Intravital microscopy visualizes innate immune crosstalk and function in tissue microenvironment.

Significant advances have been made in the field of intravital microscopy (IVM) on myeloid cells due to the growing number of validated fluorescent probes and reporter mice. IVM provides a visualization platform to directly observe cell behavior and deepen our understanding of cellular dynamics, heterogeneity, plasticity, and cell-cell communication in native tissue environments. This review outlines the current studies on the dynamic interaction and function of innate immune cells with a focus on those that are studied with IVM and covers the advances in data analysis with emerging artificial intelligence-based algorithms. Finally, the prospects of IVM on innate immune cells are discussed.

The chromatin architectural regulator SND1 mediates metastasis in triple-negative breast cancer by promoting CDH1 gene methylation.

BACKGROUND: SND1 participates in tumorigenesis, tumour invasion and metastasis in different cancers. Previous studies have shown that SND1 can promote the invasion and migration of breast cancer cells. Triple-negative breast cancer (TNBC) is a specific breast cancer subtype with high metastatic potential and poor prognosis. However, the specific roles and mechanisms of SND1 in TNBC metastasis remain unaddressed. METHODS: Immunostaining was used to detect the SND1 expression in tissue samples of 58 TNBC and 10 glioblastomas (GBM) as positive control. The correlation between SND1 expression and patient prognosis was assessed using the Kaplan-Meier estimator. The gene expression was evaluated by qRT-PCR, Western blot and immunofluorescence analyses. Gene Ontology analysis, ChIP, a dual-luciferase reporter assay, EMSA, and 3C analysis were applied to identify SND1-activated target genes. Bisulfite sequencing PCR and MeDIP were used to detect DNA methylation. We also used wound healing, Transwell and orthotopic implantation assays to investigate the function of SND1 in TNBC cell migration and invasion. RESULTS: The data of immunohistochemistry manifested that SND1 is the overexpression in metastasized TNBC and an independent factor for TNBC prognosis. SND1 knockdown inhibited the migration and invasion of TNBC cells. We found that SND1 promotes the metastatic phenotype of TNBC cells by epigenetically altering chromatin conformational interactions, which in turn activates DNMT3A transcription. Then, DNMT3A attenuates CCND1 expression by inducing CCND1 gene methylation, leading to TNBC metastasis. CONCLUSION: SND1 can promote the invasion and migration of TNBC cells by promoting DNMT3A expression and suppressing CDH1 activity. SND1 is a potential biomarker and a promising therapeutic target for TNBC.

E3 ligase TRIM15 facilitates non-small cell lung cancer progression through mediating Keap1-Nrf2 signaling pathway.

BACKGROUND: Recent studies have indicated that some members of the tripartite motif (TRIM) proteins function as important regulators for non-small cell lung cancer (NSCLC), However, the regulatory mechanism underpinning aberrant expression of TRIM in NSCLC remains unclear. Here we report that TRIM15 plays important roles in NSCLC progression through modulating Keap1-Nrf2 signaling pathway. METHODS: TRIM15 expression was evaluated by western blot analysis, tissue microarray-based immunohistochemistry analysis. The interactions between TRIM15 and Keap1 were analyzed by co-immunoprecipitation (Co-IP) and immunofluorescence co-localization assay. The correlation between TRIM15 and Keap1 was measured by Co-IP and ubiquitination analysis in vitro. Gain- and lost-of-function experiments were used to detect TRIM15 promotes proliferation and invasion of NSCLC cells both in vitro and vivo. RESULTS: Here, we revealed that TRIM15 was frequently upregulated in NSCLC samples and associated with poor prognosis. Functionally, TRIM15 knockdown resulted in decreased cancer cell proliferation and metastasis, whereas ectopic TRIM15 expression facilitated tumor cancer cell proliferation and metastasis in vitro and in vivo. Moreover, TRIM15 promoted cell proliferation and metastasis depends on its E3 ubiquitin ligase. Mechanistically, TRIM15 directly targeted Keap1 by ubiquitination and degradation, the principal regulator of Nrf2 degradation, leading to Nrf2 escaping from Keap1-mediated degradation, subsequently promoting antioxidant response and tumor progression. CONCLUSIONS: Therefore, our study characterizes the pivotal roles of TRIM15 promotes NSCLC progression via Nrf2 stability mediated by promoting Keap1 ubiquitination and degradation and could be a valuable prognostic biomarker and a potential therapeutic target in NSCLC. Video Abstract.

Disordered Eating Attitudes Among University Students: The Role of Psychological Distress.

OBJECTIVE: The aim of this study was to explore the relationship between psychological distress and disordered eating attitudes. METHODS: The study design was cross-sectional study. The 12-item General Health Questionnaire (ghq-12) and Eating Attitude Test-26 (eat-26) were used to measure psychological distress and disordered eating attitudes, respectively. The data were analyzed using spss version 20.0 Software (spss Inc, ii, Chicago, il, usa). Description statistics were used for height, weight, bmi), age, eat-26 scores and ghq-12 scores. Pearson's correlation analysis was performed to explore the relationship between the eat-26 scores and the ghq-12 scores. RESULTS: The overall prevalence of disordered eating attitudes was 4.6%. The mean ghq-12 score in subjects with disordered eating attitude was higher than that of the control group (P < .05) in both the male and female groups. CONCLUSION: Our study suggested that psychological distress is associated with disordered eating attitudes. Bmi and gender turned out to not be correlated with disordered eating attitude. The findings of this study revealed that university students who have psychological distress also have a tendency toward disordered eating attitudes.

An TRIM59-CDK6 axis regulates growth and metastasis of lung cancer.

Lung cancer (LC) is a devastating malignancy with no effective treatments, due to its complex genomic profile. Using bioinformatics analysis and immunohistochemical of lung carcinoma tissues, we show that TRIM59 as a critical oncoprotein relating to LC proliferation and metastasis. In this study, high TRIM59 expression was significantly correlated with lymph node metastasis, distant metastasis, and tumour stage. Furthermore, up-regulation of TRIM59 expression correlated with poorer outcomes in LC patients. Mechanistically, TRIM59 play a key role in promoting LC growth and metastasis through regulation of extracellular-signal regulated protein kinase (ERK) signalling pathway and epithelial-to-mesenchymal transition (EMT)-markers, as validated by loss-of-function studies. In-depth bioinformatics analysis showed that there is preliminary evidence of co-expression of TRIM59 and cyclin dependent kinase 6 (CDK6) in LC. Notably, CDK6 expression significantly decreased when TRIM59 was knocked down in the LC cells. In contrast, exogenous up-regulation of TRIM59 expression also induced significant increases in the expression of CDK6. Moreover, the expression of CDK6 was also inhibited by the ERK signalling inhibitor, U0126. The results of both loss- and gain-of-function studies showed that TRIM59 could regulate the expression of CDK6. Collectively, these data provide evidence that TRIM59 is involved in lung carcinoma growth and progression possibly through the induction of CDK6 expression and EMT process by activation of ERK pathway.

MOV10 inhibits replication of porcine reproductive and respiratory syndrome virus by retaining viral nucleocapsid protein in the cytoplasm of Marc-145 cells.

Porcine reproductive and respiratory syndrome virus (PRRSV) has been a major threat to global industrial pig farming ever since its emergence in the late 1980s. Identification of sustainable and effective control measures against PRRSV transmission is a pressing problem. The nucleocapsid (N) protein of PRRSV is specifically localized in the cytoplasm and nucleus of virus-infected cells which is important for PRRSV replication. In the current study, a new host restricted factor, Moloney leukemia virus 10-like protein (MOV10), was identified as an inhibitor of PRRSV replication. N protein levels and viral replication were significantly reduced in Marc-145 cells stably overexpressing MOV10 compared with those in wild-type Marc-145 cells. Adsorption experiments revealed that MOV10 did not affect the attachment and internalization of PRRSV. Co-immunoprecipitation and immunofluorescence co-localization analyses showed that MOV10 interacted and co-localized with the PRRSV N protein in the cytoplasm. Notably, MOV10 affected the distribution of N protein in the cytoplasm and nucleus, leading to the retention of N protein in the former. Taken together, these findings demonstrate for the first time that MOV10 inhibits PRRSV replication by restricting the nuclear import of N protein. These observations have great implications for the development of anti-PRRSV drugs and provide new insight into the role of N protein in PRRSV biology.

Determination of alkaline phosphatase activity and of carcinoembryonic antigen by using a multicolor liquid crystal biosensor based on the controlled growth of silver nanoparticles.

An ultrasensitive liquid crystal biosensor is described for multicolor visualization of the activity of alkaline phosphatase (ALP) based on the controlled growth of silver nanoparticles. The enzymatic product is accumulated on the surface of the LC sensing film by means of silver deposition, and the birefringent signal (observed with a polarizing microscope) is strongly enhanced as a result. The presence of AuNPs also enhances the sensitivity by about 4 orders of magnitude. The bright spots in polarized optical microscopy (POM) images increase with increasing activities of ALP. The signal intensities of the spots are then calculated by using Photoshop software and by multiplying the average brightness of the spots by the pixel value. The detection limit for ALP is 1.2 nU·mL-1, which is 5-7 orders of magnitude lower than other colorimetric or fluorometric methods. The method was applied to a highly sensitive immunoassay for the carcinoembryonic antigen (CEA) by integrating immunomagnetic separation. The immunoassay was applied to the analysis of complex samples without tedious sample pretreatment, and a detection limit as low as 0.35 pg·mL-1 of CEA was achieved. The method has attractive features in that it provides an ultrasensitive multicolor visualization approach for enzymes such as ALP, but also paves the way to a new kind of immunoassay coupled to immunomagnetic separation. Graphical abstract A signal enhanced liquid crystal (LC)-based multicolor immunosensor is described that is based on immunomagnetic separation and biometallization. Alkaline phosphatase (ALP) and carcinoembryonic antigen (CEA) can be easily visualized by bare eyes using the polarized optical microscopy (POM) images of LCs.

Scandium-catalyzed chemoselective carbene insertion into N-H over S-H: access to o-alkylamine-diaryl disulfides.

Herein, we report a scandium-catalyzed chemoselective carbene insertion into a N-H bond over a S-H bond with disulfide formation. This reaction represents the first example of the synthesis of o-alkylamine-diaryl disulfides through the N-alkylation of o-aminobenzenethiol, while also undergoing oxidative coupling to form a S-S bond. Control experiments explain the chemo-selectivity of this rare-earth-metal Lewis acid-induced catalysis by a carbene outer-sphere nucleophilic addition mechanism. This method holds tremendous potential as a valuable tool for functionalizing advanced-synthetic-intermediates, offering numerous applications in medicinal and materials chemistry.

Stiffness sensing via Piezo1 enhances macrophage efferocytosis and promotes the resolution of liver fibrosis.

Tissue stiffening is a predominant feature of fibrotic disorders, but the response of macrophages to changes in tissue stiffness and cellular context in fibrotic diseases remains unclear. Here, we found that the mechanosensitive ion channel Piezo1 was up-regulated in hepatic fibrosis. Macrophages lacking Piezo1 showed sustained inflammation and impaired spontaneous resolution of early liver fibrosis. Further analysis revealed an impairment of clearance of apoptotic cells by macrophages in the fibrotic liver. Macrophages showed enhanced efferocytosis when cultured on rigid substrates but not soft ones, suggesting stiffness-dependent efferocytosis of macrophages required Piezo1 activation. Besides, Piezo1 was involved in the efficient acidification of the engulfed cargo in the phagolysosomes and affected the subsequent expression of anti-inflammation genes after efferocytosis. Pharmacological activation of Piezo1 increased the efferocytosis capacity of macrophages and accelerated the resolution of inflammation and fibrosis. Our study supports the antifibrotic role of Piezo1-mediated mechanical sensation in liver fibrosis, suggesting that targeting PIEZO1 to enhance macrophage efferocytosis could induce fibrosis regression.

Enhanced d-π overlap in a graphene supported Ni/PtNi heterojunction for efficient seawater hydrogen evolution.

d-π overlap, which represents overlap between metal-d and graphene-π orbitals to facilitate electron transfer, has rarely been reported. Ni/PtNi-G2 exhibits exceptional performance in seawater hydrogen evolution due to the electron-rich surface on Pt resulting from enhanced d-π overlap and subsequent electron transfer from graphene and Ni to Pt.

Strain Engineering and Halogen Compensation of Buried Interface in Polycrystalline Halide Perovskites.

Inverted perovskite solar cells based on weakly polarized hole-transporting layers suffer from the problem of polarity mismatch with the perovskite precursor solution, resulting in a nonideal wetting surface. In addition to the bottom-up growth of the polycrystalline halide perovskite, this will inevitably worse the effects of residual strain and heterogeneity at the buried interface on the interfacial carrier transport and localized compositional deficiency. Here, we propose a multifunctional hybrid pre-embedding strategy to improve substrate wettability and address unfavorable strain and heterogeneities. By exposing the buried interface, it was found that the residual strain of the perovskite films was markedly reduced because of the presence of organic polyelectrolyte and imidazolium salt, which not only realized the halogen compensation and the coordination of Pb2+ but also the buried interface morphology and defect recombination that were well regulated. Benefitting from the above advantages, the power conversion efficiency of the targeted inverted devices with a bandgap of 1.62 eV was 21.93% and outstanding intrinsic stability. In addition, this coembedding strategy can be extended to devices with a bandgap of 1.55 eV, and the champion device achieved a power conversion efficiency of 23.74%. In addition, the optimized perovskite solar cells retained 91% of their initial efficiency (960 h) when exposed to an ambient relative humidity of 20%, with a T80 of 680 h under heating aging at 65 °C, exhibiting elevated durability.

Inhibition of mTORC2 improves brain injury in epileptic rats by promoting chaperone-mediated autophagy.

Epilepsy can seriously affect children's cognitive and behavioral development. The mechanistic target of rapamycin(mTOR) pathway plays an important role in neurodevelopment and epilepsy, but the mechanism of mechanistic target of rapamycin complex 2 (mTORC2) in epilepsy is still unclear. Here, we compared the similarities and differences of the mechanisms of action of mechanistic target of rapamycin complex 1 (mTORC1) and mTORC2 complex in the pathogenesis of epilepsy. Our research results show that the levels of apoptosis in cortical and hippocampal neurons were upregulated in epileptic rats (F = 32.15, 30.96; both P < 0.01), and epilepsy caused neuronal damage (F = 8.13, 9.43; both P < 0.01). The mTORC2-Akt pathway was activated in the cortex and hippocampus of epileptic rats. Inhibition of mTORC2 resulted in decreased levels of apoptosis and reduced neuronal damage in the cortex and hippocampus of epileptic rats. In the hippocampus, selective inhibition of mTORC2 increased lysosome-associated membrane protein 2 A (LAMP2A) protein expression compared with the control group, and the difference was statistically significant (F = 3.02, P < 0.05). Finally, we concluded that in the hippocampus, selective inhibition of mTORC2 can improve epileptic brain injury in rats by increasing chaperone-mediated autophagy (CMA) levels.

Full-length genome sequence of porcine epidemic diarrhea virus strain SDTA13-2020.

We report here the complete genome sequence of porcine epidemic diarrhea virus (PEDV) strain SDTA13-2020, isolated from a suckling piglet with watery diarrhea in Shandong, China. The isolate is genetically close to other recent Chinese G2 genotype PEDVs and distinct from the classical PEDVs.

Genome Sequence of Chinese Porcine Parvovirus Strain BJ2.

Porcine parvovirus (PPV) strain BJ2 was isolated from a pig with symptoms consistent with PPV in Beijing, China. The analysis showed that the PPV genome sequence has the characteristics of a German cluster 27a strain and the virulent Kreese strain, which will facilitate understanding of the prevalence of PPV in China.

Association between Sleep Duration and Left Ventricular Hypertrophy for Patients with Type 2 Diabetes Mellitus.

Objective: In this study, we aimed to estimate the impact of sleep duration on left ventricular hypertrophy (LVH) in type 2 diabetes mellitus (T2DM). Methods: Consecutive patients with T2DM undergoing transthoracic echocardiography (TTE) in our center from October 2017 to February 2021 were analyzed. The association of the risk of LVH in T2DM patients was evaluated using univariable and multivariable logistic regression analyses. Results: This study finally included 2689 adult patients (mean age 51.8 ± 12.5 years, 56.2% men, mean sleep duration 7.6 ± 1.4 hours per day). Of all patients, 655 (24.4%) patients were diagnosed with LVH and 2034 did not have LVH. All patients were adults and were diagnosed with T2DM. In the univariate and multivariate regression analyses, gender, sleep duration, body mass index (BMI), waist, hemoglobin (Hb), blood creatinine (Cr), and high-density lipoprotein cholesterol (HDL-c) were associated with LVH. In the restricted cubic spline (RCS) model, the cut-off points of sleep duration given refer to the group of patients with T2DM and LVH were 8 hours per day. With the cut-off points, the multivariable analysis demonstrated that, for diabetic patients, LVH was significantly correlated with a sleep duration of 8 hours per day, hemoglobin, blood urea nitrogen (BUN), and HDL-c. Conclusion: For patients with T2DM, long sleep duration (>8 hours per day), hemoglobin, BUN, and HDL-c were independently associated with LVH. This trial is registered with NCT03811470.

A Prediction Model for Sight-Threatening Diabetic Retinopathy Based on Plasma Adipokines among Patients with Mild Diabetic Retinopathy.

Background: Accumulating evidence has suggested a link between adipokines and diabetic retinopathy (DR). This study is aimed at investigating the risk factors for sight-threatening DR (STDR) and establishing a prognostic model for predicting STDR among a high-risk population of patients with type 2 diabetes mellitus (T2DM). Methods: Plasma concentrations of adipokines were determined by enzyme-linked immunosorbent assay. In the case-control set, principal component analysis (PCA) was performed to select optimal predictive cytokines for STDR, involving severe nonproliferative DR (NPDR) and proliferative DR. Support vector machine (SVM) was used to examine the possible combination of baseline plasma adipokines to discriminate the patients with mild NPDR who will later develop STDR. An individual prospective cohort with a follow-up period of 3 years was used for the external validation. Results: In both training and testing sets, involving 306 patients with T2DM, median levels of plasma adiponectin (APN), leptin, and fatty acid-binding protein 4 (FABP4) were significantly higher in the STDR group than those in mild NPDR. Except for adipsin, the other three adipokines, FABP4, APN, and leptin, were selected by PCA and integrated into SVM. The accuracy of the multivariate SVM classification model was acceptable in both the training set (AUC = 0.81, sensitivity = 71%, and specificity = 91%) and the testing set (AUC = 0.77, sensitivity = 61%, and specificity = 92%). 110 T2DM patients with mild NPDR, the high-risk population of STDR, were enrolled for external validation. Based on the SVM, the risk of each patient was calculated. More STDR occurred in the high-risk group than in the low-risk group, which were grouped by the median value of APN, FABP4, and leptin, respectively. The model was validated in an individual cohort using SVM with the AUC, sensitivity, and specificity reaching 0.77, 64%, and 91%, respectively. Conclusions: Adiponectin, leptin, and FABP4 were demonstrated to be associated with the severity of DR and maybe good predictors for STDR, suggesting that adipokines may play an important role in the pathophysiology of DR development.

E3 ligase TRIM28 promotes anti-PD-1 resistance in non-small cell lung cancer by enhancing the recruitment of myeloid-derived suppressor cells.

BACKGROUND: Alterations in several tripartite motif-containing (TRIM) family proteins have been implicated in the pathogenesis of lung cancer. TRIM28, a member of the TRIM E3 ligase family, has been associated with tumorigenesis, cell proliferation, and inflammation. However, little is known about TRIM28 expression and its role in the immune microenvironment of non-small cell lung cancer (NSCLC). METHODS: We assessed the clinical significance of TRIM28 in tissue microarrays and TCGA cohorts. We investigated the function of TRIM28 in syngeneic mouse tumor models, the KrasLSL-G12D/+; Tp53fl/fl (KP) mouse model, and humanized mice. Immune cell composition was analyzed using flow cytometry and immunohistochemistry. RESULTS: Our findings revealed a positive correlation between TRIM28 expression and the infiltration of suppressive myeloid-derived suppressor cells (MDSCs) in NSCLC. Moreover, silencing TRIM28 enhanced the efficacy of anti-PD-1 immunotherapy by reshaping the inflamed tumor microenvironment. Mechanistically, we demonstrated that TRIM28 could physically interact with receptor-interacting protein kinase 1 (RIPK1) and promote K63-linked ubiquitination of RIPK1, which is crucial for sustaining activation of the NF-κB pathway. Mutagenesis of the E3 ligase domain corroborated the essential role of E3 ligase activity in TRIM28-mediated NF-κB activation. Further experiments revealed that TRIM28 could upregulate the expression of CXCL1 by activating NF-κB signaling. CXCL1 could bind to CXCR2 on MDSCs and promote their migration to the tumor microenvironment. TRIM28 knockdown increased responsiveness to anti-PD-1 therapy in immunocompetent mice, characterized by increased CD8+T tumor-infiltrating lymphocytes and decreased MDSCs. CONCLUSION: The present study identified TRIM28 as a promoter of chemokine-driven recruitment of MDSCs through RIPK1-mediated NF-κB activation, leading to the suppression of infiltrating activated CD8+T cells and the development of anti-PD-1 resistance. Understanding the regulation of MDSC recruitment and function by TRIM28 provides crucial insights into the association between TRIM28 signaling and the development of an immunosuppressive tumor microenvironment. These insights may inform the development of combination therapies to enhance the effectiveness of immune checkpoint blockade therapy in NSCLC.

[A prospective randomized controlled clinical trial of irinotecan plus cisplatin versus gemcitabine plus cisplatin as a first-line treatment for advanced non-small cell lung cancer].

OBJECTIVE: To prospectively evaluate the efficacy and toxicity of irinotecan plus cisplatin (IP regimen) compared with gemcitabine plus cisplatin (GP regimen) as a first-line treatment for advanced non-small cell lung cancer (NSCLC). METHODS: A total of 63 patients were randomly assigned to two regimens. IP Group (31 patients): irinotecan 100 mg/m(2), iv, d1 and d8; cisplatin 25 mg/m(2), iv, d1 to d3, and 3 weeks a cycle. GP Group (32 patients): gemcitabine 1000 mg/m(2), d1 and d8; cisplatin 25 mg/m(2), iv, d1 to d3, and 3 weeks a cycle. All the patients at least received two cycles of therapy. The response rate (RR), disease control rate (DCR), median time to tumor progression (TTP), median survival time (MST), l-year survival rate, and side effects were observed. RESULTS: Among the 31 cases of IP group, 8 patients had PR, 17 patients had SD and 6 patients had PD. The RR and DCR were 25.8% (8/31) and 80.6% (25/31), respectively. The TTP was 6.7 months, MST was 11.2 months and the 1-year survival rate was 45.2% (14/31). Among 32 cases in the GP group, 11 patients had PR, 18 patients had SD and 3 patients had PD. The RR and DCR were 34.4% (11/32) and 90.6% (29/32), respectively. The TTP was 6.5 months, MST was 11.0 months and the 1-year survival rate was 43.7% (14/32). The main side effects of the two groups included hematologic toxicities, digestive tract reaction and hair loss. The incidence of diarrhea in the IP group was significantly higher than that in the GP group (P < 0.05), but the incidence of thrombocytopenia in the GP group was significantly higher than that in the IP group (P < 0.01). CONCLUSIONS: Our findings demonstrate that the two regimens have similar efficacy as a first-line treatment for advanced NSCLC. The major toxicities of the two regimens are well tolerable.

A novel electrochemical immunosensor for dibutyl phthalate based on Au@Pt/PEI-rGO and DNA hybridization chain reaction signal amplification strategy.

Herein, a sensitive immunosensor for the rapid detection of Dibutyl phthalate (DBP) small molecules was developed. Its principle is based on Au@Pt/Polyethyleneimine (PEI)-rGO and hybridization chain reaction signal amplification system. First, Au@Pt/PEI-rGO modified electrode is used as a signal amplification platform and the antibody is fixed. In the presence of target DBP, it competes with DBP-bovine serum albumin-S0 for binding antibody. Finally, the DNA concatemer carrying a large number of signal molecules methylene blue combines with its S0 to produce a reduced electrochemical signal. Under the most reasonable conditions, this immunosensor showed a good linear range from1 pg mL-1 to 0.1 µg mL-1with a low detection limit of 0.276 pg mL-1. It has been verified that this immunosensor has good selectivity, reproducibility and stability. The designed biosensing solution will open up a new path for DBP monitoring and other small molecule targets in the food field.

Catalytic hairpin assembly assisted target-dependent DNAzyme nanosystem coupled with AgPt@Thi for the detection of lead ion.

An ultrasensitive electrochemical biosensor for detection of lead ions (Pb2+) is proposed based on catalytic hairpin assembly and target-induced DNAzyme signal amplification strategy. Polyethyleneimine-reduced graphene oxide (PEI-rGO) combined with gold@silver nanosheets (Au@Ag NSs) are used as electrode substrate modification materials, which not only increase the specific surface area but also exhibit stronger conductivity than pure PEI-rGO or Au@Ag NSs. Hairpin chain 1 (HP1) is immobilized on the surface of modified electrode by Au-S. Then trigger (Tr) DNA can induce the opening of the HP1 hairpin, thus exposing the binding sequence to hybridize with Hairpin chain 2 (HP2) and catalyzing the opening and binding of the hairpin HP2. The process is cyclic and will produce abundant HP1-HP2 duplex strands. When Pb2+ is present, it can catalyze DNAzyme (Pb2+-HP2) to specifically cut the substrate chain HP1, and only a partial sequence of HP1 remains on the surface of the electrode. Finally, the signal probe (AgPt@Thi-CP) can be hybridized with the part of the HP1 sequence after being cut to generate a significant electrical signal. Under optimal conditions, the Pb2+ concentration measured by prepared electrochemical biosensor has a good linear relationship in the range of 0.05 pM-5 nM, and the detection limit is 0.028 pM. This method can be used for the trace detection of Pb2+ in tap water samples, and it also provides a platform for the detection of other targets.