Article Text

Protein Kinase C-α Mediates Cigarette Smoke Extract- and Complement Factor 5a-Stimulated Interleukin-8 Release in Human Bronchial Epithelial Cells
  1. Ravindra Kashyap,
  2. Anthony A. Floreani,
  3. Arthur J. Heires,
  4. Sam D. Sanderson,
  5. Todd A. Wyatt
  1. From the Pulmonary and Critical Care Medicine Section (R.K., A.A.F., A.J.H., S.D.S., T.A.W.), Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Neb
  2. Research Service (T.A.W.), Department of Veterans Affairs Medical Center, Omaha, Neb.
  1. Address correspondence to: Todd Wyatt, PhD, Department of Internal Medicine, Pulmonary and Critical Care Medicine Section, 985300 Nebraska Medical Center, Omaha, NE 68198-5300. E-mail twyatt{at}
  2. Supported by a US Department of Veterans Affairs Merit Review Grant (to T.A.W.).


Background Cigarette smoke extract (CSE) activates protein kinase C (PKC) and augments complement factor 5a (C5a)-stimulated release of the proinflammatory cytokine IL-8 in human bronchial epithelial cells (HBEC). We hypothesized that PKC activation by alternative PKC activators will also mediate C5a-stimulated IL-8 release in HBEC.

Methods HBEC were treated with phorbol myristate acetate (100 ng/mL), calcium ionophore A23187 (2 nM), or 10 nM cholesterol-3-sulfate in the presence or absence of C5a. Interleukin-8 (IL-8) release was measured by enzyme-linked immunoadsorbent assay.

Results IL-8 release by PKC activators alone was significantly higher than in unstimulated cells and was further augmented in the presence of C5a. Preincubation with the PKC inhibitor calphostin C (1 μM) significantly suppressed IL-8 release in HBEC treated with CSE and C5a. Preincubation with 10 μM TMB-8 (an intracellular calcium sequester) also significantly suppressed IL-8 release in CSE- and C5a-treated HBEC, suggesting that intracellular calcium is required for CSE- and C5a-mediated IL-8 release. When HBEC were preincubated with 30 nM of the PKCβ-specific inhibitor LY363196, CSE- and C5a-mediated IL-8 release was not inhibited. However, with higher concentrations of LY363196 (>600 nM), which exceeds the IC50 for PKCβ greater than 100 fold, CSE- and C5a-mediated IL-8 release was significantly suppressed. Preincubation of HBEC with 100 nM of Gö 6976, a specific PKCα inhibitor, significantly inhibited CSE- and C5a-mediated stimulation of IL-8 release.

Conclusions Collectively, these data suggest that PKC activators in addition to CSE augment C5a-stimulated IL-8 release from HBEC and that CSE and C5a stimulate IL-8 release in HBEC by activating the calcium-dependent PKCα isoform.

Key Words
  • airway epithelium
  • PKC
  • IL-8
  • C5a
  • cigarette smoke

Statistics from

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.