Peptide-Based 2-Aminophenylamide Probes for Targeting Endogenous Class†I Histone Deacetylase Complexes.

Lysine deacetylases or histone deacetylases (HDACs) remove acetylation markers from numerous cellular proteins, thereby regulating their function and activity. Recently established peptide probes containing the HDAC-trapping amino acid α-aminosuberic acid ω-hydroxamate (AsuHd) have been used to investigate the compositions of HDAC complexes in a site-specific manner. Here we report the new HDAC-trapping amino acid 2-amino-8-[(2-aminophenyl)amino]-8-oxooctanoic acid (AsuApa) and the utility of AsuApa-containing probes for HDAC complex profiling on a proteome-wide scale. Unlike AsuHd-containing probes, AsuApa enriched only HDACs 1, 2, and 3 efficiently and was the most potent probe tested for capturing the last of these. These findings indicate that the inherent specificity of reported small-molecule pimelic diphenylamide HDAC inhibitors is preserved in AsuApa and that this HDAC-trapping amino acid represents a potent tool for investigating class I HDAC complexes.

Pericytes support neutrophil transmigration via interleukin-8 across a porcine co-culture model of the blood-brain barrier.

Transmigration of neutrophils across the blood-brain barrier (BBB) to an inflamed brain tissue is an important process during neuronal inflammation. The process of neutrophil activation as well as their way of rolling along the endothelium and their transmigration is quite well understood. Nevertheless, relatively little is known about the fate of neutrophils after they have transmigrated through the endothelium. The role of the other cells of the neurovascular unit in this process is also poorly understood. Here we studied the potential of pericytes to chemo-attract neutrophils under inflammatory conditions. Quantitative real time PCR, western blot analysis, and a chemotaxis assay showed that pericytes are able to chemo-attract neutrophils by interleukin-8 (IL-8) after stimulation with lipopolysaccharides (LPS), tumor necrosis factor-alpha (TNF-α), or interleukin-1beta (IL-1ß). Then, a co-culture model consisting of primary porcine brain capillary endothelial cells (PBCECs) and primary porcine brain capillary pericytes (PBCPs) was used to analyze neutrophil transmigration across the BBB. As a model for inflammation, LPS was used and the effects of the cytokines TNF-α, IL-1ß, and interferon-gamma (IFN-γ) were analyzed. In general, all stimulants apart from IFN-γ were able to increase transendothelial neutrophil migration. This effect was significantly reduced by a specific inhibitor of matrix metalloproteinases (MMPs)-2 and -9. MMP-2/-9 secretion is expected to decrease adhesion to pericytes and thus support the transmigration of neutrophils. Additionally, in an adhesion experiment, we showed that MMP-2/-9 inhibition significantly enhances the adhesion of neutrophils to pericytes.