a b s t r a c tElucidation of the molecular mechanisms governing human adipose-derived mesenchymal stem cells (hASCs) osteogenic differentiation is of great importance for improving the treatment of bone-related diseases. In this study, we examined the role of microRNA (miR)-100 on the osteogenesis of hASCs. Overexpression of miR-100 inhibited osteogenic differentiation of hASCs in vitro, whereas downregulation of miR-100 enhanced the process. Target prediction analysis and dual luciferase report assay confirmed that bone morphogenetic protein receptor type II (BMPR2) was a direct target of miR-100. Furthermore, knockdown of BMPR2 by RNA interference inhibited osteogenic differentiation of hASCs, similar as the effect of upregulation miR-100. Taken together, our findings imply that miR-100 plays a negative role in osteogenic differentiation and might act through targeting BMPR2.

“Warburg effect”, the enhanced glycolysis or aerobic glycolysis, confers cancer cells the ability to survive and proliferate even under stressed conditions. In this study, we explored the role of epidermal growth factor (EGF) in orchestrating Warburg effect, the epithelial-mesenchymal transition (EMT) process, and the acquisition of cancer stem-like cell properties in human oral squamous cell carcinoma (OSCC) cells. Our results showed that EGF induces EMT process in OSCC cells, which correlates with the acquisition of cancer stem-like properties, including the enrichment of CD44+/CD24− population of cancer cells and an increased expression of CSC-related genes, aldehyde dehydrogenase-1 (ALDH1) and Bmi-1. We also showed that EGF concomitantly enhanced L-lactate production, while blocking glycolysis by 2-deoxy-D-glucose (2-DG) robustly reversed EGF-induced EMT process and CSC-like properties in OSCC cells. Mechanistically, we demonstrated that EGF promoted EMT process and CSC generation through EGFR/PI3K/HIF-1α axis-orchestrated glycolysis. Using an orthotopic tumor model of human OSCC (UM-SCC1) injected in the tongue of BALB/c nude mice, we showed that treatment with 2-DG in vivo significantly inhibited the metastasis of tumor cells to the regional cervical lymph nodes and reduced the expression of ALDH1 and vimentin in both in situ tumors and tumor cell-invaded regional lymph nodes. Taken together, these findings have unveiled a new mechanism that EGF drives OSCC metastasis through induction of EMT process and CSC generation, which is driven by an enhanced glycolytic metabolic program in OSCC cells.

A unique subpopulation of mesenchymal stem cells (MSCs) has been isolated and characterized from human gingival tissues (GMSCs). Similar to MSCs derived from other sources of tissues, e.g. bone marrow, adipose or umbilical cord, GMSCs also possess multipotent differentiation capacities and potent immunomodulatory effects on both innate and adaptive immune cells through the secretion of various types of bioactive factors with immunosuppressive and anti-inflammatory functions. Uniquely, GMSCs are highly proliferative and have the propensity to differentiate into neural cell lineages due to the neural crest-origin. These properties have endowed GMSCs with potent regenerative and therapeutic potentials in various preclinical models of human disorders, particularly, some inflammatory and autoimmune diseases, skin diseases, oral and maxillofacial disorders, and peripheral nerve injuries. All types of cells release extracellular vesicles (EVs), including exosomes, that play critical roles in cell-cell communication through their cargos containing a variety of bioactive molecules, such as proteins, nucleic acids, and lipids. Like EVs released by other sources of MSCs, GMSC-derived EVs have been shown to possess similar biological functions and therapeutic effects on several preclinical diseases models as GMSCs, thus representing a promising cell-free platform for regenerative therapy. Taken together, due to the easily accessibility and less morbidity of harvesting gingival tissues as well as the potent immunomodulatory and anti-inflammatory functions, GMSCs represent a unique source of MSCs of a neural crest-origin for potential application in tissue engineering and regenerative therapy.

Diabetes mellitus is an established risk factor associated with bisphosphonate-related osteonecrosis of the jaw (BRONJ). Sustained activation of Nod-like receptor (NLR) family, pyrin domain-containing protein 3 (NLRP3) inflammasome contributes to the persistent inflammation and impaired cutaneous wound healing in diabetic mice and human. We have recently demonstrated a compelling linkage between M1 macrophages and BRONJ conditions in both murine and human diseases. The aim of this study was to determine whether NLRP3 inflammasome activation is involved in BRONJ development in diabetic mice. We showed an increased incidence of delayed oral wound healing and bone necrosis of extraction sockets in db/db mice as compared to those in non-diabetic db/+ controls, which correlated with an elevated expression of NLRP3, caspase-1 and IL-1β in macrophages residing at local wounds. Constitutively, bone marrow-derived macrophages from db/db mice (db/db BMDMs) secrete a relatively higher level of IL-1β than those from db/+ mice (db/+ BMDMs). Upon stimulation by NLRP3 activators, the secretion of IL-1β by db/db BMDMs was 1.77-fold higher than that by db/+ BMDMs (p<0.001). Systemic treatment of mice with zoledronate (Zol), a nitrogen-containing bisphosphonate, resulted in a 1.86- and 1.63-fold increase in NLRP3/caspase-1-dependent IL-1β secretion by db/+ and db/db BMDMs, respectively, in comparison to BMDMs derived from non-treated mice (p<0.001). Importantly, systemic administration of pharmacological inhibitors of NLRP3 activation improved oral wound healing and suppressed BRONJ formation in db/db mice. Mechanistically, we showed that supplementation with intermediate metabolites of the mevalonate pathway, inhibitors of caspase-1 and NLRP3 activation, an antagonist for P2X7R, or a scavenger of reactive oxygen species (ROS), robustly abolished Zol-enhanced IL-1β release from macrophages in response to NLRP3 activation (p<0.001). Our findings suggest that diabetes-associated chronic inflammatory response may have contributed to impaired socket wound healing and rendered oral wound susceptible to the development of BRONJ via NLRP3 activation in macrophages. This article is protected by copyright. All rights reserved

Non-genetic induction of somatic cells into neural crest stem-like cells (NCSCs) is promising for potential cell-based therapies for post-traumatic peripheral nerve regeneration. Here, we report that human gingiva-derived mesenchymal stem cells (GMSCs) could be reproducibly and readily induced into NCSCs via non-genetic approaches. Compared to parental GMSCs, induced NCSC population had increased expression in NCSC-related genes and displayed robust differentiation into neuronal and Schwann-like cells. Knockdown of the expression of Yes-associated protein 1 (YAP1), a critical mechanosensor and mechanotransducer, attenuated the expression of NCSC-related genes; specific blocking of RhoA/ROCK activity and non-muscle myosin II (NM II)-dependent contraction suppressed YAP1 and NCSC-related genes and concurrently abolished neural spheroid formation in NCSCs. Using a rat model of facial nerve defect, implantation of NCSC-laden nerve conduits promoted functional regeneration of the injured nerve. These promising findings demonstrate that induced NCSCs derived from GMSCs represent an easily accessible and promising source of neural stem-like cells for peripheral nerve regeneration.