isolation-therapeutic-application-extracellular-vesicles-derived-from

Isolation and Therapeutic Application of Extracellular Vesicles Derived from Self-Assembled Mesenchymal Stem Cell Aggregates

Extracellular vesicles (EVs) are vital mediators of intercellular communication and promising cell-free agents for regenerative medicine. Among EV ...

The Fourth Military Medical University

Type H vessels couple angiogenesis with osteogenesis, while sympathetic cues regulate vascular and skeletal function. The crosstalk between sympathetic nerves and type H vessels in bone remains unclear. Here, we first identify close spatial connections between sympathetic nerves and type H vessels in bone, particularly in metaphysis. Sympathoexcitation, mimicked by isoproterenol (ISO) injection, reduces type H vessels and bone mass. Conversely, beta-2-adrenergic receptor (ADRB2) deficiency maintains type H vessels and bone mass in the physiological condition.  experiments reveal indirect sympathetic modulation of angiogenesis via paracrine effects of mesenchymal stem cells (MSCs), which alter the transcription of multiple angiogenic genes in endothelial cells (ECs). Furthermore, Notch signaling in ECs underlies sympathoexcitation-regulated type H vessel formation, impacting osteogenesis and bone mass. Finally, propranolol (PRO) inhibits beta-adrenergic activity and protects type H vessels and bone mass against estrogen deficiency. These findings unravel the specialized neurovascular coupling in bone homeostasis and regeneration.

Region-specific sympatho-adrenergic regulation of specialized vasculature in bone homeostasis and regeneration.

Breast cancer, the most prevalent malignancy in women, often progresses to bone metastases, especially in older individuals. Dormancy, a critical aspect of bone-metastasized breast cancer cells (BCCs), enables them to evade treatment and recur. This dormant state is regulated by bone marrow mesenchymal stem cells (BMMSCs) through the secretion of various factors, including those associated with senescence. However, the specific mechanisms by which BMMSCs induce dormancy in BCCs remain unclear. To address this gap, a bone-specific senescence-accelerated murine model, SAMP6, was utilized to minimize confounding systemic age-related factors. Confirming senescence-accelerated osteoporosis, distinct BMMSC phenotypes were observed in SAMP6 mice compared to SAMR1 counterparts. Notably, SAMP6-BMMSCs exhibited premature senescence primarily due to telomerase activity loss and activation of the p21 signaling pathway. Furthermore, the effects of conditioned medium (CM) derived from SAMP6-BMMSCs versus SAMR1-BMMSCs on BCC proliferation were examined. Intriguingly, only CM from SAMP6-BMMSCs inhibited BCC proliferation by upregulating p21 expression in both MCF-7 and MDA-MB-231 cells. These findings suggest that the senescence-associated secretory phenotype (SASP) of BMMSCs suppresses BCC viability by inducing p21, a pivotal cell cycle inhibitor and tumor suppressor. This highlights a heightened susceptibility of BCCs to dormancy in a senescent microenvironment, potentially contributing to the increased incidence of breast cancer bone metastasis and recurrence observed with aging.

A Senescence-Associated Secretory Phenotype of Bone Marrow Mesenchymal Stem Cells Inhibits the Viability of Breast Cancer Cells.

Periodontal disease is a major contributor to tooth loss worldwide in adults. Particularly, periodontal bone defect is a common clinical condition, yet current therapeutic strategies exhibit limited effectiveness. Recently, natural bone graft materials have attracted considerable interest for enhancing bone defect repair due to their superior biocompatibility and osteogenic capabilities. Nevertheless, clinically applicable human-derived biomaterials to boost bone regeneration are currently not accessible. Here, enlightened by the decellularization technique, we successfully prepared the human decellularized alveolar bone and tooth dentin tissues from healthy individuals and obtained micro-sized bioactive decellularized extracellular matrix (dECM) particles for treatment of periodontal bone defects. After characterizing the two representative dECM tissues and particles by multiple physiochemical approaches, we revealed that both human decellularized alveolar bone matrix particles (hDABMPs) and human decellularized tooth dentin matrix particles (hDTDMPs) possessed excellent biocompatibility. Furthermore, both biomaterials significantly enhanced the proliferation and osteogenic differentiation of human dental follicle stem cells, potentially contributing to periodontal bone formation. Indeed, in a rat model, both types of dECM microparticles were found to facilitate tissue regeneration at periodontal bone defect sites, demonstrating comparable efficacy for promoting bone defect repair. Collectively, this study provides an important basis for clinical exploration of natural human-derived micro-sized biomaterials for periodontal bone defect repair and opens a new path for periodontal disease treatment strategies.

Optimizing natural human-derived decellularized tissue materials for periodontal bone defect repair.

Psychological stress has been associated with the onset of several diseases, including osteoporosis. However, the underlying pathogenic mechanism remains unknown, and effective therapeutic strategies are still unavailable. Growing evidence suggests that the sympathetic nervous system regulates bone homeostasis and vascular function under psychological stress, as well as the coupling of osteogenesis and angiogenesis in bone development, remodeling, and regeneration. Furthermore, extracellular vesicles (EVs), particularly mesenchymal stem cell extracellular vesicles (MSC-EVs), have emerged as prospecting therapies for stimulating angiogenesis and bone regeneration. We summarize the role of sympathetic regulation in bone homeostasis and vascular function in response to psychological stress and emphasize the relationship between vessels and bone. Finally, we suggest using MSC-EVs as a promising therapeutic method for treating osteoporosis in psychological stress.

Osteoporosis under psychological stress: mechanisms and therapeutics.

Periodontitis is a prevalent and progressive detrimental disease characterized by chronic inflammation, and the immunopathological mechanisms are not yet fully understood. Mesenchymal stem cells (MSCs) play crucial roles as immunoregulators and maintain tissue homeostasis and regeneration, but their in vivo function in immunopathology and periodontal tissue deterioration is still unclear. Here, we utilized multiple transgenic mouse models to specifically mark, ablate and modulate Gli1 cells, a critical and representative subset of MSCs in the periodontium, to explore their specific role in periodontal immunopathology. We revealed that Gli1 cells, upon challenge with an inflammatory microenvironment, significantly induce rapid trafficking and aberrant activation of neutrophils, thus exacerbating alveolar bone destruction. Mechanistically, extracellular vesicles (EVs) released by Gli1 cells act as crucial immune regulators in periodontal tissue, mediating the recruitment and activation of neutrophils through increased neutrophil generation of reactive oxygen species and stimulation of nuclear factor kappa-B signaling. Furthermore, we discovered that CXC motif chemokine ligand 1 (CXCL1) is exposed on the surface of EVs derived from inflammation-challenged Gli1 cells to prime aberrant neutrophils via the CXCL1-CXC motif chemokine receptor 2 (CXCR2) axis. Importantly, specific inhibition of EV release from Gli1 cells or pharmacological therapy with GANT61 ameliorates periodontal inflammation and alveolar bone loss. Collectively, our findings identify previously unrecognized roles of Gli1 cells in orchestrating infiltration and promoting aberrant activation of neutrophils under inflammation, which provides pathological insights and potential therapeutic targets for periodontitis.

Inflammation-triggered Gli1 stem cells engage with extracellular vesicles to prime aberrant neutrophils to exacerbate periodontal immunopathology.

Harnessing natural developmental programs to repair and replace damaged organs represents promising approaches in regenerative medicine. However, effective strategies are still lacking for tissue regeneration in complicated conditions, such as the periodontal bone defect. Here, human dental follicle stem cells (hDFSCs) and their aggregates (hDFSCA) are cultured and characterized, which are formed based on the inherent property of these stem cells self-assembly into compact spheroid-like structures, mimicking mesenchymal condensation in development. A periodontal tissue-specific microenvironment simulation material is then established, human decellularized alveolar bone matrix particles (hDABMPs), which possess favorable physicochemical and biological properties for regenerative use. hDFSCs co-cultured with hDABMPs exhibit improved cell function, and hDFSCA-hDABMP co-aggregates are subsequently constructed, which activate the developmental gene expression in hDFSCA and initiate hypoxic adaptation mechanisms for tissue regeneration. Indeed, hDFSCA-hDABMP co-aggregates significantly promote regeneration after implantation in alveolar bone defects with good biosafety. Interestingly, during the early stages of implantation, hDABMPs enhance hDFSC survival and expansion, thereby providing a sufficient source of cells for tissue regeneration. Collectively, this study reveals a development-inspired, engineered cell-niche co-aggregation strategy for enhancing CA therapeutic potential by simulating tissue-specific microenvironments, offering novel insights for functional tissue regeneration.

Development-Inspired Biomimetic Cell-Niche Coaggregates Safeguard Tooth Stem Cell-Based Functional Tissue Regeneration.

Ferroptosis, a form of regulated cell death driven by iron accumulation and lipid peroxidation, is implicated in various diseases, but effective therapeutic strategies remain limited. Lysosomal impairments cause iron dysregulation and initiate ferroptosis, which potentially contribute to ionizing radiation-induced tissue damages. Here, the role of intercellular lysosomal regulation in governing iron homeostasis and protecting against ferroptosis is investigated in models of stem cell aggregation and mandibular regeneration post-irradiation. Lysosomes are discovered to accumulate in specific regions within multi-stem cell aggregates and regulate cell aggregate formation based on iron control, which is occurred through hypoxic signaling-driven lysosomal redistribution mediated by extracellular vesicles. These vesicles exhibit lysosomal features and possess iron-regulating properties, which rescue lysosomal defects to restore iron homeostasis and mitigate ferroptosis in recipient endothelial cells against the irradiation challenge. Based on lysosomal regulation and anti-ferroptosis, these cell aggregate-released extracellular vesicles (CA-EVs) stimulate the growth of CD31endomucin specialized vessels despite irradiation both in vitro and in vivo, which further promote bone regeneration of post-irradiation mandibular defect. These findings highlight the potential of taking CA-EVs as natural therapeutic agents to safeguard lysosomal function, modulate iron metabolism, and protect against ferroptosis, paving an avenue for combating post-irradiation endothelial injuries and enhancing tissue regeneration.

Lysosome-Featured Cell Aggregate-Released Extracellular Vesicles Regulate Iron Homeostasis and Alleviate Post-Irradiation Endothelial Ferroptosis for Mandibular Regeneration.

The reduced angiogenesis in diabetes mellitus (DM) represents a critical barrier to effective skin wound healing. Therapeutic strategies involving mesenchymal stem cells (MSCs) and MSC-derived exosomes (EXOs) have demonstrated potential in promoting wound healing in diabetic contexts. However, each approach presents specific limitations.

Article	Year
Region-specific sympatho-adrenergic regulation of specialized vasculature in bone homeostasis and regeneration. iScience\| PubMed ID: 37680481	2023
A Senescence-Associated Secretory Phenotype of Bone Marrow Mesenchymal Stem Cells Inhibits the Viability of Breast Cancer Cells. Stem cell reviews and reports\| PubMed ID: 38457059	2024
Optimizing natural human-derived decellularized tissue materials for periodontal bone defect repair. Biochemical and biophysical research communications\| PubMed ID: 39818190	2025
Osteoporosis under psychological stress: mechanisms and therapeutics. Life medicine\| PubMed ID: 39872391	2024
Inflammation-triggered Gli1 stem cells engage with extracellular vesicles to prime aberrant neutrophils to exacerbate periodontal immunopathology. Cellular & molecular immunology\| PubMed ID: 40016585	2025
Development-Inspired Biomimetic Cell-Niche Coaggregates Safeguard Tooth Stem Cell-Based Functional Tissue Regeneration. Advanced healthcare materials\| PubMed ID: 40376872	2025
Lysosome-Featured Cell Aggregate-Released Extracellular Vesicles Regulate Iron Homeostasis and Alleviate Post-Irradiation Endothelial Ferroptosis for Mandibular Regeneration. Advanced science (Weinheim, Baden-Wurttemberg, Germany)\| PubMed ID: 40546115	2025
Endothelial cell-targeting aptamer-empowered exosomes accelerate wound healing by promoting specialized angiogenesis in type 1 diabetic mice. Stem cell research & therapy\| PubMed ID: 41354930	2025

Hao-Kun Xu

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