T7 RNA polymerase (T7 RNAP) is one of the simplest known RNA polymerases. Its unique structural features make it a critical model for studying the mechanisms of RNA synthesis. This review systematically examines the static crystal structure of T7 RNAP, beginning with an in-depth examination of its characteristic “thumb”, “palm”, and “finger” domains, which form the classic “right-hand-like” architecture. By detailing these structural elements, this review establishes a foundation for understanding the overall organization of T7 RNAP. This review systematically maps the functional roles of secondary structural elements and their subdomains in transcriptional catalysis, progressively elucidating the fundamental relationships between structure and function. Further, the intrinsic flexibility of T7 RNAP and its applications in research are also discussed. Additionally, the review presents the structural diagrams of the enzyme at different stages of the transcription process, and through these diagrams, it provides a detailed description of the complete transcription process of T7 RNAP. By integrating structural dynamics and kinetics analyses, the review constructs a comprehensive framework that bridges static structure to dynamic processes. Despite its advantages, T7 RNAP has a notable limitation: it generates double-stranded RNA (dsRNA) as a byproduct. The presence of dsRNA not only compromises the purity of mRNA products but also elicits nonspecific immune responses, which pose significant challenges for biotechnological and therapeutic applications. The review provides a detailed exploration of the mechanisms underlying dsRNA formation during T7 RNAP catalysis, reviews current strategies to mitigate this issue, and highlights recent progress in the field. A key focus is the semi-rational design of T7 RNAP mutants engineered to minimize dsRNA generation and enhance catalytic performance. Beyond its role in transcription, T7 RNAP exhibits rapid development and extensive application in fields, including gene editing, biosensing, and mRNA vaccines. This review systematically examines the structure-function relationships of T7 RNAP, elucidates the mechanisms of dsRNA formation, and discusses engineering strategies to optimize its performance. It further explores the engineering optimization and functional expansion of T7 RNAP. Furthermore, this review also addresses the pressing issues that currently need resolution, discusses the major challenges in the practical application of T7 RNAP, and provides an outlook on potential future research directions. In summary, this review provides a comprehensive analysis of T7 RNAP, ranging from its structural architecture to cutting-edge applications. We systematically examine: (1) the characteristic right-hand domains (thumb, palm, fingers) that define its minimalistic structure; (2) the structure-function relationships underlying transcriptional catalysis; and (3) the dynamic transitions during the complete transcription cycle. While highlighting T7 RNAP’s versatility in gene editing, biosensing, and mRNA vaccine production, we critically address its major limitation—dsRNA byproduct formation—and evaluate engineering solutions including semi-rationally designed mutants. By synthesizing current knowledge and identifying key challenges, this work aims to provide novel insights for the development and application of T7 RNAP and to foster further thought and progress in related fields.

BACKGROUND: Temozolomide (TMZ) resistance is a significant challenge in treating glioblastoma (GBM). Collagen remodeling has been shown to be a critical factor for therapy resistance in other cancers. This study aimed to investigate the mechanism of TMZ chemoresistance by GBM cells reprogramming collagens. METHODS: Key extracellular matrix components, including collagens, were examined in paired primary and recurrent GBM samples as well as in TMZ-treated spontaneous and grafted GBM murine models. Human GBM cell lines (U251, TS667) and mouse primary GBM cells were used for in vitro studies. RNA-sequencing analysis, chromatin immunoprecipitation, immunoprecipitation-mass spectrometry, and co-immunoprecipitation assays were conducted to explore the mechanisms involved in collagen accumulation. A series of in vitro and in vivo experiments were designed to assess the role of the collagen regulators prolyl 4-hydroxylase subunit alpha 1 (P4HA1) and yes-associated protein (YAP) in sensitizing GBM cells to TMZ. RESULTS: This study revealed that TMZ exposure significantly elevated collagen type I (COL I) expression in both GBM patients and murine models. Collagen accumulation sustained GBM cell survival under TMZ-induced stress, contributing to enhanced TMZ resistance. Mechanistically, P4HA1 directly binded to and hydroxylated YAP, preventing ubiquitination-mediated YAP degradation. Stabilized YAP robustly drove collagen type I alpha 1 ( COL1A1) transcription, leading to increased collagen deposition. Disruption of the P4HA1-YAP axis effectively reduced COL I deposition, sensitized GBM cells to TMZ, and significantly improved mouse survival. CONCLUSION P4HA1 maintained YAP-mediated COL1A1 transcription, leading to collagen accumulation and promoting chemoresistance in GBM.
Temozolomide ; Humans ; Glioblastoma/drug therapy* ; Animals ; Mice ; Cell Line, Tumor ; Drug Resistance, Neoplasm/genetics* ; YAP-Signaling Proteins ; Hydroxylation ; Dacarbazine/pharmacology* ; Adaptor Proteins, Signal Transducing/metabolism* ; Transcription Factors/metabolism* ; Collagen/biosynthesis* ; Collagen Type I/metabolism* ; Prolyl Hydroxylases/metabolism* ; Antineoplastic Agents, Alkylating/therapeutic use*

OBJECTIVES: To identify risk factors contributing to prolonged postoperative length of stay (LOS) in very elderly patients following hip fracture surgery, with a focus on postoperative complications and the impact of different anesthesia approaches. METHODS: This retrospective single-center cohort study enrolled patients aged 90 years or older who underwent hip fracture surgery at Peking Union Medical College Hospital between January 31, 2013 and December 31, 2023. Relevant perioperative data were collected. The primary outcome was postoperative LOS, and the study cohort was divided into two groups: postoperative LOS ≤ 7 days and LOS > 7 days. Logistic regression was performed to identify factors related to prolonged postoperative LOS. RESULTS: A total of 155 patients were included. The average age was 92.7 ± 2.6 years. There were 73 (47%) patients with postoperative LOS > 7 days. Postoperative pneumonia was the only factor associated with a prolonged postoperative LOS (OR = 2.12, 95% CI [1.09, 4.16], P = 0.028). Neither the type of anesthesia (regional vs. general anesthesia, OR = 1.00, 95% CI [0.53, 1.90], P = 0.993) nor the method of airway management (laryngeal mask ventilation vs. spontaneous breathing, OR = 1.46, 95% CI [0.58, 3.76], P = 0.424; endotracheal intubation vs. spontaneous breathing, OR = 0.82, 95% CI [0.39, 1.69], P = 0.592) showed a significant association with a prolonged postoperative LOS. Preoperative chronic obstructive pulmonary disease (OR = 2.78, 95% CI [1.05, 7.65], P = 0.040) and preoperative neutrophil count (OR = 1.13, 95% CI [1.01, 1.26], P = 0.029) were both significantly associated with the occurrence of postoperative pneumonia, while anesthesia type and airway management method were not. CONCLUSIONS Postoperative pneumonia was associated with prolonged postoperative LOS in very elderly patients undergoing hip fracture surgery, whereas anesthesia types and airway management methods show no association with prolonged postoperative LOS or postoperative pneumonia. Preoperative comorbidities, especially respiratory conditions and systemic inflammation, potentially play a substantial role in postoperative recovery.
Humans ; Hip Fractures/surgery* ; Aged, 80 and over ; Risk Factors ; Length of Stay ; Female ; Male ; Retrospective Studies ; Postoperative Complications/etiology*

This study was conducted retrospectively on a cohort of 68 patients with steroid 5 α-reductase 2 (SRD5A2) deficiency and 46,XY disorders of sex development (DSD). Whole-exon sequencing revealed 28 variants of SRD5A2 , and further analysis identified seven novel mutants. The preponderance of variants was observed in exon 1 and exon 4, specifically within the nicotinamide adenine dinucleotide phosphate (NADPH)-binding region. Among the entire cohort, 53 patients underwent initial surgery at Sichuan Provincial People's Hospital (Chengdu, China). The external genitalia scores (EGS) of these participants varied from 2.0 to 11.0, with a mean of 6.8 (standard deviation [s.d.]: 2.5). Thirty patients consented to hormone testing. Their average testosterone-to-dihydrotestosterone (T/DHT) ratio was 49.3 (s.d.: 23.4). Genetic testing identified four patients with EGS scores between 6 and 9 as having this syndrome; and their T/DHT ratios were below the diagnostic threshold. Furthermore, assessments conducted using the crystal structure of human SRD5A2 have provided insights into the potential pathogenic mechanisms of these novel variants. These mechanisms include interference with NADPH binding (c.356G>C, c.365A>G, c.492C>G, and c.662T>G) and destabilization of the protein structure (c.727C>T). The c.446-1G>T and c.380delG variants were verified to result in large alterations in the transcripts. Seven novel variations were identified, and the variant database for the SRD5A2 gene was expanded. These findings contribute to the progress of diagnostic and therapeutic approaches for individuals with SRD5A2 deficiency.
Humans ; 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/genetics* ; Disorder of Sex Development, 46,XY/blood* ; Male ; Membrane Proteins/genetics* ; Child, Preschool ; Child ; Retrospective Studies ; Adolescent ; Female ; Mutation ; Testosterone/blood* ; Infant ; Dihydrotestosterone/blood*

Objective:To investigate the efficacy and safety of bendamustine combined with anti-CD20 monoclonal antibody in the first-line treatment of older patients with indolent B-cell non-Hodgkin lymphoma (B-iNHL) .Methods:The clinical data of 159 patients with B-iNHL enrolled in 16 hospitals from Jiangsu Cooperative Lymphoma Group from December 1, 2019, to April 20, 2024, were analyzed for regimen efficacy and safety. Bendamustine plus rituximab (BR) and bendamustine plus obinutuzumab (BG) were administered to 139 (87.4% ) and 20 (12.6% ) patients, respectively.Results:Among the 159 patients, 101 (63.5% ) were male and 58 (36.5% ) were female, with a median age of 69 years (range: 60–84). Efficacy could be assessed in 138 (86.8% ) patients. The efficacy assessment demonstrated that the overall response rate was 92.0% with complete and partial remissions in 75 (54.3% ) and 52 (37.7% ) cases, respectively. With a median follow-up of 24 months (range: 4–64), the progression-free survival rate was (87.5 ± 3.0) % and the overall survival rate was (83.2 ± 3.3) %. Of the 27 patients who died, 6 (22.2% ) died due to disease progression. The mean applied dose of bendamustine per cycle was 73.0 (50.8–89.7) mg/m 2 per day, administered on days 1 and 2. Adverse events of grade 3 or higher were reported in 53 (33.3% ) patients, with infection (30 cases,18.9% ) and neutropenia (24 cases, 15.1% ) demonstrating the highest incidence. Conclusion:Bendamustine combined with anti-CD20 monoclonal antibody demonstrated good efficacy and is well-tolerated in the first-line treatment of elderly patients with B-iNHL.

OBJECTIVE: CRISPR-Cas protects bacteria from exogenous DNA invasion and is associated with bacterial biofilm formation and pathogenicity. METHODS: We analyzed the type I-F CRISPR-Cas system of Legionella pneumophila WX48, including Cas1, Cas2-Cas3, Csy1, Csy2, Csy3, and Cas6f, along with downstream CRISPR arrays. We explored the effects of the CRISPR-Cas system on the in vitro growth, biofilm-forming ability, and pathogenicity of L. pneumophila through constructing gene deletion mutants. RESULTS: The type I-F CRISPR-Cas system did not affect the in vitro growth of wild-type or mutant strains. The biofilm formation and intracellular proliferation of the mutant strains were weaker than those of the wild type owing to the regulation of type IV pili and Dot/Icm type IV secretion systems. In particular, Cas6f deletion strongly inhibited these processes. CONCLUSION The type I-F CRISPR-Cas system may reduce biofilm formation and intracellular proliferation in L. pneumophila.
Legionella pneumophila/pathogenicity* ; CRISPR-Cas Systems ; Biofilms/growth & development* ; Phenotype ; Bacterial Proteins/metabolism* ; Gene Deletion

Objective To compare the application effects of plankton multiplex polymerase chain reac-tion-capillary electrophoresis(PCR-CE),SYBR Green Ⅰ real-time quantitative PCR(qPCR)and microwave digestion-vacuum filtration-automated scanning electron microscopy(MD-VF-Auto SEM)in the diagnosis of drowning.Methods Lung,liver and kidney tissues from 212 drowned corpses and 30 non-drowned corpses were examined respectively by the three drowning-related plankton testing methods,and the detection rates of plankton in each tissue by three methods were compared.Results In drowned corpses,the total detection rates of PCR-CE,qPCR,and MD-VF-Auto SEM were 93.9%,96.2%,and 95.3%,respectively,with no statistically significant difference(P>0.05).The detection rate of lung tissue by MD-VF-Auto SEM(100%)was higher than those of PCR-CE and qPCR(P<0.05),and there was no significant difference in the detection rates of the three methods in liver or kidney tissues(P>0.05).In non-drowning corpses,a small number of diatoms(less than 10 cells/10 g)were detected by MD-VF-Auto SEM method,only in liver and kidney tissues,while the other two methods yielded negative results for all tissues.Conclusion All three methods have good efficacy in the examination of drowned corpses.The MD-VF-Auto SEM method directly observes diatom morpho-logical characteristics through scanning electron microscopy,and the qualitative and quantitative analy-ses are intuitive and accurate.It has great advantages in the examination of difficult degradation samples.The PCR-CE method and qPCR method have a low sample demand(0.5 g),are easy to operate and have short detection time(4-7 h).They are easy to be applied in the grassroots depart-ments and are suitable for the rapid determination of drowned corpses in routin cases.The combina-tion of the two DNA methods with the MD-VF-Auto SEM method can increase the detection rate of plankton,ensuring the reliability of examination results.This combined use is of significant importance in the application of drowning diagnosis.

Objectives:To investigate the impact of the Micra AV leadless pacemaker on cardiac function.Methods:A total of 76 patients who received the implantation of Micra AV leadless pacemaker due to sick sinus syndrome or atrioventricular block at Ruijin Hospital,Shanghai Jiao Tong University School of Medicine from September 2022 to April 2023 were included in this study.Among them,26 patients(34.2%)had sick sinus syndrome,and 50 patients(65.8%)had atrioventricular block.The patients were followed up for 1 year postoperatively.Cardiac function was evaluated by echocardiography,and the parameters of the pacemaker were collected through the outpatient clinic programming system.Results:After a follow-up of 120(87,181)days,compared with the preoperative state,the left ventricular ejection fraction(LVEF)decreased postoperatively([66.6±5.6]%vs.[63.8±5.2]%,P<0.001),and the cardiac output increased[(4.3±1.2)L/min vs.(5.3±1.5)L/min,P<0.001].There were no statistically significant differences in various cardiac function indexes of patients with sick sinus syndrome between the postoperative and preoperative states(all P>0.05).Compared with the preoperative state,in patients with atrioventricular block,the LVEF decreased postoperatively([67.0±5.1]%vs.[63.4±4.4]%,P<0.001),the cardiac output increased([4.2±1.1]L/min vs.[5.2±1.2]L/min,P<0.001),and the left ventricular end-diastolic diameter decreased[(49.9±5.4)mm vs.(48.6±5.0)mm,P=0.044].Firth's logistic regression analysis indicated that the preoperative LVEF(for every 1%increase,OR=1.56,95%CI:1.12-2.17,P=0.001),stroke volume(for every 1 ml increase,OR=1.15,95%CI:1.04-1.28,P=0.001),body mass index(for every 1 kg/m2 increase,OR=1.49,95%CI:1.02-2.17,P=0.020),and hypertension(OR=12.71,95%CI:1.11-145.13,P=0.039)were independent risk factors for the decrease in LVEF after surgery in patients with atrioventricular block.After the implantation of the MciraTM AV leadless pacemaker,the overall atrioventricular synchrony rate was 81.2%(68.8%,89.0%).The atrioventricular synchrony rates of patients with sick sinus syndrome and those with atrioventricular block were 70.6%(59.5%,83.4%)and 82.4%(74.2%,89.3%)respectively(P<0.05).Firth's logistic regression analysis indicated that sick sinus syndrome(OR=0.26,95%CI:0.07-0.89,P=0.029)and preoperative LVEF(for every 1%increase,OR=1.18,95%CI:1.03-1.35,P=0.015)were independent predictive factors for the atrioventricular synchrony rate>80%.Conclusions:There are differences in the impacts of the Micra AV leadless pacemaker on the LVEF and atrioventricular synchrony rate between patients with sick sinus syndrome and those with atrioventricular block.The preoperative LVEF,stroke volume,body mass index,and hypertension have independent predictive effects on the decrease in postoperative LVEF in patients with atrioventricular block.Sick sinus syndrome and preoperative LVEF are independent predictive factors for the atrioventricular synchrony rate>80%after surgery.

Objective:To establish a stable rat model of sequelae of pelvic inflammatory disease(SPID)with clinical characteristics,and to provide a reliable experimental model for the study of the pharmcological effect and mechanism of SPID.Methods:Twenty-four 7-week-old SD rats were divided into sham operation group,model-A(108 cfu/mL mixed bacterial solution,0.2 mL),model-B(109 cfu/mL mixed bacterial solution 0.2 mL),and model-C(108 cfu/mL E.coli 0.2 mL).The weight of the rat's uterine was weighed and the uterine index was calculated.The automatic hematology analyzer was used to detect the blood routine;hematoxylin-eosin staining(HE)and masson staining were used to detect uterine pathlogical changes in rats.Enzyme-linked immunosorbent assay(ELISA)was used to detect interleukin-1β(IL-1β),interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α)in rat uterine tissue homogenates.Western blot was used to detect the expression of proteins related to NF-κB signaling pathway.Results:Compared with the sham operation group,the uterine index of model-A,model-B,and model-C were significantly increased(P＜0.05,P＜0.01).The levels of WBC and NE in the model-A increased significantly(P＜0.01).The level of LY in model-B decreased significantly(P＜0.01).The levels of IL-1β,TNF-α in model-A,model-B,and model-C were significantly increased(P＜0.01).The levels of IL-6 in model-A and model-B were significantly increased(P＜0.05,P＜0.01).The collagen volume fraction of model-A and model-B were significantly increased(P＜0.01).Mechanism study indicates that the expression levels of p-IKKβ/IKKβ,p-IκBα/IκBα and p-p65/p65 in model-A were significantly increased(P＜0.01),and the expression levels of IκBα/β-actin were significantly decreased(P＜0.01).The expression level of p-IKKβ/IKKβ in model-B was significantly increased(P＜0.01).Conclusions:A stable rat model of SPID that conforms to clinical characteristics can be successfully constructed by combining 0.2 mL of mixed bacterial solution with a concentration of 108 cfu/mL and mechanical injury.This modeling method intervened in the expression of the NF-κB inflammatory signaling pathway.