Canine osteosarcoma (OSA) is the most common cancer of the appendicular skeleton and is associated with high metastatic rate to the lungs and poor prognosis. Recent studies have shown the impact of ...malignant-derived exosomes on immune cells and the facilitation of immune evasion. In the current study, we have characterized the proteomic profile of exosomes derived from healthy osteoblasts and osteosarcoma cell lines. We investigated the direct impact of these exosomes on healthy T cells.
Proteomic cargo of the malignant exosomes was markedly different from osteoblastic exosomes and contained immunosuppressive proteins including TGF-β, α fetoprotein and heat shock proteins. OSA exosomes directly attenuated the rate of T cell proliferation, increased a regulatory (FoxP3+) CD4+ phenotype and diminished the expression of the activation marker CD25+ on CD8+ cells. Exosomes of osteoblasts also demonstrated a direct impact on T cells, but to a lesser degree.
Osteosarcoma-derived exosomes compared to normal osteoblasts contain an immunomodulatory cargo, which reduced the rate of T cell proliferation and promoted T regulatory phenotype. Osteoblast-derived exosomes can also reduce T cell activity, but to lesser degree compared to OSA exosomes and without promoting a T regulatory phenotype.
•Proteomic profiles of osteoblasts and osteosarcoma exosomes have been characterized.•Malignant exosomes have immunosuppressive phenotype.•Osteosarcoma exosomes inhibit CD4+ and CD8+ T cell proliferation and activation.•Osteosarcoma exosomes can upregulate the expression of FOXP3 and CD25+ in CD4+ T cells.
Postmenopausal osteoporosis (PMOP) is a metabolic bone disease caused by unbalance between osteoblast bone formation and osteoclast bone resorption. In this study, the moderating effect of DGCR5 on ...osteogenic differentiation and its role in PMOP was assessed.
The expression levels of DGCR5, miR-30d-5p, and Runt-related transcription factor 2 (Runx2) mRNA and protein were determined by qRT-PCR and western blot, separately. The bone marrow human mesenchymal stem cells (hMSCs) were isolated from bone marrow of patients with PMOP or the healthy control. ALP activity and bone mineral density (BMD) were detected to reflect the osteogenic differentiation status. RIP and RNA pull-down assay were performed to explore the combination and interaction between DGCR5 and miR-30d-5p.
Compared with the healthy control group (n = 20), DGCR5 was down-regulated in hMSCs from patients with PMOP (n = 20). Overexpression of DGCR5 induced osteogenic differentiation of hMSCs. DGCR5 up-regulated the expression of Runx2 through miR-30d-5p. DGCR5 up-regulated the expression of Runx2 through miR-30d-5p to induce osteogenic differentiation of hMSCs.
DGCR5 negatively regulates miR-30d-5p, and it up-regulates Runx2 through miR-30d-5p, thereby inducing osteogenic differentiation of hMSCs, which may help to delay PMOP development.
Osteoporosis is a global public health concern and, it can result from numerous pathogenic mechanisms, many of which are closely related with age, nutritional disorders, endocrine imbalance, or ...adverse drug side effects presented by glucocorticoids, heparin, and anti-epileptics. Given its wide range etiologies, it is crucial to establish an animal model of osteoporosis for use in screening potential drugs quickly and effectively. Previous research has reported that an accumulation of elevated iron in the body is an independent risk factor for osteoporosis. As such, we sought to use both zebrafish larvae and adults to model an osteoporosis phenotype using high iron stress (FAC, ferric ammonium citrate). Skeletal staining results suggested that iron-overload caused a significant decrease in bone calcification as well as severe developmental cartilage defects. In addition, osteoblast and cartilage-specific mRNA expression levels were downregulated after exposure to a high-iron environment. Most importantly, we demonstrated in both larval and adult fish that high iron-induced osteogenic defects were significantly rescued using alendronate (AL), a drug known to be effective against to human osteoporosis. Even more, the repair effect of AL was achieved by facilitating osteoblast differentiation and targeting Bmp signaling. Taken together, our findings propose an rapid and effective osteoporosis model, which could be used widely for future osteoporosis drug screening.
•Establish a rapid and robust zebrafish model of osteoporosis using high iron stress.•High iron-overloaded results in severe defects in skeletal development.•High iron stress leads significant downregulation of osteoblast-specific mRNAs.•This osteoporosis phenotype is effectively repaired by a known drug Alendronate (AL).•AL could rescue osteoporosis larval fish through facilitating osteoblast differentiation.
The Mexican Axolotl is one of the few tetrapod species that is capable of regenerating complete skeletal elements in injured adult limbs. Whether the skeleton (bone and cartilage) plays a role in the ...patterning and contribution to the skeletal regenerate is currently unresolved. We tested the induction of pattern formation, the effect on cell proliferation, and contributions of skeletal tissues (cartilage, bone, and periosteum) to the regenerating axolotl limb. We found that bone tissue grafts from transgenic donors expressing GFP fail to induce pattern formation and do not contribute to the newly regenerated skeleton. Periosteum tissue grafts, on the other hand, have both of these activities. These observations reveal that skeletal tissue does not contribute to the regeneration of skeletal elements; rather, these structures are patterned by and derived from cells of non-skeletal connective tissue origin.
Display omitted
•Periosteum induces the formation of ectopic limb structures.•Skeletal grafts have minimal pattern inducing activity on regenerating limbs.•Heparin-sulfate chains are required for inductive activity of periosteum.•Periosteum contributes to the regenerated skeletal elements.•Skeletal tissue does not contribute to the regenerate.
Pericytes are multipotent cells present in every vascularized tissue in the body. Despite the fact that they are well-known for more than a century, pericytes are still representing cells with ...intriguing properties. This is mainly because of their heterogeneity in terms of definition, tissue distribution, origin, phenotype and multi-functional properties. The body of knowledge illustrates importance of pericytes in the regulation of homeostatic and healing processes in the body.
In this review, we summarized current knowledge regarding identification, isolation, ontogeny and functional characteristics of pericytes and described molecular mechanisms involved in the crosstalk between pericytes and endothelial or immune cells. We highlighted the role of pericytes in the pathogenesis of fibrosis, diabetes-related complications (retinopathy, nephropathy, neuropathy and erectile dysfunction), ischemic organ failure, pulmonary hypertension, Alzheimer disease, tumor growth and metastasis with the focus on their therapeutic potential in the regenerative medicine. The functions and capabilities of pericytes are impressive and, as yet, incompletely understood. Molecular mechanisms responsible for pericyte-mediated regulation of vascular stability, angiogenesis and blood flow are well described while their regenerative and immunomodulatory characteristics are still not completely revealed. Strong evidence for pericytes' participation in physiological, as well as in pathological conditions reveals a broad potential for their therapeutic use. Recently published results obtained in animal studies showed that transplantation of pericytes could positively influence the healing of bone, muscle and skin and could support revascularization. However, the differences in their phenotype and function as well as the lack of standardized procedure for their isolation and characterization limit their use in clinical trials.
Critical to further progress in clinical application of pericytes will be identification of tissue specific pericyte phenotype and function, validation and standardization of the procedure for their isolation that will enable establishment of precise clinical settings in which pericyte-based therapy will be efficiently applied.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The aim of this study was to provide an overview on the biology and soft tissue sealing around dental implants and teeth.
This is a narrative review performed through scientific articles published ...between 1977 and 2014, indexed in MEDLINE and PubMed databases. The study selected articles that focused on epithelial sealing around dental implant or teeth with cell biology and histology of soft tissue.
Implant therapy has been widely applied in dental rehabilitation for many years, with predictable long-term results. The longevity and functionality of dental implants is dependent on both osseointegration around the implant body and the establishment of a soft tissue barrier that protects the underlying hard tissue structures and the implant itself. The health and stability of the peri-implant mucosa also affects the esthetics of the implant. The healing and maintenance of the epithelial and connective tissues around implants are increasingly recognized as being fundamental to implant success. However, there has been little research into the function or formation of the soft tissue seal around dental implants, and the roles of this unique mucosal interface remain unclear.
This narrative review explores the extent of the current knowledge of soft tissue barriers around implants from both a basic and clinical perspective, and aims to consolidate this knowledge and highlight the most pertinent questions relating to this area of research.
•BMP2/DLX3 pathway supports osteogenic differentiation of dental follicle cells (DFCs).•NOTCH signaling is induced by DLX3 and during the osteogenic differentiation of DFCs.•NOTCH signaling impairs ...the osteogenic differentiation and the expression of DLX3.•A BMP2/DLX3/NOTCH feedback loop regulates the osteogenic differentiation of DFCs.
Dental follicle cells (DFCs) are dental stem/progenitor cells and the genuine precursors of alveolar osteoblasts and dental cementoblasts. A previous study showed that the transcription factor DLX3 (distal less homeobox 3) supports the osteogenic differentiation in DFCs via a positive feedback loop with the bone morghogenetic protein (BMP) 2. Until today, however, the control of this BMP2/DLX3 pathway by additional signaling pathways remains elusive. Previous studies also suggested that the NOTCH signaling pathway plays a role in the osteogenic differentiation of DFCs. In this study we showed that DLX3 overexpression and the initiation of the osteogenic differentiation by BMP2 or dexamethasone induced the NOTCH signaling pathway in DFCs. However, the induction of NOTCH-signaling impaired not only the osteogenic differentiation (ALP activity and mineralized nodules) but also the expression of the transcription factor DLX3 and the activation of the BMP-signaling pathway. So, NOTCH signaling plays a regulatory role for the osteogenic differentiation of DFCs. In conclusion, results of our study suggest that the NOTCH-signaling pathway, which is activated during the osteogenic differentiation of DFCs, regulates the BMP2/DLX3 directed differentiation of DFCs via a negative feed-back loop.
The age-related reduction in the function of osteoblasts plays a central role in the pathogenesis of bone loss and osteoporosis. Collagen synthesis is a primary function of differentiated ...osteoblasts, however, the mechanisms for age-related changes in collagen synthesis in human osteoblasts remain elusive.
We use Gene Ontology (GO) analysis and Gene Set Enrichment Analysis (GSEA) analysis to exploit the transcriptional profiles of osteoblasts from young and old donors. A panel of collagen members was downregulated in aged osteoblasts, including COL12A1, COL5A1, COL5A3, COL8A1 and COL8A2. Co-expression analysis followed by GO analysis revealed that oxidoreductase activity and kinase activity were inversely correlated with collagen synthesis in osteoblasts. GESA analysis further showed that JNK signaling was upregulated in aged osteoblasts. Consistently, MAP3K4 and MAP4K2, upstream of JNK, were also increased in aged osteoblasts. Moreover, expression levels of MAP3K4 were significantly inversely correlated with levels of the collagen genes. Those transcriptomic results were further verified by examining clinical specimens of osteoporosis by immunohistochemistry.
These results provide transcriptomic evidence that deregulated JNK signaling may impair collagen synthesis in osteoblasts and imply a therapeutic value of JNK inhibitors for treating osteoporosis and preventing skeletal aging by counteracting the age-related reduction in the function of osteoblasts.
•Transcription of five collagen members, e.g., COL12A1 and COL8A2, reduced significantly in the osteoblasts of old donors.•Oxidoreductase activity and kinase activity were inversely correlated with collagen expression in aged osteoblasts.•Gene expression signature of JNK signaling was enriched in aged osteoblasts.•MAP3K4 and MAP4K2 were upregulated and inversely correlated with collagen expression in aged osteoblasts.
The lineage of periodontal ligament (PDL) stem cells contributes to alveolar bone (AB) and cementum formation, which are essential for tooth-jawbone attachment. Leptin receptor (LepR), a skeletal ...stem cell marker, is expressed in PDL; however, the stem cell capacity of LepR
PDL cells remains unclear. We used a Cre/LoxP-based approach and detected LepR-cre-labeled cells in the perivascular around the root apex; their number increased with age. In the juvenile stage, LepR
PDL cells differentiated into AB-embedded osteocytes rather than cementocytes, but their contribution to both increased with age. The frequency of LepR
PDL cell-derived lineages in hard tissue was < 20% per total cells at 1-year-old. Similarly, LepR
PDL cells differentiated into osteocytes following tooth extraction, but their frequency was < 9%. Additionally, both LepR
and LepR
PDL cells demonstrated spheroid-forming capacity, which is an indicator of self-renewal. These results indicate that both LepR
and LepR
PDL populations contributed to hard tissue formation. LepR
PDL cells increased the expression of LepR during spheroid formation, suggesting that the LepR
PDL cells may hierarchically sit upstream of LepR
PDL cells. Collectively, the origin of hard tissue-forming cells in the PDL is heterogeneous, some of which express LepR.
Exosomes are nanometer-sized vesicles with the function of intercellular communication, and they are released by various cell types. To reveal the knowledge about the exosomes from osteoblast, and ...explore the potential functions of osteogenesis, we isolated microvesicles from supernatants of mouse Mc3t3 by ultracentrifugation, characterized exosomes by electron microscopy and immunoblotting and presented the protein profile by proteomic analysis. The result demonstrated that microvesicles were between 30 and 100 nm in diameter, round shape with cup-like concavity and expressed exosomal marker tumor susceptibility gene (TSG) 101 and flotillin (Flot) 1. We identified a total number of 1069 proteins among which 786 proteins overlap with ExoCarta database. Gene Oncology analysis indicated that exosomes mostly derived from plasma membrane and mainly involved in protein localization and intracellular signaling. The Ingenuity Pathway Analysis showed pathways are mostly involved in exosome biogenesis, formation, uptake and osteogenesis. Among the pathways, eukaryotic initiation factor 2 pathways played an important role in osteogenesis. Our study identified osteoblast-derived exosomes, unveiled the content of them, presented potential osteogenesis-related proteins and pathways and provided a rich proteomics data resource that will be valuable for further studies of the functions of individual proteins in bone diseases.
•We for the first time identified exosomes from mouse osteoblast.•Osteoblasts-derived exosomes contain osteoblast peculiar proteins.•Proteins from osteoblasts-derived exosomes are intently involved in EIF2 pathway.•EIF2α from the EIF2 pathway plays an important role in osteogenesis.
PDF
