Cationic cell-penetrating peptides interfere with TNF signalling by induction of TNF receptor internalization

Abstract

Cationic cell-penetrating peptides (CPPs) have been used widely as delivery vectors for the import of molecules that otherwise do not cross the plasma membrane of eukaryotic cells. In this work, we demonstrate that the three cationic CPPs, Antennapedia homeodomain-derived peptide (Antp), nona-arginine and Tat-derived peptide, inhibit tumour necrosis factor (TNF)-mediated signal transduction. This inhibition is based on the downregulation of TNF receptors at the cell surface by induction of internalization. In contrast to TNF-dependent receptor internalization, no receptor activation occurs. The receptor downregulation is not restricted to the CPPs. Remarkably, the HIV-1 Tat protein itself also induces the internalization of TNF receptors. The dynamin dependence of the internalization, as well as the fact that epidermal growth factor receptors are also internalized, suggest a general induction of clathrin-dependent endocytosis as the mechanism of action. The significance of these findings for the use of cationic CPPs in the import of bioactive peptides is demonstrated here using a conjugate consisting of Antp and a Smac protein-derived cargo peptide. The cargo alone, when introduced into cells by electroporation, enhanced TNF-induced apoptosis by inhibiting the anti-apoptotic action of IAPs (inhibitor of apoptosis proteins). For the Antp-Smac conjugate at concentrations below 40 μM the inhibitory effect of the Antp peptide compensated for the pro-apoptotic activity of the cargo, and led to the protection of cells against TNF-mediated apoptosis. These data provide important new information for the use of cationic CPPs for the cellular delivery of bioactive molecules.

Endosomal Nox2 Facilitates Redox-Dependent Induction of NF-κB by TNF-α

“…Overexpression of this dominant-negative dynamin (K44A) mutant has been shown to inhibit *75% of transferrinmediated uptake in MCF-7 cells (32). Furthermore, the TNF receptor also appears to depend on dynamin for uptake after ligand binding (14). Expression of the dynamin mutant inhibited TNF-a induction of NF-kB by *40% (Fig.…”

Neuroprotective peptides fused to arginine-rich cell penetrating peptides: Neuroprotective mechanism likely mediated by peptide endocytic properties

“…Furthermore, it is important to note that the rapid and transient (lasting up to 4 h with peptide pre-treatment) nature of the neuroprotection induced by poly-arginine peptides (Meloni et al, 2015) corresponds closely to the timeframes of endocytosis and endosomal receptor re-cycling (Gundelfinger et al, 2003;Maxfield & McGraw, 2004;Yashunsky et al, 2009). Importantly, it is known that TAT, penetratin and R9 can induce the internalisation of EGFR and TNFR in HeLa cells (Fotin-Mleczek et al, 2005). Our hypothesis also links endocytosis as a common neuroprotective mechanism of action for a diverse range of arginine-rich peptides (including TAT-fused peptides), all of which are likely to have endocytic inducing properties.…”

Biodegradable nanoparticles for cytosolic delivery of therapeutics☆

“…These CPPs can ferry molecules or colloidal drug carrier systems that are tagged to them across the cell membrane, into the cytoplasm and to the nucleus [27,28]. The characteristic CPPs is attributed to the presence of a stretch of 9-16 cationic amino acid residues [29]; the most commonly studied CPPs include HIV-1 Transactivating transcriptional activator (TAT) peptide, HSV VP-22 (Herpes Simplex virus type-1 transcription factor) peptide and penetratin [30,31]. Several theories have been proposed to determine the exact mechanism by which these CPPs enter the cells.…”