Age-Related Decrease in Pellino-1 Expression Contributes to Osteoclast-Mediated Bone Loss.

Aging-related bone loss is driven by various biological factors, such as imbalanced bone metabolism from decreased osteoblast and increased osteoclast activities. Various transcriptional and post-transcriptional factors increase osteoclast activity with aging; however, studies regarding the post-translational regulators of osteoclast activity are still limited. The ubiquitin E3 ligase Pellino-1 is a well-known post-translational regulator of inflammation. However, how Pellino-1 expression regulation affects osteoclast differentiation remains unclear. This study determined that Pellino-1 levels are reduced in bone marrow monocytes (BMMs) from 40-week-old mice compared to 4-week-old mice. Interestingly, conditional Knockout (cKO) of Pellino-1 in 6-week-old mice resulted in decreased bone mass, reduced body size, and lower weight than in Pellino-1 floxed mice; however, these differences are not observed in 20-week-old mice. The increased number of tartrate-resistant acid phosphatase (TRAP)-positive cells and serum levels of C-terminal telopeptides of type I collagen, a marker of bone resorption, in 6-week-old Pellino-1 cKO mice implied a connection between Pellino-1 and the osteoclast population. Enhanced TRAP activity and upregulation of osteoclast genes in BMMs from the cKO mice indicate that Pellino-1 deletion affects osteoclast differentiation, leading to decreased bone mass and heightened osteoclast activity. Thus, targeting Pellino-1 could be a potential gene therapy for managing and preventing osteoporosis.

Robotic-assisted foot and ankle surgery: a review of the present status and the future.

The surgical application of robotics has increased significantly since its first application in 1985 for a brain biopsy acquisition. Robotic-assisted surgery has been one of the viable options in various surgical areas, and also in orthopaedic surgery. Robotic-assisted orthopaedic surgery has gained popularity as a mean of improving accuracy, reducing complications and achieving better patient satisfaction. Numerous clinical research studies have demonstrated advantages of robotic-assisted orthopaedic surgery, however, most of that researches were about the total knee arthroplasty, total hip arthroplasty and spine surgery. The application of robotic technology in foot and ankle surgery is in a very nascent stage. Furthermore, there has been little research on intraoperative use of robotics in foot and ankle surgery in literature. A review of previous preclinical studies in foot and ankle robotics and clinical research studies in various fields of robot-assisted orthopaedic surgery shows that its potential application and benefits over conventional techniques, such as total ankle arthroplasty, minimally invasive surgery for foot and ankle trauma or other corrective procedure, and intraoperative biomechanical testing. More studies on practical application of robotic technology to surgical procedure in the field of foot and ankle surgery are needed to confirm its clinical usefulness and cost effectiveness.

Promoting angiogenesis and diabetic wound healing through delivery of protein transduction domain-BMP2 formulated nanoparticles with hydrogel.

Decreased angiogenesis contributes to delayed wound healing in diabetic patients. Recombinant human bone morphogenetic protein-2 (rhBMP2) has also been demonstrated to promote angiogenesis. However, the short half-lives of soluble growth factors, including rhBMP2, limit their use in wound-healing applications. To address this limitation, we propose a novel delivery model using a protein transduction domain (PTD) formulated in a lipid nanoparticle (LNP). We aimed to determine whether a gelatin hydrogel dressing loaded with LNP-formulated PTD-BMP2 (LNP-PTD-BMP2) could enhance the angiogenic function of BMP2 and improve diabetic wound healing. In vitro, compared to the control and rhBMP2, LNP-PTD-BMP2 induced greater tube formation in human umbilical vein endothelial cells and increased the cell recruitment capacity of HaCaT cells. We inflicted large, full-thickness back skin wounds on streptozotocin-induced diabetic mice and applied gelatin hydrogel (GH) cross-linked by microbial transglutaminase containing rhBMP2, LNP-PTD-BMP2, or a control to these wounds. Wounds treated with LNP-PTD-BMP2-loaded GH exhibited enhanced wound closure, increased re-epithelialization rates, and higher collagen deposition than those with other treatments. Moreover, LNP-PTD-BMP2-loaded GH treatment resulted in more CD31- and α-SMA-positive cells, indicating greater neovascularization capacity than rhBMP2-loaded GH or GH treatments alone. Furthermore, in vivo near-infrared fluorescence revealed that LNP-PTD-BMP2 has a longer half-life than rhBMP2 and that BMP2 localizes around wounds. In conclusion, LNP-PTD-BMP2-loaded GH is a viable treatment option for diabetic wounds.

Minimally Invasive Transverse Distal Metatarsal Osteotomy (MITO) for Hallux Valgus Correction: Early Outcomes of Mild to Moderate vs Severe Deformities.

BACKGROUND: We compared the radiological and clinical outcomes of mild to moderate and severe hallux valgus (HV) treated with minimally invasive distal metatarsal transverse osteotomy (MITO) performed by a single surgeon. METHODS: Eighty-four patients who underwent MITO between May 2018 and March 2020 were recruited and followed for at least 24 months. The severe group was defined as having a preoperative hallux valgus angle (HVA) >40 degrees or preoperative first-to-second intermetatarsal angle (1-2 IMA) >16 degrees; the mild to moderate group was defined as having an HVA <40 degrees and a 1-2 IMA <16 degrees. Pre- and postoperative measurements of the HVA, 1-2 IMA, distal metatarsal articular angle, and tibial sesamoid position were obtained. The visual analog scale for pain, the Foot and Ankle Outcome Score, and the Medical Outcomes Study Short Form Health Survey-36 physical component summary were used to assess clinical outcomes. RESULTS: A total of 116 feet were included in this study and median follow-up period of 29.0 months (range, 24-52 months). Both groups showed significant improvements in all radiologic parameters postoperatively, with the degrees of correction greater in the severe group than in the mild to moderate group. All clinical scores improved significantly from the preoperative to the last follow-up visit. Final clinical outcomes and degrees of improvement were comparable in both groups. CONCLUSION: This study showed that short-term radiographic results for patients with either mild to moderate or severe HV treated with MITO were favorable. Overall clinical outcomes were comparable to those of conventional treatments. In this series, we found MITO with screw fixation to be a satisfactory surgical option for patients with mild to severe HV deformities. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Inhibiting the cytosolic function of CXXC5 accelerates diabetic wound healing by enhancing angiogenesis and skin repair.

Diabetic wound healing, including diabetic foot ulcer (DFU), is a serious complication of diabetes. Considering the complexity of DFU development, the identification of a factor that mediates multiple pathogeneses is important for treatment. In this study, we found that CXXC-type zinc finger protein 5 (CXXC5), a negative regulator of the Wnt/ß-catenin pathway, was overexpressed with suppression of the Wnt/ß-catenin pathway and its target genes involved in wound healing and angiogenesis in the wound tissues of DFU patients and diabetes-induced model mice. KY19334, a small molecule that activates the Wnt/ß-catenin pathway by inhibiting the CXXC5-Dvl interaction, accelerated wound healing in diabetic mice. The enhancement of diabetic wound healing could be achieved by restoring the suppressed Wnt/ß-catenin signaling and subsequently inducing its target genes. Moreover, KY19334 induced angiogenesis in hindlimb ischemia model mice. Overall, these findings revealed that restorative activation of Wnt/ß-catenin signaling by inhibiting the function of cytosolic CXXC5 could be a therapeutic approach for treating DFUs.

Medial Reduction in Sesamoid Position after Hallux Valgus Correction Surgery Showed Better Outcome in S.E.R.I. Osteotomy than DCMO.

BACKGROUND: The purpose of the present study was to compare the degree of sesamoid reduction after hallux valgus correction between distal chevron metatarsal osteotomy (DCMO) and S.E.R.I. (simple, effective, rapid, and inexpensive) osteotomy, and to analyze the effects on the recurrence of hallux valgus. METHODS: We retrospectively analyzed the foot radiographs of 60 feet (30 DCMO and 30 SERI) treated for hallux valgus from August 2013 to July 2017. Radiographic assessments were performed preoperatively, at early follow-up (at a mean of 3.1 months) and at the most recent follow-up (at a mean of 16.7 months). The location of the medial sesamoid was classified into seven stages, in accordance with the method described by Hardy and Clapham; stage IV or less was defined as the normal position for the medial sesamoid, and stage V or greater was defined as lateral displacement of the sesamoid. The pre- and post-operative hallux valgus angle, 1-2 intermetatarsal angle, and sesamoid position were compared between the two groups. RESULTS: The mean follow-up period was 18.4 (12-36) months in the DCMO group and 15.0 (12-36) months in the S.E.R.I. group (p = 0.108). The radiologic results showed that the hallux valgus angles were not significantly different between the two groups preoperatively and at the early follow-up: preoperatively, they were 28.8 ± 7.7 in the DCMO group and 32.6 ± 9.5 in the S.E.R.I. group (p = 0.101), and they were 10.4 ± 4.0 and 8.7 ± 5.0 (p = 0.148) at the early follow-up, respectively. However, at the most recent follow-up, the DCMO group (13.9 ± 5.6) showed significantly higher hallux valgus angles than the S.E.R.I. group (10.4 ± 6.4, p = 0.030), and there were no differences between the recurrence of hallux valgus in the DCMO group (13%)and that in the S.E.R.I. group (10%) (p = 0.553). There were no significant differences in the 1-2 intermetatarsal angles between the two groups at the early follow-up (6.1 ± 2.5 vs. 4.8 ± 3.1, p = 0.082) and at the most recent follow-up (7.3 ± 2.9 vs. 6.6 ± 3.5, p = 0.408). After hallux-valgus-correction surgery, the stage change of the tibia sesamoid position from the preoperative stage to the initial follow-up was significantly larger in the S.E.R.I. group (-4.4 ± 1.4) than in the DCMO group (-3.4 ± 1.1) (p = 0.003); the changes from the preoperative stage to the last follow-up were also significantly larger in the SERI group (-3.3 ± 1.7) than in the DCMO group (-2.4 ± 1.5) (p = 0.028); however, the changes from the initial follow-up to the last follow-up showed no significant differences between the two groups (+1.0 ± 1.1 in the DCMO group vs. +1.1 ± 1.2 in the S.E.R.I. group) (p = 0.822). The medial sesamoid was laterally subluxated in all the preoperative cases in the DCMO and S.E.R.I. groups. The lateral subluxation of the tibia sesamoid was more frequently observed in the DCMO group (four cases, 13%) than in the S.E.R.I. group (0 cases, 0%) (p = 0.038) at the early follow-up. CONCLUSION: In conclusion, our results demonstrated that the S.E.R.I. procedure is superior to DCMO in decreasing the hallux valgus angle and showed that the early post-operative reduction in the sesamoids can be a risk factor for the recurrence of hallux valgus.

Schnurri-3 inhibition suppresses bone and joint damage in models of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to systemic and articular bone loss by activating bone resorption and suppressing bone formation. Despite current therapeutic agents, inflammation-induced bone loss in RA continues to be a significant clinical problem due to joint deformity and lack of articular and systemic bone repair. Here, we identify the suppressor of bone formation, Schnurri-3 (SHN3), as a potential target to prevent bone loss in RA. SHN3 expression in osteoblast-lineage cells is induced by proinflammatory cytokines. Germline deletion or conditional deletion of Shn3 in osteoblasts limits articular bone erosion and systemic bone loss in mouse models of RA. Similarly, silencing of SHN3 expression in these RA models using systemic delivery of a bone-targeting recombinant adenoassociated virus protects against inflammation-induced bone loss. In osteoblasts, TNF activates SHN3 via ERK MAPK-mediated phosphorylation and, in turn, phosphorylated SHN3 inhibits WNT/ß-catenin signaling and up-regulates RANKL expression. Accordingly, knock-in of a mutation in Shn3 that fails to bind ERK MAPK promotes bone formation in mice overexpressing human TNF due to augmented WNT/ß-catenin signaling. Remarkably, Shn3-deficient osteoblasts are not only resistant to TNF-induced suppression of osteogenesis, but also down-regulate osteoclast development. Collectively, these findings demonstrate SHN3 inhibition as a promising approach to limit bone loss and promote bone repair in RA.

Downregulation of the RNA-binding protein PUM2 facilitates MSC-driven bone regeneration and prevents OVX-induced bone loss.

BACKGROUND: Although mRNA dysregulation can induce changes in mesenchymal stem cell (MSC) homeostasis, the mechanisms by which post-transcriptional regulation influences MSC differentiation potential remain understudied. PUMILIO2 (PUM2) represses translation by binding target mRNAs in a sequence-specific manner. METHODS: In vitro osteogenic differentiation assays were conducted using human bone marrow-derived MSCs. Alkaline phosphatase and alizarin red S staining were used to evaluate the osteogenic potential of MSCs. A rat xenograft model featuring a calvarial defect to examine effects of MSC-driven bone regeneration. RNA-immunoprecipitation (RNA-IP) assay was used to determine the interaction between PUM2 protein and Distal-Less Homeobox 5 (DLX5) mRNA. Ovariectomized (OVX) mice were employed to evaluate the effect of gene therapy for postmenopausal osteoporosis. RESULTS: Here, we elucidated the molecular mechanism of PUM2 in MSC osteogenesis and evaluated the applicability of PUM2 knockdown (KD) as a potential cell-based or gene therapy. PUM2 level was downregulated during MSC osteogenic differentiation, and PUM2 KD enhanced MSC osteogenic potential. Following PUM2 KD, MSCs were transplanted onto calvarial defects in 12-week-old rats; after 8 weeks, transplanted MSCs promoted bone regeneration. PUM2 KD upregulated the expression of DLX5 mRNA and protein and the reporter activity of its 3'-untranslated region. RNA-IP revealed direct binding of PUM2 to DLX5 mRNA. We then evaluated the potential of adeno-associated virus serotype 9 (AAV9)-siPum2 as a gene therapy for osteoporosis in OVX mice. CONCLUSION: Our findings suggest a novel role for PUM2 in MSC osteogenesis and highlight the potential of PUM2 KD-MSCs in bone regeneration. Additionally, we showed that AAV9-siPum2 is a potential gene therapy for osteoporosis.

RUNX2 stabilization by long non-coding RNAs contributes to hypertrophic changes in human chondrocytes.

Background: Chondrocyte hypertrophy has been implicated in endochondral ossification and osteoarthritis (OA). In OA, hypertrophic chondrocytes contribute to the destruction and focal calcification of the joint cartilage. Although studies in this field have remarkably developed the modulation of joint inflammation using gene therapy and regeneration of damaged articular cartilage using cell therapy, studies that can modulate or prevent hypertrophic changes in articular chondrocytes are still lacking. Methods: In vitro hypertrophic differentiation and inflammation assays were conducted using human normal chondrocyte cell lines, TC28a2 cells. Human cartilage tissues and primary articular chondrocytes were obtained from OA patients undergoing total knee arthroplasty. Long non-coding RNAs (lncRNAs), LINC02035 and LOC100130207, were selected through RNA-sequencing analysis using RNAs extracted from TC28a2 cells cultured in hypertrophic medium. The regulatory mechanism was evaluated using western blotting, real-time quantitative polymerase chain reaction, osteocalcin reporter assay, RNA-immunoprecipitation (RNA-IP), RNA-in situ hybridization, and IP. Results: LncRNAs are crucial regulators of various biological processes. In this study, we identified two important lncRNAs, LINC02035 and LOC100130207, which play important roles in hypertrophic changes in normal chondrocytes, through RNA sequencing. Interestingly, the expression level of RUNX2, a master regulator of chondrocyte hypertrophy, was regulated at the post-translational level during hypertrophic differentiation of the normal human chondrocyte cell line, TC28a2. RNA-immunoprecipitation proved the potential interaction between RUNX2 protein and both lncRNAs. Knockdown (KD) of LINC02035 or LOC100130207 promoted ubiquitin-mediated proteasomal degradation of RUNX2 and prevented hypertrophic differentiation of normal chondrocyte cell lines, whereas overexpression of both lncRNAs stabilized RUNX2 protein and generated hypertrophic changes. Furthermore, the KD of the two lncRNAs mitigated the destruction of important cartilage matrix proteins, COL2A1 and ACAN, by hypertrophic differentiation or inflammatory conditions. We also confirmed that the phenotypic changes raised by the two lncRNAs could be rescued by modulating RUNX2 expression. In addition, the KD of these two lncRNAs suppressed hypertrophic changes during chondrogenic differentiation of mesenchymal stem cells. Conclusion: Therefore, this study suggests that LINC02035 and LOC100130207 contribute to hypertrophic changes in normal chondrocytes by regulating RUNX2, suggesting that these two novel lncRNAs could be potential therapeutic targets for delaying or preventing OA development, especially for preventing chondrocyte hypertrophy.

WNT-modulating gene silencers as a gene therapy for osteoporosis, bone fracture, and critical-sized bone defects.

Treating osteoporosis and associated bone fractures remains challenging for drug development in part due to potential off-target side effects and the requirement for long-term treatment. Here, we identify recombinant adeno-associated virus (rAAV)-mediated gene therapy as a complementary approach to existing osteoporosis therapies, offering long-lasting targeting of multiple targets and/or previously undruggable intracellular non-enzymatic targets. Treatment with a bone-targeted rAAV carrying artificial microRNAs (miRNAs) silenced the expression of WNT antagonists, schnurri-3 (SHN3), and sclerostin (SOST), and enhanced WNT/ß-catenin signaling, osteoblast function, and bone formation. A single systemic administration of rAAVs effectively reversed bone loss in both postmenopausal and senile osteoporosis. Moreover, the healing of bone fracture and critical-sized bone defects was also markedly improved by systemic injection or transplantation of AAV-bound allograft bone to the osteotomy sites. Collectively, our data demonstrate the clinical potential of bone-specific gene silencers to treat skeletal disorders of low bone mass and impaired fracture repair.

Deubiquitinating Enzyme USP7 Is Required for Self-Renewal and Multipotency of Human Bone Marrow-Derived Mesenchymal Stromal Cells.

Ubiquitin-specific protease 7 (USP7) is highly expressed in a variety of malignant tumors. However, the role of USP7 in regulating self-renewal and differentiation of human bone marrow derived mesenchymal stromal cells (hBMSCs) remains unknown. Herein, we report that USP7 regulates self-renewal of hBMSCs and is required during the early stages of osteogenic, adipogenic, and chondrogenic differentiation of hBMSCs. USP7, a deubiquitinating enzyme (DUB), was found to be downregulated during hBMSC differentiation. Furthermore, USP7 is an upstream regulator of the self-renewal regulating proteins SOX2 and NANOG in hBMSCs. Moreover, we observed that SOX2 and NANOG are poly-ubiquitinated and their expression is downregulated in USP7-deficient hBMSCs. Overall, this study showed that USP7 is required for maintaining self-renewal and multipotency in cultured hBMSCs. Targeting USP7 might be a novel strategy to preserve the self-renewal capacity of hBMSCs intended for stem cell therapy.

Sodium Tetradecyl Sulphate Sclerotherapy for Lateral Malleolar Bursitis of the Ankle.

Background: The aim of this study was to evaluate clinical outcomes of sodium tetradecyl sulphate (STS) sclerotherapy for conservative treatment of lateral malleolar bursitis of the ankle. Methods: We reviewed data from 20 consecutive patients (20 ankles) who underwent STS sclerotherapy between August 2018 and June 2019. After aspiration of fluid from the lateral malleolar bursal sac, 2 mL (20 mg) STS was injected into the sac. Clinical outcomes and side effects and complications were evaluated at 2 weeks, 3 months, 1 year, and 2 years after sclerotherapy. Responses to treatment were assessed according to degree of fluctuation, shrinkage of the bursal sac, and soft-tissue swelling. The 36-item short form survey (SF-36) was completed for each patient before and after therapy. Results: Complete response was observed in 17 patients (85%), and partial response was observed in 3 patients (15%) after STS sclerotherapy. SF-36 physical component scores improved from 62.2 (interquartile range, 5.2) before therapy to 70.0 (interquartile range, 7.9) at last follow-up (p < 0.05). One patient (5%) experienced transient hyperpigmentation at the injection site. No major complications occurred. Conclusions: STS sclerotherapy was an effective and safe treatment for patients with lateral malleolar bursitis of the ankle.

Long-Term Clinical Outcomes and Implant Survivorship of 151 Total Ankle Arthroplasties Using the HINTEGRA Prosthesis: A Minimum 10-Year Follow-up.

BACKGROUND: Few studies have investigated long-term clinical outcomes of a mobile-bearing total ankle arthroplasty (TAA) system. This study analyzed long-term outcomes of TAA using the HINTEGRA prosthesis at a single, non-developer center. METHODS: Primary TAAs were performed on 213 ankles in 194 patients, and 151 consecutive ankles [71%] in 136 patients with a minimum follow-up of 10 years after the primary TAA were included in this study. Clinical results were assessed using a visual analog scale (VAS) pain score, the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Scale score, the Ankle Osteoarthritis Scale (AOS) pain and disability subscores, and ankle range of motion. Prosthesis survivorship, reoperations, and risk factors were also evaluated. RESULTS: The mean follow-up was 135.5 months (range, 120.0 to 204.0 months). All clinical scores and ankle range of motion improved significantly from preoperatively to 2 years, 4 to 6 years, and ≥10 years after TAA (p < 0.001). A total of 43 ankles (28.5%) required revision procedures, with the most common reason being periprosthetic osteolysis (32 ankles [21.2%]). The overall implant survivorship was 93.5% in Kaplan-Meier survival analysis at the mean follow-up of 11.3 years after the TAA. CONCLUSIONS: TAA using the HINTEGRA prosthesis with careful follow-up observation and appropriate adjunct procedures for the treatment of end-stage ankle arthritis produced satisfactory clinical results, which were maintained at a follow-up of ≥10 years, and resulted in 93.5% of implant survivorship. LEVEL OF EVIDENCE: Prognostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Drug repositioning of polaprezinc for bone fracture healing.

Fractures and related complications are a common challenge in the field of skeletal tissue engineering. Vitamin D and calcium are the only broadly available medications for fracture healing, while zinc has been recognized as a nutritional supplement for healthy bones. Here, we aimed to use polaprezinc, an anti-ulcer drug and a chelate form of zinc and L-carnosine, as a supplement for fracture healing. Polaprezinc induced upregulation of osteogenesis-related genes and enhanced the osteogenic potential of human bone marrow-derived mesenchymal stem cells and osteoclast differentiation potential of mouse bone marrow-derived monocytes. In mouse experimental models with bone fractures, oral administration of polaprezinc accelerated fracture healing and maintained a high number of both osteoblasts and osteoclasts in the fracture areas. Collectively, polaprezinc promotes the fracture healing process efficiently by enhancing the activity of both osteoblasts and osteoclasts. Therefore, we suggest that drug repositioning of polaprezinc would be helpful for patients with fractures.

Association between outdoor temperature and achilles tendon repair: A 14-years nationwide population-based cohort study.

The incidence of achilles tendon rupture varies by gender, age, and seasonal variation. However, there has been no study as yet linking achilles tendon rupture to daily fluctuations in outdoor temperature. The purpose of this study was to investigate the association between outdoor temperature and achilles tendon rupture using a Korea Meteorological Administration database and a Korean National Health Insurance Service-National Sample Cohort database. Between 2002 and 2015, all instances of achilles tendon repair were retrieved from the National Health Insurance Service-National Sample Cohort database to examine sociodemographic factors, specifically sex, age, residential area, and income level. Minimum age requirement was 20 years. Outdoor temperatures recorded at 16 observation points in South Korea were also acquired from the Korea Meteorological Administration data center for analysis. Overall, 850 (0.119%) of 713,456 individuals in the National Health Insurance Service-National Sample Cohort database underwent achilles tendon repair between 2002 and 2015. Yearly procedural totals increased with advancing age, peaking at ages 30-39 years (14.6 per 100,000 persons) and declining thereafter. Minimum, median, and maximum outdoor temperatures were associated with achilles tendon repair (p<0.05), as did household income. In multivariate logistic regression analysis, outdoor temperatures, sex, age, and household income emerged as factors significantly associated with achilles tendon repair. Outcomes of this study confirm an association between incidence of achilles tendon repair and outdoor temperature, the latter denoting a novel index and likely surrogate measure of vigorous physical activity afforded by warmer weather.

TLR4 downregulation by the RNA-binding protein PUM1 alleviates cellular aging and osteoarthritis.

Dysfunction of mRNA or RNA-binding proteins (RBPs) causes cellular aging and age-related degenerative diseases; however, information regarding the mechanism through which RBP-mediated posttranscriptional regulation affects cellular aging and related disease processes is limited. In this study, PUM1 was found to be associated with the self-renewal capacity and aging process of human mesenchymal stem cells (MSC). PUM1 interacted with the 3'-untranslated region of Toll-like receptor 4 (TLR4) to suppress TLR4 mRNA translation and regulate the activity of nuclear factor-κB (NF-κB), a master regulator of the aging process in MSCs. PUM1 overexpression protected MSCs against H2O2-induced cellular senescence by suppressing TLR4-mediated NF-κB activity. TLR4-mediated NF-κB activation is a key regulator in osteoarthritis (OA) pathogenesis. PUM1 overexpression enhanced the chondrogenic potential of MSCs even under the influence of inflammation-inducing factors, such as lipopolysaccharide (LPS) or interleukin-1ß (IL-1ß), whereas the chondrogenic potential was reduced following the PUM1 knockdown-mediated TLR4 activation. PUM1 levels decreased under inflammatory conditions in vitro and during OA progression in human and mouse disease models. PUM1 knockdown in human chondrocytes promoted chondrogenic phenotype loss, whereas PUM1 overexpression protected the cells from inflammation-mediated disruption of the chondrogenic phenotype. Gene therapy using a lentiviral vector encoding mouse PUM1 showed promise in preserving articular cartilage integrity in OA mouse models. In conclusion, PUM1 is a novel suppressor of MSC aging, and the PUM1-TLR4 regulatory axis represents a potential therapeutic target for OA.

Outcomes of oblique supramalleolar osteotomy without fibular osteotomy for congruent- and incongruent-type medial ankle arthritis.

BACKGROUND: Although high talar tilt and ankle mortise incongruence are risk factors for supramalleolar osteotomy (SMO), no study on lateral talofibular joint congruence exists. We aimed to evaluate the outcomes of oblique SMO without fibular osteotomy for medial ankle arthritis and compare them according to the lateral talofibular joint congruity. METHODS: Forty-eight ankles were retrospectively reviewed and divided according to preoperative talofibular joint congruity (congruent, 22 [45.8%] vs. incongruent, 26 [54.2%]). RESULTS: The mean VAS score, AOFAS score, and modified Takakura stage were significantly improved. No significant differences were noted in clinical outcomes, but the mean postoperative tibiotalar angle and difference between the upper and lower talofibular gaps were significantly different in both groups (p = 0.004 and p = 0.009, respectively). The mean Takakura stage at 1 and 2 years after surgery was higher in the incongruent group (p = 0.013, p = 0.012). CONCLUSION: This procedure was effective against early- to mid-stage medial ankle arthritis. Radiographic arthritic grade changed according to the talofibular joint congruity.

Cellular and Tissue Selectivity of AAV Serotypes for Gene Delivery to Chondrocytes and Cartilage.

Background: Despite several studies on the effect of adeno-associated virus (AAV)-based therapeutics on osteoarthritis (OA), information on the transduction efficiency and applicable profiles of different AAV serotypes to chondrocytes in hard cartilage tissue is still limited. Moreover, the recent discovery of additional AAV serotypes makes it necessary to screen for more suitable AAV serotypes for specific tissues. Here, we compared the transduction efficiencies of 14 conventional AAV serotypes in human chondrocytes, mouse OA models, and human cartilage explants obtained from OA patients. Methods: To compare the transduction efficiency of individual AAV serotypes, green fluorescent protein (GFP) expression was detected by fluorescence microscopy or western blotting. Likewise, to compare the transduction efficiencies of individual AAV serotypes in cartilage tissues, GFP expression was determined using fluorescence microscopy or immunohistochemistry, and GFP-positive cells were counted. Results: Only AAV2, 5, 6, and 6.2 exhibited substantial transduction efficiencies in both normal and OA chondrocytes. All AAV serotypes except AAV6 and rh43 could effectively transduce human bone marrow mesenchymal stem cells. In human and mouse OA cartilage tissues, AAV2, AAV5, AAV6.2, AAV8, and AAV rh39 showed excellent tissue specificity based on transduction efficiency. These results indicate the differences in transduction efficiencies of AAV serotypes between cellular and tissue models. Conclusions: Our findings indicate that AAV2 and AAV6.2 may be the best choices for AAV-mediated gene delivery into intra-articular cartilage tissue. These AAV vectors hold the potential to be of use in clinical applications to prevent OA progression if appropriate therapeutic genes are inserted into the vector.

Downregulation of MicroRNA-495 Alleviates IL-1ß Responses among Chondrocytes by Preventing SOX9 Reduction.

PURPOSE: Our previous work demonstrated that miRNA-495 targets SOX9 to inhibit chondrogenesis of mesenchymal stem cells. In this study, we aimed to investigate whether miRNA-495-mediated SOX9 regulation could be a novel therapeutic target for osteoarthritis (OA) using an in vitro cell culture model. MATERIALS AND METHODS: An in vitro model mimicking the OA environment was established using TC28a2 normal human chondrocyte cells. Interleukin-1ß (IL-1ß, 10 ng/mL) was utilized to induce inflammation-related changes in TC28a2 cells. Safranin O staining and glycosaminoglycan assay were used to detect changes in proteoglycans among TC28a2 cells. Expression levels of COX-2, ADAMTS5, MMP13, SOX9, CCL4, and COL2A1 were examined by qRT-PCR and/or Western blotting. Immunohistochemistry was performed to detect SOX9 and CCL4 proteins in human cartilage tissues obtained from patients with OA. RESULTS: miRNA-495 was upregulated in IL-1ß-treated TC28a2 cells and chondrocytes from damaged cartilage tissues of patients with OA. Anti-miR-495 abolished the effect of IL-1ß in TC28a2 cells and rescued the protein levels of SOX9 and COL2A1, which were reduced by IL-1ß. SOX9 was downregulated in the damaged cartilage tissues of patients with OA, and knockdown of SOX9 abolished the effect of anti-miR-495 on IL-1ß-treated TC28a2 cells. CONCLUSION: We demonstrated that inhibition of miRNA-495 alleviates IL-1ß-induced inflammatory responses in chondrocytes by rescuing SOX9 expression. Accordingly, miRNA-495 could be a potential novel target for OA therapy, and the application of anti-miR-495 to chondrocytes could be a therapeutic strategy for treating OA.