Fatty acid modification of casein bioactive peptides nano-assemblies, synthesis, characterization and anticarcinogenic effect.

In this study, the nano-assemblies of bovine casein hydrolyzed peptides (HP) modified by fatty acids with various alkyl chain lengths (C8, C10, C12 and C14) were synthesized. The physicochemical properties of HP-C8-HP-C14 nano-assemblies were characterized using spectra, laser particle size analyzer, contact angle meter, scanning electron microscope (SEM) and cryo-transmission electron microscope (Cryo-TEM). HP-C8 and HP-C10 self-assembled into a hollow cube cage with an average size of ~500 nm, and the assembly of HP-C12 showed a flower-shaped morphology with more dispersed behavior, and droplet size was observed as ~20 nm. The in vitro cytotoxicity against human breast cancer cells MCF-7 was tested using CCK-8 assay and flow cytometry analysis. HP-C12 showed the highest cytotoxicity for MCF-7 cells with an inhibition rate of 66.03 % ± 0.35 % with an IC50 value of 7.4 µM among HP-Cn. HP-C8, HP-C10 and HP-C12 significantly affected on the migration, invasion and apoptosis of MCF-7 cells. The apoptosis mechanism may depend on the upregulation of anti-apoptotic protein Bcl-2 as well as pro-apoptotic proteins Bax and caspase-8. The dead MCF-7 cells were analyzed with UHPLC-MS/MS using untargeted metabolomics, revealing key metabolic pathways.

Developments in small-angle X-ray scattering (SAXS) for characterizing the structure of surfactant-macromolecule interactions and their complex.

The surfactant-macromolecule interactions (SMI) are one of the most critical topics for scientific research and industrial application. Small-angle X-ray scattering (SAXS) is a powerful tool for comprehensively studying the structural and conformational features of macromolecules at a size ranging from Angstroms to hundreds of nanometers with a time-resolve in milliseconds scale. The SAXS integrative techniques have emerged for comprehensively analyzing the SMI and the structure of their complex in solution. Here, the various types of emerging interactions of surfactant with macromolecules, such as protein, lipid, nuclear acid, polysaccharide and virus, etc. have been systematically reviewed. Additionally, the principle of SAXS and theoretical models of SAXS for describing the structure of SMI as well as their complex has been summarized. Moreover, the recent developments in the applications of SAXS for charactering the structure of SMI have been also highlighted. Prospectively, the capacity to complement artificial intelligence (AI) in the structure prediction of biological macromolecules and the high-throughput bioinformatics sequencing data make SAXS integrative structural techniques expected to be the primary methodology for illuminating the self-assembling dynamics and nanoscale structure of SMI. As advances in the field continue, we look forward to proliferating uses of SAXS based upon its abilities to robustly produce mechanistic insights for biology and medicine.

Study on internal structure of casein micelles in reconstituted skim milk powder.

In the current study, the internal structure of casein micelles (CMs), primary casein cluster, has been studied by size-exclusion chromatography (SEC) coupled with small-angle X-ray scattering (SAXS), isothermal titration calorimetry (ITC), transmission electron microscopy (TEM) and molecular dynamics (MD) simulations. The casein cluster featured a hierarchical structure predominately consisting of αs-CN and ß-CN molecules and a trace of κ-CN. ITC profile showed a typical enthalpogram of CMs with a critical micelle concentration (CMC) of ~0.85 µg/mL. The casein cluster exhibited apparent characteristics of intrinsically disordered proteins (IDPs) with a secondary structure content of 24 % in α-helix, 35.4 % in antiparallel-parallel, 20.2 % in ß-turn and 20.4 % in random coil. SAXS results revealed a slightly elongated and tortuous worm-like conformation for the casein cluster in solution with an aspect ratio of 1.36 and an estimated molecular weight of 162.7 kDa. Further scattering data analysis proposed three coexisted species (αs1-ß-αs2-CN, αs1-CN and αs1-ß-αs2-CN dimer) with a volume fraction of 57.4 %, 30.1 %, and 12.5 % respectively in the casein cluster. TEM observation was consistent with the results of spectra, SAXS and MD that calcium sequestration resulted in a more extended and loose structure, instead, EDTA chelation induced a more compact conformation of the casein cluster.

Gelatin Hydrolysate Hybrid Nanoparticles as Soft Edible Pickering Stabilizers for Oil-In-Water Emulsions.

The aim of this study was to fabricate edible gelatin enzymic digest (GED) based gel particles that can stabilize oil-in-water (O/W) microemulsions. The gel particles were generated by covalent crosslinking, with genipin, the individual protein molecules within tannic acid-induced gelatin hydrolysate (GED-TA) particles. The ability of the genipin-treated GED-TA (GP-GED-TA) to stabilize emulsions was evaluated by Turbiscan analysis and droplet-size changes. For comparison, gelatin hydrolysate (GE) and tannic acid-induced gelatin hydrolysate particles (GED-TA) were used as controls. The mean diameters of GED, GED-TA, and GP-GED-TA particles were 0.68 ± 0.1 nm, 66.2 ± 8.4 nm, and 66.9 ± 7.2 nm, respectively. Nanomechanic analysis using atomic force microscopy(AFM) indicated the average Young's modulu of the GP-GED-TA particles was 760.8 ± 112.0 Mpa, indicating the GP-GED-TA were soft particles. The Turbiscan stability indexes (lower values indicate a more stable emulsion) of the emulsions stabilized with GED, GED-TA, and GP-GED-TA, after storage for three days, were 28.6 ± 1.5, 19.3 ± 4.8, and 4.4 ± 1.3, respectively. After one, or 60 days of storage, the volume-weighted mean diameters (D[4,3]) of oil droplets stabilized by GP-GED-TA were 1.19 ± 0.11 µm and 1.18 ± 0.1 µm, respectively. The D[4,3] of oil droplets stabilized by GED-TA, however, increased from 108.3 ± 5.1 µm to 164.3 ± 19.1 µm during the storage. Overall, the GP-GED-TA gel particles have considerable potential for stabilization of O/W emulsions in food products.

2-Deoxyglucose-Modified Folate Derivative: Self-Assembling Nanoparticle Able to Load Cisplatin.

Folic acid has been widely introduced into nano-drug delivery systems to give nanoparticle-targeted characteristics. However, the poor water solubility of folic acid may hinder the exploitation of its ability to load antineoplastic drugs. In the present study, we designed a new folate derivative (FA-2-DG) synthesized from folic acid and 2-Deoxyglucose (2-DG). The aim of this study was to evaluate the self-assembly characteristics of FA-2-DG, and its ability of loading cisplatin. The critical micelle concentration was 7.94 × 10-6 mol L-1. Fourier transform infrared spectroscopy indicated that hydrogen bonding interaction is a main driving force for the self⁻assembly of FA-2-DG. The particle was stable in pure water or 0.5% bovine serum albumin dispersions. By forming a coordination bond, the particles assembled from FA-2-DG can load cisplatin. The loading efficiency was maximal when the molar ratio of FA-2-DG to cisplatin was 2:1.

Novel Targeted Anti-Tumor Nanoparticles Developed from Folic Acid-Modified 2-Deoxyglucose.

The glucose analog, 2-deoxyglucose (2-DG), specifically inhibits glycolysis of cancer cells and interferes with the growth of cancer cells. However, the excellent water solubility of 2-DG makes it difficult to be concentrated in tumor cells. In this study, a targeted nano-pharmacosome was developed with folic acid-modified 2-DG (FA-2-DG) by using amino ethanol as a cleavable linker. FA-2-DG was able to self-assemble, forming nano-particles with diameters of 10⁻30 nm. The biological effects were evaluated with cell viability assays and flow cytometry analysis. Compared with a physical mixture of folic acid and 2-DG, FA-2-DG clearly reduced cell viability and resulted in cell cycle arrest. A computational study involving docking simulation suggested that FA-2-DG can dock into the same receptor as folic acid, thus confirming that the structural modification did not affect the targeting performance. The results indicated that the nano-pharmacosome consisting of FA-2-DG can be used for targeting in a nano-drug delivery system.

Selenium Deficiency-Induced Apoptosis of Chick Embryonic Vascular Smooth Muscle Cells and Correlations with 25 Selenoproteins.

Selenium deficiency is the major cause of exudative diathesis in chicks. Subcutaneous hemorrhage is one of the typical symptoms of the disease. However, the reason for the occurrence of blood exudation remains unknown. In the present study, the vascular smooth muscle cells (VSMCs) were isolated from 17-day-old broiler chick embryos. Cell viability, cell apoptosis, and intracellular reactive oxygen species level under different concentrations of selenium (0-0.9 µM) were investigated. The mRNA expression levels of 25 selenoproteins and apoptosis-related genes (p53, CytC, Caspase-3, Caspase-8, Bcl-2, and Bax) were also measured. Selenium deficiency significantly decreased cell viability and increased cell apoptosis (p < 0.05). Supplementation with selenium could alleviate these changes. In general, at all levels of selenium addition, Gpx1, Gpx3, Gpx4, SepW1, and Sep15 mRNAs were all highly expressed in VSMCs, whereas Gpx2, Dio1, SepN1, SelO, and SelPb were at lower levels. There was a high correlation between Gpx2, Gpx3, Gpx4, Dio1, Txnrd1, Txnrd2, and Txnrd3 gene expression. Additionally, Gpx3, Gpx4, Dio1, Txnrd1, Txnrd2, Txnrd3, SelS, and SelPb showed a strong negative correlation with pro-apoptotic gene Caspase-3 as well as a strong positive correlation with anti-apoptotic gene Bcl-2, especially SelI (r = 0.913 and r = 0.929, p < 0.01). These results suggest that selenium deficiency could induce VSMC apoptosis, and several selenoproteins may be involved in the development of apoptosis. Our findings provide information on the molecular mechanism of vascular injury by selenium deficiency.

Effects of a Tripeptide Iron on Iron-Deficiency Anemia in Rats.

This study aims to investigate the effects of a tripeptide iron (REE-Fe) on iron-deficiency anemia rats. Sprague-Dawley rats were randomly divided into seven groups: a normal control group, an iron-deficiency control group, and iron-deficiency groups treated with ferrous sulfate (FeSO4), ferrous glycinate (Fe-Gly), or REE-Fe at low-, medium-, or high-dose groups. The rats in the iron-deficiency groups were fed on an iron-deficient diet to establish iron-deficiency anemia (IDA) model. After the model established, different iron supplements were given to the rats once a day by intragastric administration for 21 days. The results showed that REE-Fe had effective restorative action returning body weight, organ coefficients, and hematological parameters in IDA rats to normal level. In addition, comparing with FeSO4 or Fe-Gly, high-dose REE-Fe was more effective on improving the levels of renal coefficient, total iron-binding capacity, and transferrin. Furthermore, the liver hepcidin messenger RNA (mRNA) expression in the high-dose group was significantly higher (p < 0.05) than that in the FeSO4 or Fe-Gly group and showed no significant difference (p > 0.05) with the normal control group. The findings suggest that REE-Fe is an effective source of iron supplement for IDA rats and might be exploited as a new iron fortifier.

Modulation of gut microbiota by polyphenols from adlay (Coix lacryma-jobi L. var. ma-yuen Stapf.) in rats fed a high-cholesterol diet.

This study aimed to evaluate the beneficial effects of polyphenol extract of adlay (Coix lacryma-jobi L. var. ma-yuen Stapf.) (PEA) on gut microbiota in rats fed a high-cholesterol diet (HCD). Rats were fed HCD containing 1% cholesterol (w/w), with or without a daily intragastric supplement of 200 mg/kg body weight PEA. Results showed that PEA significantly ameliorated increases in serum cholesterol and low-density lipoprotein cholesterol values and significantly restored high-density lipoprotein cholesterol values. The HCD-induced imbalance of gut microflora was modulated by the consumption of PEA. Most bacterial strains influenced by PEA are related to host lipid metabolism. The abundances of one Erysipelotrichales strains and two Clostridia strains were lower in the PEA group than in the control. Phenolic compounds in PEA were identified by HPLC. The findings indicate that PEA may be a useful dietary supplement in the treatment of elevated cholesterol levels and the imbalanced gut microbial ecology.