NEUROPEPTIDE-Y (NPY) ENHANCES PROLIFERATION OF HUMAN COLONIC LAMINA PROPRIA LYMPHOCYTES

Neuropeptide Y (NPY) is one member of a family of peptides with a wide range of physiological effects on the CNS, cardiovascular, and respir atory systems. NPY is widely distributed throughout the peripheral and central nervous systems. It has also been found within the colon, liv er and gallbladder in close anatomic proximity to the mucosal immune s ystem. In this study, we investigated the effect of NPY on human gut m ucosal immune function. We examined colonic lamina propria lymphocyte (LPL) proliferation by measuring DNA synthesis, ornithine decarboxylas e (ODC) activity, and polyamine biosynthesis. NPY enhanced ODC activit y and polyamine biosynthesis in Con A-stimulated LPL, and enhanced thy midine incorporation into Con A-stimulated LPL but not into monocyte-d epleted LPL. Moreover, exogenous IL1-beta partially restored NPY's sti mulatory effect on monocyte-depleted LPL DNA synthesis. Our results de monstrate that NPY enhances human colonic LPL proliferation and that t his effect is partially IL1-beta dependent. Our data also suggest that NPY's effect may be mediated via polyamine biosynthesis. We postulate that the NPY may have an important impact on human mucosal immune fun ction.