Protein Polypeptide Research Articles

Tianxiangdan (TXD) alleviates myocardial ischemia reperfusion-induced ferroptosis through the activation of estrogen receptor alpha (ERα).

Tianxiangdan (TXD), a traditional Chinese herbal remedy, demonstrates efficacy in mitigating myocardial ischemia-reperfusion (I/R)-induced damage. This study employed network pharmacology to evaluate the therapeutic targets and mechanisms of TXD in treating I/R. High-performance liquid chromatography-mass spectrometry (HPLC-MS) identified 86 compounds in TXD. Network pharmacological analysis predicted potential target genes and their modes of action. Cardiac function, ischaemic ST changes, lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) activity, myocardial fiber, and infarct size were assessed using in vivo and in vitro I/R injury models. Estrogen receptor alpha (ERα) protein expression and estradiol (E2) levels were measured to confirm TXD's impact on estrogen levels and ERα expression. To examine if TXD reduces I/R injury through ERα, an AZD group (300 nmol·L-1 AZD9496 and 15% TXD serum) was compared to a TXD group (15% TXD serum). The study hypothesized that TXD upregulates the ERα-mediated iron metamorphosis pathway. I/R injury-induced ferroptosis was identified using a Fer-1 group (1.0 μmol·L-1 Fer-1 and 15% TXD serum) to elucidate the potential association between ferroptosis and ERα proteins. A DCFH-DA probe detected reactive oxygen species (ROS) and Fe2+, while Western blotting assessed target protein expression. Both in vitro and in vivo experiments demonstrated that TXD attenuated I/R injury by reducing elevated ST-segment levels, improving cardiac injury biomarkers (LDH, MDA, and SOD), alleviating pathological features, and preventing I/R-induced loss of cell viability in vitro. The effects and mechanisms of TXD on I/R injury-associated ferroptosis were investigated using I/R-induced H9c2 cells. The TXD group showed significantly decreased ROS and Fe2+ levels, while the AZ group (treated with AZD9496) exhibited increased levels. The TXD group demonstrated enhanced expression of ERα and glutathione peroxidase 4 (GPX4), with reduced levels of P53 protein and ferritin-heavy polypeptide 1 (FTH1). The AZ group exhibited contrasting effects on these expression levels. The literature indicated a novel connection between ERα and ferroptosis. TXD activates the ERα signaling pathway, promoting protection against I/R-induced myocardial cell ferroptosis. This study provides evidence supporting TXD use for myocardial ischemia treatment, particularly in older female patients who may benefit from its therapeutic outcomes.

Serologic and molecular identification of the variation on ABO*B.01 gene in ABO glycosyltransferases associated with Bw phenotype: a case report.

AB antigen is formed by glycosyltransferase enzyme, which catalyzes the corresponding substrates to be connected to the galactose of the precursor substance H antigen. To study the effect of the α-1,3-D galactosyltransferase (GTB) gene mutation on B antigen expression, we explored its molecular mechanism by combining molecular biological methods with bioinformatics. The ABO blood type of the patients was identified using conventional serologic methods, and the polymerase chain reaction (PCR) products of exons 1-7 of the ABO gene were directly sequenced using gene-specific primers and direct sequencing. Proteins in the secretory supernatant of transfected cells were collected in vitro, and GTB content was quantitatively analyzed using western blotting. Bioinformatics software was used to simulate the 3-dimensional structure of the mutant protein. In this case, the patient's serologic test results revealed subtype B. Gene sequencing results confirmed a mutation at base 278 of exon 6. The mutation (c.278C>T) changed the 93rd amino acid of the protein polypeptide chain from proline to leucine (p.P93L). The variant p.P93L did not affect the expression and secretion of GTB, but affected enzyme activity and stability, ultimately manifesting as weakened expression of the B antigen and reduced affinity.

Supplementation of Parachlorella sp. in feed promote the gut microbiome colonization and fecal IgA response of broiler in both early and late period

This study evaluated the effects of Parachlorella sp. KSN1 (PA) supplementation on the gut microbiota and intestinal immunity of broilers of different ages. A total of 180 Ross 308 broiler chicks were weighed and divided into early (1 to 10 days post hatch) and late (11 to 28 days post hatch) periods, with six replicates of 10 chicks per cage assigned to two dietary groups. The experimental diets included a corn-soybean meal-based control diet and a treatment diet supplemented with 0.5% PA, replacing corn or corn starch, and fed ad libitum for the assigned experimental period. On days 10 and 28, two broilers from each of the six replicate cages, with 7 broilers per cage in each group, were selected and euthanized, and cecal feces and intestinal tissue samples were collected. PA supplementation did not significantly affect broilers growth performance during both the early and the late periods. However, PA supplementation altered the cecal microbiome, with Clostridiaceae and Clostridium exhibiting prominent and consistent changes. In terms of intestinal immunity, PA supplementation significantly increased the number of CD3+ and CD4+ T cells when administered only during the early period. Cecal IgA levels were significantly increased by PA supplementation during both the early and late periods. A significant positive correlation was observed between IgA, Clostridiaceae and Clostridium during the early and late periods. Gene expression analysis identified 40 upregulated genes, including polymeric immunoglobulin receptor (pIgR), and 142 downregulated genes, including marginal zone B and B1 cell specific protein and immunoglobulin lambda-like polypeptide 1 that were associated with the IgA response in PA-treated broilers during the early period. This study demonstrated that PA supplementation promotes gut microbial colonization and intestinal immunity development during the early age of broilers. These findings suggest that the early growth period of broilers is the optimal time for dietary immunomodulation to promote gut health in broilers.

A lightweight visualization tool for protein unfolding by collision detection and elimination

The experiments involving protein denaturation and refolding serve as the foundation for predicting the three-dimensional spatial structures of proteins based on their amino acid sequences. Despite significant progress in protein structure engineering, exemplified by AlphaFold2 and OmegaFold, there remains a gap in understanding the folding pathways of polypeptide chains leading to their final structures. We developed a lightweight tool for protein unfolding visualization called PUV whose graphics design is mainly implemented by OpenGL. PUV leverages principles from molecular biology and physics, and achieves rapid visual dynamics simulation of protein polypeptide chain unfolding through mechanical force and atom-level collision detection and elimination. After a series of experimental validations, we believe that this method can provide essential support for investigating protein folding mechanisms and pathways.

Electron transport through two interacting channels in Azurin-based solid-state junctions

The fundamental question of "what is the transport path of electrons through proteins?" initially introduced while studying long-range electron transfer between localized redox centers in proteins in vivo is also highly relevant to the transport properties of solid-state, dry metal-protein-metal junctions. Here, we report conductance measurements of such junctions, Au-(Azurin monolayer ensemble)-Bismuth (Bi) ones, with well-defined nanopore geometry and ~103 proteins/pore. Our results can be understood as follows. (1) Transport is via two interacting conducting channels, characterized by different spatial and time scales. The slow and spatially localized channel is associated with the Cu center of Azurin and the fast delocalized one with the protein's polypeptide matrix. Transport via the slow channel is by a sequential (noncoherent) process and in the second one by direct, off-resonant tunneling. (2) The two channels are capacitively coupled. Thus, with a change in charge occupation of the weakly coupled (metal center) channel, the broad energy level manifold, responsible for off-resonance tunneling, shifts, relative to the electrodes' Fermi levels. In this process, the off-resonance (fast) channel dominates transport, and the slow (redox) channel, while contributing only negligibly directly, significantly affects transport by intramolecular gating.

Applications of Differential Geometry Linking Topological Bifurcations to Chaotic Flow Fields

At every point p on a smooth n-manifold M there exist n+1 skew-symmetric tensor spaces spanning differential r-forms ω with r=0,1,⋯,n. Because d∘d is always zero where d is the exterior differential, it follows that every exact r-form (i.e., ω=dλ where λ is an r−1-form) is closed (i.e., dω=0) but not every closed r-form is exact. This implies the existence of a third type of differential r-form that is closed but not exact. Such forms are called harmonic forms. Every smooth n-manifold has an underlying topological structure. Many different possible topological structures exist. What distinguishes one topological structure from another is the number of holes of various dimensions it possesses. De Rham’s theory of differential forms relates the presence of r-dimensional holes in the underlying topology of a smooth n-manifold M to the presence of harmonic r-form fields on the smooth manifold. A large amount of theory is required to understand de Rham’s theorem. In this paper we summarize the differential geometry that links holes in the underlying topology of a smooth manifold with harmonic fields on the manifold. We explore the application of de Rham’s theory to (i) visual, (ii) mechanical, (iii) electrical and (iv) fluid flow systems. In particular, we consider harmonic flow fields in the intracellular aqueous solution of biological cells and we propose, on mathematical grounds, a possible role of harmonic flow fields in the folding of protein polypeptide chains.

Screening Carbon Nano Materials for Preventing Amyloid Protein Aggregation by Adopting a Facile Method.

The soluble-to-toxic transformation of intrinsically disordered amyloidogenic proteins such as amyloid beta (Aβ), α-synuclein, mutant Huntingtin Protein (mHTT) and islet amyloid polypeptide (IAPP) among others are associated with disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and Type 2 Diabetes (T2D), respectively. The dissolution of mature fibrils and toxic amyloidogenic intermediates, including oligomers, continues to be the pinnacle in the treatment of neurodegenerative disorders. Yet, methods to effectively and quantitatively report on the interconversion between amyloid monomers, oligomers and mature fibrils fall short. Here we describe a simplified method that implements the use of gel electrophoresis to address the transformation between soluble monomeric amyloid proteins and mature amyloid fibrils. The technique implements an optimized but well-known, simple, inexpensive, and quantitative assessment previously used to assess the oligomerization of amyloid monomers and subsequent amyloid fibrils. This method facilitates the screening of small molecules that disintegrate oligomers and fibrils into monomers, dimers, and trimers and/or retain amyloid proteins in their monomeric forms. Most importantly, our optimized method diminishes existing barriers associated with existing (alternative) techniques to evaluate fibril formation and intervention.

Study on Nutrient Carrier of Mulch Based on Hydrogel @SiO2.

Soil conservation is one of the best methods to improve soil fertility and enhance crop growth efficiency. Replacing plastic mulch with biomass is an environmentally friendly strategy. Innovative encapsulated soil granules (ESGs) were developed using PVA/PC film as the wall material and rural soil as the core. The PVA/PC was synthesized using 60% protein polypeptide (PC) from leather waste scrap and 35% poly (vinyl alcohol) (PVA), which was optimized for water absorption expansion and water retention performance. The ESG-10 granulated with 10% PVA/PC exhibited good water absorption, moisture retention, and resistance to water solubility. As an auxiliary material for soil improvement, the amount of ESGs mixed with the topsoil at ratios of 0 g/m2, 200 g/m2, and 400 g/m2 was proportional to the soil insulation and moisture retention. In rapeseed cultivation, the experimental results indicated that the soil mulched with ESG-10 can maintain seedling vitality for a long time under low water content conditions.

Thermally Triggered Triazolinedione-Tyrosine Bioconjugation with Improved Chemo- and Site-Selectivity.

A bioconjugation strategy is reported that allows the derivatization of tyrosine side chains through triazolinedione-based "Y-clicking". Blocked triazolinedione reagents were developed that, in contrast to classical triazolinedione reagents, can be purified before use, can be stored for a long time, and allow functionalization with a wider range of cargoes and labels. These reagents are bench-stable at room temperature but steadily release highly reactive triazolinediones upon heating to 40 °C in buffered media at physiological pH, showing a sharp temperature response over the 0 to 40 °C range. This conceptually interesting strategy, which is complementary to existing photo- or electrochemical bioorthogonal bond-forming methods, not only avoids the classical synthesis and handling difficulties of these highly reactive click-like reagents but also markedly improves the selectivity profile of the tyrosine conjugation reaction itself. It avoids oxidative damage and "off-target" tryptophan labeling, and it even improves site-selectivity in discriminating between different tyrosine side chains on the same protein or different polypeptide chains. In this research article, we describe the stepwise development of these reagents, from their short and modular synthesis to small-molecule model bioconjugation studies and proof-of-principle bioorthogonal chemistry on peptides and proteins.

Deciphering the interaction mechanism between soy protein isolate and fat-soluble anthocyanin on experiments and molecular simulations

In this work, the acylated anthocyanin (Ca-An) was prepared by enzymatic modification of black rice anthocyanin with caffeic acid, and the binding mechanism of Ca-An to soybean protein isolate (SPI) was investigated by experiments and computer simulation to expand the potential application of anthocyanin in food industry. Multi-spectroscopic studies revealed that the stable binding of Ca-An to SPI induced the folding of protein polypeptide chain, which transformed the secondary structure of SPI trended to be flexible. The microenvironment of protein was transformed from hydrophobic to hydrophilic, while tyrosine played dominant role in quenching process. The binding sites and forces of the complexes were determined by computer simulation for further explored. The protein conformation of the 7S and 11S binding regions to Ca-An changed, and the amino acid microenvironment shifted to hydrophilic after binding. The results showed that more non-polar amino acids existed in the binding sites, while in binding process van der Waals forces and hydrogen bonding played a major role hydrophobicity played a minor role. Based on MM-PBSA analysis, the binding constants of 7S-Ca-An and 11S-Ca-An were 0.518 × 106 mol−1 and 5.437 × 10−3 mol−1, respectively. This information provides theoretical guidance for further studying the interaction between modified anthocyanins and biomacromolecules.

The molecular dynamics simulation of peptide-based structure adsorption inside nanochannel with surface roughness

Peptides result from partial hydrolysis of protein polypeptide chains. These atomic structures are the main section of various protein compounds. So, the adsorption process of these structures can be used in various medical applications. The small peptide structure is absorbed using a platinum nanochannel with cubic roughness in an aqueous environment in the present computational examination. Technically, the simulation of the nanochannel- peptide system is done using the Molecular Dynamics (MD) method. The different atoms' interactions in our systems are defined by DREIDING/Universal Force-Field (UFF), TIP3P, and Embedded Atom Model (EAM). Temperature, total energy (TE), Radial Distribution Function (RDF), profiles of density/velocity/temperature, absorption ratio, interaction energy, and volume were presented for t = 30 ns in order to provide a physical description of the peptide adsorption process. Our simulation results show the atomic stability of P-nanochannel system in the attendance of H2O molecules. Moreover, peptide absorption ratio inside the MD box reached a 78 % value. This result shows the appropriate behavior of a metallic nanochannel with rectangular roughness to adsorption of various protein-based structures, such as Ps for medical aims.

Identification of genes associated with the silk gland size using multi-omics in silkworm (Bombyx mori).

Silk gland size in silkworms (Bombyx mori) affects silk output. However, the molecular mechanisms by which genes regulate silk gland size remain unclear. In this study, silk glands from three pure silkworm strains (A798, A306 and XH) with different silk gland weight phenotypes were compared using transcriptomics and proteomics to identify differentially expressed genes (DEGs) and proteins (DEPs). When comparing A798 to A306 and A798 to XH, 830 and 469 DEGs were up-regulated, respectively. These genes were related to the gene ontology terms, metabolic process, transport activity and biosynthesis process. In addition, 372 and 302 up-regulated differentially expressed proteins were detected in A798 to A306 and A798 to XH, respectively, related to the gene ontology terms, ribosome and protein export, ribosome and polypeptide biosynthesis processes. Moreover, combined transcriptomics, proteomics and weighted correlation network analyses showed that five genes (BGIBMGA002524, BGIBMGA002629, BGIBMGA005659, BGIBMGA005711 and BGIBMGA010889) were significantly associated with the silk gland weight. Reverse Transcription-quantitative real-time Polymerase Chain Reaction (RT-qPCR)and Enzyme linked immunosorbent assay (ELISA) were used to verify the mRNA and protein expression of five genes in the silk glands and tissues of 18 silkworm strains. The results showed that four genes have higher expression levels in heavier silk glands. These genes are associated with glycogen metabolism, fatty acid synthesis and branched chain amino acid metabolism, thus potentially promoting growth and silk protein synthesis. These findings provide valuable insights into the molecular mechanisms underlying the relationship between silk gland weight and silk yield in silkworms.

In vitro antioxidant activity evaluation of pine nut peptides (Pinus koraiensis) fermented by Bacillus subtilis LS-45

In this study, we utilized the remarkable capabilities of Bacillus subtilis ls-45 during the fermentation process to generate pine nut peptide. Through gene sequencing, we confirmed the proficiency of Bacillus subtilis ls-45 in producing protease, thereby serving as a valuable enzymatic source for protein hydrolysis. Our investigation focused on examining the variations in amino acid types and quantities between enzymatic pine nut protein peptide (EPP) and fermented pine nut protein polypeptide (FPP). Furthermore, we conducted a comprehensive assessment of the in vitro antioxidant activities of EPP and FPP, encompassing measurements of their Hydroxyl radical scavenging rate, Total reducing capacity, Superoxide anion scavenging rate, and ABTS+ radical scavenging rate. Notably, FPP exhibited superior antioxidant capacity compared to EPP. By employing semi-inhibitory mass concentration (IC50) analysis, we determined that FPP displayed enhanced efficacy in neutralizing hazardous free radicals when compared to EPP.

Influence of Fermentation by Lactobacillus helveticus on the Immunoreactivity of Atlantic Cod Allergens.

Fermentation techniques may induce alterations in fish allergen immunoreactivity. In this study, the influence of fermentation with three different strains of Lactobacillus helveticus (Lh187926, Lh191404, and Lh187926) on the immunoreactivity of Atlantic cod allergens was investigated via several methods. Gradually reduced protein composition and band intensity due to the fermentation by strain Lh191404 were found in SDS-PAGE analysis, and decreased immunoreactivity of fish allergens was confirmed by Western blotting and ELISA analysis due to the fermentation of strain Lh191404. Additionally, results from nLC-MS/MS and immunoinformatics tools analysis demonstrated that the protein polypeptide and allergen composition of Atlantic cod showed evident alterations after fermentation, with the epitopes of the main fish allergens being heavily exposed and destroyed. These results indicated that the fermentation of L. helveticus Lh191404 could destroy the structure and linear epitopes of the allergens from Atlantic cod and may have considerable potential in mitigating the allergenicity of fish.

Influence of laser radiation of a surgical laser on the structure of bovine serum albumin molecules in vitro

The influence of laser radiation of a surgical laser on the physicochemical properties of bovine serum albumin molecules was studied. After exposure to laser radiation, the optical density of protein solutions increases, the fluorescence intensity decreases, a significant decrease of the intensity of the a-helix band on the Raman spectrum is observed and the refractive index of protein solution did not significantly change. However, the viscosity increased, and the pseudoplasticity of aqueous solutions of albumin decreased. There was no massive damage to the protein polypeptide chain, on the contrary, intensive aggregation was observed. Thus, in a bovine serum albumin solution subjected to contact action of laser radiation, the processes of partial denaturation and aggregation prevail, aromatic amino acid residues of the protein are damaged to a lesser extent, and fragmentation of albumin molecules is not observed.

A novel multi-component protein vaccine ECP001 containing a protein polypeptide antigen nPstS1 riching in T-cell epitopes showed good immunogenicity and protection in mice.

Tuberculosis (TB) is an infectious disease that seriously affects human health. Until now, the only anti-TB vaccine approved for use is the live attenuated Mycobacterium bovis (M. bovis) vaccine - BCG vaccine, but its protective efficacy is relatively low and does not provide satisfactory protection against TB in adults. Therefore, there is an urgent need for more effective vaccines to reduce the global TB epidemic. In this study, ESAT-6, CFP-10, two antigens full-length and the T-cell epitope polypeptide antigen of PstS1, named nPstS1, were selected to form one multi-component protein antigens, named ECP001, which include two types, one is a mixed protein antigen named ECP001m, the other is a fusion expression protein antigen named ECP001f, as candidates for protein subunit vaccines. were prepared by constructing one novel subunit vaccine by mixing or fusing the three proteins and combining them with aluminum hydroxide adjuvant, and the immunogenicity and protective properties of the vaccine was evaluated in mice. The results showed that ECP001 stimulated mice to produce high titre levels of IgG, IgG1 and IgG2a antibodies; meanwhile, high levels of IFN-γ and a broad range of specific cytokines were secreted by mouse splenocytes; in addition, ECP001 inhibited the proliferation of Mycobacterium tuberculosis in vitro with a capacity comparable to that of BCG. It can be concluded that ECP001 is a novel effective multicomponent subunit vaccine candidate with potential as BCG Initial Immunisation-ECP001 Booster Immunisation or therapeutic vaccine for M. tuberculosis infection.

Conformational changes and functional properties of soy lipophilic protein‐epicatechin complexes formed by non‐covalent interaction

SummarySoy lipoprotein (SLP) is the main component of soy protein isolate in addition to β‐conglycinin (7 S) and glycinin (11 S), The contents of 7 S, 11 S and SLP were 23%, 46% and 31%, respectively. It has the effect of reducing blood cholesterol and triglyceride and can be used as a good carrier for transporting conjugated linoleic acid. This study investigated the effect of the interaction between soy lipophilic protein (SLP) and epicatechin (EC) on protein structure, their binding mode, physicochemical and antioxidant activities. Different concentrations of epicatechin (0, 0.1, 0.2, 0.3, 0.4 and 0.5 mg mL−1) were used to interact with soybean lipophilic protein. Identification of the binding mode of SLP and EC was achieved by Fluorescence and Fourier transform infrared (FTIR) spectroscopy. It was revealed that epicatechin bound to SLP mainly through hydrophobic interaction. The addition of EC changed the secondary structure of SLP, decreased α‐helix and random coil contents and increased β‐strand contents. Fluorescence spectrum analysis results showed that after the combination of SLP with EC, the tertiary structure of the protein became loose and the surface hydrophobicity decreased due to unfolding of the protein polypeptide chain. The emulsifying and antioxidant activities of SLP were improved after complexation with EC. This study provides clarifications on the mechanism of the formation of SLP‐EC complex and provides a new avenue in developing new food carriers using plant proteins and polyphenols.

Sustainable recycling of café waste as natural bio resource and its value adding applications in green and effective dyeing/bio finishing of textile

Cafe waste, such as spent coffee grounds and tea leaves, possesses abundant natural colorants and bio active chemicals, which can be extracted using simple and eco-friendly process. This work investigated cafe waste recycling process by optimizing natural colorant extracting condition, and then applied the extracted natural bio dye to textile dyeing and functional finishing. A simple and green process is carefully designed in an attempt to reduce cost and hazards to the environment, and a comparison is made between the two agriculture/food wastes. Results showed that 50% ethanol + sodium bicarbonate solvent system with a weak alkaline condition of pH 8, can be an effective solvent for extracting natural colorants and bio active chemicals from both spent coffee grounds and tea leaves. Silk and wool fabrics dyed with the extracts exhibited natural brownish color with satisfactory color fastness, owing to effective adsorption of natural dye onto the fibers through strong chemical interactions between protein polypeptide chains and dye molecules. In addition to the natural color, antioxidant and antibacterial properties are that textile can achieve from cafe waste through dyeing. It is seen in this work an extraordinary high level (>90%) of antibacterial activities (against E.coli, S.aureus and C. albicans) achieved by dyed fabrics in all cases. The recycling loop can be closed by processing leftovers directly and safely go back to nature as mulch or mixed with soil as fertilizer, free from prior composting.

Исследование амилоидоигенного потенциала неспецифических поринов Yersinia pseudotuberculosis

The paper considers the process of formation and properties of amyloid-like aggregates of outer membrane non-specific porins (OmpC and OmpF) of the gram-negative bacterium Yersinia pseudotuberculos in an acidic medium (pH 4.5) at elevated temperature. The dynamics of the formation of amyloid-like aggregates of porins was monitored after two and four weeks of incubation (at 42 °C) and after 3-5 hours (at 90 °C) by staining the samples with amyloid-specific dye thioflavin T, analyzing the spectra of circular dichroism in the far UV region, IR -spectroscopy and confocal microscopy. It was found that in the case of porin OmpC, incubation under mild conditions (42°C) leads to a reversible accumulation of α-helical regions in the protein polypeptide chain. No significant changes are observed in the spatial structure of OmpF porin under these conditions, however, under harsh conditions (95 ºC) amyloid-like aggregates are formed, which are characterized by an increased content of the β-sheet structure. Using IR spectroscopy, it was shown that the conformational rearrangement in the molecule of OmpF porin is associated with a change in the quantity and quality of elements of the β-structure. According to confocal microscopy, the aggregates of the studied non-specific porins can be considered as intermediate products of the amyloidogenic pathway - oligomers. According to the literature data, these oligomers, which precede the formation of mature fibrils, have membranolytic and cytotoxic properties. For heated samples of the studied porins during reconstitution into bilayer lipid membranes, neither pore-forming nor membranolytic activity was detected. With respect to Neuro-2a CCL-131™ mouse neuroblastoma cells, the aggregates of OmpF and OmpC porins obtained after incubation had a higher toxicity compared to the initial protein samples.

Screening of immunopeptides from Zhiciweipi (Corium Erinacei Praeparaum) and their immunity to RAW264.7 macrophages

Zhiciweipi (Corium Erinacei Praeparaum) is one of the traditional Chinese animal medicines used to treat hematochezia and hemorrhoids. At present, there is a lack of the workflow for ingredient identification of Zhiciweipi (Corium Erinacei Praeparaum) and the studies regarding immunocompetent ingredient screening and evaluation. This study aims to screen immunopeptides in Zhiciweipi (Corium Erinacei Praeparaum) and investigate their immunity to RAW264.7 macrophages. In this study, the workflow for protein polypeptide identification and analysis of Zhiciweipi (Corium Erinacei Praeparaum) was established based on LC-MS/MS. According to Gene ontology_Biological process (GO_BP) functional and signal pathway enrichment analysis results, the identified proteins are related with vascular development, wound healing, IL2 STAT5 signal, and so on. A total of 20 immune regulatory genes were identified from the Venn diagram of protein and immune regulatory genes in Zhiciweipi (Corium Erinacei Praeparaum). The PPI network analysis demonstrated that ALB protein ranks the top in term of significance. According to analysis on physical properties and structural and safety prediction of 61 polypeptide fragments related with serum albumin in Zhiciweipi (Corium Erinacei Praeparaum) which are corresponding to ALB protein, RHPYFYAPELL and RHPYFYAPELLYF (RHP-LYF) are the most optimal. The molecular docking showed that RHPYFYAPELL and RHP-LYF can make effective bonding with IL-2 and STAT5. The molecular dynamic experiment reflected that RHP-LYF has the strongest affinity with ALB. In the present study, CCK8 method was applied to test RHP-LYF treatment of RAW264.7 cells in the mice macrophage system at different concentrations. Results showed that such treatment may not inhibit cell growth when the RHP-LYF concentration is lower than 200 ng/mL. The polypeptide fluorescence marking experiment proved that polypeptides can enter into cells and can be detected in the whole cell. Effects of RHP-LYF on IL-2, TNFα, IFNγ and IL10 levels in RAW264.7 cells and mice serum were detected by ELISA kit. Results showed that polypeptide not only can inhibit secretion of inflammatory factors in vivo and in vitro, but also promote secretion of anti-inflammatory factors, and further test effects of RAW264.7 cells on expressions of p-STAT5 and STAT5 through Western Blot. Results showed that polypeptide treatment may inhibit level of p-STAT5 and has dosage-dependent effect. Polypeptides from Zhiciweipi (Corium Erinacei Praeparaum) are safe and have immunization to RAW264.7 macrophage. All of these results can provide a meaningful method to drug quality assessment, immune bioactive peptide screening and evaluation of Zhiciweipi (Corium Erinacei Praeparaum) and other animals rich of peptides.