CD38 deficiency prevents diabetic nephropathy by inhibiting lipid accumulation and oxidative stress through activation of the SIRT3 pathway.

Diabetic nephropathy (DN) is one of the most common complications of diabetes. Our previous study showed that CD38 knockout (CD38KO) mice had protective effects on many diseases. However, the roles and mechanisms of CD38 in DN remain unknown. Here, DN mice were generated by HFD feeding plus streptozotocin (STZ) injection in male CD38KO and CD38flox mice. Mesangial cells (SV40 MES 13 cells) were used to mimic the injury of DN with palmitic acid (PA) treatment in vitro. Our results showed that CD38 expression was significantly increased in kidney of diabetic CD38flox mice and SV40 MES 13 cells treated with PA. CD38KO mice were significantly resistant to diabetes-induced renal injury. Moreover, CD38 deficiency markedly decreased HFD/STZ-induced lipid accumulation, fibrosis and oxidative stress in kidney tissue. In contrast, overexpression of CD38 aggravated PA-induced lipid accumulation and oxidative stress. CD38 deficiency increased expression of SIRT3, while overexpression of CD38 decreased its expression. More importantly, 3-TYP, an inhibitor of SIRT3, significantly enhanced PA-induced lipid accumulation and oxidative stress in CD38 overexpressing cell lines. In conclusion, our results demonstrated that CD38 deficiency prevented DN by inhibiting lipid accumulation and oxidative stress through activation of the SIRT3 pathway.

A novel fucoxanthin enriched seaweed gummy: Physicochemical qualities and protective effect on UVB-induced retinal müller cells.

Retinal disease has become the major cause of visual impairment and vision loss worldwide. Carotenoids, which have the potential antioxidant and eye-care activities, have been widely used in functional foods. Our previous study showed that fucoxanthin could exert photoprotective activity in UVB-induced retinal müller cells (RMCs). To extend the application of fucoxanthin in food industry, fucoxanthin, Undaria pinnatifida pulp (UPP), carrageenan, and other ingredients were mixed to prepare seaweed-flavoured photoprotective gummies in this study. The structural and functional properties of the gummies were then evaluated by physicochemical test and cell experiments. As a result, fucoxanthin enriched gummies presented favourable structural properties and flavour. The hydroxyl groups in fucoxanthin and κ-carrageenan are bonded through hydrogen bonds, forming the spatial network structure inside the gummies, enhancing its elasticity. The gummies showed significant antioxidant effect and alleviated the UVB oxidation damage in RMCs. Moreover, the main ingredients carrageenan and UPP improved the stability of fucoxanthin during in vitro digestion. The results enhance the application of fucoxanthin in functional food with photoprotective activity.

LARP1, an RNA-binding protein, participates in ovarian cancer cell survival by regulating mitochondrial oxidative phosphorylation in response to the influence of the PI3K/mTOR pathway.

Targeting the PI3K/mTOR pathway and modulating mitochondrial adaptation is expected to be a critical approach for cancer therapy. Although the regulation of mitochondria by the PI3K/mTOR pathway has been investigated, it is not well understood due to the complexity of its regulatory mechanisms. RNA-binding proteins (RBPs) selectively regulate gene expression through post-transcriptional modulation, playing a key role in cancer progression. LARP1, a downstream RBP of the mTOR pathway, is involved in mitochondria-mediated BCL-2 cell survival. Therefore, exploring the involvement of LARP1 in PI3K/mTOR-mediated translational regulation of mitochondria-associated proteins in ovarian cancer cells could help elucidate the role of mitochondria in the PI3K/mTOR pathway. We found that, unlike SKOV3 cells, the mitochondrial function of A2780 cells was not affected, which were insensitive to the dual PI3K/mTOR inhibitor PKI-402, suggesting that cell survival may be related to mitochondrial function. Knockdown of the LARP1 gene after PKI-402 treatment resulted in impaired mitochondrial function in A2780 cells, possibly due to decreased mRNA stability and reduced protein translation of the mitochondrial transcription initiation factor, TFB2M, and the respiratory chain complex II subunit, SDHB. LARP1 affects protein translation by binding to TFB2M mRNA, regulating mitochondrial DNA-encoded genes, or indirectly regulating the nuclear DNA-encoded SDHB gene, ultimately interfering with mitochondrial oxidative phosphorylation and leading to apoptosis. Therefore, LARP1 may be an important mediator in the PI3K/mTOR pathway for regulating mRNA translation and mitochondrial function. Targeting RBPs such as LARP1 downstream of the mTOR pathway may provide new insights and potential therapeutic approaches for ovarian cancer treatment.

Presumed atypical late-onset toxic anterior segment syndrome after implantable collamer lens implantation: a case report.

BACKGROUND: Toxic anterior segment syndrome (TASS) is a rare, noninfectious inflammation that occurs after anterior segment surgery. We report a case herein that developed presumed atypical late-onset TASS after V4c implantable collamer lens (ICL) implantation surgery. CASE PRESENTATION: A 26-year-old man underwent ICL implantation surgeries of both eyes on two separate days. The 1-day and 7-day postoperative routine follow-up visits revealed no abnormalities. However, one month after surgery, dense white spots attached to the posterior surface and scattered ones to the anterior surface of ICL in the left eye were noted on anterior segment examination. His uncorrected distance visual acuity (UDVA) was 20/16 in both eyes and the fundus examination was normal. Despite the absence of typical clinical manifestations, late-onset TASS was suspect and intense topical steroid was administered. After 6 weeks of tapering topical steroid therapy, the white spots disappeared and the patient had no subjective complains throughout the treatment period. CONCLUSIONS: This case suggested that the traditionally considered acute and serious TASS could also present as delayed and insidious onset after ICL implantation surgery. Due to its variabilities, the awareness of TASS should be raised to ophthalmologists and regular follow-up visits should be emphasized to patients. Once TASS was suspected, intensive steroid therapy should be implemented in time.

Radiopaque and Biocompatible PMMA Bone Cement Triggered by Nano Tantalum Carbide and Its Osteogenic Performance.

Poly(methyl methacrylate) (PMMA) bone cements have been widely used in orthopedics; thanks to their excellent mechanical properties, biocompatibility, and chemical stability. Barium sulfate and zirconia are usually added into PMMA bone cement to enhance the X-ray radiopacity, while the mechanical strength, radiopacity, and biocompatibility are not well improved. In this study, an insoluble and corrosion-resistant ceramic, tantalum carbide (TaC), was added into the PMMA bone cement as radiopacifies, significantly improving the mechanical, radiopaque, biocompatibility, and osteogenic performance of bone cement. The TaC-PMMA bone cement with varied TaC contents exhibits compressive strength over 100 MPa, higher than that of the commercial 30% BaSO4-PMMA bone cement. Intriguingly, when the TaC content reaches 20%, the radiopacity is equivalent to the commercial bone cement with 30% of BaSO4 in PMMA. The cytotoxicity and osteogenic performance indicate that the incorporation of TaC not only enhances the osteogenic properties of PMMA but also does not reduce cell viability. This study suggests that TaC could be a superior and multifunctional radio-pacifier for PMMA bone cement, offering a promising avenue for improving patient outcomes in orthopedic applications.

Machine learning assisted microfluidics dual fluorescence flow cytometry for detecting bladder tumor cells based on morphological characteristic parameters.

BACKGROUND: Bladder cancer (BC) is the most common malignant tumor and has become a major public health problem, leading the causes of death worldwide. The detection of BC cells is of great significance for clinical diagnosis and disease treatment. Urinary cytology based liquid biopsy remains high specificity for early diagnosis of BC, however, it still requires microscopy examination which heavily relies on manual operations. It is imperative to investigate the potential of automated and indiscriminate cell differentiation technology to enhance the sensitivity and efficiency of urine cytology. RESULTS: Here, we developed a machine learning algorithm empowered dual-fluorescence flow cytometry platform (µ-FCM) for urinary cytology analysis. A phenotype characteristic parameter (CP) which correlated with the size of the cell and nucleus was defined to achieve the differentiation of the BC cells and uroepithelial cells with high throughput and high accuracy. Based on CP analysis, SV-HUC-1 cells were almost differentiated from EJ cells and effectively reduced the overlap with 5637 cells. To further differentiate SV-HUC-1 cells and 5637 cells, support vector machine (SVM) machine learning algorithm was optimized to assist data analysis with the highest accuracies of 84.7 % for cell differentiation including the specificity of 91.0 % and the sensitivity of 75.0 %. Furthermore, the false positive rate (FPR) compensation enabled the detection rates of rare BC cells predicted by the well-trained SVM model were close to the true proportions with the recognition error in 0.4 % for the tumor cells. SIGNIFICANCE: As a proof of concept, the developed µ-FCM system successfully demonstrates the capacity to identify the distribution of exfoliated cells in real urine samples. This system underscores the significance of integrating AI with microfluidics to perform high-throughput phenotyping of exfoliated cells, offering a pathway toward scalable, efficient, and automatic microfluidic systems in the fields of both biosensing and in vitro diagnosis of BC.

Quercetin protects against hypertensive renal injury by attenuating apoptosis: an integrated approach using network pharmacology and RNA-Seq.

Quercetin is kown for its antihypertensive effects. However, its role on hypertensive renal injury has not been fully eucidated. In this study, hematoxylin and eosin staining, terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) staining, and Annexin V staining were used to assess the pathological changes and cells apoptosis in the renal tissues of Ang II-infused mice and Ang II- stimulated renal tubular epithelial cell line (NRK-52E). A variety of technologies, including network pharmacology, RNA-sequencing, immunohistochemistry, and Western blotting were performed to investigate its underlying mechanisms. Network pharmacology analysis identified multiple potential candidate targets (including TP53, Bcl-2 and Bax) and enriched signaling pathways (including apoptosis and p53 signaling pathway). Quercetin treatment significantly alleviated the pathological changes in renal tissues of Ang II-infused mice and reversed 464 differentially expressed transcripts (DETs), as well as enriched several signaling pathways, including those related apoptosis and p53 pathway. Furthermore, quercetin treatment significantly inhibited the cell apoptosis in renal tissues of Ang II-infused mice and Ang II-stimulated NRK-52E cells. Additionally, quercetin treatment inhibited the upregulation of p53, Bax, cleaved-caspase-9, and cleaved-caspase-3 protein expression and the downregulation of Bcl-2 protein expression in both renal tissue of Ang II-infused mice and Ang II-stimulated NRK-52E cells. Moreover, the molecular docking results indicated a potential binding interaction between quercetin and TP53. Quercetin treatment significantly attenuated hypertensive renal injury and cell apoptosis in renal tissues of Ang II-infused mice and Ang II-stimulated NRK-52E cells, and by targeting p53 may be one of the potential underlying mechanisms.

The influence of drying methods on extract content, tyrosinase activity inhibition, and mechanism in Ascophyllum nodosum: A combined microstructural and kinetic study.

This study evaluates vacuum drying (VD), microwave drying (MD), hot air drying (HAD), and freeze drying (FD), on the color and microstructure changes of Ascophyllum nodosum (A. nodosum), which affect the extraction of polyphenols and flavonoids. During drying, VD and FD show slight color change and looser structure, aiding in active compound preservation and extraction. Polyphenols extracted from A. nodosum (PEAn) using these methods show higher anti-tyrosinase activity, with VD treatment exhibiting the strongest inhibition. Kinetic studies demonstrate competitive inhibition between PEAn and tyrosinase. The binding constant (Ki) values indicate that PEAn treated with VD exhibits the most effective inhibition on tyrosinase, and the Zeta potential suggests the formation of the most stable complex. Circular dichroism (CD) spectroscopy shows significant enzyme rearrangement with VD-treated PEAn. Molecular docking confirms strong binding affinity. This study aims to enhance the utility of A. nodosum and develop novel uses for tyrosinase inhibitors in food.

Dataset of core and differentially abundant bacteria in various compartments of farm-cultivated and home-planted chilli plants (Capsicum frutescens).

Chillies are members of the genus Capsicum L. (family Solanaceae). They are native to Central and South America and consist of approximately 35 species [1,2]. Among these, five species (C. annuum L., C. baccatum L., C. chinense Jacq., C. frutescens L., and C. pubescens Ruiz & Pav.) have been domesticated and are mainly cultivated for consumption as vegetables and spices. Of the domesticated chillies, C. annuum is commercially cultivated worldwide, while C. frutescens and C. chinense are mainly cultivated in American, Asian, and African countries [3]. We compared the diversity of microbiota in various compartments of farm-cultivated (FC) and home-planted (HP) chilli plants (Capsicum frutescens). Targeted 16S rRNA gene (V5-V6 region) was sequenced using the Illumina NovaSeq 6000 platform. Proteobacteria, Actinobacteriota, Acidobacteriota, Gemmatimonadota, Bacteroidota, and Firmicutes were present in all compartments of both the FC and HP plants. Proteobacteria (or Pseudomonadota) was the predominant phylum in all the compartments of both HP and FC plants, while Actinobacteriota (or Actinomycetota) was the second most abundant phylum. Most plant compartments (leaves, fruits and roots) exhibited a higher relative abundance of Proteobacteria compared to the soil samples. With few exceptions, the soil compartments (bulk and rhizospheric soils) displayed a higher relative abundance of the phyla Myxococcota, Acidobacteriota, Gemmatimonadota, Bacteroidota, Nitrospirota, Verrucomicrobiota, and Firmicutes than the plant compartments. Diversity indices revealed that the bacterial community in chili plants clustered based on both compartment and cultivation area.

Course-based intra-articular injection of medical chitosan mitigates excessive deposition of triacylglycerides in the synovial tissue of the knee osteoarthritis.

BACKGROUND: This study aimed to investigate the clinical efficacy of intra-articular injections of medical chitosan for treating knee osteoarthritis (KOA) and measure the lipid metabolism profiles of the synovial tissue. METHODS: 60 patients with KOA undergoing conservative treatment were recruited and randomized into two groups: one without pharmacological intervention (OA group) and the other receiving course-based intra-articular medical chitosan injections (CSI group). Quantitative lipidomic profile of synovial tissue was analyzed. Functional scores, including Kellgren-Lawrence rating (K-L), VAS, WOMAC scoring, and AKS scoring were conducted. RESULTS: Survival from the initial conservative treatment to final knee arthroplasty was significantly longer in the CSI group compared to the OA group. Except for the pre-surgery VAS score, no statistically significant differences were observed in the other scores, including K-L, initial VAS, WOMAC, and AKS. However, the CSI group experienced a slightly more pronounced decline in AKS-Knee subscores compared to the OA group. Compared to the CSI group, the OA group exhibited a significant upregulation in most differential lipids, particularly triacylglycerides (TAGs, 77%). The OA group had notably higher levels of long-chain unsaturated fatty acids. CONCLUSION: Intra-articular injection of medical chitosan significantly prolongs the survival period before knee arthroplasty and reduces the deposition of TAGs metabolites.

Phycocyanin-phlorotannin complexes improve the structure and functional properties of yogurt.

Adding natural bioactive ingredients to yogurt can improve the nutritional and physiological benefits. In this study, we used ultrasonic-assisted phlorotannin from Ascophyllum nodosum (A. nodosum) modified phycocyanin (PC) to form a complex (UPP) to produce a fortified fermented yogurt. The effects of PC and UPP on the structure, stability, and function of fermented yogurt within 7 days were assessed using physicochemical properties, texture analysis, rheological testing, 16S rDNA sequencing analysis, and lipidomics analysis. Molecular docking indicated that PC might bind to phlorotannin via ARG-77, ARG-84, LEU-120, ALA-81, CYS-82, and ASP-85 sites.When the mass ratio of the complex is 1:1, the ability of UPP1:1 to remove DPPH· scavenging ability in an acid environment increased by about 50 %. UPP1:1 with more acid stability changed the microstructure of the yogurt, enhanced the stability of the yogurt, improved the antioxidant properties, and inhibited the growth of harmful bacteria within 7 days. This work encouraged the extraction and use of phlorotannin from edible brown algae and offered a straightforward method for making yogurt supplemented with PC.

Formation of chlorophyll-anionic polysaccharide complex coacervates to improve chlorophyll color stability: Thermodynamic and kinetic stability studies.

Chlorophyll (Chl) is the predominant pigment in green plants that can act as a food color and possesses various functional activities. However, its instability and rapid degradation on heating compromise the sensory qualities of its products. This study aimed to enhance the heat resistance of Chl by forming complex coacervates with two negatively charged polysaccharides, sodium alginate (SA) and K-carrageenan (KC). Dynamic light scattering and scanning electron microscopy analyses confirmed the formation of coacervates between Chl and the polysaccharides, whereas Fourier-transform infrared spectroscopy revealed that hydrogen bonding and electrostatic attraction were the primary forces behind complex formation. Electron spin resonance and thermodynamic studies further revealed that these complexes bolstered the thermal stability of Chl, with a maximum improvement of 70.38 % in t1/2 and a reduction of 50.72 % in the degradation rate constant. In addition, the antioxidant capacity of Chl was enhanced up to 35 %. Therefore, this study offers a novel approach to Chl preservation and suggests a viable alternative to artificial pigments in food products.

miR-4443 Contained Extracellular Vesicles: A Factor for Endometriosis Progression by PI3K/AKT/ACSS2 Cascade in-vitro.

Introduction: Endometriosis (EM) is an estrogen-dependent benign gynecologic disease affecting approximately 10% of reproductive-age women with a high recurrence rate, but lacks reliable biomarkers. No previous studies have investigated the possible use of extracellular vesicle (EV)-associated micro RNAs (miRNAs) from menstrual blood (MB) as candidate diagnostic or prognostic markers of EM. Methods: Specimens were obtained from endometriosis and non-endometriosis patients at the International Peace Maternity and Child Health Hospital in Shanghai. Microarray was used to screen differentially expressed miRNAs among peritoneal fluid (PF), fallopian tube fluid (FF), and MB. Dual-luciferase reporter gene assay was carried out to verify the relationship between miR-4443 and ACSS2. Cell proliferation and Transwell invasion assays were performed in vitro after intervention on miR-4443 and ACSS2 in hEM15A human endometrial stromal cells and primary human endometrial stromal cells (hESCs). Spearman correlation analysis, receiver operating characteristic (ROC) curve analysis, and survival analysis were applied to clinical data, including severity of symptoms and relapse of EM among EM patients. Results: EV-associated miR-4443 was abundant in MB of endometriosis patients. ACSS2 knockdown and miR-4443 overexpression promoted cell proliferation and migration via the PI3K/AKT pathway. miR-4443 levels in MB-EVs were positively correlated with the degree of dyspareunia (r=0.64; P<0.0001) and dysmenorrhea (r=0.42; P<0.01) in the endometriosis group. ROC curve analyses showed an area under the curve (AUC) of 0.741 (95% CI 0.624-0.858; P<0.05) for miR-4443 and an AUC of 0.929 (95% CI 0.880-0.978; P<0.05) for the combination of miR-4443 and dysmenorrhea. Conclusion: MB-derived EV-associated miR-4443 might participate in endometriosis development, thus providing a new candidate biomarker for the noninvasive prediction of endometriosis recurrence.

[Retracted] Molecular hydrogen improves type 2 diabetes through inhibiting oxidative stress.

[This retracts the article DOI: 10.3892/etm.2020.8708.].

Young patient with a giant gastric bronchogenic cyst: A case report and review of literature.

BACKGROUND: Gastric bronchogenic cysts (BCs) are extremely rare cystic masses caused by abnormal development of the respiratory system during the embryonic period. Gastric bronchial cysts are rare lesions that were first reported in 1956; as of 2023, only 33 cases are available in the PubMed online database. BCs usually have no clinical symptoms in the early stage, and imaging findings also lack specificity. Therefore, they are difficult to diagnose before histopathological examination. CASE SUMMARY: A 34-year-old woman with respiratory distress presented at our hospital. Endoscopic ultrasound revealed an anechoic mass between the spleen, left kidney and gastric fundus, with hyperechogenic and soft elastography textures and with a size of approximately 6.5 cm × 4.0 cm. Furthermore, a computed tomography scan demonstrated high density between the posterior stomach and the spleen and the left kidney, with uniform internal density and a small amount of calcification. The maximum cross section was approximately 10.1 cm × 6.1 cm, and the possibility of a cyst was high. Because the imaging findings did not suggest a malignancy and because the patient required complete resection, she underwent laparotomy surgery. Intraoperatively, this cystic lesion was found to be located in the posterior wall of the large curvature of the fundus and was approximately 8 cm × 6 cm in size. Finally, the pathologists verified that the cyst in the fundus was a gastric BC. The patient recovered well, her symptoms of chest tightness disappeared, and the abdominal drain was removed on postoperative day 6, after which she was discharged on day 7 for 6 months of follow-up. She had no tumor recurrence or postoperative complications during the follow-up. CONCLUSION: This is a valuable report as it describes an extremely rare case of gastric BC. Moreover, this was a very young patient with a large BC in the stomach.

Characterization of flavor substances in cooking and seasoned cooking brown seaweeds by GC-IMS and E-nose.

The flavor of algae was one of the key factors for consumer acceptance. The objective of this study was to investigate the characteristic volatile compounds in cooking and seasoned cooking edible brown seaweeds (Undaria pinnatifida and Laminaria japonica). The gas chromatography-ion mobility spectrometry (GC-IMS) and electronic nose (E-nose) analysis showed that baking resulted in significant difference in flavor of brown seaweeds. However, the overall effect of cooking was not as significant as that of the seasoning solution treatment. Additionally, brown seaweeds treated with the seasoning solution were more acceptable. Undaria pinnatifida was found to contain 72 volatile flavor compounds, while Laminaria japonica had a total of 70. This study proved the applicability of GC-IMS combined with E-nose technology to detect the changes of volatile components of brown seaweeds after processing, providing beneficial knowledge and basic theory for the deep processing of brown seaweeds.

Role of hepatitis B core-related antigen in predicting the occurrence and recurrence of hepatocellular carcinoma in patients with chronic hepatitis B: A systemic review and meta-analysis.

BACKGROUND AND AIM: The purpose of the current study was to investigate the predictive value of hepatitis B core-related antigen (HBcrAg) on the occurrence and recurrence of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). METHODS: We searched PubMed, Embase, Scopus, and Web of Science from database inception to April 6, 2023. Pooled hazard ratio (HR) or odds ratio (OR) with 95% confidence interval (CI) was calculated for the occurrence and recurrence of HCC. RESULTS: Of the 464 articles considered, 18 articles recruiting 10 320 patients were included. The pooled results showed that high serum HBcrAg level was an independent risk factor for the occurrence of HCC in CHB patients (adjusted HR = 3.12, 95% CI: 2.40-4.06, P < 0.001, I2 = 43.2%, P = 0.043; OR = 5.65, 95% CI: 3.44-5.82, P < 0.001, I2 = 0.00%, P = 0.42). Further subgroup analysis demonstrated that the predictive ability of HBcrAg for the occurrence of HCC is not influenced by the hepatitis B e antigen (HBeAg) status or the use of nucleoside/nucleotide analogs (NAs). In addition, our meta-analysis also suggests that HBcrAg is a predictor of HCC recurrence (adjusted HR = 1.71, 95% CI: 1.26-2.32, P < 0.001, I2 = 7.89%, P = 0.031). CONCLUSIONS: For patients with CHB, serum HBcrAg may be a potential predictive factor for the occurrence of HCC, regardless of HBeAg status or NA treatment. It may also serve as a novel prognostic biomarker for the recurrence of HCC. More studies are needed to confirm our conclusions.

Ultrahigh-reflective optical thin films prepared by reactive magnetron sputtering with RF-induced substrate bias.

Optical thin films with high-reflectivity (HR) are essential for applications in quantum precision measurements. In this work, we propose a coating technique based on reactive magnetron sputtering with RF-induced substrate bias to fabricate HR-optical thin films. First, atomically flat SiO2 and Ta2O5 layers have been demonstrated due to the assistance of radio-frequency plasma during the coating process. Second, a distributed Bragg reflector (DBR) mirror with an HR of ∼99.999 328% centered at 1397 nm has been realized. The DBR structure is air-H{LH}19-substrate, in which the L and H denote a single layer of SiO2 with a thickness of 237.8 nm and a single layer of Ta2O5 with a thickness of 171.6 nm, respectively. This novel coating method would facilitate the development of HR reflectors and promote their wide applications in precision measurements.

Polyphenol oxidase mediates (-)-epigallocatechin gallate to inhibit endogenous cathepsin activity in Apostichopus japonicus.

Apostichopus japonicus (A. japonicus) has rich nutritional value and is an important economic crop. Due to its rich endogenous enzyme system, fresh A. japonicus is prone to autolysis during market circulation and storage, resulting in economic losses. In order to alleviate this phenomenon, we investigated the effect of polyphenol oxidase (PPO) mediated (-)-epigallocatechin gallate (EGCG) on the activity and structure of endogenous cathepsin series protein (CEP) from A. japonicus. Research on cathepsin activity showed that PPO mediated EGCG could significantly reduce enzyme activity, resulting in a decrease in enzymatic reaction rate. SDS-PAGE and scanning electron microscopy results showed that PPO mediates EGCG could induce CEP aggregation to form protein aggregates. Various spectral results indicated that EGCG caused changes in the structure of CEP. Meanwhile, the conjugates formed by PPO mediated EGCG had lower thermal stability. In conclusion, PPO mediated EGCG was an effective method to inhibit the endogenous enzyme activity.