Metabolic profiling of synovial fluid in human temporomandibular joint osteoarthritis.

Introduction: Temporomandibular joint (TMJ) osteoarthritis (OA) is a common TMJ degenerative disease with an unclear mechanism. Synovial fluid (SF), an important component of TMJ, contains various proteins and metabolites that may directly contribute to OA. The present study aimed to investigate the influence of SF in TMJOA at the metabolite level. Methods: Untargeted and widely targeted metabolic profiling were employed to identify metabolic changes in SF of 90 patients with different TMJOA grades according to TMJ magnetic resonance imaging. Results: A total 1498 metabolites were detected. Most of the metabolites were amino acids and associated metabolites, benzene and substituted derivatives, and lipids. Among patients with mild, moderate and severe TMJOA, 164 gradually increasing and 176 gradually decreasing metabolites were identified, indicating that biosynthesis of cofactors, choline metabolism, mineral absorption and selenocompound metabolism are closely related to TMJOA grade. Combined metabolomics and clinical examination revealed 37 upregulated metabolites and 16 downregulated metabolites in patients with pain, of which 19 and 26 metabolites were positively and negatively correlated, respectively, with maximum interincisal opening. A model was constructed to diagnose TMJOA grade and nine biomarkers were identified. The identified metabolites are key to exploring the mechanism of TMJOA. Discussion: In the present study, a metabolic profile was constructed and assessed using a much larger number of human SF samples from patients with TMJOA, and a model was established to contribute to the diagnosis of TMJOA grade. The findings expand our knowledge of metabolites in human SF of TMJOA patients, and provide an important basis for further research on the pathogenesis and treatment of TMJOA.

Factors Influencing Mandibular Deviation: A Retrospective Clinical Study.

This study aimed to investigate the correlation between mandibular deviation (MD) and possible clinical factors in patients with anterior disc displacement (ADD). This retrospective clinical study enrolled 296 patients with ADD, diagnosed using magnetic resonance imaging, from 2015 to 2018. The clinical symptoms and medical histories of these patients were carefully examined and recorded. Mandibular deviation was the primary outcome variable confirmed by a combination of clinical examination and facial photographs or posteroanterior cephalograms. The primary predictor variable was ADD staging. Secondary predictor variables included condylar height and distance of disc displacement. Other predictor variables were age, sex, disease course, oral parafunctions, depression, and bone mineral density. We used logistic regression to examine the correlation between the MD and all predictor variables. The χ2 test and analysis of variance were used to exclude the correlation between the predictor variables. In this study, the prevalence of MD was 77% among 278 patients with ADD. Bilateral ADD staging significantly contributed to MD on both sides. The odds ratio increased with the deterioration of disc displacement. The present study demonstrated that the ADD staging influences the condylar height and MD, and that articular disk position should be considered while treating MD.

Single-cell RNA sequencing reveals neurovascular-osteochondral network crosstalk during temporomandibular joint osteoarthritis: Pilot study in a human condylar cartilage.

Purpose: Temporomandibular joint osteoarthritis (TMJ-OA) is one of the most complex temporomandibular disorders, causing pain and dysfunction. The main pathological feature of TMJ-OA is neurovascular invasion from the subchondral bone to the condylar cartilage. This study aimed to discover the cells and genes that play an important role in the neurovascular-osteochondral network crosstalk in human TMJ-OA. Materials and methods: Condylar cartilages from patient with TMJ-OA were divided into OA group, and others from patients with benign condylar hyperplasia (CH) were used as control for further single-cell RNA-sequencing (scRNA-seq). Hematoxylin and eosin staining were performed. The cells and genes in the condylar cartilage were identified and analyzed by scRNA-seq. Results: Histological analysis revealed blood vessel invasion and ossification in the TMJ-OA condylar cartilage. The scRNA-seq identified immune cells, endothelial cells, and chondrocytes in the TMJ-OA condylar cartilage. Macrophages, especially M1-like macrophages, contributed to the inflammation, angiogenesis, and innervation. CD31+ endothelial cells contributed to the bone mineralization. The TMJ-OA cartilage chondrocytes highly expressed genes related to inflammation, angiogenesis, innervation, and ossification. The hub genes contributing to these processes in the TMJ-OA chondrocytes included CTGF, FBN1, FN1, EGFR, and ITGA5. Conclusion: Our study marks the first time scRNA-seq was used to identify the cells and genes in a human TMJ-OA condylar cartilage, and neurovascular-osteochondral network crosstalk during the human TMJ-OA process was demonstrated. Targeting the crosstalk of these processes may be a potential comprehensive and effective therapeutic strategy for human TMJ-OA.

miR-335-5p inhibits endochondral ossification by directly targeting SP1 in TMJ OA.

OBJECTIVE: During the development of temporomandibular joint osteoarthritis, endochondral ossification is compromised which leads to condylar degeneration; miR-335-5p in endochondral ossification in osteoarthritic condylar cartilage tissue remains unclear. METHODS: Up-regulated microRNA and its target gene were searched for endochondral ossification in osteoarthritis articular cartilage. The effect of increased or decreased miR-335-5p on endochondral ossification was evaluated by transfecting miR-335-5p mimics or miR-335-5p inhibitor in vitro in chondrocytes C28/I2. Finally, we injected the temporomandibular joint of rats intra-articularly with agomiR-335 in a unilateral anterior crossbite rat model to determine the in vivo regulation of miR-335. RESULTS: After the onset of temporomandibular joint osteoarthritis, miR-335-5p levels were gradually up-regulated, whereas endochondral ossification-related genes were down-regulated in condylar cartilage specimens. Our results showed that miR-335 inhibited endochondral ossification after administration of a miR-335 antagonist into the temporomandibular joint articular cavity of a unilateral anterior crossbite rat model. AgomiR-335, a miR-335 agonist, inhibited matrix mineralization in fibrocartilage stem cells in vitro and then miR-335-5p negatively regulated chondrocyte activity by directly targeting SP1 via promoting transforming growth factor-ß/Smad signalling. CONCLUSION: miR-335-5p can significantly inhibit endochondral ossification; therefore, its inhibition may be beneficial for the treatment of temporomandibular joint osteoarthritis.

Chitosan based macromolecular hydrogel loaded total glycosides of paeony enhances diabetic wound healing by regulating oxidative stress microenvironment.

Oxidative stress microenvironment caused by reactive oxygen species (ROS) accumulation seriously hinders wound healing in diabetes, which brings great burden to global health. Various wound dressings on the market focus on delivering active substances to promote wound healing in diabetes. However, the complex pathological microenvironment of diabetic wounds often leads to the inactivation of delivery factors, which often leads to treatment failure, and thus, emerging therapeutic approaches are urgently needed. In this study, a macromolecular hydrogel synthesized by crosslinking N-carboxyethyl chitosan, hyaluronic acid-aldehyde, and adipic acid dihydrazide, with self-healing and injectable abilities was used to deliver total glycosides of paeony (TGP). The TGP incorporated hydrogel could obviously induce fibroblasts proliferation and secretion of various extracellular matrix proteins and growth factors, induce migration and angiogenesis of vein endothelial cells, and enhance macrophages polarization to M2 phenotype by eliminating accumulated ROS. In diabetic wound models, the ROS-scavenging hydrogel efficiently enhanced proliferation, re-epithelialization, collagen deposition, as well as angiogenesis in the wound area. Besides, the dressing induced the macrophages polarization from M1 phenotype (pro-inflammatory) to M2 phenotype (anti-inflammatory) and decreased the levels of inflammatory cytokines, thereby enhancing the diabetic wound healing. The wounds treated with TGP incorporated hydrogel almost completely healed 16 days after treatment. However, the residual wound areas in the groups of Con, INTRA, and Gel are 55.2 ± 4.6 %, 33.7 ± 6.5 %, and 34.9 ± 6.1 % on the 16th day, respectively. This hydrogel with pathological microenvironment improvement ability affords a novel therapeutic strategy for enhancing healing of chronic diabetic wound.

Activating Wnt/ß-catenin signaling by autophagic degradation of APC contributes to the osteoblast differentiation effect of soy isoflavone on osteoporotic mesenchymal stem cells.

The functional role of autophagy in regulating differentiation of bone marrow mesenchymal stem cells (MSCs) has been studied extensively, but the underlying mechanism remains largely unknown. The Wnt/ß-catenin signaling pathway plays a pivotal role in the initiation of osteoblast differentiation of mesenchymal progenitor cells, and the stability of core protein ß-catenin is tightly controlled by the APC/Axin/GSK-3ß/Ck1α complex. Here we showed that genistein, a predominant soy isoflavone, stimulated osteoblast differentiation of MSCs in vivo and in vitro. Female rats were subjected to bilateral ovariectomy (OVX); four weeks after surgery the rats were orally administered genistein (50 mg·kg-1·d-1) for 8 weeks. The results showed that genistein administration significantly suppressed the bone loss and bone-fat imbalance, and stimulated bone formation in OVX rats. In vitro, genistein (10 nM) markedly activated autophagy and Wnt/ß-catenin signaling pathway, and stimulated osteoblast differentiation in OVX-MSCs. Furthermore, we found that genistein promoted autophagic degradation of adenomatous polyposis coli (APC), thus initiated ß-catenin-driven osteoblast differentiation. Notably, genistein activated autophagy through transcription factor EB (TFEB) rather than mammalian target of rapamycin (mTOR). These findings unveil the mechanism of how autophagy regulates osteogenesis in OVX-MSCs, which expands our understanding that such interplay could be employed as a useful therapeutic strategy for treating postmenopausal osteoporosis.

Rapid induction and long-term self-renewal of neural crest-derived ectodermal chondrogenic cells from hPSCs.

Articular cartilage is highly specific and has limited capacity for regeneration if damaged. Human pluripotent stem cells (hPSCs) have the potential to generate any cell type in the body. Here, we report the dual-phase induction of ectodermal chondrogenic cells (ECCs) from hPSCs through the neural crest (NC). ECCs were able to self-renew long-term (over numerous passages) in a cocktail of growth factors and small molecules. The cells stably expressed cranial neural crest-derived mandibular condylar cartilage markers, such as MSX1, FOXC1 and FOXC2. Compared with chondroprogenitors from iPSCs via the paraxial mesoderm, ECCs had single-cell transcriptome profiles similar to condylar chondrocytes. After the removal of the cocktail sustaining self-renewal, the cells stopped proliferating and differentiated into a homogenous chondrocyte population. Remarkably, after transplantation, this cell lineage was able to form cartilage-like structures resembling mandibular condylar cartilage in vivo. This finding provides a framework to generate self-renewing cranial chondrogenic progenitors, which could be useful for developing cell-based therapy for cranial cartilage injury.

T-cell expression of Bruton's tyrosine kinase promotes autoreactive T-cell activation and exacerbates aplastic anemia.

The role of Bruton's tyrosine kinase (BTK) in BCR signaling is well defined, and BTK is involved in B-cell development, differentiation, and malignancies. However, the expression of Btk in T cells and its role in T-cell function remain largely unknown. Here, we unexpectedly found high expression and activation of BTK in T cells. Deficiencies in BTK resulted in the impaired activation and proliferation of autoreactive T cells and ameliorated bone marrow failure (BMF) in aplastic anemia. Mechanistically, BTK is activated after TCR engagement and then phosphorylates PLCγ1, thus promoting T-cell activation. Treatment with acalabrutinib, a selective BTK inhibitor, decreased T-cell proliferation and ameliorated BMF in mice with aplastic anemia. Our results demonstrate an unexpected role of BTK in optimal T-cell activation and in the pathogenesis of autoimmune aplastic anemia, providing insights into the molecular regulation of T-cell activation and the pathogenesis of T-cell-mediated autoimmune disease.

MHC Class I Molecules Exacerbate Viral Infection by Disrupting Type I Interferon Signaling.

MHC class I molecules are key in the presentation of antigen and initiation of adaptive CD8+ T cell responses. In addition to its classical activity, MHC I may possess nonclassical functions. We have previously identified a regulatory role of MHC I in TLR signaling and antibacterial immunity. However, its role in innate antiviral immunity remains unknown. In this study, we found a reduced viral load in MHC I-deficient macrophages that was independent of type I IFN production. Mechanically, MHC I mediated viral suppression by inhibiting the type I IFN signaling pathway, which depends on SHP2. Cross-linking MHC I at the membrane increased SHP2 activation and further suppressed STAT1 phosphorylation. Therefore, our data revealed an inhibitory role of MHC I in type I IFN response to viral infection and expanded our understanding of MHC I and antigen presentation.