BMP signaling in skeletal development

Genome-wide identification, evolution, and expression analysis of the bone morphogenetic protein gene family in Myxocyprinus asiaticus

Bone morphogenetic proteins (BMPs) are important growth factors belonging to the TGF-β superfamily. These factors not only play a vital role in skeleton formation in young fish but also regulate the morphological development of M. asiaticus, with Group II genes regulating morphology mainly during the juvenile stage. This study investigated how BMP genes regulate Myxocyprinus asiaticus development and function and explored the role of the BMP family in fish morphological development. In this study, 43 BMPs were identified and classified into five groups: BMP1/3/11/15 (Group I), BMP12/13/14 (Group II), BMP2/4/16 (Group III), BMP9/10 (Group IV), and BMP5/6/7/8 (Group V). Analyses of the gene structures and conserved motifs revealed the conservation of the BMP gene family in M. asiaticus. In M. asiaticus, gene fragmentation, duplication, and 4R whole-genome duplication events contributed to BMP gene family expansion. Furthermore, expression pattern analysis and qRT-PCR revealed that changes in M. asiaticus BMP gene expression during different developmental stages were due to body size alterations, highlighting the major impact of the BMP gene on body size variation in this species. Our study provides fundamental data for investigating the morphological development of M. asiaticus and lays the framework for understanding the genetic mechanisms of body size variation in scleractinian fishes, with potential applications in the artificial breeding and conservation of M. asiaticus.

RUNX1 is a key inducer of human hematopoiesis controlling non-hematopoietic mesodermal development

The RUNX1/AML1 transcription factor is one of the key regulators of definitive hematopoietic development in mice. However, its role in early human hematopoiesis remains poorly investigated. In this study, we integrated a tdTomato reporter cassette into the RUNX1 locus of human pluripotent stem cells (hPSCs) to monitor and block the expression of the gene during hPSC differentiation. This approach demonstrated that expression of RUNX1 starts early in mesodermal specification focusing later on hemogenic endothelium (HE) and nascent hematopoietic cells. Lack of RUNX1 halted the development of CD43+ and CD235-CD45+ hematopoietic cells, preventing the production of clonogenic hematopoietic progenitors including the multilineage ones. The abrogation of RUNX1 resulted in the failure of definitive lineages, specifically T and NK cells. Remarkably, we instead observed the accumulation of RUNX1-null HE cells at the stage of blood cell generation. Moreover, the loss of the gene biased the development toward the lineage of CD43-CD146+CD90+CD73+ mesenchymal cells. RNA-seq analysis of RUNX1-null cells revealed the downregulation of top-level hematopoietic transcription factor genes and the reciprocal upregulation of genes associated with non-hematopoietic cells of mesodermal origin. Forced expression of RUNX1c in differentiating RUNX1-null hPSCs effectively rescued the development of CD45+ myeloid cells and megakaryocytes. Our data demonstrate that RUNX1 is a top hematopoietic inducer that simultaneously controls the expansion of non-hematopoietic lineages.

Epithelial-mesenchymal crosstalk: the scriptwriter of craniofacial morphogenesis

Epithelial-mesenchymal interactions (EMI) are fundamental mechanisms in regulating development and organogenesis. Here we summarized the signaling mechanisms involved in EMI in the major developmental events during craniofacial morphogenesis, including neural crest cell induction, facial primordial growth as well as fusion processes. Regional specificity/polarity are demonstrated in the expression of most signaling molecules that usually act in a mutually synergistic/antagonistic manner. The underlying mechanisms of pathogenesis due to disrupted EMI was also discussed in this review.

Expression of Kielin/chordin-like protein is regulated by BMP-2 in osteoblasts

Bone morphogenetic protein (BMP), an osteoinductive factor, is a cytokine that induces osteoblast differentiation and mineralization, and expected to be applicable for hard tissue reconstruction. Kielin/chordin-like protein (Kcp), a member of the family of cysteine-rich proteins, enhances BMP signaling. The present study found that expression of Kcp in osteoblasts was induced by BMP-2 in a concentration- and time-dependent manner. Up-regulation of Kcp by BMP-2 was inhibited by Dorsomorphin, a SMAD signaling inhibitor. The involvement of up-regulation of Kcp by BMP-2 in induction of osteoblast differentiation by BMP-2 was also examined, which showed that suppression of Kcp expression by si Kcp partially inhibited induction of osteoblast differentiation and mineralization by BMP-2. Together, these results suggest that Kcp induced by BMP-2 functions to provide positive feedback for promotion of osteoblastic differentiation and mineralization by BMP-2 in osteoblasts.

Fibrin-konjac glucomannan-black phosphorus hydrogel scaffolds loaded with nasal ectodermal mesenchymal stem cells accelerated alveolar bone regeneration

BACKGROUND

Effective treatments for the alveolar bone defect remain a major concern in dental therapy. The objectives of this study were to develop a fibrin and konjac glucomannan (KGM) composite hydrogel as scaffolds for the osteogenesis of nasal mucosa-derived ectodermal mesenchymal stem cells (EMSCs) for the regeneration of alveolar bone defect, and to investigate the osteogenesis-accelerating effects of black phosphorus nanoparticles (BPNs) embedded in the hydrogels.

METHODS

Primary EMSCs were isolated from rat nasal mucosa and used for the alveolar bone recovery. Fibrin and KGM were prepared in different ratios for osteomimetic hydrogel scaffolds, and the optimal ratio was determined by mechanical properties and biocompatibility analysis. Then, the optimal hydrogels were integrated with BPNs to obtain BPNs/fibrin-KGM hydrogels, and the effects on osteogenic EMSCs in vitro were evaluated. To explore the osteogenesis-enhancing effects of hydrogels in vivo, the BPNs/fibrin-KGM scaffolds combined with EMSCs were implanted to a rat model of alveolar bone defect. Micro-computed tomography (CT), histological examination, real-time quantitative polymerase chain reaction (RT-qPCR) and western blot were conducted to evaluate the bone morphology and expression of osteogenesis-related genes of the bone regeneration.

RESULTS

The addition of KGM improved the mechanical properties and biodegradation characteristics of the fibrin hydrogels. In vitro, the BPNs-containing compound hydrogel was proved to be biocompatible and capable of enhancing the osteogenesis of EMSCs by upregulating the mineralization and the activity of alkaline phosphatase. In vivo, the micro-CT analysis and histological evaluation demonstrated that rats implanted EMSCs-BPNs/fibrin-KGM hydrogels exhibited the best bone reconstruction. And compared to the model group, the expression of osteogenesis genes including osteopontin (Opn, p < 0.0001), osteocalcin (Ocn, p < 0.0001), type collagen (Col , p < 0.0001), bone morphogenetic protein-2 (Bmp2, p < 0.0001), Smad1 (p = 0.0006), and runt-related transcription factor 2 (Runx2, p < 0.0001) were all significantly upregulated.

CONCLUSIONS

EMSCs/BPNs-containing fibrin-KGM hydrogels accelerated the recovery of the alveolar bone defect in rats by effectively up-regulating the expression of osteogenesis-related genes, promoting the formation and mineralisation of bone matrix.

PAI-1 transfected-conditioned media promotes osteogenic differentiation of hBMSCs

Reconstruction of injured bone remains challenging in the clinic owing to the lack of suitable bone grafts. The utilization of PAI-1 transfected-conditioned media (P-CM) has demonstrated its ability to facilitate the differentiation process of mesenchymal stem cells (MSCs), potentially serving as a crucial mediator in tissue regeneration. This research endeavored to explore the therapeutic potential of P-CM concerning the differentiation of human bone marrow mesenchymal stem cells (hBMSCs). To assess new bone formation, a rat calvaria critical defect model was employed, while in vitro experiments involved the use of the alizarin Red-S mineral induction test. In the rat calvaria critical defect model, P-CM treatment resulted in significan new bone formation. In vitro, P-CM treated hBMSCs displayed robust osteogenesis compared to the control group, as demonstrated by the mineral induction test using alizarin Red-S. P-CM with hydroxyapatite/β-tricalcium phosphate/fibrin gel treatment significantly exhibited new bone formation, and the expression of osteogenic associated markers was enhanced in the P-CM-treated group. In conclusion, results demonstrate that P-CM treatment significantly enhanced the osteogenic differantiation efficiency and new bone formation, thus could be used as an ideal therapeutic biomolecule for constructing bone-specific implants, especially for orthopedic and dental applications.

Bone Morphogenic Proteins in Pediatric Diffuse Midline Gliomas: How to Make New Out of Old?

The BMP pathway is one of the major signaling pathways in embryonic development, ontogeny and homeostasis, identified many years ago by pioneers in developmental biology. Evidence of the deregulation of its activity has also emerged in many cancers, with complex and sometimes opposing effects. Recently, its role has been suspected in Diffuse Midline Gliomas (DMG), among which Diffuse Intrinsic Pontine Gliomas (DIPG) are one of the most complex challenges in pediatric oncology. Genomic sequencing has led to understanding part of their molecular etiology, with the identification of histone H3 mutations in a large proportion of patients. The epigenetic remodeling associated with these genetic alterations has also been precisely described, creating a permissive context for oncogenic transcriptional program activation. This review aims to describe the new findings about the involvement of BMP pathway activation in these tumors, placing their appearance in a developmental context. Targeting the oncogenic synergy resulting from this pathway activation in an H3K27M context could offer new therapeutic perspectives based on targeting treatment-resistant cell states.

TSLP enhances progestin response in endometrial cancer via androgen receptor signal pathway

BACKGROUND

The enriched proteins within in vitro fertilisation (IVF)-generated human embryonic microenvironment could reverse progestin resistance in endometrial cancer (EC).

METHODS

The expression of thymic stromal lymphopoietin (TSLP) in EC was evaluated by immunoblot and IHC analysis. Transcriptome sequencing screened out the downstream pathway regulated by TSLP. The role of TSLP, androgen receptor (AR) and KANK1 in regulating the sensitivity of EC to progestin was verified through a series of in vitro and in vivo experiments.

RESULTS

TSLP facilitates the formation of a BMP4/BMP7 heterodimer, resulting in activation of Smad5, augmenting AR signalling. AR in turn sensitises EC cells to progestin via KANK1. Downregulation of TSLP, loss of AR and KANK1 in EC patients are associated with tumour malignant progress. Moreover, exogenous TSLP could rescue the anti-tumour effect of progestin on mouse in vivo xenograft tumour.

CONCLUSIONS

Our findings suggest that TSLP enhances the sensitivity of EC to progestin through the BMP4/Smad5/AR/KANK1 axis, and provide a link between embryo development and cancer progress, paving the way for the establishment of novel strategy overcoming progestin resistance using embryo original factors.

E-cadherin variants associated with oral facial clefts trigger aberrant cell motility in a REG1A-dependent manner

BACKGROUND

Germline mutations of E-cadherin contribute to hereditary diffuse gastric cancer (HDGC) and congenital malformations, such as oral facial clefts (OFC). However, the molecular mechanisms through which E-cadherin loss-of-function triggers distinct clinical outcomes remain unknown. We postulate that E-cadherin-mediated disorders result from abnormal interactions with the extracellular matrix and consequent aberrant intracellular signalling, affecting the coordination of cell migration.

METHODS

Herein, we developed in vivo and in vitro models of E-cadherin mutants associated with either OFC or HDGC. Using a Drosophila approach, we addressed the impact of the different variants in cell morphology and migration ability. By combining gap closure migration assays and time-lapse microscopy, we further investigated the migration pattern of cells expressing OFC or HDGC variants. The adhesion profile of the variants was evaluated using high-throughput ECM arrays, whereas RNA sequencing technology was explored for identification of genes involved in aberrant cell motility.

RESULTS

We have demonstrated that cells expressing OFC variants exhibit an excessive motility performance and irregular leading edges, which prevent the coordinated movement of the epithelial monolayer. Importantly, we found that OFC variants promote cell adhesion to a wider variety of extracellular matrices than HDGC variants, suggesting higher plasticity in response to different microenvironments. We unveiled a distinct transcriptomic profile in the OFC setting and pinpointed REG1A as a putative regulator of this outcome. Consistent with this, specific RNAi-mediated inhibition of REG1A shifted the migration pattern of OFC expressing cells, leading to slower wound closure with coordinated leading edges.

CONCLUSIONS

We provide evidence that E-cadherin variants associated with OFC activate aberrant signalling pathways that support dynamic rearrangements of cells towards improved adaptability to the microenvironment. This proficiency results in abnormal tissue shaping and movement, possibly underlying the development of orofacial malformations.

Advancements in Genetic Marker Exploration for Livestock Vertebral Traits with a Focus on China

In livestock breeding, the number of vertebrae has gained significant attention due to its impact on carcass quality and quantity. Variations in vertebral traits have been observed across different animal species and breeds, with a strong correlation to growth and meat production. Furthermore, vertebral traits are classified as quantitative characteristics. Molecular marker techniques, such as marker-assisted selection (MAS), have emerged as efficient tools to identify genetic markers associated with vertebral traits. In the current review, we highlight some key potential genes and their polymorphisms that play pivotal roles in controlling vertebral traits (development, length, and number) in various livestock species, including pigs, donkeys, and sheep. Specific genetic variants within these genes have been linked to vertebral development, number, and length, offering valuable insights into the genetic mechanisms governing vertebral traits. This knowledge has significant implications for selective breeding strategies to enhance structural characteristics and meat quantity and quality in livestock, ultimately improving the efficiency and quality of the animal husbandry industry.

Signaling Pathways in Trans-differentiation of Mesenchymal Stem Cells: Recent Advances

Mesenchymal stem cells are a group of multipotent cells that can be induced to differentiate into other cell types. The cells fate is decided by various signaling pathways, growth factors, and transcription factors in differentiation. The proper coordination of these factors will result in cell specification. MSCs are capable of being differentiated into osteogenic, chondrogenic, and adipogenic lineages. Different conditions induces the MSCs into particular phenotypes. The MSC trans-differentiation ensues as a response to environmental factors or due to circumstances that prove to favor trans-differentiation. Depending on the stage at which they are expressed, and the genetic alterations they undergo prior to their expression, transcription factors can accelerate the process of trans-differentiation. Further research has been conducted on the challenging aspect of MSCs being developed into non-mesenchymal lineage. The cells that are differentiated in this way maintain their stability even after being induced in animals. The recent advancements in the trans-differentiation capacities of MSCs on induction with chemicals, growth inducers, improved differentiation mediums, growth factors from plant extracts, and electrical stimulation are discussed in this paper. Signaling pathways have a great effect on MSCs trans-differentiation and they need to be better understood for their applications in therapeutic techniques. So, this paper tends to review the major signaling pathways that play a vital role in the trans-differentiation of MSC.

Zizyphus mauritiana seed extract: Paving the way for next-generation bone constructs with nano-fluorohydroxyapatite/carboxymethyl chitosan nanocomposite scaffold

This is the first study that explored the potential use of Zizyphus mauritiana seed extract (ZSE) to synthesize nano-fluorohydroxyapatite/carboxymethyl chitosan nanocomposite scaffolds at different concentrations (CFZ1, CFZ2 and CFZ3) using co-precipitation method. The proposed scaffolds showed presence of intermolecular H bonding interactions between the constituents, according to the FTIR. The mechanical studies revealed shore hardness of 72 ± 4.6 and optimal compressive modulus in case of CFZ3 [1654.48 ± 1.6 MPa], that was comparable with that of human cortical bone. The SEM, TEM and platelet adhesion images corroborated uniformly distributed needle like particles in case of CFZ3 with an average size ranging from 22 to 26 nm, linked rough morphology, and appropriate hemocompatibility. The markedly up regulation in the ALP activity and protein adsorption upon increasing ZSE concentration demonstrated that CFZ nanocomposite scaffolds were compatible with osteoblastic cells relative to CF nanocomposite. The cytotoxicity study indicated that CFZ nanocomposite do not induce toxicity over MG-63 and did not aggravate LDH leakage in contrast to CF. The histopathological investigations on albino rats confirmed significantly improved regeneration of bone in the repair of a critical-size [8 mm] calvarium defect. Therefore, CFZ3 nanocomposite scaffold represents a simple, off-the-shelf solution to the combined challenges associated with bone defects.

Integrated Osteoinductive Factors─Exosome@MicroRNA-26a Hydrogel Enhances Bone Regeneration

MicroRNAs (miRNAs) are a new therapeutic tool that can target multiple genes by inducing translation repression and target mRNA degradation. Although miRNAs have gained significant attention in oncology and in work on genetic disorders and autoimmune diseases, their application in tissue regeneration remains hindered by several challenges, such as miRNA degradation. Here, we reported Exosome@MicroRNA-26a (Exo@miR-26a), an osteoinductive factor that can be substituted for routinely used growth factors, which was constructed using bone marrow stem cell (BMSC)-derived exosomes and microRNA-26a (miR-26a). Exo@miR-26a-integrated hydrogels significantly promoted bone regeneration when implanted into defect sites; as the exosome stimulated angiogenesis, miR-26a promoted osteogenesis while the hydrogel enabled a site-directed release. Moreover, BMSC-derived exosomes further facilitated healthy bone regeneration by repressing osteoclast differentiation-related genes rather than damaging osteoclasts. Taken together, our findings demonstrate the promising potential of Exo@miR-26a for bone regeneration and provide a new strategy for the application of miRNA therapy in tissue engineering.

Salmonella enhances osteogenic differentiation in adipose-derived mesenchymal stem cells

The potential of mesenchymal stem cells (MSCs) for tissue repair and regeneration has garnered great attention. While MSCs are likely to interact with microbes at sites of tissue damage and inflammation, like in the gastrointestinal system, the consequences of pathogenic association on MSC activities have yet to be elucidated. This study investigated the effects of pathogenic interaction on MSC trilineage differentiation paths and mechanisms using model intracellular pathogen Salmonella enterica ssp enterica serotype Typhimurium. The examination of key markers of differentiation, apoptosis, and immunomodulation demonstrated that Salmonella altered osteogenic and chondrogenic differentiation pathways in human and goat adipose-derived MSCs. Anti-apoptotic and pro-proliferative responses were also significantly upregulated (p &lt; 0.05) in MSCs during Salmonella challenge. These results together indicate that Salmonella, and potentially other pathogenic bacteria, can induce pathways that influence both apoptotic response and functional differentiation trajectories in MSCs, highlighting that microbes have a potentially significant role as influencers of MSC physiology and immune activity.

Bone circuitry and interorgan skeletal crosstalk

The past decade has seen significant advances in our understanding of skeletal homeostasis and the mechanisms that mediate the loss of bone integrity in disease. Recent breakthroughs have arisen mainly from identifying disease-causing mutations and modeling human bone disease in rodents, in essence, highlighting the integrative nature of skeletal physiology. It has become increasingly clear that bone cells, osteoblasts, osteoclasts, and osteocytes, communicate and regulate the fate of each other through RANK/RANKL/OPG, liver X receptors (LXRs), EphirinB2-EphB4 signaling, sphingolipids, and other membrane-associated proteins, such as semaphorins. Mounting evidence also showed that critical developmental pathways, namely, bone morphogenetic protein (BMP), NOTCH, and WNT, interact each other and play an important role in postnatal bone remodeling. The skeleton communicates not only with closely situated organs, such as bone marrow, muscle, and fat, but also with remote vital organs, such as the kidney, liver, and brain. The metabolic effect of bone-derived osteocalcin highlights a possible role of skeleton in energy homeostasis. Furthermore, studies using genetically modified rodent models disrupting the reciprocal relationship with tropic pituitary hormone and effector hormone have unraveled an independent role of pituitary hormone in skeletal remodeling beyond the role of regulating target endocrine glands. The cytokine-mediated skeletal actions and the evidence of local production of certain pituitary hormones by bone marrow-derived cells displays a unique endocrine-immune-skeletal connection. Here, we discuss recently elucidated mechanisms controlling the remodeling of bone, communication of bone cells with cells of other lineages, crosstalk between bone and vital organs, as well as opportunities for treating diseases of the skeleton.

Ecological Speciation Promoted by Divergent Regulation of Functional Genes Within African Cichlid Fishes

Rapid ecological speciation along depth gradients has taken place repeatedly in freshwater fishes, yet molecular mechanisms facilitating such diversification are typically unclear. In Lake Masoko, an African crater lake, the cichlid Astatotilapia calliptera has diverged into shallow-littoral and deep-benthic ecomorphs with strikingly different jaw structures within the last 1,000 years. Using genome-wide transcriptome data, we explore two major regulatory transcriptional mechanisms, expression and splicing-QTL variants, and examine their contributions to differential gene expression underpinning functional phenotypes. We identified 7,550 genes with significant differential expression between ecomorphs, of which 5.4% were regulated by cis-regulatory expression QTLs, and 9.2% were regulated by cis-regulatory splicing QTLs. We also found strong signals of divergent selection on differentially expressed genes associated with craniofacial development. These results suggest that large-scale transcriptome modification plays an important role during early-stage speciation. We conclude that regulatory variants are important targets of selection driving ecologically relevant divergence in gene expression during adaptive diversification.

Dynamic transcriptome changes during osteogenic differentiation of bone marrow-derived mesenchymal stem cells isolated from chicken

Osteoblasts are indispensable for skeletal growth and maintenance. Bone marrow-derived mesenchymal stem cells (BMSCs) are useful in studying osteogenesis. In this study, BMSCs isolated from White Leghorns were differentiated into osteoblasts in vitro. Cells induced for -1, 0, 1, 11, and 22 d were used for transcriptomic analyses using the HISAT2-Stringtie-DESeq2 pipeline. Weighted correlation network analysis was processed to investigate significant modules, including differentially expressed genes (DEGs), correlated with osteogenic differentiation. Gene ontology and pathway enrichment analyses of DEGs were performed to elucidate the mechanisms of osteoblast differentiation. A total of 534, 1,144, 1,077, and 337 DEGs were identified between cells induced for -1 and 0, 0 and 1, 1 and 11, and 11 and 22 d, respectively (|log2FC| > 1.0, FDR <0.05). DEGs were mainly enriched in pathways related to cell proliferation in the early stage of osteogenic differentiation and pathways, such as the TGF-β signaling pathway, in the middle and late stages of osteogenic differentiation. A protein–protein interaction network of the 87 DEGs in the MEturquoise module within top 5-%-degree value was built utilizing the STRING database. This study is the first to elucidate the transcriptomic changes in the osteogenic differentiation of BMSCs isolated from White Leghorns at different times. Our results provide insight into the dynamic transcriptome changes during BMSC differentiation into osteoblasts in chicken.

Full-length transcriptome and analysis of bmp-related genes in Platypharodon extremus

Platypharodon extremus is an endemic species on the Qinghai–Tibet Plateau. As a secondary protected species in China, the basic genomic information of this species has not yet been reported. Here, through third-generation sequencing, the full-length transcriptome of P. extremus was obtained. We identified 323,290 CCS sequences, and a total of 50,083 unigenes were extracted after correction with second-generation sequencing data and the removal of redundant reads. A total of 50,067 transcripts were annotated with the various databases. Based on the sequence information, three members in the bone morphogenetic proteins (bmps) family and their receptors, were identified. We found that the special structures of these proteins (zinc-dependent metalloproteinase domain, CUB domains, EGF-like domains and TGF-β domain) are highly conserved in fish and that they are closely evolutionarily related to the bmps and bmp receptors of Cyprinidae fishes. This is the first study to sequence the full-length transcriptome of P. extremus, which will help us to further understand its biology.

SUMOylation in Skeletal Development, Homeostasis, and Disease

The modification of proteins by small ubiquitin-related modifier (SUMO) molecules, SUMOylation, is a key post-translational modification involved in a variety of biological processes, such as chromosome organization, DNA replication and repair, transcription, nuclear transport, and cell signaling transduction. In recent years, emerging evidence has shown that SUMOylation regulates the development and homeostasis of the skeletal system, with its dysregulation causing skeletal diseases, suggesting that SUMOylation pathways may serve as a promising therapeutic target. In this review, we summarize the current understanding of the molecular mechanisms by which SUMOylation pathways regulate skeletal cells in physiological and disease contexts.

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.

Parental exposure to CdSe/ZnS QDs affects cartilage development in rare minnow (Gobiocypris rarus) offspring

Cartilage development is a sensitive process that is easily disturbed by environmental toxins. In this study, the toxicity of CdSe/ZnS quantum dots on the skeleton of the next generation (F1) was evaluated using rare minnows (Gobiocypris rarus) as model animals. Four-month-old sexually mature parental rare minnows (F0) were selected and treated with 0, 100, 200, 400 and 800 nmol/L CdSe/ZnS quantum dots for 4 days. Embryos of F1 generation rare minnows were obtained by artificial insemination. The results showed that with increasing maternal quantum dots exposure, the body length of F1 embryos decreased, the overall calcium content decreased, and the deformity and mortality rates increased. Alcian blue staining results showed that the lengths of the craniofacial mandible, mandibular arch length, mandibular width, and CH-CH and CH-PQ angles of larvae of rare minnows increased; histological hematoxylin-eosin staining further indicated that quantum dots affected the development of chondrocytes. Furthermore, high concentrations of CdSe/ZnS quantum dots inhibited the transcript expression of the bmp2b, bmp4, bmp6, runx2b, sox9a, lox1 and col2α1 genes. In conclusion, CdSe/ZnS quantum dots can affect the skeletal development of F1 generation embryos of rare minnows at both the individual and molecular levels, the damage to the craniofacial bone is more obvious, and the toxic effect of high concentrations of quantum dots (400 nmol/L and 800 nmol/L) is more significant.

A Comprehensive Overview of Globally Approved JAK Inhibitors

Janus kinase (JAK) is a family of cytoplasmic non-receptor tyrosine kinases that includes four members, namely JAK1, JAK2, JAK3, and TYK2. The JAKs transduce cytokine signaling through the JAK-STAT pathway, which regulates the transcription of several genes involved in inflammatory, immune, and cancer conditions. Targeting the JAK family kinases with small-molecule inhibitors has proved to be effective in the treatment of different types of diseases. In the current review, eleven of the JAK inhibitors that received approval for clinical use have been discussed. These drugs are abrocitinib, baricitinib, delgocitinib, fedratinib, filgotinib, oclacitinib, pacritinib, peficitinib, ruxolitinib, tofacitinib, and upadacitinib. The aim of the current review was to provide an integrated overview of the chemical and pharmacological data of the globally approved JAK inhibitors. The synthetic routes of the eleven drugs were described. In addition, their inhibitory activities against different kinases and their pharmacological uses have also been explained. Moreover, their crystal structures with different kinases were summarized, with a primary focus on their binding modes and interactions. The proposed metabolic pathways and metabolites of these drugs were also illustrated. To sum up, the data in the current review could help in the design of new JAK inhibitors with potential therapeutic benefits in inflammatory and autoimmune diseases.

Type VI collagen regulates endochondral ossification in the temporomandibular joint

For many years there has been a keen interest in developing regenerative treatment for temporomandibular joint–osteoarthritis (TMJ‐OA). Currently, there is no consensus treatment due to the limited self‐healing ability of articular cartilage and lack of understanding of the complex mechanisms regulating cartilage development in the TMJ. Endochondral ossification, the process of subchondral bone formation through chondrocyte differentiation, is critical for TMJ growth and development, and is tightly regulated by the composition of the extracellular matrix (ECM). Type VI collagen is a highly expressed ECM component in the TMJ cartilage, yet its specific functions are largely unknown. In this study, we investigated α2(VI)‐deficient (Col6a2‐knockout [KO]) mice, which are unable to secret or incorporate type VI collagen into their ECM. Compared with wild‐type (WT) mice, the TMJ condyles of Col6a2‐KO mice exhibit decreased bone volume/tissue volume (BV/TV) and a larger bone marrow space, suggesting the α2(VI)‐deficient condyles have a failure in endochondral ossification. Differentiating chondrocytes are the main source of bone cells during endochondral ossification. Our study shows there is an increased number of chondrocytes in the proliferative zone and decreased Col10‐expressing chondrocytes in Col6a2‐KO cartilage, all pointing to abnormal chondrocyte differentiation and maturation. In addition, RNA sequencing (RNAseq) analysis identified distinct gene expression profiles related to cell cycle and ECM organization that were altered in the mutant condyles. These data also suggest that bone morphogenetic protein 2 (BMP2) activity was deregulated during chondrocyte differentiation. Immunohistochemical analysis indicated an upregulation of Col2 and Acan expression in Col6a2‐KO cartilage. Moreover, the expression of pSmad1/5/8 and Runx2 was decreased in the Col6a2‐KO cartilage compared with WT controls. Taken together, our data indicate that type VI collagen expressed in the TMJ cartilage is important for endochondral ossification, possibly by modulating the ECM and altering/disrupting signaling pathways important for TMJ chondrocyte differentiation. Published 2022. This article is a U.S. Government work and is in the public domain in the USA. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Craniofacial Bone Tissue Engineering: Current Approaches and Potential Therapy

Craniofacial bone defects can result from various disorders, including congenital malformations, tumor resection, infection, severe trauma, and accidents. Successfully regenerating cranial defects is an integral step to restore craniofacial function. However, challenges managing and controlling new bone tissue formation remain. Current advances in tissue engineering and regenerative medicine use innovative techniques to address these challenges. The use of biomaterials, stromal cells, and growth factors have demonstrated promising outcomes in vitro and in vivo. Natural and synthetic bone grafts combined with Mesenchymal Stromal Cells (MSCs) and growth factors have shown encouraging results in regenerating critical-size cranial defects. One of prevalent growth factors is Bone Morphogenetic Protein-2 (BMP-2). BMP-2 is defined as a gold standard growth factor that enhances new bone formation in vitro and in vivo. Recently, emerging evidence suggested that Megakaryocytes (MKs), induced by Thrombopoietin (TPO), show an increase in osteoblast proliferation in vitro and bone mass in vivo. Furthermore, a co-culture study shows mature MKs enhance MSC survival rate while maintaining their phenotype. Therefore, MKs can provide an insight as a potential therapy offering a safe and effective approach to regenerating critical-size cranial defects.

Modern approaches on stem cells and scaffolding technology for osteogenic differentiation and regeneration

The process of bone repair has always been a natural mystery. Although bones do repair themselves, supplemental treatment is required for the initiation of the self-regeneration process. Predominantly, surgical procedures are employed for bone regeneration. Recently, cell-based therapy for bone regeneration has proven to be more effective than traditional methods, as it eliminates the immune risk and painful surgeries. In clinical trials, various stem cells, especially mesenchymal stem cells, have shown to be more efficient for the treatment of several bone-related diseases, such as non-union fracture, osteogenesis imperfecta, osteosarcoma, and osteoporosis. Furthermore, the stem cells grown in a suitable three-dimensional scaffold support were found to be more efficient for osteogenesis. It has been shown that the three-dimensional bioscaffolds support and simulate an in vivo environment, which helps in differentiation of stem cells into bone cells. Bone regeneration in patients with bone disorders can be improved through modification of stem cells with several osteogenic factors or using stem cells as carriers for osteogenic factors. In this review, we focused on the various types of stem cells and scaffolds that are being used for bone regeneration. In addition, the molecular mechanisms of various transcription factors, signaling pathways that support bone regeneration and the senescence of the stem cells, which limits bone regeneration, have been discussed.

Biomolecules Orchestrating Cardiovascular Calcification

Vascular calcification, once considered a degenerative, end-stage, and inevitable condition, is now recognized as a complex process regulated in a manner similar to skeletal bone at the molecular and cellular levels. Since the initial discovery of bone morphogenetic protein in calcified human atherosclerotic lesions, decades of research have now led to the recognition that the regulatory mechanisms and the biomolecules that control cardiovascular calcification overlap with those controlling skeletal mineralization. In this review, we focus on key biomolecules driving the ectopic calcification in the circulation and their regulation by metabolic, hormonal, and inflammatory stimuli. Although calcium deposits in the vessel wall introduce rupture stress at their edges facing applied tensile stress, they simultaneously reduce rupture stress at the orthogonal edges, leaving the net risk of plaque rupture and consequent cardiac events depending on local material strength. A clinically important consequence of the shared mechanisms between the vascular and bone tissues is that therapeutic agents designed to inhibit vascular calcification may adversely affect skeletal mineralization and vice versa. Thus, it is essential to consider both systems when developing therapeutic strategies.

Molecular Mechanisms of Chondrocyte Proliferation and Differentiation

Cartilage is a kind of connective tissue that buffers pressure and is essential to protect joint movement. It is difficult to self-recover once cartilage is damaged due to the lack of blood vessels, lymph, and nerve tissues. Repair of cartilage injury is mainly achieved by stimulating chondrocyte proliferation and extracellular matrix (ECM) synthesis. Cartilage homeostasis involves the regulation of multiple growth factors and the transduction of cellular signals. It is a very complicated process that has not been elucidated in detail. In this review, we summarized a variety of signaling molecules related to chondrocytes function. Especially, we described the correlation between chondrocyte-specific regulatory factors and cell signaling molecules. It has potential significance for guiding the treatment of cartilage injury.

Agaricus bisporus-Derived Glucosamine Hydrochloride Facilitates Skeletal Injury Repair through Bmp Signaling in Zebrafish Osteoporosis Model

Glucosamine hydrochloride (GAH), one of the most basic and important derivatives of chitin, is obtained by hydrolysis of chitin in concentrated hydrochloric acid. At present, little is known about how GAH functions in skeletal development. In this report, we demonstrate that GAH, extracted from the cell wall of Agaricus bisporus, acts in a dose-dependent manner to promote not only cartilage and bone development in larvae but also caudal fin regeneration in adult fish. Furthermore, GAH treatment causes a significant increase in expression of bone-related marker genes, indicating its important role in promoting skeletal development. We show that in both larval and adult osteoporosis models induced by high iron osteogenic defects are significantly ameliorated after treatment with GAH, which regulates expression of a series of bone-related genes. Finally, we demonstrate that GAH promotes skeletal development and injury repair through bone morphogenetic protein (Bmp) signaling, and it works at the downstream of the receptor level. Taken together, our findings not only provide a strong research foundation and strategy for the screening of natural osteoporosis drugs and product development using a zebrafish model but also establish the potential for the development of Agaricus bisporus-derived GAH as a new drug for osteoporosis treatment.

The Potential of FGF-2 in Craniofacial Bone Tissue Engineering: A Review

Bone is a hard-vascularized tissue, which renews itself continuously to adapt to the mechanical and metabolic demands of the body. The craniofacial area is prone to trauma and pathologies that often result in large bone damage, these leading to both aesthetic and functional complications for patients. The "gold standard" for treating these large defects is autologous bone grafting, which has some drawbacks including the requirement for a second surgical site with quantity of bone limitations, pain and other surgical complications. Indeed, tissue engineering combining a biomaterial with the appropriate cells and molecules of interest would allow a new therapeutic approach to treat large bone defects while avoiding complications associated with a second surgical site. This review first outlines the current knowledge of bone remodeling and the different signaling pathways involved seeking to improve our understanding of the roles of each to be able to stimulate or inhibit them. Secondly, it highlights the interesting characteristics of one growth factor in particular, FGF-2, and its role in bone homeostasis, before then analyzing its potential usefulness in craniofacial bone tissue engineering because of its proliferative, pro-angiogenic and pro-osteogenic effects depending on its spatial-temporal use, dose and mode of administration.

Stichopus japonicus Polysaccharide Stimulates Osteoblast Differentiation through Activation of the Bone Morphogenetic Protein Pathway in MC3T3-E1 Cells

This study aimed to examine the combined use of bone morphogenetic protein-2 (BMP-2) and polysaccharide isolated from Stichopus japonicus on osteogenic differentiation of MC3T3-E1 cells. Osteogenic differentiation was measured via histochemical staining of alkaline phosphatase (ALP) assay, alizarin red staining of mineralization assay, Western blotting, ELISA, and a qRT-PCR evaluation for the expression of BMP-2, runt-related transcription factor-2 (Runx-2), osteocalcin (OCN), osteopontin (OPN), and collagen type I (Col I) in MC3T3-E1 cells. Immunofluorescence assay was utilized to assess the BMP-2 localized on the cell surface. The results illustrated that SP-2 was able to increase ALP expression and accelerate the mineralization. Osteoblasts cultured on BMP-2/SP-2 substrate increased the expression levels of BMP-2, Runx-2, Col I, OCN, and OPN. SP-2 increased the binding efficiency involving a BMP-2 and its cell surface receptor. The dose of 5 μg/mL SP-2 used showed the best function of inducing osteoblast differentiation. These findings indicated that SP-2 is a more effective enhancer that cooperated with BMP-2 to induce osteoblastic differentiation by utilizing the BMP-2 signaling pathway.

Fabrication of Decellularized Engineered Extracellular Matrix through Bioreactor-Based Environment for Bone Tissue Engineering

Extracellular matrix (ECM)-contained grafts can be achieved by decellularization of native bones or synthetic scaffolds. Limitations associated with harvesting the native bone has raised interest in preparing in vitro ECM bioscaffold for bone tissue engineering. Here, we intend to develop an ECM-contained construct via decellularizing an engineered gelatin-coated β-tricalcium phosphate (gTCP) scaffold. In order to find an optimal protocol for decellularization of cell-loaded gTCP scaffolds, they were seeded with buccal fat pad-derived stem cells. Then, four decellularization protocols including sodium dodecyl sulfate, trypsin, Triton X-100, and combined solution methods were compared for the amounts of residual cells and remnant collagen and alteration of scaffold structure. Then, the efficacy of the selected protocol in removing cells from gTCP scaffolds incubated in a rotating and perfusion bioreactor for 24 days was evaluated and compared with static condition using histological analysis. Finally, decellularized scaffolds, reloaded with cells, and their cytotoxicity and osteoinductive capability were evaluated. Complete removal of cells from gTCP scaffolds was achieved from all protocols. However, treatment with Triton X-100 showed significantly higher amount of remnant ECM. Bioreactor-incubated scaffolds possessed greater magnitude of ECM proteins including collagen and glycosaminoglycans. Reseeding the decellularized scaffolds also represented higher osteoinductivity of bioreactor-based scaffolds. Application of Triton X-100 as decellularization protocol and usage of bioreactors are suggested as a suitable technique for designing ECM-contained grafts for bone tissue engineering.

Evaluation of Osteogenic/Cementogenic Modulating Potential of PAI-1 Transfected Media for Stem Cells

AIM OF THE STUDY

In vitro evaluation of the effects of plasminogen activator inhibitor-1 (PAI-1) transfected-conditioned media (P-CM) on the differentiation of human periodontal ligament stem cells (hPDLSCs) and human periapical follicular stem cells (hPAFSCs).

MATERIALS AND METHODS

The hPDLSCs and hPAFSCs received from impacted third molars were treated with P-CM and viability, as well as differentiation of the cells were evaluated. Plasmids were constructed according to standard techniques, and all sequences were validated by proper enzyme digestion and sequencing. Chinese hamster ovarian (CHO) cells were transfected with pcDNA3.1-hPAI-1 plasmid to obtain P-CM, followed by western blotting and PAI-1-specific ELISA kit to evaluate the proteins of P-CM. The cell viability of hPDLSCs and hPAFSCs were analyzed using MTT assay after 48 h of incubation. Alizarin red S staining was performed to evaluate the differentiation of hPDLSCs and hPAFSCs. The reverse transcription-polymerase chain reaction was used to observe the expression levels of osteogenic/cementogenic marker genes. The human cytokine antibody array was applied for further analysis of cytokine expression in P-CM.

RESULTS

P-CM significantly promoted the differentiation of hPDLSCs and hPAFSCs and upregulated the expression of osteogenic/cementogenic marker genes in vitro. Furthermore, rhPAI-1 promoted mineralized nodules formation of hPDLSCs and hPAFSCs, and we identified that other proteins, RANTES and IL-6, were highly expressed in P-CM.

CONCLUSIONS

P-CM promoted the differentiation of hPDLSCs and hPAFSCs by upregulating the expression of RANTES and IL-6, and interaction between PAI-1 and RANTES/IL-6 signaling may be involved in P-CM-induced osteogenic/cementogenic differentiation.

Toxic effects of dechlorane plus on the common carp (Cyprinus carpio) embryonic development

Dechlorane Plus (DP) is a widely used chlorinated flame retardant, which has been extensively detected in the environment. Although DP content in the surface water is low, it can pose a continuous exposure risk to aquatic organisms due to its strong bioaccumulation. Considering that the related studies on the toxicity mechanism of DP exposure are limited, the effect of DP on carp embryo development was evaluated. In the present work, carp embryos were exposed to different concentrations (0, 30, 60, and 120 μg/L) of DP at 3 h post-fertilization (hpf). The expression levels of neural and skeletal development-associated genes, such as sox2, sox19a, Mef2c and BMP4, were detected with quantitative PCR, and the changes in different developmental toxicity endpoints were observed. Our results demonstrated that the expression levels of sox2, sox19a, Mef2c and BMP4 were significantly altered and several developmental abnormalities were found in DP-exposed carp embryos, such as DNA damage, increased mortality rate, delayed hatching time, reduced hatching rate, decreased body length, and increased morphological deformities. In addition, the activities of reactive oxygen species and malondialdehyde were remarkably higher in 60 and 120 μg/L DP exposure groups than in control group. These results suggest that DP can exhibit a unique modes of action, which lead to aberration occurrence in the early development stage of common carps, which may be related to some gene damage and oxidative stress. Besides, the parameters evaluated here can be used as tools to access the environmental risk for biota and humans exposed to DP.

Effects of ginsenosides on bone remodelling for novel drug applications: a review

BACKGROUND

Ginsenosides are pharmacologically active compounds that are often extracted from the Panax plant for their medicinal properties. Ginsenosides have multiple effects, including antitumor effects which have been widely studied. In recent years, studies have found that ginsenosides promote proliferation and osteogenesis of osteoblast-related cells, as well as inhibit the activity of osteoclasts.

MAIN BODY

We briefly introduces the molecules and BMP, WNT, and RANKL signalling pathways involved in bone formation and bone resorption. Next, recent studies on the mechanism of action of ginsenosides in bone remodelling are reviewed from three perspectives: the effects on proliferation of osteoblast-related cells, effects on osteogenesis and effects on osteoclasts. To expedite the development of drugs containing ginsenosides, we summarize the multiple beneficial roles of various types of ginsenosides in bone remodelling; including the promotion of bone formation, inhibition of bone resorption, and anti-inflammatory and antioxidant effects.

CONCLUSION

Many ginsenosides can promote bone formation and inhibit bone resorption, such as Rb1, Rb2 and Re. Ginsenosides have the potential to be new drugs for the treatment of osteoporosis, promote fracture healing and are strong candidates for cytokines in the tissue-engineered bone. This review provides a theoretical basis for clinical drug applications and proposes several future directions for exploring the beneficial role of ginseng compounds in bone remodelling.

Regulation of mesenchymal stem cell differentiation on microstructured titanium surfaces by semaphorin 3A

Peri-implant bone formation depends on the ability of mesenchymal stem cells (MSCs) to colonize implant surfaces and differentiate into osteoblasts, but the precise mechanisms controlling this process remain unclear. In vitro, MSCs undergo osteoblastic differentiation on microstructured titanium (Ti) surfaces in the absence of exogenous media supplements and produce factors that promote osteogenesis while regulating osteoclast activity, including semaphorins. The goal of this study was to evaluate the role of semaphorin 3A (Sema3A) on surface-mediated osteoblastic differentiation and determine the hierarchy of this signaling cascade. Human MSCs were cultured on 15 mm grade 2 smooth (pretreatment, PT), hydrophobic-microrough (sand blasted/acid etched, SLA), hydrophilic-microrough Ti (mSLA) (Institut Straumann AG, Basel, Switzerland), or tissue culture polystyrene (TCPS). Expression of SEMA3A family proteins increased after 7 days of culture, and the increased expression in response to microstructured Ti was dependent on recognition of the surface by integrin α2β1. Exogenous Sema3A increased differentiation whereas differentiation was decreased in cells treated with a Sema3A antibody. Furthermore, Sema3A influenced the production of osteoprotegerin and osteopontin suggesting it as an important local regulator of bone remodeling. Inhibition of Wnt3A and Wnt5A revealed that activation of Sema3A occurs downstream of Wnt5A and may facilitate the translocation of β-catenin bypassing the canonical Wnt3A initiating signal associated with osteoblastic differentiation. Furthermore, chemical inhibition of calmodulin (CaM), Ca²⁺/calmodulin-dependent protein kinase (CaMKII), phospholipase A₂ (PLA2), protein kinase C (PKC), and BMP receptors suggest that Sema3A could serve as a feedback mechanism for both Wnt5A and BMP2. Here, we show novel roles for Sema3A family proteins in the surface-dependent modulation of MSCs as well as important interactions with pathways known to be associated with osteoblastic differentiation. Moreover, their effects on bone remodeling markers have significant implications for peri-implant bone remodeling and downstream modulation of osteoclastic activity. These results suggest that Sema3A aids in peri-implant bone formation through regulation on multiple stages of osseointegration, making it a potential target to promote osseointegration in patients with compromised bone remodeling.

MnTBAP inhibits bone loss in ovariectomized rats by reducing mitochondrial oxidative stress in osteoblasts

The development of postmenopausal osteoporosis is thought to be closely related to oxidative stress. Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP), a novel superoxide dismutase (SOD) mimetic, could protect osteoblasts from cytotoxicity and dysfunction caused by oxidative stress. However, it is still unclear whether MnTBAP has effect on the development of postmenopausal osteoporosis. Here, we demonstrated that MnTBAP can inhibit bone mass loss and bone microarchitecture alteration, and increase the number of osteoblasts while reducing osteoclasts number, as well as improve the BMP-2 expression level in ovariectomized rat model. Additionally, MnTBAP can also prevent oxidative stress status up-regulation induced by ovariotomy and hydrogen peroxide (H₂O₂). Furthermore, MnTBAP reduced the effect of oxidative stress on osteoblasts differentiation and increased BMP-2 expression levels with a dose-dependent manner, via reducing the levels of mitochondrial oxidative stress in osteoblasts. Taken together, our findings provide new insights that MnTBAP inhibits bone loss in ovariectomized rats by reducing mitochondrial oxidative stress in osteoblasts, and maybe a potential drug in postmenopausal osteoporosis therapy.

The Morphology of Cross-Beaks and BMP4 Gene Expression in Huiyang Bearded Chickens

Simple Summary

Recently, the emergence of cross-beaks has been reported in several domestic chickens. Despite several candidate genes, bone morphogenetic protein 4 (BMP4) has been suggested as responsible for chicken cross-beaks. The subtypes of the morphology term, etiopathogenesis, and the relationship of the candidate BMP4 gene to cross-beaks are not yet known. The objective of this study was to describe the subtypes of cross-beaks by left or right and upper and lower jaw bones and to figure out the relationship between BMP4 and the development of craniofacial bones in Huiyang bearded chickens.

Abstract

Bird beaks are important for biological purposes such as food intake, removing parasites, and defining phenotypic attributes. Cross-beaks are a threat to poultry health and are harmful to productivity, wasting some units in the poultry industry. However, there is still limited research on subtypes of cross-beaks and the genetic basis of cross-beaks as well. Here, we described the subtypes of cross-beaks in terms of left or right and upper or lower jaw bones. We evaluated the impact of cross-beaks on craniofacial bones and figured out the relationship between bone morphogenetic protein 4 (BMP4) and the development of craniofacial bones in Huiyang bearded chickens. We identified five typical subtypes of cross-beaks by morphological assessment and X-ray scanning. We found that cross-beaks caused certain changes in the facial bone morphology, including changes to the length and width of the bone around the ocular area (p < 0.05). The relative expressions of BMP4 in lacrimal, mandible, premaxilla, frontal, and parietal bones were significantly higher in the severe cross-beak group, followed by that of the medium cross-beak group, weak cross-beak group, and control group (p < 0.05). Overall, we constructed a generally applicable method to classify cross-beaks in term of the angle. The skeleton around the ocular area was affected by the cross-beak. The expression levels of BMP4 in craniofacial bones may provide insight to potential role of BMP4 in the development of cross-beaks.

Accentuated osseointegration in osteogenic nanofibrous coated titanium implants

Anchoring of endosseous implant through osseointegration continues to be an important clinical need. Here, we describe the development of superior endosseous implant demonstrating enhance osseointegration, achieved through surface modification via coating of osteogenic nanofibres. The randomized bio-composite osteogenic nanofibres incorporating polycaprolactone, gelatin, hydroxyapatite, dexamethasone, beta-glycerophosphate and ascorbic acid were electrospun on titanium implants mimicking bone extracellular matrix and subsequently induced osteogenesis by targeting undifferentiated mesenchymal stem cells present in the peri-implant niche to regenerate osseous tissue. In proof-of-concept experiment on rabbit study models (n = 6), micro-computed tomography (Micro-CT), histomorphometric analysis and biomechanical testing in relation to our novel osteogenic nanofibrous coated implants showed improved results when compared to uncoated controls. Further, no pathological changes were detected during gross examination and necropsy on peri-implant osseous tissues regenerated in response to such coated implants. The findings of the present study confirm that osteogenic nanofibrous coating significantly increases the magnitude of osteogenesis in the peri-implant zone and favours the dynamics of osseointegration.

Glucocorticoid Enhanced the Expression of Ski in Osteonecrosis of Femoral Head: The Effect on Adipogenesis of Rabbit BMSCs

Glucocorticoid (GC)-induced osteonecrosis has been considered as the most serious side effect in long-term or over-dose steroid therapy. The decreased bone mass and increased marrow fat tissue demonstrated that GC can destroy the normal differentiation of bone marrow mesenchymal stem cells (BMSCs), which accelerates adipogenesis but not osteogenesis. However, the underlying mechanisms are still unclear. Ski, an evolutionary conserved protein, is a multifunctional transcriptional regulator that involved in regulating signaling pathways associated with adipogenesis differentiation, but the concrete function remains unclear. In this work, we first established a methylprednisolone (MPS)-induced osteonecrosis of femoral head (ONFH) rabbit model, in which the expression of Ski, PPAR-γ, and FABP4 was up-regulated compared with control group, and then we induced the isolated BMSCs from rabbit with dexamethasone (Dex) in vitro and the results showed that the Ski expression was up-regulated by Dex in a dose- and time-dependent manner. Therefore, we demonstrated that the expression of Ski was up-regulated in glucocorticoid-related osteonecrosis disease in vivo and in vitro. Moreover, the adipogenesis differentiation capacity of BMSCs was enhanced after induced by Dex, which was identified by Oil Red O staining, and the up-regulated PPAR-γ and FABP4 expression. To further study the function of Ski in BMSC after induced by Dex, Ski specific small interfering RNA (Ski-siRNA) was used. Results showed that knockdown of Ski obviously decreased adipogenesis differentiation evident by Oil Red O staining, and the expression of PPAR-γ and FABP4 was down-regulated simultaneously. Collectively, our findings suggest that Ski increased significantly during glucocorticoid-induced adipogenic differentiation of BMSCs, and the expression level was consistent with adipogenic-related proteins including PPAR-γ and FABP4. Based on the above data, we believe that Ski might become a new molecule in the treatment of GC-induced ONFH and our study could provide a basis for further study on the detailed function of Ski in ONFH.

Bile acids and bilirubin effects on osteoblastic gene profile. Implications in the pathogenesis of osteoporosis in liver diseases

Osteoporosis in advanced cholestatic and end-stage liver disease is related to low bone formation. Previous studies have demonstrated the deleterious consequences of lithocholic acid (LCA) and bilirubin on osteoblastic cells. These effects are partially or completely neutralized by ursodeoxycholic acid (UDCA). We have assessed the differential gene expression of osteoblastic cells under different culture conditions. The experiments were performed in human osteosarcoma cells (Saos-2) cultured with LCA (10 μM), bilirubin (50 μM) or UDCA (10 and 100 μM) at 2 and 24 h. Expression of 87 genes related to bone metabolism and other signalling pathways were assessed by TaqMan micro fluidic cards. Several genes were up-regulated by LCA, most of them pro-apoptotic (BAX, BCL10, BCL2L13, BCL2L14), but also MGP (matrix Gla protein), BGLAP (osteocalcin), SPP1 (osteopontin) and CYP24A1, and down-regulated bone morphogenic protein genes (BMP3 and BMP4) and DKK1 (Dickkopf-related protein 1). Parallel effects were observed with bilirubin, which up-regulated apoptotic genes and CSF2 (colony-stimulating factor 2) and down-regulated antiapoptotic genes (BCL2 and BCL2L1), BMP3, BMP4 and RUNX2. UDCA 100 μM had specific consequences since differential expression was observed, up-regulating BMP2, BMP4, BMP7, CALCR (calcitonin receptor), SPOCK3 (osteonectin), BGLAP (osteocalcin) and SPP1 (osteopontin), and down-regulating pro-apoptotic genes. Furthermore, most of the differential expression changes induced by both LCA and bilirubin were partially or completely neutralized by UDCA. Conclusion: Our observations reveal novel target genes, whose regulation by retained substances of cholestasis may provide additional insights into the pathogenesis of osteoporosis in cholestatic and end-stage liver diseases.

A combination insecticide at sub-lethal dose debilitated the expression pattern of crucial signalling molecules that facilitate craniofacial patterning in domestic chick Gallus domesticus

Pesticides despite being agents that protect the plants and humans from noxious pests, are infamous for their potential to cause detrimental health issues in nontargeted species. In order to ascertain the latter, a set of experiments were conducted by exposing early chick embryos to a widely used combination insecticide (Ci, 50% chlorpyrifos and 5% cypermethrin). The results revealed a myriad of congenital defects pertaining to craniofacial development such as anophthalmia, microphthalmia, exencephaly as well as deformed beak and cranial structures. These teratological manifestations could be attributed to the Ci induced alteration in the titre of major regulators of neurulation and ossification. Therefore, the mRNA and/or the protein level expression pattern of genes which are reported to be involved in the craniofacial development were studied at selected time points of embryonic development. The analysis of the result showed that there have been significant alternations in the expression patterns of the signalling molecules such as SHH, WNTs, CDH1, CDH2, L1CAM, PAX6, HOX, PCNA, GLI3, BMP7, FGF8, GLIs, SOX9, RUNX2, DLX5, COL10A1, CASPASE3 etc. on embryonic days 2, 4 and/or 10. Concurrently, on day 10, whole-mount skeletal staining and biochemical estimation of hydroxyproline were carried out in the cranial tissues of the embryos. The overall result of the current study indicates that exposure to Ci during early development impede the crucial regulatory signals that orchestrate the morphogenesis of cranial neural crest cells thereby hindering the normal progression of neural tube and endochondral ossification which collectively lead to craniofacial dysmorphism in domestic chicks.

Nano-Hydroxyapatite Coating Promotes Porous Calcium Phosphate Ceramic-Induced Osteogenesis Via BMP/Smad Signaling Pathway

BACKGROUND

The hierarchical porous structure and surface topography of calcium phosphate (CaP) bioceramics have a crucial impact on their osteoinductivity.

PURPOSE

To fabricate a biomimetic bone graft with an interconnected porous structure analogous to that of trabecular bone and a bioactive nanostructured surface with excellent osteoinductive potential.

MATERIALS AND METHODS

A biphasic CaP (BCP) substrate with highly porous structure was fabricated by an improved sponge replication method. Surface modification was performed by uniformly depositing a hydroxyapatite (HA) nanoparticle layer to create nHA-coated BCP scaffolds. The effects of these scaffolds on osteogenic differentiation of murine bone marrow-derived stem cells (BMSCs) were investigated in vitro, and their osteoinductivity was further assessed in vivo.

RESULTS

The BCP and nHA-coated BCP scaffolds had similar trabecular bone-like architectures but different surface structures, with mean grain sizes of ~55 nm and ~1 μm, respectively. Compared with the BCP substrate, the nHA-coated BCP scaffolds favored cell adhesion and promoted osteogenic differentiation of BMSCs, as evidenced by upregulated expression of osteogenic genes, enhanced alkaline phosphatase activity, and increased osteocalcin production. This could be attributed to activation of the BMP/Smad signaling pathway, as significantly higher expression levels of BMPRI, Smad1, Smad4, and Smad5 were observed in the nHA-coated BCP group. The nHA-coated BCP scaffold not only maintained scaffold integrity but also induced ectopic bone formation when implanted into rabbit dorsal muscle in vivo for 90 days, whereas the BCP substrate underwent marked biodegradation that led to severe inflammation with no sign of osteogenesis.

CONCLUSION

The present study demonstrates the potential of this biomimetic bone graft with a trabecular framework and nanotopography for use in orthopedic applications.

Phlorofucofuroeckol A from Edible Brown Alga Ecklonia Cava Enhances Osteoblastogenesis in Bone Marrow-Derived Human Mesenchymal Stem Cells

The deterioration of bone formation is a leading cause of age-related bone disorders. Lack of bone formation is induced by decreased osteoblastogenesis. In this study, osteoblastogenesis promoting effects of algal phlorotannin, phlorofucofuroeckol A (PFF-A), were evaluated. PFF-A was isolated from brown alga Ecklonia cava. The ability of PFF-A to enhance osteoblast differentiation was observed in murine pre-osteoblast cell line MC3T3-E1 and human bone marrow-derived mesenchymal stem cells (huBM-MSCs). Proliferation and alkaline phosphatase (ALP) activity of osteoblasts during differentiation was assayed following PFF-A treatment along extracellular mineralization. In addition, effect of PFF-A on osteoblast maturation pathways such as Runx2 and Smads was analyzed. Treatment of PFF-A was able to enhance the proliferation of differentiating osteoblasts. Also, ALP activity was observed to be increased. Osteoblasts showed increased extracellular mineralization, observed by Alizarin Red staining, following PFF-A treatment. In addition, expression levels of critical proteins in osteoblastogenesis such as ALP, bone morphogenetic protein-2 (BMP-2), osteocalcin and β-catenin were stimulated after the introduction of PFF-A. In conclusion, PFF-A was suggested to be a potential natural product with osteoblastogenesis enhancing effects which can be utilized against bone-remodeling imbalances and osteoporosis-related complications.

Carbon black-induced detrimental effect on osteoblasts at low concentrations: Remarkably compromised differentiation without significant cytotoxicity

Due to similar aerodynamic and micro-nano sized properties between airborne particles and synthetic nanoparticles, a large number of studies have been conducted using carbon-based particles, such as carbon black (CB), carbon nanotubes and graphite, in order to achieve deeper understandings of their adverse effects on human health. It has been reported that particulate matters can aggravate morbidity of patients suffering from bone and joint diseases, e.g. arthritis. However, the molecular mechanism is still elusive thus far. Under this context, we employed two cell lines of osteoblasts, MC3T3-E1 and MG-63, upon exposure to 4 different CB samples with differential physicochemical properties in research of mechanistic insights. Our results indicated that the carbon/oxygen ratio differed in these 4 CB materials showing the order: SB4A < Printex U < C1864 < C824455. In stark contrast, their cytotoxicity and capacity to trigger reactive oxygen species (ROS) in MC3T3-E1 and MG-63 cells closely correlated to oxygen content, revealing the reverse order: SB4A < Printex U < C1864 < C824455. It would be reasonable to speculate that ROS production was a predominant cause of CB cytotoxicity, which strongly relied on the oxygen content of CB. Our study further manifested that all CB samples even at low concentrations significantly inhibited osteoblast differentiation, as reflected by remarkably reduced activity of alkaline phosphatase (ALP) and compromised expression of the differentiation-related genes. And the inhibition on osteoblast differentiation also closely correlated to oxygen content of CB samples. Taken together, our combined data recognized oxygen-associated toxicity towards osteoblasts for CBs. More importantly, we uncovered a new adverse effect of CB exposure: suppression on osteoblast differentiation, which has been overlooked in the past.

A coupled reaction-diffusion-strain model predicts cranial vault formation in development and disease

How cells utilize instructions provided by genes and integrate mechanical forces generated by tissue growth to produce morphology is a fundamental question of biology. Dermal bones of the vertebrate cranial vault are formed through the direct differentiation of mesenchymal cells on the neural surface into osteoblasts through intramembranous ossification. Here we join a self-organizing Turing mechanism, computational biomechanics, and experimental data to produce a 3D representative model of the growing cerebral surface, cranial vault bones, and sutures. We show how changes in single parameters regulating signaling during osteoblast differentiation and bone formation may explain cranial vault shape variation in craniofacial disorders. A key result is that toggling a parameter in our model results in closure of a cranial vault suture, an event that occurred during evolution of the cranial vault and that occurs in craniofacial disorders. Our approach provides an initial and important step toward integrating biomechanics into the genotype phenotype map to explain the production of variation in head morphology by developmental mechanisms.

BMP4 mutations in tooth agenesis and low bone mass

OBJECTIVE

To identify an uncommon genetic cause of tooth agenesis (TA) by utilizing whole exome sequencing (WES) and targeted Sanger sequencing in a cohort of 120 patients with isolated TA.

DESIGN

One deleterious mutation in the gene encoding bone morphogenetic protein 4 (BMP4) was identified in 6 unrelated patients with TA by WES. After that, the coding exons of BMP4 were examined in 114 TA patients using Sanger sequencing. Dual-energy X-ray absorptiometry (DEXA) was used to measure the bone mineral density of patients who carried a BMP4 mutation. Finally, preliminary functional studies of two BMP4 mutants were performed.

RESULTS

We detected 3 novel missense mutations (c.58 G > A: p.Gly20Ser, c.326 G > T: p.Arg109Leu and c.614 T > C: p.Val205Ala) and 1 reported mutation in the BMP4 gene among 120 TA probands. The previously reported BMP4 mutation (c.751C > T: p.His251Tyr) was associated with urethra and eye anomalies. By extending the pedigrees, we determined that the tooth phenotypes had an autosomal dominant inheritance pattern, as individuals carrying a BMP4 mutation exhibit different types of dental anomalies. Interestingly, we observed that patients harboring a BMP4 mutation manifested early onset osteopenia or osteoporosis. Further in vitro functional assays demonstrated that two BMP4 mutants resulted in a decreased activation of Smad signaling. Therefore, a loss-of-function in BMP4 may contribute to the clinical phenotypes seen in this study.

CONCLUSIONS

We identified 4 mutations in the BMP4 gene in 120 TA patients. To our knowledge, this is the first study to describe human skeletal diseases associated with BMP4 mutations.

Developmental toxicity by thifluzamide in zebrafish (Danio rerio): Involvement of leptin

Although previous trials have indicated that thifluzamide induces developmental inhibition in zebrafish, understanding the distinct mechanism of thifluzamide in this process remains challenging. This study investigated the effect of thifluzamide on zebrafish development and the underlying related signaling pathway. Thifluzamide repressed glucagon (GC) levels but increased growth hormone (GH) levels, and changed the expression of the genes related to growth and development. Additionally, protein kinase A (PKA) and leptin levels were obviously decreased in zebrafish after exposure to thifluzamide for 28 days, but the phosphorylation of cAMP responsive element-binding protein (CREB) was increased. Our results suggested that the anti-developmental effects of thifluzamide in zebrafish are largely associated with alterations in expressions of genes related to growth and development through modulation of leptin.