In Vitro and in Vivo Nuclear Factor-κB Inhibitory Effects of the Cell-Penetrating Penetratin Peptide

Abstract

Penetratin is a cationic cell-penetrating peptide that has been frequently used for the intracellular delivery of polar bioactive compounds. Recent studies have just revealed the major role of polyanionic membrane proteoglycans and cholesterol-enriched lipid rafts in the uptake of the peptide. Both proteoglycans and lipid-rafts influence inflammatory processes by binding a wide array of proinflammatory mediators; thus, we decided to analyze the effect of penetratin on in vitro and in vivo inflammatory responses. Our in vitro luciferase gene assays demonstrated that penetratin decreased transcriptional activity of nuclear factor-B (NF-B) in tumor necrosis factor (TNF)-stimulated L929 fibroblasts and lipopolysaccharide-activated RAW 264.7 macrophages. Penetratin also inhibited TNF-induced intercellular adhesion molecule-1 expression in human endothelial HMEC-1 cells. Exogenous heparan sulfate abolished the in vitro NF-B inhibitory effects of the peptide. Uptake experiments showed that penetratin was internalized by all of the above-mentioned cell lines in vitro and rapidly entered the cells of the lung and pancreas in vivo. In an in vivo rat model of acute pancreatitis, a disease induced by elevated activities of stress-responsive transcription factors like NF-B, pretreatment with only 2 mg/kg penetratin attenuated the severity of pancreatic inflammation by interfering with IB degradation and subsequent nuclear import of NF-B, inhibiting the expression of proinflammatory genes and improving the monitored laboratory and histological parameters of pancreatitis and associated oxidative stress.

Immunological Response to Peptide Nucleic Acid and its Peptide Conjugate Targeted to Transactivation Response (TAR) Region of HIV-1 RNA Genome

“…Although penetratin peptide has been shown to suppress the infl ammatory response by inhibiting activation and nuclear translocation of nuclear factor-κB (Letoha et al, 2006) in rats, its specifi c immunogenic response is not known. Recently Moschos et al (2007) have used penetratin to deliver small-interfering RNA (siRNA) in lung and shown that siRNA-penetratin conjugate bring forth innate immune response by inducing TNF-α, IFN-α and IL-12 in mice.…”

The role of NF- B activation in the pathogenesis of acute pancreatitis

“…Letoha et al 49 50 described the effects of a novel cell-permeable NF-κB inhibitor. The NLS of the NF-κB p50 subunit was conjugated to the cell-penetrating penetratin peptide.…”

Preclinical safety and efficacy models for pulmonary drug delivery of antimicrobials with focus on in vitro models

“…Changes in gene expression related to inflammation, oxidative stress, and secretion of pro-inflammatory cytokines may allow one to gain insight into the safety of drugs or excipients upon interaction with the respiratory epithelium. Also the activation of NF-κB, a transcription factor mediating inflammatory responses, may serve as an indicator for such events [34].…”