Characteristics and osteogenic mechanism of glycosylated peptides-calcium chelate

Molecular interactions and physiological effects of oyster-derived synthetic peptide-calcium complex: Insight in improving the bone growth and health

In this study, the oyster-derived synthetic peptide VAPEEHPV (V) was utilized to prepare the VCa complex with calcium ions. The results from frontier orbital analysis, molecular docking, and molecular dynamics simulations indicated that the primary binding sites were the carboxyl oxygen of Glu and the amide bond oxygen of Ala and Pro, while the VCa complex demonstrated stability in aqueous environments. Furthermore, various characterization techniques revealed that, in comparison to peptide V, VCa exhibited a decrease in UV absorption intensity and β-sheet content, an increase in particle size (from 720 to 1265 nm), enhanced thermal stability, and a rougher surface morphology. In a calcium deficiency mouse model, a medium dose of VCa improved the structure of the small intestinal villi, increased serum calcium levels (4.11 mmol/L) and phosphorus levels (2.01 mmol/L), and reduced alkaline phosphatase (AKP) levels (49.4 King Units/100 mL). Regarding bone quality, a high dose of VCa, superior to CaCO3, significantly increased bone calcium content (femur: 178.57 mg/g, tibia: 178.59 mg/g) and bone density (femur: 1.67 g/cm3, tibia: 1.82 g/cm3). The deterioration of osteoclasts and tissue inflammation induced by calcium deficiency was markedly improved, and the thickness of the bone cortex increased to 713.91 μm.

Identification of a novel calcium-binding peptide from Lentinula edodes and structure, stability and absorption evaluation of its calcium chelate

BACKGROUND

Peptide-Ca chelates are promising calcium supplements. Lentinula edodes (LE) is rich in amino acids with calcium-binding ability, and so it is hypothesized that it can be used to develop peptide-Ca chelates. Additionally, aiming to save time, molecular docking, using Ca2+ or calcium sensing receptor (CaSR) (a regulator of calcium homeostasis) as target, has been applied in the screening of calcium-binding peptides (CBP). In the present study, LE CBP was separated and identified by traditional methods. The optimal CBP was further screened through docking. Then, the structure, stability and calcium absorption of LEVEIHA-Ca were evaluated.

RESULTS

The LE protein hydrolysate was sequentially purified using ultrafiltration followed by anion-exchange chromatography; two subfractions (F33 and F34) of LE CBP were obtained, both of which exhibited higher calcium binding rate. Eight potential CBP in the two subfractions were identified, and leucine-glutamic acid-valine-glutamic acid-histidine-isoleucine-alanine (LEVEHIA), showing the highest affinity with Ca2+ and CaSR, was selected by docking assay. The prepared chelate, LEVEIHA-Ca, formed more compact and larger micelles (1125 ± 2 nm) with lower zeta potential (-20.1 ± 0.3 mv) compared to LEVEHIA. Functional groups including COO-, NH, CN and CO were involved in the chelation between LEVEIHA and Ca2+. LEVEIHA-Ca was tolerant to high temperature, and most calcium (87 ± 4%) was retained after gastrointestinal digestion. LEVEIHA-Ca exhibited better promoting effects on calcium absorption than casein phosphopeptides-Ca.

CONCLUSION

LE can be used to prepare peptide-chelate with high calcium absorption. © 2025 Society of Chemical Industry.

Binding mechanism, digestive stability, and cellular interactions of a potential organic Iron supplement: Fermented scallop skirt peptide (DDDHPGIF)-Iron complex

The fermentation-derived scallop skirt peptide (DDDHPGIF) with strong ferrous ion-binding capability (95.17 ± 0.30 %) was identified in our previous study. However, the structure-function relationship of the peptide prepared by fermentation was still unclear. This study elucidated the binding mechanism, digestive characteristics and transport modes of the fermentation-derived peptide. We hypothesized that the binding process involved the formation of coordination bonds between the carboxyl groups and ferrous ions, followed by self-assembly through intermolecular hydrogen bonds, resulting in a stable and uniform complex. Furthermore, DDDHPGIF and its ferrous chelate (DDDHPGIF-Fe) had excellent digestion stability, with retention rates of 95.09 % and 93.08 %, respectively. The retention rate was the highest of the available reports, showing the unique advantages of the peptide sequence. Finally, we inferred the transport mechanisms of DDDHPGIF and DDDHPGIF-Fe included active transport and endocytosis. This study provides a theoretical basis for developing ferrous chelating peptides from aquatic by-products using microbial methods.

A cross-sectional study comparing machine learning and logistic regression techniques for predicting osteoporosis in a group at high risk of cardiovascular disease among old adults

BACKGROUND

Osteoporosis has become a significant public health concern that necessitates the application of appropriate techniques to calculate disease risk. Traditional methods, such as logistic regression,have been widely used to identify risk factors and predict disease probability. However,with the advent of advanced statistics techniques,machine learning models offer promising alternatives for improving prediction accuracy. What's more, studies that use risk factors and prediction models for osteoporosis in high-risk groups for cardiovascular diseases are scarce. We aimed to explore the risk factors and disease probability of osteoporosis by comparing logistic regression with four machine learning models. By doing so,we seek to provide insights into the most effective methods for osteoporosis risk assessment and contribute to the development of tailored prevention strategies at high risk of cardiovascular disease among old adults.

METHODS

We carried out a cross-sectional investigation of a high-risk group in cardiovascular patients. A logistic regression model and four common machine learning methods,DT,RF,SVM,and XGBoost were implemented to create a prediction model using information from 211 participants who met the inclusion requirements. Metrics for calibration and discrimination were used to compare the models.

RESULTS

In total,211 patients were enrolled. The AUCs were 0.751 for the logistic regression model,0.72 for the SVM model,0.70 for the random forest model,0.697 for the model XGBoost,and 0.69 for the decision tree model. The logistic regression model outperforms other models for machine learning. According to the logistic regression model,there were nine predictors,including age,sex,glucose,TG (triglyceride),fracture history,stroke history,and CNV (copy number variation) nssv659422, and low-sodium salt. A well-calibrated result of 0.199 on the Brier scale. The findings of the internal validation demonstrated the high degree of repeatability of the prediction model employed in this study.

CONCLUSIONS

In this study, we discovered that when predicting osteoporosis,a number of machine learning techniques fell short of logistic regression. In a specific population, we have innovatively developed a risk prediction model for osteoporosis events that integrates genetic and environmental factors, is an effective tool for assessing osteoporosis risk and can serve as the basis for specialized intervention approaches.

Novel Insights Into Peptide-Calcium Chelates From Lentinula edodes: Preparation and Its Structure, Stability, and Calcium Transport Analysis

Peptide-Ca chelates are innovative calcium supplements. Lentinula edodes possesses nutritional advantages for preparing calcium-binding peptides (CBPs), although there are limited studies on this subject. Therefore, this paper investigated the optimal condition for preparing Lentinula edodes CBPs and Lentinula edodes peptide-calcium chelates (LP-Ca), along with analyzing their microstructure, calcium-binding mechanisms, stability, and calcium transporting efficacy. The optimal protease and hydrolysis time for preparing CBPs were neutral protease and 3 h, respectively. The optimized parameters for LP-Ca preparation were as follows: pH9, time 50 min, mass ratio of peptide/CaCl2 5:1, and temperature 65°C. The chelates contain 4.23% ± 0.01% Ca. After chelation, Glu, Asp, Lys, Ser, His, and Cys were enriched. LP-Ca possessed a rough and porous structure, exhibiting a pronounced calcium signal. -COO-, C=O, and N-H groups were contributed to the chelation, with calcium primarily existing in an amorphous form. LP-Ca exhibited enhanced thermal stability and retained most of the calcium (62.33% ± 4.51%) after digestion, and calcium transportation was enhanced in the LP-Ca group (9.57 ± 0.60 μg). Collectively, LP-Ca are studied for the first time and the study is of great significance for developing novel calcium supplements.

Preparation and characterization of white shrimp hydrolysate-xylooligosaccharide Maillard products and their in vivo promotive effects of zinc absorption in mice

The Maillard reaction products, as a kind of glycosylation-based reaction, possess the metal-chelating ability. In this study, the white shrimp hydrolysate (WH) and xylooligosaccharides (XOS) were used to prepare the Maillard reaction product-zinc complex (WH-XOS-MR-Zn) with zinc ions. The Maillard reaction conditions, such as pH level, temperature, reaction time, and the ratio of XOS to WH, were selected by testing the products' zinc-chelating capacity, while the optimized conditions (zinc-chelating capacity = 64.8%, pH = 7, 110 °C, 180 min, XOS : WH = 2) were finally determined. The interactions between WH-XOS-MR and zinc were confirmed and characterized by various kinds of techniques and triggered new peaks of fluorescent signals. The addition of zinc in WH-XOS-MR induced the proportion changes of secondary structures, including the decrease of β-sheets (8.16%) and the increase of β-turns (5.9%) and random coils (2.23%). The addition of zinc changed the morphological surface appearance of WH-XOS-MR and the crystal signal was completely covered in the WH-XOS-MR-Zn complex involved in the chelation with carbonyl and amino groups. The high-dose and medium-dose of the WH-XOS-MR-Zn complex showed higher promotive effects on zinc absorption (11.89 and 11.05 umol L-1, respectively) and medium-dose recovered values of AKP (liver and serum: 7.15 and 12.53 U mL-1), SOD (liver, kidney and serum: 59.84, 7.86 and 13.61 U mL-1) and GSH-Px (203.22 U per mgprot), damage to testicular tissues, damage to the intact neuron cells in the hippocampus region (CA1: 54 to 61, CA3: 67 to 136, DG: 219-353), and intestinal inflammation compared with the zinc-deficient mice. These findings showed therapeutic benefits of Maillard products on intestinal health and cellular structures.

Biomimetic Bone-Like Composite Hydrogel Scaffolds Composed of Collagen Fibrils and Natural Hydroxyapatite for Promoting Bone Repair

Bone is a complex organic-inorganic composite tissue composed of ∼30% organics and ∼70% hydroxyapatite (HAp). Inspired by this, we used 30% collagen and 70% HAp extracted from natural bone using the calcination method to generate a biomimetic bone composite hydrogel scaffold (BBCHS). In one respect, BBCHS, with a fixed proportion of inorganic and organic components similar to natural bone, exhibits good physical properties. In another respect, the highly biologically active and biocompatible HAp from natural bone effectively promotes osteogenic differentiation, and type I collagen facilitates cell adhesion and spreading. Additionally, the well-structured porosity of the BBCHS provides sufficient growth space for bone marrow mesenchymal stem cells (BMSCs) while promoting substance exchange. Compared to the control group, the new bone surface of the defective location in the B-HA70+Col group is increased by 3.4-fold after 8 weeks of in vivo experiments. This strategy enables the BBCHS to closely imitate the chemical makeup and physical structure of natural bone. With its robust biocompatibility and osteogenic activity, the BBCHS can be easily adapted for a wide range of bone repair applications and offers promising potential for future research and development.

Preparation, characterization, and property evaluation of Hericium erinaceus peptide-calcium chelate

Recently, owing to the good calcium bioavailability, peptide-calcium chelates made of various foods have been emerging. Hericium erinaceus, an edible fungus, is rich in proteins with a high proportion of calcium-binding amino acids. Thus, mushrooms serve as a good source to prepare peptide-calcium chelates. Herein, the conditions for hydrolyzing Hericium erinaceus peptides (HP) with a good calcium-binding rate (CBR) were investigated, followed by the optimization of HP-calcium chelate (HP-Ca) preparation. Furthermore, the structure of the new chelates was characterized along with the evaluation of gastrointestinal stability and calcium absorption. Papain and a hydrolysis time of 2 h were selected for preparing Hericium erinaceus peptides, and the conditions (pH 8.5, temperature 55°C, time 40 min, and mass ratio of peptide/CaCl2 4:1) were optimal to prepare HP-Ca. Under this condition, the chelates contained 6.79 ± 0.13% of calcium. The morphology and energy disperse spectroscopy (EDS) analysis showed that HP-Ca was loose and porous, with an obvious calcium element signal. The ultraviolet-visible (UV) absorption and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that calcium possibly chelates to HP via interaction with free -COO- from acidic amino acids and C = O from amide. HP-Ca displayed good stability against stimulated gastrointestinal digestion. Moreover, HP-Ca significantly improved the calcium absorption by Caco-2 epithelial cells. Thus, HP-Ca is a promising Ca supplement with high calcium bioavailability.

Talin mechanotransduction in disease

Talin protein (Talin 1/2) is a mechanosensitive cytoskeleton protein. The unique structure of the Talin plays a vital role in transmitting mechanical forces. Talin proteins connect the extracellular matrix to the cytoskeleton by linking to integrins and actin, thereby mediating the conversion of mechanical signals into biochemical signals and influencing disease progression as potential diagnostic indicators, therapeutic targets, and prognostic indicators of various diseases. Most studies in recent years have confirmed that mechanical forces also have a crucial role in the development of disease, and Talin has been found to play a role in several diseases. Still, more studies need to be done on how Talin is involved in mechanical signaling in disease. This review focuses on the mechanical signaling of Talin in disease, aiming to summarize the mechanisms by which Talin plays a role in disease and to provide references for further studies.

A critical review of a typical research system for food-derived metal-chelating peptides: Production, characterization, identification, digestion, and absorption

In the past decade, food-derived metal-chelating peptides (MCPs) have attracted significant attention from researchers working towards the prevention of metal (viz., iron, zinc, and calcium) deficiency phenomenon by primarily inhibiting the precipitation of metals caused by the gastrointestinal environment and exogenous substances (including phytic and oxalic acids). However, for the improvement of limits of current knowledge foundations and future investigation directions of MCP or their derivatives, several review categories should be improved and emphasized. The species' uniqueness and differences in MCP productions highly contribute to the different values of chelating ability with particular metal ions, whereas comprehensive reviews of chelation characterization determined by various kinds of technique support different horizons for explaining the chelation and offer options for the selection of characterization methods. The reviews of chelation mechanism clearly demonstrate the involvement of potential groups and atoms in chelating metal ions. The discussions of digestive stability and absorption in various kinds of absorption model in vitro and in vivo as well as the theory of involved cellular absorption channels and pathways are systematically reviewed and highlighted compared with previous reports as well. Meanwhile, the chelation mechanism on the molecular docking level, the binding mechanism in amino acid identification level, the utilizations of everted rat gut sac model for absorption, and the involvement of cellular absorption channels and pathway are strongly recommended as novelty in this review. This review makes a novel contribution to the literature by the comprehensive prospects for the research and development of food-derived mineral supplements.

Novel Ca-Chelating Peptides from Protein Hydrolysate of Antarctic Krill (Euphausia superba): Preparation, Characterization, and Calcium Absorption Efficiency in Caco-2 Cell Monolayer Model

Antarctic krill (Euphausia superba) is the world's largest resource of animal proteins and is thought to be a high-quality resource for future marine healthy foods and functional products. Therefore, Antarctic krill was degreased and separately hydrolyzed using flavourzyme, pepsin, papain, and alcalase. Protein hydrolysate (AKH) of Antarctic krill prepared by trypsin showed the highest Ca-chelating rate under the optimized chelating conditions: a pH of 8.0, reaction time of 50 min, temperature of 50 °C, and material/calcium ratio of 1:15. Subsequently, fourteen Ca-chelating peptides were isolated from APK by ultrafiltration and a series of chromatographic methods and identified as AK, EAR, AEA, VERG, VAS, GPK, SP, GPKG, APRGH, GVPG, LEPGP, LEKGA, FPPGR, and GEPG with molecular weights of 217.27, 374.40, 289.29, 459.50, 275.30, 300.36, 202.21, 357.41, 536.59, 328.37, 511.58, 516.60, 572.66, and 358.35 Da, respectively. Among fourteen Ca-chelating peptides, VERG presented the highest Ca-chelating ability. Ultraviolet spectrum (UV), Fourier Transform Infrared (FTIR), and scanning electron microscope (SEM) analysis indicated that the VERG-Ca chelate had a dense granular structure because the N-H, C=O and -COOH groups of VERG combined with Ca2+. Moreover, the VERG-Ca chelate is stable in gastrointestinal digestion and can significantly improve Ca transport in Caco-2 cell monolayer experiments, but phytate could significantly reduce the absorption of Ca derived from the VERG-Ca chelate. Therefore, Ca-chelating peptides from protein hydrolysate of Antarctic krill possess the potential to serve as a Ca supplement in developing healthy foods.

Preparation of a cattle bone collagen peptide-calcium chelate by the ultrasound method and its structural characterization, stability analysis, and bioactivity on MC3T3-E1 cells

This study was designed to prepare a cattle bone-derived collagen peptide-calcium chelate by the ultrasound method (CP-Ca-US), and its structure, stability, and bioactivity on MC3T3-E1 cells were characterized. Single-factor experiments optimized the preparation conditions: ultrasound power 90 W, ultrasound time 40 min, CaCl₂/peptides ratio 1/2, pH 7. Under these conditions, the calcium-chelating ability reached 39.48 μg mg^-1. The result of Fourier transform-infrared spectroscopy indicated that carboxyl oxygen and amino nitrogen atoms were chelation sites. Morphological analysis indicated that CP-Ca-US was characterized by a porous surface and large particles. Stability analysis demonstrated that CP-Ca-US was stable in the thermal environment and under intestinal digestion. CP-Ca-US showed more stability in gastric juice than the chelate prepared by the hydrothermal method. Cell experiments indicated that CP-Ca-US increased osteoblast proliferation (proliferation rate 153% at a concentration of 300 μg mL^-1) and altered the cell cycle. Significantly, CP-Ca-US enhanced calcium absorption by interacting with calcium-sensing receptors and promoted the mineralization of MC3T3-E1 cells. This study provides the scientific basis for applying the ultrasound method to prepare peptide-calcium chelates and clarifies the positive role of chelates in bone building.