Proliferation of guinea pig tracheal epithelial cells in co-culture with rat dorsal root ganglion neural cells. White, Steven R., Allan Garland, Bruce Gitter, Ian Rodger, Linda E. Alger, Jonathan Necheles, April Raila Nawrocki, and Julian Solway. Section of Pulmonary and Critical Care Medicine, Department of Medicine, Division of Biological Sciences, The University of Chicago, Chicago, Illinois, 60637; the Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, New Jersey, 08903; the CNS Research Division, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, Indiana, 46825, and Merck-Frosst Center for Therapeutic Research, Montreal, Qu[acute]ebec, H9R 4P8, Canada.
APStracts 2:0023L, 1995.
Neuropeptides secreted by sensory afferent nerves in airways may modulate growth of air way epithelial cells. To determine whether airway sensory C-fiber nerves secrete neuropeptides that stimulate airway epithelial cell proliferation, we measured S-phase traversal in guinea pig tracheal epithelial (GPTE) cells after co-culture with rat dorsal root ganglion (DRG) cells. GPTE cells were grown in sub -confluent culture on collagen-coated filters for 2 days. DRG cells were harvested from newborn rat pups and grown in primary culture for 7 - 10 days in separate wells. GPTE and DRG cells then were co -cultured for 48 hr, and 10 mM bromodeoxyuridine (BrdU), a thymidine analog, was added in the final 24 hr. Control GPTE cells were grown under similar conditions but without DRG cells. Co-culture with DRG cells stimulated GPTE cell traversal of S-phase. BrdU labeling in co -cultured GPTE cells was 42.8 +/- 5.8% com pared to 18.1 +/- 7.2% in control GPTE cells (P < 0.001, n = 6). Co-culture in the presence of either the NK1 receptor antagonists LY297911 or CP 99,994, the NK2 receptor antagonist SR 48,968, or the CGRP receptor antagonist hCGRP -(8-37) (10-7 M of each) during co-culture attenuated proliferation of GPTE cells. Treatment with all three antagonists together during co -culture decreased BrdU labeling to 2.4 +/- 0.9% of labeled cells vs 8.5 +/- 0.5% of labeled cells during co-culture without antagonists (n = 4, P < 0.02). DRG cells in co-culture secreted substantial concentra tions of CGRP (71.0 +/- 11.3 (mean +/- SE) pmol/ml), substance P (1.26 +/- 0.35 pmol/ml), and neurokinin A (0.45 +/- 0.10 pmol /ml) (n = 19 for each). Proliferation was stimulated in GPTE cells by treatment with NK1, NK2, and CGRP1 receptor agonists in primary culture. We conclude that rat DRG cells secrete neuropeptides that stimulate GPTE cell growth in co-culture, and that this effect is mediated by NK1, NK2 and CGRP1 receptors. These data suggest that airway sensory nerves may modulate epithelial cell proliferation. 

Received 16 September 1994; accepted in final form 31 January
1995.
APS Manuscript Number L276-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 February 1995.