Regulation of Lipoprotein Homeostasis by Self-Assembling Peptides

Abstract

High levels of serum low-density lipoprotein (LDL) cholesterol contribute to atherosclerosis, a key risk factor of cardiovascular diseases. PCSK9 is a circulatory enzyme that downregulates expression of hepatic LDL receptors, concomitantly increasing serum LDL-C. This work investigates a small, self-assembling peptide, EPep2-8, as a peptide inhibitor of PCSK9. EPep2-8 is a multidomain peptide comprising a self-assembling domain, E2, conjugated to a bioactive domain, Pep2-8, previously shown to inhibit PCSK9. The E2 domain facilitates self-assembly of EPep2-8 into long, nanofibrous polymers with an underlying supramolecular β-sheet secondary structure. Intermolecular interactions between nanofibers drive EPep2-8 to form a thixotropic and cytocompatible hydrogel in aqueous and charge-neutral solutions. These properties enable EPep2-8 to be delivered as an in situ depot for regulation of lipoprotein homeostasis. In surface plasmon resonance studies, EPep2-8 bound specifically to PCSK9 with an apparent, noncovalent, and irreversible dissociation, significantly improving the binding affinity of Pep2-8 alone (K D = 667 ± 48 nM). Increased binding affinity of EPep2-8 is primarily due to the superstoichiometric interaction of the peptide with PCSK9. Promisingly, EPep2-8 retains bioactivity in vitro, engendering dose-dependent uptake of LDL-C in hepatocytes. This mechanism of self-assembly on a target site may be a simple method to improve the affinity of peptide inhibitors.

Self-Assembling Peptides with Insulin-Like Growth Factor Mimicry

“…We generated an IGF-1c mimic attached to a canonical selfassembling peptide domain (sequence: KSLSLSLSLSLSLK) that we have previously applied to other clinical applications. 12,13,15 To optimize the efficacy and biocompatibility of the peptide, we designed peptides with single glycine spacers between the self-assembly domain and IGF-1c mimic (SLG 1 IGF) or with 3 glycine (SLG 3 IGF) or 5 glycine (SLG 5 IGF) spacers (all sequences in Table 1). This series of peptides was synthesized by conventional solid-phase peptide synthesis with C-terminal amidation and N-terminal acetylation, except for commercially available recombinant IGF-1 (Table 1 31 ).…”

“…To display GF mimics within the in situ region, we have utilized a platform of self-assembling peptides (SAP) that comprise amphiphilic domains that promote hydrophobic-phase β-sheet self-assembly into amphiphilic nanofibers. − These highly hydrophilic nanofibers entangle to form hydrogels at ∼ <1 wt %, which rapidly infiltrate with cells and biodegrade over of 3–4 week-long periods in various tissues. , SAPs offer a tunable method of incorporating GF signaling moieties, which can be rationally designed, appended, and synthesized on the termini of the SAP.…”

Label-Free Analysis of Binding and Inhibition of SARS-Cov-19 Spike Proteins to ACE2 Receptor with ACE2-Derived Peptides by Surface Plasmon Resonance

“…SPR is a well-established technique that has been utilized to investigate various biophysical interactions, especially those targeting proteins. − However, using SPR for direct analysis of interactions between small molecules, such as small peptides, and proteins has commonly been a difficulty, largely due to the low signal change caused from small molecule interactions . We, therefore, utilized a competition assay to evaluate the binding of the peptide to the SARS-CoV-2-spike protein using SPR spectroscopy, with Figure providing a schematic of this competition assay.…”

iPSC-derived cranial neural crest-like cells can replicate dental pulp tissue with the aid of angiogenic hydrogel

“…Including the VEGF-motif in the hydrogel monomer sequence is a promising strategy [ [26] , [27] , [28] ]. Further work from our group has shown the facile modifiability of this platform to promote DPSC proliferation, neurogenesis, inflammation modulation, and others [ [76] , [77] , [78] , [79] ]. Recently, stromal cell-derived factor 1 alpha (SDF-1α) was shown to enhance angiogenesis remarkably when overexpressed together with VEGF in DPSCs [ 80 ].…”