Demethylation of ITGAV accelerates osteogenic differentiation in a blast-induced heterotopic ossification in vitro cell culture model

Chromatin accessibility profiling reveals that human fibroblasts respond to mechanical stimulation in a cell-specific manner

Fibroblasts in the skin are highly heterogeneous, both in vivo and in vitro. One difference between follicular (dermal papilla fibroblasts [DP]) and interfollicular fibroblasts (papillary fibroblasts [PFi]) in vitro is their ability to differentiate in response to osteogenic media (OM), or mechanical stimulation. Here, we asked whether differences in the ability of DP and PFi to respond to differentiation stimuli are due to differences in chromatin accessibility. We performed chromatin accessibility and transcriptional profiling of DP and PFi in human skin, which arise from a common progenitor during development, yet display distinct characteristics in adult tissue and in vitro. We found that cells cultured in growth media had unique chromatin accessibility profiles; however, these profiles control similar functional networks. Upon introduction of a chemical perturbation (OM) to promote differentiation, we observed a divergence not only in the accessible chromatin signatures but also in the functional networks controlled by these signatures. The biggest divergence between DP and PFi was observed when we applied 2 perturbations to cells: growth in OM and mechanical stimulation (a shock wave [OMSW]). DP readily differentiate into bone in OMSW conditions, while PFi lack differentiation capability in vitro. In the DP we found a number of uniquely accessible promoters that controlled osteogenic interaction networks associated with bone and differentiation functions. Using ATAC-seq and RNA-seq we found that the combination of 2 stimuli (OMSW) could result in significant changes in chromatin accessibility associated with osteogenic differentiation, but only within the DP (capable of osteogenic differentiation). De novo motif analysis identified enrichment of motifs bound by the TEA domain (TEAD) family of transcription factors, and inter-cell comparisons (UpSet analysis) displayed large groups of genes to be unique to single cell types and conditions. Our results suggest that these 2 stimuli (OMSW) elicit cell-specific responses by modifying chromatin accessibility of osteogenic-related gene promoters.

A Functional Single-Nucleotide Polymorphism Upstream of the Collagen Type III Gene Is Associated with Catastrophic Fracture Risk in Thoroughbred Horses

Fractures caused by bone overloading are a leading cause of euthanasia in Thoroughbred racehorses. The risk of fatal fracture has been shown to be influenced by both environmental and genetic factors but, to date, no specific genetic mechanisms underpinning fractures have been identified. In this study, we utilised a genome-wide polygenic risk score to establish an in vitro cell system to study bone gene regulation in horses at high and low genetic risk of fracture. Candidate gene expression analysis revealed differential expression of COL3A1 and STAT1 genes in osteoblasts derived from high- and low-risk horses. Whole-genome sequencing of two fracture cases and two control horses revealed a single-nucleotide polymorphism (SNP) upstream of COL3A1 that was confirmed in a larger cohort to be significantly associated with fractures. Bioinformatics tools predicted that this SNP may impact the binding of the transcription factor SOX11. Gene modulation demonstrated SOX11 is upstream of COL3A1, and the region binds to nuclear proteins. Furthermore, luciferase assays demonstrated that the region containing the SNP has promoter activity. However, the specific effect of the SNP depends on the broader genetic background of the cells and suggests other factors may also be involved in regulating COL3A1 expression. In conclusion, we have identified a novel SNP that is significantly associated with fracture risk and provide new insights into the regulation of the COL3A1 gene.

The role of miRNA and lncRNA in heterotopic ossification pathogenesis

Heterotopic ossification (HO) is the formation of bone in non-osseous tissues, such as skeletal muscles. The HO could have a genetic or a non-genetic (acquired) background, that is, it could be caused by musculoskeletal trauma, such as burns, fractures, joint arthroplasty (traumatic HO), or cerebral or spinal insult (neurogenetic HO). HO formation is caused by the differentiation of stem or progenitor cells induced by local or systemic imbalances. The main factors described so far in HO induction are TGFβ1, BMPs, activin A, oncostatin M, substance P, neurotrophin-3, and WNT. In addition, dysregulation of noncoding RNAs, such as microRNA or long noncoding RNA, homeostasis may play an important role in the development of HO. For example, decreased expression of miRNA-630, which is responsible for the endothelial-mesenchymal transition, was observed in HO patients. The reduced level of miRNA-421 in patients with humeral fracture was shown to be associated with overexpression of BMP2 and a higher rate of HO occurrence. Down-regulation of miRNA-203 increased the expression of runt-related transcription factor 2 (RUNX2), a crucial regulator of osteoblast differentiation. Thus, understanding the various functions of noncoding RNAs can reveal potential targets for the prevention or treatment of HO.

Use of CGF in Oral and Implant Surgery: From Laboratory Evidence to Clinical Evaluation

Edentulism is the condition of having lost natural teeth, and has serious social, psychological, and emotional consequences. The need for implant services in edentulous patients has dramatically increased during the last decades. In this study, the effects of concentrated growth factor (CGF), an autologous blood-derived biomaterial, in improving the process of osseointegration of dental implants have been evaluated. Here, permeation of dental implants with CGF has been obtained by using a Round up device. These CGF-coated dental implants retained a complex internal structure capable of releasing growth factors (VEGF, TGF-β1, and BMP-2) and matrix metalloproteinases (MMP-2 and MMP-9) over time. The CGF-permeated implants induced the osteogenic differentiation of human bone marrow stem cells (hBMSC) as confirmed by matrix mineralization and the expression of osteogenic differentiation markers. Moreover, CGF provided dental implants with a biocompatible and biologically active surface that significantly improved adhesion of endothelial cells on CGF-coated implants compared to control implants (without CGF). Finally, data obtained from surgical interventions with CGF-permeated dental implants presented better results in terms of optimal osseointegration and reduced post-surgical complications. These data, taken together, highlight new and interesting perspectives in the use of CGF in the dental implantology field to improve osseointegration and promote the healing process.

Microarray analysis identification of key pathways and interaction network of differential gene expressions during osteogenic differentiation

BACKGROUND

Adult bone marrow-derived mesenchymal stem cells (BM-MSCs) are multipotent stem cells that can differentiate into three lineages. They are suitable sources for cell-based therapy and regenerative medicine applications. This study aims to evaluate the hub genes and key pathways of differentially expressed genes (DEGs) related to osteogenesis by bioinformatics analysis in three different days. The DEGs were derived from the three different days compared with day 0.

RESULTS

Gene expression profiles of GSE37558 were obtained from the Gene Expression Omnibus (GEO) database. A total of 4076 DEGs were acquired on days 8, 12, and 25. Gene ontology (GO) enrichment analysis showed that the non-canonical Wnt signaling pathway and lipopolysaccharide (LPS)-mediated signaling pathway were commonly upregulated DEGs for all 3 days. KEGG pathway analysis indicated that the PI3K-Akt and focal adhesion were also commonly upregulated DEGs for all 3 days. Ten hub genes were identified by CytoHubba on days 8, 12, and 25. Then, we focused on the association of these hub genes with the Wnt pathways that had been enriched from the protein-protein interaction (PPI) by the Cytoscape plugin MCODE.

CONCLUSIONS

These findings suggested further insights into the roles of the PI3K/AKT and Wnt pathways and their association with osteogenesis. In addition, the stem cell microenvironment via growth factors, extracellular matrix (ECM), IGF1, IGF2, LPS, and Wnt most likely affect osteogenesis by PI3K/AKT.

Concentrated Growth Factors (CGF) Induce Osteogenic Differentiation in Human Bone Marrow Stem Cells

Bone regeneration is a complex process regulated by several factors that control overlapping biological processes, coordinating interactions among distinct cell populations. There is a great interest in identifying new strategies for inducing osteogenesis in a safe and efficient manner. Concentrated Growth Factor (CGF) is an autologous blood derived product obtained by centrifugation of venous blood following the procedure set on the Silfradent device. In this study the effects of CGF on osteogenic differentiation of human Bone Marrow Stem Cells (hBMSC) in vitro have been investigated; hBMSC were cultured with CGF or osteogenic medium, for 21 days. The osteogenic differentiation was evaluated measuring alkaline phosphatase (ALP) enzyme activity, matrix mineralization by alizarin red staining and through mRNA and protein quantification of osteogenic differentiation markers by Real-time PCR and Western blotting, respectively. The treatment with CGF stimulated ALP activity and promoted matrix mineralization compared to control and seems to be more effective than osteogenic medium. Also, hBMSC lost mesenchymal markers and showed other osteogenic features. Our study showed for the first time that CGF alone is able to induce osteogenic differentiation in hBMSC. The application of CGF on hBMSC osteoinduction might offer new clinical and biotechnological strategies in the tissue regeneration field.

Bioinformatics combined with quantitative proteomics analyses and identification of potential biomarkers in cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) is an invasive malignancy arising from biliary epithelial cells; it is the most common primary tumour of the bile tract and has a poor prognosis. The aim of this study was to screen prognostic biomarkers for CCA by integrated multiomics analysis.

METHODS

The GSE32225 dataset was derived from the Gene Expression Omnibus (GEO) database and comprehensively analysed by using R software and The Cancer Genome Atlas (TCGA) database to obtain the differentially expressed RNAs (DERNAs) associated with CCA prognosis. Quantitative isobaric tags for relative and absolute quantification (iTRAQ) proteomics was used to screen differentially expressed proteins (DEPs) between CCA and nontumour tissues. Through integrated analysis of DERNA and DEP data, we obtained candidate proteins APOF, ITGAV and CASK, and immunohistochemistry was used to detect the expression of these proteins in CCA. The relationship between CASK expression and CCA prognosis was further analysed.

RESULTS

Through bioinformatics analysis, 875 DERNAs were identified, of which 10 were associated with the prognosis of the CCA patients. A total of 487 DEPs were obtained by using the iTRAQ technique. Comprehensive analysis of multiomics data showed that CASK, ITGAV and APOF expression at both the mRNA and protein levels were different in CCA compared with nontumour tissues. CASK was found to be expressed in the cytoplasm and nucleus of CCA cells in 38 (45%) of 84 patients with CCA. Our results suggested that patients with positive CASK expression had significantly better overall survival (OS) and recurrence-free survival (RFS) than those with negative CASK expression. Univariate and multivariate analyses demonstrated that negative expression of CASK was a significantly independent risk factor for OS and RFS in CCA patients.

CONCLUSIONS

CASK may be a tumour suppressor; its low expression is an independent risk factor for a poor prognosis in CCA patients, and so it could be used as a clinically valuable prognostic marker.

Isolating Dermal Papilla Cells from Human Hair Follicles Using Microdissection and Enzyme Digestion

The dermal papilla (DP) is a cluster of mesenchymal cells located at the bottom of the hair follicle. Cells within the DP interact with numerous other cell types within the follicle, including epithelial stem cells, matrix cells, and melanocytes, regulating their function. The diameter of the DP is directly proportional to the width of the hair shaft, and a decrease in both cell number and DP size is observed in hair loss conditions such as androgenetic alopecia. Conversely, microdissected ex vivo DP can instruct growth of de novo hair follicles. The study of DP cells and their role in human hair growth is often hampered by the technical challenge of DP isolation and culture. Here we describe a method used within our research group for isolating DP from human hair follicles.

Integrin subunit alpha V promotes growth, migration, and invasion of gastric cancer cells

Integrin subunit alpha V (ITGAV), a member of integrin family of extracellular matrix receptors, is involved in many types of cancer. In this study, the expression levels, clinical features and prognosis of ITGAV in gastric cancer (GC) patients were investigated, and the functional roles of ITGAV were also investigated. Cell Counting Kit-8 (CCK-8) assay was performed to examine the proliferation of GC cells. Transwell assays and wound-healing assays were conducted to explore the effect of ITGAV expression on GC cell migration and invasion. We found that ITGAV was overexpressed in both GC tissues and GC cells. ITGAV expression was positively correlated with lymph node metastasis and TNM stage of GC. High expression of ITGAV was associated with shorter overall survival (OS) and disease-free survival (DFS). Interestingly, the downregulation of ITGAV resulted in suppression of proliferation, migration, and invasion in GC cells. In conclusion, ITGAV is overexpressed in gastric cancer and is associated with poorer prognostic outcomes. ITGAV may serve as an important prognostic marker for GC staging and progression.