Biomechanical Study of Porcine Osteoporotic Vertebral Compression Fracture Model Strengthened by Trajectory-Adjustable Bone Cement Filling Device.

OBJECTIVE: To establish a porcine osteoporotic vertebral compression fracture model and compare the impact of unilateral vertebroplasty using trajectory-adjustable bone cement filling device to traditional surgical tools on vertebral biomechanics. METHODS: Twenty-four fresh adult porcine vertebrae were used to establish an osteoporotic vertebral compression fracture model. The specimens were divided into 4 groups (A, B, C, and D), each consisting of 6 vertebrae. Group A served as the control group without vertebral augmentation (percutaneous vertebroplasty [PVP]). Patients in Group B underwent unilateral PVP using conventional surgical tools, while patients in Group C underwent bilateral PVP using the same tools. In Group D, patients underwent unilateral PVP with a trajectory-adjustable bone cement filling device. Postoperative X-ray examinations were performed to assess cement distribution and leakage. The compressive stiffness and strength of each spinal unit were evaluated using an electronic mechanical testing machine. RESULTS: In Groups B, C, and D, the percentages of total cement distribution area were 32.83 ± 3.64%, 45.73 ± 2.27%, and 47.43 ± 3.51%, respectively. The values were significantly greater in Groups C and D than in Group B (P < 0.05), but there was no significant difference between Groups C and D (P > 0.05). The stiffness after vertebral augmentation in Groups B, C, and D was 1.04 ± 0.23 kN/mm, 1.11 ± 0.16 KN/mm, and 1.15 ± 0.13 KN/mm, respectively, which were significantly greater than that in Group A (0.46 ± 0.06 kN/mm; P < 0.05). The ultimate compressive strengths in Groups B, C, and D were 2.53 ± 0.21 MPa, 4.09 ± 0.30 MPa, and 3.99 ± 0.29 MPa, respectively, all surpassing Group A's strength of 1.41 ± 0.31 MPa. Additionally, both Groups C and D demonstrated significantly greater ultimate compressive strengths than Group B did (P < 0.05). CONCLUSIONS: A trajectory-adjustable bone cement filling device was proven to be an effective approach for unilateral vertebroplasty, restoring the biomechanical properties of fractured vertebrae. Compared to traditional surgical tools, this approach is superior to unilateral puncture and yields outcomes comparable to those of bilateral puncture. Additionally, the device ensures a centrally symmetrical distribution pattern of bone cement, leading to improved morphology.

A real-time deep learning-based system for colorectal polyp size estimation by white-light endoscopy: development and multicenter prospective validation.

BACKGROUND: The choice of polypectomy device and surveillance intervals for colorectal polyps are primarily decided by polyp size. We developed a deep learning-based system (ENDOANGEL-CPS) to estimate colorectal polyp size in real time. METHODS: ENDOANGEL-CPS calculates polyp size by estimating the distance from the endoscope lens to the polyp using the parameters of the lens. The depth estimator network was developed on 7297 images from five virtually produced colon videos and tested on 730 images from seven virtual colon videos. The performance of the system was first evaluated in nine videos of a simulated colon with polyps attached, then tested in 157 real-world prospective videos from three hospitals, with the outcomes compared with that of nine endoscopists over 69 videos. Inappropriate surveillance recommendations caused by incorrect estimation of polyp size were also analyzed. RESULTS: The relative error of depth estimation was 11.3% (SD 6.0%) in successive virtual colon images. The concordance correlation coefficients (CCCs) between system estimation and ground truth were 0.89 and 0.93 in images of a simulated colon and multicenter videos of 157 polyps. The mean CCC of ENDOANGEL-CPS surpassed all endoscopists (0.89 vs. 0.41 [SD 0.29]; P<0.001). The relative accuracy of ENDOANGEL-CPS was significantly higher than that of endoscopists (89.9% vs. 54.7%; P<0.001). Regarding inappropriate surveillance recommendations, the system's error rate is also lower than that of endoscopists (1.5% vs. 16.6%; P<0.001). CONCLUSIONS: ENDOANGEL-CPS could potentially improve the accuracy of colorectal polyp size measurements and size-based surveillance intervals.

Oncogenic and immunological values of RBM34 in osteosarcoma and its pan-cancer analysis.

RNA binding proteins (RBPs) are increasingly recognized as potential factors influencing the advancement, prognostication, and immune response in various solid tumors. Nevertheless, the comprehensive understanding of RBM34's biological mechanisms within the tumor microenvironment remains incomplete, necessitating further systematic pan-cancer investigations to ascertain its diagnostic, prognostic, and immunological significance. In this study, the TCGA, CCLE, HPA, GTEX, and TARGET databases were employed to analyze the expression abundance and subcellular localization of RBM34 in diverse tumor types. Kaplan-Meier survival analyses were used to investigate the impact of RBM34 on clinical prognosis. We implemented the TISIDB portal, CIBERSORT, and ESTIMATE algorithms to assess the correlation between RBM34 expression and immunomodulators, chemokines, and tumor-infiltrating lymphocytes (TILs) in both pan-cancer and osteosarcoma. The CGP database was applied to evaluate the half-maximal inhibitory concentrations of targeted drugs, while TMB, MSI, and MMR were utilized to predict the efficacy of tumor immunotherapy. Furthermore, an RBM34-derived prognostic index (RDPI) was constructed for osteosarcoma patients and linked to outcomes and immune status. Finally, we examined the modulation of RBM34 knockdown on osteosarcoma proliferation and migration capacity. Our results indicate that RBM34 was predominantly localized in the nucleus and differentially expressed in most human cancer types. Kaplan-Meier curve analysis and Cox regression demonstrated that RBM34 expression affected four survival metrics including overall survival (OS) in multiple tumors and was an independent prognostic factor for osteosarcoma. In immunological characterization, RBM34 expression was significantly associated with pan-cancer immunomodulator-related molecules, lymphocyte subpopulation infiltration, and biomarkers of immunotherapy response. Subsequent in vitro experiments provided additional evidence that the suppression of RBM34 impeded the migratory and invasive capabilities of osteosarcoma. Moreover, the utilization of RDPI demonstrated its reliability in prognosticating patient outcomes and estimating the individual immune landscape. Marked differences in multiple TILs (including naive B cells, CD8+ T cells, resting dendritic cells, and activated CD4+ memory T cells) and cancer-associated fibroblast proportion were observed in diverse RDPI score subgroups. Generally, RBM34 exhibited associations with clinical prognosis, immune infiltration, and immunotherapy across various cancer types, and may also serve as a viable therapeutic target for osteosarcoma.

Comprehensive Analysis of a Ferroptosis-Related lncRNA Signature for Predicting Prognosis and Immune Landscape in Osteosarcoma.

Research on the implications of ferroptosis in tumors has increased rapidly in the last decades. There are evidences that ferroptosis is involved in several aspects of cancer biology, including tumor progression, metastasis, immunomodulation, and therapeutic response. Nonetheless, the interaction between ferroptosis-related lncRNAs (FRLs) and the osteosarcoma immune microenvironment is poorly understood. In this study, a risk model composed of FRLs was developed using univariate and LASSO Cox regression analyses. On the basis of this model, FRL scores were calculated to systematically explore the role of the model in predicting the prognosis and immune characteristics of osteosarcoma patients. Survival analysis showed that osteosarcoma samples with lower FRL-score had better overall survival. After predicting the abundance of immune cells in osteosarcoma microenvironment by single-sample gene-set enrichment analysis (ssGSEA) and ESTIMATE analysis, we found that the FRL-score could distinguish immune function, immune score, stromal score, tumor purity, and tumor infiltration of immune cells in different osteosarcoma patients. In addition, FRL-score was also associated with immune checkpoint gene expression and half-maximal inhibitory concentration of chemotherapeutic agents. Finally, we confirmed that knockdown of RPARP-AS1 suppressed the malignant activity of osteosarcoma cells in vitro experiments. In general, the FRL-based prognostic signature could promote our understanding of the immune microenvironment characteristics of osteosarcoma and guide more effective treatment regimens.

Creation of a Yeast Strain with Co-Translationally Acylated Nucleosomes.

Structurally diverse acylations have been identified as post-translational modifications (PTMs) on histone lysine residues, but their functions and regulations remain largely unknown. Interestingly, in nature, a lysine acylation analog, pyrrolysine, is introduced as a co-translational modification (CTM) through genetic encoding. To explore this alternative life form, we created a model organism Saccharomyces cerevisiae containing site-specific lysine CTMs (acetyl-lysine, crotonyl-lysine, or another synthetic analog) at histone H3K56 using non-canonical amino acid mutagenesis to afford a chemically modified nucleosome in lieu of their own in vivo. We further demonstrated that acetylation of histone H3K56 partly tends to provide a more favorable chromatin environment for DNA repair in yeast compared to crotonylation and crosstalk with other PTMs differently. This study provides a potentially universal approach to decipher the consequences of different histone lysine PTMs in eukaryotes.

Integrated analyses of an RNA binding protein-based signature related to tumor immune microenvironment and candidate drugs in osteosarcoma.

OBJECTIVE: Osteosarcoma is the most frequent primary bone malignancy, associated with frequent recurrence and lung metastasis. RNA-binding proteins (RBPs) are pivotal in regulating several aspects of cancer biology. Nonetheless, interaction between RBPs and the osteosarcoma immune microenvironment is poorly understood. We investigated whether RBPs can predict prognosis and immunotherapy response in osteosarcoma patients. METHODS: We constructed an RBP-related prognostic signature (RRPS) by univariate coupled with multivariate analyses and verified the independent prognostic efficacy of the signature. Single-sample Gene Set Enrichment Analysis (ssGSEA) along with ESTIMATE analysis were carried out to investigate the variations in immune characteristics between subgroups with various RRPS-scores. Furthermore, we investigatedpossible small molecule drugs using the connectivity map database and validated the expression of hub RBPs by qRT-PCR. RESULTS: The RRPS, consisting of seven hub RBPs, was an independent prognostic factor compared to traditional clinical features. The RRPS could distinguish immune functions, immune score, stromal score, tumor purity and tumor infiltration by immune cells in different osteosarcoma subjects. Additionally, patients with high RRPS-scores had lower expression of immune checkpoint genes than patients with low RRPS-scores. We finally identified six small molecule drugs that may improve prognosis in osteosarcoma patients and substantiated notable differences in the contents of these RBPs. CONCLUSION: We evaluated the prognostic value and clinical application of an RBPs-based prognostic signature and identified promising biomarkers to predict immune cell infiltration and immunotherapy response in osteosarcoma.

One-pot synthesis of double silane-functionalized carbon dots with tunable emission and excellent coating properties for WLEDs application.

Silane-functionalized carbon dots (SiCDs) can be exploited as effective color converting materials for the solid-state light-emitting devices. However, most of SiCDs reported thus far have shown photoluminescence emissions in the blue and green spectral range, which limit them to construct an efficient white light-emitting diodes (WLEDs) due to the lack of long-wavelength emission. Herein, a series of double silane-functionalized carbon dots (DSiCDs) were prepared via a one-step solvothermal method. The results show that the organic functional group of the silane has great influence on the optical properties of DSiCDs and the number of alkoxy group in the silane has great influence on coating properties of DSiCDs. In addition, the DSiCDs prepared by (3-aminopropyl)triethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine with molar ratio of 7:3 show excellent optical properties with the maximum emission at 608 nm under 570 nm excitation. Furthermore, they can be completely cured within 1 h at room temperature to form fluorescent coating with high stability and strong adhesion to the substrate. Together with their excellent optical and coating properties, they can be directly coated on LED chips to prepare WLEDs, with a CIE coordinate of (0.33,0.31), color rendering index of 81.6, and color temperature of 5774 K.

When Supramolecular Chemistry Meets Chemical Biology: New Strategies to Target Proteins through Host-Guest Interactions.

Supramolecular chemistry for targeting proteins is of great interest for the development of novel approaches to recognize, isolate and control proteins. Taking advantage of chemical biology approaches, such as genetic-code expansion and enzyme-mediated ligation, guest recognition elements can be built into proteins of interest, allowing supramolecular control of protein function and regulation. In this viewpoint article, we will discuss the methods, applications, limitations, and future perspectives of supramolecular chemistry for targeting proteins in a site-specific manner.

A General Supramolecular Approach to Regulate Protein Functions by Cucurbit[7]uril and Unnatural Amino Acid Recognition.

Regulation of specific protein function is of great importance for both research and therapeutic development. Many small or large molecules have been developed to control specific protein function, but there is a lack of a universal approach to regulate the function of any given protein. We report a general host-guest molecular recognition approach involving modification of the protein functional surfaces with genetically encoded unnatural amino acids bearing guest side chains that can be specifically recognized by cucurbit[7]uril. Using two enzymes and a cytokine as models, we showed that the activity of proteins bearing unnatural amino acid could be turned off by host molecule binding, which blocked its functional binding surface. Protein activity can be switched back by treatment with a competitive guest molecule. Our approach provides a general tool for reversibly regulating protein function through molecular recognition and can be expected to be valuable for studying protein functions.

Thermophilic Pyrrolysyl-tRNA Synthetase Mutants for Enhanced Mammalian Genetic Code Expansion.

Genetic code expansion (GCE) is a powerful technique for site-specific incorporation of noncanonical amino acids (ncAAs) into proteins in living cells, which is achieved through evolved aminoacyl-tRNA synthetase mutants. Stability is important for promoting enzyme evolution, and we found that many of the evolved synthetase mutants have reduced thermostabilities. In this study, we characterized two novel pyrrolysyl-tRNA synthetases (PylRSs) derived from thermophilic archaea: Methanosarcina thermophila (Mt) and Methanosarcina flavescens (Mf). Further study demonstrated that the wild-type PylRSs and several mutants were orthogonal and active in both Escherichia coli and mammalian cells and could thus be used for GCE. Compared with the commonly used M. barkeri PylRS, the wild-type thermophilic PylRSs displayed reduced GCE efficiency; however, some of the mutants, as well as some chimeras, outperformed their mesophilic counterparts in mammalian cell culture at 37 °C. Their better performance could at least partially be attributed to the fact that these thermophilic synthetases exhibit a threshold of enhanced stability against destabilizing mutations to accommodate structurally diverse substrate analogues. These were indicated by the higher melting temperatures (by 3-6 °C) and the higher expression levels that were typically observed for the MtPylRS and MfPylRS mutants relative to the Mb equivalents. Using histone H3 as an example, we demonstrated that one of the thermophilic synthetase mutants promoted the incorporation of multiple acetyl-lysine residues in mammalian cells. The enzymes developed in this study add to the PylRS toolbox and provide potentially better scaffolds for PylRS engineering and evolution, which will be necessary to meet the increasing demands for expanded substrate repertoire with better efficiency and specificity in mammalian systems.

An Orthogonal Tyrosyl-tRNA Synthetase/tRNA Pair from a Thermophilic Bacterium for an Expanded Eukaryotic Genetic Code.

The Escherichia coli-derived tyrosyl-tRNA synthetase was the first enzyme engineered for genetic code expansion in a eukaryotic system but can charge only a limited set of structurally simple noncanonical amino acids. In contrast, the thermophilic Methanocaldococcus jannaschii-derived tyrosyl-tRNA synthetase mutants, used in only a prokaryotic system, can charge a surprisingly large set of structurally diverse ncAAs, due to their remarkable structural ability to tolerate mutations. Inspired by this, we characterized a new class of tyrosyl-tRNA synthetase/tRNATyr pairs from thermophilic bacterium Geobacillus stearothermophilus, which is homologous to the E. coli tyrosyl-tRNA synthetase but with better thermostability. This new pair is both orthogonal in mammalian cells and in Saccharomyces cerevisiae for genetic code expansion and can charge a diverse set of ncAAs with a comparable cellular efficiency, better specificity, and lower background, as compared to those of its E. coli homologue. This thermostable enzyme provides an alternative scaffold for synthetase library screening or evolution to genetically encode more structurally complex ncAAs in eukaryotic cells.

Proteomic Identification of Protein Tyrosine Phosphatase and Substrate Interactions in Living Mammalian Cells by Genetic Encoding of Irreversible Enzyme Inhibitors.

Protein tyrosine phosphatases (PTPs) play critical roles in cell signaling pathways, but identification of unknown PTPs for a given substrate in live cells remain technically challenging. Here, we synthesized a series of tyrosine-based irreversible PTP inhibitors and characterized by site-specific encoding on substrate proteins in cells with an expanded genetic code. By fine-tuning the chemical reactivity, we identified optimal active amino acid probes to covalently cross-link a PTP and its substrate both in vitro and in mammalian cells. Using HER2 as an example, we provide first direct evidence of HER2 Y1023 and SHP2 cross-linking in situ in living human cells. Moreover, proteomic analysis using our approach identified PTP1B as a novel phosphatase for HER2 that specifically dephosphorylated pY1221 position, which may shed light on the puzzle of PTP1B's role in HER2 positive breast cancer. This novel method provides a useful tool for dissecting tyrosine phosphoregulation in living cells.

Upconversion effective enhancement by producing various coordination surroundings of rare-Earth ions.

In this manuscript, we present a simple route to enhance upconversion (UC) emission by producing two different coordination sites of trivalent cations in a matrix material and adjusting crystal field asymmetry by Hf(4+) co-doping. A cubic phase, Y3.2Al0.32Yb0.4Er0.08F12, with these structural characteristics was synthesized successfully by introducing a small ion (Al(3+)) into YF3. X-ray diffraction (XRD), nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), X-ray spectroscopy (XPS), and fluorescence spectrophotometry (FS) were employed for its crystalline structure and luminescent property analysis. As a result, the coordination environments of the rare-earth ions were varied more obviously than a hexagonal NaYF4 matrix with the same Hf(4+) co-doping concentration, with vertical comparison, UC luminescent intensities of cubic Y3.2Al0.32Yb0.4Er0.08F12 were largely enhanced (∼32-80 times greater than that of different band emissions), while the maximum enhancement of hexagonal NaYF4 was by a factor of ∼12. According to our experimental results, the mechanism has been demonstrated involving the crystalline structure, crystal field asymmetry, luminescence lifetime, hypersensitive transition, and so on. The study may be helpful for the design and fabrication of high-performance UC materials.

Influences of Structural Properties on Stability of Fullerenols.

Influences of structural properties on the stability of fullerenols are studied using experimental techniques including laser-induced dissociation associated with a time-of-flight measurement, synchrotron radiation XPS, and FT-IR spectroscopy. Stabilities of a family of fullerenols (C60(OH)42, C60(OH)44, C60(OH)30, C60(OH)30, C60(OH)32, and C60(OH)36) as functions of structural parameters-the hydroxyl number, intensity of the impure group, and the ratio of the carbonyl to hydroxyl groups-are investigated. It is found that the molecular stability largely depends on the quantity of impure groups, especially the highly oxygenated carbons in fullerenols, but less on the hydroxyl number. This is different from the previous consideration that the stability of fullerenols largely depends on the hydroxyl number. Previously, to gain the larger solubility required by practical applications, it was suggested to increase the number of the hydroxyl groups. This idea needs to be restudied, because in highly hydroxylated fullerenol molecules, the coinstantaneous formation of a large amount of impure groups is observed. The use of C60(OH) n>36 in practical applications should proceed with caution, since these could lead to unstable open-cage structures. The results reveal a way of controlling the formation of impure groups to gain fullerenols of high stability.