bims-cepepe 2025-07-27 papers

bims-cepepe

Biomed News

on Cell-penetrating peptides

Issue of 2025–07–27
fifteen papers selected by
Henry Lamb, Queensland University of Technology

Ribosomal Incorporation of Fluorosulfonyloxy-l-Phenylalanine into Macrocyclic Peptides for De Novo Target-Specific Covalent Binders.
Trifluoroacetic Acid Promotes Ultrafast Peptide Cyclization Mediated with Dimethylolurea.
Design of linear and cyclic peptide binders from protein sequence information.
Investigating the Interactions of a Cyclic Peptide Hormone Somatostatin and Its Derivatives on Amyloid-Beta Aggregation.
Phosphoproteomic analysis of signal transduction dynamics induced by a modified cell-penetrating peptide-protein complex.
De novo design and structure of a peptide-centric TCR mimic binding module.
Therapeutic Potential of Stylissatin A and Related Cyclic Peptides From Marine Sponges.
Evaluation of synthetic peptides for direct protein delivery into Saccharomyces cerevisiae.
Peptide drug delivery: Permeation behaviour and intracellular fate of hydrophobic ion pairs in self-emulsifying drug delivery systems.
Non-steroidal anti-inflammatory drugs conjugated to a synthetic peptide exhibit in vitro cytotoxic activity against cervical cancer and melanoma cells.
Advances in Peptidomimetics for Next-Generation Therapeutics: Strategies, Modifications, and Applications.
Peptide-based therapeutic and delivery strategies for inflammatory bowel disease: challenges and future directions.
Development of simplified poly(β-aminoester)-zwitterion nanovehicles for controlled cancer cell transfection and enhanced gene delivery across a cell-based model of the blood-brain barrier.
Development of Broad-Spectrum Antimicrobial Peptides through the Conjugation of FtsZ-Binding and Cell-Penetrating Peptides.
Neutral peptides allow aggregation of cationic peptides in antimicrobial secretory fluids.

J Am Chem Soc. 2025 Jul 19.

Ribosomal Incorporation of Fluorosulfonyloxy-l-Phenylalanine into Macrocyclic Peptides for De Novo Target-Specific Covalent Binders.

Yawen Yang, Pei Liu, Xi-Yang Cui, Junjie Wu, Wenfeng Cai, Jie Cheng, Chuanjie Lu, Xiaowei Fan, Youming Zhang, Zhibo Liu, Yizhen Yin.

Macrocyclic peptides are emerging as a promising molecular framework in covalent drug development due to their high specificity, affinity, and low toxicity, addressing challenges such as off-target effects and nonspecific binding associated with traditional covalent binders. Although mRNA display technology has advanced the discovery of covalent peptide binders, it has primarily focused on cysteine residues, thereby limiting the diversity of targetable proteins. In this study, we ribosomally incorporated 4-fluorosulfonyloxy-l-phenylalanine (FSY) into macrocyclic peptides, enabling the construction of a diverse covalent macrocyclic peptide library for de novo screening against human α-thrombin and fibroblast activation protein. This led to the identification of novel peptides with covalent binding capabilities and a distinct dissociation profile, which in turn enabled potent inhibitory activities at concentrations within the low nanomolar range. Notably, FSY-bearing macrocyclic peptides conjugated with a radionuclide chelator demonstrated significantly improved tumor-selective uptake and prolonged retention, outperforming their noncovalent counterparts while underscoring their remarkable potential in targeted radionuclide therapy. This study provided a robust and efficient platform for the de novo discovery of FSY-bearing macrocyclic peptides, broadening the scope of covalent drug development for diverse biomedical applications.

DOI: https://doi.org/10.1021/jacs.5c10625
Org Lett. 2025 Jul 25.

Trifluoroacetic Acid Promotes Ultrafast Peptide Cyclization Mediated with Dimethylolurea.

Shi Wang, Huanhuan Yang, Jinglin Song, Yang Zhao, Cong Liu, Jiaqi Shao, Siqi Zhou, Ganga B Vamisetti, Jingjing Zhang, Feng Xue, Hao Sun.

Cyclic peptides have gained widespread attention as potential medium-sized modulators of biomolecular interactions with large binding surfaces. Effective and user-friendly cyclization methods are increasingly becoming important for researchers across disciplines seeking to access diverse cyclic peptide structures. Here, a highly selective, rapid, and operationally simple method is reported for directly cyclizing unprotected peptides in which dimethylolurea effectively reacts with a pair of cysteine residues within an unprotected peptide sequence, forming a novel cyclic peptide. The reaction occurs in a trifluoroacetic acid-acetonitrile-water system, offering rapid conversion and easy operation. Furthermore, we demonstrate the applicability of dimethylolurea-mediated cyclization to generate cyclic peptides with improved uptake into living cells and enhanced affinity for their target proteins. Overall, this method provides a valuable addition to the peptide engineering toolbox, facilitating the development of functional cyclic peptides for chemical biology and drug discovery.

DOI: https://doi.org/10.1021/acs.orglett.5c02534
Commun Chem. 2025 Jul 22. 8(1): 211

Design of linear and cyclic peptide binders from protein sequence information.

Qiuzhen Li, Efstathios Nikolaos Vlachos, Patrick Bryant.

Structure prediction technology has transformed protein design, yet key challenges remain, particularly in designing novel functions. Many proteins function through interactions with other proteins, making the rational design of these interactions a central problem. While most efforts focus on large, stable proteins, shorter peptides offer advantages such as lower manufacturing costs, reduced steric hindrance, and improved cell permeability when cyclised. However, their flexibility and limited structural data make them difficult to design. Here, we introduce EvoBind2, a method for designing novel linear and cyclic peptide binders of varying lengths using only the sequence of a target protein. Unlike existing approaches, EvoBind2 does not require prior knowledge of binding sites or predefined binder lengths, making it a fully blind design process. For one target protein, we demonstrate that linear and cyclic peptide binders of different lengths can be designed in a single shot, and adversarial designs can be avoided through orthogonal in silico evaluation.

DOI: https://doi.org/10.1038/s42004-025-01601-3
ACS Chem Neurosci. 2025 Jul 21.

Investigating the Interactions of a Cyclic Peptide Hormone Somatostatin and Its Derivatives on Amyloid-Beta Aggregation.

Amy Trinh Pham, Yusheng Zhao, Amy Oo, Ahmed A Hefny, Aravindhan Ganesan, Praveen P N Rao.

  We investigated the effects of cyclic peptides somatostatin, its isomer d-Trp8-somatostatin, and marketed somatostatin derivatives octreotide and lanreotide on Aβ42 aggregation and cytotoxicity in mouse hippocampal HT22 cells. The aggregation kinetic studies show that all the cyclic peptides were able to reduce Aβ42 fibrillogenesis at 1, 5, 10, and 25 μM. The native cyclic peptide somatostatin exhibited superior inhibition compared to other cyclic peptides (91% inhibition at 25 μM) and exhibited greater inhibition compared to the reference agent orange G (86% inhibition at 25 μM), whereas the corresponding isomer d-Trp8-somatostatin exhibited 74% inhibition at 25 μM. The marketed drugs octreotide and lanreotide exhibited a similar inhibition profile (∼54% inhibition at 25 μM). Electron microscopy and immunoblotting experiments also demonstrate their antiaggregation properties. Furthermore, the cyclic peptides were not toxic to mouse hippocampal neuronal HT22 cells and exhibited cell viability ranging from 89 to 98.7% at 10 μM. Strikingly, the cyclic peptides somatostatin, d-Trp8-somatostatin, octreotide, and lanreotide were able to rescue mouse hippocampal neuronal HT22 cells from Aβ42-mediated cytotoxicity (cell viability: 71.7-83.8% at 10 μM). The marketed cyclic peptide drugs octreotide and lanreotide exhibited superior activity (cell viability: 83.8% and 81%, respectively) in preventing Aβ42-induced cytotoxicity compared to somatostatin and d-Trp8-somatostatin. Computational studies were able to identify the potential interaction sites of cyclic peptides in the Aβ42 hexamer assembly. Our studies demonstrate the ability of these cyclic peptides to interact with Aβ42 and reduce Aβ42-induced toxicity, highlighting the potential of marketed drugs octreotide and lanreotide in drug repurposing for Alzheimer's disease.

Keywords:  aggregation kinetics; beta-amyloid; cell viability; d-Trp8-somatostatin-14; immunoblotting; lanreotide; molecular docking; molecular dynamics; neprilysin; octreotide; somatostatin-14; transmission electron microscopy

DOI:  https://doi.org/10.1021/acschemneuro.5c00044
Biochem Biophys Res Commun. 2025 Jul 16. pii: S0006-291X(25)01071-X. [Epub ahead of print]778 152356

Phosphoproteomic analysis of signal transduction dynamics induced by a modified cell-penetrating peptide-protein complex.

Akiko Okuda, Hayato Takihara, Reika Kuroiwa, Shujiro Okuda.

  Cell-penetrating peptides (CPPs) deliver cargo proteins into cells; however, most CPPs rely on nonspecific electrostatic interactions, limiting their cell-type specificity. The CPP Pas2r12 delivers cargo, such as enhanced green fluorescent protein (EGFP) and immunoglobulin G, into the cytosol, primarily through caveolae-dependent endocytosis. To elucidate the intracellular signaling underlying Pas2r12-mediated delivery, time-resolved phosphoproteomic analyses were performed following treatment with Pas2r12 or the Pas2r12-EGFP complex. Early phosphorylation of mitogen-activated protein kinase 1 (MAPK1) and ephrin B1 (EFNB1) was observed following stimulation with either Pas2r12 or the Pas2r12-EGFP complex, whereas F11R phosphorylation occurred only in response to Pas2r12. Notably, MAPK1 phosphorylation consistently increased at all timepoints after stimulation with either treatment. In addition, lysophosphatidic acid receptor 1 (LPAR1) phosphorylation was induced by both treatments at 30 min. EFNB1, F11R, and LPAR1 are cell surface ligands or receptors that are potential targets of Pas2r12 or the Pas2r12-EGFP complex. These results suggest that sustained MAPK1 phosphorylation may play a central role in cellular response to Pas2r12-based delivery. Future studies should aim at establishing Pas2r12 as an efficient and versatile protein delivery tool, with particular focus on exploiting specific cell-surface molecules to enhance targeting specificity.

Keywords:  Caveolae-dependent endocytosis; Cell-penetrating peptide; Enhanced green fluorescent protein; Mitogen-activated protein kinase 1; Phosphoproteomic analysis

DOI:  https://doi.org/10.1016/j.bbrc.2025.152356
Science. 2025 Jul 24. 389(6758): 375-379

De novo design and structure of a peptide-centric TCR mimic binding module.

Karsten D Householder, Xinyu Xiang, Kevin M Jude, Arthur Deng, Matthias Obenaus, Yang Zhao, Steven C Wilson, Xiaojing Chen, Nan Wang, K Christopher Garcia.

T cell receptor (TCR) mimics offer a promising platform for tumor-specific targeting of peptide-major histocompatibility complex (pMHC) in cancer immunotherapy. In this study, we designed a de novo α-helical TCR mimic (TCRm) specific for the NY-ESO-1 peptide presented by human leukocyte antigen (HLA)-A*02, achieving high on-target specificity with nanomolar affinity (dissociation constant Kd = 9.5 nM). The structure of the TCRm-pMHC complex at 2.05-Å resolution revealed a rigid TCR-like docking mode with an unusual degree of focus on the up-facing NY-ESO-1 side chains, suggesting the potential for reduced off-target reactivity. Indeed, a structure-informed in silico screen of 14,363 HLA-A*02 peptides correctly predicted two off-target peptides, yet our TCRm maintained peptide selectivity and cytotoxicity as a T cell engager. These results represent a path for precision targeting of tumor antigens with peptide-focused α-helical TCR mimics.

DOI: https://doi.org/10.1126/science.adv3813
J Pept Sci. 2025 Sep;31(9): e70045

Therapeutic Potential of Stylissatin A and Related Cyclic Peptides From Marine Sponges.

Aaqib Ullah, Farzana Shaheen, Uzma Salar, Andreas G Tzakos, Ioannis P Gerothanassis.

  Marine sponges are sessile invertebrates found in moderate, arctic, and tropical regions, serving as a valuable reservoir of bioactive compounds, particularly Pro-rich peptides. Among these, cyclic peptides have attracted significant interest due to their diverse therapeutic properties. One notable example is Stylissatin A (SA), a Pro-rich cyclic peptide reported from the marine sponge Stylissa massa. SA and its analogues have shown promising biological activities, including anti-inflammatory, anticancer, and anti-obesity effects. Despite the vast potential of marine-derived peptides, only a small number have progressed to the pharmaceutical market. Cyclic peptides like SA offer unique opportunities for molecular modifications and total synthesis, enabling the enhancement of potency, improvement of physicochemical properties, and optimization of synthetic yields. This review highlights the synthetic strategies developed for the total synthesis of SA, explores its structural features and related analogues, and discusses their therapeutic potential, underscoring the promise of SA-based scaffolds as novel peptide-based drug candidates.

Keywords:   Stylissa massa ; anticancer; anti‐inflammatory; anti‐obesity; marine sponges; stylissatin A (SA)

DOI:  https://doi.org/10.1002/psc.70045
Biosci Biotechnol Biochem. 2025 Jul 21. pii: zbaf111. [Epub ahead of print]

Evaluation of synthetic peptides for direct protein delivery into Saccharomyces cerevisiae.

Shota Isogai, Ryoya Tanahashi, Hiroshi Takagi, Akira Nishimura.

  Efficient intracellular delivery of functional proteins into the yeast Saccharomyces cerevisiae remains a major technical challenge due to its rigid cell wall. Here, we report that synthetic peptide tags, particularly penetratin, enable nearly complete delivery of GFP, albeit with substantial cytotoxicity. This method provides a promising non-genetic platform for the intracellular delivery and functional analysis of proteins in yeast systems.

Keywords:   Saccharomyces cerevisiae ; Cell-penetrating peptide; Protein delivery

DOI:  https://doi.org/10.1093/bbb/zbaf111
Eur J Pharm Sci. 2025 Jul 18. pii: S0928-0987(25)00206-4. [Epub ahead of print]212 107207

Peptide drug delivery: Permeation behaviour and intracellular fate of hydrophobic ion pairs in self-emulsifying drug delivery systems.

Martyna Truszkowska, Melanie Lena Ebert, Khush Bakhat Afzal, Váradi Györgyi, Andreas Bernkop-Schnürch.

  This study aimed to investigate the permeation behaviour and intracellular fate of hydrophobic ion pairs (HIP). HIP were formed by combining a daptomycin-derived model peptide (DD) with ethyl lauroyl arginate (ELA) and lipophilic fluorescent dye 4-(4-dihexadecylaminostyryl)-N-methylpyridinium iodide (DiA). A representative HIP (DD: ELA: DiA, molar ratio 1:4:0.5) was incorporated into self-emulsifying drug delivery systems (SEDDS) and characterized for size, zeta potential, stability, hemolytic activity, cytotoxicity, and cellular uptake. Permeability was assessed using the Parallel Artificial Membrane Permeability Assay (PAMPA) model and Caco-2 monolayers. SEDDS exhibited droplet sizes below 200 nm, a polydispersity index (PDI) < 0.4, positive surface charges, and high stability. Hemolysis studies indicated potential for endosomal escape, while dose-dependent toxicity became apparent after 4 and 24 h of incubation. Flow cytometry revealed enhanced cellular uptake: HIP and SEDDS increased internalization of DD by 12- and 32-fold, compared to free peptide. Permeation studies demonstrated marked improvements in DD transport. In the PAMPA assay, HIP and SEDDS increased passive diffusion by 2.8- and 6.5-fold. Similarly, in the Caco-2 model, HIP and SEDDS enhanced permeation by 17- and 57-fold, compared to free DD. DiA permeation remained minimal, suggesting that HIP disassociates intracellularly, allowing selective release of the peptide. These findings confirm that HIP enhances membrane permeation of DD and dissociates after uptake. The combination of HIP and SEDDS presents a robust strategy for improving the oral bioavailability of peptide therapeutics.

Keywords:  Cellular uptake; Ethyl lauroyl arginate; Fluorescent model drugs; Hydrophobic ion pair; PAMPA; Permeation

DOI:  https://doi.org/10.1016/j.ejps.2025.107207
RSC Med Chem. 2025 Jul 11.

Non-steroidal anti-inflammatory drugs conjugated to a synthetic peptide exhibit in vitro cytotoxic activity against cervical cancer and melanoma cells.

Daniel Alejandro Castellar-Almonacid, Andrea Carolina Barragán-Cárdenas, Karla Geraldine Rodríguez-Mejia, Laura Angélica Maldonado-Sanabria, Natalia Ardila-Chantré, Jose David Mendoza-Mendoza, Claudia Marcela Parra-Giraldo, Jhon Erick Rivera-Monroy, Zuly Jenny Rivera-Monroy, Javier Eduardo García-Castañeda, Ricardo Fierro-Medina.

Previous studies have shown that the palindromic peptide RWQWRWQWR derived from bovine lactoferricin (LfcinB) has exhibited selective in vitro cytotoxic effects against multiple cancer cells such as cervical, breast, and prostate cancer. We designed and synthesized peptides based on this palindromic sequence conjugated with non-steroidal anti-inflammatory drugs (NSAIDs) such as naproxen and ibuprofen to obtain novel hybrid peptides that could trigger inflammatory processes within cancer cells. Incorporating the non-natural amino acid ornithine as a spacer was done to improve the aqueous solubility of the NSAID-peptide conjugates. The antibacterial activity of the conjugated peptides was evaluated, and these peptides showed significant activity against E. coli strain ATCC 25922, with MIC values of 12 μM. Cytotoxicity was assessed in human cervical cancer cells (HeLa) and human melanoma cells (A375), showing that the NSAID-conjugated peptides retained and even exhibited better anticancer activity compared to the palindromic peptide from which they were derived. The NSAID-LfcinB conjugates showed good selectivity towards cancer cells in the concentration ranges evaluated, being non-hemolytic. The cytotoxic effect of the IBU-Orn3-1 and NAP-Orn3-1 peptides was rapid and selective, inducing severe morphological changes, including rounding, shrinkage, and vacuole formation, which are associated with apoptosis. Flow cytometry assays revealed that the ibuprofen-conjugated palindromic sequence induced apoptosis independently of peptide concentration and treatment duration. These results suggest that the palindromic peptide RWQWRWQWR could be used for new applications in cancer research, such as delivering small molecules with anti-inflammatory activity in tumoral environments. The conjugation of NSAIDs to anticancer peptide sequences is a novel, viable, and rapid strategy that facilitates the synthesis of hybrid peptides with enhanced anticancer activity, thereby expanding the pool of promising molecules for preclinical and clinical studies in cancer therapy development.

DOI: https://doi.org/10.1039/d5md00476d
Chem Rev. 2025 Jul 23.

Advances in Peptidomimetics for Next-Generation Therapeutics: Strategies, Modifications, and Applications.

Lucia Lombardi, Valentina Del Genio, Fernando Albericio, Daryl R Williams.

Over the past two decades, peptide drug discovery has experienced a remarkable renaissance, with organic chemistry and biotechnology emerging as pivotal tools for developing peptidomimetics that exhibit improved stability, specificity, and bioavailability compared to conventional peptides. This review systematically examines methodologies for modifying peptide backbones to achieve targeted properties, highlighting recent advances facilitated by modern biotechnological innovations for novel molecular transformations. Additionally, the review emphasizes the practical applications of peptides and peptidomimetics, showcasing their successful integration into medicine and pharmacology. This manuscript evaluates achievements and challenges in the field and identifies critical areas for further research. Its overarching aim is to synthesize current knowledge and propose strategic directions for advancing peptide-based therapeutics.

DOI: https://doi.org/10.1021/acs.chemrev.4c00989
RSC Adv. 2025 Jul 15. 15(31): 25560-25578

Peptide-based therapeutic and delivery strategies for inflammatory bowel disease: challenges and future directions.

Chengmei Ge, Zhen Wang, Yu Wang, Meihao Wei.

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), remains a challenging chronic disorder with complex pathophysiology and limited therapeutic options. Peptide-based therapeutics have emerged as promising alternatives, offering high specificity, favorable safety profiles, and unique biological activities compared to traditional treatments. However, challenges including enzymatic degradation, poor oral bioavailability, and instability hinder their clinical translation. This review provides a comprehensive overview of the sources, structures, and mechanisms of therapeutic peptides for IBD management. We further discuss recent advances in delivery strategies, including PEGylation, nanoparticle (NP) systems (chitosan (CS), hyaluronic acid (HA), PLGA, lipid-based carriers, polydopamine (PDA), mesoporous materials), hydrogels, engineered probiotics, and montmorillonite-based composites. Particular emphasis is placed on the role of biomaterials in enhancing peptide stability, targeting specificity, and mucosal adhesion. Key challenges-such as optimizing peptide design, ensuring biosafety, refining delivery systems, and improving preclinical models-are critically analyzed. Prospects suggest that combining smart delivery technologies with data-driven peptide engineering will significantly advance peptide-based therapies for precision IBD management.

DOI: https://doi.org/10.1039/d5ra03731j
Drug Deliv Transl Res. 2025 Jul 25.

Development of simplified poly(β-aminoester)-zwitterion nanovehicles for controlled cancer cell transfection and enhanced gene delivery across a cell-based model of the blood-brain barrier.

Maria C Lucana, Shambhavi Pandey, Salvador Borrós, Benjamí Oller-Salvia.

  Although nucleotide-based therapeutics hold promise for a variety of diseases, their clinical application is limited because of low stability and poor bioavailability. Among non-viral gene delivery vectors, poly(β-aminoester)s (pBAEs) stand out because of their low cytotoxicity, high transfection capacity, and adequate biodegradation profile. Oligopeptide end-Modified pBAEs (OM-pBAEs) enable enhanced polynucleotide encapsulation, cellular internalization, and transfection. Despite the outstanding properties of OM-pBAEs as non-viral gene delivery vectors, traditional OM-pBAE formulations have low cell selectivity and require formulation with two or more polymers. In this study, we first develop a simplified OM-pBAE formulation with a single polymer (pBAE-CRHR) and then add a zwitterionic moiety as part of the end-capping process (pBAE-CRHR-Zw) to decrease unspecific transfection. Subsequently, we recover transfection capacity for target cancer cells in two ways: (i) by addition of a photo-cleavable moiety between the pBAE and the zwitterion, and (ii) by functionalization of pBAEs with BrainBike-4, a bicyclic peptidomimetic targeting the transferrin receptor 1. Finally, we show that derivatization of pBAE-CRHR-Zw with BrainBike-4 enhances transmigration of the gene delivery system across a tight monolayer of human endothelial cells mimicking the BBB.

Keywords:  Brain shuttle peptides; OM-pBAE nanoparticles; Targeted gene delivery; Zwitterionic peptides

DOI:  https://doi.org/10.1007/s13346-025-01902-z
ACS Infect Dis. 2025 Jul 24.

Development of Broad-Spectrum Antimicrobial Peptides through the Conjugation of FtsZ-Binding and Cell-Penetrating Peptides.

Ruo-Lan Du, Cheung-Hin Hung, Alan Siu-Lun Leung, Kang Ding, Wai-Po Kong, Yong Wang, Zhi-Guang Liang, Pak-Ho Chan, Kwok-Yin Wong.

  The rapid increase in bacterial resistance to conventional antibiotics has led to a great demand for novel antibacterial agents. Antimicrobial peptides (AMPs) are emerging as next-generation antimicrobial alternative drugs to conventional antibiotics because of their broad-spectrum antimicrobial activities and minimal potential for drug resistance induction. This work describes novel antimicrobial peptides (FtsZpcpp) synthesized through the conjugation of a cell penetration peptide ((RXR)4XB) to nonantimicrobial peptides (FtsZp). The FtsZp peptides were previously identified to bind FtsZ (flaming-temperature-sensitive protein Z), a crucial protein in regulating bacterial cell divisions. Newly designed FtsZpcpp peptides have broad antimicrobial activities against both Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. Besides, these new peptides exert minimal hemolytic activity toward human red blood cells and low cytotoxicity toward human skin cells. Comprehensive studies on the antimicrobial mechanism of FtsZpcpp peptides revealed that they exert antimicrobial activities through multiple mechanisms, including membrane disruption and intracellular actions (e.g., interference with cell divisions, DNA binding, and reactive oxygen species (ROS) generation). Our results have shown that FtsZpcpp peptides have the potential to serve as future antimicrobial drugs in combating the increasing global problem of antibiotic resistance.

Keywords:  antibiofilm; antimicrobial peptides; antimicrobial resistance; cell division; cell membrane; cell penetrating peptide

DOI:  https://doi.org/10.1021/acsinfecdis.5c00220
Biochem Biophys Res Commun. 2025 Jul 17. pii: S0006-291X(25)01009-5. [Epub ahead of print]778 152294

Neutral peptides allow aggregation of cationic peptides in antimicrobial secretory fluids.

Peicho Petkov, Rositsa Marinova, Leandar Litov, Petya Sirakova, Elena Lilkova, Kamelia Kamburova, Elena Krachmarova, Stefka Taneva, Frédéric Allemand, Assia Mouhand, Aurélien Thureau, Nathalie Sibille, Nevena Ilieva.

  Antimicrobial peptides (AMPs) are seen as a promising alternative to conventional antibiotics, yet their mechanism of action is not fully understood. We recently proposed that AMPs do not act as isolated monomers but instead aggregate into nano-sized clusters before targeting the membrane. However, cationic peptides may struggle to form clusters large enough to achieve effective membrane disruption alone, suggesting the involvement of a co-actor in this process. Here, we tackle this issue through both in silico and in vitro studies of mono- and bicomponent solutions comprising two newly identified peptides, one charged and the other neutral, before the interaction with the target membrane. We observe that while the charged peptides alone do not form clusters of noticeable size, in the mixture with the neutral peptides they coalesce into layered aggregates with a hydrophobic core of the neutral moiety and the charged monomers exposed to the surrounding solvent. The size of these mixed charged/neutral peptides aggregates is smaller than the ones in the neutral monocomponent solution due to the counteraction of electrostatic repulsion to the hydrophobic effect. We regard the structures thus formed as an ideal transport system - locking hydrophobic uncharged residues in the cluster core prevents interaction with eukaryotic membranes, while solvent-exposed charged residues facilitate electrostatic interaction with bacterial surfaces.

Keywords:  Circular dichroism; Dynamic light scattering; Local concentration; Molecular modeling; Peptide self-association; Peptide transport; Small-angle X-ray scattering; Solvation behavior; Transmission electron microscopy

DOI:  https://doi.org/10.1016/j.bbrc.2025.152294