Identification and characterization of CW108F, a novel β-carboline compound that promotes cardiomyogenesis of stem cells

1,5-Disubstituted benzimidazoles that direct cardiomyocyte differentiation from mouse embryonic stem cells

Cardiomyopathy is the leading cause of death worldwide. Despite progress in medical treatments, heart transplantation is one of the only current options for those with infarcted heart muscle. Stem cell differentiation technology may afford cell-based therapeutics that may lead to the generation of new, healthy heart muscle cells from undifferentiated stem cells. Our approach is to use small molecules to stimulate stem cell differentiation. Herein, we describe a novel class of 1,5-disubstituted benzimidazoles that induce differentiation of stem cells into cardiac cells. We report on the evaluation in vitro for cardiomyocyte differentiation and describe structure-activity relationship results that led to molecules with drug-like properties. The results of this study show the promise of small molecules to direct stem cell lineage commitment, to probe signaling pathways and to develop compounds for the stimulation of stem cells to repair damaged heart tissue.

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

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. β-Carbolines are a large group of natural and synthetic indole alkaloids, some of which block activation of nuclear factor κ-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-L-arginine 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 α (TNFα)-induced phosphorylation of the p38 mitogen-activated 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.