Short-chain Peptides Research Articles

Characterizing the Flavor Precursors and Liberation Mechanisms of Various Dry-Aging Methods in Cull Beef Loins Using Metabolomics and Microbiome Approaches.

The objective of this study was to characterize and compare the dry-aging flavor precursors and their liberation mechanisms in beef aged with different methods. Thirteen paired loins were collected at 5 days postmortem, divided into four sections, and randomly assigned into four aging methods (wet-aging (WA), conventional dry-aging (DA), dry-aging in a water-permeable bag (DWA), and UV-light dry-aging (UDA)). All sections were aged for 28 days at 2 °C, 65% RH, and a 0.8 m/s airflow before trimming and sample collection for chemical, metabolomics, and microbiome analyses. Higher concentrations of free amino acids and reducing sugars were observed in all dry-aging samples (p < 0.05). Similarly, metabolomics revealed greater short-chain peptides in the dry-aged beef (p < 0.05). The DWA samples had an increase in polyunsaturated free fatty acids (C18:2trans, C18:3n3, C20:2, and C20:5; p < 0.05) along with higher volatile compound concentrations compared to other aging methods (aldehyde, nonanal, octanal, octanol, and carbon disulfide; p < 0.05). Microbiome profiling identified a clear separation in beta diversity between dry and wet aging methods. The Pseudomonas spp. are the most prominent bacterial species in dry-aged meat, potentially contributing to the greater accumulation of flavor precursor concentrations in addition to the dehydration process during the dry-aging. Minor microbial species involvement, such as Bacillus spp., could potentially liberate unique and potent flavor precursors.

Whey protein concentrate mixed beverages and plasma amino acid response in young males

Whey protein isolate (WPI) and whey protein hydrolysate (WPH) contains more protein than whey protein concentrate. However, to achieve a better taste, most commercial products mix WPI and WPH with whey protein concentrate (WPC). This study aimed to compare postprandial blood amino acids following ingestion of three beverages: WPImixed with WPC (WPI-mixed), WPH-mixed with WPI (WPH-mixed), and placebo. A total of ten healthy men aged between 18 and 30, who regularly engaged in exercise training, were recruited as participants. They each received 350 mL of each beverage on separate days and 6-day apart. Concentrations of plasma essential amino acids (EAA), branched-chain amino acids (BCAA), and leucine (Leu) were measured in blood samples taken from participants every 15 mins for 2 hrs. Plasma concentrations of EAA, BCAA, and Leu increased after ingestion of the WPI-mixed and WPH-mixed beverages versus the placebo beverage (P&lt;0.05). Plasma EAA did not differ between WPI- mixed and WPmixed trials. In contrast, plasma concentrations of BCAA after WPI-mixed were higher than after WPH-mixed at 30 mins. The same was observed for Leu at 30 and 75 mins after ingestion. The higher plasma BCAA and Leu in the WPI-mixed trial versus the WPHmixed trial may have been due to the presence of short-chain peptides, as bioactive peptides, in WPH-mixed, which were absorbed. In conclusion, there was no difference in plasma EAA, but plasma concentrations of leucine and BCAA were higher in the WPImixed trial than WPH-mixed trial. Therefore, future research should investigate bioactive peptides along with plasma amino acids.

O-17 - Preclinical assessment of nanoparticles conjugated with 64Cu-DOTA-PEG-BBN targeting gastrin-releasing peptide receptors

1508 Objectives: Gold andiron oxide based nanoparticleshave emerged as innovative tools for cancer imaging and therapy, as benefit of their size, biocompatibility and pharmacokinetics. Their surface functionalization with high number of recognizable biomolecules (gastrin-releasing peptides, GRP, namely bombesin, BBN, bombesin-like short chain peptide, BBN(7-14), and Neuromedin B, NMB) forms high-specific targeted systems, suitable for multimodal PET-MRI or PET-CT imaging aimed for early detection of tumours and/or therapy monitoring and follow-up. The aim of this study was to investigate preclinically and comparatively evaluate the potential as imaging agents of activated N-Hydroxysuccinimide gold nanoparticles, coated with polyethylene glycol (PEG) and conjugated to 64Cu-DOTA-BBN/BBN(7-14)/NMB and iron oxide nanoparticles coated with PEG and conjugated to 68Ga-DOTA-BBN/BBN(7-14)/NMB, respectively. Methods: The morphology and size distribution of gold/iron oxide nanoparticles were examined by TEM/SEM coupled with energy dispersion spectroscopy (EDS) techniques and, after functionalization, by UV-Vis spectroscopy and DLS. The gold/iron oxide NPs were fconjugated to PEG(4)-BBN(7-14), PEG(4)-BBN, and PEG(4)-NeuromedinB, previously radiolabelled with Cu-64 using DOTA as chelating agent. The radiolabelled nanoconjugates were incubated with neuroendocrine colorectal cancer cells HT-29 and HCT116, and prostate cancer cells DU-145, all over-expressing GRPRs. We investigated the specific binding of Bombesin (BBN), Bombesin-like peptide sequence BBN(7-14) and Neuromedin B (NMB) to GRP receptors in the presence of cold competitor antagonist ligands. In-vivo PET imaging was performed on high-resolution micro-PET-CT system, on tumor bearing nude mice (Nu/J) inoculated with HT-29, HCT116 and DU-145 tumors, respectively. Results: In vitro binding kinetics assessment showed an increased retention of over 30% of radioisotope inside tumor cells in the case of AuNP-PEG(4)-64Cu-DOTA-BBN(7-14), compared to 64Cu-DOTA-PEG(4)-BBN(7-14) alone. Similarly, IONP-PEG(4)-64Cu-DOTA-NMB was better uptaken and internalized, compared to 64Cu-DOTA-PEG(4)-NMB alone. These results are attributed to the increased concentration and multiple binding sites of BBN-like peptides to GRPRs allowed by their exposure on the surface of NPs. Subsequently, higher internalization rate is promoted, by receptor-mediated endocytosis. Biodistribution/imaging studies, and the results show high and stable tumor uptake of the radiolabelled nanoconjugates, fast blood-clearance and allowed for determination of key PKs parameters, path of accumulation and excretion rate. Conclusions: The combination of size-controlled distribution of nanoparticles, functionalization with high-specific targeting peptides and Cu-64 radioisotope labelling resulted in highly promising imaging/therapeutic scaffolds, based on gold/iron oxide NPs coated with PEG(4) and bearing specific targeting 64Cu-DOTA-BBN analogs. Their preliminary in vitro and in vivo evaluation shows good results regarding uptake, retention, stability and PKs parameters. Further investigations are to be performed to determine the detailed dosimetry and therapeutic efficacy to extend the potential use to targeted radionuclide therapy, by use of highly cytotoxic potency of Auger-electrons emitted by Cu-64, inside the tumour, and specifically affecting the tumour cell metabolism. Research Support: This work was supported by a grant of the Romanian Ministry of Research and Innovation, UEFISCDI project number 64PCCDI/2018.

Separation and identification of the DL-forms of short-chain peptides using a new chiral resolution labeling reagent.

There are several reports of D-amino acids being the causative molecules of serious diseases, resulting in the formation of, for example, prion protein and amyloid β. D-Amino acids in peptides and proteins are typically identified by sequencing each residue by Edman degradation or by hydrolysis with hydrochloric acid for amino acid analysis. However, these approaches can result in racemization of the L-form to the D-form by hydrolysis and long pre-treatment for hydrolysis. To address these problems, we aimed to identify the DL-forms of amino acids in peptides without hydrolysis. Here, we showed that the DL-forms in peptides which are difficult to separate on a chiral column can be precisely separated by labeling with 1-fluoro-2,4-dinitrophenyl-5-D-leucine-N,N-dimethylethylenediamine-amide (D-FDLDA). Additionally, the peptides could be quantitatively analyzed using the same labeling method as for amino acids. Furthermore, the detection sensitivity of a sample labeled with D-FDLDA was higher than that of the conventional reagents Nα-(5-fluoro-2,4-dinitrophenyl)-L-alaninamide (L-FDAA) and Nα-(5-fluoro-2,4-dinitrophenyl)-L-leucinamide (L-FDLA) used in Marfey's method. The proposed method for identifying DL-forms of amino acids in peptides is a powerful tool for use in organic chemistry, biochemistry, and medical science.

Effect of amino acids and taste components on the fermented fish sauce (Budu) from Thailand

Budu is one of the most popular fermented fish products in Thailand's southern area due to its distinctive flavor. It is being manufactured in large quantities for usage in cuisine as seasonings and sauces. The objective of this study was to determine the effect of amino acids on the distinctive taste components of Budu in southern Thailand. The amino acids in Budu were determined using GC-MS after fish was fermented for 6–12 months as recommended by the manufacturer. Lysine, glutamic acid, and aspartic acid are the three most abundant amino acids, with 1600, 1,540, and 1,260 mg/100g, respectively. Additionally, it was revealed that the umami taste was formed by a group of amino acids (glutamic acid and aspartic acid) followed by sweetness and bitterness. The sensory analysis discovered salty tastes, followed by umami, sour, sweet, and bitter. Four Budu samples generate a salty and umami flavor. Salt is mixed with cleaned fresh fish and fermented to enable native enzymes to auto-digest the protein and produce amino acid-rich products. Fish enzymatic fermentation produces short-chain peptides and amino acids that contribute to the umami flavor and taste. Additionally, the fermentation process creates a high glutamic acid concentration, as well as other amino acids and nucleotides that add to the umami flavor of the products. The study findings will be information that is particularly beneficial to consumers and manufacturers to promote Budu products in the country's region.

Analysis of membrane transportation of cell penetrating peptides using lipid bilayer system

Cell-penetrating peptides (CPPs) are short-chain peptides that can deliver biomolecules into living cells. There are two different membrane permeation pathways: endocytosis and direct penetration accompanied by pore formation, carpet, and inverted micelle formation model. The advantage of direct penetration is to avoid lysosomal degradation and cytotoxicity. However, little is known about the relationship between direct penetration and the physicochemical properties of CPPs. Here we investigate that the mechanism of membrane permeation according to the characteristics of CPPs by electrophysiological methods using a planar lipid bilayer.

Investigation of the quality parameters of hydrolysates obtained from fish by‐products using response surface methodology

Fish protein hydrolysates (FPH), which comprise a combination of small protein or peptide and free amino acids, may be suitable for use in a variety of applications. For this purpose, the hydrolysis process was carried out for the by-products of trout, whiting, and anchovy with alkaline protease, protamex, and flavourzyme, and the quality of the protein hydrolysate generated under optimized conditions was determined by proximate compositions, amino acid contents, heavy metal, and trace element levels and peptide molecular weight sizes. The time, temperature, and enzyme proportions were determined according to the hydrolysis degree (DH%) under optimum conditions identified by response surface methodology (RSM). The crude protein, lipid, and ash contents of trout, whiting, and anchovy by-products hydrolysates ranged from 77.03% to 88.54%, 3.28% to 6.12%, and 8.18% to 16.8% for dry matter, respectively. Considering the total amino acid contents, the highest number of amino acids was aspartic and glutamic acid in all fish and enzyme groups. In terms of essential amino acids, the highest concentrations of cystine, histidine, lysine, and methionine were found in anchovy by-product hydrolysates produced using the flavourzyme. Using FAO/WHO reference protein as a base, lysine was found to have the highest chemical score for trout by-products hydrolysates using protamex (85.14%), whiting by-products hydrolysates using alkaline protease (83.66%), and anchovies by-products hydrolysates using flavourzyme (88.45%). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that the electrophoresis pattern of the hydrolysates of trout, whiting, and anchovy by-products optimized with the RSM using alkaline protease, protamex, and flavourzyme enzymes showed variations depending on the enzyme type and fish by-products. Practical applications The enzymatic hydrolysis of proteins, which produces protein hydrolysates that are composed of free amino acids and short-chain peptides, has proven to be one of the most successful methods for recovering value-added proteins from fish by-products while maintaining their nutritional value. Because of the amino acid composition of these free amino acids and short-chain peptides of hydrolysate, they have several benefits as nutraceuticals or functional foods. As shown in this work, hydrolysates of fish by-products (trout, whiting, and anchovy) improved using the RSM applying alkaline protease, protamex, and flavourzyme enzymes demonstrated that it is an excellent source of important amino acids, particularly lysine and short-chain peptides. Consequently, recent research findings suggest that hydrolysates of trout, whiting, and anchovy by-products may be utilized as bioactive components in a variety of nutritional, pharmacological, cosmetic, and nutraceutical applications.

Effect of pentagastrin and gastrin-17 on the secretory function of the gastric glands

The regulation of the digestive glands of the stomach and pancreas in the body of animals and humans is provided by peptides, most of which are in various molecular forms. 10 molecular forms of peptides of the gastrin group and 5 peptides of the cholecystokinin (CCK) group have been identified, containing in their structure from 4 to 56 amino acids, the physiological role of which has been little studied. It has been proven that the liver removes up to 85% of short-chain peptides of the gastrin (pentagastrin) and cholecystokinin (CCK-8) groups.

Investigation of cerebrovascular activity of new GABA-derived short peptides

Based on the important role of endogenous substances in the cerebral blood flow regulation, the cerebrovascular activity of new synthesized short peptides of γ-aminobutyric acid (GABA) and pyroglutamate has been investigated, considering the development of new drugs for the correction of cerebral circulation. Taking into account the proven ability to increase cerebral blood flow of γ-aminobutyric acid and its endogenous metabolites, such as gamma butyrolactone, gamma hydroxybutyric acid, pyrrolidone, pyroglutamic acid, as well as synthetic analogues, such as picamilon, the influence of pyroglutamyl GABA, pyroglutamyl GABA ethyl ester, pyroglutamyl diGABA was observed on local brain blood flow in a state of impaired cerebral circulation. The model of cerebral chronic hypoperfusion generated by right common carotid artery occlusion was used on rats weighing 180-240 g, under anesthesia with chloral hydrate (400 mg/kg). The investigated peptides were administered at a dose of 20 mg/kg, intraperitoneally. Cerebral blood flow changes were detected by laser Doppler flowmetry. The conducted experiment revealed differences between the cerebrovascular activities of the studied short peptides. Thus, it was demonstrated that pyroglutamyl GABA exhibits а high ability to increase local cerebral blood flow, stimulating cerebral circulation by 65,2 %, compared with the value of hypoperfusion by right common carotid artery occlusion, after 40 minutes of injection. However, no essential changes in the studied indicator were recorded for pyroglutamyl GABA ethyl ester and pyroglutamyl diGABA. The obtained data indicate that the prolongation of the short peptide chain leads to a decrease in cerebrovascular activity and opens up new perspectives for the development of pyroglutamyl GABA dipeptide as a promising agent for the correction of cerebral circulation

Anti-Vascular Endothelial Growth Factor Drug Conbercept-Loaded Peptide Hydrogel Reduced Angiogenesis in the Neovascular Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) accounts for 8.7% of the global blindness and neovascular form of AMD (nAMD) occupies a large proportion of severe visual loss and legal blindness caused by AMD with a relatively low incidence rate. Choroidal neovascularization (CNV) is overwhelmingly responsible for the occurrence of nAMD as bleeding and fluid leakage followed by abnormal formation of blood vessels could directly lead to loss of central vision so that reduce the choroidal angiogenesis is an ideal treatment method of nAMD. VEGF is an important cytokine which promote the signaling pathway of angiogenesis and the abnormal expression of VEGF is verified in great many CNV cases. Several anti-VEGF drugs have been widely used in clinical treatments such as ranibizumab, bevacizumab and aflibercept. Conbercept, as an originally developed drug in China, has attracted great attention. For the purpose of better treatment efficacy, our group designed a short chain peptide (Sequence: DDIIIRH-NH₂, M.W.880.99) for controlled drug release to remedy the drawback of the short half-time period. The peptide could self-assembled into a stable 'hydrogel under pH 7.4 condition and the 3D structure was clearly observed in TEM study. Rheological study exhibited its great injectability so that the hydrogel was a material for intravitreal injection. Statistics exhibited that the hydrogel could release approximately 50% of total conbercept. The In vitro experiments showed that either dose-dependent or the time-dependent incubation with peptide would not decrease the cell viability of HREC, revealing that the peptide was biocompatible. The most important is that co-incubation with HREC obviously reduced the HREC proliferation and tube formation induced by VEGF, ensuring its potential for the treatment efficacy of nAMD.

Nutritional evaluation of whey protein hydrolysate: chemical composition, peptide profile, and osmolarity

The expediency of processing whey is confirmed by the value of its composition, amount of raw materials, and the possibility of obtaining a wide range of food products and ingredients based on it. The most appropriate technological method for reducing the antigenicity of whey proteins in the food industry is enzymatic hydrolysis. The work aims to study the chemical composition and properties of hydrolysis products of cheese whey UF concentrate with enzyme preparations Promod 439L and Flavorpro 766MDP to determine processing areas of the obtained hydrolysate. At the same time, 65% and 40% of peptide bonds in the antigenic epitopes of β-lactoglobulin and α-lactoalbumin, respectively, were broken without a significant increase in the osmolarity of the food system (291±2 mOsm/dm3 in the hydrolysate). Among the products of proteolysis, short-chain peptides predominate. The resulting product indicates reduced allergenicity and high content of essential amino acids. The resulting hydrolysate can be used in the technology of various dairy products to replace skimmed milk in the preparation of a normalized mixture, manufacture of products for preventive nutrition of people allergic to cow's milk proteins, and as the main ingredient in beverages for sports nutrition.

Analysis of short-chain bioactive peptides by unified chromatography-electrospray ionization mass spectrometry. Part II. Comparison to reversed-phase ultra-high performance liquid chromatography

In the first part of this study, a unified chromatography (UC) analysis method, which is similar to supercritical fluid chromatography (SFC) but with wide mobile phase gradients of pressurized CO2 and solvent, was developed to analyse short-chain peptides, with UV and mass spectrometry (MS) detection. In this second part, the method is compared to a reference reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) method, based on the analysis of 43 peptides, including 10 linear peptides and 33 cyclic ones.First, the orthogonality between the two methods was examined, based on the retention patterns. As the UC method was developed on a polar stationary phase (Ascentis Express OH5), the elution orders and selectivities were expected to be significantly different from RPLC on a non-polar stationary phase (ACQUITY CSH C18). Secondly, the success rate of the methods was examined, based on successful retention / elution of the peptides and the absence of observed co-elutions between the main peak and impurities. A successful analysis was obtained for 81% of the peptides in UC and 67% in RPLC. Thirdly, the performance of the methods for the intended application of impurity profiling of peptide drug candidates was assessed, based on the comparison of peak purities, the number of impurities detected and the thorough examination of impurity profiles. Excellent complementarity of the two methods for the specific task of impurity profiling, and for the separation of isomeric species was observed, with only one isomeric pair in this set remaining unresolved. The method sensitivity was however better with RPLC than UC. Finally, the operational costs in terms of solvent cost per analysis were the same between the two methods.

Impact of Intrinsic and Extrinsic Factors on the Pharmacokinetics of Peptides: When Is the Assessment of Certain Factors Warranted?

Peptides are short chains of 2 to 50 amino acids (molecular weight of less than 10 kDa) linked together by peptide bonds. As therapeutic agents, peptides are of interest because the body naturally produces many different peptides. Short-chain peptides have many advantages as compared with long-chain peptides (e.g., low toxicity). The first peptide corticotropin was approved in 1952 for multiple inflammatory diseases and West syndrome. Since then, more than 60 peptides have been approved by the FDA. Pharmacokinetics (PK) is widely used in modern-day drug development for designing a safe and efficacious dose to treat a wide variety of diseases. There are, however, several factors termed as “intrinsic” or “extrinsic” which can influence the PK of a drug, and as a result, one has to adjust the dose in a patient population. These intrinsic and extrinsic factors can be described as age, gender, disease states such as renal and hepatic impairment, drug–drug interaction, food, smoking, and alcohol consumption. It is well known that these intrinsic and extrinsic factors can have a substantial impact on the PK of small molecules, but for macromolecules, the impact of these factors is not well established. This review summarizes the impact of intrinsic and extrinsic factors on the PK of peptides.

Upper-Critical-Solution-Temperature Polymer Modified Gold Nanorods for Laser Controlled Drug Release and Enhanced Anti-Tumour Therapy.

Photothermal therapy (PTT) has become effective method for the treatment of malignant cancer. The development of PTT system with high anti-tumour effect is still the feasible research direction. Here, a new type of gold nanorods (AuNRs)-doxorubicin (DOX)/mPEG10K-peptide/P(AAm-co-AN) (APP-DOX) nano drug delivery system was proposed. Among them, AuNRs was used as high-efficiency photothermal agent. APP-DOX had a suitable size and can be targeted to accumulate in tumour tissues through circulation in the body. The abundant matrix metalloproteinase 2 (MMP-2) in the tumour environment intercepted and cut off the short peptide chain structure grafted on APP-DOX. At the same time, the removal of the PEG segment leaded to an increase in the hydrophobic properties of the system. Nanoparticles aggregated into large particles, causing them to stay and aggregate further at the tumour site. When irradiated by 808 nm near-infrared laser, APP-DOX achieved a gradual heating process. High temperature can effectively ablate tumours and enable UCST polymer to achieve phase transition, resulting in more anti-cancer drugs loaded in the polymer layer DOX was released, effectively killing cancer cells. Animal experiments had verified the possibility of the nano drug-carrying system and good tumour treatment effect. What’s more worth mentioning is that compared with free DOX, the nano drug delivery system had lower biological toxicity and not cause obvious harmful effects on normal organs and tissues.

Hybrid fusion protein as a dual protease inhibitor for the healing of chronic wounds.

Diseases bring about the need for interventions that pinpoint each specific aspect of the illness. Commonly, remission of a complex disease is accomplished by mixing treatments, medications, and therapeutics together in a fashion where they may negatively interact with each other or never arrive at the diseased site as a systemic heterogeneous mixture. Chronic wounds display intricacy as they are very localized and have their own environment where tissue deconstruction due to high levels of numerous proteases outweighs normal tissue reconstruction. This idea leads to the necessity of a protein that contains low diffusivity rates for localized treatment, strength against high concentrations of proteolytic species that lead to degradation of short chain peptides, while encompassing broad inhibitory effects against multiple proteases. Elastin-like peptides are an attractive, thermoresponsive, protein-based drug delivery partner as they contain low diffusivity and serve as a stable architecture for short chain peptide fusion. In this project, a novel elastin-like peptide-based protein has been created to target the inhibition of both human neutrophil elastase and matrix metalloprotease-2. As a biologic, this is unique as it is a protein with specific biological activities against multiple proteases, ultimately displaying the potential to mix and match differing biologically active peptides within one amino acid sequence.

In vitro digestion characteristics of cereal protein concentrates as assessed using a pepsin-pancreatin digestion model

An alkaline extraction method has been used in many studies to extract total protein from cereal samples. Wheat bran protein concentrate (WBPC), oat bran protein concentrate (OBPC), and barley protein concentrate (BPC) were prepared by alkaline extraction and isoelectric precipitation to study their functional and nutritional properties. The three protein concentrates were hydrolysed by an in vitro pepsin-pancreatin digestion model. Their digestibility (%) and degree of hydrolysis (DH%) were evaluated, and SDS-PAGE electrophoresis was used to illustrate the protein and peptides patterns. The change of the particle sizes and the release of the essential amino acids was followed during the digestion process. The in vitro digestibility of WBPC, OBPC and BPC was 87.4%, 96.1% and 76.9%, respectively. The DH% of protein concentrates were between 50 and 60%. The change of the particle size distribution values Dv(50) was assumed to be related to protein aggregations during the digestion. The protein fractions were identified and the degradation during the digestion and were analysed by SDS-PAGE; the gels of WBPC and OBPC digestion showed virtually complete degradation whereas the intensive bands of undigested protein were presented for BPC. The generation of the free amino acids and short chain peptides were significantly higher at the end of the intestinal digestion compared to the stages of before and after gastric digestion. Higher content of the deficient amino acids such as lysine and threonine were found comparing to the level of deficient amino acids in cereal grains but does not meet the daily recommended intake.

Triglycine (GGG) Adopts a Polyproline II (pPII) Conformation in Its Hydrated Crystal Form: Revealing the Role of Water in Peptide Crystallization.

Polyproline II (pPII) is a left-handed 31-helix conformation, which has been observed to be the most abundant secondary structure in unfolded peptides and proteins compared to α-helix and β-sheet. Although pPII has been reported as the most stable conformation for several unfolded short chain peptides in aqueous solution, it is rarely observed in their solid state. Here, we show for the first time a glycine homopeptide (gly-gly-gly) adopting the pPII conformation in its crystalline dihydrate structure. The single crystal X-ray structure with molecular dynamic simulation suggests that a network of water and the charged carboxylate group is critical in stabilizing the pPII conformation in solid state, offering an insight into the structures of unfolded regions of proteins and the role of water in peptide crystallization.

Benefit of a Short Chain Peptide as a Targeting Ligand of Nanocarriers for a Brain-Driven Purpose.

Treatment of glioma remains a critical challenge worldwide, since the therapeutic effect is greatly hindered by poor transportation across the blood brain barrier (BBB) and low penetration into tumor cells. In this study, a peptide-conjugated nano-delivery system was explored for the purpose of glioma therapy. A peptide-decorated copolymer was used to prepare nanoparticles (NPs) by a solvent evaporation method. The particle size was in the range of 160.9 ± 3.3–173.5 ± 3.6 nm with monodistribution, and the zeta potentials ranged from −18.6 ± 1.2 to +7.9 ± 0.6 mV showing an increasing trend with R9-peptide. An in vitro cocultured BBB model illustrated the internalization of peptide-conjugated NPs in bEnd.3 cells followed by uptake by U87-MG cells indicating both BBB-crossing and glioma-penetrating abilities. IVIS (In Vivo Imaging System) images revealed that T7-conjugated NPs specifically accumulated in the brain more than peptide-free NPs and had less biodistribution in nontarget tissues than T7/R9 dual-peptide conjugated NPs. The benefit of T7-peptide as a targeting ligand for NPs across the BBB with accumulation in the brain was elucidated.

Evaluation of Short-Chain Antimicrobial Peptides With Combined Antimicrobial and Anti-inflammatory Bioactivities for the Treatment of Zoonotic Skin Pathogens From Canines.

The incidence of zoonotic Staphylococcus pseudintermedius and Microsporum canis infections is rapidly growing worldwide in the context of an increasing frequency of close contact between animals and humans, presenting challenges in both human and veterinary medicine. Moreover, the development of microbial resistance and emergence of recalcitrant biofilms, accompanied by the insufficiency of new antimicrobial agents, have become major obstacles in treating superficial skin infections caused by various microbes including S. pseudintermedius and M. canis. Over recent years, the prospects of antimicrobial peptides as emerging antimicrobials to combat microbial infections have been demonstrated. In our study, two novel short-chain peptides, namely, allomyrinasin and andricin B, produced by Allomyrina dichotoma and Andrias davidianus, were revealed to exhibit potent antimicrobial efficacy against clinical isolates of S. pseudintermedius and M. canis with remarkable and rapid fungicidal and bactericidal effects, while allomyrinasin exhibited inhibition of biofilm formation and eradication of mature biofilm. These peptides displayed synergistic activity when combined with amoxicillin and terbinafine against S. pseudintermedius and M. canis. Cytoplasmic leakage via cytomembrane permeabilization serves as a mechanism of action. Extremely low hemolytic activity and serum stability in vitro, as well as superior anti-infective efficacy in reducing bacterial counts and relieving the inflammatory response in vivo, were detected. The potent antibacterial, antifungal, and anti-inflammatory activities of allomyrinasin and andricin B might indicate promising anti-infective alternatives for the treatment of S. pseudintermedius and M. canis infections in the context of human and veterinary medicine.

Synthesis, Characterization and Evaluation of Peptide Nanostructures for Biomedical Applications.

There is a challenging need for the development of new alternative nanostructures that can allow the coupling and/or encapsulation of therapeutic/diagnostic molecules while reducing their toxicity and improving their circulation and in-vivo targeting. Among the new materials using natural building blocks, peptides have attracted significant interest because of their simple structure, relative chemical and physical stability, diversity of sequences and forms, their easy functionalization with (bio)molecules and the possibility of synthesizing them in large quantities. A number of them have the ability to self-assemble into nanotubes, -spheres, -vesicles or -rods under mild conditions, which opens up new applications in biology and nanomedicine due to their intrinsic biocompatibility and biodegradability as well as their surface chemical reactivity via amino- and carboxyl groups. In order to obtain nanostructures suitable for biomedical applications, the structure, size, shape and surface chemistry of these nanoplatforms must be optimized. These properties depend directly on the nature and sequence of the amino acids that constitute them. It is therefore essential to control the order in which the amino acids are introduced during the synthesis of short peptide chains and to evaluate their in-vitro and in-vivo physico-chemical properties before testing them for biomedical applications. This review therefore focuses on the synthesis, functionalization and characterization of peptide sequences that can self-assemble to form nanostructures. The synthesis in batch or with new continuous flow and microflow techniques will be described and compared in terms of amino acids sequence, purification processes, functionalization or encapsulation of targeting ligands, imaging probes as well as therapeutic molecules. Their chemical and biological characterization will be presented to evaluate their purity, toxicity, biocompatibility and biodistribution, and some therapeutic properties in vitro and in vivo. Finally, their main applications in the biomedical field will be presented so as to highlight their importance and advantages over classical nanostructures.