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Effects of interfering transmembrane peptides on neuraminidase-1 activity
Elastin is an essential component of numerous human tissues and plays a critical role in elasticity of skin, lungs and arteries. During vascular aging, the elastin network is degraded generating elastin-derived peptides (EDP). The ERC (Elastin Receptor Complex) is a membrane heterotrimeric receptor composed, amongst others, of a membrane-bound neuraminidase, NEU-1. Binding of EDP to the ERC induces the activation of signaling pathways associated with biological effects notably the development of diseases such as atherosclerosis, cancer and diabetes. Previous studies of our laboratory have shown that NEU-1 catalytic activity is linked to its ability to homodimerize. Thus, NEU-1 constitutes a key pharmacological target to fight against deleterious effects of EDP. The aim of this work is to develop by biological/biochemical experiments and molecular dynamic (MD) simulations a transmembrane interfering peptide (pI) able to inhibit specifically NEU-1 dimerization. Peptides are delivered into cells using two strategies, TAT peptides, which are cell-penetrating peptides, or lithium dodecyl sulfate micelles. No cellular toxicity was observed in both approaches. Confocal microscopy underlines a colocalization between pI and NEU-1 at the plasma membrane and coimmunoprecipitation experiments show an interaction between pI and NEU-1. Furthermore, sialidase activity assays point out the ability of pI to inhibit NEU-1 homodimerization (47%; 51%) and its associated sialidase activity (21%;
47%). Preliminary MD simulation studies emphasize that both pI and the transmembrane domain of NEU-1 are stable and helix integrity is conserved in lipid bilayer environments. Moreover, the formation of a spontaneous dimer between NEU-1 and pI was identified. Further MD analyses underline the bio-
logical relevance of our membrane model. These results reveal the ability of pI to bind to NEU-1, inhibit its dimerization and sialidase activity.