BACKGROUND:Osteoarthritis (OA) is characterized by progressive degeneration of articular cartilage, and current treatments often result in suboptimal fibrous cartilage repair. This study explored the effects of polydopamine-coated gold nanoparticles (PD-AuNPs) on cartilage repair and OA-related changes. METHODS:PD-AuNPs were synthesized using dopamine hydrochloride as a surface coating for AuNPs and characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy. Their effects were evaluated in vitro using adipose-derived mesenchymal stem cells and in vivo using a cartilage defect rat model and a monosodium iodoacetate-induced OA model. In the defect model, a biocompatible hydrogel composed of polydimethylsiloxane and sodium hyaluronate was used as a carrier. SIGNIFICANT FINDINGS:In vitro, PD-AuNPs was associated with upregulated expression of the chondrogenic markers aggrecan (ACAN) (∼ 1.6-fold) and SRY-box transcription factor 9 (SOX9) (∼ 1.2-fold) compared with AuNPs alone. In vivo, PD-AuNPs improved repair outcomes in the defect model, showing higher scores for defect filling (3.7 vs. 2.3), osteochondral reconstitution (1.7 vs. 0.6), cell morphology (2.3 vs. 1.2), and matrix staining (3.3 vs. 1.3), along with enhanced ACAN and SOX9 expression. In the OA model, PD-AuNP was associated with reduced OA-related changes, including improved weight-bearing (49.5 % vs. 47.0 %), reduced joint swelling, and a markedly lower final OARSI score (2.7 vs. 12.8). They also increased ACAN and SOX9 while decreasing IL-6 and MMP-9 compared with AuNPs. Collectively, these results suggest that PD-AuNPs contribute to cartilage preservation and repair, offering a potential approach for improving cartilage regeneration strategies.

Proteolysis-targeting chimeras (PROTACs) degrade target proteins through the ubiquitin-proteasome system. To date, PROTACs are primarily used to treat various diseases; however, they have not been applied in regenerative therapy. Herein, this work introduces MDM2-targeting PROTACs customized for application in bone regeneration. An MDM2-PROTAC library is constructed by combining Nutlin-3 and CRBN ligands with various linker designs. Through a multistep validation process, this work develops MDM2-PROTACs (CL144 and CL174) that presented potent degradation efficiency and a robust inductive effect on the biomineralization. Next, this work performs whole-transcriptome analysis to dissect the biological effects of the CL144, and reveals the upregulation of osteogenic marker genes. Furthermore, CL144 effectively induced bone regeneration in bone graft and ovariectomy (OVX) models after local and systemic administration, respectively. In the OVX model, the combination treatment with CL144 and alendronate induced a synergistic effect. Overall, this study demonstrates the promising role of MDM2-PROTAC in promoting bone regeneration, marking the first step toward expanding the application of the PROTAC technology.

Osteoarthritis (OA) affects millions globally, with its prevalence expected to rise due to an aging population. Selenium nanoparticles (SeNPs) have shown therapeutic potential, and polydopamine (PDA) coatings on nanoparticles offered additional benefits, including enhanced biocompatibility, antioxidant properties, and anti-inflammatory effects. However, while SeNPs and PDA have demonstrated efficacy in several disease models, their role in OA remains underexplored. This study aimed to evaluate the therapeutic effects of PDA-coated SeNPs in the treatment of OA. We developed PDA-coated SeNPs (PDA-SeNP) to improve Reactive Oxygen Species (ROS) control and evaluated their anti-inflammatory and cartilage-regenerative effects in both in vitro and in vivo models of OA. Transmission electron microscopy confirmed that the sizes of PDA-SeNPs was 203 ± 11 nm, with PDA coatings of approximately 12 ± 2 nm on the SeNPs. In vitro, treatment with PDA-SeNPs significantly enhanced the expression of cartilage-regeneration markers while reducing inflammatory marker levels in chondrocytes. For the in vivo analysis, OA was induced by injecting monoiodoacetate into the knee joints of rats. Four weeks after treatment with phosphate-buffered saline (PBS, n = 6), SeNPs (n = 6), or PDA-SeNPs (n = 6), the incapacitance test demonstrated improved weight-bearing capacity in the SeNP and PDA-SeNP groups compared to the PBS control. Gross morphological assessment and histological analysis revealed that PDA-SeNPs mitigated cartilage damage more effectively than SeNPs alone. These findings suggest that PDA-SeNPs promote cartilage repair, enhance extracellular matrix synthesis, and reduce knee pain in OA, establishing them as promising candidates for future OA treatment.

Bifunctional trans-cyclooctene (bTCO) with a carbamate or carbonate at the allylic position and tetrazine provide a promising bioorthogonal click chemistry pair for the click-to-release approach, successfully employed in various biotechnological applications. Herein, we demonstrate a simple and straightforward method to synthesize C2TCO, a symmetrical bTCO derivative with two hydroxyl groups at the allylic positions. The efficiently synthesized C2TCO at first was selectively functionalized with a fluorophore (C2TCO-FL), and the conjugate was labeled onto monoclonal antibodies (Ab-C2TCO-FL). The fluorophore of Ab-C2TCO-FL was easily removed from the antibody through the mild treatment of tetrazine, enabling multicycle fluorescent bioimaging. Next, an antibody-drug conjugate targeting PD-L1 was prepared using the linker based on C2TCO. The cytotoxic payload was efficiently released from the antibody upon tetrazine treatment, which induced cellular cytotoxicity.

Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) was recently identified as a major hydrolase of an endogenous stimulator of interferon genes (STING) agonist, 2 ',3 '-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP). ENPP1 is a promising therapeutic target in cancer immunotherapy, in which the inhibition of ENPP1 enhances anticancer immunity via STING-mediated innate immune activation. This review highlights the role of ENPP1 in innate immunity and the recent discovery of small molecule ENPP1 inhibitors as immunomodulators in cancer immunotherapy.

A lack of the T cell-inflamed tumor microenvironment limits the efficacy of immune checkpoint inhibitors (ICIs). Activation of stimulator of interferon genes (STING)-mediated innate immunity has emerged as a novel therapeutic approach in cancer therapy. 2',3'-Cyclic GMP-AMP (cGAMP) is a natural STING agonist; however, cGAMP is subjected to endogenous degradation by ecto-nucleotide pyrophosphatase phosphodiesterase 1 (ENPP1). To improve the ICI response rate, we developed 29f, a novel ENPP1 inhibitor with phthalazin-1(2H)-one as the core scaffold. 29f inhibited the cGAMP hydrolysis by ENPP1 in vitro (IC50 = 68 nM) and enhanced the STING-mediated type I interferon response in both immune and tumor cells. 29f demonstrated excellent metabolic stability and bioavailability (F = 65%). Orally administered 29f promoted tumor growth inhibition in a CT26 syngeneic model and increased the anti-PD-L1 response. Furthermore, 29f-induced immunological memory prevented the tumor relapse against tumor rechallenge, suggesting the promising therapeutic potential of 29f.

Fluorescent molecules have been used for various applications in biological system monitoring. Considering the complexity of cellular systems, there is a huge demand for diverse fluorescent organic molecular scaffolds. However, only a limited number of fluorescent scaffolds have been reported due to the lack of a rational design strategy. We serendipitously discovered N4-phenylquinazoline-4,6-diamine as a fluorescent scaffold with turn-on characteristics. To improve the photophysical property of the initial fluorescence molecule, we synthesized derivatives of the N4-phenylquinazoline-4,6-diamine and found systematic correlation between electronic density of the phenyl substituent of the scaffold and fluorescence intensity. Through tuning the photophysical property of the scaffold and a rational design strategy, we developed N4-dichlorophenylquinazoline-4,6-diamine as a potential fluorophore for various biological applications. To prove the value of the developed fluorescent scaffold, we devised formaldehyde (FA) fluorescent sensor by tailoring amine on 6-position of N4-dichlorophenylquinazoline-4,6-diamine to employ a 2-aza-Cope rearrangement as the molecular detection mechanism with double-digit nanomolar detection limits. FA level in live HeLa cells were successfully visualized with the probe, exhibiting that N4-dichlorophenylquinazoline-4,6-diamine can serve as a useful molecular scaffold for offering various fluorescent sensors toward the investigation of physiological and pathological processes in live cells.

For fluorogenic bioimaging of the endoplasmic reticulum, a new aggregation-induced emission luminogen (AIEgen) core skeleton was conjugated with glibenclamide. Click chemistry was successfully employed for the efficient conjugation between azide-modified glibenclamide and alkyne-containing indolizine core skeleton to generate Aru68. When the volume fraction of water is increases in the solution of Aru68 in water and DMF induced aggregates formation and simultaneous increase of fluorescence intensity up to 100-fold was observed. Solvatochromism and restriction of molecular motion study by perturbation of solvent polarity index and volume fraction of glycerin in glycerin/methanol mixture provided a mechanistic insight into the turn-on phenomenon of Aru68 as AIEgen. The final bio-imaging demonstration of Aru68 in live cell conditions revealed great potential not only of the probe for wash-free bioimaging of the endoplasmic reticulum but also of the indolizine core skeleton for efficient fluorogenic bioprobe development based on aggregation-induced emission processes.

Background and Objectives: Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used to control pain and fever. However, their effect on COVID-19 infected patients has not been fully studied. In this study, we investigated the effect of the duration of NSAIDs use on COVID-19 infection and clinical outcomes. Materials and Methods: In South Korea, 25,739 eligible patients who received COVID-19 testing between 1 January and 31 July 2020, were included in this retrospective observational cohort analysis. Based on the date of the first COVID-19 test for each patient, NSAID prescription dates were used to separate patients into two groups (short-term group: <2 weeks; long-term group: 8–12 weeks). COVID-19 infectivity and clinical outcomes were analyzed. We used the propensity score-matching (PSM) method. Results: Of the 580 patients who had taken NSAIDs before the date of COVID-19 test, 534 and 46 patients were grouped in the short- and long-term NSAID-use groups, respectively. We did not find a statistically significant increased risk of COVID-19 infection (adjustment for age and sex, p = 0.413; adjustment for age, sex, region of residence, comorbidity, Charlson Comorbidity Index, and current use of medication, p = 0.259) or change in clinical outcomes, including conventional oxygen therapy, admission of intensive care unit, artificial ventilation, or death, between the two groups in which the PSM method was applied. Conclusions: The duration of NSAIDs use did not have a statistically significant effect on COVID-19 infectivity or clinical outcomes. However, further studies looking at clinical presentation and laboratory test results in a large number of people should be performed.

BACKGROUND AND AIMS:Cardiovascular diseases (CVD), including coronary heart disease, are the leading cause of death worldwide. Several studies investigating the relationship between fish intake, methylmercury exposure, and CVDs in adults have reported inconsistent results. This study aimed to determine the association between hair methylmercury levels and arterial stiffness using brachial-ankle pulse wave velocity (baPWV). METHODS:This cross-sectional study included 891 seemingly healthy Korean adults (418 men and 473 women). The anthropometric and biochemical profiles, including methylmercury levels in the hair, were measured. Arterial stiffness was measured using baPWV, wherein high baPWV was defined as >1375 cm/s (>75th percentile). The odds ratios for high baPWVs were examined using multivariable logistic regression analysis after adjusting for potential confounders across the quintiles of hair methylmercury levels (Q1 = ≤0.6, Q2 = 0.6-0.8, Q3 = 0.8-1.1, Q4 = 1.1-1.5, and Q5=>1.5 μg/g). RESULTS:After adjusting for multiple confounders-age, sex, height, body weight, smoking status, weekly alcohol consumption, total metabolic equivalent of task, mean arterial blood pressure, resting heart rate, triglycerides, low density lipoprotein cholesterol, fasting plasma glucose, uric acid and white blood cell count-the odds ratios (95% confidence intervals) for high baPWVs in each quintile of hair methylmercury levels were 1.00, 0.36 (0.17-0.76), 0.38 (0.20-0.76), 0.28 (0.13-0.61), and 0.49 (0.24-0.99), respectively. CONCLUSIONS:Within non-toxic low levels, higher hair methylmercury levels are independently associated with lower arterial stiffness in seemingly healthy Korean adults regardless of classical cardiovascular risk factors.

An efficient and transition-metal-free three-component reaction with benzynes formed in situ from 2-(trimethylsilyl)aryl triflate, phosphites, and ketones was developed for the synthesis of benzoxaphosphole 1-oxides. An array of benzoxaphosphole 1-oxides were prepared from both activated and non-activated ketones in moderate to good yields with a broad functional group tolerance. This reaction is useful for preparing organophosphorus compounds encountered in natural products and materials.

MicroRNAs are key regulators of gene expression in tumorigenesis. In this study, we investigated the tumor-suppressive function of miR-31-3p. Analysis of the Gene Expression Omnibus database revealed that the expression of miR-31-3p in prostate cancer tissues is lower than that in adjacent normal tissues from patients with prostate cancer. Moreover, miR-31-3p induces apoptosis in DU145, PC-3, and LNCap prostate cancer cells, while those transfected with miR-31-3p exhibit significantly decreased cell proliferation, migration, invasiveness, and tumor sphere-forming ability, as determined using the cell counting kit-8, transwell, and sphere-forming assays. Further analysis revealed that GABBR2 is a direct target of miR-31-3p. Within a DU145 xenograft murine model, intratumoral injection of a miR-31-3p mimic suppresses tumor growth. Taken together, the findings of this study suggest that miR-31-3p performs a novel tumor-suppressive function in prostate cancer and may represent a novel target for anti-prostate cancer miRNA therapeutics.

Background: The substance P–neurokinin 1 receptor pathway has been proposed as a therapeutic target for tendinopathy. However, there is a lack of evidence regarding its practical applications. Purpose: To investigate the therapeutic effects of substance P inhibitor (SPI) on inflamed tenocytes in vitro and in a collagenase-induced rat model of tendinopathy in vivo. Study Design: Controlled laboratory study. Methods: We analyzed the mRNA levels of inflammatory (cyclooxygenase [COX]-2 and interleukin [IL]-6) and tenogenic (Mohawk and scleraxis [SCX]) markers using reverse transcription quantitative polymerase chain reaction to demonstrate the effects of SPI on lipopolysaccharide-treated (inflamed) tenocytes. A collagenase-induced rat model of tendinopathy was created by injecting 20 µL of collagenase into the Achilles tendon. A behavior test using an incapacitance apparatus was performed to detect changes in postural equilibrium. The tendon specimens were obtained, and their gross findings were examined. The tensile strength was measured, and histopathological evaluation was performed (hematoxylin and eosin, alcian blue, and immunohistochemical staining). Results: The mRNA levels of COX-2, IL-6, Mohawk, and SCX differed significantly between inflamed tenocytes and those treated with SPI. SPI improved the weight burden in a rat model of tendinopathy in a behavioral test. The specimens of the SPI group showed a normal tendon-like appearance. In the biomechanical test, the tensile strength of the SPI group was significantly greater than that of the tendinopathy group. In the histopathological evaluation, the degree of collagen matrix breakdown was mild in the SPI group. In alcian blue staining, only small focal depositions of proteoglycans and glycosaminoglycans were observed in the SPI group. The SPI group showed decreased expression of IL-6 and neurokinin 1 receptor. Conclusion: This study suggests that SPI has therapeutic effects on tendon healing and restoration in a collagenase-induced rat model of tendinopathy. Clinical Relevance: SPI is a promising agent for tendinopathy in humans.

Background This study aimed to discover the most stable outcome among different Kirschner-wire (K-wire) configurations for fixation of a lateral condyle fracture (Milch type II) in different loads of stress by using finite element analyses (FEA). Methods The right humerus of a 6-year-old boy with a lateral condyle fracture (Milch type II), was modelled with a computer aided engineering. Using FEA, peak von Mises stress and stiffness were evaluated first for a single K-wire fixation by varying the angle (0, 5, 10, 15, 20, 25, 30 degrees). Then, based on the single K-wire result, assessment of peak von Mises stress and stiffness were evaluated via FEA for two- or three-wire fixation under various configurations (two convergent, two parallel, three divergent). Results Single K-wire fixation by 5 and 25 degrees had the lowest peak von Mises stress. The fracture site showed higher stiffness at 0, 5 and 15 degrees. Considering the collected results and clinical situation, 5 degree K-wire was selected for the FEA of multiple K-wire fixation. For multiple K-wire fixation, three divergent (5-20-35 degrees) K-wires showed better stability, both in peak von Mises stress and stiffness, than any two-K-wire configurations. Among two K-wire fixations, two divergent (5-50 degrees) K-wires provided the lowest von Mises stress in varus and valgus while two divergent (5-65 degrees) K-wires showed better results in flexion, extension, internal and external rotation, and both configurations showed similar results in stiffness. Conclusions We successfully created a paediatric lateral condyle fracture (Milch type II) model which was used to conduct FEA on different K-wire configurations to achieve stability of the fracture. Our results show that an initial K-wire inserted at 5 degrees, followed by the insertion of a second divergent wire at either 45 or 60 degrees provides the most stability in two K-wire fixations in this type of fracture repair.

Objectives: Sarcopenia is a skeletal muscle loss disease with adverse outcomes, including falls, mortality, and cardiovascular disease (CVD) in older patients. Distal radius fractures (DRF), common in older people, are strongly related to falls. We aimed to investigate the correlation between DRF and low skeletal muscle mass, which strongly correlated to sarcopenia. Methods: We performed a retrospective review of data from patients diagnosed with or without DRF in our institute between 2015 and 2020. Finally, after propensity score matching, data from 115 patients with and 115 patients without DRF were used for analyses. Multivariate logistic regression analysis was performed for sex, body mass index (BMI), the presence of low skeletal muscle mass, bone quality measured by dual-energy X-ray absorptiometry (DXA), and comorbidities (diabetes mellitus, CVD). Results: We found that female sex (odds ratio = 3.435, p = 0.015), CVD (odds ratio = 5.431, p < 0.001) and low skeletal muscle mass (odds ratio = 8.062, p = 0.001) were significant predictors for DRF. BMI and osteoporosis were not statistically significantly related to DRF. Conclusions: Women with low skeletal muscle mass and CVD may be more responsible for DRF than osteoporosis.

A rotator cuff is a muscle and tendon surrounding the shoulder joint, and a rotator cuff tear can be caused by overuse or injury, which leads to great pain in affected individuals. However, rotator cuff tear is a multifactorial process whose underlying mechanism is still unclear. Many previous studies have suggested an important role of genetic predisposition, such as single-nucleotide polymorphisms (SNPs), in explaining the genesis of tendinopathy. This study aimed to identify specific genes or genetic variants associated with rotator cuff tears by performing a genome-wide association study (GWAS) using an independent case of rotator cuff tears. GWAS was performed using data from CHA Bundang Medical Center with 20 cases of rotator cuff tears, and 20 cases of healthy controls genotyped on the Illumina HiSeq 2500. Tests of association were performed using the Burrows–Wheeler Aligner (BWA) software at 284,246 SNPs. Data were filtered based on sequence ontology, minor allele frequency, and Hardy–Weinberg equilibrium values, and SNPs were considered significant if the p-value was <0.05. The tests of association revealed more than 20 significantly associated SNPs. SNPs showing the highest significance occurred in candidate genes, including LAIR2 (rs2287828, OR 9.116, p-value 5.49 × 10−4) on chromosome 19 and CRIPAK (rs9328733, OR 6, p-value 1.11 × 10−3) and REST (rs2228991, OR 8.222, p-value 1.20 × 10−3) on chromosome 4. This study attempted to identify genetic variants influencing rotator cuff tears through a genome-wide association study using a dense set of SNPs. More than 20 SNPs were significantly associated with rotator cuff tears. The major limitation of this study is that it was conducted on a small study group and requires further validation. Nevertheless, the identification of potential genetic variants related to rotator cuff injury would aid in the early detection of individuals at risk for the development of tendinopathy and will provide insight into future gene therapies.

Background Colchicine is a traditional medication that is currently approved to treat gout and familial Mediterranean fever (FMF). However, colchicine has a wide range of anti-inflammatory activities, and several studies have indicated that it may be useful in a variety of other conditions, such as rheumatic disease, cardiac disease, and cancer. Osteosarcoma, the most common type of bone sarcoma, is derived from primitive bone-forming mesenchymal cells. In this study, we investigated whether colchicine could be used to treat osteosarcoma through the regulation of cell cycle signaling. Methods Two human osteosarcoma cell lines, U2OS and Saos-2, were used. A clonogenic assay was used to determine the antiproliferative effects of colchicine on osteosarcoma cells. Reactive oxygen species (ROS) production and apoptosis were measured by flow cytometry. Migration and invasion assays were performed to investigate the inhibitory effects of colchicine. The signaling pathways related to colchicine treatment were verified by GO biological process (GOBP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Results Colchicine was selected as the lead compound based on the results of initial screening and cell viability assays conducted in Saos-2 and U2Os cells. Colchicine reduced the viability of Saos-2 and U2OS cells in a concentration-dependent manner. It also significantly inhibited colony-forming ability and induced ROS production and apoptosis. It also inhibited the migration and invasion of both Saos-2 and U2OS cells. GOBP and KEGG enrichment analyses indicated the involvement of microtubule-based processes and cancer-related pathways. Conclusions These findings suggest that colchicine has therapeutic potential in osteosarcoma.

Mucin-type O-glycosylation is among the most complex post-translational modifications. Despite mediating many physiological processes, O-glycosylation remains understudied compared to other modifications, simply because the right analytical tools are lacking. In particular, analysis of intact O-glycopeptides by mass spectrometry is challenging for several reasons; O-glycosylation lacks a consensus motif, glycopeptides have low charge density which impairs ETD fragmentation, and the glycan structures modifying the peptides are unpredictable. Recently, we introduced chemically modified monosaccharide analogues that allowed selective tracking and characterization of mucin-type O-glycans after bioorthogonal derivatization with biotin-based enrichment handles. In doing so, we realized that the chemical modifications used in these studies have additional benefits that allow for improved analysis by tandem mass spectrometry. In this work, we built on this discovery by generating a series of new GalNAc analogue glycopeptides. We characterized the mass spectrometric signatures of these modified glycopeptides and their signature residues left by bioorthogonal reporter reagents. Our data indicate that chemical methods for glycopeptide profiling offer opportunities to optimize attributes such as increased charge state, higher charge density, and predictable fragmentation behavior.

There is growing research interest from many scientific, healthcare, and industrial applications toward the development of high-precision optical pH sensors that cover a broad pH range. Despite enthusiastic endeavors, however, it remains challenging to develop cost-effective, high-precision, and broadband working paper-striptype optical pH measurement systems, particularly for on-site or in-the-field pH sensing applications. We develop a fluorescent array based on a KIz system for accurate pH level classification. Based on the indolizine fluorescent core skeleton, a library of 30 different pH-responsive fluorescent probes is rationally designed and efficiently synthesized. Spotting the compounds in a checkered pattern (5 x 6) allows for the development of a disposable compound array on wax-printed cellulose paper. Compounds sharing a single chemical core skeleton result in the interrogation of all the components of a system with a single excitation light, resulting in a simple system design for pH classification. Furthermore, we design a 3D-printed enclosure to capture the fluorescence pattern changes of the array by using an intelligent, smartphone-based, handheld pH detection system. Specifically, by exploiting a random forest-based machine learning algorithm on a smartphone, we can effectively analyze the fluorescence pattern changes. Our results suggest that our proposed system can classify pH levels in fine-grain (0.2 pH) units.