Apoptotic body-inspired nanotherapeutics efficiently attenuate osteoarthritis by targeting BRD4-regulated synovial macrophage polarization.

Bromodomain-containing protein 4 (BRD4) is the most well-studied BET protein that is important for the innate immune response. We recently revealed that targeting BRD4 triggers apoptosis in tumor-associated macrophages, but its role in synovial macrophages and joint inflammation is largely unknown. Herein, we demonstrated that BRD4 was highly expressed in the iNOS-positive M1 macrophages in the human and mouse osteoarthritis (OA) synovium, and conditional knockout of BRD4 in the myeloid lineage using Lyz2-cre; BRD4flox/flox mice significantly abolished anterior cruciate ligament transection (ACLT)-induced M1 macrophage accumulation and synovial inflammation. Accordingly, we successfully constructed apoptotic body-inspired phosphatidylserine-containing nanoliposomes (PSLs) loaded with the BRD4 inhibitor JQ1 to regulate inflammatory macrophages. JQ1-loaded PSLs (JQ1@PSLs) exhibited a higher cellular uptake by macrophages than fibroblast-like synoviocytes (FLSs) in vitro and in vivo, as well as the reduction in proinflammatory M1 macrophage polarization. Intra-articular injections of JQ1@PSLs showed prolonged retention within the joint, and remarkably reduced synovial inflammation and joint pain via suppressing M1 polarization accompanied by reduced TRPA1 expression by targeted inhibition of BRD4 in the macrophages, thus attenuating cartilage degradation during OA development. The results show that BRD4-inhibiting JQ1@PSLs can targeted-modulate macrophage polarization, which opens a new avenue for efficient OA therapy via a "Trojan horse".

Trim21 Regulates the Postnatal Development and Thermogenesis of Brown Adipose Tissue.

Brown adipose tissue undergoes rapid postnatal development to mature and plays a crucial role in thermoregulation and energy expenditure, which protects against cold and obesity. Herein, it is shown that the expression of Trim21 mRNA level of interscapular brown adipose tissue elevates after birth, and peaks at P14 (postnatal day 14). Trim21 depletion severely impairs the maturation of interscapular brown adipose tissue, decreases the expression of a series of thermogenic genes, and reduces energy expenditure. Consistently, the loss of Trim21 also leads to a suppression of white adipose tissue "browning", in response to cold exposure and a ß-adrenergic agonist, CL316,243. In addition, Trim21-/- mice are more prone to high-fat diet-induced obesity compared with the control littermates. Taken together, the study for the first time reveals a critical role of Trim21 in regulating iBAT postnatal development and thermogenesis.

From cells to organs: progress and potential in cartilaginous organoids research.

While cartilage tissue engineering has significantly improved the speed and quality of cartilage regeneration, the underlying metabolic mechanisms are complex, making research in this area lengthy and challenging. In the past decade, organoids have evolved rapidly as valuable research tools. Methods to create these advanced human cell models range from simple tissue culture techniques to complex bioengineering approaches. Cartilaginous organoids in part mimic the microphysiology of human cartilage and fill a gap in high-fidelity cartilage disease models to a certain extent. They hold great promise to elucidate the pathogenic mechanism of a diversity of cartilage diseases and prove crucial in the development of new drugs. This review will focus on the research progress of cartilaginous organoids and propose strategies for cartilaginous organoid construction, study directions, and future perspectives.

Trim21 depletion alleviates bone loss in osteoporosis via activation of YAP1/ß-catenin signaling.

Despite the diverse roles of tripartite motif (Trim)-containing proteins in the regulation of autophagy, the innate immune response, and cell differentiation, their roles in skeletal diseases are largely unknown. We recently demonstrated that Trim21 plays a crucial role in regulating osteoblast (OB) differentiation in osteosarcoma. However, how Trim21 contributes to skeletal degenerative disorders, including osteoporosis, remains unknown. First, human and mouse bone specimens were evaluated, and the results showed that Trim21 expression was significantly elevated in bone tissues obtained from osteoporosis patients. Next, we found that global knockout of the Trim21 gene (KO, Trim21-/-) resulted in higher bone mass compared to that of the control littermates. We further demonstrated that loss of Trim21 promoted bone formation by enhancing the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and elevating the activity of OBs; moreover, Trim21 depletion suppressed osteoclast (OC) formation of RAW264.7 cells. In addition, the differentiation of OCs from bone marrow-derived macrophages (BMMs) isolated from Trim21-/- and Ctsk-cre; Trim21f/f mice was largely compromised compared to that of the littermate control mice. Mechanistically, YAP1/ß-catenin signaling was identified and demonstrated to be required for the Trim21-mediated osteogenic differentiation of BMSCs. More importantly, the loss of Trim21 prevented ovariectomy (OVX)- and lipopolysaccharide (LPS)-induced bone loss in vivo by orchestrating the coupling of OBs and OCs through YAP1 signaling. Our current study demonstrated that Trim21 is crucial for regulating OB-mediated bone formation and OC-mediated bone resorption, thereby providing a basis for exploring Trim21 as a novel dual-targeting approach for treating osteoporosis and pathological bone loss.

Treatment of Morel-Lavallée Lesions (MLLs) with Mesh Incisions Combined with Quilting Sutures and Negative Pressure Wound Therapy (NPWT).

Purpose: The objective of this retrospective study was to evaluate the clinical effects of a novel treatment approach for Morel-Lavallée lesions (MLL) using a combination of suturing techniques and Negative Pressure Wound Therapy (NPWT) with mesh incisions. To summarize the clinical effects of a combination of suturing techniques and (Negative Pressure Wound Therapy) NPWT on the wall of Morel-Lavallée lesions (MLL) fibrotic pseudocapsules with mesh incisions in the treatment of MLLs. A retrospective analysis was performed on MLL patients from April 2017 to March 2021. Methods: This a retrospective case-control study and thirteen MLL patients were included in this retrospective analysis conducted between April 2017 and March 2021, who were treated with mesh incisions on the wall of the pseudocapsule, quilting suturing to degloved soft tissues, and NPWT. Physical examination, MRI, or ultrasound before surgery confirmed the diagnosis. Wound healing, secondary infection, recurrence, visual analog scale (VAS) scores before and after surgery, and skin and soft tissue condition were observed and evaluated. Results: The combination of mesh incisions, quilting sutures, and NPWT led to successful wound healing in 11 out of 13 cases without recurrent hematoma or secondary infection. Visual analog scale (VAS) scores significantly decreased after the operation, and the aesthetic and tactile qualities of the injured area improved. One case of skin and soft tissue necrosis infection before the operation, which healed after second-stage full-thickness skin grafting, 1 case healed after a dressing change, and the remaining 11 cases had wounds that healed by the first stage without secondary infection or recurrent hematoma formation. VAS scores decreased significantly after the operation, the appearance of the injured area was as expected, and the skin feel and elasticity recovered satisfactorily. Conclusion: The study demonstrates that the mesh incision technique, along with mattress sutures and NPWT, presents a feasible and effective approach for treating MLL with fibrotic pseudocapsules. This could shorten healing times, reduce risk of complications, and improve patient satisfaction.

Preliminary study of short-term outcomes and learning curves of robotic-assisted THA: comparison between closed platform robotic system and open platform robotic system.

BACKGROUND: Both closed platform and open platform robotic-assisted total hip arthroplasty (THA) have recently been recommended as a viable treatment option for achieving accurate positioning of components. Yet, limited studies paid attention to the differences between the closed platform robotic system and the open platform robotic system. Hence, this study aimed to investigate clinical outcomes, radiographic outcomes, complication rates and learning curve of two systems. MATERIALS AND METHODS: We retrospectively included 62 patients (31 closed robotic system and 31 open robotic system) who underwent THA between February 2021 and January 2023. The demographics, operating time, cup positioning, complications and hip Harris score were evaluated. Learning curves of operation time was conducted using cumulative sum (CUSUM) analysis. RESULTS: There were no differences in surgical time (76.7 ± 12.1 min vs. 72.3 ± 14.8 min), estimated blood loss (223.2 ± 13.2 ml vs. 216.9 ± 17 ml) and Harris Hip score (HHS) between closed platform robotic system and the open platform robotic system. The closed robotic system and the open robotic system were associated with a learning curve of 9 cases and 7 cases for surgical time respectively, based on the satisfying rate of Lewinnek's safe zone outliers (1/31, 96.8%) and no occurrence of complication. Both robotic systems had significant reduction in overall surgical time, the duration of acetabulum registration, and estimated blood loss between learning phase and proficiency phase. CONCLUSION: The authors suggest that the surgical outcomes and safe zone outlier rate of the open robotic-assisted THA were similar to those of the closed robotic-assisted THA. These two robotic-assisted are associated with comparable learning curves and both have the precise positioning of acetabular component. From learning phase to proficiency phase, the rate of positions within the safe zone differed only marginally (88.9-100% vs. 85.7-100%) based on a rather low number of patients. This is not a statistically significant difference. Therefore, we suggest that THA undergoing with the robotic-assisted system is the relatively useful way to achieve planned acetabular cup position so far.

Single-Cell RNA Sequencing Reveals Transcriptional Changes in the Cartilage of Subchondral Insufficiency Fracture of the Knee.

Purpose: Subchondral insufficiency fracture of the knee (SIFK) is a common cause of knee joint pain that mainly afflicts the elderly. Until now, how a sudden insufficiency fracture of subchondral bone affects the transcriptomic profiles of cartilage in SIFK and OA patients are largely unknown. Methods: Single-cell RNA sequencing (scRNA-seq) was used to identify various cell subsets and evaluate transcriptomic differences in cartilage of SIFK and OA patients. In addition, the above findings were confirmed by histological evaluation and immunohistochemical (IHC) staining. Results: We found that the transcriptomic profiles of cartilage in the SIFK patient was completely different from those of normal and OA patients. Accordingly, several novel cell clusters with activation of hypoxia and endochondral ossification signaling were identified in the SIFK cartilage. Chondrocyte trajectories analysis and IHC staining revealed that transcription factors including TCF4 were found to be highly up-regulated during the occurrence of SIFK, which might drive the reactive formation of cartilage and fibrous tissue and the activation of endochondral ossification. Conclusion: This is the first report to elucidate the transcriptomic alterations and distinct cell type subpopulations in the cartilage of SIFK and OA by the use of scRNA-seq, which provides a new insight in the understanding of the initiation and progression of SIFK.

Versatile Nano-PROTAC-Induced Epigenetic Reader Degradation for Efficient Lung Cancer Therapy.

Recent evidence has indicated that overexpression of the epigenetic reader bromodomain-containing protein 4 (BRD4) contributes to a poor prognosis of lung cancers, and the suppression of its expression promotes cell apoptosis and leads to tumor shrinkage. Proteolysis targeting chimera (PROTAC) has recently emerged as a promising therapeutic strategy with the capability to precisely degrade targeted proteins. Herein, a novel style of versatile nano-PROTAC (CREATE (CRV-LLC membrane/DS-PLGA/dBET6)) is developed, which is constructed by using a pH/GSH (glutathione)-responsive polymer (disulfide bond-linked poly(lactic-co-glycolic acid), DS-PLGA) to load BRD4-targeted PROTAC (dBET6), followed by the camouflage with engineered lung cancer cell membranes with dual targeting capability. Notably, CREATE remarkably confers simultaneous targeting ability to lung cancer cells and tumor-associated macrophages (TAMs). The pH/GSH-responsive design improves the release of dBET6 payload from nanoparticles to induce pronounced apoptosis of both cells, which synergistically inhibits tumor growth in both subcutaneous and orthotopic tumor-bearing mouse model. Furthermore, the efficient tumor inhibition is due to the direct elimination of lung cancer cells and TAMs, which remodels the tumor microenvironment. Taken together, the results elucidate the construction of a versatile nano-PROTAC enables to eliminate both lung cancer cells and TAMs, which opens a new avenue for efficient lung cancer therapy via PROTAC.

Effect of Diabetes Mellitus on Implant Osseointegration of Titanium Screws: An Animal Experimental Study.

OBJECTIVE: To explore the effect of diabetes mellitus (DM) on implant osseointegration of titanium screws. METHODS: Sixty rats were randomly divided into a DM group and a control group (each group, n = 30). DM group rats were injected with 1% Streptozotocin solution at 65 mg/kg to establish a DM model. Titanium screws were implanted into the rats' distal femurs in both groups. The rats were sacrificed for micro-CT scanning, micro-indentation, biomechanical detection, confocal Raman microspectroscopy, and histological and histomorphometric analysis at 4, 8, and 12 weeks post-implantation, respectively. Messenger RNA (mRNA) expression and protein expression of the related growth factors around the implant were analyzed using real-time polymerase chain reaction and Western blots. RESULTS: At 4, 8 and 12 weeks, micro-CT scanning, hematoxylin-eosin (HE) staining, Gieson's acid-magenta staining, and fluorescent labeled staining showed disorder in the bone tissue arrangement, a lack of new bone tissue, poor maturity and continuity, and poor trabecular bone parameters around the implant in the DM group. At 4, 8, and 12 weeks, the interfacial bone binding rate in the DM group was significantly lower (16.2% ± 4.8%, 25.7% ± 5.7%, 42.5% ± 5.8%, respectively) than that in the control group (23.6% ± 5.2%, 40.8% ± 6.3%, 64.2% ± 7.3%, respectively; P < 0.05). At 8 and 12 weeks, the elastic modulus (17.0 ± 1.8 and 15.1 ± 1.5 GPa, respectively) and trabecular bone hardness (571 ± 39 and 401 ± 37 MPa, respectively) in the DM group were significantly lower than the elastic modulus (23.4 ± 2.3 and 23.8 ± 1.8 GPa, respectively) and trabecular bone hardness (711 ± 45 and 719 ± 46 MPa, respectively) in the control group (P < 0.05). The maximum load required for the prosthesis pull-out experiment in the DM group at 4, 8, and 12 weeks (55.14 ± 6.74 N, 73.34 ± 8.43 N, and 83.45 ± 8.32 N, respectively) was significantly lower than that in the control group (77.45 ± 7.48 N, 93.28 ± 8.29 N, and 123.62 ± 9.43 N, respectively, P < 0.05). At 8 and 12 weeks, the mineral-to-collagen ratio in the DM group (6.56 % ± 1.35% and 4.45%± 1.25%, respectively) was significantly higher than that in the control group (5.31% ± 1.42% and 3.62% ± 1.33%, respectively, P < 0.05). At 12 weeks, mRNA and protein expression levels of bone morphogenetic protein 2, transforming growth factor-ß1, vascular endothelial growth factor, osteopontin, osteocalcin, and runt-related transcription factor 2 in the DM group were significantly lower than that in the control group. CONCLUSIONS: DM can negatively affect bone osseointegration, manifesting as disorder in bone tissue arrangement around the implant, a lack of new bone tissue, poor maturity and continuity, poor trabecular bone parameters and lower expression of the related growth factors.

Senescent skeletal cells cross-talk with synovial cells plays a key role in the pathogenesis of osteoarthritis.

Osteoarthritis (OA) has been recognized as an age-related degenerative disease commonly seen in the elderly that affects the whole "organ" including cartilage, subchondral bone, synovium, and muscles. An increasing number of studies have suggested that the accumulation of senescent cells triggering by various stresses in the local joint contributes to the pathogenesis of age-related diseases including OA. In this review, we mainly focus on the role of the senescent skeletal cells (chondrocytes, osteoblasts, osteoclasts, osteocyte, and muscle cells) in initiating the development and progression of OA alone or through cross-talk with the macrophages/synovial cells. Accordingly, we summarize the current OA-targeted therapies based on the abovementioned theory, e.g., by eliminating senescent skeletal cells and/or inhibiting the senescence-associated secretory phenotype (SASP) that drives senescence. Furthermore, the existing animal models for the study of OA from the perspective of senescence are highlighted to fill the gap between basic research and clinical applications. Overall, in this review, we systematically assess the current understanding of cellular senescence in OA, which in turn might shed light on the stratified OA treatments.

YAP/miR-524-5p axis negatively regulates TXNIP expression to promote chondrosarcoma cell growth.

Chondrosarcoma (CHS) is the second most common bone malignant tumor and currently has limited treatment options. We have recently demonstrated that thioredoxin interacting protein (TXNIP) plays a crucial role in the oncogenesis of bone sarcoma, yet its implication in CHS is underdetermined. In the present study, we first found that knockdown of TXNIP promotes the proliferation of CHS cell largely through increasing their glycolytic metabolism, which is well-known as Warburg effect for providing energy. Consistent with our previous report that YAP is fundamental for CHS cell growth, herein we revealed that YAP functioned as an upstream molecule of TXNIP, and that YAP negatively regulated TXNIP mRNA and protein expression both in vitro and in vivo. Mechanistically, although knockdown of YAP upregulated both the nuclear and cytoplasmic TXNIP expression, we did not observe any obvious interaction between YAP and TXNIP; instead, miRNA-524-5p was demonstrated to be required for YAP-regulated TXNIP expression and thus controlling CHS cell growth. Together, our study reveals that TXNIP is a tumor suppressor in terms of CHS, and that the YAP/miRNA-524-5p/TXNIP signaling axis may provide a novel clue for CHS targeted therapy.

Outcomes of dual mobility articulation total hip arthroplasty in ipsilateral residual poliomyelitis.

BACKGROUND: Patients with poliomyelitis underwent total hip arthroplasty (THA) are known to be at higher risk of dislocation on account of muscular atrophy. This study aimed to investigate clinical outcomes, radiographic outcomes, complication rates, and survivorship of dual mobility THA in displaced femoral neck fractures of elderly with poliomyelitis. MATERIALS AND METHODS: We retrospectively included 17 patients (17 hips) with residual poliomyelitis who underwent THA with dual mobility articulation. Clinical outcomes were assessed with the visual analog scale (VAS) pain score, Oxford hip score, and University of California Los Angeles activity (UCLA) score. Radiographic outcomes were examined by radiographs. Complications and re-operations following THA were recorded. RESULTS: The mean follow-up period was 77.05 months. The mean VAS, Oxford hip score, and UCLA score were improved significantly. In all but one patient, no complications were occurred. Re-operation was carried out in one patient due to posterior dislocation. The Kaplan-Meier survivorship with an end point of re-operation for any reason was 94.1%. CONCLUSIONS: THA with dual mobility system is proved to be effective in strengthening stability and reducing the risk of dislocation, which is suitable for patients with neuromuscular disease. Hence, in elderly with residual poliomyelitis, dual mobility THA is a valid choice as a treatment for displaced femoral neck fractures.

The role of routine postoperative laboratory tests following hip hemiarthroplasty for an elderly femoral neck fracture.

BACKGROUND: Performing postoperative laboratory tests following joint arthroplasty is a regular practice. However, the role of routine postoperative laboratory tests in primary hip arthroplasty is currently in doubt. This study aimed to assess the role of routine postoperative laboratory tests for femoral neck fractures in elderly patients who underwent hip hemiarthroplasty and to evaluate the risk factors for postoperative laboratory testing abnormalities and related interventions. METHODS: This retrospective study reviewed 735 consecutive patients with femoral neck fractures (FNFs) who underwent hip hemiarthroplasty at a single tertiary academic organization. Patient characteristic features and laboratory testing values were recorded. Logistic regression models were calculated to identify risk factors. RESULTS: A total of 321 elderly patients (> 75 years of age) were ultimately enrolled for analysis. Abnormal postoperative laboratory tests were found in 265 patients (82.6%). Only a minority of the included patients (7.5%) needed medical intervention to treat postoperative laboratory testing abnormalities. Multivariate logistic regression analysis reported that a higher Charlson comorbidity index (CCI) (P = 0.03), abnormal preoperative haemoglobin level (P < 0.01), higher intraoperative blood loss (P < 0.01) and less frequent tranexamic acid use (P = 0.05) were risk factors for abnormal postoperative laboratory tests. Furthermore, a higher CCI has been identified as a risk factor for patients needing clinical interventions related to laboratory abnormalities. CONCLUSIONS: Because 92.5% of laboratory tests did not influence postoperative management, the authors suggest that routine laboratory tests after hip hemiarthroplasty for FNFs are less instructive for the majority of elderly patients. Nevertheless, for patients with identified risk factors, postoperative laboratory tests are still required to identify the abnormalities that need to be managed.

Arthroscopic Hip Surgery versus Conservative Therapy on Femoroacetabular Impingement Syndrome: A Meta-Analysis of RCTs.

To determine the outcome and differences between arthroscopic hip surgery and conservative therapy in patients suffering from femoroacetabular impingement syndrome, we searched articles from PubMed, Embase, Cochrane, Web of Science and Clinicaltrials.gov using a Boolean search algorithm. Only randomized controlled trials comparing arthroscopic hip surgery and conservative therapy were included in this meta-analysis of femoroacetabular impingement syndrome management. Two authors determined eligibility, extracted the needed data and assessed the risk of bias of eligible studies independently. Then we meta-analyzed three articles to assess pooled estimate size (ES) and 95% confidence interval for Hip Outcome Score of activities of daily living (HOS ADL subscale), Hip Outcome Score sport (HOS sports subscale) and International Hip Outcome Tool (iHOT-33) analyses were performed by using STATA version 14.0 MP (STATA, College Station, TX, USA) with the principal summary measures are mean between group difference, sample size, and standard deviation. We collected 52 articles in total after removing duplicates and screened by titles and abstracts. A total of three RCTs were included finally. There was definite evidence of additional benefit of arthroscopic hip surgery against conservative therapy in the field of improving quality of life (three trials, 575 participants, ES = 2.109, 95% CI: 1.373 to 2.845, I2  = 42.8%, P = 0.000) and activity of daily living (two trials, 262 participants, ES = 9.220, 95% CI: 5.931 to 12.508, I2  = 16.5%, P = 0.000). However, no significant difference could be seen in sports function improvement (two trials, ES = 7.562, 95% CI: -2.957 to 18.082, I2  = 60.1%, P = 0.159). In conclusion, this meta-analysis suggests that arthroscopic hip surgery provided essential benefit compared with conservative therapy in improving activity of daily living and quality of life.

Diabetes mellitus accelerates the progression of osteoarthritis in streptozotocin-induced diabetic mice by deteriorating bone microarchitecture, bone mineral composition, and bone strength of subchondral bone.

BACKGROUND: The purpose of this study was to develop an optimal diabetes-osteoarthritis (DM-OA) mouse model to validate that diabetes aggravates osteoarthritis (OA) and to evaluate the microarchitecture, chemical composition, and biomechanical properties of subchondral bone (SB) as a consequence of the DM-OA-induced damage induced. METHODS: Mice were randomly divided into three groups: DM-OA group, OA group, and sham group. Blood glucose levels, body weight, and food intake of all animals were recorded. Serum calcium (Ca) and osteocalcin (OCN) levels were compared in the three groups. The messenger ribonucleic acid (mRNA) and protein expression of key regulators for bone metabolism were detected. A semi-quantitative grading system [Osteoarthritis Research Society International (OARSI)] was used to evaluate cartilage and SB degeneration. Microspectroscopy, microindentations, micro-computed tomography (CT) imaging, and fracture load of compression testing were also used to evaluate trabecular SB properties. RESULTS: Glycemic monitoring and pancreas pathological results indicated stable high blood glucose and massive destruction of pancreas and islet cells in the DM-OA group. Serum levels of bone specific alkaline phosphatase (ALP-B) and tartrate-resistant acid phosphatase 5b (TRACP-5b) in the DM-group were higher than those of the other two groups while levels of serum Ca and OCN were lower. Meanwhile, the protein and mRNA expression of osteoblast-specific biomarkers [osteoprotegerin/receptor activator of nuclear factor kappa-B ligand (OPG/RANKL) ratio, collagen type I (COL-I), Runt-related transcription factor 2 (RUNX-2), OCN] were suppressed, and osteoclast-specific biomarkers [sclerostin (SOST)] was elevated in the DM-OA group. The mineral-to-collagen ratio, microindentation elastic modulus, hardness, micro-architectural parameters, bone mineral density, and fracture load of SB trabecular bone of the DM-OA group joint were lower than those of the other two groups. On the other hand, The OARSI score, trabecular spacing, and structural model index of the DM-OA group joint were higher than those of the other two groups. CONCLUSIONS: The glycemic and pancreatic pathological results indicated that the DM-OA model was a simple and reliable model induced by streptozotocin (STZ) and surgery. The results revealed the mechanisms through which diabetes accelerates OA; that is, by damaging and deteriorating the functions of SB, including its microarchitecture, chemical composition, and biomechanical properties.

Sequential targeting of YAP1 and p21 enhances the elimination of senescent cells induced by the BET inhibitor JQ1.

Chondrosarcoma (CHS) is the second most common bone malignancy with limited therapeutic approaches. Our previous study has found that Yes associated protein 1 (YAP1) is downregulated in CHS cells treated with bromodomain and extraterminal domain (BET) inhibitor JQ1. However, the precise role of YAP1 in CHS is largely unknown. Herein, we found that YAP1 expression was upregulated in CHS tissues, and positively correlated with its grading score. Loss of YAP1 inhibited CHS proliferation and induced cellular senescence, while expression of YAP1 mutants revealed YAP1/TEA domain family member (TEAD)-dependent negative regulation of p21 and subsequent cellular senescence. These results were validated by in vivo experiments using stable shYAP1 cell lines. Mechanistically, negative regulation of p21 by YAP1 occurred post-transcriptionally via Dicer-regulated miRNA networks, specifically, the miR-17 family. Furthermore, we demonstrated that sequential targeting of YAP1 and p21 enhanced the elimination of JQ1-induced senescent cells in a Bcl-2-like 1 (Bcl-XL)/Caspase-3 dependent manner. Altogether, we unveil a novel role of YAP1 signaling in mediating CHS cell senescence and propose a one-two punch approach that sequentially targets the YAP1/p21 axis to eliminate senescent cells.

Visualization of GLUT1 Trafficking in Live Cancer Cells by the Use of a Dual-Fluorescence Reporter.

Glucose metabolism is an essential process for energy production and cell survival for both normal and abnormal cellular metabolism. Several glucose transporter/solute carrier 2A (GLUT/SLC2A) superfamily members, including glucose transporter 1 (GLUT1), have been shown to mediate the cellular uptake of glucose in diverse cell types. GLUT1-mediated glucose uptake is a transient and rapid process; thus, the real-time monitoring of GLUT1 trafficking is pivotal for a better understanding of GLUT1 expression and GLUT1-dependent glucose uptake. In the present study, we established a rapid and effective method to visualize the trafficking of GLUT1 between the plasma membrane (PM) and endolysosomal system in live cells using an mCherry-EGFP-GLUT1 tandem fluorescence tracing system. We found that GLUT1 localized at the PM exhibited both red (mCherry) and green (EGFP) fluorescence (yellow when overlapping). However, a significant increase in red punctate fluorescence (mCherry is resistant to acidic pH), but not green fluorescence (EGFP is quenched by acidic pH), was observed upon glucose deprivation, indicating that the mCherry-EGFP-GLUT1 functional protein was trafficked to the acidic endolysosomal system. Besides, we were able to calculate the relative ratio of mCherry to EGFP by quantification of the translocation coefficient, which can be used as a readout for GLUT1 internalization and subsequent lysosomal degradation. Two mutants, mCherry-EGFP-GLUT1-S226D and mCherry-EGFP-GLUT1-ΔC4, were also constructed, which indirectly confirmed the specificity of mCherry-EGFP-GLUT1 for monitoring GLUT1 trafficking. By using a series of endosomal (Rab5, Rab7, and Rab11) and lysosomal markers, we were able to define a model of GLUT1 trafficking in live cells in which upon glucose deprivation, GLUT1 dissociates from the PM and experiences a pH gradient from 6.8-6.1 in the early endosomes to 6.0-4.8 in the late endosomes and finally pH 4.5 in lysosomes, which is appropriate for degradation. In addition, our proof-of-concept study indicated that the pmCherry-EGFP-GLUT1 tracing system can accurately reflect endogenous changes in GLUT1 in response to treatment with the small molecule, andrographolide. Since targeting GLUT1 expression and GLUT1-dependent glucose metabolism is a promising therapeutic strategy for diverse types of cancers and certain other glucose addiction diseases, our study herein indicates that pmCherry-EGFP-GLUT1 can be utilized as a biosensor for GLUT1-dependent functional studies and potential small molecule screening.

The multiple roles of Thy-1 in cell differentiation and regeneration.

Thy-1 is a 25-37 kDa glycophosphatidylinositol (GPI)-anchored cell surface protein that was discovered more than 50 years ago. Recent findings have suggested that Thy-1 is expressed on thymocytes, mesenchymal stem cells (MSCs), cancer stem cells, hematopoietic stem cells, fibroblasts, myofibroblasts, endothelial cells, neuronal smooth muscle cells, and pan T cells. Thy-1 plays vital roles in cell migration, adhesion, differentiation, transdifferentiation, apoptosis, mechanotransduction, and cell division, which in turn are involved in tumor development, pulmonary fibrosis, neurite outgrowth, and T cell activation. Studies have increasingly indicated a significant role of Thy-1 in cell differentiation and regeneration. However, despite recent research, many questions remain regarding the roles of Thy-1 in cell differentiation and regeneration. This review aimed to summarize the roles of Thy-1 in cell differentiation and regeneration. Furthermore, since Thy-1 is an outer leaflet membrane protein anchored by GPI, we attempted to address how Thy-1 regulates intracellular pathways through cis and trans signals. Due to the complexity and mystery surrounding the issue, we also summarized the Thy-1-related pathways in different biological processes, and this might provide novel insights in the field of cell differentiation and regeneration.

Gap balancing versus measured resection in primary total knee arthroplasty: A retrospective cohort study protocol.

BACKGROUND: Recently, controversy still exists regarding the clinical effects of measured resection or gap-balancing technique in total knee arthroplasty (TKA). The objective of this retrospective study was to compare the clinical outcomes of conventional measured resection technique and computer-assisted gap-balancing technique in TKA. METHODS: Strengthening the Reporting of Observational studies in Epidemiology checklist. Patients underwent primary TKA by a single surgeon between 2014 and 2016 were reviewed. This study was approved by the institutional review board in our hospital and was registered in the Research Registry. Outcome measures included surgical time, intraoperative complications, patient satisfaction, Oxford Knee Score, range of motion, postoperative complications, and revision. RESULTS: This study had limited inclusion and exclusion criteria and a well-controlled intervention. CONCLUSION: We were able to directly compare the outcomes of measured resection versus gap-balancing techniques and might reveal a better technique in TKA. TRIAL REGISTRATION: This study protocol was registered in Research Registry (researchregistry5441).

Hemiarthroplasty compared with internal fixation for treatment of nondisplaced femoral neck fractures in elderly patients: a retrospective study.

INTRODUCTION: Internal fixation (IF) with cannulated screws is the most widely accepted operation method for nondisplaced femoral neck fractures (FNFs) in elderly patients. However, there were higher rate of reoperation, severe complications and poorer functional outcomes reported in these patients treated with IF. The purpose of this research is to compare the prognosis, complications, reoperation and mortality of bipolar hemiarthroplasty (HA) with IF of cannulated screws in elderly patients. METHODS: All elderly patients (>75 years of age) with nondisplaced FNFs from January 2010 to December 2015 at our institution were included in this study. Patients treated with HA and IF with cannulated screws were compared. Outcome measures included the surgical complications, perioperative parameters, hip joint function, reoperation and mortality. RESULTS: The blood loss of HA group (150.0 ± 55.1 mL) was statistically more than IF group (40.5 ± 15.7 mL, p = 0.001). However, the blood transfusion rate was similar between two groups (p = 0.102). At the last follow-up, there were total 14 (34.1%) severe surgical complications in the IF group, compared to 9 (10.1%) in the HA group (P = 0.001). No difference was detected between two groups with respect to the HHS and VAS at the last follow-up. Compared with the HA group, the IF group had much more reoperation in the follow up period (p = 0.001). There was no statistically differences of mortality rate between HA group (39.3%, 35/89) and IF group (34.1%, 14/41) (p=0.571). CONCLUSIONS: As a treatment option for nondisplaced intracapsular FNFs in elderly patients, HA showed the merits of a less surgical complications and less reoperations, while IF demonstrated a shorter surgical time and less intraoperative blood loss. Meanwhile, there was no significant difference in the hip joint function and mortality rate in midterm follow-up. Further evaluation with a longer follow-up is recommended to strengthen these findings.