This study aimed to validate the inhibitory effect and mechanism of a yak bone collagen-derived antioxidant peptide (GGGPGPM, named P1) against skin photoaging. A murine skin photoaging model induced by UV irradiation was established and topically treated with hydrogel containing different concentrations of P1. The anti-photoaging effects of P1 were evaluated through skin macroscopic observation, hydration and histological analysis, collagen content determination, and antioxidant enzyme detection. Furthermore, the key protein expression of the Keap1/Nrf2 signaling pathway and the composition of skin microbiota were analyzed by western blotting and amplicon sequencing. After intervention with P1, the collagen content and the activity of antioxidant enzymes in the skin of mice subjected to UV irradiation were significantly improved. Western blot analysis revealed that the high-dose P1 group exhibited 1.75-, 1.90-, and 2.72-fold increases in the expression levels of Nrf2, HO-1, and NQO1 compared to the model group, respectively. Additionally, P1 intervention significantly modulated the skin microbiota structure. At the phylum level, the high-dose P1 intervention elevated the abundance of Firmicutes and reduced the abundance of Actinobacteria, which might be mainly attributed to the rise of Staphylococcus and the decline of Corynebacterium. Specially, there was no significant difference observed between the high-dose P1 group and the blank control group in the composition of skin microbiota. Collectively, P1 might ameliorated UV-induced skin photoaging in mice by activating the Keap1/Nrf2 signaling pathway and restructuring skin microbiota.
Pulmonary fibrosis (PF) is a challenging interstitial lung disease with limited therapeutic options. This study explores the therapeutic effects of alamandine (ALA), a renin-angiotensin system peptide, in reversing established fibrotic progression in an experimental model. Male Wistar rats were divided into four groups (n = 5–6/group): control (CO), ALA-treated (ALA), bleomycin-induced fibrosis (BLM), and bleomycin plus ALA treatment (BA). Fibrosis was induced by intratracheal bleomycin (2.5 mg/kg) on day 0. Subcutaneous ALA treatment (50 µg/kg/day) began on day 10 and continued until day 19. Respiratory mechanics, body weight, Ashcroft score, and lung transforming growth factor-beta (TGF-β) content were evaluated. Plasma RAS peptides were quantified by LC-MS/MS. Bleomycin significantly increased respiratory resistance (CO = 0.104 ± 0.026 vs. BLM = 0.159 ± 0.047 cmH₂O.s/mL in CO, p < 0.008) and Ashcroft score, and reduced body weight gain. ALA treatment from day 10–20 markedly improved body weight gain (p < 0.001), reduced Ashcroft score (BLM = 2.23 ± 0.35 vs. BA = 1.21 ± 0.40, p < 0.0001), and decreased lung TGF-β1 content (BLM = 3.70 ± 1.7 vs. BA = 1.10 ± 0.42 pg/mg protein, p < 0.0015). These results were associated with qualitatively improved respiratory effort, suggesting attenuation of bleomycin-induced fibrogenesis. Despite rapid tissue uptake, late ALA treatment was associated with reduced histological fibrosis, lower TGF-β1 content, and improved selected functional and clinical indicators in rats with established pulmonary fibrosis. These findings suggest a potential therapeutic benefit that warrants further dose- and time-ranging studies.
Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease lacking effective pharmacotherapy. Oxidative stress drives AAA progression, yet conventional antioxidant strategies show limited efficacy. The gut microbiota regulates host redox homeostasis, but its role in AAA remains unclear. Using gut metagenomic data from AAA patients, experimental AAA mouse models and an in vitro oxidative injury model, we investigated the role and underlying mechanisms of the gut microbiota-associatedmetabolite γ-glutamylcysteine (γ-GC) in AAA. The abundance of key γ-GC biosynthesis genes, as well as intestinal and circulating γ-GC levels were significantly reduced in AAA patients, negatively correlating with oxidative stress markers and aneurysm diameter. Oral γ-GC supplementation improved intestinal barrier integrity, reduced plasma lipopolysaccharide (LPS) levels, and suppressed aneurysm expansion and elastic fiber degradation. Furthermore, γ-GC alleviated oxidative stress in plasma and aneurysmal tissues, whilst reducing vascular smooth muscle cell (VSMC) apoptosis, macrophage infiltration, and the expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and matrix metalloproteinases (MMP2, MMP9). Mechanistically, γ-GC upregulated Polo-like kinase 1(Plk1) expression and inhibited reactive oxygen species (ROS)-induced VSMC apoptosis and pro-inflammatory cytokine expression. Notably, γ-GC modulated the spatial distribution of Plk1 and G3BP1, thereby attenuating ROS-induced G3BP1 condensation and promoting the disassembly of pathological stress granules. The gut microbiota-associatedmetabolite γ-GC is negatively correlated with AAA severity. γ-GC supplementation ameliorates AAA through restoring redox homeostasis and suppressing pathological stress granule formation. While the functional link between Plk1 and G3BP1 condensation requires further investigation, our findings suggest thatγ-GC represents a promising therapeutic candidate for early pharmacological intervention in AAA.
This research aims to identify novel antimicrobial peptides (AMPs) from casein, subsequently conducting an in-depth exploration of their antibacterial mechanism of action. Casein was hydrolyzed by pepsin and fractionated via ultrafiltration, and the peptides were identified using Nano-LC-MS/MS. Then, the candidate antimicrobial peptides were screened based on in silico analysis of their antimicrobial potential, net charge, and solubility. The minimum inhibitory concentration (MIC) against E. coli ATCC 25922 was determined, and killing kinetics was analyzed. The effect on bacterial membrane integrity was assessed through the analysis of nucleic acid leakage, outer membrane permeability, inner membrane permeability, and cell membrane damage. Preliminary safety was evaluated via hemolytic activity and impact on L. acidophilus CICC 6074 and L. reuteri DSM 17938 growth. Two peptides, VRYL and RYL, were successfully identified from bovine casein hydrolysate. Both demonstrated potent inhibitory activity against E. coli ATCC 25922. VRYL exhibited a MIC of 3.5 mg/mL, which was lower than RYL’s MIC of 5.5 mg/mL. This indicates that VRYL possesses stronger inhibitory activity against E. coli compared to RYL. The antimicrobial mechanism of VRYL was analyzed and revealed that it exerts its antimicrobial activity by compromising the integrity of both the outer and inner bacterial membranes. Furthermore, VRYL exhibited favorable preliminary safety with no observable significant hemolytic activity. The peptide VRYL possesses high antimicrobial activity and favorable preliminary safety characteristics. These findings suggest that VRYL holds substantial promise for utilization in the food industry and as a natural antimicrobial agent.
Advanced glycation end products (AGEs) and their downstream inflammatory consequences contribute to skin dysfunction and aging-related deterioration. EQ-9 has been identified as a novel functional peptide with anti-aging and skin repair potential. In this study, we investigated the effects of EQ-9 and its two derivatives (EL-6 and ac EL-6) on Methylglyoxal (MGO)-induced glycation and inflammatory damage. We exposed HaCaT cells to MGO to simulate hyperglycemic conditions. The protective effects of these peptides were assessed through measurements of cell viability, migration, CML levels, inflammatory cytokine secretion, RAGE expression, and NF-κB pathway activation. Additionally, TNF-α/IFN-γ were used to induce inflammatory injury and evaluate the anti-inflammatory effectiveness of the peptides. A murine excision wound model was also established to examine the effects of ac EL-6 on skin inflammation, collagen deposition, angiogenesis, and wound healing. All three peptides significantly reduced MGO-induced CML generation, downregulated RAGE, inhibited NF-κB activation, attenuated proinflammatory cytokine secretion, alleviated cell damage, and promoted migration. They also mitigated TNF-α/IFN-γ-evoked inflammatory responses via NF-κB suppression. Topical application of ac EL-6 decreased cytokine levels, increased VEGF expression and collagen deposition, and consequently accelerated wound healing in mice. Together, these findings identify ac EL-6 as a stabilized lead candidate derived from EQ-9, which exhibits anti-glycation activity and modulates NF-κB-mediated inflammatory signaling in keratinocytes, and demonstrates initial skin-repair potential in vivo. The data support further development of ac EL-6 for skin-directed applications.
Peptides are versatile building blocks for nanomaterials. Their self-assembled hydrogels feature tunable properties and good biocompatibility, enabling applications in cell culture, tissue engineering, and drug delivery. Peptide self-assembly arises from the synergy of multiple noncovalent interactions; among them, π–π stacking between aromatic residues is widely considered to be associated with ordered assembly in aromatic peptides. Eight aromatic heptapeptides containing a “-Y-F-F-” motif were designed to examine how subtle variations in side-chain hydrophobicity correlate with self-assembly and gelation behaviors commonly attributed to aromatic stacking. Fluorescence and FT-IR results indicated that replacing Gly with the slightly bulkier and more hydrophobic Ala between two Phe residues is associated with more ordered networks, and only AA, GA, Fmoc-AA, and Fmoc-GA formed hydrogels under the tested conditions. And TEM/AFM and rheological measurements further revealed qualitative differences in nanofiber morphologies and sequence-dependent self-healing behavior among these gels. As a proof of concept, AA and GA gels exhibited low cytotoxicity, and their DOX-loaded gels displayed pH-responsive release. Notably, A-DOX showed a 66.91
Oxidative stress-induced erythrocyte damage is closely associated with membrane disruption, hemolysis, and impaired cellular antioxidant defense. Silybum marianum protein hydrolysate peptides (NPH) have shown potential antioxidant activity; however, their protective effects against oxidative damage in erythrocytes remain unclear. The protective effects of NPH against 2,2′-azobis(2-methylpropionamidine) dihydrochloride (AAPH)-induced oxidative damage in erythrocytes were investigated. The effects of NPH on hemolysis, erythrocyte morphology, reactive oxygen species (ROS) production, malondialdehyde (MDA) accumulation, antioxidant enzyme activities, and glutathione (GSH)/oxidized glutathione (GSSG)balance were evaluated. NPH exhibited no significant hemolytic effect at concentrations of 0–3.2 mg/mL and significantly reduced AAPH-induced erythrocyte hemolysis in a concentration-dependent manner. The hemolysis rate decreased from 61.02
Chronic and infected wounds represent a major clinical challenge due to prolonged healing times, high treatment costs, and rising antimicrobial resistance. Antimicrobial peptides (AMPs) offer promising alternatives to conventional antibiotics; however, their clinical translation has been limited by poor stability, high production cost, and potential cytotoxicity. This study aimed to evaluate the in vivo wound-healing efficacy and safety of R2W2L, a short, machine learning-designed antimicrobial peptide previously validated for potent anti-staphylococcal activity and favorable biocompatibility. R2W2L (200 µM) ± vitamin D₃ ointments with natural penetration enhancers were applied daily to rat excisional wounds (n = 7/group, 10 days). Closure monitored macroscopically; histology blindly scored. In vitro MIC, cytotoxicity, and hemolysis assessed. All formulations exhibited low cytotoxicity (> 90
Heterocyclic structures play a pivotal role in the realm of medicinal chemistry. We synthesized amino acid derived 2-amino-1,3,4-oxadiazoles and 2-amino-1,3,4-thiadiazoles using Fmoc chemistry. All the synthesized compounds were characterized using NMR spectroscopy and mass spectrometry. Agar well diffusion assays revealed that compound 5f exhibited the highest antibacterial activity against E. coli with a zone of inhibition of 10.20 ± 0.33 mm, while 5e was most effective against Bacillus sp. with a zone of inhibition of 9.70 ± 0.32 mm. Streptomycin served as the positive control with the highest activity. Antifungal assay revealed 5a was most effective against Aspergillus sp., 8.25 ± 0.26 mm and Fusarium sp., 8.05 ± 0.25 mm; other samples showed minimal activity, 6.00 mm. The docking analysis was performed for all the synthesized compounds against the RAP protein of Escherichia coli and Aspergillus niger endoglucanase, which revealed potential antibacterial and antifungal activity. Compound 5e showed the highest binding affinity (−9.7 kcal/mol) and interacted with multiple amino acids, indicating a complex binding mechanism.
Pancreatic cancer remains one of the most challenging malignancies due to limited therapeutic options and poor prognosis, highlighting the need for novel and biocompatible therapeutic strategies. Bacteriocins, natural bioactive peptides produced by lactic acid bacteria, have recently attracted attention due to their potential anticancer and antimicrobial properties; however, their clinical application is limited by instability and poor bioavailability. Bacteriocin produced by Lactobacillus plantarum was encapsulated into chitosan nanoparticles (BC-CSNPs) using the ionic gelation method to improve stability and biological activity. The prepared nanoparticles were characterized using SEM, AFM, FTIR, and XRD analyses. The physicochemical characterization revealed successful bacteriocin incorporation into the chitosan matrix, with an increase in particle size from approximately 59 nm for chitosan nanoparticles (CSNPs) to 98 nm for BC-CSNPs, accompanied by increased surface roughness and reduced crystallinity indicating peptide–polymer interaction. The biological activity of the developed nanocomposite demonstrated enhanced antibacterial activity compared with free bacteriocin and CSNPs alone, suggesting improved peptide stability and delivery efficiency. Furthermore, cytotoxic evaluation against Capan-2 pancreatic cancer cells showed a concentration-dependent reduction in cell viability following BC-CSNPs treatment, with stronger anticancer activity compared with CSNPs alone. The enhanced cytotoxic effect was attributed to the combined activity of bacteriocin and the chitosan nanoparticle delivery system, which may improve cellular interaction and bioavailability. Overall, the findings demonstrate that bacteriocin-loaded chitosan nanoparticles represent a promising multifunctional nano-delivery platform with potential applications in pancreatic cancer therapy. This study provides new insight into the use of lactic acid bacteria-derived bacteriocins beyond antimicrobial applications toward cancer-targeted nanotherapeutic approaches.
Bioactive peptides from dry-cured ham have attracted interest as potential antioxidant ingredients. However, the specific contribution of dipeptides to this activity remains poorly characterized. In this study, we evaluated the safety and antioxidant capacity of ten synthesized dipeptides previously identified in a digested extract from dry-cured ham. Dipeptides were combined according to their relative proportion to obtain a stock solution (10 mg/mL), from which concentrations between 0.125 and 2.5 mg/mL were tested. Cell viability was evaluated in human colorectal Caco-2 cells using the MTT assay. Ex vivo antioxidant activity was determined in Caco-2 and human endothelial EA.hy926 cells, by quantifying reactive oxygen species (ROS) and antioxidant gene expression through directed transcriptomics. In vivo antioxidant activity was evaluated in Caenorhabditis elegans subjected to acute and chronic oxidative stress conditions. The dipeptide fraction maintained > 90
Viperid venoms are difficult to neutralize; up to 19 antivenom vials may be used for severe snake envenomation, so new adjuvants may improve the efficacy of antivenoms. This work aims to utilize chitosan nanoparticles as an immunoadjuvant for the development of neutralizing antibodies against four viperid venoms from the species Lachesis acrochorda (La), Bothrops asper (Bas), Bothrops ayerbei (Bay), and Bothrops rhombeatus (Br), which are of medical importance in Colombia. Chitosan nanoparticles were loaded with four viper venoms and encapsulated via ionic gelation for use as an immunoadjuvant. Chromatography, electron microscopy, polydispersity index, and infrared spectroscopy demonstrated the encapsulation of the venoms. Rabbit immunizations were conducted using chitosan encapsulated venoms, and they were found qualitatively to be less harmful than the adjuvant control (incomplete Freund’s and aluminum hydroxide as adjuvants). Although rabbit antibodies obtained with chitosan-venom nanoparticles showed no significant differences in antibody titers (AT50s) compared to the immunization control, they showed slightly better neutralization than the control group. Encapsulating chitosan nanoparticles with viperid venom could be a useful approach and an alternative immunoadjuvant for enhancing neutralizing antibodies.
Selective removal of antibodies from complex biological samples (plasma, cell culture medium) is of high importance. There is an increasing demand for efficient biomimetic ligands that mimic Protein A’s affinity towards antibodies and overcome their limitations. In this study, we have designed 25 peptides based on the interaction between human IgG (hIgG) and Protein A using in silico tools. The peptides, FYRGWV and FYGWV, had displayed the best binding energies of -7.6 and − 7.1 kcal/mol and maintained a stable complex with hIgG for 100 ns (MD simulation studies). A porous aldehyde-functionalized poly(hydroxyethyl methacrylate) (PolyHEMA) monolith was used as the chromatography resin for the peptide’s immobilization via Schiff base chemistry. Both FT-IR spectroscopy and XPS have confirmed the successful immobilization of the peptides on the monolith. The peptide load on the monolith was found to be 1.3 mg/g monolith (BCA assay data). In the presence of near-neutral pH and physiological salt concentration buffer (pH 7.4), FYRGWV and FYGWV showed static hIgG adsorption of 100.78 mg/g and 50 mg/g and negligible non-specific adsorption for HSA ( 2.5 mg/g) and transferrin ( 4.7 mg/g). The primary driving forces of peptide-hIgG interaction are electrostatic, ionic, and hydrophobic. An FYRGWV-PolyHEMA syringe column of 200 µL column volume was successfully fabricated. The captured hIgG was successfully eluted from the column with 85
Umami-active peptides have attracted considerable interest as natural taste-modulating compounds; however, the molecular mechanisms underlying their interactions with the human T1R1/T1R3 umami receptor remain incompletely understood. This study investigated the receptor interaction patterns and functional properties of short acidic dipeptides using an integrated approach combining molecular docking, receptor-based calcium imaging, and instrumental sensory analysis. Twenty-eight previously reported umami peptides were initially screened by molecular docking against human T1R1 and T1R3 receptors. Five candidate peptides showing favorable predicted interactions with the T1R1/T1R3 heterodimer were subsequently evaluated in hT1R1/hT1R3-expressing HEK293T cells using intracellular calcium imaging. Instrumental sensory characterization of selected peptides was further performed using an electronic tongue system. Among the screened peptides, Ala-Asp, Gly-Glu, and Gly-Asp exhibited favorable docking energies toward the T1R1/T1R3receptor complex. Ala-Asp and Gly-Asp induced pronounced receptor-mediated calcium responses, with ΔF/F values comparable to those of L-glutamic acid. Electronic tongue analysis demonstrated that Ala-Asp and Gly-Asp exhibited distinct umami-related signal profiles and higher umami sensor responses than L-glutamic acid. Structural interaction analysis revealed that residues such as SER-146 and VAL-277 were recurrently involved in peptide receptor interactions, suggesting their contribution to ligand binding and receptor activation. These findings demonstrate that short Asp containing dipeptides, particularly Ala-Asp and Gly-Asp, exhibit favorable interactions with the T1R1/T1R3 receptor complex and induce receptor mediated calcium responses. The study further highlights the usefulness of integrating molecular docking, cellular assays, and instrumental sensory analysis for investigating receptor-ligand interactions of umami-active peptides.
Immunochemotherapy is a promising strategy to enhance anticancer efficacy by combining immunomodulatory agents with conventional chemotherapy. Paclitaxel (PAX) is a widely used first-line chemotherapeutic agent for breast cancer, while LTX-315 is an oncolytic peptide with immunomodulatory properties. This study aimed to evaluate whether LTX-315 could potentiate the anticancer activity of paclitaxel in breast cancer models. The combination of LTX-315 and paclitaxel was investigated in murine 4T1 and human MCF-7 breast cancer cell lines. Drug interactions were quantified using the Chou–Talalay method at fixed LTX-315 ratios of 1:2 and 2:1. Dose reduction index (DRI), cell migration, clonogenic survival, apoptotic nuclear morphology, and Annexin V-based apoptosis were assessed. Both 1:2 and 2:1 combinations showed synergistic interactions in MCF-7 cells, with cooperative activity also observed in 4T1 cells. DRI analysis revealed a favorable dose-sparing profile, with values ranging from approximately 4 to 22 at biologically relevant effect levels. Co-treatment with LTX-315 at 5 μM and paclitaxel at 0.25 μM significantly inhibited cell migration and reduced long-term clonogenic survival compared with single agents. Although apoptotic nuclear morphology was enhanced, early Annexin V-positive populations were not significantly increased. LTX-315 potentiates paclitaxel activity through quantitative synergy, dose-sparing effects, and durable inhibition of breast cancer cell growth and migration, primarily via sustained functional growth suppression rather than amplification of early apoptosis.
Gout is based on hyperuricaemia and ligands targeting urate are still of interest for therapy. Here we screened a cyclic peptide phage-display library with a urate-derived BSA conjugate (BSA-Com1), obtained clone level evidence that the selected peptides bind a urate-related epitope and tested a small set of leads in a preliminary animal model. An Ala-Cys-X₈-Cys-Gly-Gly-Gly-Ser cyclic peptide library (recombinant positivity 92.5
This study investigated the anti-melanogenic activity of enzymatically prepared Ejiao peptides (EJPs) and explored their possible mechanisms of action. Cytotoxicity and melanin synthesis inhibition were evaluated in A375 cells. Peptide composition was analyzed by LC-MS/MS, molecular docking was used to predict interactions between peptides and tyrosinase, and transcriptional responses were assessed using Quantitative Gene Plex (QGP) analysis. Selected peptides were synthesized and evaluated for tyrosinase inhibition and melanin synthesis inhibition. EJPs showed no apparent cytotoxicity in A375 cells at concentrations below 1 mg/mL and reduced melanin-associated absorbance at 0.1 to 1.0 mg/mL (p < 0.05–0.001) under the tested conditions. LC-MS/MS identified 50 peptide sequences, of which 37 were consistently detected in three replicate analyses. Six selected peptides showed predicted docking scores below −7 kcal/mol and were subsequently synthesized. These peptides inhibited tyrosinase activity in vitro and reduced melanin-associated absorbance in A375 cells. Molecular docking predicted that the selected peptides interact with residues surrounding the tyrosinase active-site region. QGP analysis showed that PGPIG reduced the transcript levels of MC1R, CREB, SOX10, MITF, TYR, and TYRP1. EJPs and selected peptide sequences may influence melanogenesis through tyrosinase-related interactions and modulation of melanogenesis-associated gene expression. Further studies in highly pigmented and skin-relevant models are needed to validate the underlying mechanisms and application potential of EJPs.
This study focuses on the evaluation of the therapeutic potential of Tetrascorpin-1 (AaTs-1), a tetrapeptide isolated from Androctonus australis hector venom, proposed as a putative formyl peptide receptor 2 (FPR2) antagonist, in a cuprizone-induced murine model of Multiple sclerosis (MS), a chronic autoimmune and inflammatory disease of the central nervous system. Acute demyelination was induced in mice by administering cuprizone (0.2
A chemometric approach using amino acid descriptors was employed to evaluate the effect of various mutations on the aggregation propensity of human calcitonin (hCt), an approved peptide therapeutic. Models based on well-established amino acid descriptors, like z-scores and F scores, explained nearly all of the variance in aggregation propensity. The likelihood of a mutant to aggregate was found to depend largely on hydrophobicity of key residues, although interactions between aromatic residues are also important. Residues within the central core of the peptide were influential, along with specific sites in the C-terminal region. Meanwhile, electrostatic interactions play only a minor role in governing hCt aggregation. In contrast to previous studies, Phe19 and Tyr12 were found not to have a significant impact on aggregation propensity, whereas Phe16 and Phe22 exerted a somewhat larger effect. The importance of specific C-terminal residues on aggregation propensity of hCt has now been delineated. These findings are relevant to the manufacturing and handling of hCt and are also of importance to its clinical utilization. This work could also guide the potential development of new biobetters of human calcitonin.
Excessive melanin production causes various pigmentary disorders, and strategies involving tyrosinase inhibition and antioxidant activity are crucial for regulating this process. In this study, we designed and synthesized CV5, a short head-to-tail cyclic peptide, and evaluated its structural characteristics and biological activity. CV5 exhibited excellent biocompatibility with a purity of over 98
