Histone Acetylation Influences the Activity of Sox9-related Transcriptional Complex

Chondrocyte differentiation is the fundamental process in skeletal development. From the mesenchymal condensation of chondroprogenitors to the hypertrophic maturation of chondrocytes, chondrogenesis is sequentially regulated by cross-talk among transcription factors, growth factors, and chromatin structure. The master transcription factor Sry-type HMG box (Sox) 9 has an essential role in the expression of chondrogenic genes through the association with Sox9-binding sites on its target genes. Several transcription factors and coactivators, such as Scleraxis/E47 and p300, cooperatively modulate the Sox9-dependent transcription by interacting with Sox9. The Sox9-related transcriptional apparatus activates its target gene expression through p300-mediated histone acetylation on chromatin. The transforming growth factor (TGF)-β superfamily also plays a key role in chondrocyte differentiation. The TGF-β-regulated Smad3/4 complex activates Sox9-dependent transcription on chromatin by associating with Sox9 itself, and by recruiting p300 onto Sox9. These findings suggest that the epigenetic status including histone modification and chromatin structure, directly influences Sox9-regulated chondrocyte differentiation. In this article, we review the regulators of Sox9 expression itself, modulators of posttranslational Sox9 function, and Sox9-associating factors in the Sox9-dependent epigenetic regulation during chondrogenesis

UD_Japanese-CEJC: Dependency Relation Annotation on Corpus of Everyday Japanese Conversation

Conference name: the 24th Meeting of the Special Interest Group on Discourse and Dialogue, Conference place: Prague, Czechia, Session period: 2023/09/11-15, Organizer: Association for Computational Linguisticsapplication/pdfNational Institute for Japanese Language and LinguisticsTohoku UniversityMegagon Labs, Tokyo, Recruit Co., LtdNational Institute for Japanese Language and LinguisticsIn this study, we have developed Universal Dependencies (UD) resources for spoken Japanese in the Corpus of Everyday Japanese Conversation (CEJC). The CEJC is a large corpus of spoken language that encompasses various everyday conversations in Japanese, and includes word delimitation and part-of-speech annotation. We have newly annotated Long Word Unit delimitation and Bunsetsu (Japanese phrase)-based dependencies, including Bunsetsu boundaries, for CEJC. The UD of Japanese resources was constructed in accordance with hand-maintained conversion rules from the CEJC with two types of word delimitation, part-of-speech tags and Bunsetsu-based syntactic dependency relations. Furthermore, we examined various issues pertaining to the construction of UD in the CEJC by comparing it with the written Japanese corpus and evaluating UD parsing accuracy.conference pape

Stress responsive miR-23a attenuates skeletal muscle atrophy by targeting MAFbx /atrogin-1

Muscle atrophy occurs in many pathological states and results primarily from accelerated protein degradation by the ubiquitin-proteasome pathway. We used dexamethasone to induce muscle wasting and investigated the role of a microRNA (miRNA) in the control of muscle-specific E3 ubiquitin ligase MAFbx/atrogin-1. Here we show that miR-23a suppresses MAFbx/atrogin-1 translation by binding to 3'UTR of the mRNA. Furthermore, ectopic expression of miR-23a is sufficient to protect myocytes from atrophy in vitro and in vivo in response to dexamethasone treatment, and heat stress-induced miR-23a protects muscle from dexamethasone-induced muscle atrophy. Our surprising discovery of the physiological role of miR-23a in preventing the atrophy program should lay the basis not only for further understanding of the mechanisms of muscle wasting in diverse diseases, but also for developing novel therapies for these debilitating conditions

Mesenchymal progenitor cell markers in human articular cartilage: normal distribution and changes in osteoarthritis

INTRODUCTION: Recent findings suggest that articular cartilage contains mesenchymal progenitor cells. The aim of this study was to examine the distribution of stem cell markers (Notch-1, Stro-1 and VCAM-1) and of molecules that modulate progenitor differentiation (Notch-1 and Sox9) in normal adult human articular cartilage and in osteoarthritis (OA) cartilage. METHODS: Expression of the markers was analyzed by immunohistochemistry (IHC) and flow cytometry. Hoechst 33342 dye was used to identify and sort the cartilage side population (SP). Multilineage differentiation assays including chondrogenesis, osteogenesis and adipogenesis were performed on SP and non-SP (NSP) cells. RESULTS: A surprisingly high number (>45%) of cells were positive for Notch-1, Stro-1 and VCAM-1 throughout normal cartilage. Expression of these markers was higher in the superficial zone (SZ) of normal cartilage as compared to the middle zone (MZ) and deep zone (DZ). Non-fibrillated OA cartilage SZ showed reduced Notch-1 and Sox9 staining frequency, while Notch-1, Stro-1 and VCAM-1 positive cells were increased in the MZ. Most cells in OA clusters were positive for each molecule tested. The frequency of SP cells in cartilage was 0.14 +/- 0.05% and no difference was found between normal and OA. SP cells displayed chondrogenic and osteogenic but not adipogenic differentiation potential. CONCLUSIONS: These results show a surprisingly high number of cells that express putative progenitor cell markers in human cartilage. In contrast, the percentage of SP cells is much lower and within the range of expected stem cell frequency. Thus, markers such as Notch-1, Stro-1 or VCAM-1 may not be useful to identify progenitors in cartilage. Instead, their increased expression in OA cartilage implicates involvement in the abnormal cell activation and differentiation process characteristic of OA

Mohawk promotes the maintenance and regeneration of the outer annulus fibrosus of intervertebral discs.

The main pathogenesis of intervertebral disc (IVD) herniation involves disruption of the annulus fibrosus (AF) caused by ageing or excessive mechanical stress and the resulting prolapse of the nucleus pulposus. Owing to the avascular nature of the IVD and lack of understanding the mechanisms that maintain the IVD, current therapies do not lead to tissue regeneration. Here we show that homeobox protein Mohawk (Mkx) is a key transcription factor that regulates AF development, maintenance and regeneration. Mkx is mainly expressed in the outer AF (OAF) of humans and mice. In Mkx(-/-) mice, the OAF displays a deficiency of multiple tendon/ligament-related genes, a smaller OAF collagen fibril diameter and a more rapid progression of IVD degeneration compared with the wild type. Mesenchymal stem cells overexpressing Mkx promote functional AF regeneration in a mouse AF defect model, with abundant collagen fibril formation. Our results indicate a therapeutic strategy for AF regeneration

Spinal schwannomas: a review of 42 cases.

&#60;P&#62;In this study, 42 cases of spinal schwannomas are reviewed. We analyzed the therapeutic results of patients with spinal schwannomas in order to investigate the factors which affect the clinical outcomes. Early diagnosis and treatment could help procure a good result for the patient. The delay in diagnosis and the subsequent duration of symptoms was significantly longer in cases of lumbar lesions compared to cervical and thoracic lesions. Tumor recurrence was rare, but in some cases where complete resection was not possible, close follow-up of the patients postoperatively with MRI was indicated.&#60;/P&#62;</p

Identification of targets of tumor suppressor microRNA-34a using a reporter library system

miRNAs play critical roles in various biological processes by targeting specific mRNAs. Current approaches to identifying miRNA targets are insufficient for elucidation of a miRNA regulatory network. Here, we created a cell-based screening system using a luciferase reporter library composed of 4,891 full-length cDNAs, each of which was integrated into the 3′ UTR of a luciferase gene. Using this reporter library system, we conducted a screening for targets of miR-34a, a tumor-suppressor miRNA. We identified both previously characterized and previously uncharacterized targets. miR-34a overexpression in MDA-MB-231 breast cancer cells repressed the expression of these previously unrecognized targets. Among these targets, GFRA3 is crucial for MDA-MB-231 cell growth, and its expression correlated with the overall survival of patients with breast cancer. Furthermore, GFRA3 was found to be directly regulated by miR-34a via its coding region. These data show that this system is useful for elucidating miRNA functions and networks

Expression and localization of connective tissue growth factor (CTGF/Hcs24/CCN2) in osteoarthritic cartilage

AbstractObjectiveThe investigation of the expression and localization of connective tissue growth factor/hypertrophic chondrocyte-specific gene product 24/CCN family member 2 (CTGF/Hcs24/CCN2) in normal and osteoarthritic (OA) cartilage, and quantification of CTGF/Hcs24-positive cells.MethodsCartilage samples of patients (n=20) with late stage OA were obtained at total joint replacement surgery. Morphologically normal cartilage was harvested for comparison purposes from the femoral heads of 6 other patients with femoral neck fracture. Paraffin-embedded sections were stained by Safranin O. The severity of the OA lesions was divided into four stages (normal, early, moderate, and severe). The localization of protein and mRNA for CTGF/Hcs24 was investigated by immunohistochemistry and in situ hybridization, respectively. The population of CTGF/Hcs24-positive chondrocytes in OA cartilage and chondro-osteophyte was quantified by counting the number of the cells under light microscopy.ResultsSignals for CTGF/Hcs24 were detected in a small percentage of chondrocytes throughout the layers of normal cartilage. In early stage OA cartilage, the CTGF/Hcs24-positive chondrocytes were localized mainly in the superficial layer. In moderate to severe OA cartilage, intense staining for CTGF/Hcs24 was observed in proliferating chondrocytes forming cell clusters next to the cartilage surface. In chondro-osteophyte, strong signals were found in the chondrocytes of the proliferative and hypertrophic zones.ConclusionCTGF/Hcs24 expression was detected in both normal and OA chondrocytes of human samples. The results of the current study suggested that expression of CTGF/Hcs24 was concomitant with development of OA lesions and chondrocyte differentiation in chondro-osteophyte

Smad3 activates the Sox9-dependent transcription on chromatin

Transforming growth factor (TGF)-β has an essential role for the Sry-type high-mobility-group box (Sox)-regulated chondrogenesis. Chondrogenic differentiation is also controlled by chromatin-mediated transcription. We have previously reported that TGF-β-regulated Smad3 induces chondrogenesis through the activation of Sox9-dependent transcription. However, the cross-talk between TGF-β signal and Sox9 on chromatin-mediated transcription has not been elucidated. In the present study, we investigated the activity of Smad3, Sox9, and coactivator p300 using an in vitro chromatin assembly model. Luciferase reporter assays revealed that Smad3 stimulated the Sox9-mediated transcription in a TGF-β-dependent manner. Recombinant Sox9 associated with phosphorylated Smad3/4 and recognized the enhancer region of type II collagen gene. In vitro transcription and S1 nuclease assays showed that Smad3 and p300 cooperatively activated the Sox9-dependent transcription on chromatin template. The combination treatment of phosphorylated Smad3, Sox9, and p300 were necessary for the activation of chromatin-mediated transcription. These findings suggest that TGF-β signal Smad3 plays a key role for chromatin remodeling to induce chondrogenesis via its association with Sox9