A novel carboline derivative inhibits nitric oxide formation in macrophages independent of effects on tumor necrosis factor α and interleukin-1β expression

Ana Grodzki, Bhaskar Poola, Nagarekha Pasupuleti, Michael H. Nantz, Pamela J Lein, Fredric A Gorin

Research output: Contribution to journalArticle

6 Scopus citations


Neuropathic pain is a maladaptive immune response to peripheral nerve injury that causes a chronic painful condition refractory to most analgesics. Nitric oxide (NO), which is produced by nitric oxide synthases (NOSs), has been implicated as a key factor in the pathogenesis of neuropathic pain. b-Carbolines are a large group of natural and synthetic indole alkaloids, some of which block activation of nuclear factor k-light-chain-enhancer of activated B cells (NF-κB), a predominant transcriptional regulator of NOS expression. Here, we characterize the inhibitory effects of a novel 6-chloro-8-(glycinyl)-amino-β-carboline (8-Gly carb) on NO formation and NF-κB activation in macrophages. 8-Gly carb was significantly more potent than the NOS inhibitor NG-nitro-Larginine methyl ester in inhibiting constitutive and inducible NO formation in primary rat macrophages. 8-Gly carb interfered with NF-κB-mediated gene expression in differentiated THP1-XBlue cells, a human NF-κB reporter macrophage cell line, but only at concentrations severalfold higher than needed to significantly inhibit NO production. 8-Gly carb also had no effect on tumor necrosis factor a (TNF α)-induced phosphorylation of the p38 mitogenactivated protein kinase in differentiated THP1 cells, and did not inhibit lipopolysaccharide- or TNFα-stimulated expression of TNFα and interleukin-1β. These data demonstrate that relative to other carbolines and pharmacologic inhibitors of NOS, 8-Gly carb exhibits a unique pharmacological profile by inhibiting constitutive and inducible NO formation independent of NF-κB activation and cytokine expression. Thus, this novel carboline derivative holds promise as a parent compound, leading to therapeutic agents that prevent the development of neuropathic pain mediated by macrophage-derived NO without interfering with cytokine expression required for neural recovery following peripheral nerve injury.

Original languageEnglish (US)
Pages (from-to)438-447
Number of pages10
JournalJournal of Pharmacology and Experimental Therapeutics
Issue number3
StatePublished - Mar 1 2015


ASJC Scopus subject areas

  • Pharmacology
  • Molecular Medicine

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