ObjectiveBola-like short peptides exhibit novel self-assembly properties due to the formation of peptide dimers via hydrogen bonding interactions between their C-terminals. In this configuration, hydrophilic amino acids are distributed at both terminals, making these peptides behave similarly to Bola peptides. The electrostatic repulsive interactions arising from the hydrophilic amino acids at each terminal can be neutralized, thereby greatly promoting the lateral association of β-sheets. Consequently, assemblies with significantly larger widths are typically the dominant nanostructures for Bola-like peptides. To investigate the effect of hydrophilic amino acids on the self-assembly behavior of Bola-like peptides, the peptides Ac-RI₃-CONH₂ and Ac-HI₃-CONH₂ were designed and synthesized using the Bola-like peptide Ac-KI₃-CONH₂ as a template. Their self-assembly behavior was systematically examined. MethodsAtomic force microscopy (AFM) and transmission electron microscopy (TEM) were employed to characterize the morphology and size of the assemblies. The secondary structures of the assemblies were analyzed using circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy. Small-angle neutron scattering (SANS) was used to obtain detailed structural information at a short-length scale. Based on these experimental results, the effects of hydrophilic amino acids on the self-assembly behavior of Bola-like short peptides were systematically analyzed, and the underlying formation mechanism was explored. ResultsThe aggregation process primarily involved three steps. First, peptide dimers were formed through hydrogen bonding interactions between their C-terminals. Within these dimers, the hydrophilic amino acids K, R, and H were positioned at both terminals, enabling the peptides to self-assemble in a manner similar to Bola peptides. Next, β-sheets were formed via hydrogen bonding interactions along the peptide backbone. Finally, self-assemblies were generated through the lateral association of β-sheets. The results demonstrated that both Ac-KI₃-CONH₂ and Ac-RI₃-CONH₂ could self-assemble into double-layer nanotubes with diameters of approximately 200 nm. These nanotubes were formed by the edge fusion of helical ribbons, which initially emerged from twisted ribbons. Notably, the primary assemblies of these peptides exhibited opposite chirality: nanofibers formed by Ac-KI₃-CONH₂ displayed left-handed chirality, whereas those formed by Ac-RI₃-CONH₂ exhibited right-handed chirality. This reversal in torsional direction was primarily attributed to the different abilities of K and R to form hydrogen bonds with water. In contrast, Ac-HI₃-CONH₂ formed narrower twisted ribbons with a significantly reduced width of approximately 30 nm, which was attributed to the strong steric hindrance caused by the imidazole rings. The multilayer height of these ribbons was mainly due to the unique structure of the imidazole rings, which can function as both hydrogen bond donors and acceptors, thereby promoting aggregate growth in the vertical direction. ConclusionThe final morphology of the self-assemblies resulted from a delicate balance of various non-covalent interactions. By altering the types of hydrophilic amino acid residues in Bola-like short peptides, the relative strength of non-covalent interactions that drive assembly formation can be effectively regulated, allowing precise control over the morphology and chirality of the assemblies. This study provides a simple and effective approach for constructing diverse self-assemblies and lays a theoretical foundation for the development of functional biomaterials.

Major depressive disorder(MDD)is a prevalent con-dition associated with substantial impairment and low remission rates.Traditional antidepressants demonstrate delayed effects,low cure rate,and inadequate therapeutic effectiveness for man-aging treatment-resistant depression(TRD).Several studies have shown that ketamine,a non-selective N-methyl-D-aspartate receptor(NMDAR)antagonist,can produce rapid and sustained antidepressant effects.Ketamine has demonstrated efficacy for reducing suicidality in TRD patients.However,the pharmaco-logical mechanism for ketamine's antidepressant effects remains incompletely understood.Previous research suggests that the an-tidepressant effects of ketamine may involve the monoaminergic,glutamatergic and dopaminergic systems.This paper provides an overview of the pharmacological mechanism for ketamine's anti-depressant effects and discuss the potential directions for future research.

Aim To investigate the role of ferrostatin-1(Fer-1)in adriamycin(ADR)induced podocyte inju-ry.Methods Western blot and RT-qPCR were used to detect the expression of the ferroptosis signaling pathway and podocyte injury-related proteins in podo-cytes treated with ADR and Fer-1.The therapeutic effect of Fer-1 on podocytes was screened by CCK-8;malondialdehyde(MDA),glutathione(GSH)and Fe2+kit were used to evaluate the lipid peroxidation level of podocytes.A mouse model of ADR nephropa-thy was constructed in vivo,and the expression of fer-roptosis related proteins in mouse glomerular podocytes was detected by Western blot and RT-qPCR.The fer-roptosis level of kidney was evaluated by immunohisto-chemistry staining of 4-HNE.Results The expression level of ACSL4,a marker related to ferroptosis,was significantly up-regulated.GPX4 and SLC7A11 were significantly down-regulated in podocytes under ADR stimulation.Compared with the ADR group,Fer-1 in-tervention could partially restore the anomalous change of ferroptosis related protein and improve the expression level of podocellular damage protein desmin.The re-sults of MDA,GSH and Fe2+showed that Fer-1 could improve the lipid peroxidation level of podocytes.The expression level of ACSL4 was significantly up-regula-ted and GPX4 and SLC7A11 were significantly up-reg-ulated in the ADR model group.IHC staining of 4-HNE increased in ADR model group.Conclusions Adriamycin promotes podocyte injury by induced ferrop-tosis,and inhibiting ferroptosis may be a potential strat-egy to prevent the progression of ADR nephropathy.

Glutamate,norepinephrine,and their receptors com-prise the glutamatergic and norepinephrine systems,which mu-tually affect each other and play essential roles in mediating vari-ous neuropsychiatric diseases.This paper reviews the functions of N-methyl-D-aspartate receptor(NMDA-R)and α2-adrenergic receptor(α2-AR)and their functional crosstalk at the molecular level in brain in common neuropsychiatric diseases,which would benefit our understanding of neuropathophysiology of psychiatric diseases,drug development and optimization of clinical neuro-psychopharmacology.

Aim To explore the effects of sirolimus on the growth and development of motor,vascular,nerv-ous,and immune systems through zebrafish models.Methods After 3 hours of fertilization of zebrafish embryos,different concentrations of sirolimus were add-ed to the growth environment,and the growth and de-velopment of the embryos was recorded.Transgenic ze-brafish models labeled with blood vessels,nerves or im-mune cells were used to compare the drug effects on the growth and development of those systems.Results At the concentration of 0.5 μmol·L-1,the hatching rate and the body length(P＜0.01)were significantly smaller than those of the control group,and movement was also significantly slowed down.Meanwhile,the length of axons of the nervous system,the development of intersegmental vessels,and the growth of immune cells were significantly delayed by drug treatment.But when the concentration was below 0.1 μmol·L-1,there was no statistically difference between the control group and the sirolimus group.Conclusions When the concentration of sirolimus exceeds a certain level,it can significantly slow down the growth and development of movement,blood vessels,nervous system and im-mune system of zebrafish.Therefore,in clinical prac-tice,it is important to monitor the blood concentration of sirolimus in children on time.

Objective To investigate the risk factors for delayed union of extra-articular fractures of the middle and lower third of the tibia treated by locking plate.Methods Total of 135 patients of extra-articular fractures of the middle and lower third of the tibia from January 2013 to December 2018 were retrospectively analyzed,including 85 males and 50 females,ranged from 19 to 80 years old.All cases were treated with locking plates.The patients were divided into union group and delayed union group ac-cording to the condition of fracture union.The risk factors of delayed healing were determined by univariate analysis of 14 factors that might affect fracture healing first,then the factors with significance were analyzed by binary Logistic regression.Results There were 13 patients of delayed union,and the rate of delayed union was 9.63％.Univariate analysis showed that delayed union was associated with age,smoking,reduction method,anemia and time of preoperative preparation.Regression analysis showed thatage[OR=0.849,95％CI(0.755,0.954),P=0.006],smoking[OR=0.020,95％CI(0.002,0.193),P=0.001],reduction method[OR=23.924,95％CI(2.210,258.943),P=0.009],anemia[OR=0.016,95％CI(0.001,0.289),P=0.005]were the con-tributory factors for delayed union.Conclusion Young age,smoking,closed reduction and anemia are the risk factors for de-layed union of extra-articular fractures of the middle and lower third of the tibia treated by locking plate.

A prokaryotic expression vector for the mutant diphtheria toxin CRM197 was constructed and expressed in Esch-erichia coli cells.Anti-CRM197 antibody concentrations were detected in serum samples of healthy volunteers.The crm 197 gene was codon-optimized in E.coli and cloned into the plasmid pET28a(+)under optimized expression conditions.CRM197 was purified using Ni-NTA spin columns and ion exchange chromatography,and confirmed by western blot analysis.The puri-fied CRM197 was used to detect specific anti-CRM197 antibody levels in serum samples of different age groups.The results showed that soluble codon-optimized CRM197 was successfully expressed under optimized expression conditions.The purity of CRM197 was more than 95％,as determined with Ni-NTA spin columns and ion exchange chromatography,consistent with the single specific bands obtained by western blot analysis and detection of serum levels of the anti-CRM197 antibody.Collec-tively,these results confirmed that the proposed expression strategy achieved high-yield production of soluble CRM197,al-though high levels in human serum may affect evaluation of immune interactions with glycan-CRM197 conjugates for applica-tion as a diagnostic antigen.The diphtheria mutant toxin CRM197 is used in many conjugate vaccines.The synthetic crm 197 gene with codon optimization in pET28a was transformed into E.coli Origami B(DE3)cells.CRM197 was induced by isopro-pyl β-d-1-thiogalactopyranoside and high level accumulation of soluble CRM197 was purified using Ni-NTA spin columns and ion exchange chromatography.The purity of the final prepara-tion reached 95％.CRM197 was used to detect the concentra-tions of the anti-CRM197 antibody in serum samples of healthy volunteers of different ages.The proposed expression strategy yielded high production of CRM197,which could interfere with evaluations of induced immune interactions by glycan-CRM197 conjugates and prohibit application as a diagnostic antigen.

The molecular epidemiological characteristics of 1,4,[5],12:i:-Salmonella in Jiangsu Province were analyzed through whole genome sequencing(WGS).The distribution characteristics of related genes were obtained on the basis of anno-tated drug-resistant genes and plasmid types in the whole genome.Analysis of the molecular epidemiological characteristics of strains with cgMLST revealed possible modes of transmission of quinolone resistance in 1,4,[5],12:i:-Salmonella.Eleven cat-egories of antibiotic resistance genes(ARGs)were annotated among the fluoroquinolone-resistant strains.The detection rate of aminoglycoside ARGs was highest(100％).Twelve quinolone-resistant strains(92.3％)carried the IncHI2/IncHI2A plasmid type.PMQR gene analysis of various strains indicated that the strains from the United States and Europe carried six types of PMQR genes,and the detection rate of qnrB19 was highest.The Jiangsu strains carried three PMQR gene types,and the de-tection rate of aac(6')-Ib-cr was highest(11.84％).Analysis of cgMLST loci from different countries/regions revealed three main epidemic clusters.Some isolates from Jiangsu province might have the same evolutionary origin as some isolates from Eu-rope and the United States,and national/regional differences were observed in the PMQR gene carriage level.

Objective:To explore the role of bone marrow mesenchymal stem cells(BMSC),an essential element of the bone marrow microenvironment,in multidrug resistance(MDR)of K562 cells,as well as the reversal effect of tetrandrine(TET)on BMSC-mediated MDR and its potential mechanism.Methods:A mixed co-culture system and a transwell co-culture system for BMSC and K562 cells were established,and the cells were divided into different groups and treated with daunorubicin(DNR)alone or combined with TET and DNR.The CCK-8 assay was used to detect the proliferation of K562 cells in each group,and the cell inhibition rate was calculated.Cytometric bead array(CBA)was used to detect the expression levels of IFN,IL-2,IL-6 and IL-10 in the supernatant of different groups.RT-qPCR and Western blot were used to detected the expression of STAT3 at mRNA and protein levels,respectively.Results:Compared with K562+DNR group,the inhibition rate of DNR on K562 cell proliferation in K562+BMSC+DNR group was significantly decreased(P＜0.05),while the levels of IL-6 in the culture supernatant and phosphorylated STAT3 in K562 cells were significantly increased(P＜0.05).Compared with K562+BMSC+DNR group,the inhibition rate of DNR on K562 cell proliferation in K562+BMSC+DNR+TET group was significantly increased(P＜0.05),while the level of IL-6 and phosphorylated STAT3 was significantly decreased(P＜0.05).Conclusion:BMSC can promote the drug resistance of leukemia cells,and TET may reverse the BMSC-mediated drug resistance via inhibiting IL-6/STAT3 signaling pathway.

Objective:To investigate the effect of GRIM-19 on the resistance of carcinoma cells to the chemotherapeutic agent docetaxel in the treatment of PCa.Methods:Using siRNA technology to interfere with the gene expression in PCa cells,we estab-lished a model of GRIM-19 overexpression/knockdown in PCa cells.We investigated the effect of different expression levels of GRIM-19 on docetaxel-induced death of the PCa cells by qPCR,Western blot and flow cytometry,and assessed the value of GRIM-19 in re-ducing the chemotherapy-resistance of PCa cells.Results:GRIM-19 was down-regulated in PCa tissues and cells.Knockout of GRIM-19 significantly decreased the expression of siGRIM19 in the PC-3 and LNCaP cells,and reduced their death rate when treated with docetaxel compared with the control group.The expressions of GRIM-19 mRNA and protein were remarkably upregulated after transfection with GRIM-19,and the overexpressed GRIM-19 promoted the death of the PC-3 and LNCaP cells treated with docetaxel in a dose-dependent manner.Flow cytometry analysis showed a lower apoptosis rate of PC-3-R cells than that of PC-3 cells at different time points of docetaxel-induction at different doses.Conclusion:GRIM-19 is a PCa suppressor gene with a significant facilitating effect on the apoptosis of PCa cells,and the overexpression of GRIM-19 promotes docetaxel-induced PCa cell death and improves the sensitivity of chemotherapy.