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.

AIM To investigate the protective effects and the mechanism of corosolic acid on doxorubicin-induced cardiotoxicity in H9c2 cardiomyocytes.METHODS To screen and determine the effective concentration of corosolic acid,the injury models of H9c2 cardiomyocytes established by 1 μmol/L doxorubicin were exposed to 24 h different concentrations of corosolic acid,followed by detections of their cell activity by MTT method;their cell apoptosis morphology by Hoechst 33342 staining method;their cell apoptosis rate by Annexin V-FITC/PI double staining method;their intracellular ROS level by DCFH-DA probe;their intracellular iron level by iron ion colorimetry;and their protein expressions of Bax,Bcl-2,cleaved-caspase3,Nrf2,GPX4 and Ptgs2 by Western blot.RESULTS Upon the doxorubicin-induced injury models of H9c2 cardiomyocytes,corosolic acid improved their viability and survival rate(P<0.05),decreased their levels of ROS and Fe2+ and the apoptosis rate(P<0.05),up-regulated the protein expressions of Bcl-2,Nrf2 and GPX4(P<0.05),and down-regulated the protein expressions of Bax,cleved-caspase 3 and Ptgs2(P<0.05).CONCLUSION Corosolic acid can inhibit the ROS level and apoptosis of doxorubicin-induced injury models of H9c2 cardiomyocytes,and the iron death as well via activating Nrf2/GPX4 pathway.

Objective:To investigate the clinical features and prognosis of male with anti-melanoma differentiation-associated gene 5 (MDA5) autoantibody.Methods:The clinical data of 246 patients with DM and anti-MDA5 autoantibodies hospitalized by Jiangsu Myositis Cooperation Group from 2017 to 2020 were collected and retrospectively analyzed. Chi-square test was performed to compared between counting data groups; Quantitative data were expressed by M ( Q1, Q3), and rank sum test was used for comparison between groups; Single factor survival analysis was performed by Kaplan-Meier method and Log rank test; Cox regression analysis were used for multivariate survival analysis. Results:①The male group had a higher proportion of rash at the sun exposure area [67.1%(47/70) vs 52.8%(93/176), χ2=4.18, P=0.041] and V-sign [50.0%(35/70) vs 30.7%(54/176), χ2=8.09, P=0.004] than the female group. The male group had higher levels of creatine kinase [112(18, 981)U/L vs 57 (13.6, 1 433)U/L, Z=-3.50, P<0.001] and ferritin [1 500 (166, 32 716)ng/ml vs 569 (18, 14 839)ng/ml, Z=-5.85, P<0.001] than the female group. The proportion of ILD [40.0%(28/70) vs 59.7%(105/176), χ2=7.82, P=0.020] patients and the red blood cell sedimentation rate[31.0(4.0, 101.5)mm/1 h vs 43.4(5.0, 126.5)mm/1 h, Z=-2.22, P=0.026] in the male group was lower than that of the female group, but the proportion of rapidly progressive interstitial lung disease (PR-ILD) [47.1%(33/70) vs 31.3%(55/176), χ2=5.51, P=0.019] was higher than that of the female group. ②In male patients with positive anti-MDA5 antibodies,the death group had a shorter course of disease[1.0(1.0, 3.0) month vs 2.5(0.5,84) month, Z=-3.07, P=0.002], the incidence of arthritis [16.7%(4/24) vs 42.2%(19/45), χ2=4.60, P=0.032] were low than those in survival group,while aspartate aminotransferase (AST)[64(22.1, 565)U/L vs 51(14,601)U/L, Z=-2.42, P=0.016], lactate dehydrogenase (LDH) [485(24,1 464)U/L vs 352(170, 1 213)U/L, Z=-3.38, P=0.001], C-reactive protein (CRP) [11.6(2.9, 61.7) mg/L vs 4.95(0.6, 86.4) mg/L, Z=-1.96, P=0.050], and ferritin levels [2 000(681, 7 676) vs 1 125 (166, 32 716)ng/ml, Z=-3.18, P=0.001] were higher than those in the survival group, and RP-ILD [95.8%(23/24) vs 22.2%(10/45), χ2=33.99, P<0.001] occurred at a significantly higher rate. ③Cox regression analysis indicated that the course of disease LDH level, and RP-ILD were related factors for the prognosis of male anti-MDA5 antibodies [ HR (95% CI)=0.203(0.077, 0.534), P=0.001; HR (95% CI)=1.002(1.001, 1.004), P=0.003; HR (95% CI)=95.674 (10.872, 841.904), P<0.001]. Conclusion:The clinical manifestations of male anti-MDA5 antibody-positive patients are different from those of female. The incidence of ILD is low, but the proportion of PR-ILD is high. The course of disease, serum LDH level, and RP-ILD are prognostic factors of male anti-MDA5 antibody-positive patients.

Objective To investigate the mechanism of miR-135a/MYC-mediated resistance to venaclar treatment in myelodysplastic syndromes(MDS)with acute myeloid leukaemia(AML).Methods Eighty-six cases of patients were selected,including 23 healthy donors(control group),47 MDS patients with vinecella resistance(MDS group),and 16 AML patients with vinecella resistance transformed from myelodysplastic syndrome(AML group).The expression levels of miR-135a and MYC in the tissues of the three groups were detected.THP1 cells were divided into miR-NC group(transfected with nonsense sequence)and miR-135a minics group(transfected with miR-135a minics),and the cells were treated with venaclar concentration of 0,0.01,1,and 100 μmol·L-1 for 24 hours,and then detected the cell viability and apoptosis rate in each group.Results The expression of MYC mRNA were 1.00±0.14,0.21±0.04,and 0.25±0.08 in patients of the NC,MDS,and AML groups,respectively;the protein expression of MYC were 1.00±0.15,1.31±0.12 and 1.49±0.16,respectively(P＜0.05).At the cellular level,miR-135a expression were 1.00±0.11,1.31±0.15 and 1.93±0.23 in the BMSCs,MUTZ-1 and THP1 groups;MYC protein expression were 1.00±0.15,1.57±0.22 and 1.97±0.31,the differences were significant(P＜0.05).The methods showed the cell viability of miR-NC group were(100.00±13.26)％,(92.33±10.28)％,(85.41±11.37)％and(28.24±6.02)％at 0,0.01,1,100 μmol·L-1venaclar drug concentration,respectively;cell viability of miR-135a mimics group were(105.12±12.35)％,(82.11±12.07)％,(46.13±8.06)％and(18.20±5.03)％,respectively,there was statistical difference between the two groups only in the 1 μmol·L-1 venaclar drug concentration(P＜0.05).The methods showed that the apoptosis rates in miR-NC group at 0,0.01,1,100 μmol·L-1 venaclar drug concentration were(100.00±11.45)％,(92.48±12.04)％,(108.72±9.63)％and(207.15±21.49)％,the apoptosis rates in miR-135a mimics group were(106.34±16.21)％,(117.26±10.13)％,(269.41±23.59)％and(184.33±19.28)％,respectively;there was statistical difference between the two groups only in 1 μmol·L-1 venaclar drug concentration(P＜0.05).Conclusion The results of this study reveal that miR-135a/MYC mediates the mechanism of resistance to venaclar in the treatment of MDS and AML.

Objective To observe the clinical value of recombinant human erythropoietin injection in the treatment of anemia after chemotherapy in leukemia patients,and to explore the difference of efficacy of different doses.Methods Patients with anemia complicated by leukemia chemotherapy were selected as the study objects and randomly divided into control group,low-dose group and high-dose group.Patients in the control group received conventional treatment(oral ferrous succinate combined with dietary conditioning),and patients in the low-dose group were given 75 U·kg-1 recombinant human erythrophorin treatment on the basis of the control group,subcutaneous injection 3 times a week.High-dose group was treated with 150 U·kg-1 recombinant human erythropoietin on the basis of control group,subcutaneous injection 3 times a week.All three groups were treated for 4 weeks.The clinical efficacy,the anemia-related indexes,the expression of mitogen-activated protein kinase path-related proteins in bone marrow stromal cells,Karnofsky performance status(KPS)score and safety of the three groups were compared.Result Control group,low-dose group and high-dose group were enrolled in 32,33 and 33 cases,respectively,without shedding patients.After treatment,the total effective rate of control group,low-dose group and high-dose group were 62.50％(20 cases/32 cases),78.79％(26 cases/33 cases)and 87.88％(29 cases/33 cases),respectively.There was statistical significance in the total effective rate of control group and high-dose group(P＜0.05).After treatment,the hemoglobin levels of control group,low-dose group and high-dose group were(108.76±6.82),(112.43±7.31)and(116.27±7.72)g·L-1,respectively;red blood cell counts were(3.08±0.42)× 1012,(3.34±0.39)× 1012 and(3.58±0.45)× 1012·L-1,respectively;hematocrit were 0.28±0.05,0.31±0.06 and 0.35±0.07,respectively;the relative expression levels of phosphorylated extracellular regulatory protein kinase 1/2 were 1.12±0.16,1.23±0.17 and 1.35±0.22,respectively;the relative expression levels of phosphorylated stress-activated protein kinase were 0.83±0.13,0.76±0.11 and 0.69±0.09,respectively;the expression levels of p-P38 were 0.92±0.10,0.86±0.09 and 0.80±0.09,respectively;the KPS scores were(69.35±6.43),(72.84±6.62)and(76.35±6.77)points,respectively.The above indexes in the low-dose group and the high-dose group were compared with the control group,respectively,and the above indexes in the high-dose group were compared with the low-dose group,and the differences were statistically significant(all P＜0.05).The adverse drug reactions in the three groups were mainly skin allergy and gastrointestinal reactions.The total incidences of adverse drug reactions in the control group,low-dose group and high-dose group was 12.50％,18.18％and 18.18％,respectively,with no statistical significance(all P＞0.05).Conclusion Recombinant human erythropoietin can significantly correct chemotherapy related anemia in leukemia,and improve health status,and the curative effect of 150 U·kg-1 was better than 75 U·kg-1.

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.

AIM: To investigate the efficacy and safety of ZKY001 eye drops with different concentrations in the treatment of corneal epithelial defects(CED)after primary pterygium excision.METHODS: This was a multicenter, randomized, double-blinded, placebo-controlled phase II clinical trial. From March 15, 2022 to November 14, 2022, patients with primary pterygium who had undergone surgery were recruited from 12 tertiary hospitals across China. Using block randomization, 178 patients(178 eyes)were randomly assigned to 3 groups in a 1:1:1 ratio: 0.002% ZKY001 group(n=59), 0.004% ZKY001 group(n=59), and placebo group(n=60, receiving ZKY001 sham eye drops). Subjects in each group received 1 drop of the study drug 4 times per day for 4 d. The percentage of CED area recovery from baseline, the first complete healing time of CED area, the number of first complete healing cases of CED, and changes in visual analogue scale(VAS)scores for eye discomfort including eye pain, foreign body sensation, tearing and photophobia were observed.RESULTS: In terms of improvement in CED, there were no statistically significant differences among the three groups including the first healing time of CED, the percentage improvement in CED area compared to baseline, and the percentage of first healing cases at different follow-up visits(all P>0.05). Numerically, the first healing time of CED was shorter in the test groups compared to the placebo group(67.87±21.688 h for the 0.002% ZKY001 group, 61.48±22.091 h for the 0.004% ZKY001 group, and 68.85±20.851 h for the placebo group). On D1 morning, the percentage improvement in CED area compared to baseline was maximally different from the placebo group, and the numerical difference advantage was maintained at subsequent follow-up visits. The number of first healing cases in the CED area at different follow-up visits was higher in the test groups than the placebo group. In terms of improvement in ocular discomfort, the total VAS scores were lower in the test groups compared to the placebo group, mainly due to reductions in foreign body sensation and pain scores. At D3, the 0.004% ZKY001 group showed statistically significant improvement in foreign body sensation(P<0.017). In terms of safety, the overall incidence of adverse events was low(9.0%)and similar among groups.CONCLUSION: The use of ZKY001 eyedrops after primary pterygium surgery can safely improve the CED repair, and alleviate postoperative symptoms caused by CED.

In recent years, artificial intelligence (AI) technology has advanced rapidly and has been widely applied in various fields such as medicine and pharmacy, accelerating the drug development process. Focusing on the application of AI in the discovery and optimization of lead compounds, this review provides a detailed introduction to AI-assisted virtual screening and molecular generation methods for discovering lead compounds, while particularly highlighting the cases of AI-drived drugs into clinical trials. Additionally, we briefly outline the application of AI basic algorithm models in quantitative structure-activity relationship (QSAR) and drug repurposing, offering insights for AI-based drug discovery.

Objective To evaluate the degree of brain atrophy in spinocerebellar ataxia type 3(SCA3)patients based on artificial intelligence(AI)technology,and to explore the correlation between the degree of brain atrophy and the severity of the disease.Methods The clinical and imaging data of 23 SCA3 patients(SCA3 group)and 24 healthy controls(HC)(HC group)were collected.The International Cooperative Ataxia Rating Scale(ICARS)was used to evaluate the severity of ataxia in patients with SCA3.AI technology was used to process the 3D-T1 WI MR image data of the SCA3 and HC groups to segment and measure the volume and volume percentage of brain,followed by correlation analyses between brain structural alterations and the severity of ataxia in SCA3 patients.Results There were no significant differences in gender and age between the two groups(P＞0.05).The SCA3 group had a significant reduction in the volume and volume percentage of various brain regions,such as the frontal,temporal,parietal,occipital,limbic,right cerebral white mat-ter,subcortical gray matter,cerebellum and brainstem,compared to the HC group(multiple hypothesis testing adjusted P＜0.01).In the SCA3 group,the ICARS showed positive correlation with patient age(r=0.571,P=0.004)and negative correlation with the vol-ume of the left cerebellar white matter,vermis,medulla oblongata,and the volume percentages of bilateral cerebellar white matter,vermis,pons,medulla oblongata(P＜0.05).Conclusion The significant atrophy of the supratentorial and subtentorial regions of the brain in SCA3 patients.The globus pallidus exhibits the most substantial atrophy,suggesting its potential as an imaging diagnostic marker of SC A3.