Active Peptides Research Articles

Development of Ac2-26 Mesoporous Microparticle System as a Potential Therapeutic Agent for Inflammatory Bowel Diseases.

Inflammatory bowel diseases (IBDs) disrupt the intestinal epithelium, leading to severe chronic inflammation. Current therapies cause adverse effects and are expensive, invasive, and ineffective for most patients. Annexin A1 (AnxA1) is a pivotal endogenous anti-inflammatory and tissue repair protein in IBD. Nanostructured compounds loading AnxA1 or its active N-terminal mimetic peptides improve IBD symptomatology. To further explore their potential as a therapeutic candidate, the AnxA1 N-terminal mimetic peptide Ac2-26 was incorporated into SBA-15 ordered mesoporous silica and covered with EL30D-55 to deliver it by oral treatment into the inflamed gut. The systems SBA-Ac2-26 developed measurements revealed self-assembled rod-shaped particles, likely on the external surface of SBA-15, and 88% of peptide incorporation. SBA-15 carried the peptide Ac2-26 into cultured Raw 264.7 macrophages and Caco-2 epithelial cells. Moreover, oral administration of Eudragit-SBA-15-Ac2-26 (200 μg; once a day; for 4 days) reduced colitis clinical symptoms, inflammation, and improved epithelium recovery in mice under dextran-sodium sulfate-induced colitis. The absorption of SBA-15 in gut epithelial cells is typically low; however, the permeable inflamed barrier can enable microparticles to cross, being phagocyted by macrophages. These findings suggest that Ac2-26 is successfully delivered and binds to its receptors in both epithelial and immune cells, aligning with the clinical results. Our findings demonstrate a simple and cost-effective approach to delivering Ac2-26 orally into the inflamed gut, highlighting its potential as non-invasive IBD therapy.

Preparation, identification, and molecular docking of novel angiotensin-converting enzyme inhibitory peptides derived from rice-based distillers' spent cakes.

Rice-based distillers' spent cake (RDSC), a by-product of the Chinese liquor (Baijiu) industry, is a potential source of angiotensin-converting enzyme (ACE) inhibitory peptide. Since ACE plays a crucial role in controlling hypertension, inhibition of ACE has been widely emphasized. The ACE inhibitory active peptide derived from by-products of food has been recognized as a safer and cheaper inhibitor. Aimed to discover ACE-inhibiting active peptides in RDSC. Hydrolysis of RDSC by alcalase for 4 h followed by ultrafiltration yielded low-molecular-weight (< 3 kDa) fractions. Subsequently, a comprehensive method using a combination of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) and LC-Q-Exactive-MS to identify the novel short peptides (3-5 amino acids residues; n = 7) and medium-sized peptides (more than 6 amino acids residues; n = 6). In vitro activity assay showed that the peptides KPFFPGL, GFPRPLL, GPPGVF, and VGK exhibited the highest activity with inhibitory concentration of 50% (IC50) of 11.63, 12.34, 19.55, and 33.54 μmol L-1. Molecular docking reveal that the active and inactive sites (Glu123, Asp121, Arg522, and Lys118) play important roles in enhancing the ACE inhibitory activity of peptides. Here we report a comprehensive method that effectively extracted and identified the bioactive peptides from RDSC. Four highly active novel peptides may be the most promising candidates for functional foods against hypertension, provide significant information for enhancing value of rice-based distilled by-products. © 2024 Society of Chemical Industry.

Expression of Multicopy Tandem Recombinant Ginseng Hexapeptide in Bacillus subtilis and the Evaluation of Antiaging Activity.

Ginseng oligopeptides are naturally occurring small-molecule peptides extracted from ginseng that exhibit positive effects on health and longevity. However, the current industrial production of ginseng oligopeptides primarily relies on plant extraction and chemical synthesis. In this study, we proposed a novel genetic engineering approach to produce active ginseng peptides through multicopy tandem insertion (5 and 15 times). The recombinant ginseng peptides were successfully produced from engineered Bacillus subtilis with an increasing yield from 356.55 to 2900 mg/L as the repeats multiple. Additionally, an oxidative stress-induced aging model caused by H2O2 was established to evaluate whether the recombinant ginseng peptides, without enzymatic hydrolysis into individual peptides, also have positive effects on antiaging. The results demonstrated that all two kinds of recombinant ginseng peptides could also delay cellular aging through various mechanisms, such as inhibiting cell cycle arrest, suppressing the expression of pro-inflammatory factors, and enhancing cellular antioxidant capacity.

Antioxidant potential and protective effect of modified sea cucumber peptides against H2O2-induced oxidative damage in vitro HepG2 cells and in vivo zebrafish model

In this study, modified sea Cucumber Peptides (SCP) were prepared by reacting with xylooligosaccharide (XOS) and alginate oligosaccharides (AOS) via glycation. Free radical inhibitory and inhibition of oxidative stress of modified SCP was evaluated using human hepatocellular carcinoma (HepG2) cells and zebrafish embryos.LC-MS analysis revealed that SCPs mainly consist of 40 active peptides, with an average molecular weight of 1122.168 Da and an average length of 11 amino acid residues. For amino acid composition, L-Asparagine, L-Methionine, and L-Aspartic Acid were dominant amino acids in SCP.The result showed that the antioxidant ability of SCP against 2,2-Diphenyl-1-picrylhydrazyl (DPPH), superoxide anion radical (O−2), and Hydroxyl Radical (OH) was significantly improved after modification. In HepG2 cells, the modified SCP showed stronger protection than native SCP native against H2O2-induced oxidative stress by enhancing cell viability and reducing radical oxygen species (ROS) generation. The inhibition effect of SCP was increased after modification with XOS and AOS by 13 % and 19 % respectively. Further studies displayed that the activity of antioxidative enzymes, including Superoxide dismutase (SOD), Glutathione Peroxidase (GPx), and catalase (CAT), was remarkably enhanced, whereas malondialdehyde (MDA) level was reduced compared with native SCP and H2O2-treated groups, thus, improving the intracellular antioxidant defenses. The gene expression analysis showed that the mechanism underlying the modified SCP protective effect may be linked with the capability to regulate Nuclear factor-erythroid factor 2-related factor 2 (NRF2) gene expression. The protective effect of modified SCP against H2O2 in vitro was confirmed in vivo by reduced toxicity in zebrafish embryos via improvement of mortality rate, hatching rate, heart beating rate, and deformities of the zebrafish model. However, SCPAOS conjugate displayed greater antioxidant potentials compared to the SCPXOS, the different effects between SCPAOS and SCPXOS could be due to their different antioxidant activity. Thus, modified SCP could be potentially used as a novel nutraceutical in the preparation of anti-aging food and medicine.

Exploration of anti-osteoporotic peptides from Moringa oleifera leaf proteins by network pharmacology, molecular docking, molecular dynamics and cellular assay analyses

Moringa oleiferaleaf peptide, which is a plant-derived bioactive peptide, exhibits several advantages, including safety, high efficiency and nontoxic side effects. The goal of this study was to identify representative antiosteoporotic peptides fromMoringa oleiferaleaf proteins and determine their regulatory mechanisms using network pharmacology, molecular docking and molecular dynamics. The following core targets of Moringa oleifera leaf antiosteoporotic peptides were screened by network pharmacology: SRC, MAPK1, JUN and STAT3. Through molecular docking, DPYLGK was identified as a representative active peptide from the Moringa oleifera leaf protein, and SRC was determined to be a potential primary target. Molecular dynamics revealed the intermolecular mechanism of DPYLGK and SRC. Cellular assays showed that DPYLGK promotes bone formation and inhibits bone resorption. These findings demonstrated that DPYLGK is an anti-osteoporotic peptide with dual regulatory effects and will aid in the development of functional foods to prevent osteoporosis.

A mouse model of the protease-activated receptor 4 Pro310Leu variant has reduced platelet reactivity

BackgroundProtease-activated receptor 4 (PAR4) mediates thrombin signaling on platelets and other cells. Our recent structural studies demonstrated that a single nucleotide polymorphism in extracellular loop 3 and PAR4-P310L (rs2227376) leads to a hyporeactive receptor. ObjectivesThe goal of this study was to determine how the hyporeactive PAR4 variant in extracellular loop 3 impacts platelet function in vivo using a novel knock-in mouse model (PAR4-322L). MethodsA point mutation was introduced into the PAR4 gene F2rl3 via CRISPR/Cas9 to create PAR4-P322L, the mouse homolog to human PAR4-P310L. Platelet response to PAR4 activation peptide (AYPGKF), thrombin, ADP, and convulxin was monitored by αIIbβ3 integrin activation and P-selectin translocation using flow cytometry or platelet aggregation. In vivo responses were determined by the tail bleeding assay and the ferric chloride–induced carotid artery injury model. ResultsPAR4-P/L and PAR4-L/L platelets had a reduced response to AYPGKF and thrombin measured by P-selectin translocation or αIIbβ3 activation. The response to ADP and convulxin was unchanged among genotypes. In addition, both PAR4-P/L and PAR4-L/L platelets showed a reduced response to thrombin in aggregation studies. There was an increase in the tail bleeding time for PAR4-L/L mice. The PAR4-P/L and PAR4-L/L mice both showed an extended time to arterial thrombosis. ConclusionPAR4-322L significantly reduced platelet responsiveness to AYPGKF and thrombin, which is in agreement with our previous structural and cell signaling studies. In addition, PAR4-322L had prolonged arterial thrombosis time. Our mouse model provides a foundation to further evaluate the role of PAR4 in other pathophysiological contexts.

Optimization of Hydrolysis Conditions, Isolation, and Identification of Biologically Active Peptides Derived from Acheta domesticus for Antioxidant and Collagenase Inhibition.

The study aimed to optimize hydrolysis conditions and isolate and identify bioactive peptides with anti-skin aging effects from Acheta domesticus (house cricket). A. domesticus proteins underwent hydrolysis using Alcalase® and optimized conditions using response surface methodology through a face-centered central composite design. Variable controls (enzyme-substrate concentration (E/S), time, and temperature) were assessed for their impact on activities against collagenase, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH●), and degree of hydrolysis of protein hydrolysate (PH). PH was also investigated for composition, anti-skin aging, and anti-inflammatory effects. Amino acid sequences with potent anti-skin aging activity were isolated and identified using ultrafiltration, gel filtration chromatography, and liquid chromatography coupled with tandem mass spectrometry, employing de novo sequencing. Optimal conditions for producing PH with maximum anti-skin aging activity were an E/S concentration of 2.1% (w/w), 227 min, and 61.5 °C. Glutamic acid was a predominant amino acid and PH exhibited a molecular weight below 15 kDa. Additionally, PH displayed significant activities against collagenase, hyaluronidase, DPPH●, lipid peroxidation, and NF-κB-mediated inflammation (p < 0.05). Three novel anti-skin aging peptides were identified-Ala-Val-Thr-Lys-Ala-Asp-Pro-Tyr-Thr-Asp-Gln, Thr-Val-Met-Glu-Leu-Asn-Asp-Leu-Val-Lys-Ala-Phe, and Val-Pro-Leu-Leu-Glu-Pro-Trp-exhibiting the most potent collagenase and DPPH● inhibition. Therefore, this study proposed that PH, produced with Alcalase® under optimal conditions, emerges as a promising substance with potent anti-skin aging activity for the cosmeceutical industry.

Antimicrobial peptides designed by computational analysis of proteomes.

Antimicrobial peptides (AMPs) are promising cationic and amphipathic molecules to fight antibiotic resistance. To search for novel AMPs, we applied a computational strategy to identify peptide sequences within the organisms' proteome, including in-house developed software and artificial intelligence tools. After analyzing 150.450 proteins from eight proteomes of bacteria, plants, a protist, and a nematode, nine peptides were selected and modified to increase their antimicrobial potential. The 18 resulting peptides were validated by bioassays with four pathogenic bacterial species, one yeast species, and two cancer cell-lines. Fourteen of the 18 tested peptides were antimicrobial, with minimum inhibitory concentrations (MICs) values under 10µM against at least three bacterial species; seven were active against Candida albicans with MICs values under 10µM; six had a therapeutic index above 20; two peptides were active against A549 cells, and eight were active against MCF-7 cells under 30µM. This study's most active antimicrobial peptides damage the bacterial cell membrane, including grooves, dents, membrane wrinkling, cell destruction, and leakage of cytoplasmic material. The results confirm that the proposed approach, which uses bioinformatic tools and rational modifications, is highly efficient and allows the discovery, with high accuracy, of potent AMPs encrypted in proteins.

Effect of bi-enzyme hydrolysis on the properties and composition of hydrolysates of Manchurian walnut dreg protein

Walnut dreg (WD) active peptides are an important source of dietary antioxidants; however, the products of conventional hydrolysis have limited industrial output owing to poor flavour and low bioactivity. To this end, in this study, we aimed to employ bvLAP, an aminopeptidase previously identified in our research, as well as commercially available Alcalase for bi-enzyme digestion. The flavour, antioxidant activity, and structures of products resulting from various digestion methods were compared. The results showed that the bi-enzyme digestion products had enhanced antioxidant activity, increased β-sheet content, and reduced bitterness intensity from 9.65 to 6.93. Moreover, bi-enzyme hydrolysates showed a more diverse amino acid composition containing 1640 peptides with distinct sequences. These results demonstrate that bi-enzyme hydrolysis could be a potential process for converting WD into functional food ingredients. Additionally, our results provide new concepts that can be applied in waste processing and high-value utilisation of WD.

Peptide derived from RAGE efficiently improves oocyte development through attenuating oxidative stress in oocytes of mice with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a common and complex endocrine disorder in reproductive-aged women that frequently leads to infertility due to poor oocyte quality. In this study, we identified a new active peptide (advanced glycation end products receptors RAGE344-355 ) from PCOS follicular fluid using mass spectrometry. We found that supplementing PCOS-like mouse oocytes with RAGE344-355 attenuated both meiotic defects and oxidative stress levels, ultimately preventing developmental defects. Additionally, our results suggest that RAGE344-355 may interact with eEF1a1 to mitigate oxidative meiotic defects in PCOS-like mouse oocytes. These findings highlight the potential for further clinical development of RAGE344-355 as a potent supplement and therapeutic option for women with PCOS. This research addresses an important clinical problem and offers promising opportunities for improving oocyte quality in PCOS patients.

SRAGE-binding and antimicrobial bioactivities of soy and pea protein after heating and in vitro infant digestion

During infant formula production, proteins are always heated, potentially affecting their digestibility and the bioactivities of resulting peptides. Although plant proteins are a promising dairy alternative for infant formula, they remain understudied, necessitating further investigations. Therefore, this research aimed to fill this gap by assessing the impact of different heating modes on soy protein (SP) and pea protein (PP), focusing on glycation levels, peptide formation during in vitro infant digestion, and immune protection potential (sRAGE-binding and antimicrobial activities) of the resulting peptides. Consequently, dry heating led to increased glycation and glycated peptide production, particularly with higher glycation in PP than SP. Moreover, PP exhibited an overall stronger sRAGE-binding capacity than SP, regardless of heating and digestion conditions. Regarding antimicrobial activity, both SP and PP-derived peptides displayed reduced effectiveness against Enterobacter cloacae after dry heating. Additionally, Staphylococcus epidermidis was differently inhibited, where PP-derived peptides showed inherent inhibition. The primary determinant of sRAGE-binding and antimicrobial potential in digestion-derived peptides was the protein source. Subsequent bioinformatics analysis predicted 519 and 133 potential antimicrobial peptides in SP and PP, respectively. This study emphasises the importance of protein source for infant formula to ensure infant health.

Exploration of hypoglycemic peptides from porcine collagen based on network pharmacology and molecular docking.

In recent years, the extraction of hypoglycemic peptides from food proteins has gained increasing attention. Neuropeptides, hormone peptides, antimicrobial peptides, immune peptides, antioxidant peptides, hypoglycemic peptides and antihypertensive peptides have become research hotspots. In this study, bioinformatic methods were used to screen and predict the properties of pig collagen-derived hypoglycemic peptides, and their inhibitory effects on α-glucosidase were determined in vitro. Two peptides (RL and NWYR) were found to exhibit good water solubility, adequate ADMET (absorption, distribution, metabolism, elimination, and toxicity) properties, potentially high biological activity, and non-toxic. After synthesizing these peptides, NWYR showed the best inhibitory effect on α-glucosidase with IC50 = 0.200±0.040 mg/mL, and it can regulate a variety of biological processes, play a variety of molecular functions in different cellular components, and play a hypoglycemic role by participating in diabetic cardiomyopathy and IL-17 signaling pathway. Molecular docking results showed that NWYR had the best binding effect with the core target DPP4 (4n8d), with binding energy of -8.8 kcal/mol. NWYR mainly bonded with the target protein through hydrogen bonding, and bound with various amino acid residues such as Asp-729, Gln-731, Leu-765, etc., thus affecting the role of the target in each pathway. It is the best core target for adjuvant treatment of T2DM. In short, NWYR has the potential to reduce type 2 diabetes, providing a basis for further research or food applications as well as improved utilization of pig by-products. However, in subsequent studies, it is necessary to further verify the hypoglycemic ability of porcine collagen active peptide (NWYR), and explore the hypoglycemic mechanism of NWYR from multiple perspectives such as key target genes, protein expression levels and differences in metabolites in animal models of hyperglycemia, which will provide further theoretical support for its improvement in the treatment of T2DM.

Roasted yerba mate (Ilex paraguariensis) infusions in bovine milk model before and after in vitro digestion: Bioaccessibility of phenolic compounds, antioxidant activity, protein–polyphenol interactions and bioactive peptides

Yerba mate is increasingly acknowledged for its bioactive properties and is currently being incorporated into various food and pharmaceutical products. When roasted, yerba mate transforms into mate tea, consumed as a hot aqueous infusion, and has gained popularity. This study investigated the bioaccessibility of phenolic compounds, protein–polyphenol interactions, antioxidant activity, and bioactive peptides in roasted yerba mate infusions, utilizing whole, semi-skimmed, and skimmed bovine milk models. The phytochemical profile of roasted yerba mate was analyzed in infusions with water and milk (whole, semi-skimmed, and skimmed), before and after in vitro digestion, identifying 18 compounds that exhibited variations in composition and presence among the samples. Bioavailability varied across different milk matrices, with milk being four times more efficient as a solvent for extraction. Gastric digestion significantly impacted (p < 0.05) the release of phenolic compounds, such as chlorogenic acid and rutin, with only chlorogenic acid remaining 100 % bioavailable in the infusion prepared with skimmed milk. Protein-polyphenol interaction did not influence protein digestion in different infusions, as there was a similarity in the hydrolysis pattern during the digestive process. Changes in antioxidant activity during digestion phases, especially after intestinal digestion in milk infusions, were related to alterations in protein structures and digestive interactions. The evaluation of total phenolic compounds highlighted that skimmed milk infusion notably preserved these compounds during digestion. Peptidomic analysis identified 253, 221, and 191 potentially bioactive peptides for whole, semi-skimmed, and skimmed milk-digested infusions, respectively, with a focus on anti-inflammatory and anticancer activities, presenting a synergistic approach to promote health benefits. The selection of milk type is crucial for comprehending the effects of digestion and interactions in bioactive compound-rich foods, highlighting the advantages of consuming plant infusions prepared with milk.

A Novel Ophthalmic Solution Containing Glicopro® Complex for the Treatment of Patients with Dry Eye Disease: Results from a Pilot Study.

(1) Background: Dry eye disease (DED) is a multifactorial ocular surface disease characterized by an imbalance in ocular surface homeostasis, and tear substitutes constitute the first line of treatment. The present study aimed to evaluate the changes in the signs and symptoms of patients with DED treated with a novel tear substitute containing the GlicoPro® complex. (2) Methods: Patients with DED not successfully responding to other tear substitutes were enrolled and treated with a novel ophthalmic solution (two drops four times daily). Patients were examined before starting the study treatment (T0) and after 30 (T1) and 60 (T2) days of treatment by means of Keratograph for the evaluation of the following: (i) tear meniscus height (TMH); (ii) noninvasive Keratograph break-up time (NIKBUT); (iii) bulbar redness; and (iv) infrared meibography. The SANDE questionnaire was administered to assess ocular discomfort symptoms. Analysis of the tear content of proenkephalin and Met/Leu-enkephalin was also performed. (3) Results: At T2, a significant improvement in NIKBUT first, average, and class, TMH, and SANDE score was found. The tear content of proenkephalins was significantly higher at T1, whereas processed active Met/Leu-enkephalins increased at both T1 and T2. (4) Conclusions: Our novel tear substitute based on GlicoPro® resulted in a significant improvement in ocular discomfort symptoms, tear volume, and stability in the patients treated. The increase in active peptides processed in tears may represent the pathophysiological substrate underlying this finding.

Efficacy and potential mechanism of atherosclerosis prevention by the active components of leech based on network pharmacology combined with animal experiments

IntroductionLeeches are flesh-eating and bloodsucking parasitic worms. They are being used as a traditional Chinese medicine for centuries in activating blood and dissolving statis, dreging the meridims and tick. Hirudin, an active peptide product present in leech, has blood anticoagulant property and can assist in the treatment of thrombosis and diseases related to blood circulation. The efficacy and potential mechanism of action of leeches in such diseases should be further explored. Materials and methodsFirst, network pharmacology was used to screen the predicted potential targets of the active constituents of leech and AS. The common targets of the active constituents of leech and AS were obtained using Venn diagram. Further, the drug-active-constituent–target network diagram, protein–protein interaction, and GO and KEGG pathway enrichment analyses were used to construct the active-constituent–AS target–pathway network diagram. Subsequently, the protein–drug molecule docking model was drawn. Finally, the results of network pharmacology were validated using a mouse model of AS. ResultsIn total, 34 active constituents of leech and 1172 AS-related gene targets were selected, took the drug action targets and potential disease targets to get the common targets, and took the top 10 of degree value as the main active constituents for the treatment of atherosclerosis. There were 89 common targets and 12 core targets. The main targets included MAPK, EGFR, PIK3CB, etc. Potential regulatory pathways included cancer pathways, EGFR tyrosine kinase inhibitor resistance, Rap1 signaling pathway, PPAR signaling pathway, PI3K-Akt signaling pathway, C-type lectin receptor signaling pathway, and AGE-RAGE signaling pathway in diabetic complications. Animal experiments using mouse model of AS confirmed that AS plaques were smaller after treatment with leeches. SRC level was measured using western blotting. Expression of SRC in myocardial tissue was remarkably lower in the mice treated with leech than in the mice from model group fed on high-fat chow. ConclusionsTo the best of our knowledge, this is the first study to explore the mechanism of action of the active components of leech in AS prevention. The active components of leeches play a coordinated role in preventing AS through multicomponent, multitarget, and multichannel mechanism of action related to inflammatory response, oxidative stress, and lipid metabolism. This study provided a reference for subsequent cellular and animal experiments.

G-ACP: a machine learning approach to the prediction of therapeutic peptides for gastric cancer

Conventional Gastrointestinal (GI) cancer treatments are quite expensive and have major hazards. Nowadays, a different strategy places more emphasis on creating tiny biologically active peptides that do not cause severe poisoning. Anticancer peptides (ACPs) are found through experimental screening, which is time-dependent and frequently fraught with difficulties. Gastric ACPs are emerging as a promising GI cancer treatment in the current day. It is crucial to identify novel gastric ACPs to have an improved knowledge of their functioning processes and treatment of gastric cancer. As a result of the post-genomic era’s massive production of peptide sequences, rapid and effective ACPs using a computational method are essential. Several adaptive statistical techniques for distinguishing ACPs and non-ACPs have recently been developed. A variety of adapted statistically significant methods have been developed to differentiate between ACPs and non-ACPs. Despite significant progress, there is no specific model for the prediction of gastric ACPs because the specific model will predict a particular type of peptide more accurately and quickly. To overcome this, an initiative is taken for the creation of a reliable framework for the accurate identification of gastric ACPs. The current technique in particular contains four possible features along with one hybrid feature encoding mechanisms which are the target-class motif previously indicated by Amino Acid Composition, Dipeptide Composition, Tripeptide Composition (TPC), Pseudo Amino Acid Composition (PAAC), and their Hybrid. Machine Learning algorithms make high-performance and accurate prediction tools. Moreover, highly variable and ideal deep feature selection is done using an ANOVA-based F score for feature pruning. Experiments on a range of algorithms are carried out to identify the optimal operating strategy due to the diverse nature of learning. Following analysis of the empirical results, Naïve Bayes with TPC and Hybrid feature space outperforms other methods with 0.99 accuracy score on the testing dataset. To find the model generalization an external validation is carried out. In external datasets, the Extra Trees with PAAC features outperforms with the accuracy of 0.94. The comparison study shows that our suggested model will predict gastric ACPs more accurately and will be useful in drug development and gastric cancer. The predictive model can be freely accessed at https://github.com/humeraazad10/G-ACP.git. Communicated by Ramaswamy H. Sarma

An in silico scheme for optimizing the enzymatic acquisition of natural biologically active peptides based on machine learning and virtual digestion

BackgroundAs a potential natural active substance, natural biologically active peptides (NBAPs) are recently attracting increasing attention. The traditional proteolysis methods of obtaining effective NBAPs are considerably vexing, especially since multiple proteases can be used, which blocks the exploration of available NBAPs. Although the development of virtual digesting brings some degree of convenience, the activity of the obtained peptides remains unclear, which would still not allow efficient access to the NBAPs. It is necessary to develop an efficient and accurate strategy for acquiring NBAPs. ResultsA new in silico scheme named SSA-LSTM-VD, which combines a sparrow search algorithm-long short-term memory (SSA-LSTM) deep learning and virtually digested, was presented to optimize the proteolysis acquisition of NBAPs. Therein, SSA-LSTM reached the highest Efficiency value reached 98.00 % compared to traditional machine learning algorithms, and basic LSTM algorithm. SSA-LSTM was trained to predict the activity of peptides in the proteins virtually digested results, obtain the percentage of target active peptide, and select the appropriate protease for the actual experiment. As an application, SSA-LSTM was employed to predict the percentage of neuroprotective peptides in the virtual digested result of walnut protein, and trypsin was ultimately found to possess the highest value (85.29 %). The walnut protein was digested by trypsin (WPTrH) and the peptide sequence obtained was analyzed closely matches the theoretical neuroprotective peptide. More importantly, the neuroprotective effects of WPTrH had been demonstrated in nerve damage mouse models. SignificanceThe proposed SSA-LSTM-VD in this paper makes the acquisition of NBAPs efficient and accurate. The approach combines deep learning and virtually digested skillfully. Utilizing the SSA-LSTM-VD based strategy holds promise for discovering and developing peptides with neuroprotective properties or other desired biological activities.

Identification and characterization of antibacterial peptides produced by Lactobacillus plantarum 1407.

Peptides from lactic acid bacteria provide health benefits and can inhibit the growth of pathogenic organisms. The present work aimed to isolate and characterize peptides with antibacterial activity from Lactobacillus plantarum 1407. Peptides were isolated and purified from L. plantarum 1407. The effect of various physiological parameters on the antibacterial activity of the isolated peptides was analyzed. The mode of action of the peptides on indicator organisms was observed using transmission microscopy analysis and flow cytometry analysis. Antibacterial activity and mode of action of peptides isolated from L. plantarum 1407 against gram-positive and gram-negative bacteria have been studied. L. plantarum culture exhibited maximum antibacterial activity at 40 °C, pH 8, and 0.7% salt concentration. The cell-free supernatant (CFS) was concentrated using a 3 kDa ultrafiltration membrane and the peptide fractions (<3 kDa) were further fractionated using Sephadex G-25 gel filtration chromatography. The antibacterial activity of the eluted fractions (F1 to F4) was evaluated using flow cytometry and transmission electron microscopy. F3 fraction exhibited increased antibacterial activity than F1, F2, and F4 fractions against the indicator organisms. Cell membrane damage and leakage of cytoplasmic content of the bacterial cells treated with the antibacterial F3 fraction peptides were observed. The active peptides from L. plantarum 1407 can be potentially used for the treatment of bacterial infections.

Low- and high-load resistance training exercise to volitional fatigue generate exercise-induced appetite suppression

Research on exercise-induced appetite suppression often does not include resistance training (RT) exercise and only compared matched volumes. PurposeTo compare the effects of low-load and high-load RT exercise completed to volitional fatigue on appetite-regulation. Methods11 resistance-trained males (24 ± 2 y) completed 3 sessions in a crossover experimental design: 1) control (CTRL); 2) RT exercise at 30% 1-repetition maximum (RM); and 3) RT exercise at 90% 1-RM. RT sessions consisted of 3 sets of 5 exercises completed to volitional fatigue. Acylated ghrelin, active glucagon-like peptide-1 (GLP-1), active peptide tyrosine (PYY), lactate, and subjective appetite perceptions were measured pre-exercise, 0-, 60-, and 120-min post-exercise. Energy intake was recorded the day before, of, and after each session. ResultsLactate was elevated following both 30% (0-, 60-, 120-min post-exercise) and 90% (0-, 60-min post-exercise; P < 0.001, d > 3.92) versus CTRL, with 30% greater than 90% (0-min post-exercise; P = 0.011, d = 1.14). Acylated ghrelin was suppressed by 30% (P < 0.007, d > 1.22) and 90% (P < 0.028, d > 0.096) post-exercise versus CTRL, and 30% suppressed concentrations versus 90% (60-min post-exercise; P = 0.032, d = 0.95). There was no effect on PYY (P > 0.171, ηp2 <0.149) though GLP-1 was greater at 60-min post-exercise in 90% (P = 0.052, d = 0.86) versus CTRL. Overall appetite was suppressed 0-min post-exercise following 30% and 90% versus CTRL (P < 0.013, d > 1.10) with no other differences (P > 0.279, d < 0.56). There were no differences in energy intake (P > 0.101, ηp2 <0.319). ConclusionsRT at low- and high-loads to volitional fatigue induced appetite suppression coinciding with changes in acylated ghrelin though limited effects on anorexigenic hormones or free-living energy intake were present.

Anionic liposome formulation for oral delivery of thuricin CD, a potential antimicrobial peptide therapeutic

Thuricin CD is a two-peptide antimicrobial produced by Bacillus thuringiensis. Unlike previous antibiotics, it has shown narrow spectrum activity against Clostridioides difficile, a bacterium capable of causing infectious disease in the colon. However, peptide antibiotics have stability, solubility, and permeability problems that can affect their performance in vivo. This work focuses on the bioactivity and bioavailability of thuricin CD with a view to developing a formulation for delivery of active thuricin CD peptides through the gastrointestinal tract (GIT) for local delivery in the colon. The results indicate that thuricin CD is active at low concentrations only when both peptides are present. While thuricin CD was degraded by proteases and was unstable and poorly soluble in gastric fluid, it showed increased solubility in intestinal fluid, probably due to micelle encapsulation. Based on this, thuricin CD was encapsulated in anionic liposomes, which showed increased activity compared to the free peptide, maintained activity after exposure to pepsin in gastric fluid and intestinal fluid, was stable in suspension for over 21 days at room temperature and for 60 days at 4 °C, and exhibited no toxicity to epithelial intestinal cells. These findings suggest that an anionic lipid-based nano formulation may be a promising approach for local oral delivery of thuricin CD.