Foxc2 regulates osteogenesis and angiogenesis of bone marrow mesenchymal stem cells

Novel scaffold platforms for simultaneous induction osteogenesis and angiogenesis in bone tissue engineering: a cutting-edge approach

Despite the recent advances in the development of bone graft substitutes, treatment of critical size bone defects continues to be a significant challenge, especially in the elderly population. A current approach to overcome this challenge involves the creation of bone-mimicking scaffolds that can simultaneously promote osteogenesis and angiogenesis. In this context, incorporating multiple bioactive agents like growth factors, genes, and small molecules into these scaffolds has emerged as a promising strategy. To incorporate such agents, researchers have developed scaffolds incorporating nanoparticles, including nanoparticulate carriers, inorganic nanoparticles, and exosomes. Current paper provides a summary of the latest advancements in using various bioactive agents, drugs, and cells to synergistically promote osteogenesis and angiogenesis in bone-mimetic scaffolds. It also discusses scaffold design properties aimed at maximizing the synergistic effects of osteogenesis and angiogenesis, various innovative fabrication strategies, and ongoing clinical studies.

Spatiotemporal Characterization of Human Early Intervertebral Disc Formation at Single-Cell Resolution

The intervertebral disc (IVD) acts as a fibrocartilaginous joint to anchor adjacent vertebrae. Although several studies have demonstrated the cellular heterogeneity of adult mature IVDs, a single-cell transcriptomic atlas mapping early IVD formation is still lacking. Here, the authors generate a spatiotemporal and single cell-based transcriptomic atlas of human IVD formation at the embryonic stage and a comparative mouse transcript landscape. They identify two novel human notochord (NC)/nucleus pulposus (NP) clusters, SRY-box transcription factor 10 (SOX10)⁺ and cathepsin K (CTSK)⁺ , that are distributed in the early and late stages of IVD formation and they are validated by lineage tracing experiments in mice. Matrisome NC/NP clusters, T-box transcription factor T (TBXT)⁺ and CTSK⁺ , are responsible for the extracellular matrix homeostasis. The IVD atlas suggests that a subcluster of the vertebral chondrocyte subcluster might give rise to an inner annulus fibrosus of chondrogenic origin, while the fibroblastic outer annulus fibrosus preferentially expresseds transgelin and fibromodulin . Through analyzing intercellular crosstalk, the authors further find that notochordal secreted phosphoprotein 1 (SPP1) is a novel cue in the IVD microenvironment, and it is associated with IVD development and degeneration. In conclusion, the single-cell transcriptomic atlas will be leveraged to develop preventative and regenerative strategies for IVD degeneration.

Regulon active landscape reveals cell development and functional state changes of human primary osteoblasts in vivo

BACKGROUND

While transcription factor (TF) regulation is known to play an important role in osteoblast development, differentiation, and bone metabolism, the molecular features of TFs in human osteoblasts at the single-cell resolution level have not yet been characterized. Here, we identified modules (regulons) of co-regulated genes by applying single-cell regulatory network inference and clustering to the single-cell RNA sequencing profiles of human osteoblasts. We also performed cell-specific network (CSN) analysis, reconstructed regulon activity-based osteoblast development trajectories, and validated the functions of important regulons both in vivo and in vitro.

RESULTS

We identified four cell clusters: preosteoblast-S1, preosteoblast-S2, intermediate osteoblasts, and mature osteoblasts. CSN analysis results and regulon activity-based osteoblast development trajectories revealed cell development and functional state changes of osteoblasts. CREM and FOSL2 regulons were mainly active in preosteoblast-S1, FOXC2 regulons were mainly active in intermediate osteoblast, and RUNX2 and CREB3L1 regulons were most active in mature osteoblasts.

CONCLUSIONS

This is the first study to describe the unique features of human osteoblasts in vivo based on cellular regulon active landscapes. Functional state changes of CREM, FOSL2, FOXC2, RUNX2, and CREB3L1 regulons regarding immunity, cell proliferation, and differentiation identified the important cell stages or subtypes that may be predominantly affected by bone metabolism disorders. These findings may lead to a deeper understanding of the mechanisms underlying bone metabolism and associated diseases.

Mutation of foxl1 Results in Reduced Cartilage Markers in a Zebrafish Model of Otosclerosis

Bone diseases such as otosclerosis (conductive hearing loss) and osteoporosis (low bone mineral density) can result from the abnormal expression of genes that regulate cartilage and bone development. The forkhead box transcription factor FOXL1 has been identified as the causative gene in a family with autosomal dominant otosclerosis and has been reported as a candidate gene in GWAS meta-analyses for osteoporosis. This potentially indicates a novel role for foxl1 in chondrogenesis, osteogenesis, and bone remodelling. We created a foxl1 mutant zebrafish strain as a model for otosclerosis and osteoporosis and examined jaw bones that are homologous to the mammalian middle ear bones, and mineralization of the axial skeleton. We demonstrate that foxl1 regulates the expression of collagen genes such as collagen type 1 alpha 1a and collagen type 11 alpha 2, and results in a delay in jawbone mineralization, while the axial skeleton remains unchanged. foxl1 may also act with other forkhead genes such as foxc1a, as loss of foxl1 in a foxc1a mutant background increases the severity of jaw calcification phenotypes when compared to each mutant alone. Our zebrafish model demonstrates atypical cartilage formation and mineralization in the zebrafish craniofacial skeleton in foxl1 mutants and demonstrates that aberrant collagen expression may underlie the development of otosclerosis.

Role of long non-coding RNA H19 in the development of osteoporosis

Background

Osteoporosis is a widespread and serious metabolic bone disease. At present, revealing the molecular mechanisms of osteoporosis and developing effective prevention and treatment methods are of great significance to health worldwide. LncRNA is a non-coding RNA peptide chain with more than 200 nucleotides. Researchers have identified many lncRNAs implicated in the development of diseases and lncRNA H19 is an example.

Results

A large amount of evidence supports the fact that long non-coding RNA (lncRNA) genes, such as H19, have multiple, far-reaching effects on various biological functions. It has been found that lncRNA H19 has a role in the regulation of different types of cells in the body including the osteoblasts, osteocytes, and osteoclasts found in bones. Therefore, it can be postulated that lncRNA H19 affects the incidence and development of osteoporosis.

Conclusion

The prospect of targeting lncRNA H19 in the treatment of osteoporosis is promising because of the effects that lncRNA H19 has on the process of osteogenic differentiation. In this review, we summarize the molecular pathways and mechanisms of lncRNA H19 in the pathogenesis of osteoporosis and summarize the research progress of targeting H19 as a treatment option. Research is emerging that explores more effective treatment possibilities for bone metabolism diseases using molecular targets.

The Role of Forkhead Box Family in Bone Metabolism and Diseases

Forkhead box (Fox) family, an evolutionarily conserved family of transcription factors carrying the "Forkhead" motif, plays an indispensable role in human health and disease. Fox family genes are involved in cell differentiation, proliferation and apoptosis, embryonic development, aging, glucose and lipid metabolism, and immune regulation. The regulatory role of the Fox family in the context of bone metabolism and orthopedic diseases is an emerging research hotspot. In this review, we highlight the major molecular mechanisms underlying the regulatory role of Fox factors in bone metabolism, bone development, bone homeostasis, and bone diseases associated with inhibition or upregulation of Fox factors. In addition, we discuss the emerging evidence in the realm of Fox factor-based therapeutics.

The expression of AGGF1, FOXC2, and E-cadherin in esophageal carcinoma and their clinical significance

Angiogenic factor with G-patch and FHA domain 1 (AGGF1) is a newly initiator of angiogenesis. Forkhead box C2 (FOXC2) that is a member of the winged spiral transcription factor family plays an important role in epithelial-mesenchymal transition (EMT). Epithelial-cadherin (E-cad) that is an adhesion molecule is also involved in EMT. The purpose of this study is to investigate the expression of AGGF1, FOXC2, and E-cad in esophageal squamous cell carcinoma (ESCC) and their clinical significance.Immunohistochemistry was performed to investigate the expression of AGGF1, FOXC2, and E-cad in 170 ESCC specimens and corresponding normal esophageal mucosa tissues. Follow-up data was also collected.The positive rates of AGGF1 and FOXC2 expression were significantly higher in ESCC group when compared with the control group; the positive rate of E-cad expression was significantly lower in ESCC group when compared with the control group. Positive rates of AGGF1, FOXC2, and E-cad expression were significantly associated with grades of differentiation, tumor grades, lymph node metastasis stages, as well as tumor-node-metastasis stages. Kaplan-Meier analysis demonstrated that positive expression of AGGF1 or FOXC2 for ESCC patients had significantly unfavorably overall survival time when compared with patients with negative expression of AGGF1 or FOXC2; and positive expression of E-cad for ESCC patients had significantly longer overall survival time when compared with patients with negative expression of E-cad. Multivariate analysis indicated that AGGF1, FOXC2, and E-cad expression and tumor-node-metastasis stages were postoperative independent prognostic factors for ESCC patients.AGGF1, FOXC2, and E-cad may be considered promising biomarkers of ESCC patients' prognosis.

Circadian transcription factor Dbp promotes rat calvarial osteoprogenitors osteogenic differentiation through Kiss1/GnRH/E2 signaling pathway loop

To determine the mechanism by which D-site-binding protein (Dbp) regulates rat calvarial osteoprogenitors (OPCs) osteogenic differentiation. α-Smooth muscle actin (α-SMA) + rat calvarial OPCs were extracted and purified using immunomagnetic beads. Cells were transduced with Dbp-lentivirus and divided into Dbp knockdown, Dbp overexpression and vehicle groups. After osteogenic induction for 21 days, Alizarin red staining and alkaline phosphatase (ALP) activity were examined. Expression levels of Runx2, Ocn, Osterix, Bmp4, Kiss1, and GnRH were determined using a quantitative real-time polymerase chain reaction. The observed changes in Kisspeptin, GnRH, ERα, and Runx2 were further validated via Western blot analysis. Furthermore, E2 and GnRH secretion levels were detected via an enzyme-linked immunosorbent assay (ELISA). Chromatin immunoprecipitation (ChIP) and luciferase assay were used to assess the effects of Dbp on the Kiss1 gene promoter. The coexpression of Dbp and Kisspeptin or GnRH was also evaluated via immunofluorescence. Following osteogenic induction, Dbp overexpression significantly increased calcium nodule formation and ALP activity, as well as Runx2, Ocn, Osterix, Bmp4, Kiss1, and GnRH messenger RNA expression, while Dbp knockdown presented the opposite results. Western blot analysis and ELISA results showed that Dbp significantly promotes Runx2, E2/ERα, Kisspeptin, and GnRH expression. These findings were confirmed by the ChIP assay, which indicated that the estrogen receptor promotes Kisspeptin expression after binding to the Kiss1 gene promoter, which is regulated by Dbp. Immunofluorescence assay showed that Dbp coexpression with Kisspeptin or GnRH varied depending on Dbp expression levels. Collectively, the circadian transcription factor Dbp promotes α-SMA + rat calvarial OPCs osteoblastic differentiation through Kiss1/GnRH/E2 signaling pathway loop.

Integrated analysis of lncRNA-mRNA networks associated with an SLA titanium surface reveals the potential role of HIF1A-AS1 in bone remodeling

Microstructured titanium surface implants, such as typical sandblasted and acid-etched (SLA) titanium implants, are widely used to promote bone apposition in prosthetic treatment by dental implants following tooth loss. Although there are multiple factors associated with the superior osseointegration of an SLA titanium surface, the molecular mechanisms of long noncoding RNAs (lncRNAs) are still unclear. In this study, we characterized smooth (SMO) and SLA surfaces, and compared the osteoinduction of these surfaces using human bone marrow-derived mesenchymal stem cells (hBMSCs) in vitro and implants in a rat model in vivo. Then, we used microarrays and bioinformatics analysis to investigate the differential expression profiles of mRNAs and lncRNAs on SMO and SLA titanium surfaces. An lncRNA–mRNA network was constructed, which showed an interaction between lncRNA HIF1A antisense RNA 1 (HIF1A-AS1) and vascular endothelial growth factor. We further found that knockdown of HIF1A-AS1 significantly decreased osteogenic differentiation of hBMSCs. This study screened SLA-induced lncRNAs using a systemic strategy and showed that lncRNA HIF1A-AS1 plays a role in promotion of new bone formation in the peri-implant area, providing a novel insight for future surface modifications of implants.

Long non-coding RNA HIF1A-AS1 plays a role in SLA titanium surface-induced osteogenic differentiation of hBMSCs by regulating p38 MAPK.

Therapeutic Applications of Genes and Gene-Engineered Mesenchymal Stem Cells for Femoral Head Necrosis

Osteonecrosis of the femoral head (ONFH) is a common and disabling joint disease. Although there is no clear consensus on the complex pathogenic mechanism of ONFH, trauma, abuse of glucocorticoids, and alcoholism are implicated in its etiology. The therapeutic strategies are still limited, and the clinical outcomes are not satisfactory. Mesenchymal stem cells (MSCs) have been shown to exert a positive impact on ONFH in preclinical experiments and clinical trials. The beneficial properties of MSCs are due, at least in part, to their ability to home to the injured tissue, secretion of paracrine signaling molecules, and multipotentiality. Nevertheless, the regenerative capacity of transplanted cells is impaired by the hostile environment of necrotic tissue in vivo, limiting their clinical efficacy. Recently, genetic engineering has been introduced as an attractive strategy to improve the regenerative properties of MSCs in the treatment of early-stage ONFH. This review summarizes the function of several genes used in the engineering of MSCs for the treatment of ONFH. Further, current challenges and future perspectives of genetic manipulation of MSCs are discussed. The notion of genetically engineered MSCs functioning as a "factory" that can produce a significant amount of multipotent and patient-specific therapeutic product is emphasized.

Coactivation of Endogenous Wnt10b and Foxc2 by CRISPR Activation Enhances BMSC Osteogenesis and Promotes Calvarial Bone Regeneration

CRISPR activation (CRISPRa) is a burgeoning technology for programmable gene activation, but its potential for tissue regeneration has yet to be fully explored. Bone marrow-derived mesenchymal stem cells (BMSCs) can differentiate into osteogenic or adipogenic pathways, which are governed by the Wnt (Wingless-related integration site) signaling cascade. To promote BMSC differentiation toward osteogenesis and improve calvarial bone healing by BMSCs, we harnessed a highly efficient hybrid baculovirus vector for gene delivery and exploited a synergistic activation mediator (SAM)-based CRISPRa system to activate Wnt10b (that triggers the canonical Wnt pathway) and forkhead c2 (Foxc2) (that elicits the noncanonical Wnt pathway) in BMSCs. We constructed a Bac-CRISPRa vector to deliver the SAM-based CRISPRa system into rat BMSCs. We showed that Bac-CRISPRa enabled CRISPRa delivery and potently activated endogenous Wnt10b and Foxc2 expression in BMSCs for >14 days. Activation of Wnt10b or Foxc2 alone was sufficient to promote osteogenesis and repress adipogenesis in vitro. Furthermore, the robust and prolonged coactivation of both Wnt10b and Foxc2 additively enhanced osteogenic differentiation while inhibiting adipogenic differentiation of BMSCs. The CRISPRa-engineered BMSCs with activated Wnt10b and Foxc2 remarkably improved the calvarial bone healing after implantation into the critical-sized calvarial defects in rats. These data implicate the potentials of CRISPRa technology for bone tissue regeneration.

H19 and Foxc2 synergistically promotes osteogenic differentiation of BMSCs via Wnt-β-catenin pathway

OBJECTIVE

To investigate the mechanism of H19 on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).

METHODS

Ovariectomized (OVX) mouse model was established. RNA immunoprecipitation and RNA pull-down assays were performed to determine the correlation between H19 and forkhead box C2 (Foxc2). Chromatin immunoprecipitation assay was used to identify whether Foxc2 binds to the Wnt4 promoter region. Molecules expressions were measured by quantitative real-time polymerase chain reaction and western blot.

RESULTS

We found that H19 expression was reduced in the serum of patients with postmenopausal osteoporosis and BMSCs of OVX mice, and overexpression of H19 promoted osteogenic differentiation of BMSCs. Additionally, Foxc2 could bind to the Wnt4 promoter and promote its transcription. We also showed that H19 could bind to Foxc2, and H19/Foxc2 regulated Wnt promoter expression in a synergistic fashion, and H19/Foxc2 regulated osteogenic differentiation of BMSCs through Wnt-β-catenin pathway.

CONCLUSION

H19 and Foxc2 synergistically promoted osteogenic differentiation of BMSCs via Wnt-β-catenin pathway.

Foxc2 and BMP2 Induce Osteogenic/Odontogenic Differentiation and Mineralization of Human Stem Cells from Apical Papilla

As a transcription factor regulated by bone morphogenetic protein 2 (BMP2), Forkhead c2 (Foxc2) plays a pivot role in osteogenesis/odontogenesis. However, the role of Foxc2 and BMP2 in regulating osteo-/odontogenic differentiation and mineralization of stem cells from apical papilla (SCAP) is still uncertain. In this research, overexpression of Foxc2 gene significantly improved the proliferation of SCAP four days and eight days after transfection, but overexpression of both Foxc2 and BMP2 genes significantly inhibited the proliferation of SCAP eight days after transfection. RT-qPCR and western blot results indicated that SCAP-Foxc2-BMP2 significantly upregulated osteo-/odontogenic genes and proteins at most of the time points in SCAP after transfection. Moreover, SCAP-Foxc2-BMP2 formed notably more alkaline phosphatase-positive and alizarin red-positive mineralized nodules than other three group cells sixteen days after transfection. In conclusion, our findings revealed that Foxc2 and BMP2 synergistically promoted osteo-/odontogenic differentiation and mineralization of SCAP in vitro.

Osteoclast-Derived Extracellular Vesicles: Novel Regulators of Osteoclastogenesis and Osteoclast-Osteoblasts Communication in Bone Remodeling

Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, play an important role in cellular communication during skeletal growth and homeostasis. Bioactive molecules carried by EVs are transported to neighboring and distant cells to trigger a series of signaling cascades influencing bone homeostasis. The bioactive activities of osteoclast-derived EVs include regulation of osteoclastogenesis and osteoclast–osteoblast communication. As osteoclast-derived EVs have the potential to regulate osteoclasts and osteoblasts, their application in osteoporosis and other bone metabolic disorders is currently under investigation. However, very few reviews of osteoclast-derived EVs in bone remodeling regulation have yet been published. This article aims to review recent advances in this field, summarizing a new regulator of osteoclastogenesis and osteoclast–osteoblast communication mediated by osteoclast-derived EVs. We will analyze the major challenges in the field and potential for the therapeutic application of EVs.

FOXC2 and CLIP4 : a potential biomarker for synchronous metastasis of ≤7-cm clear cell renal cell carcinomas

Renal cell carcinomas (RCC) smaller than 7-cm are heterogeneous and exhibit metastatic potential in approximately 15% of cases. Although large-scale characterization of mutations in clear cell RCC (ccRCC), the most common RCC subtype, has been established, the genetic alterations related to ≤7-cm ccRCCs undergoing synchronous metastasis are poorly understood. To discover biomarkers that can be used to estimate the risk of synchronous metastasis in these ccRCC patients, we performed whole exome sequencing on the formalin-fixed paraffin-embedded (FFPE) samples of 10 ccRCC patients with ≤7-cm tumors and synchronous metastasis and expanded our study using The Cancer Genome Atlas (TCGA) ccRCC dataset (n = 201). Recurrent mutations were selected according to functional prediction and statistical significance. Mutations in three candidate genes, RELN (1 out of 10), FOXC2 (1 out of 10), and CLIP4 (2 out of 10) were found in expanded analysis using a TCGA cohort. Furthermore, siRNA-mediated target gene knockdown (FOXC2 and CLIP4) and overexpression (RELN) assays showed that FOXC2 and CLIP4 significantly increased cell migration and viability in ccRCCs. Our study demonstrated that FOXC2 and CLIP4 activity correlates to the presence of ≤7-cm ccRCCs with synchronous metastasis and may be potential molecular predictors of synchronous metastasis of ≤7-cm ccRCCs.

Emerging roles and mechanisms of FOXC2 in cancer

Forkhead box protein C2 (FOXC2), a transcription factor of the forkhead/winged-helix family, is required for embryonic and prenatal development. FOXC2 acts as a crucial modulator during both angiogenesis and lymphangiogenesis via multiple angiogenic and lymphangiogenic pathways, respectively. Although recent studies have shed light on the emerging role of FOXC2 in cancer, very little is known about the precise underlying mechanisms. The purpose of this review is to summarize the current understanding of FOXC2 and provide potential mechanistic explanations of the relationship between FOXC2 and cancer, as well as discuss the prospect for future research in the promising prognostic value of FOXC2 in cancer.

Role and importance of the expression of transcription factor FOXC2 in cervical cancer

The aim of the present study was to investigate the relationship between the expression of transcription factor forkhead box C2 (FOXC2) and the clinical features of cervical cancer. A total of 66 patients with cervical cancer, 42 patients with cervical intraepithelial neoplasia (CIN) and 25 patients with cervical inflammation were enrolled. The positive expression rates and expression levels of mRNA of FOXC2, E-cadherin, N-cadherin, vascular endothelial growth factor (VEGF), stromal cell-derived factor-1 (SDF-1), Notch protein and lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) in cervical tissues were detected using immunohistochemistry and RT-PCR. The positive expression rates and expression levels of mRNA of FOXC2, N-cadherin, VEGF, SDF-1, Notch and LYVE-1 in cervical cancer were significantly higher than those in CIN, and those in the inflammatory tissues were the lowest, while the positive expression rate of E-cadherin in cervical cancer was lower than that in CIN, and that in the inflammatory tissues was the highest (P<0.05). The positive expression rates of FOXC2, N-cadherin, VEGF, SDF-1, Notch and LYVE-1 in patients with cervical cancer [human papillomavirus (HPV) positive, squamous cell carcinoma, Stages III–IV, maximal diameter ≥3.8 cm and low differentiation] were increased, and the positive expression rate of E-cadherin was decreased (P<0.05). Correlation analysis revealed that FOXC2 was positively correlated with the positive expression rates of N-cadherin, VEGF, SDF-1, Notch and LYVE-1, and negatively correlated with E-cadherin (P<0.05). In conclusion, the high expression of FOXC2 is correlated with the HPV infection, pathological pattern, clinical stage, tumor diameter and differentiation grade of cervical cancer, which may be involved in the epithelial-mesenchymal transition, vascular and matrix formation, Notch signaling pathway and lymphangiogenesis.

Acute Phosphate Restriction Impairs Bone Formation and Increases Marrow Adipose Tissue in Growing Mice

Phosphate plays a critical role in chondrocyte maturation and skeletal mineralization. Studies examining the consequences of dietary phosphate restriction in growing mice demonstrated not only the development of rickets, but also a dramatic decrease in bone accompanied by increased marrow adipose tissue (MAT). Thus studies were undertaken to determine the effects of dietary phosphate restriction on bone formation and bone marrow stromal cell (BMSC) differentiation. Acute phosphate restriction of 28-day-old mice profoundly inhibited bone formation within 48 hours. It also resulted in increased mRNA expression of the early osteolineage markers Sox9 and Runt-related transcription factor 2 (Runx2), accompanied by decreased expression of the late osteolineage markers Osterix and Osteocalcin in BMSCs and osteoblasts, suggesting that phosphate restriction arrests osteoblast differentiation between Runx2 and Osterix. Increased expression of PPARγ and CEBPα, key regulators of adipogenic differentiation, was observed within 1 week of dietary phosphate restriction and was followed by a 13-fold increase in MAT at 3 weeks of phosphate restriction. In vitro phosphate restriction did not alter BMSC osteogenic or adipogenic colony formation, implicating aberrant paracrine or endocrine signaling in the in vivo phenotype. Because BMP signaling regulates the transition between Runx2 and Osterix, this pathway was interrogated. A dramatic decrease in pSmad1/5/9 immunoreactivity was observed in the osteoblasts of phosphate-restricted mice on day 31 (d31) and d35. This was accompanied by attenuated expression of the BMP target genes Id1, KLF10, and Foxc2, the latter of which promotes osteogenic and angiogenic differentiation while impairing adipogenesis. A decrease in expression of the Notch target gene Hey1, a BMP-regulated gene that governs angiogenesis, was also observed in phosphate-restricted mice, in association with decreased metaphyseal marrow vasculature. Whereas circulating phosphate levels are known to control growth plate maturation and skeletal mineralization, these studies reveal novel consequences of phosphate restriction in the regulation of bone formation and osteoblast differentiation. © 2016 American Society for Bone and Mineral Research.

Early Mandibular Distraction to Relieve Robin Severe Airway Obstruction in Two Siblings with Lymphedema-Distichiasis Syndrome

Although micrognathia and cleft palate have been reported in patients with Lymphedema-distichiasis syndrome (LDS), the classic Robin sequence with glossoptosis and airway obstruction has not been previously described in patients with genetically confirmed LDS. Here we report on two female siblings with LDS confirmed by a FOXC2 mutation who presented at birth with severe airway obstruction related to Robin sequence. Respiratory obstruction was successfully managed by early distraction osteogenesis. Our report highlights the unusual occurrence of Robin sequence in LDS patients and advises distraction osteogenesis to resolve breathing problems in LDS patients who present with Robin related severe airway obstruction.

FoxC2 Enhances BMP7-Mediated Anabolism in Nucleus Pulposus Cells of the Intervertebral Disc

Bone-morphogenetic protein-7 (BMP-7) is a growth factor that plays a major role in mediating anabolism and anti-catabolism of the intervertebral disc matrix and cell homeostasis. In osteoblasts, Forkhead box protein C2 (FoxC2) is a downstream target of BMPs and promotes cell proliferation and differentiation. However, the role FoxC2 may play in degenerative human intervertebral disc tissue and the relationship between FoxC2 and BMP-7 in nucleus pulposus (NP) cells remain to be elucidated. This study aims to investigate the presence and signaling mechanisms of FoxC2 in degenerative human intervertebral disc tissue and NP cells. Western blot and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses were used to measure FoxC2 expression in the NP tissue and cells. Transfections were carried out to measure the effect of FoxC2 on BMP-7-mediated extracellular matrix upregulation. Adenoviral knock-down of Smad1 was performed to investigate the mechanism of BMP-7-induced FoxC2 expression. In degenerative NP tissue, FoxC2 was markedly upregulated and positively correlated with increased disc degeneration. Induction of NP cell proliferation was confirmed by using cell counting kit-8 assay, immunocytochemistry and real-time qRT-PCR for Ki67. FoxC2 led to decreased noggin expression and increased Smad1/5/8 phosphorylation. During combined treatment with BMP-7, FoxC2 greatly potentiated anabolism through synergistic mechanisms on ECM formation. Combination therapy using BMP-7 and FoxC2 may be beneficial to the treatment of intervertebral disc degeneration.

Sika Deer Antler Collagen Type I-Accelerated Osteogenesis in Bone Marrow Mesenchymal Stem Cells via the Smad Pathway

Deer antler preparations have been used to strengthen bones for centuries. It is particularly rich in collagen type I. This study aimed to unravel part of the purported bioremedial effect of Sika deer antler collagen type I (SDA-Col I) on bone marrow mesenchymal stem cells. The results suggest that SDA-Col I might be used to promote and regulate osteoblast proliferation and differentiation. SDA-Col I might potentially provide the basis for novel therapeutic strategies in the treatment of bone injury and/or in scaffolds for bone replacement strategies. Finally, isolation of SDA-Col I from deer antler represents a renewable, green, and uncomplicated way to obtain a biomedically valuable therapeutic.

SGK3 (CISK) may induce tumor angiogenesis (Hypothesis)

Serum- and glucocorticoid-inducible protein kinase 3 (SGK3), also known as cytokine-independent survival kinase (CISK), encoded by chromosome 8q12.2, is a downstream mediator of phosphatidylinositol 3-kinase (PI3K) oncogenic signaling. As a downstream target of PI3K, SGK3 has been reported to mediate pivotal roles in oncogenic progress in various cancers, including breast cancer, ovarian cancer and hepatocellular carcinoma. Functionally parallel to v-akt murine thymoma viral oncogene homolog (AKT)/protein kinase B, SGK3 serves as a hallmark mediating glycogen synthase kinase-β (GSK3-β), B-cell lymphoma (Bcl)-2-associated death promoter, forkead family of transcription factors, Bcl-extra large, Bcl-2, mammalian target of rapamycin, C-X-C chemokine receptor type 4 (CXCR4) and numerous other molecules in cell proliferation, growth, survival, migration and even tumor angiogenesis. Tumor angiogenesis is recognized as an essential step for tumor growth, invasion and metastasis, and it has become an intriguing target for anticancer drug development for tumor investigators worldwide. An abundance of experiments have been performed to investigate the role of the phosphoinositide 3-kinase (PI3K)/AKT pathway in regulating tumor angiogenesis. The mechanism of angiogenesis regulated by the PI3K/AKT pathway is, to a certain extent, clear. Although a number of SGK3 target molecules, including CXCR4 and GSK3β, have demonstrated potential roles in promoting angiogenesis, the exact association between angiogenesis and SGK3 remains unclear. Thus, we hypothesize that SGK3, parallel to AKT, may also be important in mediating angiogenesis. Identifying the role of SGK3 in tumor angiogenesis will certainly present a novel perspective on the malignant transformation of tumors, as well as a target for tumor therapy.

Transforming growth factor beta 3 involved in the pathogenesis of synovial chondromatosis of temporomandibular joint

Synovial chondromatosis (SC) of temporomandibular joint is rare proliferative disorder featured by the formation of cartilaginous nodules in synovium and joint space. Transforming growth factor beta 3 (TGF-β3) is closely related to chondrogenic differentiation, and might participate in pathogenesis of SC. We discovered that increased quantity of synoviocytes and blood vessels were observed in SC synovium. The vessel wall and sublining fibroblasts were stained positively by the antibodies against TGF-β3, fibroblast growth factor 2 (FGF-2), and CD34. In loose bodies (LBs), TGF-β3 was mainly expressed in chondrocytes and FGF-2 was expressed in chondrocytes, fibroblasts, and vessel walls. Expressions of TGF-β1, TGF-β3, FGF-2, Sox9, Wnt-4, Foxc2, and VEGF-A mRNA were significantly higher in SC synovium. Stimulation of TGF-β3 on synoviocytes increased alkaline phosphatase (ALP) activity and expressions of chondrogenic genes (Sox9, Col2α1, Aggrecan, Wnt-4, and Wnt-11), osteogenic genes (Runx2, Foxc2, osteocalcin, and Col1α1), and VEGF-A, but failed to influence FGF-2 expression. However, the addition of FGF-2 increased TGF-β3 expression. In conclusion, TGF-β3 existed in synovium and LBs of SC, and was responsible for the pathogenesis of SC.

Comparative investigation of human amniotic epithelial cells and mesenchymal stem cells for application in bone tissue engineering

Emerging evidence suggests amniotic epithelial cells (AECs) as a promising source of progenitor cells in regenerative medicine and bone tissue engineering. However, investigations comparing the regenerative properties of AECs with other sources of stem cells are particularly needed before the feasibility of AECs in bone tissue engineering can be determined. This study aimed to compare human amniotic epithelial cells (hAECs), human bone marrow mesenchymal stem cells (hBMSCs), and human amniotic fluid derived mesenchymal stem cells (hAFMSCs) in terms of their morphology, proliferation, immunophenotype profile, and osteogenic capacity in vitro and in vivo. Not only greatly distinguished by cell morphology and proliferation, hAECs, hAFMSCs, and hBMSCs exhibited remarkably different signature regarding immunophenotypical profile. Microarray analysis revealed a different expression profile of genes involved in ossification along the three cell sources, highlighting the impact of different anatomical origin and molecular response to osteogenic induction on the final tissue-forming potential. Furthermore, our data indicated a potential role of FOXC2 in early osteogenic commitment.

Transplantation of bone marrow stromal cells enhances infiltration and survival of CNP and Schwann cells to promote axonal sprouting following complete transection of spinal cord in adult rats

This study aimed to investigate the roles of bone marrow stromal cells (BMSCs) in promoting axonal regeneration after complete transection of spinal cord in adult rats. Transplantation was done 9 days after injury. Only a few BMSCs were detected at the injury site 8 weeks after transplantation, yet there was robust growth of axons. The scarcity of surviving BMSCs may attribute to the adverse conditions in their ambient environment. In this connection, the immediate accumulation of a large number of macrophages/reactive microglia following BMSCs transplantation and subsequent cavitation of tissues may be detrimental to their survival. An unexpected finding following BMSCs transplantation was the marked increase in the nestin, GFAP, NF200, olig 3 and CNP positive cells at the injury site. Immunoelectron microscopy showed CNP cells were oval or fibroblast-like and had multiple perineurial-like compartments with long extending filopodia. The spatial relationship between regenerating axons and CNP-positive cells was also confirmed by double immunofluorescence staining. Our results suggest that transplantation of BMSCs elicits the influx and survival of local cells including CNP positive cells and Schwann cells into injury site, which provide structural support for the axon regeneration and remyelination after spinal cord injury.

Fibroblast growth factor 2 involved in the pathogenesis of synovial chondromatosis of temporomandibular joint

BACKGROUND

Synovial chondromatosis (SC) of temporomandibular joint (TMJ) is a rare proliferative disorder characterized by the formation of cartilaginous or osteocartilaginous nodules in synovium and joint space. Fibroblast growth factor 2 (FGF-2) is frequently applied in chondrogenic differentiation assays. Therefore, we hypothesized that FGF-2 might involved in the pathogenesis of SC.

METHODS

SC synovium and loose bodies (LBs) specimens were observed by histological and immunohistochemical methods. Real-time PCR was conducted for comparing genes expressions in SC and normal synovium. SC synoviocytes were stimulated by FGF-2 in the presence or absence of its antagonist long pentraxin-3 (PTX3) for 6 days. Real-time PCR and alkaline phosphatase (ALP) activity were performed to examine the effects exerted by FGF-2 and PTX3.

RESULTS

SC synovium, no matter facing the articular cavity or covering LB, was characterized by increased quantity of synoviocytes and blood vessels. FGF-2 was expressed in chondrocytes and fibroblast-like cells of LBs, and the wall of blood vessels. Expressions of chondrogenic genes (Sox9 and Wnt-4), osteogenic genes (Foxc2), FGF-2, and VEGF-A mRNA were significantly higher in SC synovium than that of the control group. The stimulation of FGF-2 on SC synoviocytes increased ALP activity and expressions of chondrogenic genes (Sox9, Col2α1, and Aggrecan), osteogenic genes (Foxc2, osteocalcin, and Col1α1), and VEGF-A, but PTX3 inhibited these effects.

CONCLUSION

FGF-2 was responsible for the formation of cartilaginous loose bodies and involved in the pathogenesis of SC.