Human DMBT1-Derived Cell-Penetrating Peptides for Intracellular siRNA Delivery

Abstract

Small interfering RNA (siRNA) is a promising molecule for gene therapy, but its therapeutic administration remains problematic. Among the recently proposed vectors, cell-penetrating peptides show great promise in in vivo trials for siRNA delivery. Human protein DMBT1 (deleted in malignant brain tumor 1) is a pattern recognition molecule that interacts with polyanions and recognizes and aggregates bacteria. Taking advantage of these properties, we investigated whether specific synthetic DMBT1-derived peptides could be used to formulate nanoparticles for siRNA administration. Using an electrophoretic mobility shift assay and UV spectra, we identified two DMBT1 peptides that could encapsulate the siRNA with a self- and co-assembly mechanism. The complexes were stable for at least 2 hr in the presence of either fetal bovine serum (FBS) or RNase A, with peptide-dependent time span protection. ζ-potential, circular dichroism, dynamic light scattering, and transmission electron microscopy revealed negatively charged nanoparticles with an average diameter of 10–800 nm, depending on the reaction conditions, and a spherical or rice-shaped morphology, depending on the peptide and β-helix conformation. We successfully transfected human MCF7 cells with fluorescein isothiocyanate (FITC)-DMBT1-peptide-Cy3-siRNA complexes. Finally, DMBT1 peptides encapsulating an siRNA targeting a fluorescent reporter gene showed efficient gene silencing in MCF7-recombinant cells. These results lay the foundation for a new research line to exploit DMBT1-peptide nanocomplexes for therapeutic siRNA delivery.

Protein Deimination and Extracellular Vesicle Profiles in Antarctic Seabirds

“…Absence of the protein or glycosylation has been described in cancer [183][184][185][186], while roles for post-translational deimination in its multifaceted functions remain unknown. This may be of particular interest as DMBT1 shows a pattern recognition activity for poly-sulfated and poly-phosphorylated ligands, including nucleic acids, and also has the ability to aggregate ligands-properties which have made it a protein of interest for targeted nano-delivery [187]. Therefore, indication of structural changes of this protein via post-translational deimination may be of considerable interest.…”

Cell Penetrating Peptides, Novel Vectors for Gene Therapy

“…Various, creative strategies have been employed to surmount these barriers. Electrostatic charge interaction between cationic CPPs and negatively charged siRNAs have produced self-assembly of CPPs and siRNA into nanoparticles [96][97][98][99]. Escape from endosomal compartments has been achieved by acylation [99], stearylation [100] or histidine modification [101] of the N-terminus of CPPs.…”

Single-cell analysis of human lung epithelia reveals concomitant expression of the SARS-CoV-2 receptor ACE2 with multiple virus receptors and scavengers in alveolar type II cells

“…Also, the study by Stoddard and colleagues demonstrated that transport of HIV-1 can be inhibited by antibodies or peptides that block the interaction of DMBT1 with the HIV-1 envelope protein gp120 58 . Given our findings on DMBT1 expression in lung AT2 cells and its co-expression with ACE2, as well as its reported binding with multiple viruses, we suggest that targeting DMBT1, whether by adding soluble DMBT1-derive peptides 59 among all lung cell subsets AT2 cells displayed highest relative expression of the SARS-CoV-2 receptor ACE2, albeit at a low cell fraction (~2.2% of all AT2 cells). We found that the viral scavenger DMBT1 is highly expressed in AT2 cells and correlates with ACE2 in this compartment.…”