IgA immune complex blunts the contraction of cultured mesangial cells through the inhibition of protein kinase C and intracellular calcium

Jong Shiaw Jin, Chen Wen Yao, Shuk Man Ka, Ting Yu Chin, Sheau Heui Chueh, Herng Sheng Lee, Lai Fa Sheu, Yeh Feng Lin, Wei Hwa Lee, Ann Chen

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Abstract

The effects of IgA immune complex (IgA-IC) on the contractile function of cultured mesangial cells were measured by the changes in planar surface area in response to treatment with agonists. Incubation of mesangial cells with IgA-IC for 24 hours significantly decreased the contractile responses to angiotensin II (10-6 M) and phorbol 12-myristate 13-acetate (PMA, 10-6 M). Pretreatment of mesangial cells with the protein kinase C (PKC) inhibitor, chelerythrine (10-6 M), eliminated the difference in contractile responses to angiotensin II or PMA between the control and IgA-IC groups indicating IgA-IC may inhibit the activity of PKC. The contractile responses to ionomycin were not significantly different between IgA-IC treated and control mesangial cells, suggesting that the contractile machinery is not impaired by IgA-IC. Intracellular calcium, [Ca2+]i measured by changes in fura-2 level in response to ATP or bradykinin, was significantly inhibited in IgA-IC treated mesangial cells, compared to control cells. In contrast, treatment with thapsigargin did not result in significant differences in [Ca2+]i between IgA-IC and control mesangial cells, suggesting that a negligible role of endoplasmic reticulum in the effects of IgA-IC. Using PKC specific antibodies, IgA-IC significantly increased the particulate fraction of PKC-ι of mesangial cells to 141±13% of control, without significantly changing the protein content of PKC-α, -δ and -λ in the cytosolic and particulate fractions. In-summary, IgA-IC inhibits the contractile responses of cultured mesangial cells to agonists by inhibiting the activation of PKC and [Ca2+]i.

Original languageEnglish
Pages (from-to)79-87
Number of pages9
JournalChinese Journal of Physiology
Volume47
Issue number2
Publication statusPublished - Jun 30 2004
Externally publishedYes

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Keywords

  • Contractility
  • Intracellular calcium
  • Mesangial cells
  • Protein kinase C

ASJC Scopus subject areas

  • Physiology

Cite this

Jin, J. S., Yao, C. W., Ka, S. M., Chin, T. Y., Chueh, S. H., Lee, H. S., Sheu, L. F., Lin, Y. F., Lee, W. H., & Chen, A. (2004). IgA immune complex blunts the contraction of cultured mesangial cells through the inhibition of protein kinase C and intracellular calcium. Chinese Journal of Physiology, 47(2), 79-87.