Journal of Neuroimmunology ELSEVIER Journal of Neuroimmunology 65 (1996) 107-l 17 Temporal regulation by adrenergic receptor of macrophage ( M ~$1 -derived tumor necrosis production post-LPS challenge stimulation factor ( TNF) Tracey A. Ignatowski, Samuel Gallant, Robert N. Spengler * zyxwvutsrqponmlkjihgfedcba From the Dept. of Pathology, S. U.N. Y. at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214, USA Received 1 August 1995; revised 20 December 1995; accepted 22 December 1995 Abstract Macrophage (M~J) responsiveness can be regulated by various mediators, including those which emanate from, and mimic, the sympathetic nervous system. Whereas Padrenergic agonists suppress, cY,-adrenergic agonists augment lipopolysaccharide (LPS)-stimu- lated tumor necrosis factor (TNF) production and gene expression. The susceptibility of M+s to regulation of LPS-induced TNF production and mRNA accumulation was examined following /3-adrenergic and cr,-adrenergic receptor activation at specific time points post-LPS challenge. Complete Freund’s adjuvant-elicited murine M+s were incubated with LPS (30 ng/ml) in the presence or absence of adrenergic agonists or antagonists. We assessed the susceptibility of immunologically-activated M 4s to adrenergic receptor regulation: a) during the 1 h delay in the production of TNF after LPS-stimulation, and b) during the rapid increase in TNF production which follows. Disparate responsiveness of M 4s to adrenergic drugs was observed during this time course of TNF production and TNP mRNA accumulation. In particular, while the concomitant addition of an cr,-adrenergic antagonist and LPS resulted in 45% suppression of TNF production, this selective blockade of a,-adrenergic receptors on M& was equally effective throughout the first 45 min post-LPS challenge. After this initial period, the cu,-adrenergic receptor became progressively less responsive as demonstrated by the delayed addition of yohimbine (10e5 M) post-LPS challenge. The addition of the selective a,-adrenergic agonist UK-14304 (10m7 M) to LPS-activated M& augmented TNP mRNA accumulation. However, this augmentation was even greater when the addition of the a,-adrenergic agonist was delayed post-LPS challenge. It was also shown that the /3-adrenergic agonist isoproterenol (10e6 M) produced maximum suppression of TNF production within the first 1.5 h post-LPS challenge. Suppression by isoproterenol (lop6 M) of TNF mRNA accumulation occurred throughout the 2-h period assessed post-LPS stimulation of M&. The decline in isoproterenol-induced regulation was accompanied by an elevation in &-adrenergic receptor mRNA accumulation. Furthermore, suppression of TNF production induced by a maximum concentration of isoproterenol was observed at various LPS concentrations (0.001-1000 ng/ml), although this was not as pronounced a suppression as demonstrated for dibutyryl CAMP. These results demonstrate that the susceptibility of M#G to adrenergic receptor regulation changes throughout the time period necessary for gene activation and ultimate release of TNF. Thus, the production of TNF during LPS-dependent disease states may be regulated by adrenergic mediators throughout different temporal windows, better explaining the role played by the nervous system. Keywords: Tumor necrosis factor; Macrophage; Lipopolysaccharide; Adrenergic; Sympathetic nervous system 1. Introduction addition, the cytokine tumor necrosis factor (TNF), an Neuro-immune communications are becoming increas- ingly recognized as the mechanisms by which the immune system is influenced by the nervous system. Macrophages (M~s), while very capable of being influenced by media- tors emanating from the nervous system, are also effector cells participating in immune/inflammatory processes. In important mediator in a number of disease states, is syn- thesized by stimulated M 4 populations. M +-derived TNF participates in regulating homeostasis, and in helping to maintain many inflammatory/immune processes; there- fore, it is important to understand the endogenous mecha- nisms that control its production. Several mediators have been shown to play a role in the regulation of TNF * Corresponding author. Tel. (716) 829 3102; Fax (716) 829 2086. production by M 4s and, importantly, in M 4 sensitivity to these and other mediators (Spengler et al., 1989a, Spengler 0165-5728/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved PII SOl65-5728(96>00004-5