ALPL regulates pro-angiogenic capacity of mesenchymal stem cells through ATP-P2X7 axis controlled exosomes secretion.

BACKGROUND: Early-onset bone dysplasia is a common manifestation of hypophosphatasia (HPP), an autosomal inherited disease caused by ALPL mutation. ALPL ablation induces prototypical premature bone ageing characteristics, resulting in impaired osteogenic differentiation capacity of human bone marrow mesenchymal stem cells (hBMMSCs). As angiogenesis is tightly coupled with osteogenesis, it also plays a necessary role in sustaining bone homeostasis. We have previously observed a decrease in expression of angiogenesis marker gene CD31 in the metaphysis of long bone in Alpl+/- mice. However, the role of ALPL in regulation of angiogenesis in bone has remained largely unknown. METHODS: Exosomes derived from Normal and HPP hBMMSCs were isolated and identified by ultracentrifugation, transmission electron microscopy, and nanoparticle size measurement. The effects of ALPL on the angiogenic capacity of hBMMSCs from HPP patients were assessed by immunofluorescence, tube formation, wound healing and migration assay. exo-ELISA and Western Blot were used to evaluate the exosomes secretion of hBMMSCs from HPP, and the protein expression of VEGF, PDGFBB, Angiostatin and Endostatin in exosomes respectively. RESULTS: We verified that ALPL ablation resulted in impaired pro-angiogenic capacity of hBMMSCs, accounting for reduced migration and tube formation of human umbilical vein endothelial cells, as the quantities and proteins composition of exosomes varied with ALPL expression. Mechanistically, loss of function of ALPL enhanced ATP release. Additional ATP, in turn, led to markedly elevated level of ATP receptor P2X7, which consequently promoted exosomes secretion, resulting in a decreased capacity to promote angiogenesis. Conversely, inhibition of P2X7 increased the angiogenic induction capacity by preventing excessive release of anti-angiogenic exosomes in ALPL deficient-hBMMSCs. CONCLUSION: The ALPL-ATP axis regulates the pro-angiogenic ability of hBMMSCs by controlling exosomes secretion through the P2X7 receptor. Thus, P2X7 may be proved as an effective therapeutic target for accelerating neovascularization in ALPL-deficient bone defects.

Cinepazide maleate promotes recovery from spinal cord injury by inhibiting inflammation and prolonging neuronal survival.

This study aimed to investigate the therapeutic effects of cinepazide maleate (CM) on spinal cord injury (SCI) in rats, thereby providing an experimental basis for the use of CM as a preventative and therapeutic strategy for SCI. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining and western blot analysis were used to assess neural cell apoptosis. enzyme-linked immunosorbent assay was used to analyze the expression of interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α (TNF-α) in spinal cord tissues and cerebrospinal fluid. CD68 staining and western blot analysis were used to investigate the effect of CM on microglia activation. The effects of CM on motor function and histological damage in rats after SCI were investigated using the Basso-Beattie-Bresnahan (BBB) score, footprint assay, hematoxylin and eosin staining, and NeuN staining. In vitro models of neuronal cell injury and microglial inflammation were developed to investigate the effects of CM on apoptosis and inflammation. Functional tests (BBB score and footprint test) revealed that CM-treated rats had significantly improved motor function. In vivo CM treatment reduced the number of apoptotic cells at the site of injury. Similarly, in vitro CM treatment reduced H2 O2 -induced neuronal apoptosis. In vivo CM treatment reduced the number of CD68-positive microglia and the expression levels of TNF-α, IL-1ß, and IL-6. Similarly, in vitro CM treatment reduced LPS-induced pro-inflammatory cytokines in microglia. CM promotes the recovery of motor function by inhibiting SCI-induced apoptosis and inflammatory responses and reducing the area of the post-SCI cavity in rats. These findings indicate that CM is a potential drug worthy of translational studies for SCI treatment.

Nanorepairers Rescue Inflammation-Induced Mitochondrial Dysfunction in Mesenchymal Stem Cells.

Mitochondrial dysfunction in tissue-specific mesenchymal stem cells (MSCs) plays a critical role in cell fate and the morbidity of chronic inflammation-associated bone diseases, such as periodontitis and osteoarthritis. However, there is still no effective method to cure chronic inflammation-associated bone diseases by physiologically restoring the function of mitochondria and MSCs. Herein, it is first found that chronic inflammation leads to excess Ca2+ transfer from the endoplasmic reticulum to mitochondria, which causes mitochondrial calcium overload and further damage to mitochondria. Furthermore, damaged mitochondria continuously accumulate in MSCs due to the inhibition of mitophagy by activating the Wnt/ß-catenin pathway under chronic inflammatory conditions, impairing the differentiation of MSCs. Based on the mechanistic discovery, intracellular microenvironment (esterase and low pH)-responsive nanoparticles are fabricated to capture Ca2+ around mitochondria in MSCs to regulate MSC mitochondrial calcium flux against mitochondrial dysfunction. Furthermore, the same nanoparticles are able to deliver siRNA to MSCs to inhibit the Wnt/ß-catenin pathway and regulate mitophagy of the originally dysfunctional mitochondria. These precision-engineered nanoparticles, referred to as "nanorepairers," physiologically restore the function of mitochondria and MSCs, resulting in effective therapy for periodontitis and osteoarthritis. The concept can potentially be expanded to the treatment of other diseases via mitochondrial quality control intervention.

Giant cell tumor stromal cells: osteoblast lineage-derived cells secrete IL-6 and IL-10 for M2 macrophages polarization.

BACKGROUND: The giant cell tumor (GCT) is a benign tumor which consists of three types cells: mononuclear histiocytic cells (MNHCs), multinuclear giant cells (MNGCs), and GCT stromal cells (GCTSCs). Numerous studies claim that GCTSCs have mesenchymal stem cells (MSCs) characters and play an important role in osteoclastogenesis; however, there are no research studies concerning macrophage polarization among GCT, which can be regarded as an ingredient for tumor aggression. METHOD: We tested the effect of GCTSCs from three GCT samples which were collected from patients on proliferation, apoptosis and polarization of macrophage. RESULT: In this article, we verified that GCTSCs expressed MSCs markers and had higher proliferation and relative lower differentiation abilities compared with BMMSCs. What's more, we found a higher proportion of M2 macrophages among neoplasm. Co-culturing GCTSCs with macrophages resulted in prominent macrophage M2 polarization and increased the release of IL-6 (Interleukin-6) and IL-10 (Interleukin-10)from GCTSCs. In conclusion, GCTSCs, as originating from MSCs, can secret IL-6 and IL-10, which may play a significant role in macrophage M2 polarization.

Exosomes released from educated mesenchymal stem cells accelerate cutaneous wound healing via promoting angiogenesis.

OBJECTIVES: Skin serves as the major interface between the external environment and body which is liable to many kinds of injuries. Mesenchymal stem cell (MSC) therapy has been widely used and became a promising strategy. Pre-treatment with chemical agents, hypoxia or gene modifications can partially protect MSCs against injury, and the pre-treated MSCs show the improved differentiation, homing capacity, survival and paracrine effects regard to attenuating injury. The aim of this study was to investigate whether the exosomes from the educated MSCs contribute to accelerate wound healing process. MATERIALS AND METHODS: We extracted the exosomes from the two educated MSCs and utilized them in the cutaneous wound healing model. The pro-angiogenetic effect of exosomes on endothelial cells was also investigated. RESULTS: We firstly found that MSCs pre-treated by exosomes from neonatal serum significantly improved their biological functions and the effect of therapy. Moreover, we extracted the exosomes from the educated MSCs and utilized them to treat the cutaneous wound model directly. We found that the released exosomes from MSCs which educated by neonatal serum before had the more outstanding performance in therapeutic effect. Mechanistically, we revealed that the recipient endothelial cells (ECs) were targeted and the exosomes promoted their functions to enhance angiogenesis via regulating AKT/eNOS pathway. CONCLUSIONS: Our findings unravelled the positive effect of the upgraded exosomes from the educated MSCs as a promising cell-free therapeutic strategy for cutaneous wound healing.