ObjectiveTo investigate the effect and mechanism of Polygonatum neutral polysaccharides from sibiricum （PSP-NP） on colon injury in mice with chronic obstructive pulmonary disease （COPD）. MethodsMale C57BL/6J mice were randomly divided into a control group， a COPD model group， and a PSP-NP group. The COPD model was established using smoke exposure combined with intranasal LPS administration. The PSP-NP group was simultaneously treated daily with 200 mg/kg of PSP-NP via intragastric gavage， while the other groups received an equal volume of saline. HE staining was used to observe the pathological changes in the colon. ELISA was employed to detect the levels of LPS in serum and the expressions of ZO-1， Occludin， IL-6， and TNF-α in colon tissue. UPLC-MS was used to detect the types and contents of bile acids in colonic content， and to screen for differential bile acids. Differential microbial flora were identified using 16S rRNA gene sequencing， and correlation analysis was conducted with differential bile acids. PSP-NP was combined with the differential bile acids cholic acid （CA）， and deoxycholic acid （DCA） in vitro to analyze the binding capacity of PSP-NP for CA and DCA. PSP-NP was applied to NCM460 normal colonic epithelial cells cultured in CA and DCA. Cell migration ability was assessed using the scratch assay， and the mRNA expression levels of inflammatory cytokines TNF-α， IL-6， and NF-κB were measured by RT-qPCR. ResultsPSP-NP effectively improved colonic damage in COPD model mice， enhanced mechanical barrier function， alleviated inflammatory response， and regulated abnormal changes in colonic flora and bile acid metabolism. Correlation analysis further revealed that PSP-NP regulated colonic bile acid metabolism and reduced the redundancy of secondary bile acids by increasing the relative abundance of Bacteroidota， Verrucomicrobiota， Bacteroides， and Akkermansia， while decreasing the relative abundance of Lactobacillus and Bifidobacterium. Notably， in vitro binding assays demonstrated that PSP-NP bound to differential bile acids DCA and CA， with the strongest binding capacity for DCA at 58.2%. In cellular functional studies， DCA inhibited the migration ability of colonic epithelial cells NCM460 and significantly increased the relative mRNA expression levels of inflammatory factors TNF-α， IL-6， and NF-κB. Importantly， co-treatment with PSP-NP significantly ameliorated the impact of DCA on NCM460 cells. ConclusionsPSP-NP may significantly improve colonic damage in COPD model mice. The mechanism may involve the regulation of colonic bile acid metabolism and bile acid profiles through both microbial modulation and direct binding， thereby reducing the damage caused by secondary bile acids such as DCA to colonic epithelial cells.

Objective To map the genome-wide distribution profile of histone H3K27me3 modification in diffuse gastric cancer tissues,identify target genes regulated by H3K27me3,and primarily explore the potential mechanism of its modification reprogramming in the occurrence and development of the tumor.Methods Normal gastric mucosal tissues and diffuse gastric cancer tissues were harvested from the patients who underwent examinations or treatments in the departments of gastroenterology and gastrointestinal surgery of our medical center between 2021 and 2023.There were 14 patients in the normal group(6 males and 8 females,average age of 46 years)and 14 patients in the gastric cancer group(8 males and 6 females,average age of 63 years).Cleavage under target and tagmentation(CUT&Tag)technology was employed to capture genomic regions modified by H3K27me3,and analyze the reprogramming characteristics of these modifications.RNA sequencing data,data from high-throughput chromosome conformation capture(Hi-C)technology,and publicly available single-cell data were integrated to investigate the target genes regulated by the reprogramming of H3K27me3 modifications in diffuse gastric cancer cells.Results The quality of the CUT&Tag and RNA sequencing data met the standards required for subsequent analysis.Histone H3K27me3 modifications in normal gastric mucosa and diffuse gastric cancer tissues were primarily distributed in distal intergenic regions and intronic regions.In gastric cancer tissues,compared to normal tissues,there was significant reprogramming of H3K27me3 modifications,characterized by a marked reduction in overall H3K27me3 signal intensity.The loss of 2 912 H3K27me3 signal peaks might lead to the up-regulation of 822 tumor-associated genes.Among them,56 genes displayed the most significant up-regulation(fold change in signal intensity≥2,P<0.05),with notable enrichment in the mammalian target of rapamycin complex 1(mTORC1)signaling pathway.Specifically,the methionine transporter SLC7A5 and the cystine transporter SLC7A11 were found to have the highest expression levels in gastric cancer tissues.Single-cell data revealed that the abnormal overexpression of SLC7A11 in diffuse gastric cancer was primarily observed in tumor epithelial cells.Further validation using public data and immunohistochemical experiments confirmed the elevated expression of SLC7A11 in diffuse gastric cancer,which is associated with poor prognosis in gastric cancer patients.Conclusion The reprogramming of histone H3K27me3 modification is an important epigenetic characteristic in diffuse gastric cancer.Loss of H3K27me3 signal peaks may up-regulate the expression of SLC7A11 in diffuse gastric cancer cells,and thereby promote tumor progression.

Objective To draw the genome-wide distribution and remodeling characteristics of H3K27me3 silencers in signet-ring cell carcinoma of the stomach(SRCC)through epigenetic sequencing technology,and to investigate their roles in transcriptional regulation in order to elucidate the regulatory mechanism of SRCC malignant progression.Methods The study was conducted on 35 gastric samples obtained by gastroendoscopic biopsy(15 normal and 20 SRCC tissues)from Department of Gastroenterology of Army Medical Center of PLA between January 2021 and December 2023.Multi-omics analyses,including assay for transposase-accessible chromatin with high-throughput sequencing(ATAC-seq),cleavage under targets and tagmentation(CUT&Tag)and transcriptome sequencing(RNA-seq),were performed to identify chromatin accessibility,H3K27me3 silencer regions,and transcriptional changes,with aid of Illumina NovaSeq 6000.H3K27me3 related differentially expressed genes(|Log2FC|>1,FDR<0.05)were screened using DESeq2.Gene Ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis were employed to analyze the enrichment function,and Homer was employed to identify transcription factor motifs.A regulatory network was constructed using Cytoscape,and then validated using immunohistochemistry to explore its regulatory mechanism.Results H3K27me3 silencers were primarily located in distal intergenic regions(37.06%)in SRCC.Compared with the normal tissues,SRCC showed a significant reduction in H3K27me3 silencer signals(95%CI:1.34～2.30,P=0.007)with 6 257 lost sites(FDR<0.01).Integrating CUT&Tag and RNA-seq revealed 380 up-regulated immune-related genes,particularly in T cell receptor signaling(OR=4.2,95%CI:2.8～6.3,P=0.002).Immunohistochemistry confirmed elevated expression of transcription factor EHF(P<0.05).Conclusion There is the remodeling of H3K27me3 silencers in SRCC,and EHF may potentially play a crucial role in the SRCC malignant progression.

This paper systematically reviews the phased development history of spacesuit technology across various nations,analyzes its core technologies and breakthroughs,points out the limitations of current spacesuit technology,and explores future directions for spacesuit development in response to deep-space exploration and commercialization demands.It clarifies that spacesuits are transitioning from passive protective gear to intelligent operational platforms,requiring interdisciplinary innovations to overcome key challenges such as lightweight design,adaptive systems,high reliability,and efficient human-machine interaction.

Ripple structure is widely used in space suits,and the predicted trajectory motion is realized according to its large deformation behavior.Due to the complexity of irregular bellows structure,the existing researches are mostly based on the display dynamic method,and lack the systematic analysis of geometric nonlinearity and the effect of shell section thickness under the framework of statics.This study combines statics and arc length method(Riks),introduces linear buckling mode defects,and analyzes the ultimate bending behavior of irregular bellows with different shell thicknesses.It is concluded that the thick-shell model exhibits higher apparent deformation tolerance due to geometric softening effect,and the contact force distribution between ripples can be accurately extracted by static analysis,which provides a basis for the inversion of external force loads.The deformation mode of bellows after introducing defects based on statics-Riks is proposed,and the control mechanism of shell section thickness on deformation path is revealed.

OBJECTIVE To investigate the regulatory effects of couplet medicinals of Atractylodes macrocephala-Aucklandia lappa on gut microbiota and short-chain fatty acids （SCFAs） in the diarrhea-type irritable bowel syndrome （IBS-D） rats with spleen deficiency. METHODS The IBS-D rat model with spleen deficiency was induced by intragastric administration of Senna alexandrina combined with restraint stimulation. The model rats were divided into model group， positive control group （pinaverium bromide 1.5 mg/kg）， A. macrocephala-A. lappa low-dose， medium-dose and high-dose groups （0.7， 1.4， 2.8 g/kg）， with 6 rats in each group. Another 6 healthy rats were taken as the blank control group. The blank control group and the model group were given normal saline intragastrically， and other groups were given relevant drug liquid intragastrically， once a day， for consecutive 14 days. The general characteristics of rats and fecal water content were observed， and intestinal sensitivity [evaluating by abdominal wall withdrawal reflex （AWR） threshold] and the intestinal propulsion rate were determined. The serum levels of 5- hydroxytryptamine（5-HT）and SP were detected， and the pathological changes of colon tissue were observed； the protein expressions of 5-HT-3 receptor（5-HT3R）， 5-HT4R and 5-HT transporter（SERT） in colon tissue of rats were detected. 16S rRNA sequencing was performed for the feces of rats in blank control group， model group and A. macrocephala-A. lappa high-dose group； the contents of acetic acid， propionic acid and butyric acid in the feces of the rats were determined. RESULTS Compared with the model group， the body weight after 7 and 14 days of medication， fecal water content， AWR threshold， and the protein expressions of 5-HT4R and SERT in colon tissue were increased significantly in the A. macrocephala-A. lappa medium-dose and high-dose groups （P＜0.05 or P＜0.01）； serum contents of 5-HT and SP， intestinal propulsion rate （except for A. macrocephala-A. lappa medium-dose group）， the protein expression of 5-HT3R in colon tissue were decreased significantly （P＜0.01）； diarrhea relief， mental state recovery， and partially recovery of the structure of colon tissue were all found； moreover， the diversity and species number of gut microbiota were reduced in A. macrocephala-A. lappa high-dose group and the content of butyric acid in fecal samples was significantly reduced （P＜0.05）. CONCLUSIONS The compatibility of A. macrocephala and A. lappa can improve intestinal motility and sensitivity of IBS-D model rats with spleen deficiency， and alleviate diarrhea. This may be related to improving changes in intestinal microbiota structure， reducing 5-HT expression and butyric acid content， and increasing 5-HT4R and SERT expression.

BACKGROUND:The formation of Lewy bodies due to abnormal α-synuclein aggregation is a characteristic pathological change in Parkinson's disease.In recent years,several studies have revealed that the formation of α-synuclein aggregates is closely related to its post-translational modifications.The modification of α-synuclein such as phosphorylation,nitration,acetylation,and ubiquitination has attracted extensive attention in the pathogenesis and progression of Parkinson's disease. OBJECTIVE:To review the research progress in the effect of modification types and sites of α-synuclein on the characteristic pathological formation and progression of Parkinson's disease. METHODS:PubMed and CNKI databases were searched by the first author with the key words of"α-synuclein,Parkinson's disease,phosphorylation,acetylation,ubiquitination,nitration"in English and Chinese respectively to collect and sort out the literature related to abnormal modification of α-synuclein in recent years.Finally,61 articles were included for further review. RESULTS AND CONCLUSION:Abnormal modification of α-synuclein is closely related to its protein structure and its positive and negative charges.Its amino terminus is positively charged and prone to ubiquitination and acetylation modifications.The central hydrophobic region is prone to forming β-pleated sheet due to its hydrophobic property.The carboxyl terminus is negatively charged,which is the main phosphorylation modification region.Phosphorylation modification sites promote phosphorylation modification and are closely related to α-synuclein aggregation,while protein kinases can target the activation of translational modifications,which may help to promote or inhibit aggregate formation.The degradation pathway of α-synuclein mainly plays a role in removing pathological proteins.Various kinase catalysts contribute to impaired protein ubiquitination modifications that lead to abnormal protein accumulation,thereby exacerbating neurodegeneration.The amino-terminal acetylation of α-synuclein improves the shuttle ability of the protein to the cell membrane and slows down the protein aggregation,which may be the protection target of nerve cells.However,the acetylation modification of the mutant protein produces the opposite effect.The protein nitration modification is mainly related to oxidative stress.The aggregation tendency of the protein modified by nitration is enhanced under the action of reactive oxygen species.Different post-translational modifications have different effects.Therefore,elucidating the main mechanisms of their post-translational modifications and inhibiting the post-translational modifications that contribute to protein aggregation may provide a reference for new targets for early diagnosis and treatment of Parkinson's disease.

BACKGROUND:C2 ceramide reduces the formation of Alpha-Synuclein(α-Syn)oligomers as the protein phosphatase 2A agonist,which has an important regulatory effect on cell aging in the central nervous system. OBJECTIVE:To investigate the protective mechanism of C2 ceramide on dopaminergic neurons. METHODS:Twenty-five C57BL/6 mice were randomly divided into control group,model group,C2 ceramide low-,medium-and high-dose groups(n=5 per group).Except for the control group,a mouse model of Parkinson's disease was established by injecting mutant A53T α-Syn oligomers into the left striatum in the other groups.On the 30th day after the striatal injection,three C2 ceramide groups were intragastrically administered with C2 ceramide(1,5,10 μg/g)dissolved in saline at one time,while the control and model groups were administered with the same amount of saline within 30-90 days after modeling,for a total of 60 days.Behavioral changes in each group of mice were observed during this period.On the 90th day after striatal injection,mouse brain tissue was extracted by perfusion under anesthesia,and the changes of dopaminergic neurons in the midbrain substantia nigra were analyzed by immunohistochemical staining.The levels of α-Syn oligomerization and phosphorylation in the midbrain of mice were detected by ELISA,and the changes of enzyme activities related to α-Syn phosphorylation were analyzed. RESULTS AND CONCLUSION:C2 ceramide had an ameliorating effect on Parkinson's disease-like dyskinesia in mice caused by the striatal injection of mutant A53T α-Syn oligomers.High-dose C2 ceramide showed better effects on dyskinesia in mice with Parkinson's disease(P<0.01).The mutant A53T α-Syn oligomers significantly reduced the number of dopaminergic neurons in the substantia nigra of mice(P<0.01),while the number of dopaminergic neurons in the substantia nigra increased significantly in the C2 ceramide high-dose group(P<0.01).The levels of α-Syn oligomers and phosphorylated α-Syn in the brain were significantly reduced in the C2 ceramide high-dose group compared with the model group(P<0.01),while the level of ceramide was increased(P<0.05)and the activity of protein phosphatase 2A was significantly upregulated(P<0.01).To conclude,C2 ceramide can attenuate the neurotoxic effects induced by oligomerized α-Syn by the phosphorylation modification environment of α-Syn in mouse midbrain tissue and protect against the reduction in the number of nigrostriatal dopaminergic neurons in mice,thereby reducing the degree of dyskinesia in Parkinson's disease.

Objective To investigate the effect of the mediator of DNA damage check point protein 1(MDC1)on proliferation,migration,invasion,cell cycle and cell apoptosis in cholangiocarcinoma(CCA)and the potential molecular mechanism.Methods The small interfering RNA(siRNA)specifically targeting MDC1 was used to transiently knock down MDC1.Recombined plasmid containing MDC1 was transiently transfected into RBE and Huh28 cells for over-expression of MDC1.Real time quantitative PCR(qPCR)and Western blotting were adopted to verify the effectiveness of MDC1 knockdown or overexpression.The proliferation of CCA cells was measured via CCK-8 and cell colony formation assays.Transwell and Invasion assays were used to detect cell migration and invasion while flow cytometry assays were employed to detect cell cycle and apoptosis.Gene set enrichment analysis(GSEA)was conducted to investigate the pathways which were significantly associated with MDC1,and the expression of p53 downstream protein was verified by Western blotting assay.Co-immunoprecipitation(Co-IP)assays were used to verify the interactions between MDC1 and p53.Flow cytometry and Western blotting assays were performed to find out whether MDC1 promoted cell cycle and cell apoptosis through p53 pathway.Based on The Cancer Genome Altas(TCGA)database,the difference in MDC1 expression levels between CCA and normal tissues was analyzed,and the correlations between the MDC1 expression levels and the clinical prognosis of CCA patients were investigated.Results Knockdown of MDC1 in RBE and Huh28 cells significantly inhibited cells proliferation,migration and invasion,significantly decreased the proportion of cells in S phase,and significantly increased the proportion of cells in G0/G1 phase and apoptosis rate while overexpression of MDC1 could significantly promote cell proliferation,migration and invasion,significantly increase the proportion of cells in S phase,and significantly decrease the proportion of cells in G0/G1 phase and apoptosis rate.It was found that MDC1 interacted with p53 in RBE and Huh28 cells,and MDC1 significantly down-regulated the expressions of p53,p-p53(Ser-15),BAX,PUMA and p21,but significantly up-regulated the expression of Bcl-2,which in turn promoted the tumorigenesis of CCA.MDC1 was up-regulated in CCA tissues compared to the normal tissues,and the high expressions of MDC1 were significantly associated with poor clinical outcomes of CCA patients.Conclusion MDC1 promotes the development of CCA by suppressing the p53 pathway,and MDC1 may be a candidate marker for the poor prognosis in CCA.

Dexmedetomidine displays multiple mechanisms of neuroprotection in ameliorating ischemic brain injury. In this study, we explored the beneficial effects of dexmedetomidine on blood-brain barrier (BBB) integrity and neuroinflammation in cerebral ischemia/reperfusion injury. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 1.5 h and reperfusion for 24 h to establish a rat model of cerebral ischemia/reperfusion injury. Dexmedetomidine (9 µg/kg) was administered to rats 30 min after MCAO through intravenous injection, and SB203580 (a p38 MAPK inhibitor, 200 µg/kg) was injected intraperitoneally 30 min before MCAO. Brain damages were evaluated by 2,3,5-triphenyltetrazolium chloride staining, hematoxylin-eosin staining, Nissl staining, and brain water content assessment. BBB permeability was examined by Evans blue staining. Expression levels of claudin-5, zonula occludens-1, occludin, and matrix metalloproteinase-9 (MMP-9) as well as M1/M2 phenotypes-associated markers were assessed using immunofluorescence, RT-qPCR, Western blotting, and gelatin zymography. Enzyme-linked immunosorbent assay was used to examine inflammatory cytokine levels. We found that dexmedetomidine or SB203580 attenuated infarct volume, brain edema, BBB permeability, and neuroinflammation, and promoted M2 microglial polarization after cerebral ischemia/reperfusion injury. Increased MMP-9 activity by ischemia/reperfusion injury was inhibited by dexmedetomidine or SB203580. Dexmedetomidine inhibited the activation of the ERK, JNK, and p38 MAPK pathways. Moreover, activation of JNK or p38 MAPK reversed the protective effects of dexmedetomidine against ischemic brain injury. Overall, dexmedetomidine ameliorated brain injury by alleviating BBB permeability and promoting M2 polarization in experimental cerebral ischemia/reperfusion injury model by inhibiting the activation of JNK and p38 MAPK pathways.