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.

OBJECTIVE To investigate the efficacy and safety of Wuling capsules combined with low-dose quetiapine in the treatment of oldest-old patients with insomnia accompanied by anxiety and depression. METHODS The clinical data of 96 oldest- old patients （aged≥80 years） with insomnia accompanied by anxiety and depression who were attending outpatient clinics or hospitalized in our hospital from June 2020 to December 2022 were retrospectively analyzed. According to the different drug treatments， the patients were divided into Wuling capsules group （0.99 g， tid， 34 cases）， quetiapine group （25-50 mg， qn， 30 cases） and combination group （using Wuling capsules and quetiapine simultaneously， same as the single drug groups， 32 cases）. Before and after 8 weeks of treatment， the patients of three groups were compared in terms of photoplethysmography sleep monitoring indexes （total sleep duration， sleep efficiency， sleep latency， and the number of awakening）， Pittsburgh sleep quality index （PSQI） score， 14-item Hamilton anxiety scale （HAMA-14） score， 17-item Hamilton depression scale （HAMD-17） score， mini-mental state examination （MMSE） score， and serum levels of interleukin-1β （IL-1β） and tumor necrosis factor-α （TNF-α）； the therapeutic effects and adverse drug reactions of the three groups were observed and compared. RESULTS Compared with before treatment， the total sleep time， sleep efficiency and MMSE scores of the three groups were significantly longer or higher after treatment （P＜0.05）， while the sleep latency， number of awakening， PSQI score， HAMA-14 score， HAMD-17 score， serum IL-1β and TNF-α levels were significantly shorter or lower after treatment （P＜0.05）. Sleep latency， number of awakening， HAMA-14 score， HAMD-17 score and serum TNF-α level in quetiapine group were significantly shorter or lower than Wuling capsules group after treatment （P＜0.05）. Moreover， the above indexes in the combination group were significantly better than quetiapine group and Wuling capsules group （P＜0.05）. The total effective rate of treatment in the combination 1731786794@qq.com group was significantly higher than the other two groups （P＜0.05）. There was no significant difference in the incidence of mail：2408797210@qq.com adverse drug reactions among the three groups （P＞0.05）. CONCLUSIONS The therapeutic effect of Wuling capsules combined with low-dose quetiapine is better than that of individual drugs for oldest-old patients with insomnia accompanied with anxiety and depression， not increasing the risk of adverse reactions.

Objective To evaluate the application value of hydrogel in image guided radiotherapy(IGRT)for prostate cancer(PCa).Methods Eighty PCa patients in the First Affiliated Hospital of Hebei North University from October 2022 to February 2023 were collected.The patients were divided into experiment group injected with hydrogel(n=33)and control group without hydrogel(n=47)by central random system allocation.The acute and advanced radiation proctitis(RP)incidence rate of the two groups were compared.Patients in experimental group were divided into RP group(n=5)and non-RP group(n=28).The independent risk factors leading to RP were analyzed by using logistic regression for PCa patients.Results In experiment group,12.1％(4/33)of the patients developed acute grade Ⅰ RP,and 3.0％(1/33)developed advanced grade Ⅰ RP.In control group,31.9％(15/47)of the patients developed acute grade Ⅰ RP,and 12.8％(6/47)developed acute grade Ⅱ RP;19.1％(9/47)of patients developed advanced grade Ⅰ RP,4.3％(2/47)developed advanced grade Ⅱ RP,and 2.1％(1/47)developed advanced grade Ⅲ RP.The incidence of acute and advanced RP in experiment group was lower than that in control group(P<0.05).The application of hydrogel effectively reduced rectal toxicity.Age,rectal volume,V70 and V78 were independent risk factors for the incidence of RP in Pca patients(P<0.05).The characteristics of hydrogel injection were not related to the incidence of RP for Pca patients.Conclusions Hydrogel can effectively reduce the rectal toxicity for Pca patients in IGRT and has little impact on the overall treatment.Hydrogel has certain clinical application and promotion value.

Objective To observe the efficacy and safety of Morinda officinalis oligosaccharides in the continuation treatment of mild and moderate depression.Methods An open,single-arm,multi-center design was adopted in our study.Adult patients with mild and moderate depression who had received acute treatment of Morinda officinalis oligosaccharides were enrolled and continue to receive Morinda officinalis oligosaccharides capsules for 24 weeks,the dose remained unchanged during continuation treatment.The remission rate,recurrence rate,recurrence time,and the change from baseline to endpoint of Hamilton Depression Scale(HAMD),Hamilton Anxiety Scale(HAMA),Clinical Global Impression-Severity(CGI-S)and Arizona Sexual Experience Scale(ASEX)were evaluated.The incidence of treatment-related adverse events was reported.Results The scores of HAMD-17 at baseline and after treatment were 6.60±1.87 and 5.85±4.18,scores of HAMA were 6.36±3.02 and 4.93±3.09,scores of CGI-S were 1.49±0.56 and 1.29±0.81,scores of ASEX were 15.92±4.72 and 15.57±5.26,with significant difference(P＜0.05).After continuation treatment,the remission rate was 54.59％(202 cases/370 cases),and the recurrence rate was 6.49％(24 cases/370 cases),the recurrence time was(64.67±42.47)days.The incidence of treatment-related adverse events was 15.35％(64 cases/417 cases).Conclusion Morinda officinalis oligosaccharides capsules can be effectively used for the continuation treatment of mild and moderate depression,and are well tolerated and safe.

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.

Viral myocarditis(VMC)is one of the most common acquired heart diseases in children and teenagers.However,its pathogenesis is still unclear,and effective treatments are lacking.This study aimed to investigate the regulatory pathway by which exosomes alleviate ferroptosis in cardiomyocytes(CMCs)induced by coxsackievirus B3(CVB3).CVB3 was utilized for inducing the VMC mouse model and cellular model.Cardiac echocardiography,left ventricular ejection fraction(LVEF),and left ventricular fractional shortening(LVFS)were implemented to assess the cardiac function.In CVB3-induced VMC mice,cardiac insufficiency was observed,as well as the altered levels of ferroptosis-related indicators(glutathione peroxidase 4(GPX4),glutathione(GSH),and malondialdehyde(MDA)).However,exosomes derived from human umbilical cord mesenchymal stem cells(hucMSCs-exo)could restore the changes caused by CVB3 stimulation.Let-7a-5p was enriched in hucMSCs-exo,and the inhibitory effect of hucMSCs-exolet-7a-5p mimic on CVB3-induced ferroptosis was higher than that of hucMSCs-exomimicNC(NC:negative control).Mothers against decapentaplegic homolog 2(SMAD2)increased in the VMC group,while the expression of zinc-finger protein 36(ZFP36)decreased.Let-7a-5p was confirmed to interact with SMAD2 messenger RNA(mRNA),and the SMAD2 protein interacted directly with the ZFP36 protein.Silencing SMAD2 and overexpressing ZFP36 inhibited the expression of ferroptosis-related indicators.Meanwhile,the levels of GPX4,solute carrier family 7,member 11(SLC7A11),and GSH were lower in the SMAD2 overexpression plasmid(oe-SMAD2)+let-7a-5p mimic group than in the oe-NC+let-7a-5p mimic group,while those of MDA,reactive oxygen species(ROS),and Fe2+increased.In conclusion,these data showed that ferroptosis could be regulated by mediating SMAD2 expression.Exo-let-7a-5p derived from hucMSCs could mediate SMAD2 to promote the expression of ZFP36,which further inhibited the ferroptosis of CMCs to alleviate CVB3-induced VMC.