Exosomes from Cyclic Stretched Periodontal Ligament Cells Induced Periodontal Inflammation through miR-9-5p/SIRT1/NF-κB Signaling Pathway

The science of exosomes: Understanding their formation, capture, and role in cellular communication

Extracellular vesicles (EVs) serve as a crucial method for transferring information among cells, which is vital in multicellular organisms. Among these vesicles, exosomes are notable for their small size, ranging from 20 to 150 nm, and their role in cell-to-cell communication. They carry lipids, proteins, and nucleic acids between cells. The creation of exosomes begins with the inward budding of the cell membrane, which then encapsulates various macromolecules as cargo. Once filled, exosomes are released into the extracellular space and taken up by target cells via endocytosis and similar processes. The composition of exosomal cargo varies, encompassing diverse macromolecules with specific functions. Because of their significant roles, exosomes have been isolated from various cell types, including cancer cells, endothelial cells, macrophages, and mesenchymal cells, with the aim of harnessing them for therapeutic applications. Exosomes influence cellular metabolism, and regulate lipid, glucose, and glutamine pathways. Their role in pathogenesis is determined by their cargo, which can manipulate processes such as apoptosis, proliferation, inflammation, migration, and other molecular pathways in recipient cells. Non-coding RNA transcripts, a common type of cargo, play a pivotal role in regulating disease progression. Exosomes are implicated in numerous biological and pathological processes, including inflammation, cancer, cardiovascular diseases, diabetes, wound healing, and ischemic-reperfusion injury. As a result, they hold significant potential in the treatment of both cancerous and non-cancerous conditions.

miR-345-3p Modulates M1/M2 Macrophage Polarization to Inhibit Inflammation in Bone Infection via Targeting MAP3K1 and NF-κB Pathway

Infection after fracture fixation (IAFF), a complex infectious disease, causes inflammatory destruction of bone tissue and poses a significant clinical challenge. miR-345-3p is a biomarker for tibial infected nonunion; however, the comprehensive mechanistic role of miR-345-3p in IAFF is elusive. In this study, we investigated the role of miR-345-3p in IAFF pathogenesis through in vivo and in vitro experiments. In vivo, in a rat model of IAFF, miR-345-3p expression was downregulated, accompanied by increased M1 macrophage infiltration and secretion of proinflammatory factors. In vitro, LPS induced differentiation of primary rat bone marrow-derived macrophages into M1 macrophages, which was attenuated by miR-345-3p mimics. miR-345-3p promoted M1 to M2 macrophage transition-it reduced the expression of cluster of differentiation (CD) 86, inducible NO synthase, IL-1β, and TNF-α but elevated those of CD163, arginase-1, IL-4, and IL-10. MAPK kinase kinase 1 (MAP3K1), a target mRNA of miR-345-3p, was overexpressed in the bone tissue of IAFF rats compared with that in those of the control rats. The M1 to M2 polarization inhibited MAP3K1 signaling pathways in vitro. Conversely, MAP3K1 overexpression promoted the transition from M2 to M1. miR-345-3p significantly inhibited NF-κB translocation from the cytosol to the nucleus in a MAP3K1-dependent manner. In conclusion, miR-345-3p promotes the polarization of M1 macrophages to the M2 phenotype by inhibiting the MAP3K1 and NF-κB pathways. These findings provide insight into the pathogenesis and immunotherapeutic strategies for IAFF and offer potential new targets for subsequent research.

Emerging roles of exosomes in oral diseases progression

Oral diseases, such as periodontitis, salivary gland diseases, and oral cancers, significantly challenge health conditions due to their detrimental effects on patient's digestive functions, pronunciation, and esthetic demands. Delayed diagnosis and non-targeted treatment profoundly influence patients' prognosis and quality of life. The exploration of innovative approaches for early detection and precise treatment represents a promising frontier in oral medicine. Exosomes, which are characterized as nanometer-sized extracellular vesicles, are secreted by virtually all types of cells. As the research continues, the complex roles of these intracellular-derived extracellular vesicles in biological processes have gradually unfolded. Exosomes have attracted attention as valuable diagnostic and therapeutic tools for their ability to transfer abundant biological cargos and their intricate involvement in multiple cellular functions. In this review, we provide an overview of the recent applications of exosomes within the field of oral diseases, focusing on inflammation-related bone diseases and oral squamous cell carcinomas. We characterize the exosome alterations and demonstrate their potential applications as biomarkers for early diagnosis, highlighting their roles as indicators in multiple oral diseases. We also summarize the promising applications of exosomes in targeted therapy and proposed future directions for the use of exosomes in clinical treatment.

Cyclic stretch-induced exosomes from periodontal ligament cells promote osteoblasts osteogenic differentiation via the miR-181d-5p/TNF signaling pathway

OBJECTIVE

To investigate the effects of cyclic stretch-induced periodontal ligament cell (PDLC) exosomes on osteoblast differentiation, and to explore their regulatory role in mechanical force-related periodontal tissue remodeling.

DESIGN

After applying 20 % cyclic stretch loading to PDLCs, exosomes were extracted from the supernatant and co-cultured with osteoblasts to detect their effects on osteogenic differentiation. Meanwhile, the exosomes were sequenced by high-throughput microRNA sequencing for bioinformatic analysis and validation to explore exosome signaling pathways through miRNAs.

RESULTS

Cyclic stretch-induced PDLC exosomes could be taken up by osteoblasts and promoted osteogenic differentiation of osteoblasts, as demonstrated by the increased expression levels of osteogenesis-related factors and enhanced alkaline phosphatase (Alp) staining. Among the differentially expressed miRNAs between exosomes from cyclic stretch group and control group, miRNA-181d-5p was up-regulated significantly. The expression levels of osteogenesis-related factors and Alp staining were also increased in osteoblasts transfected with miR-181d-5p, and this effect might be related to the inhibitory role of exosomal miR-181d-5p on tumor necrosis factor (TNF).

CONCLUSIONS

Cyclic stretch-induced PDLC exosomes exhibited a promoting effect on osteogenic differentiation, which might result from the inhibition of TNF via exosomal miR-181d-5p.