The Function of Twisted Gastrulation in Regulating Osteoclast Differentiation is Dependent on BMP Binding

Multifaceted Functions of TWSG1: From Embryogenesis to Cancer Development

Bone morphogenetic proteins (BMPs) play an important role in development. Twisted gastrulation BMP signaling modulator 1 (TWSG1) was initially identified as a regulator of the dorsoventral axis formation in Drosophila. The mechanism of BMP signaling modulation by TWSG1 is complex. TWSG1 inhibits BMP signaling by binding to BMP ligands including BMP4, whereas it enhances signaling by interacting with Chordin, a BMP antagonist. Therefore, TWSG1 can act as both a BMP agonist and antagonist. TWSG1 has various functions ranging from embryogenesis to cancer progression. TWSG1 knockout mice showed neural, craniofacial, and mammary defects. TWSG1 also regulated erythropoiesis and thymocyte development. Furthermore, the relationship between TWSG1 and cancer has been elucidated. Allelic loss of TWSG1 was detected in colorectal cancer. TWSG1 expression was upregulated in papillary thyroid carcinoma and glioblastoma but downregulated in gastric and endometrial cancers. TWSG1 suppressed BMP7-enhanced sphere formation and migration in endometrial cancer cells, indicating its tumor-suppressive role. Further studies are required to clarify the TWSG1 function and its association with BMP signaling in cancer development. Finally, TWSG1 is abundantly expressed in human and mouse ovaries and sustains follicular growth in rodent ovaries. Thus, TWSG1 has various functions ranging from fertility to cancer. Therefore, TWSG1 signaling modulation may be beneficial in treating specific diseases such as cancer.

The Role of BMP Signaling in Osteoclast Regulation

The osteogenic effects of Bone Morphogenetic Proteins (BMPs) were delineated in 1965 when Urist et al. showed that BMPs could induce ectopic bone formation. In subsequent decades, the effects of BMPs on bone formation and maintenance were established. BMPs induce proliferation in osteoprogenitor cells and increase mineralization activity in osteoblasts. The role of BMPs in bone homeostasis and repair led to the approval of BMP2 by the Federal Drug Administration (FDA) for anterior lumbar interbody fusion (ALIF) to increase the bone formation in the treated area. However, the use of BMP2 for treatment of degenerative bone diseases such as osteoporosis is still uncertain as patients treated with BMP2 results in the stimulation of not only osteoblast mineralization, but also osteoclast absorption, leading to early bone graft subsidence. The increase in absorption activity is the result of direct stimulation of osteoclasts by BMP2 working synergistically with the RANK signaling pathway. The dual effect of BMPs on bone resorption and mineralization highlights the essential role of BMP-signaling in bone homeostasis, making it a putative therapeutic target for diseases like osteoporosis. Before the BMP pathway can be utilized in the treatment of osteoporosis a better understanding of how BMP-signaling regulates osteoclasts must be established.

Twisted gastrulation signaling modulator 1 promotes the ability of glioma cell through activating Akt pathway

Glioblastoma is one of the most common primary nervous system tumors and has a high mortality rate. It is necessary to explore a novel biological target and treatment approach. Twisted gastrulation signaling modulator 1 (TWSG1) is expressed in many tumors and closely related to tumor growth and proliferation. However, there is almost no report about the mechanism of TWSG1 in glioma. We used a glioma chip to detect the expression level of TWSG1 by Immunohistochemistry. The overexpression and silence experiments of TWSG1 were performed to assay the biological function of TWSG1 in LN229 and U251 cells. Subcutaneous xenograft mouse model presented the effect of TWSG1 expression on the malignant behavior of tumor cells. Experimental results displayed that the expression level for TWSG1 was substantially elevated in gliomas compared to that in normal brain tissue. The expression knockdown of TWSG1 caused inhibition of glioma cell proliferation. Besides, TWSG1 overexpression enhanced proliferation in glioma cells, and the capacity of proliferation was partly abolished by the PI3K inhibitor LY294002. We found that TWSG1 affected the activity of Akt signaling pathway. In conclusion, TWSG1 is overexpressed in glioma tissue and promotes tumor proliferation through Akt signaling pathway, may serve as a potential target for glioma diagnosis and therapy.

The Bone Morphogenetic Protein Pathway: The Osteoclastic Perspective

Bone health crucially relies on constant bone remodeling and bone regeneration, both tightly controlled processes requiring bone formation and bone resorption. Plenty of evidence identifies bone morphogenetic proteins (BMP) as major players in osteoblast differentiation and thus, bone formation. However, in recent past years, researchers also increasingly reported on the pivotal role of these multi-functional growth factors in osteoclast formation and activity. This review aims to summarize the current knowledge of BMP signaling within the osteoclast lineage, its role in bone resorption, and osteoblast-osteoclast coupling. Furthermore, subsequent clinical implications for recombinant BMP therapy will be discussed in view of recent preclinical and clinical studies.

Immediate reconstruction of mandibular defect after treatment of medication-related osteonecrosis of the jaw (MRONJ) with rhBMP-2/ACS and miniplate: Review of 3 cases

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The pathogenesis of MRONJ is related to repression of osteoclast mediated bone remodeling.

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rhBMP-2 can stimulate not only osteoblasts but also osteoclasts and induce new bone formation.

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ACS has been proved to be a good carrier of rhBMP-2 with maximal efficacy.

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Application of rhBMP-2/ACS can be a new approach to surgical treatment for MRONJ patients.

Introduction

The purpose of this study was to pursue, and to report the results of, mandibular reconstruction and rehabilitation of medication-related osteonecrosis of the jaw (MRONJ) patients having large critical-sized defects of the mandible using a combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) and absorbable collagen sponge (ACS) with surgical miniplate without any grafting materials.

Case presentation

Three (3) patients aged 67 and 86 (2 patients) presented due to discomfort on the mandible. They all had a medical history of bisphosphonate and steroids treatment orally or intravenously, and all had been diagnosed as MRONJ stage 3. Sequestrectomy and saucerization were performed, and then a surgical miniplate (Hansolmedical, Korea) was adapted and fixed on the sound portion of the mandible. rhBMP-2 was loaded onto an ACS at a dose of 1.5 mg/cc. Several rhBMP-2 (Cowellmedi, Korea)/ACS (Ateloplug, TRMkorea, Korea) were placed into the bony defect with a surgical miniplate. All 3 patients recovered without complications. They all exhibited radiographic evidence of bone formation by 3 months postoperatively in every case.

Conclusions

All 3 patients were treated successfully with rhBMP-2/ACS and miniplate without any complications. This protocol reported herein represents a new approach to the surgical treatment of maxillofacial bone defects and deficiencies, especially in MRONJ patients.

Differential Proteomic Analysis Predicts Appropriate Applications for the Secretome of Adipose-Derived Mesenchymal Stem/Stromal Cells and Dermal Fibroblasts

The adult stem cell secretome is currently under investigation as an alternative to cell-based therapy in regenerative medicine, thanks to the remarkable translational opportunity and the advantages in terms of handling and safety. In this perspective, we recently demonstrated the efficient performance of the adipose-derived mesenchymal stem/stromal cell (ASC) secretome in contrasting neuroinflammation in a murine model of diabetic neuropathy, where the administration of factors released by dermal fibroblasts (DFs) did not exert any effect. Up to now, the complex mixture of the constituents of the conditioned medium from ASCs has not been fully deepened, although its appropriate characterization is required in the perspective of a clinical use. Herein, we propose the differential proteomic approach for the identification of the players accounting for the functional effects of the cell secretome with the aim to unravel its appropriate applications. Out of 967 quantified proteins, 34 and 62 factors were found preponderantly or exclusively secreted by ASCs and DFs, respectively. This approach led to the recognition of distinct functions related to the conditioned medium of ASCs and DFs, with the former being involved in the regulation of neuronal death and apoptosis and the latter in bone metabolism and ossification. The proosteogenic effect of DF secretome was validated in vitro on human primary osteoblasts, providing a proof of concept of its osteoinductive potential. Besides discovering new applications of the cell type-specific secretome, the proposed strategy could allow the recognition of the cocktail of bioactive factors which might be responsible for the effects of conditioned media, thus providing a solid rationale to the implementation of a cell-free approach in several clinical scenarios involving tissue regeneration.

Transcriptomic hallmarks of bone remodelling revealed by RNA-Seq profiling in blood of Arabian horses during racing training regime

The impact of exercises on young developing organisms is still of interest to researchers. Similarly like Thoroughbreds, Arabian horses competing at the race track. The high percent of lameness and loss of days in training are often the result of weakness in the condition of the musculoskeletal system. The objective of the presented study was to identify by RNA-Seq method, the possible skeletal system originating transcriptomic profile in peripheral blood of Arabian horses undergoing race training. Obtained results showed that one of the most significantly deregulated pathway involved in bone homeostasis was those involved in osteoclast differentiation. Among the significantly expressed molecules, we recognized twelve genes potentially involved in the metabolism of the skeletal system: BGLAP, CTSK, TYROBP, PDLIM7, SLC9B2, TWSG1, NOTCH2, IL6ST, VAV3, NFATc1, CLEC5A, TXLNG. The panel of identified genes should be evaluated as candidate biomarkers for bone homeostasis indicators of Arabians performing on race tracks to assess bone remodelling states during training for race track competitions.

Genotype-Phenotype Analysis, Neuropsychological Assessment, and Growth Hormone Response in a Patient with 18p Deletion Syndrome

18p deletion syndrome is a rare chromosomal disease caused by deletion of the short arm of chromosome 18. By using cytogenetic and SNP array analysis, we identified a girl with 18p deletion syndrome exhibiting craniofacial anomalies, intellectual disability, and short stature. G-banding analysis of metaphase cells revealed an abnormal karyotype 46,XX,del(18)(p10). Further, SNP array detected a 15.3-Mb deletion at 18p11.21p11.32 (chr18:12842-15375878) including 61 OMIM genes. Genotype-phenotype correlation analysis showed that clinical manifestations of the patient were correlated with LAMA1, TWSG1, and GNAL deletions. Her neuropsychological assessment test demonstrated delay in most cognitive functions including impaired mathematics, linguistic skills, visual motor perception, respond speed, and executive function. Meanwhile, her integrated visual and auditory continuous performance test (IVA-CPT) indicated a severe comprehensive attention deficit. At age 7 and 1/12 years, her height was 110.8 cm (-2.5 SD height for age). Growth hormone (GH) treatment was initiated. After 27 months treatment, her height was increased to 129.6 cm (-1.0 SD height for age) at 9 and 4/12 years, indicating an effective response to GH treatment.

Agonists and Antagonists of TGF-β Family Ligands

The discovery of the transforming growth factor β (TGF-β) family ligands and the realization that their bioactivities need to be tightly controlled temporally and spatially led to intensive research that has identified a multitude of extracellular modulators of TGF-β family ligands, uncovered their functions in developmental and pathophysiological processes, defined the mechanisms of their activities, and explored potential modulator-based therapeutic applications in treating human diseases. These studies revealed a diverse repertoire of extracellular and membrane-associated molecules that are capable of modulating TGF-β family signals via control of ligand availability, processing, ligand-receptor interaction, and receptor activation. These molecules include not only soluble ligand-binding proteins that were conventionally considered as agonists and antagonists of TGF-β family of growth factors, but also extracellular matrix (ECM) proteins and proteoglycans that can serve as "sink" and control storage and release of both the TGF-β family ligands and their regulators. This extensive network of soluble and ECM modulators helps to ensure dynamic and cell-specific control of TGF-β family signals. This article reviews our knowledge of extracellular modulation of TGF-β growth factors by diverse proteins and their molecular mechanisms to regulate TGF-β family signaling.

β-Galactoside-mediated tissue organization during islet reconstitution

We have previously reported that multi-cellular heteroaggregates comprising murine pancreatic α (αTC1.6) and β (MIN6-m9) cell lines spontaneously acquired islet-like architecture and displayed higher insulin secretion rates. However, the mechanisms of self-organization remain unclear. The objective of this study is to examine the possibility that a sugar chain participates in the mutual recognition of the cells during reconstitution of the islet-like structure in vitro. Using a lectin-binding assay, we identified Erythrina cristagalli agglutinin (ECA), which particularly recognizes the β-galactoside structure on the surfaces of MIN6-m9 cells. The self-organization of αTC1.6 and MIN6-m9 was obstructed using ECA-bound MIN6-m9 cells. Lactose neutralized the ECA's inhibitory effect on the autonomous rearrangement of αTC1.6 and MIN6-m9 cells, indicating that the inhibition of cell arrangement by ECA was mediated via β-galactoside. We concluded that a β-galactoside sugar chain was central to the reconstitution of the pancreatic islet-like architecture in vitro.