Ovotransferrin Exhibits Osteogenic Activity Partially via Low-Density Lipoprotein Receptor-Related Protein 1 (LRP1) Activation in MC3T3-E1 Cells

Circ-SPATA13 regulates the osteogenic differentiation of human periodontal ligament stem cells through the miR-485-5p_R + 1/BMP7 axis

BACKGROUND

Human periodontal ligament stem cells (PDLSCs) are widely available and have strong osteogenic differentiation ability, which makes them promising tools for bone regeneration. Circular RNAs (circRNAs) play a variety of functions in the process of cell differentiation and are potential therapeutic targets. Here, we identified a new circRNA, circ-SPATA13, and found that it was highly positively correlated with the osteogenic differentiation of PDLSCs. Therefore, in this study, we revealed the significance and mechanism of circ-SPATA13 in the osteogenic differentiation of PDLSCs.

METHODS

PDLSCs were isolated from third molars with incomplete apical development and induced to undergo chondrogenic, adipogenic, or osteogenic differentiation. Surface markers were detected via flow cytometry. Proliferation was assessed with EdU and CCK-8 assays. The circ-SPATA13 and miR-485-5p_R + 1-mediated control of mineral deposition was evaluated through alizarin red and alkaline phosphatase staining. Osteogenesis-related factor expression was detected through western blotting, immunofluorescence, and qRT-PCR. Fluorescence in situ hybridization was used to examine circ-SPATA13 localization within PDLSCs. The relationships among circ-SPATA13, miR-485-5p_R + 1, and BMP7 during PDLSCs osteogenesis were assessed through western blotting, qRT-PCR, dual-luciferase assay, rescue experiment, and bioinformatics approaches.

RESULTS

Primary PDLSCs expressing mesenchymal stem cell surface markers were isolated. Circ-SPATA13 was identified and found to have no impact on PDLSC proliferation, whereas it was a positive regulator of their osteogenic differentiation, a process which was antagonized by miR-485-5p_R + 1. Dual-luciferase reporter assays revealed that circ-SPATA13 was able to function as a molecular sponge to sequester miR-485-5p_R + 1 within PDLSCs, while this miRNA was able to bind to the 3'-UTR of the target mRNA BMP7. In rescue experiments, circ-SPATA13 was confirmed to regulate the osteogenic differentiation of PDLSCs via this miR-485-5p_R + 1/BMP7 axis. Moreover, in vivo experiments in rats demonstrated that the overexpression of circ-SPATA13 in PDLSCs was associated with the promotion of bone formation in a skull defect model system.

CONCLUSION

These data supported the osteogenic functions of circ-SPATA13 in PDLSCs. Mechanistically, this circRNA was found to function as a molecular sponge for miR-485-5p_R + 1, in turn targeting BMP7 to promote the osteogenic differentiation of PDLSCs. This circ-SPATA13/miR-485-5p_R + 1/BMP7 axis may be a novel target for treatments promoting PDLSCs osteogenic differentiation.

Impact of Vitamin D Status and Nutrition on the Occurrence of Long Bone Fractures Due to Falls in Elderly Subjects in the Vojvodina Region of Serbia

Bone fractures are a significant public health issue among elderly subjects. This study examines the impact of diet and vitamin D status on the risk of long bone fractures due to falls in elderly subjects in Vojvodina, Serbia. Conducted at the University Clinical Center of Vojvodina in autumn/winter 2022-2023, the study included 210 subjects >65 years: 105 (F: 80/M: 15) with long bone fractures due to falls and 105 (F: 80/M: 15) controls. Groups were similar regarding age and BMI. Dietary intakes (by two 24-h recalls) and serum vitamin D levels were analyzed. The fracture group had a significantly lower median daily vitamin D intake (1.4 μg/day vs. 5.8 μg/day), intake of calcium, energy, proteins, fats, fibers, dairy products, eggs, fish, edible fats/oils, and a higher intake of sweets (p < 0.001 for all). Serum vitamin D levels were significantly lower in the fracture group (40.0 nmol/L vs. 76.0 nmol/L, p < 0.001). Logistic regression identified serum vitamin D as the most important protective factor against fractures, and ROC curve analysis indicated that serum vitamin D levels > 50.5 nmol/L decreased fracture risk. Nutritional improvements (increased intake of vitamin D and protein sources such as fish, eggs, and dairy), increased sun exposure, and routine vitamin D supplementation during winter are advised.

Ovotransferrin, an alternative and potential protein for diverse food and nutritional applications

Ovotransferrin(OVT)is a protein found in many types of egg white and has a wide range of functional properties. It has 50% homology with human/bovine lactoferrin, and is expected to be one of the most important alternative proteins for use in food and nutritional applications. This paper mainly reviews the structural characteristics and chemical properties of OVT, as well as its extraction and purification methods. It also systematically describes the various biological activities of OVT and its applications in food and medical industries. The challenges and limitations in the research of OVT were suggested. This review recommends some possible methods such as nanoparticle carriers and microencapsulation to improve the bioavailability and stability of OVT. In addition, this review highlights several strategies to overcome the limitations of OVT in terms of preparation and purification. This review systematically summarizes the recent advances in OVT and will provide guidance for the its development for food and nutritional applications.

Ovalbumin Hydrolysates Enhance Skeletal Muscle Insulin-Dependent Signaling Pathway in High-Fat Diet-Fed Mice

Egg white hydrolysates (EWH) and ovotransferrin-derived peptides have distinct beneficial effects on glucose metabolism. This research aims to investigate whether ovalbumin hydrolysates (OVAHs), without ovotransferrin can improve insulin signaling pathway in high-fat diet (HFD)-fed mice. Two types of ovalbumin hydrolysates were produced, either using thermoase (OVAT), or thermoase + pepsin (OVATP). Both OVAHs-supplemented groups exhibited lower body weight gain (P < 0.001) and enhanced oral glucose tolerance (P < 0.05) compared with HFD. Moreover, diet supplementation with either hydrolysate increased the insulin-stimulated activation of protein kinase B (AKT) and insulin receptor β (IRβ) (P < 0.0001) in skeletal muscle. In conclusion, OVAHs improved glucose tolerance and insulin-dependent signaling pathway in HFD-fed mice.

l-thyroxine attenuates extracellular Hsp90α-induced vascular endothelial calcification in diabetes mellitus, as revealed by parallel metabolic profiles

BACKGROUND AND AIMS

Diabetic atherosclerotic vascular disease is characterized by extensive vascular calcification. However, an elevated blood glucose level alone does not explain this pathogenesis. We investigated the metabolic markers underlying diabetic atherosclerosis and whether extracellular Hsp90α (eHsp90α) triggers vascular endothelial calcification in this particular metabolic environment.

METHODS

A parallel human/animal model metabolomics approach was used. We analyzed 40 serum samples collected from 24 patients with atherosclerosis and from the STZ-induced ApoE-/- mouse model. A multivariate statistical analysis of the data was performed, and mouse aortic tissue was collected for the assessment of plaque formation. In vitro, the effects of eHsp90α on endothelial cell calcification were assessed by serum analysis, Western blotting and immunoelectron microscopy.

RESULTS

Diabetic ApoE-/- mice showed more severe plaque lesions and calcification damage. Stearamide, oleamide, l-thyroxine, l-homocitrulline and l-citrulline are biomarkers of diabetic ASVD; l-thyroxine was downregulated in both groups, and the thyroid sensitivity index was correlated with serum Hsp90α concentration. In vitro studies showed that eHsp90α increased Runx2 expression in endothelial cells through the LRP1 receptor. l-thyroxine reduced the increase in Runx2 levels caused by eHsp90α and affected the distribution and expression of LRP1 through hydrogen bonding with glutamine at position 1054 in the extracellular segment of LRP1.

CONCLUSIONS

This study provides a mechanistic link between characteristic serum metabolites and diabetic atherosclerosis and thus offers new insight into the role of extracellular Hsp90α in promoting vascular calcification.

Temporal transcriptome features identify early skeletal commitment during human epiphysis development at single-cell resolution

Human epiphyseal development has been mainly investigated through radiological and histological approaches, uncovering few details of cellular temporal genetic alternations. Using single-cell RNA sequencing, we investigated the dynamic transcriptome changes during post-conception weeks (PCWs) 15-25 of human distal femoral epiphysis cells. We find epiphyseal cells contain multiple subtypes distinguished by specific markers, gene signatures, Gene Ontology (GO) enrichment analysis, and gene set variation analysis (GSVA). We identify the populations committed to cartilage or ossification at this time, although the secondary ossification centers (SOCs) have not formed. We describe the temporal alternation in transcriptional expression utilizing trajectories, transcriptional regulatory networks, and intercellular communication analyses. Moreover, we find the emergence of the ossification-committed population is correlated with the COL2A1-(ITGA2/11+ITGB1) signaling. NOTCH signaling may contribute to the formation of cartilage canals and ossification via NOTCH signaling. Our findings will advance the understanding of single-cell genetic changes underlying fetal epiphysis development.

Peptides GWN and GW protect kidney cells against Dasatinib induced mitochondrial injury in a SIRT1 dependent manner

Dasatinib, a small-molecule drug used as a treatment for chronic myeloid leukemia induces mitochondrial damage in embryonic kidney (293 T) cells (p < 0.05). This dasatinib induced mitochondrial injury in kidney cells was mitigated by H3K36me3 activating ovotransferrin-derived peptides GWN and GW. Pre-treatment of kidney cells with GWN and GW lead to elevation of cytoprotective sirtuins, SIRT1 and SIRT3, in response to dasatinib injury (p < 0.01) in vitro. Both peptides, GWN and GW, also reversed dasatinib induced the loss of mitochondria in kidney cells and promoted the protein expression of COX4 (p < 0.01). Mechanistically, loss of SIRT1 in kidney cells abolished the ability of GWN and GW to protect embryonic kidney cells against dasatinib injury in vitro. Overall, we provide cell based evidence showing that GWN and GW exhibit the ability to protect mitochondria against dasatinib-induced mitochondrial damage in a SIRT1 dependent manner.

Novel Soy Peptide CBP: Stimulation of Osteoblast Differentiation via TβRI-p38-MAPK-Depending RUNX2 Activation

DEDEQIPSHPPR, the calcium-binding peptide (CBP) identified in soy yogurt, was proven to be a potential cofactor in osteoporosis prevention in our previous study, but the mechanism was unknown. In this study, the activity of alkaline phosphatase (ALP) and osteocalcin (OCN), the regulation of RUNX2, and the expression of TβRI were investigated to elucidate the underlying mechanism. The results show that CBP upregulated ALP activity and OCN concentration and increased the expression of RUNX2 and the activation of the MAPK signaling pathway. Similarly, the expression of osteogenesis-related genes in osteoblasts also increased upon CBP treatment. Moreover, the CBP-induced enhancement of ALP activity and phosphorylation levels in the p38 pathway was inhibited by treatment with a p38 inhibitor (SB203538) and TβRI inhibitor (SB431542), respectively, suggesting that p38 and TβRI were involved in the osteogenic action. Based on the signaling pathways, the intracellular calcium concentration was significantly elevated by CBP, which was correlated with the increased behavioral functions and the relative fluorescence intensity of the bone mass. These findings suggest that CBP stimulates osteoblast differentiation and bone mineralization through the activation of RUNX2 via mechanisms related to the TβRI-p38-MAPK signaling pathways, further highlighting CBP's important potential for treating osteoporosis.

Mitofusion is required for MOTS-c induced GLUT4 translocation

MOTS-c (mitochondrial ORF of the twelve S-c) is a 16-amino-acid mitochondrial peptide that has been shown to counter insulin resistance and alleviate obesity in vivo. However, the mechanisms involved in the pharmacological action of MOTS-c remain elusive. Based on the ability of MOTS-c to improve insulin resistance and promote cold adaptation, we hypothesized that MOTS-c might play a role in boosting the number of mitochondria in a cell. We found that treatment of mammalian cells with MOTS-c increased protein levels of TFAM, COX4, and NRF1, which are markers for mitochondrial biogenesis. However, flow cytometry analysis using MitoTracker Green revealed a sharp reduction in the mitochondrial count after MOTS-c treatment. We then anticipated possible synchronized activation of mitofusion/mitochondrial fusion by MOTS-c following the onset of mitochondrial biogenesis. This was confirmed after a significant increase in protein levels two GTPases, OPA1, and MFN2, both vital for the fusion of mammalian mitochondria. Finally, we found that inhibition of the two GTPases by TNFα abrogated the ability of MOTS-c to prompt GLUT4 translocation and glucose uptake. Similar results were obtained by siRNA KD of MFN2 as well. Our results reveal for the first time a pathway that links mitofusion to MOTS-c-induced GLUT4 translocation.

Functional properties of ovotransferrin from chicken egg white and its derived peptides: a review

With emerging trends in the food and pharmaceutical industries, potential applications of egg-derived bioactive compounds were recognized. Ovotransferrin is a major egg white functional protein responsible for multiple bioactivities. The objectives of this review are to provide scientific evidence of the functional properties of chicken ovotransferrin and its derived peptides and to identify future research approaches and applications. Various easy, economical, and non-toxic methods have been reported to produce ovotransferrin with high yield and purity, and chemical and enzymatic approaches have been employed to release bioactive peptides. The native ovotransferrin is known to have antimicrobial, antioxidant, anticancer, and immunomodulatory activities. The peptides produced from ovotransferrin also are reported to have antioxidant, antimicrobial, antihypertensive, and anticancer properties. However, little or no application of these compounds in the food and pharmaceutical areas is available yet. Therefore, the practical application of OTF in nutraceutical and pharmaceutical areas are among the emerging areas of research.