Effect of different biomaterials on the expression pattern of the transcription factor Ets2 in bone-like constructs

ERK1-mediated immunomodulation of mesenchymal stem cells ameliorates inflammatory disorders

Immune system disorders, especially T cell disorders, are important therapeutic targets of mesenchymal stem cells (MSCs) in many autoimmune diseases (ADs). Although extracellular regulated protein kinases (ERKs) play a role in MSC therapy by promoting T cell apoptosis, the mechanism remains unclear. Our findings indicate that ERK1-/- bone marrow MSCs (BMMSCs), but not ERK2-/- BMMSCs, failed to promote T cell apoptosis due to incapacity to activate the ETS2/AURKA/NF-κB/Fas/MCP-1 cascade. Moreover, ERK1-/- BMMSCs were unable to upregulate regulatory T cells and suppress T helper 17 cells. Licochalcone A (LA), which promotes ERK pathway activation, enhanced the therapeutic efficacy of MSC therapy in ulcerative colitis and collagen-induced arthritis mice. Our findings suggest that ERK1, but not ERK2, plays a crucial role in regulating T cells in MSCs. LA-treated MSCs provide a strategy to improve the efficacy of MSC-based treatments for ADs.

Investigation of candidate genes and mechanisms underlying postmenopausal osteoporosis using bioinformatics analysis

The present study aimed to determine candidate genes, chemicals and mechanisms underlying postmenopausal osteoporosis (PMOP). A gene expression profile (accession no. GSE68303), which included 12 tissue samples from ovariectomized mice (OVX group) and 11 normal tissue samples from sham surgery mice (control group), was downloaded from the Gene Expression Omnibus database. The identification of differentially expressed genes (DEGs), and Gene Ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses, was performed, followed by an investigation of protein‑protein interactions (PPI), PPI modules, transcription factors (TFs) and chemicals. A total of 784 upregulated and 729 downregulated DEGs between the two groups were identified. Furthermore, 2 upregulated modules and 6 downregulated modules were determined. The upregulated DEGs in modules were enriched in 'sensory perception of smell' function and 'olfactory transduction' pathway, and a number of genes belonging to the olfactory receptor (OLFR) family were identified in upregulated modules. The downregulated DEGs in modules were enriched in 'DNA replication initiation' function and 'cell cycle' pathway. A total of 8 TFs, including SP1 TF (SP1) and protein C‑ets‑1 (ETS1), were associated with PMOP. Furthermore, estradiol and resveratrol were identified as key chemicals in the chemical‑gene interaction network. Therefore, TFs, including SP1 and ETS1, in addition to members of the OLFR gene family, may be employed as novel targets for treatment of PMOP. Furthermore, functions including 'sensory perception of smell' and 'replication initiation', and 'olfactory transduction' and 'cell cycle' pathways, may serve roles in PMOP. In addition, based on the chemical‑gene interaction network, estradiol and resveratrol may also be considered for the treatment PMOP.

A three-dimensional tissue culture model of bone formation utilizing rotational co-culture of human adult osteoblasts and osteoclasts

Living bone is a complex, three-dimensional composite material consisting of numerous cell types spatially organized within a mineralized extracellular matrix. To date, mechanistic investigation of the complex cellular level cross-talk between the major bone-forming cells involved in the response of bone to mechanical and biochemical stimuli has been hindered by the lack of a suitable in vitro model that captures the "coupled" nature of this response. Using a novel rotational co-culture approach, we have generated large (>4mm diameter), three-dimensional mineralized tissue constructs from a mixture of normal human primary osteoblast and osteoclast precursor cells without the need for any exogenous osteoconductive scaffolding material that might interfere with such cell-cell interactions. Mature, differentiated bone constructs consist of an outer region inhabited by osteoclasts and osteoblasts and a central region containing osteocytes encased in a self-assembled, porous mineralized extracellular matrix. Bone constructs exhibit morphological, mineral and biochemical features similar to remodeling human trabecular bone, including the expression of mRNA for SOST, BGLAP, ACP5, BMP-2, BMP-4 and BMP-7 within the construct and the secretion of BMP-2 protein into the medium. This "coupled" model of bone formation will allow the future investigation of various stimuli on the process of normal bone formation/remodeling as it relates to the cellular function of osteoblasts, osteoclasts and osteocytes in the generation of human mineralized tissue.

Cell-scaffold transplant of hydrogel seeded with rat bone marrow progenitors for bone regeneration

Bone is the second most frequently transplanted tissue in humans and efforts are focused on developing cell-scaffold constructs which can be employed for autologous implantation in place of allogenic transplants. The objective of the present study was to examine the efficacy of a gelatin-based hydrogel scaffold to support osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (MSCs) and its application in a cranial defect model. MSCs which were cultured on hydrogel under osteogenic conditions demonstrated typical osteogenic differentiation which included cluster formation with positive Alizarin Red S staining, sedimentation of calcium phosphate as defined by SEM and EDS spectroscopy and expression of mRNA osteogenic markers. Empty scaffolds or those containing either differentiated cells or naïve cells were implanted into cranial defects of athymic nude mice and the healing process was followed by μCT. Substantial bone formation (65%) was observed with osteogenic cell-scaffold constructs when compared to the naïve cell construct (25%) and the cell free scaffold (10%). Results demonstrated the potential of hydrogel scaffolds to serve as a supportive carrier for bone marrow-derived MSCs.