Hepatitis B virus RNAs co-opt ELAVL1 for stabilization and CRM1-dependent nuclear export.

Hepatitis B virus (HBV) chronically infects 296 million people worldwide, posing a major global health threat. Export of HBV RNAs from the nucleus to the cytoplasm is indispensable for viral protein translation and genome replication, however the mechanisms regulating this critical process remain largely elusive. Here, we identify a key host factor embryonic lethal, abnormal vision, Drosophila-like 1 (ELAVL1) that binds HBV RNAs and controls their nuclear export. Using an unbiased quantitative proteomics screen, we demonstrate direct binding of ELAVL1 to the HBV pregenomic RNA (pgRNA). ELAVL1 knockdown inhibits HBV RNAs posttranscriptional regulation and suppresses viral replication. Further mechanistic studies reveal ELAVL1 recruits the nuclear export receptor CRM1 through ANP32A and ANP32B to transport HBV RNAs to the cytoplasm via specific AU-rich elements, which can be targeted by a compound CMLD-2. Moreover, ELAVL1 protects HBV RNAs from DIS3+RRP6+ RNA exosome mediated nuclear RNA degradation. Notably, we find HBV core protein is dispensable for HBV RNA-CRM1 interaction and nuclear export. Our results unveil ELAVL1 as a crucial host factor that regulates HBV RNAs stability and trafficking. By orchestrating viral RNA nuclear export, ELAVL1 is indispensable for the HBV life cycle. Our study highlights a virus-host interaction that may be exploited as a new therapeutic target against chronic hepatitis B.

Hepatitis B virus hijacks TSG101 to facilitate egress via multiple vesicle bodies.

Hepatitis B virus (HBV) chronically infects 296 million individuals and there is no cure. As an important step of viral life cycle, the mechanisms of HBV egress remain poorly elucidated. With proteomic approach to identify capsid protein (HBc) associated host factors and siRNA screen, we uncovered tumor susceptibility gene 101 (TSG101). Knockdown of TSG101 in HBV-producing cells, HBV-infected cells and HBV transgenic mice suppressed HBV release. Co-immunoprecipitation and site mutagenesis revealed that VFND motif in TSG101 and Lys-96 ubiquitination in HBc were essential for TSG101-HBc interaction. In vitro ubiquitination experiment demonstrated that UbcH6 and NEDD4 were potential E2 ubiquitin-conjugating enzyme and E3 ligase that catalyzed HBc ubiquitination, respectively. PPAY motif in HBc and Cys-867 in NEDD4 were required for HBc ubiquitination, TSG101-HBc interaction and HBV egress. Transmission electron microscopy confirmed that TSG101 or NEDD4 knockdown reduces HBV particles count in multivesicular bodies (MVBs). Our work indicates that TSG101 recognition for NEDD4 ubiquitylated HBc is critical for MVBs mediated HBV egress.

G-quadruplex in hepatitis B virus pregenomic RNA promotes its translation.

Hepatitis B virus (HBV) is a hepatotropic DNA virus that has a very compact genome. Due to this genomic density, several distinct mechanisms are used to facilitate the viral life cycle. Recently, accumulating evidence show that G-quadruplex (G4) in different viruses play essential regulatory roles in key steps of the viral life cycle. Although G4 structures in the HBV genome have been reported, their function in HBV replication remains elusive. In this study, we treated an HBV replication-competent cell line and HBV-infected cells with the G4 structure stabilizer pyridostatin (PDS) and evaluated different HBV replication markers to better understand the role played by the G4. In both models, we found PDS had no effect on viral precore RNA (pcRNA) or pre-genomic RNA (pgRNA), but treatment did increase HBeAg/HBc ELISA reads and intracellular levels of viral core/capsid protein (HBc) in a dose-dependent manner, suggesting post-transcriptional regulation. To further dissect the mechanism of G4 involvement, we used in vitro-synthesized HBV pcRNA and pgRNA. Interestingly, we found PDS treatment only enhanced HBc expression from pgRNA but not HBeAg expression from pcRNA. Our bioinformatic analysis and CD spectroscopy revealed that pgRNA harbors a conserved G4 structure. Finally, we introduced point mutations in pgRNA to disrupt its G4 structure and observed the resulting mutant failed to respond to PDS treatment and decreased HBc level in in vitro translation assay. Taken together, our data demonstrate that HBV pgRNA contains a G4 structure that plays a vital role in the regulation of viral mRNA translation.

SARS-CoV-2 NSP12 Protein Is Not an Interferon-ß Antagonist.

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is bringing an unprecedented health crisis to the world. To date, our understanding of the interaction between SARS-CoV-2 and host innate immunity is still limited. Previous studies reported that SARS-CoV-2 nonstructural protein 12 (NSP12) was able to suppress interferon-ß (IFN-ß) activation in IFN-ß promoter luciferase reporter assays, which provided insights into the pathogenesis of COVID-19. In this study, we demonstrated that IFN-ß promoter-mediated luciferase activity was reduced during coexpression of NSP12. However, we could show NSP12 did not affect IRF3 or NF-κB activation. Moreover, IFN-ß production induced by Sendai virus (SeV) infection or other stimulus was not affected by NSP12 at mRNA or protein level. Additionally, the type I IFN signaling pathway was not affected by NSP12, as demonstrated by the expression of interferon-stimulated genes (ISGs). Further experiments revealed that different experiment systems, including protein tags and plasmid backbones, could affect the readouts of IFN-ß promoter luciferase assays. In conclusion, unlike as previously reported, our study showed SARS-CoV-2 NSP12 protein is not an IFN-ß antagonist. It also rings the alarm on the general usage of luciferase reporter assays in studying SARS-CoV-2. IMPORTANCE Previous studies investigated the interaction between SARS-CoV-2 viral proteins and interferon signaling and proposed that several SARS-CoV-2 viral proteins, including NSP12, could suppress IFN-ß activation. However, most of these results were generated from IFN-ß promoter luciferase reporter assay and have not been validated functionally. In our study, we found that, although NSP12 could suppress IFN-ß promoter luciferase activity, it showed no inhibitory effect on IFN-ß production or its downstream signaling. Further study revealed that contradictory results could be generated from different experiment systems. On one hand, we demonstrated that SARS-CoV-2 NSP12 could not suppress IFN-ß signaling. On the other hand, our study suggests that caution needs to be taken with the interpretation of SARS-CoV-2-related luciferase assays.

Comparison and applicability of three induction methods of temporomandibular joint osteoarthritis in murine models.

BACKGROUND: Temporomandibular joint osteoarthritis (TMJ-OA) causes severe symptoms such as chewing difficulties, acute pain and even maxillofacial deformity. However, there is hardly any effective disease-curing strategy because of uncertainty in aetiology. Animal model is an excellent tool to investigate the mechanism, prevention and treatment on diseases. Currently, although several TMJ-OA animal models have been established, there are almost no comparative studies on different models, which poses a great challenge for selecting suitable models. OBJECTIVE: To compare three TMJ-OA induction methods and assess their applicability considering pathological changes in the cartilage, subchondral bone, osteoclasts, and synovium. METHODS: Murine models were employed and followed for 3 and 6 weeks after experimental procedures (surgery, injection, crossbite). The TMJ changes were evaluated by Safranin-O/Fast green staining, immunofluorescence staining, micro-CT, TRAP staining, and HE staining. RESULTS: In the Surgery group, a pronounced drop in bone volume fraction was observed. In the Injection group, chondrocytes were mostly disordered or arranged in clusters and a substantial increase in the OARSI score and osteoclasts was found. The OARSI score and osteoclasts also increased significantly in the Crossbite group, although to a lower extent compared with injection. CONCLUSION: Osteoarthritis-like changes were observed in all models. Concerning the applicability of the different induction methods, surgery might be an important resource for the assessment of post-traumatic TMJ-OA and subchondral bone changes in early stages. Injection induces a severe end-stage osteoarthritis in a short time and provides model basis for advanced TMJ-OA. Crossbite might be more reasonable model to explore the pathogenesis mechanism of temporomandibular arthritis due to occlusal disorders.

d-mannose attenuates lipopolysaccharide-induced osteolysis via CPT1A-Mediated lipid metabolic regulation in macrophages.

Inflammatory osteolysis is usually linked to the activation of proinflammatory macrophage and the consequent excessive osteoclast formation. Emerging evidence indicates that agents or drugs targeting lipid metabolism in macrophages might be potential in the prevention and treatment of osteolysis. d-mannose, as a natural-existed metabolic regulator, exerts strong effects on attenuating osteopenia and inflammation. However, whether d-mannose is therapeutically effective on osteolysis and whether a metabolic mechanism counts for the effect remain to be addressed. Here, by using an in vivo lipopolysaccharide (LPS)-induced inflammatory osteolysis mouse model as well as an in vitro LPS-induced inflammatory macrophage culture system, we show that d-mannose attenuates inflammatory osteolysis and inhibits excessive osteoclastogenesis by reversing the LPS-induced activation of proinflammatory macrophage. Mechanically, d-mannose recovers LPS-suppressed Cpt1a transcription and promotes lipid metabolism of macrophage. Treatment with etomoxir, an inhibitor of CPT1A, abolishes the effects of d-mannose on LPS-treated macrophage in vitro and eliminates its protection against osteolysis in vivo. Collectively, our results imply that d-mannose attenuates LPS-induced osteolysis by manipulating CPT1A-mediated lipid metabolism in macrophages. Our results disclose the unrecognized utilization of d-mannose as an effective intervention against inflammatory osteolysis and provide evidence to manage inflammatory scenarios by therapeutically targeting lipid metabolism in macrophage.

The Late Domain of Prototype Foamy Virus Gag Facilitates Autophagic Clearance of Stress Granules by Promoting Amphisome Formation.

Prototype foamy virus (PFV), a complex retrovirus belonging to Spumaretrovirinae, maintains lifelong latent infection. The maintenance of lifelong latent infection by viruses relies on the repression of the type I interferon (IFN) response. However, the mechanism involving PFV latency, especially regarding the suppression of the IFN response, is poorly understood. Our previous study showed that PFV promotes autophagic flux. However, the underlying mechanism and the role of PFV-induced autophagy in latent infection have not been clarified. Here, we report that the PFV viral structural protein Gag induced amphisome formation and triggered autophagic clearance of stress granules (SGs) to attenuate type I IFN production. Moreover, the late domain (L-domain) of Gag played a central role in Alix recruitment, which promoted endosomal sorting complex required for transport I (ESCRT-I) formation and amphisome accumulation by facilitating late endosome formation. Our data suggest that PFV Gag represses the host IFN response through autophagic clearance of SGs by activating the endosome-autophagy pathway. More importantly, we found a novel mechanism by which a retrovirus inhibits the SG response to repress the type I IFN response.IMPORTANCE Maintenance of lifelong latent infection for viruses relies on repression of the type I IFN response. Autophagy plays a double-edged sword in antiviral immunity. However, the role of autophagy in the regulation of the type I IFN response and the mechanism involving virus-promoted autophagy have not been fully elucidated. SGs are an immune complex associated with the antiviral immune response and are critical for type I IFN production. Autophagic clearance of SGs is one means of degradation of SGs and is associated with regulation of immunity, but the detailed mechanism remains unclear. In this article, we demonstrate that PFV Gag recruits ESCRT-I to facilitate amphisome formation. Our data also suggest that amphisome formation is a critical event for autophagic clearance of SGs and repression of the type I IFN response. More importantly, we found a novel mechanism by which a retrovirus inhibits the SG response to repress the type I IFN response.

The Long-Noncoding RNA lnc-NONH Enhances the Early Transcription of Prototype Foamy Virus Via Upregulating Expression of miR-34c-5p and Tas Protein.

BACKGROUND: Prototype foamy virus (PFV) is a complex and unique retrovirus with the longest genome among the retroviruses and is used as a vector for gene therapies. The viral Tas protein transactivates the viral long terminal repeat promoter and is required for viral replication. We have utilized RNA sequencing to identify and characterize the long-noncoding RNA NONHSAG000101 (lnc-NONH), which markedly increases in PFV-infected cells. However, little is known about the function of lnc-NONH. OBJECTIVES: We aim to explore the role of lnc-NONH during PFV infection. METHODS: To assess the lnc-NONH role during PFV infection, the siRNAs were used to silence the lnc-NONH expression. The microRNA (miRNA) mimic and inhibitor were employed to explore the function of lnc-NONH-related miRNA miR-34c-5p. Quantitative real-time polymerase chain reaction assay and Western blotting were applied to measure the mRNA and protein levels of PFV transactivator Tas. Luciferase assay was used to determine the transcriptional activity of the PFV unique internal promoter (IP). RESULTS: lnc-NONH promotes the expression of PFV Tas and miR-34c-5p. The interaction between lnc-NONH and miR-34c-5p enhances the transcriptional activity of the PFV IP. CONCLUSIONS: In the current study, we report a novel mechanism for the lnc-NONH-mediated upregulation of Tas expression. Our findings contribute to the understanding of regulatory network of Tas expression and PFV replication.

Effect of systemic delivery of Substance P on experimental tooth movement in rats.

INTRODUCTION: The purpose of this study was to investigate the effect of systemic delivery of Substance P (SP) on experimental tooth movement. METHODS: Forty-eight adult Sprague-Dawley rats were randomly divided into 2 groups and their maxillary first molars were mesially moved with the use of closed-coil springs. The experiment group received systemic injection of SP and the control group received phosphate-buffered saline solution. Transportation distances of first molars were measured. Hematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, and immunohistochemistry staining were performed to evaluate alveolar bone remodeling. Then the interferon (IFN) γ and tumor necrosis factor (TNF) α concentrations in peripheral blood and local periodontal tissue were measured. Finally, the effects of SP on bone marrow-derived stem cell (BMSC) proliferation and migration were tested in vitro. RESULTS: Systemic delivery of SP significantly increased the distance of tooth movement and stimulated both osteoclast and osteoblast activities. The concentrations of IFN-γ and TNF-α increased in peripheral blood at early phases of the experiment and decreased in periodontal tissue at late phases. In vitro, the proliferation and migration of BMSCs were promoted by SP. CONCLUSIONS: Systemic delivery of SP can accelerate orthodontic tooth movement and promote alveolar bone remodeling potentially through immunomodulation and mobilizing endogenous mesenchymal stem cells.

Stratifin-mediated activation of AKT signaling and therapeutic targetability in hepatocellular carcinoma progression.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and presents a significant threat to human health. Despite its prevalence, the underlying regulatory mechanisms of HCC remain unclear. In this study, we integrated RNA-seq datasets, proteome dataset and survival analysis and unveiled Stratifin (SFN) as a potential prognostic biomarker for HCC. SFN knockdown inhibited HCC progression in cell cultures and mouse models. Conversely, ectopic expression of Sfn in primary mouse HCC model accelerated HCC progression. Mechanistically, SFN acted as an adaptor protein, activating AKT1 signaling by fostering the interaction between PDK1 and AKT1, with the R56 and R129 sites on SFN proving to be crucial for this binding. In the syngeneic implantation model, the R56A/R129A mutant of SFN inhibited Akt signaling activation and impeded HCC growth. Additionally, peptide inhibitors designed based on the binding motif of AKT1 to SFN significantly inhibited HCC progression. In summary, our findings establish that SFN promotes HCC progression by activating AKT signaling through the R56 and R129 binding sites. This discovery opens new avenues for a promising therapeutic strategy for the treatment of HCC.

Coxsackievirus A16 infection triggers apoptosis in RD cells by inducing ER stress.

Coxsackievirus A16 (CA16) infection, which is responsible for hand, foot and mouth disease (HFMD), has become a common health problem in Asia due to the prevalence of the virus. Thus, it is important to understand the pathogenesis of CA16 infection. Viruses that induce endoplasmic reticulum (ER) stress are confronted with the unfolded protein response (UPR), which may lead to apoptotic cell death and influence viral replication. In this study, we found that CA16 infection could induce apoptosis and ER stress in RD cells. Interestingly, apoptosis via the activation of caspase-3, -8 and -9 in the extrinsic or intrinsic apoptotic pathways in RD cells was inhibited by 4-phenyl butyric acid (4PBA), a chemical chaperone that reduces ER stress. These results suggest that CA16 infection leads to ER stress, which in turn results in prolonged ER stress-induced apoptosis. This study provides a new basis for understanding CA16 infection and host responses.

Mechanotransduction in cancer stem cells.

The cancer stem cell (CSC) concept, which arose about a decade ago, proposes that tumor growth is sustained by a subpopulation of highly malignant cells. These cells, termed CSCs, are capable of extensive self-renewal that contributes to metastasis and treatment resistance. Therefore, therapeutic strategies that target CSCs should be developed for improving outcomes of cancer patients. Recent progress has highlighted the importance of physical properties of the extracellular matrix and mechanotransduction pathway in cancer cells during cancer development. On the other hand, the significance of CXCR1, an upstream signal of FAK/PI3K/Akt has been revealed in CSCs. FAK/PI3K/Akt is a key signal mediator in mechanotransduction pathway. Therefore, mechanotransduction could be a new target for CSCs, and would be an innovative way to treat cancer by inhibiting FAK/PI3K/Akt.

Antibiotic-induced gut bacteria depletion has no effect on HBV replication in HBV immune tolerance mouse model.

Commensal microbiota is closely related to Hepatitis B virus (HBV) infection. Gut bacteria maturation accelerates HBV immune clearance in hydrodynamic injection (HDI) HBV mouse model. However, the effect of gut bacteria on HBV replication in recombinant adeno-associated virus (AAV)-HBV mouse model with immune tolerance remains obscure. We aim to investigate its role on HBV replication in AAV-HBV mouse model. C57BL/6 mice were administrated with broad-spectrum antibiotic mixtures (ABX) to deplete gut bacteria and intravenously injected with AAV-HBV to establish persistent HBV replication. Gut microbiota community was analyzed by fecal qPCR assay and 16S ribosomal RNA (rRNA) gene sequencing. HBV replication markers in blood and liver were determined by ELISA, qPCR assay and Western blot at indicated time points. Immune response in AAV-HBV mouse model was activated through HDI of HBV plasmid or poly(I:C) and then detected by quantifying the percentage of IFN-γ+/CD8+ T cells in the spleen via flow cytometry as well as the splenic IFN-γ mRNA level via qPCR assay. We found that antibiotic exposure remarkably decreased gut bacteria abundance and diversity. Antibiotic treatment failed to alter the levels of serological HBV antigens, intrahepatic HBV RNA transcripts and HBc protein in AAV-HBV mouse model, but contributed to HBsAg increase after breaking of immune tolerance. Overall, our data uncovered that antibiotic-induced gut bacteria depletion has no effect on HBV replication in immune tolerant AAV-HBV mouse model, providing new thoughts for elucidating the correlation between gut bacteria dysbiosis by antibiotic abuse and clinical chronic HBV infection.

High dose lipopolysaccharide triggers polarization of mouse thymic Th17 cells in vitro in the presence of mature dendritic cells.

Lipopolysaccharide (LPS) plays an important role in the activation of innate immune cells, leading to secretion of proinflammatory factors and bridging the adaptive immune system. Exposing total mouse thymic cells culture to LPS induced a unique expression profile of cytokines (IL-17A, IL-17F, and IL-22) and the essential ROR-γt master transcription factor, which suggested a preferential differentiation of thymocytes towards the Th17 cell phenotype. Th17-polarizing molecules (IL-23, IL-23R, IL-6, and TGF-ß) and IL-17A(+)CD4(+) thymocytes were also specifically produced by the in vitro LPS-stimulation of thymic cells. Furthermore, both the expression of Th17 differentiation-related molecules and the frequency of Th17 cells were significantly up-regulated with increasing doses of LPS, as evidenced by quantitative RT-PCR and flow cytometric analysis, respectively. The expressions and frequency reached maximum levels when LPS exposure had been maintained at an extremely high concentration (100 µg/mL) for 48 h. On the other hand, depletion of thymic dendritic cells (DCs) blocked the LPS-induced polarization of thymus-derived Th17 cell lineage. Addition of bone marrow-derived DCs (BMDCs) to the purified immature CD4(+) CD62L(low) thymocytes culture recovered the switch towards Th17 cells, which synergistically prompted the cytotoxic activity of CD8(+) T cells. Taken together, our data indicates that high doses of LPS can promote the differentiation of mouse thymus-derived Th17 cells by a mechanism involving components associated with mature DCs.

PEG10 promotes the migration of human Burkitt's lymphoma cells by up-regulating the expression of matrix metalloproteinase-2 and -9.

PURPOSE: Paternally expressed gene 10 (PEG10) is important for apoptosis resistance in cancer cells; however, the effect of PEG10 on tumor cell migration remains poorly understood. In this study, we investigated the effects of PEG10 on proliferation, apoptosis, adhesion and migration in the Burkitt's lymphoma cell line, Raji. METHODS: Apoptosis was induced by 5-fluorouracil (5-FU) in pcDNA3.0/PEG10 transiently transfected HEK293T cells and PEG10-suppressed Raji cells. siRNAPEG10 was used to inhibit PEG10 expression. Fluorescence-activated cell sorting (FACS) were performed to analyze the effect of PEG10 on apoptosis. CCK-8 were performed to detect cell proliferation and adhesion. Matrigel invasion were performed using PEG10-suppressed Raji cells to investigate cell migration. The expression levels of matrix metalloproteinases -2and -9 (MMP-2 and MMP-9) were analyzed in PEG10-suppressed Raji cells using both real-time RT-PCR and Western blot analysis. RESULTS: HEK293T cells that overexpressed PEG10 exhibited greater viability 48 h following treatment with 5-FU, relative to control cells. Specific inhibition of PEG10 expression by siRNA resulted in inhibition of growth and apoptosis in Raji cells. Adherence and invasion capabilities were downregulated and expression levels of MMP-2 and MMP-9 were reduced in PEG10-suppressed Raji cells. CONCLUSIONS: Our findings demonstrated that PEG10 enhances the apoptotic resistance and viability of Raji cells. The migration and adherence invasion capacity of Raji cells could potentially be affected by regulation of the expression of MMP-2 and MMP-9. Our research provides a promising strategy for cancer immunotherapy of lymphoma.

Customized maxillary incisor position relative to dentoskeletal and soft tissue patterns in Chinese women: A retrospective study.

Objective: To provide reliable prediction models based on dentoskeletal and soft tissue variables for customizing maxillary incisor positions and to optimize digitalized orthodontic treatment planning. Methods: This study included 244 Chinese women (age, 18-40 years old) with esthetic profiles after orthodontic treatment with fixed appliances (133 in group I: 1° ≤ The angle between the nasion [N]-A point [A] plane and the N-B point [B] plane [ANB] ≤ 4°; 111 in group II: 4° < ANB ≤ 7°). Dental, skeletal, and soft tissue measurements were performed on lateral cephalograms of the participants. Correlation and multiple linear regression analyses were used to determine the influence of dentoskeletal and soft tissue variables on maxillary incisor position. Results: The ideal anteroposterior position of the maxillary incisor varied between sagittal skeletal patterns. The position of the maxillary incisor correlated with the sagittal discrepancy between the maxilla and the mandible (ANB), protrusion of the midface, nasal tip projection, development of the chin, and inclination of both the maxillary and mandibular incisors. Distance from the maxillary central incisor to nasion-pogonion plane predicted using multiple linear regression analysis was accurate and could be a practical measurement in orthodontic treatment planning. Conclusions: Instead of using an average value or norm, orthodontists should customize a patient's ideal maxillary incisor position using dentoskeletal and soft tissue evaluations.

SM22α-lineage niche cells regulate intramembranous bone regeneration via PDGFRß-triggered hydrogen sulfide production.

Bone stromal cells are critical for bone homeostasis and regeneration. Growing evidence suggests that non-stem bone niche cells support bone homeostasis and regeneration via paracrine mechanisms, which remain to be elucidated. Here, we show that physiologically quiescent SM22α-lineage stromal cells expand after bone injury to regulate diverse processes of intramembranous bone regeneration. The majority of SM22α-lineage cells neither act as stem cells in vivo nor show their expression patterns. Dysfunction of SM22α-lineage niche cells induced by loss of platelet-derived growth factor receptor ß (PDGFRß) impairs bone repair. We further show that PDGFRß-triggered hydrogen sulfide (H2S) generation in SM22α-lineage niche cells facilitates osteogenesis and angiogenesis and suppresses overactive osteoclastogenesis. Collectively, these data demonstrate that non-stem SM22α-lineage niche cells support the niche for bone regeneration with a PDGFRß/H2S-dependent regulatory mechanism. Our findings provide further insight into non-stem bone stromal niche cell populations and niche-regulation strategy for bone repair.

Hyoid Bone Position in Patients with and without Temporomandibular Joint Osteoarthrosis: A Cone-Beam Computed Tomography and Cephalometric Analysis.

OBJECTIVE: To assess the differences in hyoid bone position in patients with and without temporomandibular joint osteoarthrosis (TMJOA). METHODS: The present cross-sectional study was conducted in 427 participants whose osseous status was evaluated using cone-beam computed tomography and classified into normal, indeterminate osteoarthrosis (OA), and OA. The hyoid bone position and craniofacial characteristics were evaluated using cephalograms. Patients were divided into the normal group (N = 89), indeterminate OA group (N = 182), and OA group (N = 156). Descriptive statistics, one-way analysis of variance, and age- and sex-based stratified analyses were performed. P < 0.05 was considered statistically significant. RESULTS: The differences in Hy to MP, Hy-RGn, Hy to C3-RGn, C3-RGn, and Go-Hy-Me among the three groups were statistically significant. The differences in the Frankfort-mandibular plane angle, saddle angle, articular angle, gonial angle, ramus height, and posterior facial height were statistically significant. After adjusting age and sex, the Hy-RGn and C3-RGn in the normal group were significantly greater than the OA group. No statistical differences were observed in the hyoid measurements in the stratified analyses in males or subjects less than 18 years old. The differences in Hy to MP, Hy to C3-RGn, and Go-Hy-Me in female patients among the three groups were statistically significant. The differences in Hy to SN, Hy to FH, Hy to PP, Hy to MP, Hy-RGn, Hy-C3, Hy to C3-RGn, Go-Hy-Me, Hy-S, and C3-Hy-S in adults were statistically significant. CONCLUSION: The differences in the hyoid bone position, mainly relative to the mandible, were statistically significant in patients with or without TMJOA. The difference pattern varied among different age and sex groups. Clinical evaluation of the hyoid position must consider the age and sex of patients. Longitudinal studies are required to clarify the causal relationship between TMJOA and hyoid bone position.

D-mannose alleviates osteoarthritis progression by inhibiting chondrocyte ferroptosis in a HIF-2α-dependent manner.

OBJECTIVES: Chondrocyte ferroptosis contributes to osteoarthritis (OA) progression, and D-mannose shows therapeutic value in many inflammatory conditions. Here, we investigated whether D-mannose interferes in chondrocyte ferroptotic cell death during osteoarthritic cartilage degeneration. MATERIALS AND METHODS: In vivo anterior cruciate ligament transection (ACLT)-induced OA mouse model and an in vitro study of chondrocytes in an OA microenvironment induced by interleukin-1ß (IL-1ß) exposure were employed. Combined with Epas1 gene gain- and loss-of-function, histology, immunofluorescence, quantitative RT-PCR, Western blot, cell viability and flow cytometry experiments were performed to evaluate the chondroprotective effects of D-mannose in OA progression and the role of hypoxia-inducible factor 2 alpha (HIF-2 α) in D-mannose-induced ferroptosis resistance of chondrocytes. RESULTS: D-mannose exerted a chondroprotective effect by attenuating the sensitivity of chondrocytes to ferroptosis and alleviated OA progression. HIF-2α was identified as a central mediator in D-mannose-induced ferroptosis resistance of chondrocytes. Furthermore, overexpression of HIF-2α in chondrocytes by Ad-Epas1 intra-articular injection abolished the chondroprotective effect of D-mannose during OA progression and eliminated the role of D-mannose as a ferroptosis suppressor. CONCLUSIONS: D-mannose alleviates osteoarthritis progression by suppressing HIF-2α-mediated chondrocyte sensitivity to ferroptosis, indicating D-mannose to be a potential therapeutic strategy for ferroptosis-related diseases.

Novel Host Protein TBC1D16, a GTPase Activating Protein of Rab5C, Inhibits Prototype Foamy Virus Replication.

Prototype foamy virus (PFV) is a member of the oldest family of retroviruses and maintains lifelong latent infection in the host. The lifelong latent infection of PFV may be maintained by the restriction factors of viral replication in the host. However, the mechanisms involved in PFV latent infection are poorly understood. Here, we found that TBC1D16, a TBC domain-containing protein, is significantly down-regulated after PFV infection. Tre2/Bub2/Cdc16 (TBC) domain-containing proteins function as Rab GTPase-activating proteins (GAPs) and are participates in the progression of some diseases and many signaling pathways. However, whether TBC proteins are involved in PFV replication has not been determined. Here, we found that TBC1D16 is a novel antiviral protein that targets Rab5C to suppress PFV replication. Overexpression TBC1D16 inhibited the transcription and expression of Tas and Gag, and silencing TBC1D16 enhanced the PFV replication. Moreover, the highly conserved amino acid residues R494 and Q531 in the TBC domain of TBC1D16 were essential for inhibiting PFV replication. We also found that TBC1D16 promoted the production of PFV-induced IFN-ß and the transcription of downstream genes. These results suggest that TBC1D16 might be the first identified TBC proteins that inhibited PFV replication and the mechanism by which TBC1D16 inhibited PFV replication could provide new insights for PFV latency.