Repair mechanism of radiation-induced salivary gland injury by hypoxia-pretreated human urine-derived stem cell exosomes

Cellular Senescence Contributes to the Dysfunction of Tight Junctions in Submandibular Glands of Aging Mice

The current mechanism by which aging reduces salivary secretion is unknown. This study investigates the mechanism of aging-related submandibular (SMG) dysfunction and evaluates the therapeutic potential of dental pulp stem cell-derived exosomes (DPSC-exos). We found that the stimulated salivary flow rate was significantly reduced in naturally aging and D-galactose-induced aging mice (D-gal mice) compared to control mice. Acinar atrophy and periductal fibrosis in SMGs and parotid glands (PGs) were observed in naturally aging and D-gal mice, whereas sublingual glands (SLGs) had no notable alterations. We observed the accumulation of senescent cells in the SMGs, along with a decrease in claudin-3 (Cldn-3) expression and alterations in the distribution of Cldn1 and Cldn3. Additionally, after D-gal-induced senescence of SMG-C6 cells, there was a decrease in paracellular pathway permeability, reduced expression of Cldn3 and occludin, and changes in the distribution of Cldn1, 3, 4, and 7. Furthermore, injecting DPSC-exos into the SMGs of D-gal mice improved stimulated salivary flow rate, reduced acinar atrophy, and decreased SA-β-gal activity. Our study identified that increased senescence of SMGs in aging mice can cause a decrease in salivary secretion by disrupting the expression and distribution of tight junction molecules, and injection of DPSC-exos ameliorates SMG secretory dysfunction. These findings may provide new clues to novel therapeutic targets for aging-related dysfunction of SMGs.

Mechanisms Tackling Salivary Gland Diseases with Extracellular Vesicle Therapies

Extracellular vesicles (EVs) are lipid-enclosed particles released from cells, containing lipids, DNA, RNA, metabolites, and cytosolic and cell surface proteins. EVs support intercellular communication and orchestrate organogenesis by transferring bioactive molecules in between cells. Mesenchymal stem cells are known to produce EVs, which exhibit immunomodulatory and regenerative capabilities in many target organs, including the salivary glands (SGs). Since cell-based therapies still pose challenges (e.g., donor variability, limited hemocompatibility, and safety), specific EVs may constitute a therapeutic alternative for SG diseases. New EV guidelines (MISEV2023) have recently been updated and reported by our consortium to consolidate the principles of EV biology and expand the boundaries toward innovative therapies. These guidelines provide valuable guidance for researchers to consistently assess the effectiveness of mesenchymal stem cell-derived EV cargo cues, such as microRNA, proteins, and other molecules, to target SG diseases. This review provides a narrative synthesis of preclinical studies on EVs by highlighting EV mechanisms and their potential therapeutic applications for SG diseases, such as radiotherapy-induced SG hypofunction and Sjögren's syndrome, as well as inflammatory and aging-related SG conditions. Additionally, we highlight key areas of the MISEV2023 guidelines that will support future EV-based therapies in SG research. This review adhered to PRESS guidelines (Peer Review of Electronic Search Strategies) and utilized established databases, including Medline/PubMed, Embase, Web of Science, and Scopus, alongside machine learning tools for sorting the most impactful EV studies for SG diseases.

Exosomes in Oral Diseases: Mechanisms and Therapeutic Applications

Exosomes, small extracellular vesicles secreted by various cells, play crucial roles in the pathogenesis and treatment of oral diseases. Recent studies have highlighted their involvement in orthodontics, periodontitis, oral squamous cell carcinoma (OSCC), and hand, foot, and mouth disease (HFMD). Exosomes have a positive effect on the inflammatory environment of the oral cavity, remodeling and regeneration of oral tissues, and offer promising therapeutic options for bone and periodontal tissue restoration. In OSCC tumor-derived exosomes promote cancer progression through cell proliferation, migration, invasion, and angiogenesis, and serve as potential biomarkers for early diagnosis and prognosis. Additionally, engineered exosomes constructed specifically based on exosome properties hold great promise for targeted drug delivery and regenerative therapies such as bone regeneration in orthodontics and periodontal healing. With continued research, exosomes hold great potential for improving diagnosis and treatment in oral diseases, advancing personalized and regenerative therapies.

A review of the roles of exosomes in salivary gland diseases with an emphasis on primary Sjögren's syndrome

Salivary gland diseases encompass a broad range of conditions, including autoimmune, inflammatory, obstructive, and neoplastic disorders, significantly impacting oral health and overall well-being. Recent research has highlighted the crucial role of exosomes, small extracellular vesicles, in these diseases. Exosomes mediate intercellular communication by transferring bioactive molecules such as proteins, microRNAs, and lipids, positioning them as potential diagnostic biomarkers and therapeutic agents. In primary Sjögren's syndrome (pSS), exosomes derived from Epstein-Barr virus-infected B cells and activated T cells transfer key microRNAs that impair calcium signaling, contributing to glandular dysfunction. Exosome-based biomarkers like Ro/SSA and La/SSB, found in saliva, serum, and tears, offer non-invasive diagnostic tools for early disease detection. Furthermore, mesenchymal stem cell-derived exosomes show promise in treating pSS by modulating immune responses and promoting tissue repair. While exosomes hold promise for the diagnosis and treatment of other salivary gland diseases, such as radiation-induced xerostomia and sialolithiasis, their application remains limited, necessitating further research to unlock their full diagnostic and therapeutic potential. This review focuses on the role of exosomes in salivary gland diseases, with an emphasis on pSS, and highlights the need for future clinical applications and large-scale trials.

Challenges of therapeutic applications and regenerative capacities of urine based stem cells in oral, and maxillofacial reconstruction

Urine-derived stem cells (USCs) have gained the attention of researchers in the biomedical field in the past few years . Regarding the several varieties of cells that have been used for this purpose, USCs have demonstrated mesenchymal stem cell-like properties, such as differentiation and immunomodulation. Furthermore, they could be differentiated into several lineages. This is very interesting for regenerative techniques based on cell therapy. This review will embark on describing their separation, and profiling. We will specifically describe the USCs characteristics, in addition to their differentiation potential. Then, we will introduce and explore the primary uses of USCs. These involve thier utilization as a platform to produce stem cells, however, we shall concentrate on the utilization of USCs for therapeutic, and regenerative orofacial applications, providing an in-depth evaluation of this purpose. The final portion will address the limitations and challenges of their implementation in regenerative dentistry.

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.