The arginyl-tRNA synthetase (ArgRS) catalyzes the esterification reaction between L-arginine and its cognate tRNA(Arg). Previously reported structures of ArgRS shed considerable light on the tRNA recognition mechanism, while the aspect of amino acid binding in ArgRS remains largely unexplored. Here we report the first crystal structure of E. coli ArgRS (eArgRS) complexed with L-arginine, and a series of mutational studies using isothermal titration calorimetry (ITC). Combined with previously reported work on ArgRS, our results elucidated the structural and functional roles of a series of important residues in the active site, which furthered our understanding of this unique enzyme.
Arginine ; chemistry ; Arginine-tRNA Ligase ; chemistry ; Binding Sites ; Catalytic Domain ; Crystallography, X-Ray ; Escherichia coli ; Ligands ; Mutagenesis, Site-Directed ; Protein Binding ; Protein Conformation ; RNA, Transfer ; chemistry ; Structure-Activity Relationship

Articular cartilage injury is common in orthopedics. Improper exercises and physical trauma can lead to the injury of cartilage. Since articular cartilage lacks blood supply, once damaged, it is difficult for the cartilage to repair itself. If not treated effectively, cartilage injuries will develop into severe osteoarthritis affecting the whole joint. Arthroscopic microfracture technique can achieve better therapeutic effects than regular joint debridement, with simple procedures, minimal invasion, and low cost. However, the microfracture technique is limited by the patients′ age (under 45 years old) and the size of the cartilage defect area (less than 4 cm 2) Additionally, postoperative patients need to conduct strict and long-term rehabilitation trainings. Generally speaking, the short-term prognosis of microfracture is satisfactory. However, the repair tissue is mainly composed of fibrocartilage, which is inferior to hyaline cartilage because of its poor mechanical properties and anti-wear abilities. Therefore, the long-term effect is controversial. To conclude, arthroscopic microfracture is a recommended method for young patients with small cartilage defect areas, but its exact long-term clinical effects still need to be verified by further research. This paper reviews the operation protocol, clinical efficacy, and the mechanism of arthroscopic microfracture surgery, and aims to provides theoretical basis for its application in clinical treatment.

Objective To test the effect of metastasis associated in lung adenocarcinoma transcript 1 ( MALAT1) and／or osimertinib on the proliferation and apoptosis of HCC827 cells, and explore the potential mechanism of MALAT1 induced resistance to osimertinib. Methods We transfected HCC827 cells with LV?vector or LV?over／MALAT1. Stable transfected cells ( HCC827／Vector, HCC827／MALAT1) were selected by adding puromycin. HCC827／MALAT1 cells were further transfected with the shRNA?negative control ( NC) or shRNA?human epidermal growth factor receptor 3 ( ERBB3 ) plasmid. The effects of overexpression of MALAT1, knockdown of ERBB3 and／or osimertinib on the proliferation of HCC827 cells were evaluated by 3?(4,5?dimethyl?2?thiazolyl)?2,5?diphenyl?2H tetrazolium bromide ( MTT) assay. Cell apoptosis induced by MALAT1 overexpression, knockdown of ERBB3 and／or osimertinib treatment were analyzed by flow cytometry analysis. The expressions of EGFR and ERBB3 signal pathway related proteins in HCC827 cells treated with overexpression of MALAT1, knockdown of ERBB3 and／or osimertinib treatment were detected by western blot. Results The MTT assay showed that sensitivity to osimertinib of HCC827／MALAT1 cells were significantly repressed. The 50% inhibitive concentration (IC50 ) of osimertinib ＞4 000 nmol／L in HCC827／MALAT1 cells.However, knockdown of ERBB3 facilitated the anti?proliferation effect of osimertinib, and the IC50 of osimertinib in shRNA?ERBB3 cells was (17.27±3.21) nmol／L. The results of flow cytometry analysis showed that the apoptotic rate of HCC827／MALAT1 cells induced by 10 nmol／L osimertinib was (8.38±0.92)%, significantly lower than ( 27.17± 5.83)% of knockdown of ERBB3 ( P＜0.01). Western blotting showed that the expression of p?ERBB3, p?AKT and p?extracellular regulated protein kinases ( ERK) in HCC827／MALAT1 cells was markedly up?regulated, while the expression of p?epithelial growth factor receptor (EGFR) was inhibited. The expressions of p?ERBB3, p?AKT and p?ERK were marginally affected by osimertinb. However, osimertinib downregulated the expressions of p?EGFR, p?ERBB3, p?AKT and p?ERK in ERBB3 deleted cells. Conclusions MALAT1 confers resistance to osimertinb in HCC827 cells by activating of the ERBB3／PI3K／AKT and ERBB3／MAPK／ERK signaling pathways.

Objective To test the effect of metastasis associated in lung adenocarcinoma transcript 1 ( MALAT1) and／or osimertinib on the proliferation and apoptosis of HCC827 cells, and explore the potential mechanism of MALAT1 induced resistance to osimertinib. Methods We transfected HCC827 cells with LV?vector or LV?over／MALAT1. Stable transfected cells ( HCC827／Vector, HCC827／MALAT1) were selected by adding puromycin. HCC827／MALAT1 cells were further transfected with the shRNA?negative control ( NC) or shRNA?human epidermal growth factor receptor 3 ( ERBB3 ) plasmid. The effects of overexpression of MALAT1, knockdown of ERBB3 and／or osimertinib on the proliferation of HCC827 cells were evaluated by 3?(4,5?dimethyl?2?thiazolyl)?2,5?diphenyl?2H tetrazolium bromide ( MTT) assay. Cell apoptosis induced by MALAT1 overexpression, knockdown of ERBB3 and／or osimertinib treatment were analyzed by flow cytometry analysis. The expressions of EGFR and ERBB3 signal pathway related proteins in HCC827 cells treated with overexpression of MALAT1, knockdown of ERBB3 and／or osimertinib treatment were detected by western blot. Results The MTT assay showed that sensitivity to osimertinib of HCC827／MALAT1 cells were significantly repressed. The 50% inhibitive concentration (IC50 ) of osimertinib ＞4 000 nmol／L in HCC827／MALAT1 cells.However, knockdown of ERBB3 facilitated the anti?proliferation effect of osimertinib, and the IC50 of osimertinib in shRNA?ERBB3 cells was (17.27±3.21) nmol／L. The results of flow cytometry analysis showed that the apoptotic rate of HCC827／MALAT1 cells induced by 10 nmol／L osimertinib was (8.38±0.92)%, significantly lower than ( 27.17± 5.83)% of knockdown of ERBB3 ( P＜0.01). Western blotting showed that the expression of p?ERBB3, p?AKT and p?extracellular regulated protein kinases ( ERK) in HCC827／MALAT1 cells was markedly up?regulated, while the expression of p?epithelial growth factor receptor (EGFR) was inhibited. The expressions of p?ERBB3, p?AKT and p?ERK were marginally affected by osimertinb. However, osimertinib downregulated the expressions of p?EGFR, p?ERBB3, p?AKT and p?ERK in ERBB3 deleted cells. Conclusions MALAT1 confers resistance to osimertinb in HCC827 cells by activating of the ERBB3／PI3K／AKT and ERBB3／MAPK／ERK signaling pathways.

The stability of vaccines has a major impact on the success of immunization programmes worldwide. Stability evaluation is a vital part of the assessment of the vaccine quality and safety. It should be regarded as a continuous process from the development of the vaccine through licensing to post-licensure monitoring. To ensure the quality of the vaccine, related guidelines were issued by both World Health Organization and Chinese regulatory authority. This paper reviews the progress of relevant guidelines and studies for providing the stability considerations of vaccine.

Microglia/physiology* ; Neurons/physiology* ; Cells, Cultured

Objective:To evaluate the clinical efficacy of nasal pedicle tissue flap based on nasal blood supply in the reconstruction of nasal skull base defects.Methods:A retrospective analysis was conducted on 138 clinical cases of skull base tumors and cerebrospinal fluid rhinorrhea treated at the Department of Otolaryngology, Head and Neck Surgery at Xiangya Hospital of Central South University from March 2017 to March 2023. A total of 79 males and 59 females were enrolled, aged from 8 to 82 years, with a median age of 51 years, including 108 patients (78.3%) with skull base tumors and 30 patients (21.7%) with cerebrospinal fluid rhinorrhea (and/or meningoencephalocele). During the surgery, 88 cases (63.8%) were repaired with nasal septal mucosal flaps pedicled with the posterior nasal septal artery, 14 cases (10.1%) with mucosal flaps pedicled with the anterior ethmoidal artery on the lateral wall of the nasal cavity, 6 cases (4.3%) with mucosal flaps pedicled with the posterior lateral nasal artery on the lateral wall and nasal floor, 12 cases (8.7%) with mucosal flaps pedicled with the anterior ethmoidal artery and posterior ethmoidal artery, and 18 cases (13.0%) with nasal septal mucosal extension flaps pedicled with the sphenopalatine artery or internal maxillary artery. Patients were followed up for 12 to 72 months postoperatively. Endoscopic examination or skull base enhanced MRI was performed to assess the growth and tumor recurrence in the skull base repair area. The t-test was used for statistical analysis.Results:Among 138 patients, primary repair was successful in 133 patients (96.4%), while 5 patients (3.6%) experienced postoperative cerebrospinal fluid rhinorrhea. These 5 patients all underwent nasal septal mucosal flap repair with the posterior nasal septal artery as the pedicle. Complications included 1 case of mucosal flap necrosis, 1 case of mucosal flap central perforation, and 3 cases of mucosal flap survival peripheral leakage, of which were all successfully treated with a second repair.Conclusion:The use of nasal pedicle mucosal flap based on nasal blood supply is a reliable, safe, and effective technique for repairing skull base defects.

Objective: To test the effect of metastasis associated in lung adenocarcinoma transcript 1 (MALAT1) and/or osimertinib on the proliferation and apoptosis of HCC827 cells, and explore the potential mechanism of MALAT1 induced resistance to osimertinib. Methods: We transfected HCC827 cells with LV-vector or LV-over/MALAT1. Stable transfected cells (HCC827/Vector, HCC827/MALAT1) were selected by adding puromycin. HCC827/MALAT1 cells were further transfected with the shRNA-negative control (NC) or shRNA-human epidermal growth factor receptor 3 (ERBB3) plasmid. The effects of overexpression of MALAT1, knockdown of ERBB3 and/or osimertinib on the proliferation of HCC827 cells were evaluated by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay. Cell apoptosis induced by MALAT1 overexpression, knockdown of ERBB3 and/or osimertinib treatment were analyzed by flow cytometry analysis. The expressions of EGFR and ERBB3 signal pathway related proteins in HCC827 cells treated with overexpression of MALAT1, knockdown of ERBB3 and/or osimertinib treatment were detected by western blot. Results: The MTT assay showed that sensitivity to osimertinib of HCC827/MALAT1 cells were significantly repressed. The 50% inhibitive concentration (IC₅₀) of osimertinib >4 000 nmol/L in HCC827/MALAT1 cells. However, knockdown of ERBB3 facilitated the anti-proliferation effect of osimertinib, and the IC₅₀ of osimertinib in shRNA-ERBB3 cells was (17.27±3.21) nmol/L. The results of flow cytometry analysis showed that the apoptotic rate of HCC827/MALAT1 cells induced by 10 nmol/L osimertinib was (8.38±0.92)%, significantly lower than (27.17±5.83)% of knockdown of ERBB3 (P<0.01). Western blotting showed that the expression of p-ERBB3, p-AKT and p-extracellular regulated protein kinases (ERK) in HCC827/MALAT1 cells was markedly up-regulated, while the expression of p-epithelial growth factor receptor (EGFR) was inhibited. The expressions of p-ERBB3, p-AKT and p-ERK were marginally affected by osimertinb. However, osimertinib downregulated the expressions of p-EGFR, p-ERBB3, p-AKT and p-ERK in ERBB3 deleted cells. Conclusions MALAT1 confers resistance to osimertinb in HCC827 cells by activating of the ERBB3/PI3K/AKT and ERBB3/MAPK/ERK signaling pathways.