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.

[摘 要] 目的：探讨富含丝氨酸/精氨酸剪接因子7（SRSF7）对肝细胞癌（HCC）细胞HepG2增殖、迁移和侵袭的影响及其可能机制。方法：通过癌症基因组图谱（TCGA）和Kaplan-Meier Plotter在线分析SRSF7在HCC和癌旁组织中的差异表达及其与患者预后的关系。常规培养HepG2细胞，用转染试剂将SRSF7 RNA敲减序列（siSRSF7#1和siSRSF7#2）、对照序列（NC）、SRSF7过表达载体（hSRSF7-oe）和对照载体（hSRSF7-nc）转染至HepG2细胞中，实验分为NC组、siSRSF7#1组、siSRSF7#2组、NC + hSRSF7-nc组、siSRSF7 + hSRSF7-nc组和siSRSF7 + hSRSF7-oe组。通过qPCR和WB法检测各组HepG2细胞中SRSF7 mRNA和蛋白的表达，MTS实验、平板克隆形成实验、划痕愈合实验、Transwell小室实验分别检测各组HepG2细胞的增殖、迁移和侵袭的能力。WB法检测各组HepG2细胞中JAK1/STAT3信号通路的相关蛋白的表达。结果：数据库数据分析显示SRSF7 mRNA在HCC组织中呈高表达（P < 0.001），SRSF7 mRNA高表达与HCC患者不良预后有关联（P < 0.05）。敲减SRSF7后，HepG2细胞的增殖、迁移和侵袭能力均显著下降（均P < 0.01）。敲减SRSF7组细胞中JAK1和STAT3磷酸化水平显著降低（均P < 0.05），同时过表达SRSF7后，JAK1和STAT3磷酸化水平又明显升高（均P < 0.05）。结论：SRSF7在HCC组织中呈高表达，其可能通过调控JAK1/STAT3信号通路促进HepG2细胞的增殖、迁移和侵袭。

The Piezo protein is a non-selective mechanosensitive cation channel that exhibits sensitivity to mechanical stimuli such as pressure and shear stress. It converts mechanical signals into bioelectric activity within cells, thus triggering specific biological responses. In the digestive system, Piezo protein plays a crucial role in maintaining normal physiological activities, including digestion, absorption, metabolic regulation, and immune modulation. However, dysregulation in Piezo protein expression may lead to the occurrence of several pathological conditions, including visceral hypersensitivity, impairment of intestinal mucosal barrier function, and immune inflammation.Therefore, conducting a comprehensive review of the physiological functions and pathological roles of Piezo protein in the digestive system is of paramount importance. In this review, we systematically summarize the structural and dynamic characteristics of Piezo protein, its expression patterns, and physiological functions in the digestive system. We particularly focus on elucidating the mechanisms of action of Piezo protein in digestive system tumor diseases, inflammatory diseases, fibrotic diseases, and functional disorders. Through the integration of the latest research findings, we have observed that Piezo protein plays a crucial role in the pathogenesis of various digestive system diseases. There exist intricate interactions between Piezo protein and multiple phenotypes of digestive system tumors such as proliferation, apoptosis, and metastasis. In inflammatory diseases, Piezo protein promotes intestinal immune responses and pancreatic trypsinogen activation, contributing to the development of ulcerative colitis, Crohn’s disease, and pancreatitis. Additionally, Piezo1, through pathways involving co-action with the TRPV4 ion channel, facilitates neutrophil recruitment and suppresses HIF-1α ubiquitination, thereby mediating organ fibrosis in organs like the liver and pancreas. Moreover, Piezo protein regulation by gut microbiota or factors like age and gender can result in increased or decreased visceral sensitivity, and alterations in intestinal mucosal barrier structure and permeability, which are closely associated with functional disorders like irritable bowel sydrome (IBS) and functional consitipaction (FC). A thorough exploration of Piezo protein as a potential therapeutic target in digestive system diseases can provide a scientific basis and theoretical support for future clinical diagnosis and treatment strategies.

Objective To summarize the acupoints and parameters commonly used in the treatment of vascular cognitive impairment(VCI)by electro-acupuncture(EA)through the visual data mining technique to provide a reference basis for clinical treatment.Methods The clinical studies of EA on the treatment of VCI were searched in CNKI,Wanfang,VIP,CBM,PubMed,Embase,Cochrane Library,web of science and other major databases.The literature is managed by Note Express and the database is established by Excel.The frequency of selected acupoints,frequency,meridian tropism,parameter frequency and frequency of used acupoints are counted.Factor analysis is carried out by SPSS 21.0 software.SPSS Modeler 18.3 software is used to analyze association rules and co-occurrence network,and the analysis results are visualized by Cytoscape 3.9.1 software.Results Finally,155 papers were included,containing 155 acupoint prescriptions and 157 parameter prescriptions.Acupoint prescriptions involved 100 acupoints with a total frequency of 856 times;parameter prescriptions involved 33 parameters with a total frequency of 788 times.Conclusion At present,there is a big difference between the clinical studies,and there is no recognized acupoint and parameter for EA treatment of VCI.By further summarizing the law of EA acupuncture point and parameter,the study has sorted out the law of commonly used acupoints,meridian tropism,compounding and parameter selection for EA treatment of VCI.It was concluded that the selection of acupoints mainly started from the three aspects of deficiency,phlegm and stasis,focusing on the combination of local and distal selection of acupoints,through the identification of internal organs and meridians,to achieve the simultaneous regulation of the heart,spleen and kidney,and to take into account both the symptoms and the root cause,and to play the roles of opening the orifices to wake up mind,calming mind and benefiting intellect,strengthening the spleen and tonifying the kidneys,and invigorating blood circulation to remove stasis.The parameters of EA are recommended to be sparse and dense wave,low frequency,as tolerated by the patient,30 minutes/times,1 time/day,5 times/week as the main combinations,which can provide a certain reference basis for clinical decision-making.

Objective:To provide reference for hospital drug selection and clinical rational drug selection,through evaluating the nutritional value of six commonly used balanced compound amino acid injection (BCAA) in clinical practice,including 18AA (250 mL:12.5 g),18AA-I (250 mL:17.5 g),18AA-Ⅱ(250 mL:21.25 g),18AA-IV (250 mL:8.7 g),18AA-V (250 mL:8.06 g),and 18AA-V-SF (250 mL:8.06 g). Methods:Based on the whole egg protein model,the nutritional value of six varieties of BCAA from two aspects were evaluated,including the first limiting amino acid chemical score (CS),value of essential amino acid (EAA) and the comprehensive quality of total EAA (both essential amino acid index and closeness to standard protein). Results:The first limiting amino acid CS value from high to low was 18AA-Ⅱ>18AA>18AA-V=18AA-V-SF>18AA-I=18AA-Ⅳ. Total EAA comprehensive quality:the essential amino acid index from high to low was 18AA-Ⅱ>18AA>18AA-I>18AA-Ⅳ>18AA-V=18AA-V-SF. The closeness to whole egg protein from high to low was 18AA-Ⅱ=18AA=18AA-I>18AA-Ⅳ>18AA-V=18AA-V-SF. Ultimately,the nutritional value of the 6 varieties of BCAA decreased from high to low:18AA-Ⅱ>18AA>18AA-I>18AA-Ⅳ>18AA-V=18AA-V-SF. Conclusions:Among the six varieties of BCAA,18AA-Ⅱ has the highest nutritional value and the highest amino acid content in the same liquid volume,making it the preferred drug for patients with normal liver and kidney function.

Objective To evaluate the protective effect and underlying mechanism of ulinastatin on hepatic ischemia-reperfusion injury.Methods Twenty-four male SD rats were divided into three groups:sham operation group(Sham group),hepatic ischemia-reperfusion injury group(HIRI group)and hepatic ischemia-reperfusion injury+ulinastatin pretreatment group(HIRI+UTI group),with 8 rats in each group.The HIRI rat models were established by occluding hepatic portal vein and hepatic artery for 1 h.In the HIRI+UTI group,the rats were intraperitoneally injected with ulinastatin at 30 min before model establishment,and an equivalent amount of normal saline was given in the Sham and HIRI groups.The rats were sacrificed at 6 h after model establishment.Serum samples were collected to detect alanine aminotransferase(ALT)and aspartate aminotransferase(AST)levels.Pathological changes of liver tissues were observed by hematoxylin-eosin(HE)staining.Ultrastructural changes of mitochondria in liver tissues were observed by transmission electron microscopy.The expression of glutathione peroxidase 4(GPX4)was determined by immunofluorescent staining.The contents of malondialdehyde(MDA),glutathione(GSH),Fe,reactive oxygen species(ROS)and GPX4 were detected.The expression levels of GPX4 and acyl-CoA synthetase long-chain family 4(ACSL4)messenger RNA(mRNA)and proteins in liver tissue were measured.Results Compared with the Sham group,serum ALT and AST levels were up-regulated,pathological changes such as congestion,hepatocyte necrosis and abnormal hepatic lobule structure were observed,pathological score was increased,the mitochondria shrank,the membrane density was increased,the mitochondrial crest was damaged or even absent,the contents of ROS,MDA and Fe were elevated,the GSH content was decreased,the fluorescent intensity of GPX4 was weakened,the relative expression levels of ACSL4 mRNA and protein were up-regulated,and the relative expression levels of GPX4 mRNA and protein were down-regulated in the HIRI group(all P＜0.05).Compared with the HIRI group,serum ALT and AST levels were down-regulated,liver tissue injury was alleviated,pathological score was decreased,mitochondrial shrinkage and crest breakage were mitigated,the contents of ROS,MDA and Fe were down-regulated,the GSH content was up-regulated,the fluorescent intensity of GPX4 was enhanced,the relative expression levels of ACSL4 mRNA and protein were down-regulated,and the relative expression levels of GPX4 mRNA and protein were up-regulated in the HIRI+UTI group(all P＜0.05).Conclusions Ulinastatin may alleviate hepatic ischemia-reperfusion injury in rats probably through inhibiting ferroptosis.

Objective To evaluate the inhibitory effects of infigratinib and its pharmacologically active metabolites,BHS697 and CQM157,on cytochrome P450(CYPs)and UDP-glucuronosyltransferases(UGTs)in rat liver microsomes.Methods By adopting in vitro incubation method,the tested compounds(infigratinib,BHS697 or CQM157)and rat liver microsomes were incubated with the specific probe substrates of CYP2B6,CYP2C8,CYP2C9,CYP2C19,CYP2D6,CYP3 A4,respectively,or the specific probe substrates of UGT1A1,UGT1A3,UGT1A6,UGT1A9,UGT2B7,respectively.The production of characteristic metabolites was detected by high performance liquid chromatography-tandem mass spectrometry.The half maximal inhibitory concentration(IC50)and inhibition constant(Ki)were calculated by GraphPad Prism 8.0.Results Infigratinib,BHS697 and CQM157 weakly inhibited CYP2B6,CYP2C8,CYP2C9,CYP2C19,CYP2D6,CYP3 A4 and UGT1A6,UGT2B7 in rat liver microsomes,with IC50 values all more than 10 μmol·L-1,and moderately inhibited UGT1Al with IC50 values of 2.70,3.17,7.43 μmol·L-,respectively.Infigratinib had a moderate inhibitory effect on UGT1A9 and CQM157 had a moderate inhibitory effect on UGTIA3,with IC50 values of 5.61 and 9.57 μmol·L-1,respectively.The reversible inhibition analysis showed that infigratinib,BHS697 and CQM157 all non-competitively inhibited UGTIA1,with Ki values of 1.83,2.51 and 5.84 μmol·L-1,respectively.Conclusion Infigratinib had moderate inhibitory effects on UGT1A1 and UGT1A9 in rat liver microsomes and its pharmacologically active metabolites,BHS697 and CQM157,also had moderate inhibitory effects on UGT1A1.

Objective This study aimed to evaluate whether the onset of the plateau phase of slow hepatitis B surface antigen decline in patients with chronic hepatitis B treated with intermittent interferon therapy is related to the frequency of dendritic cell subsets and expression of the costimulatory molecules CD40,CD80,CD83,and CD86. Method This was a cross-sectional study in which patients were divided into a natural history group(namely NH group),a long-term oral nucleoside analogs treatment group(namely NA group),and a plateau-arriving group(namely P group).The percentage of plasmacytoid dendritic cell and myeloid dendritic cell subsets in peripheral blood lymphocytes and monocytes and the mean fluorescence intensity of their surface costimulatory molecules were detected using a flow cytometer. Results In total,143 patients were enrolled(NH group,n = 49;NA group,n = 47;P group,n = 47).The results demonstrated that CD141/CD1c double negative myeloid dendritic cell(DNmDC)/lymphocytes and monocytes(%)in P group(0.041[0.024,0.069])was significantly lower than that in NH group(0.270[0.135,0.407])and NA group(0.273[0.150,0.443]),and CD86 mean fluorescence intensity of DNmDCs in P group(1832.0[1484.0,2793.0])was significantly lower than that in NH group(4316.0[2958.0,5169.0])and NA group(3299.0[2534.0,4371.0]),Adjusted P all<0.001. Conclusion Reduced DNmDCs and impaired maturation may be associated with the onset of the plateau phase during intermittent interferon therapy in patients with chronic hepatitis B.

Objective To explore characteristics of clinical parameters and cytokines in patients with drug-induced liver injury(DILI)caused by different drugs and their correlation with clinical indicators. Method The study was conducted on patients who were up to Review of Uncertainties in Confidence Assessment for Medical Tests(RUCAM)scoring criteria and clinically diagnosed with DILI.Based on Chinese herbal medicine,cardiovascular drugs,non-steroidal anti-inflammatory drugs(NSAIDs),anti-infective drugs,and other drugs,patients were divided into five groups.Cytokines were measured by Luminex technology.Baseline characteristics of clinical biochemical indicators and cytokines in DILI patients and their correlation were analyzed. Results 73 patients were enrolled.Age among five groups was statistically different(P=0.032).Alanine aminotransferase(ALT)(P=0.033)and aspartate aminotransferase(AST)(P=0.007)in NSAIDs group were higher than those in chinese herbal medicine group.Interleukin-6(IL-6)and tumor necrosis factor alpha(TNF-α)in patients with Chinese herbal medicine(IL-6:P<0.001;TNF-α:P<0.001)and cardiovascular medicine(IL-6:P=0.020;TNF-α:P=0.001)were lower than those in NSAIDs group.There was a positive correlation between ALT(r=0.697,P=0.025),AST(r=0.721,P=0.019),and IL-6 in NSAIDs group. Conclusion Older age may be more prone to DILI.Patients with NSAIDs have more severe liver damage in early stages of DILI,TNF-α and IL-6 may partake the inflammatory process of DILI.

Objective:To construct a new thrombus risk assessment model and evaluate its predictive ability for venous thromboembolism(VTE)in the patients with malignant tumors,and to provide the basis for the early predition of the malignant tumor patients with high risk for VTE.Methods:A total of 128 untreated malignant tumor patients were included,of which 40 were diagnosed with VTE within 2 months of malignant tumor diagnosis and categorized as VTE group.A total of 88 patients who did not develop VTE were categorized as non-VTE group.The clinical risk factors and laboratory indicators of the patients in two groups were compared and analyzed;the types of thrombotic events of the patients were analyzed;the diagnostic values of thrombin-antithrombin-complex(TAT),α2-plasmin inhibitor-plasmin complex(PIC),D-dimer(D-dimer),and fibrin degradation products(FDP)in malignant tumors complicated by VTE were assessed using receiver operating characteristic(ROC)curve analysis;Multivariate Logistic regression analysis was used to analyze the correlations of the clinical risk factors and biomarkers with the malignant tumors complicated with VTE.A new thrombus risk assessment model was constructed,consisting of TAT≥0.70 μg·L-1,poor differentiation,and cardiovascular risk factors.The predictive probability of the model for malignant tumors complicated by VTE was evaluated based on the significance,goodness of fit,calibration curve,and C value of the model.The clinical application value of the new thrombus risk assessment model,COMPASS-CAT risk score(CRS),and Khorana risk score(KRS)in assessing malignant tumor patients complicated by VTE was compared using the C value and decision curve analysis(DCA).Results:The plasma levels of TAT(P＜0.001),PIC(P＜0.001),D-dimer(P＜0.05),and FDP(P＜0.01)of the patients in VTE group were higher than those in non-VTE group.Compared with the patients without cardiovascular risk factors,poor differentiation,and lymphatic metastasis,the malignant tumor patients with cardiovascular risk factors(P＜0.001),poor differentiation(P＜0.001),and lymphatic metastasis(P＜0.05)were more likely to develop VTE.Most VTE events(65％)were isolated deep vein thromboembolism(DVT).The ROC curve analysis showed that the area under the curve(AUC),sensitivity,and specificity of TAT and PIC were higher than those of D-dimer and FDP.TAT≥0.70 μg·L-1(P＜0.05),poor differentiation(P＜0.01),and cardiovascular risk factors(P＜0.01)were the independent risk factors for VTE in the malignant tumor patients.A new thrombus risk assessment model consisting of TAT≥0.70 μg·L-1,poor differentiation,and cardiovascular risk factors was constructed.The new risk assessment model had a high goodness of fit(P=0.805)and good predictive ability during internal validation(x2=75.266,P＜0.001).The ROC curve analysis results showed that the C values for the new thrombus risk prediction model,CRS,and KRS were 0.908,0.676,and 0.541,respectively.The DCA curve analysis results showed that the new thrombus risk assessment model had a higher net benefit rate compared with CRS and KRS.Conclusion:TAT and PIC have greater diagnostic efficiency than D-dimer in the early prediction of the malignant tumor patients with high-risk VTE.For the patients included in this study,the new thrombus risk assessment model,constructed from TAT≥0.70 μg·L-1,poor differentiation,and cardiovascular risk factors,has superior diagnostic efficiency and clinical predictive value compared with CRS and KRS.