The feedback loop between MTA1 and MTA3/TRIM21 modulates stemness of breast cancer in response to estrogen.

The metastasis-associated protein (MTA) family plays a crucial role in the development of breast cancer, a common malignancy with a high incidence rate among women. However, the mechanism by which each member of the MTA family contributes to breast cancer progression is poorly understood. In this study, we aimed to investigate the roles of MTA1, MTA3, and tripartite motif-containing 21 (TRIM21) in the proliferation, invasion, epithelial-mesenchymal transition (EMT), and stem cell-like properties of breast cancer cells in vivo and in vitro. The molecular mechanisms of the feedback loop between MTA1 and MTA3/TRIM21 regulated by estrogen were explored using Chromatin immunoprecipitation (ChIP), luciferase reporter, immunoprecipitation (IP), and ubiquitination assays. These findings demonstrated that MTA1 acts as a driver to promote the progression of breast cancer by repressing the transcription of tumor suppressor genes, including TRIM21 and MTA3. Conversely, MTA3 inhibited MTA1 transcription and TRIM21 regulated MTA1 protein stability in breast cancer. Estrogen disrupted the balance between MTA1 and MTA3, as well as between MTA1 and TRIM21, thereby affecting stemness and the EMT processes in breast cancer. These findings suggest that MTA1 plays a vital role in stem cell fate and the hierarchical regulatory network of EMT through negative feedback loops with MTA3 or TRIM21 in response to estrogen, supporting MTA1, MTA3, and TRIM21 as potential prognostic biomarkers and MTA1 as a treatment target for future breast cancer therapies.

CDKL3 is a targetable regulator of cell cycle progression in cancers.

Cell cycle regulation is largely abnormal in cancers. Molecular understanding and therapeutic targeting of the aberrant cell cycle are essential. Here, we identified that an underappreciated serine/threonine kinase, cyclin-dependent kinase-like 3 (CDKL3), crucially drives rapid cell cycle progression and cell growth in cancers. With regard to mechanism, CDKL3 localizes in the nucleus and associates with specific cyclin to directly phosphorylate retinoblastoma (Rb) for quiescence exit. In parallel, CDKL3 prevents the ubiquitin-proteasomal degradation of cyclin-dependent kinase 4 (CDK4) by direct phosphorylation on T172 to sustain G1 phase advancement. The crucial function of CDKL3 in cancers was demonstrated both in vitro and in vivo. We also designed, synthesized, and characterized a first-in-class CDKL3-specific inhibitor, HZ1. HZ1 exhibits greater potency than CDK4/6 inhibitor in pan-cancer treatment by causing cell cycle arrest and overcomes acquired resistance to CDK4/6 inhibitor. In particular, CDKL3 has significant clinical relevance in colon cancer, and the effectiveness of HZ1 was demonstrated by murine and patient-derived cancer models. Collectively, this work presents an integrated paradigm of cancer cell cycle regulation and suggests CDKL3 targeting as a feasible approach in cancer treatment.

Identify the seasonal differences in water quality and pollution sources between river-connected and gate-controlled lakes in the Yangtze River basin.

The river-connected Dongting Lake (DT) and Poyang Lake (PY), and the gate-controlled Taihu Lake (TH) and Chaohu Lake (CH) are the four important lakes in the Yangtze River Basin. The comprehensive Water Quality Index (WQI), the Eutrophication Integrated Index (TLI(Σ)), and the Positive Matrix Factorization (PMF) model were employed to evaluate water quality and the contribution of pollution sources for these lakes. The results show that WQI for all lakes indicated generally good water quality, with DT scoring 73.52-86.18, the highest among them. During the wet season, the eutrophication degree of river-connected lake was medium, and that of gate-controlled lakes was high. The surface runoff and agricultural non-point sources are the main pollution sources for both types of lakes, but their impact is more pronounced in gate-controlled lakes during the wet season. The study provides evidence support for scientific understanding of water quality problems and management strategies in these areas.

Rising Perfluorocyclobutane (PFC-318, c-C4F8) Emissions in China from 2011 to 2020 Inferred from Atmospheric Observations.

Global atmospheric emissions of perfluorocyclobutane (c-C4F8, PFC-318), a potent greenhouse gas, have increased rapidly in recent years. Combining atmospheric observations made at nine Chinese sites with a Lagrangian dispersion model-based Bayesian inversion technique, we show that PFC-318 emissions in China grew by approximately 70% from 2011 to 2020, rising from 0.65 (0.54-0.72) Gg year-1 in 2011 to 1.12 (1.05-1.19) Gg year-1 in 2020. The PFC-318 emission increase from China played a substantial role in the overall increase in global emissions during the study period, contributing 58% to the global total emission increase. This growth predominantly originated in eastern China. The regions with high emissions of PFC-318 in China overlap with areas densely populated with polytetrafluoroethylene (PTFE) factories, implying that fluoropolymer factories are important sources of PFC-318 emissions in China. Our investigation reveals an emission factor of approximately 3.02 g of byproduct PFC-318 emissions per kg of hydrochlorofluorocarbon-22 (HCFC-22) feedstock use in the production of tetrafluoroethylene (TFE) (for PTFE production) and hexafluoropropylene (HFP) if we assume all HCFC-22 produced for feedstock uses in China are pyrolyzed to produce PTFE and HFP. Further facility-level sampling and analysis are needed for a more precise evaluation of emissions from these factories.

The Pre- and Post-column Derivatization on Monosaccharide Composition Analysis, a Review.

Polysaccharides, as common metabolic products in organisms, play a crucial role in the growth and development of living organisms. For humans, polysaccharides represent a class of compounds with diverse applications, particularly in the medical field. Therefore, the exploration of the monosaccharide composition and structural characteristics of polysaccharides holds significant importance in understanding their biological functions. This review provides a comprehensive overview of extraction methods and hydrolysis strategies for polysaccharides. It systematically analyzes strategies and technologies for determining polysaccharide composition and discusses common derivatization reagents employed in further polysaccharide studies. Derivatization is considered a fundamental strategy for determining monosaccharides, as it not only enhances the detectability of analytes but also increases detection sensitivity, especially in liquid chromatography (LC), capillary electrophoresis (CE), and gas chromatography (GC) techniques. The review meticulously examines pre-column and post-column derivatization techniques for monosaccharide analysis, categorizing them based on diverse detection methodologies. It delves into the principles and distinctive features of various derivatization reagents, offering a comparative analysis of their strengths and limitations. Ultimately, the aim is to provide guidance for selecting the most suitable derivatization approach, taking into account the structural nuances, biological functions, and reaction dynamics of polysaccharides.

The Effect of Visual Articulatory Cues on the Identification of Mandarin Tones by Children With Cochlear Implants.

PURPOSE: This study explored the facilitatory effect of visual articulatory cues on the identification of Mandarin lexical tones by children with cochlear implants (CIs) in both quiet and noisy environments. It also explored whether early implantation is associated with better use of visual cues in tonal identification. METHOD: Participants included 106 children with CIs and 100 normal-hearing (NH) controls. A tonal identification task was employed using a two-alternative forced-choice picture-pointing paradigm. Participants' tonal identification accuracies were compared between audio-only (AO) and audiovisual (AV) modalities. Correlations between implantation ages and visual benefits (accuracy differences between AO and AV modalities) were also examined. RESULTS: Children with CIs demonstrated an improved identification accuracy from AO to AV modalities in the noisy environment. Additionally, earlier implantation was significantly correlated with a greater visual benefit in noise. CONCLUSIONS: These findings indicated that children with CIs benefited from visual cues on tonal identification in noise, and early implantation enhanced the visual benefit. These results thus have practical implications on tonal perception interventions for Mandarin-speaking children with CIs.

The impact of vedolizumab therapy on extraintestinal manifestations in patients with inflammatory bowel disease: A systematic review and meta-analysis.

BACKGROUND AND AIM: Extraintestinal manifestations (EIMs) pose a significant threat in inflammatory bowel disease (IBD) patients. Vedolizumab (VDZ) primarily affects the gastrointestinal tract. However, its impact on EIMs remains uncertain. Therefore, we conducted this meta-analysis to examine the effects of VDZ on EIMs during treatment. METHODS: Relevant studies were identified by conducting thorough searches across electronic databases, including PubMed, Ovid Embase, Medline, and Cochrane CENTRAL. Primary outcomes focused on the proportion of patients with resolution for pre-existing EIMs in IBD patients receiving VDZ. Secondary outcomes included the proportion of patients with EIM exacerbations and new onset EIMs during VDZ treatment. RESULTS: Our meta-analysis encompassed 21 studies. The proportion of patients with resolution of pre-existing EIMs in VDZ-treated IBD patients was 39% (150/386; 95% confidence interval [CI] 0.31-0.48). The proportion of patients with EIM exacerbations occurred at a rate of 28% (113/376; 95% CI 0.05-0.50), while new onset EIMs had a rate of 15% (397/2541; 95% CI 0.10-0.20). Subgroup analysis revealed a 40% (136/337) proportion of patients with resolution for articular-related EIMs and a 50% (9/18) rate for erythema nodosum. Exacerbation rates for arthritis/arthralgia, erythema nodosum/pyoderma gangrenosum, and aphthous stomatitis during VDZ use were 28% (102/328), 18% (7/38), and 11% (3/28), respectively. The incidence rate of newly developed EIMs during treatment was 11% (564/4839) for articular-related EIMs, with other EIMs below 2%. CONCLUSION: VDZ demonstrates efficacy in skin-related EIMs like erythema nodosum and joint-related EIMs including arthritis, arthralgia, spondyloarthritis, and peripheral joint diseases. Some joint and skin-related EIMs may experience exacerbation during VDZ therapy.

Highly Ordered Gyroid Nanostructured Polymers: Facile Fabrication by Polymerizable Pluronic Surfactants.

Highly ordered, network-nanostructured polymers offer compelling geometric features and application potential. However, their practical utilization is hampered by the restricted accessibility. Here, we address this challenge using commercial Pluronic surfactants with a straightforward modification of tethering polymerizable groups. By leveraging lyotropic self-assembly, we achieve facile production of double-gyroid mesophases, which are subsequently solidified via photoinduced cross-linking. The exceptionally ordered periodicities of Ia3d symmetry in the photocured polymers are unambiguously confirmed by synchrotron small-angle X-ray scattering (SAXS), which can capture single-crystal-like diffraction patterns. Electron density maps reconstructed from SAXS data complemented by transmission electron microscopy analysis further elucidate the real-space gyroid assemblies. Intriguingly, by tuning the cross-linking through thiol-acrylate chemistry, the mechanical properties of the polymer are modulated without compromising the integrity of Ia3d assemblies. The 3-D percolating gyroid nanochannels demonstrate an ionic conductivity that surpasses that of disordered structures, offering promising prospects for scalable fabrication.

Antimicrobial spiroketal macrolides and dichloro-diketopiperazine from Micromonospora sp. FIMYZ51.

Four compounds (1-4) featuring with an L-rhodinose and spiroketal, possess uncommon continuous hydroxy groups in the macrolide skeleton, and a dichloro-diketopiperazine (5) were isolated from a marine derived Micromonospora sp. FIMYZ51. The determination of the relative and absolute configurations of all isolates was achieved by extensive spectroscopic analyses, single-crystal X-ray diffraction analysis, and ECD calculations. According to structural characteristic and genomic sequences, a plausible biosynthetic pathway for compound 1-4 was proposed and a spirocyclase was inferred to be responsible for the formation of the rare spirocyclic moiety. Compounds 1-4 exhibited potent antifungal activities which is equal to itraconazole against Aspergillus niger. Compounds 1-5 exhibited different degree of inhibitory activities against opportunistic pathogenic bacteria of endocarditis (Micrococcus luteus) with MIC values ranging from 0.0625 µg/mL to 32 µg/mL. Compounds 2 and 3 showed moderate cytotoxicity against drug-resistant tumor cell lines (Namalwa and U266). The result not only provides active lead-compounds, but also reveal the potential of the spirocyclase gene resources from Micromonospora sp., which highlights the promising potential of the strain for biomedical applications.

Pharmacogenomic profiling of intra-tumor heterogeneity using a large organoid biobank of liver cancer.

Inter- and intra-tumor heterogeneity is a major hurdle in primary liver cancer (PLC) precision therapy. Here, we establish a PLC biobank, consisting of 399 tumor organoids derived from 144 patients, which recapitulates histopathology and genomic landscape of parental tumors, and is reliable for drug sensitivity screening, as evidenced by both in vivo models and patient response. Integrative analysis dissects PLC heterogeneity, regarding genomic/transcriptomic characteristics and sensitivity to seven clinically relevant drugs, as well as clinical associations. Pharmacogenomic analysis identifies and validates multi-gene expression signatures predicting drug response for better patient stratification. Furthermore, we reveal c-Jun as a major mediator of lenvatinib resistance through JNK and ß-catenin signaling. A compound (PKUF-01) comprising moieties of lenvatinib and veratramine (c-Jun inhibitor) is synthesized and screened, exhibiting a marked synergistic effect. Together, our study characterizes the landscape of PLC heterogeneity, develops predictive biomarker panels, and identifies a lenvatinib-resistant mechanism for combination therapy.

Effect of High Energy Low Protein Diet on Lipid Metabolism and Inflammation in the Liver and Abdominal Adipose Tissue of Laying Hens.

The aim of this study was to evaluate the effects of a high-energy low-protein (HELP) diet on lipid metabolism and inflammation in the liver and abdominal adipose tissue (AAT) of laying hens. A total of 200 Roman laying hens (120 days old) were randomly divided into two experimental groups: negative control group (NC group) and HELP group, with 100 hens per group. The chickens in the NC group were fed with a basic diet, whereas those in the HELP group were given a HELP diet. Blood, liver, and AAT samples were collected from 20 chickens per group at each experimental time point (30, 60, and 90 d). The morphological and histological changes in the liver and AAT were observed, and the level of serum biochemical indicators and the relative expression abundance of key related genes were determined. The results showed that on day 90, the chickens in the HELP group developed hepatic steatosis and inflammation. However, the diameter of the adipocytes of AAT in the HELP group was significantly larger than that of the NC group. Furthermore, the results showed that the extension of the feeding time significantly increased the lipid contents, lipid deposition, inflammatory parameters, and peroxide levels in the HELP group compared with the NC group, whereas the antioxidant parameters decreased significantly. The mRNA expression levels of genes related to lipid synthesis such as fatty acid synthase (FASN), stearoyl-coA desaturase (SCD), fatty acid binding protein 4 (FABP4), and peroxisome proliferator-activated receptor gamma (PPARγ) increased significantly in the liver and AAT of the HELP group, whereas genes related to lipid catabolism decreased significantly in the liver. In addition, the expression of genes related to lipid transport and adipokine synthesis decreased significantly in the AAT, whereas in the HELP group, the expression levels of pro-inflammatory parameters such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1ß) increased significantly in the liver and AAT. Conversely, the expression level of the anti-inflammatory parameter interleukin-10 (IL-10) decreased significantly in the liver. The results indicated that the HELP diet induced lipid peroxidation and inflammation in the liver and AAT of the laying hens. Hence, these results suggest that chicken AAT may be involved in the development of fatty liver.

Identification of different myofiber types in pigs muscles and construction of regulatory networks.

BACKGROUND: Skeletal muscle is composed of muscle fibers with different physiological characteristics, which plays an important role in regulating skeletal muscle metabolism, movement and body homeostasis. The type of skeletal muscle fiber directly affects meat quality. However, the transcriptome and gene interactions between different types of muscle fibers are not well understood. RESULTS: In this paper, we selected 180-days-old Large White pigs and found that longissimus dorsi (LD) muscle was dominated by fast-fermenting myofibrils and soleus (SOL) muscle was dominated by slow-oxidizing myofibrils by frozen sections and related mRNA and protein assays. Here, we selected LD muscle and SOL muscle for transcriptomic sequencing, and identified 312 differentially expressed mRNA (DEmRs), 30 differentially expressed miRNA (DEmiRs), 183 differentially expressed lncRNA (DElRs), and 3417 differentially expressed circRNA (DEcRs). The ceRNA network included ssc-miR-378, ssc-miR-378b-3p, ssc-miR-24-3p, XR_308817, XR_308823, SMIM8, MAVS and FOS as multiple core nodes that play important roles in muscle development. Moreover, we found that different members of the miR-10 family expressed differently in oxidized and glycolytic muscle fibers, among which miR-10a-5p was highly expressed in glycolytic muscle fibers (LD) and could target MYBPH gene mRNA. Therefore, we speculate that miR-10a-5p may be involved in the transformation of muscle fiber types by targeting the MYHBP gene. In addition, PPI analysis of differentially expressed mRNA genes showed that ACTC1, ACTG2 and ACTN2 gene had the highest node degree, suggesting that this gene may play a key role in the regulatory network of muscle fiber type determination. CONCLUSIONS: We can conclude that these genes play a key role in regulating muscle fiber type transformation. Our study provides transcriptomic profiles and ceRNA interaction networks for different muscle fiber types in pigs, providing reference for the transformation of pig muscle fiber types and the improvement of meat quality.

Research progress of human key DNA and RNA methylation-related enzymes assay.

Gene methylation-related enzymes (GMREs) are disfunction and aberrantly expressed in a variety of cancers, such as lung, gastric, and pancreatic cancers and have important implications for human health. Therefore，it is critical for early diagnosis and therapy of tumor to develop strategies that allow rapid and sensitive quantitative and qualitative detection of GMREs. With the development of modern analytical techniques and the application of various biosensors, there are numerous methods have been developed for analysis of GMREs. Therefore, this paper provides a systematic review of the strategies for level and activity assay of various GMREs including methyltransferases and demethylase. The detection methods mainly involve immunohistochemistry, colorimetry, fluorescence, chemiluminescence, electrochemistry, etc. Then, this review also addresses the coordinated role of various detection probes, novel nanomaterials, and signal amplification methods. The aim is to highlight potential challenges in the present field, to expand the analytical application of GMREs detection strategies, and to meet the urgent need for future disease diagnosis and intervention.

Complete Mitochondrial Genomes of Nedyopus patrioticus: New Insights into the Color Polymorphism of Millipedes.

There has been debate about whether individuals with different color phenotypes should have different taxonomic status. In order to determine whether the different color phenotypes of Nedyopus patrioticus require separate taxonomic status or are simply synonyms, here, the complete mitochondrial genomes (mitogenomes) of two different colored N. patrioticus, i.e., red N. patrioticus and white N. patrioticus, are presented. The two mitogenomes were 15,781 bp and 15,798 bp in length, respectively. Each mitogenome contained 13 PCGs, 19 tRNAs, 2 rRNAs, and 1 CR, with a lack of trnI, trnL2, and trnV compared to other Polydesmida species. All genes were located on a single strand in two mitogenomes. Mitochondrial DNA analyses revealed that red N. patrioticus and white N. patrioticus did not show clear evolutionary differences. Furthermore, no significant divergence was discovered by means of base composition analysis. As a result, we suggest that white N. patrioticus might be regarded as a synonym for red N. patrioticus. The current findings confirmed the existence of color polymorphism in N. patrioticus, which provides exciting possibilities for future research. It is necessary to apply a combination of molecular and morphological methods in the taxonomy of millipedes.

Comparing the effectiveness of caries arrest by micro-operative treatment to operative treatment: A 2-year randomized controlled clinical trial.

OBJECTIVES: To compare the effectiveness of caries arrest by micro-operative treatment (sealing) to operative treatment (flowable resin composite restoration) through a 2-year randomized controlled clinical trial. MATERIALS AND METHODS: A prospective randomized controlled trial was conducted among 7-9-year-old children. At baseline, 630 subjects were screened and 92 children who had at least one carious lesion classified as ICDAS 3 on the pit and fissure of first permanent molar were included. Then they were randomly assigned to the sealant group (73 lesions) and the flowable resin composite group (76 lesions) to receive the corresponding intervention. Lesions status in each group was evaluated every 6 months up to 24 months. Clinical progression of dental caries and materials retention were the outcomes used for group comparisons at p-value < 0.05. RESULTS: After 24 months, three lesions (4.1%) in the sealant group clinically progressed to dentin caries. No lesion in the flowable composite group was observed a progression. The results of Life-table survival analysis show that the cumulative caries arrest rate had no statistically significant difference between the two groups (p = 0.075). However, the cumulative retention rate was 57.5% in the sealant group and 92.1% in the flowable composite group, with significant differences (p < 0.001). The multilevel mixed model showed the sealant had higher risk of retention failure than the flowable composite (OR = 8.66, p < 0.001), while tooth position did not influence material retention (p = 0.083). In addition, the results of Fisher Exact test show that dentin lesions had more retention failure than enamel lesions in the sealant group (p = 0.026). CONCLUSION: Although sealing microcavitated carious lesions of the first permanent molar achieved lower retention rate than resin composite restoration, both sealing and restoration effectively arrested caries progression for two years. CLINICAL RELEVANCE: To preserving dental structure and delaying or eliminating the need for operative procedures, microcavitated carious lesion can be arrested by sealing. TRIAL REGISTRATION: Registered at http://www.chictr.org.cn ; Feb 15th, 2020; No. ChiCTR2000029862.

YOLOv8-ACU: improved YOLOv8-pose for facial acupoint detection.

Introduction: Acupoint localization is integral to Traditional Chinese Medicine (TCM) acupuncture diagnosis and treatment. Employing intelligent detection models for recognizing facial acupoints can substantially enhance localization accuracy. Methods: This study introduces an advancement in the YOLOv8-pose keypoint detection algorithm, tailored for facial acupoints, and named YOLOv8-ACU. This model enhances acupoint feature extraction by integrating ECA attention, replaces the original neck module with a lighter Slim-neck module, and improves the loss function for GIoU. Results: The YOLOv8-ACU model achieves impressive accuracy, with an mAP@0.5 of 97.5% and an mAP@0.5-0.95 of 76.9% on our self-constructed datasets. It also marks a reduction in model parameters by 0.44M, model size by 0.82 MB, and GFLOPs by 9.3%. Discussion: With its enhanced recognition accuracy and efficiency, along with good generalization ability, YOLOv8-ACU provides significant reference value for facial acupoint localization and detection. This is particularly beneficial for Chinese medicine practitioners engaged in facial acupoint research and intelligent detection.

The First Complete Mitochondrial Genome of the Genus Litostrophus: Insights into the Rearrangement and Evolution of Mitochondrial Genomes in Diplopoda.

This study presents the complete mitochondrial genome (mitogenome) of Litostrophus scaber, which is the first mitogenome of the genus Litostrophus. The mitogenome is a circular molecule with a length of 15,081 bp. The proportion of adenine and thymine (A + T) was 69.25%. The gene ND4L used TGA as the initiation codon, while the other PCGs utilized ATN (A, T, G, C) as the initiation codons. More than half of the PCGs used T as an incomplete termination codon. The transcription direction of the L. scaber mitogenome matched Spirobolus bungii, in contrast to most millipedes. Novel rearrangements were found in the L. scaber mitogenome: trnQ -trnC and trnL1- trnP underwent short-distance translocations and the gene block rrnS-rrnL-ND1 moved to a position between ND4 and ND5, resulting in the formation of a novel gene order. The phylogenetic analysis showed that L. scaber is most closely related to S. bungii, followed by Narceus magnum. These findings enhance our understanding of the rearrangement and evolution of Diplopoda mitogenomes.

Leveraging chromatin state transitions for the identification of regulatory networks orchestrating heart regeneration.

The limited regenerative capacity of the human heart contributes to high morbidity and mortality worldwide. In contrast, zebrafish exhibit robust regenerative capacity, providing a powerful model for studying how to overcome intrinsic epigenetic barriers maintaining cardiac homeostasis and initiate regeneration. Here, we present a comprehensive analysis of the histone modifications H3K4me1, H3K4me3, H3K27me3 and H3K27ac during various stages of zebrafish heart regeneration. We found a vast gain of repressive chromatin marks one day after myocardial injury, followed by the acquisition of active chromatin characteristics on day four and a transition to a repressive state on day 14, and identified distinct transcription factor ensembles associated with these events. The rapid transcriptional response involves the engagement of super-enhancers at genes implicated in extracellular matrix reorganization and TOR signaling, while H3K4me3 breadth highly correlates with transcriptional activity and dynamic changes at genes involved in proteolysis, cell cycle activity, and cell differentiation. Using loss- and gain-of-function approaches, we identified transcription factors in cardiomyocytes and endothelial cells influencing cardiomyocyte dedifferentiation or proliferation. Finally, we detected significant evolutionary conservation between regulatory regions that drive zebrafish and neonatal mouse heart regeneration, suggesting that reactivating transcriptional and epigenetic networks converging on these regulatory elements might unlock the regenerative potential of adult human hearts.

The Role of Phase Mixing Degree in Promoting C-C Coupling in Electrochemical CO2 Reduction Reaction on Cu-based Catalysts.

Cu-based catalysts have been identified as the most promising candidates for generation of C2+ products in electrochemical CO2 reduction reaction. Defect engineering in catalysts is a widely employed strategy for promoting C-C coupling on Cu. However, comprehensive understanding of defect structure-to-activity relationship has not been obtained. In this study, controllable defects generation is achieved, which leads to a series of Cu-based catalysts with various phase mixing degrees. It is observed that the Faradaic efficiency toward C2+ products increases with the phase mixing degree, reaching 81 % at maximum. In situ infrared absorption spectroscopy reveals that the catalysts with higher phase mixing degree tend to form *CO more easily and possess higher retention of *CO under high overpotential window, thereby promoting C-C coupling. This work sheds new light on the relationship between defects and C-C coupling, and the rational developed of more advanced Cu-base catalysts.