Staphylococcus aureus is a Gram-positive bacterium with strong pathogenicity. With the widespread use of antibiotics， its multi-drug resistance has gradually increased. Among them， methicillin-resistant S. aureus （MRSA） is one of the main pathogens of hospital and community infections. Antimicrobial peptides are short-chain peptides with good antibacterial effects and low drug resistance， which have been widely studied in recent years. This study summarizes the mechanism of action of antimicrobial peptides and related study on antimicrobial peptides against MRSA from different sources. It is found that the mechanisms of action of antimicrobial peptides include targeting bacterial cell membranes， bacterial cells， and bacterial cell walls， etc. Besides isolating antimicrobial peptides with anti-MRSA activity from animals， plants， and microorganisms， antimicrobial peptides can also be obtained through synthetic methods. Among them， GHa-derived peptides from animal sources， Ib-AMP4 from plant sources， Ph-SA from microbial sources， the synthetic peptide LLKLLLKLL-NH2， and so on， due to their effective antibacterial activity， rapid bactericidal speed， and low toxicity， are promising candidates for anti-MRSA drugs.

As the need for antibody production rises, there is an urgent need to lower the costs and enhance the efficiency of the separation process. Currently, the chromatographic media used for antibody separation and purification often focus on individual properties of antibodies, such as affinity, hydrophobicity, and charge, leading to issues like low purification efficiency or inadequate adsorption capacity. To address this, an electrostatically coupled polypeptide affinity medium (FD7-3, 5-diaminobenzoic acid n-sepharose, FD7-DA-Sepharose) was developed for rapid purification of antibodies from cell culture supernatant. This medium utilized 3, 5-diaminobenzoic acid as a spacer to attach the heptapeptide-affinity ligand (FYEILHD, FD7) to agarose microspheres. Antibodies could be adsorbed through charge interactions with the carboxyl functional group of the FD7-DA-Sepharose spacer, while FD7 enhanced electrostatic coupling and affinity adsorption through synergistic effects, significantly increasing the adsorption capacity while maintaining the affinity and specificity. The influences of pH and ionic strength on adsorption capacity were investigated with human immunoglobulin as a model protein. The static adsorption capacity (Q_m) of FD7-DA-Sepharose in the solution of pH 6.0 reached 67.73 mg/mL, representing a 52.68% increase compared with that (44.36 mg/mL) of the commercial Protein A affinity medium. Furthermore, the elution conditions for FD7-DA- Sepharose were mild (20 mmol/L PB, 0.5 mol/L NaCl, pH 6.0), in contrast to the harsh acidic elution (pH 2.7-3.6) typically associated with Protein A, which can damage antibody integrity. The FD7-DA-Sepharose medium was then employed to purify antibodies from cell culture supernatant, achieving the yield of 94.8% and the purity of 98.4%. The secondary structure of the purified antibody was determined by circular dichroism spectroscopy. The results demonstrated that FD7-DA-Sepharose enabled efficient purification of antibodies from cell culture supernatant, which provided a cost-effective solution (approximately one-third the price of commercial Protein A affinity medium) with gentle elution conditions that preserve the natural conformation of antibodies. This approach paves a novel, economical, and efficient way for the separation and purification of antibodies from cell culture supernatant.
Chromatography, Affinity/methods* ; Static Electricity ; Humans ; Sepharose/analogs & derivatives* ; Peptides/chemistry* ; Adsorption ; Antibodies/isolation & purification*

Coronary restenosis is an important cause of poor long-term prognosis in patients with coronary heart disease. Here, we show that lysine methyltransferase SMYD2 expression in the nucleus is significantly elevated in serum- and PDGF-BB-induced vascular smooth muscle cells (VSMCs), and in tissues of carotid artery injury-induced neointimal hyperplasia. Smyd2 overexpression in VSMCs (Smyd2-vTg) facilitates, but treatment with its specific inhibitor LLY-507 or SMYD2 knockdown significantly inhibits VSMC phenotypic switching and carotid artery injury-induced neointima formation in mice. Transcriptome sequencing revealed that SMYD2 knockdown represses the expression of serum response factor (SRF) target genes and that SRF overexpression largely reverses the inhibitory effect of SMYD2 knockdown on VSMC proliferation. HDAC3 directly interacts with and deacetylates SRF, which enhances SRF transcriptional activity in VSMCs. Moreover, SMYD2 promotes HDAC3 expression via tri-methylation of H3K36 at its promoter. RGFP966, a specific inhibitor of HDAC3, not only counteracts the pro-proliferation effect of SMYD2 overexpression on VSMCs, but also inhibits carotid artery injury-induced neointima formation in mice. HDAC3 partially abolishes the inhibitory effect of SMYD2 knockdown on VSMC proliferation in a deacetylase activity-dependent manner. Our results reveal that the SMYD2-HDAC3-SRF axis constitutes a novel and critical epigenetic mechanism that regulates VSMC phenotypic switching and neointimal hyperplasia.

Objective To investigate the effects of DNA demethylation drugs combined with histone deacetylase in-hibitors on fragile X mental retardation 1 neighbor protein (FMR1NB) expression and its promoter methylation in human oral cancer cells and try to find a strategy of weakening the heterogeneity of FMR1NB expression.Methods Human oral cancer cell lines Cal27 and SCC-9 were treated with decitabine (DAC) , an inhibitor of DNA meth-yltransferase, combined with trichostatin A (TSA) and valproic acid (VPA), inhibitors of histone deacetylase.Then reverse transcription-polymerase chain reaction (RT-PCR) , quantitative real-time PCR (qRT-PCR) and Western blot were used to detect the expression of FMR1 NB and pyrosequencing was used to detect the methylation of FMR1NB promoter.Results Compared with the blank control group, DAC and its combination with TSA and VPA significantly induced the expression of FMR1NB mRNA and protein in Cal27 and SCC-9 cells.Compared with DAC alone group, FMR1NB mRNA expression of each DAC-combined drug groups significantly increased, but FMR1NB protein did not significantly change in Cal27 cells; for SCC-9 cells, except for DAC+TSA group, the mRNA and protein levels of FMR1NB significantly increased in all other groups.In addition, there was no signifi-cant difference in the expression of FMR1 NB mRNA and protein between the three-combined drugs group and two-combined drugs groups.Further methylation assay showed that the methylation level of the overall FMR1NB promot-er and its each CpG site measured were reduced to varying degrees in all treatment groups except for three-combina-tion drug group of SCC-9.Conclusion DAC and its combination with TSA and VPA can enhance the expression of FMR1NB by mediating the demethylation of FMR1NB promoter, wherein the enhanced expression effect of the com-bination of the two drugs is stronger, suggesting that they have the potential to weaken the heterogeneity of FMR1NB expression and improve the immunotherapy effect of oral cancer.

The study adopted muscle injection of pVAX1-SP-GHRH(1-44)expression plasmid and electrostimulation to determine its effects on mouse growth and sow production performance.One hundred and fifty four-week-old C57 BL/6 female mice were randomly divided into 6 groups of 5 replicates each.Muscle single-injection followed by electrostimulation was performed.The con-trol group received an empty plasmid injection(80 μg/kg),while the treatment groups received pVAX1-SP-GHRH(1-44)plasmid injections(20,40,80,120,160 μg/kg).Twenty healthy preg-nant sows were randomly divided into 2 groups,each with 10 sows.Electrostimulation treatment was applied to the semimembranosus muscle of the pregnant sows after a single injection.The con-trol group received physiological saline injection,while the plasmid group received a 2 mg pVAX1-SP-GHRH(1-44)expression plasmid injection.Mouse weight,feed intake,and serum GHRH and IGF-1 levels were measured at days 0,7,14,21,and 28 after injection.Pregnant sows were bled via the tail vein at days 0,14,28,and 42 after injection,and their serum was separated to measure serum GHRH and IGF-1 levels.The birth weight,placental weight,number of piglets born,number of healthy piglets,number of weak piglets,number of deformed piglets,number of stillborn piglets,and number of mummified piglets were recorded at day 14.The mouse study re-sults showed that muscle injection of pVAX1-SP-GHRH(1-44)plasmid followed by electrostim-ulation could promote mouse feeding and increase weight gain(P＜0.05),significantly increase mouse serum GHRH and IGF-1 levels(P＜0.05),and maintain its effects until day 21.The results of the pregnant sow study showed that the average birth weight of the piglets in the plasmid group was significantly increased(P＜0.01),and the placenta weight was significantly increased(P＜0.05).The serum GHRH and IGF-1 concentrations in the plasmid group sows were significantly increased(P＜0.01).The study results showed that muscle injection of pVAX1-SP-GHRH(1-44)expression plasmid followed by electrostimulation could promote mouse feeding and increase weight gain,and also significantly improve the average birth weight and placental weight of the piglets in pregnant sows.

Objective To observe the value of quantitative CT(QCT)abdominal body fat parameters combined with clinical-imaging model for predicting recurrent acute pancreatitis(RAP).Methods Data of 468 patients with acute pancreatitis(AP),including 207 cases of RAP(RAP group)and 261 cases of non-RAP(non-RAP group)were retrospectively analyzed.Clinical information,conventional CT manifestations and QCT parameters such as abdominal subcutaneous fat area(SFA),visceral fat area(VFA),total abdominal fat area(TFA),hepatic fat content and pancreatic fat content at the first visit were recorded or measured.Clinical characteristics,CT manifestations and QCT parameter values were compared between groups,and the independent factors for predicting RAP were selected with multivariate logistic regression analysis.Then a clinical-imaging model and a comprehensive model combining with QCT parameters were constructed,and their efficacies for predicting RAP were evaluated with receiver operating characteristic(ROC)curves,and the area under the curves(AUC)were calculated.Results Compared with non-RAP group,patients in RAP group were younger,had higher percentage of alcohol consumption,biliary stones and hyperlipidemia,as well as of distinct pancreatic margins on CT images,also higher VFA,TFA,liver fat content and pancreatic fat content(all P＜0.05).Alcohol consumption,hyperlipidemia,biliary stones,pancreatic margins and pancreatic fat content were all independent predictors of RAP,and the comprehensive model constructed based on these five had higher AUC(0.860)than clinical-imaging model constructed based on the previous 4 factors(0.701)and pancreatic fat content alone(0.770)(both P＜0.001).Conclusion QCT abdominal body fat parameters combined with clinical-imaging comprehensive model was effective for predicting the risk of RAP.

Objective To investigate the value of quantitative CT(QCT)parameters related to abdominal and dorsal fat content for predicting early postoperative complications of esophageal cancer.Methods A total of 184 patients who underwent radical esophageal cancer surgery were retrospectively collected and divided into complication group(n=76)and control group(n=108)according to whether early postoperation complication(within 30 days after surgery)occurred or not.QCT was used to obtain parameters related to abdominal and dorsal fat content,including visceral fat area(VFA),subcutaneous fat area(SFA),VFA/SFA and the degree of muscle fat infiltration(MFI)of posterior vertebral muscles based on L3 central-level CT images.Univariate analysis and multivariate logistic regression were used to analyze clinical and pathological data as well as QCT parameters related to abdominal and dorsal fat content to screen independent risk factors for early postoperative complications of esophageal cancer.Then receiver operating characteristic(ROC)curve was drawn,and the area under the curve(AUC)was calculated to evaluate the efficacy of each independent risk factor alone and their combination for predicting early postoperative complications of esophageal cancer.Results VFA/SFA and MFI degree of posterior vertebral muscles were both independent risk factors for early postoperative complications of esophageal cancer(OR=5.121,1.110,both P＜0.05).The AUC of VFA/SFA and MFI degree of posterior vertebral muscle was 0.81 and 0.77,respectively,while of their combination was 0.84.Conclusion QCT parameters related to abdominal and dorsal fat content could be used to effectively predict early complications of esophageal cancer after surgery.

Background/Aims: The accuracy of endosonographers in diagnosing gastric subepithelial lesions (SELs) using endoscopic ultrasonography (EUS) is influenced by experience and subjectivity. Artificial intelligence (AI) has achieved remarkable development in this field. This study aimed to develop an AI-based EUS diagnostic model for the diagnosis of SELs, and evaluated its efficacy with external validation. Methods: We developed the EUS-AI model with ResNeSt50 using EUS images from two hospitals to predict the histopathology of the gastric SELs originating from muscularis propria. The diagnostic performance of the model was also validated using EUS images obtained from four other hospitals. Results: A total of 2,057 images from 367 patients (375 SELs) were chosen to build the models, and 914 images from 106 patients (108 SELs) were chosen for external validation. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the model for differentiating gastrointestinal stromal tumors (GISTs) and non-GISTs in the external validation sets by images were 82.01%, 68.22%, 86.77%, 59.86%, and 78.12%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in the external validation set by tumors were 83.75%, 71.43%, 89.33%, 60.61%, and 80.56%, respectively. The EUS-AI model showed better performance (especially specificity) than some endosonographers.The model helped improve the sensitivity, specificity, and accuracy of certain endosonographers. Conclusions We developed an EUS-AI model to classify gastric SELs originating from muscularis propria into GISTs and non-GISTs with good accuracy. The model may help improve the diagnostic performance of endosonographers. Further work is required to develop a multi-modal EUS-AI system.

Previous studies suggest that the reduction of SMAD3 (mothers against decapentaplegic homolog 3) has a great impact on tumor development, but its exact pathological function remains unclear. In this study, we found that the protein level of SMAD3 was greatly reduced in human-grade IV glioblastoma tissues, in which LAMP2A (lysosome-associated membrane protein type 2A) was significantly up-regulated. LAMP2A is a key rate-limiting protein of chaperone-mediated autophagy (CMA), a lysosome pathway of protein degradation that is activated in glioma. We carefully analyzed the amino-acid sequence of SMAD3 and found that it contained a pentapeptide motif biochemically related to KFERQ, which has been proposed to be a targeting sequence for CMA. In vitro, we confirmed that SMAD3 was degraded in either serum-free or KFERQ motif deleted condition, which was regulated by LAMP2A and interacted with HSC70 (heat shock cognate 71 kDa protein). Using isolated lysosomes, amino-acid residues 75 and 128 of SMAD3 were found to be of importance for this process, which affected the CMA pathway in which SMAD3 was involved. Similarly, down-regulating SMAD3 or up-regulating LAMP2A in cultured glioma cells enhanced their proliferation and invasion. Taken together, these results suggest that excessive activation of CMA regulates glioma cell growth by promoting the degradation of SMAD3. Therefore, targeting the SMAD3-LAMP2A-mediated CMA-lysosome pathway may be a promising approach in anti-cancer therapy.