was inhibited by Gd3. These data indicate that (1) conductances consistent with ATP-sensitive and small, calcium-activated potassium channels are found in IFN+ cells, (2) an osmotically-sensitive channel is found in IFN- cells and (3) channel expression is dependent upon the activation of tsA58.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Aminopyridine / chemistry
  • Adenosine Triphosphate / pharmacology
  • Adenylyl Imidodiphosphate / pharmacology
  • Animals
  • Barium / chemistry
  • Calcium / pharmacology
  • Cell Division
  • Cell Line
  • Cesium / chemistry
  • Gadolinium
  • Glomerular Mesangium / chemistry*
  • Glyburide / pharmacology
  • H-2 Antigens / genetics
  • Interferon-gamma
  • Mice
  • Mice, Transgenic
  • Oncogenes
  • Osmolar Concentration
  • Potassium Channels / chemistry*

Substances

  • H-2 Antigens
  • H-2Kb protein, mouse
  • Potassium Channels
  • Cesium
  • Barium
  • Adenylyl Imidodiphosphate
  • Interferon-gamma
  • Adenosine Triphosphate
  • Gadolinium
  • 4-Aminopyridine
  • gadolinium chloride
  • Glyburide
  • Calcium