May 2008
Volume 49, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2008
Bradykinin Activation of Extracellular Signal-Regulated Kinases in Human Trabecular Meshwork Cells
Author Affiliations & Notes
  • J. G. Webb
    Medical University of South Carolina, Charleston, South Carolina
    Pharmacology,
  • X. Yang
    Medical University of South Carolina, Charleston, South Carolina
    Pharmacology,
  • C. E. Crosson
    Medical University of South Carolina, Charleston, South Carolina
    Ophthalmology,
  • Footnotes
    Commercial Relationships  J.G. Webb, None; X. Yang, None; C.E. Crosson, None.
  • Footnotes
    Support  NIH grants EY014653, EY09741, EY014793 and RPB.
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 678. doi:https://doi.org/
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      J. G. Webb, X. Yang, C. E. Crosson; Bradykinin Activation of Extracellular Signal-Regulated Kinases in Human Trabecular Meshwork Cells. Invest. Ophthalmol. Vis. Sci. 2008;49(13):678. doi: https://doi.org/.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose: : Bradykinin (BK) acts on B2 kinin receptors to promote matrix metalloproteinase (MMP) secretion from trabecular meshwork (TM) cells and to increase conventional outflow facility. Because acute secretion of specific MMPs can be dependent on the activity of extracellular signal-regulated MAP kinases (ERK 1/2), experiments were performed to determine BK effects on ERK 1/2 activation in human TM cells.

Methods: : BK signaling was examined in primary cultures of human TM cells studied at passages 2 and 3. Activation of ERK 1/2 was determined by immunoblot of cellular lysates using anti-phospho-ERK 1/2 and anti-ERK 1/2 antibodies.

Results: : Incubation of human TM cells with BK produced a concentration-dependent increase in ERK 1/2 phosphorylation compared to unstimulated cells. The response maximum occurred at 100 nM BK and the EC50 was approximately 1.6 nM. ERK 1/2 phosphorylation was increased four to eight-fold relative to basal activity. BK stimulation of ERK 1/2 activity peaked within 2 to 10 min of exposure and then declined to control levels by 60 min. Treatment of TM cells with the selective B2 kinin receptor agonist, Tyr8-BK, also stimulated ERK 1/2 phosphorylation while the B1 selective agonist, Lys-[Des-Arg9]-BK had no significant effect. In addition, activation of ERK 1/2 by BK was blocked by pretreatment of cells with the B2 receptor antagonist, Hoe-140. BK treatment failed to activate either JNK or p38 MAP kinase. Downregulation of protein kinase C (PKC) by persistent exposure of cells to phorbol 12-myristate 13-acetate prevented BK activation of ERK 1/2. Pretreatment of cells with the nonselective PKC inhibitor, GF109203, had an equivalent effect. Finally, incubation of TM cells with U0126, an inhibitor of MAP kinase kinase (MEK), was also observed to block BK-induced ERK 1/2 phosphorylation.

Conclusions: : These results indicate that BK acts on TM cells to rapidly activate the extracellular signal-regulated MAP kinases, ERK 1/2. This effect is dependent on signaling through the PKC pathway and MEK activation. ERK 1/2 stimulation by BK, like BK actions to increase MMP secretion and enhance outflow facility, is mediated by B2 kinin receptors. The composite of the data supports the idea that BK activates ERK 1/2 in TM cells to promote secretion of constitutively-expressed MMPs and increase aqueous outflow.

Keywords: signal transduction: pharmacology/physiology • receptors: pharmacology/physiology • trabecular meshwork 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×