Bone marrow mesenchymal stem cell-derived extracellular vesicles containing miR-497-5p inhibit RSPO2 and accelerate OPLL

Network study of miRNA regulating traumatic heterotopic ossification

OBJECTIVE

Objective: To identify and analyze the microRNAs that are expressed differently (DE-miRNAs) and forecast their potential roles in the pathophysiological process of traumatic heterotopic ossification (THO).

METHODS

We conducted RNA sequencing on six samples of normal bone and THO tissues from the patients and conducted differential expression analysis of miRNA. The biological activities of the target genes of the differentially expressed microRNAs (DE-miRNAs) were investigated using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The miRNA-mRNA network was constructed using Cytoscape software, incorporating miRNAs with varying expression levels and their corresponding target genes.

RESULTS

In comparison to the normal control group, a total of 84 differentially expressed microRNAs (p<0.05, |log2FC|>1) were identified, with 27 microRNAs showing up-regulation and 57 microRNAs showing down-regulation. The functional enrichment analysis revealed that the target genes of the de-mirna were primarily enriched in biological processes such as the regulation of protein stability and the management of neuromuscular process balance. Additionally, a miRNA-mRNA expression regulatory network was established. The RT-qPCR analysis revealed that miR-142-3p, miR-150-5p, miR-421, miR-625-5p, miR-675-5p, and miR-940 exhibited a decrease in expression levels in THO tissues. Nevertheless, the expression levels of miR-181c-3p, miR-320c, miR-497-5p, and miR-99a-5p were increased in THO tissues.

CONCLUSIONS

Our investigation has uncovered the expression patterns and projected the potential activities of differentially expressed microRNAs (DE-miRNAs) in human THO. This research may contribute to a better understanding of the underlying mechanisms and offer new possibilities for therapeutic targets in THO.

The Hedgehog-GLI1 Pathway Regulates Osteogenic Differentiation of Human Cervical Posterior Longitudinal Ligament Cells by BMP Signalling Pathway

Cervical ossification of the posterior longitudinal ligament (OPLL) is an ectopic ossification disorder characterised by endochondral ossification. Its aetiology remains to be fully elucidated. This study aimed to clarify its pathogenesis through RNA sequencing of primary cells cultured from patients without cervical OPLL (control, PLL) and patients with cervical OPLL (disease, OPLL). We revealed for the first time the role of GLI1 within OPLL cells. Functional experiments indicated that GLI1, acting as a pivotal mediator between the upstream Hedgehog pathway and downstream BMP pathway, influences the pathogenesis of OPLL. The positive/negative effects on osteogenic differentiation following activation/inhibition of the Hedgehog pathway can be rescued by manipulating GLI1 expression. Overexpression of GLI1 activates BMP signalling, enhancing osteogenic capacity in PLL cells, while GLI1 knockdown suppresses BMP signal transduction, attenuating osteogenic differentiation in OPLL cells. Our findings highlight the significant role of the canonical Hedgehog signalling pathway and its interaction with the BMP pathway in the pathogenesis of OPLL.

A new strategy for drug delivery systems in oral diseases using stem cell-derived extracellular vesicles: review and new perspectives

Extracellular vesicles (EVs) are membrane vesicles derived from cells and serve as an endogenous mechanism for intercellular communication. Since the discovery of their capacity to effectively transfer biological information, their potential as drug delivery vehicles has garnered significant scientific interest. Particularly, EVs derived from mesenchymal cells (MSC-EVs) have emerged as a highly promising method for drug delivery. They can transport bioactive molecules, such as nucleic acids, lipids, and proteins, and possess the ability to modulate immune responses, transmit information, and target specific cells. EVs offer several advantages over conventional drug delivery systems, including their capacity to traverse natural barriers, inherent cell targeting capabilities, and stability in circulation. Compared to their parent cells, EVs exhibit low immunogenicity, ease of storage and transport, and a reduced risk of tumorigenesis. The diagnosis and treatment of oral diseases often involve invasive measures, and MSC-EVs have demonstrated initial efficacy in oral disease treatment. This review explores the application of MSC-EVs in maxillofacial tissue regeneration, periodontitis, temporomandibular joint osteoarthritis, Sjögren's Syndrome, oral cancer, and other oral diseases. Additionally, it outlines potential future directions for the development of MSC-EVs. This review aims to provide a comprehensive understanding of MSC-EVs in oral disease treatment and to stimulate interest in their applications for targeted drug delivery.

Non-coding RNAs in ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament (OPLL) is a kind of disease that involves a variety of factors leading to ectopic bone deposition of the spinal ligament. Although the detailed mechanism is not clear, genetic factors play important roles in the development of this disease. Noncoding RNA (ncRNA) refers to an RNA molecule that is not translated into a protein but participates in the regulation of gene expression. Functionally important types of ncRNA associated with OPLL include long noncoding RNA, microRNA, and circular RNA. We listed the differentially expressed ncRNAs in OPLL patients and normal controls to find the ncRNAs most relevant to the pathogenesis of the disease. The potential regulatory networks of ncRNA in OPLL cells were analyzed based on their most abundant signal transduction pathway data. The analysis of the highly connected ncRNAs in the regulatory network suggests that they play an important role in OPLL. These findings provide new directions for the study of OPLL pathogenesis and therapeutic targets. In this paper, we reviewed and analyzed the literature on ncRNAs in OPLL published in recent years, aiming to help doctors better understand and treat this disease.

Nanotopography Sequentially Mediates Human Mesenchymal Stem Cell-Derived Small Extracellular Vesicles for Enhancing Osteogenesis

Engineered small extracellular vesicles (sEVs) are used as tools to enhance therapeutic efficacy. However, such application of sEVs is associated with several issues, including high costs and a high risk of tumorigenesis. Nanotopography has a greater influence on bone-related cell behaviors. However, whether nanotopography specifically mediate sEV content to perform particular biological functions remains unclear. Here, we demonstrate that selective nanotopography may be used to sequentially mediate human bone mesenchymal stem cell (hBMSC) sEVs to enhance the therapeutic efficacy of hBMSCs-EVs for osteogenesis. We subjected sEVs harvested from hBMSCs cultured on polished titanium plates (Ti) or nanotopographical titanium plates (Ti4) after 7, 14, and 21 d for RNA sequencing, and we found that there was no significant difference in sEV-miRNA expression after 7 d. Differentially expressed osteogenic-related microRNAs were founded after 14 days, and KEGG analysis indicated that the main microRNAs were associated with osteogenesis-related pathways, such as TGF-beta, AMPK, and FoxO. A significant difference was found in sEV-miRNAs expression after 21 d. We loaded sEV secreted from hBMSCs cultured on Ti4 after 21 d on 3D-printed porous PEEK scaffolds with poly dopamine (PDA) and found that such scaffolds showed superior osteogenic ability after 6- and 12-weeks. Here, we demonstrate the alkali- and heat-treated nanotopography with the ability of stimulating osteogenic differentiation of hBMSC can induce the secretion of pro-osteogenesis sEV, and we also found that sEVs meditate osteogenesis through miRNA. Thus, whether nanotopography has the ability to regulate other contents of sEVs such as proteins for enhancing osteogenesis needs further research. These findings may help us use nanotopography to extract sEVs for other biomedical applications, including cancer therapy.

Therapeutic effects of mesenchymal stem cells-derived extracellular vesicles' miRNAs on retinal regeneration: a review

Extracellular vesicles (EVs), which consist of microvesicles and exosomes, are secreted from all cells to transform vital information in the form of lipids, proteins, mRNAs and small RNAs such as microRNAs (miRNAs). Many studies demonstrated that EVs' miRNAs have effects on target cells. Numerous people suffer from the blindness caused by retinal degenerations. The death of retinal neurons is irreversible and creates permanent damage to the retina. In the absence of acceptable cures for retinal degenerative diseases, stem cells and their paracrine agents including EVs have become a promising therapeutic approach. Several studies showed that the therapeutic effects of stem cells are due to the miRNAs of their EVs. Considering the effects of microRNAs in retinal cells development and function and studies which provide the possible roles of mesenchymal stem cells-derived EVs miRNA content on retinal diseases, we focused on the similarities between these two groups of miRNAs that could be helpful for promoting new therapeutic techniques for retinal degenerative diseases.

Extracellular Vehicles of Oxygen-Depleted Mesenchymal Stromal Cells: Route to Off-Shelf Cellular Therapeutics?

Cellular therapy is a promising tool of human medicine to successfully treat complex and challenging pathologies such as cardiovascular diseases or chronic inflammatory conditions. Bone marrow-derived mesenchymal stromal cells (BMSCs) are in the limelight of these efforts, initially, trying to exploit their natural properties by direct transplantation. Extensive research on the therapeutic use of BMSCs shed light on a number of key aspects of BMSC physiology including the importance of oxygen in the control of BMSC phenotype. These efforts also led to a growing number of evidence indicating that the beneficial therapeutic effects of BMSCs can be mediated by BMSC-secreted agents. Further investigations revealed that BMSC-excreted extracellular vesicles could mediate the potentially therapeutic effects of BMSCs. Here, we review our current understanding of the relationship between low oxygen conditions and the effects of BMSC-secreted extracellular vesicles focusing on the possible medical relevance of this interplay.