Separation and Partial Characterization of Neuropeptide-lnducing Factors in Heart Cell Conditioned Medium
Various conditioned media contain multiple factors that regulate the expression of the neurotransmitters acetylcholine, serotonin, and catecholamines and the neuropeptides substance P, somatostatin, vasoactive intestinal polypeptide-related peptides, cholecystokinin, and enkephalins in cultured sympathetic neurons. Using biochemical and immunological methods, we identify at least three distinct factors in heart cell conditioned medium: one induces acetylcholine, substance P, somatostatin, and vasoactive intestinal polypeptide-related peptides while suppressing catecholamine expression, a second factor induces only vasoactive intestinal polypeptide-related peptides, and a third factor induces only somatostatin expression. These observations demonstrate the existence of a group of biochemically and immunologically distinct factors involved in phenotypic specification with unique, but partially overlapping activities. The analogy with the family of differentiation factors in the hematopoietic system is discussed.
© 1990 Cell Press. Received 1 September 1989, Revised 2 November 1989. We wish to thank Keiko Fukada for helpful discussions and detailed advice about protein purification, Bruce Patton for instruction concerning HPLC, Sigrun Korsching and Mahendra Rao for providing affinity-purified anti-heart cell cholinergic factor antiserum, and Nagesh Mahanthappa and Dinah Sah for comments on the manuscript. We are also grateful to Doreen McDowell for the preparation of tissue culture media and collagen, and Josette Carnahan for the preparation of nerve growth factor. This work was supported by a Javits Neuroscience Investigator Award and a McKnight Foundation Neuroscience Research Project Award to P. H. P. H. N. was a postdoctoral fellow of the Muscular Dystrophy Association and the Del Webb Foundation.