Objective To specifically extract and analyze nascent proteins synthesized by bone marrow mesenchymal stem cells(BMSCs)after transplantation into ischemic hearts using a technique employing mutant methionyl-tRNA synthetase(MetRSL247G)for nascent protein labeling,in order to explore the potential mechanisms of action in BMSCs post-transplantation.Methods Point mutation at position 274 of the MetRS gene in BMSCs was induced via lentiviral infection to enable azidonorleucine(ANL)-mediated labeling of nascent proteins in BMSCs.The labeling efficiency was verified by means of fluorescent non-canonical amino-acid tagging(FUNCAT).Thirty healthy female C57BL/6J mice(8-10 weeks old)were divided into control and experimental groups,with 15 mice in each group.The acute myocardial infarction model was constructed by ligating the left anterior descending coronary artery in experimental group,while control mice underwent only thoracotomy without coronary ligation.After modeling,both groups received intramyocardial injections of MetRSL247G-modified BMSCs(MetRSL247G-BMSCs)at 3 different sites in the peri-infarct ischemic region.Mice were intraperitoneally injected with ANL every 6 hours for 4 times on postoperative days 0,2,and 6(n=5 for each time point)respectively,euthanized 24 h after the last injection,and cardiac tissues were isolated.The newly synthesized and labeled proteins produced by BMSCs after transplantation into the myocardium of experimental and control groups were collected,using an enrichment technique for ANL-tagged proteins and liquid chromatography-tandem mass spectrometry(LC-MS)analysis.Gene ontology(GO)analysis,Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis,protein-protein interaction(PPI)analysis,and heatmap visualization analysis were performed to identify differentially expressed proteins at the 3 time points and screen key pathways and genes.Results Under fluorescence microscopy,the MetRSL247G lentivirus-infected BMSCs were observed to be labelled with mCherry signals,confirming the successful construction of the MetRSL247G-BMSCs cell line.Green fluorescent signals were detected only in nascent proteins in culture medium containing both MetRSL247G-BMSCs and ANL,validating the sensitivity and specificity of the labeling method.GO analysis revealed that differentially expressed proteins were primarily involved in basic cellular biological processes such as extracellular exosome formation,extracellular matrix organization,and focal adhesion.KEGG and PPI analyses indicated that the differential proteins were mainly involved in complement and coagulation cascade pathway,actin cytoskeleton regulation pathway,and apoptosis pathway.Heatmap analysis showed significantly upregulated expression of anti-apoptosis and cell adhesion-related factors in experimental group on day 1(P＜0.05),upregulated anti-apoptotic factors,pro-apoptotic factors,and cell adhesion-related factors on day 3(P＜0.05),and upregulated anti-apoptotic factors,cell differentiation-related factors,and cell adhesion-related factors on day 7(P＜0.05)compared with control group.Expression of apoptosis-inducing factor 1 was significantly downregulated on days 1 and 7(P＜0.05).On day 3,most differentially expressed proteins,including anti-apoptosis factors(Protein S100-A11,Clusterin,Gelsolin),pro-apoptosis factor(Cathepsin B),cell differentiation-related factor(Transgelin-2),and cell adhesion-related factors(Cofilin-1,Periostin,Fibronectin)were significantly upregulated(P＜0.05).Conclusions The MetRSL247G mutation enables BMSCs to incorporate ANL and synthesize labeled proteins,confirming the feasibility of this nascent protein labeling technique.Nascent proteins of BMSCs in ischemic myocardium primarily contribute to extracellular exosome secretion and extracellular matrix organization.BMSCs may adapt to and respond to ischemic and hypoxic environments by influencing complement and coagulation cascades,activating inflammatory factors,regulating actin cytoskeleton structure,and modulating apoptosis,thereby maintaining the survival of BMSCs.

Objective To investigate the effect of omega-3 polyunsaturated fatty acids(ω-3 PUFA)on chronic atrophic gastritis of rats.Methods A rat model of chronic atrophic gastritis was established by synthetic method.The rats successfully modeled were randomly divided into model group,experimental-L group,experimental-M group,experimental-H group,positive control group.Normal rats were selected as the normal group.There were 9 rats in each group.Experimental-L,-M,-H groups were given 3,6 and 12 mL·kg-1ω-3 PUFA daily,respectively.The positive control group was given 0.24 g·kg-1 vitacoenzyme suspension daily.Normal group and model group were given the same amount of 0.9％NaCl.Each group was given the drug for 12 weeks.Enzyme-linked immunosorbent assay(ELISA)was used to detect serum interleukin-1 β(IL-1β)level.In situ end labeling staining(TUNEL)was used to detecte the apoptosis of gastric mucosa.Relevant kits were used to detect the level of superoxide dismutase(SOD)and malonaldehyde(MDA).Results IL-1 β levels in normal group,model group,experimental-L,-M,-H groups and positive control group were(58.96±8.23),(140.02±19.65),(109.81±14.35),(98.72±12.64),(85.31±11.42)and(77.64±10.23)pg·mL-1,respectively;apoptotic indices were(7.89±1.36)％,(77.12±10.05)％,(42.33±6.87)％,(31.05±5.29)％,(22.76±4.16)％and(16.89±3.05)％,respectively;SOD levels were(398.71±58.24),(170.25±29.81),(249.81±34.26),(268.04±34.11),(322.15±46.36)and(276.42±29.81)U·mg-1,respectively;MDA levels were(3.55±0.87),(11.02±2.15),(8.02±1.50),(6.92±1.23),(5.98±1.27)and(6.67±1.32)U·mg-1,respectively.Compared with normal group,the above indexes were significantly different in model group(all P＜0.01);compared with model group,the above indexes were significantly different in experimental-L,experimental-M,experimental-H groups and positive control group(all P＜0.01).Conclusionω-3 PUFA can ameliorate chronic atrophic gastritis of rats,and the mechanism may be related to the anti-inflammatory,anti-apoptosis and anti-oxidative stress effects of to-3 PUFA.

Objective:To evaluate the effect of low-dose recombinant interleukin-2(rIL-2)therapy on immunocyte subsets and its side effects in children with solid tumor.Methods:A total of 22 children(11 males and 11 females)with solid tumor in our department from December 2012 to November 2017 were selected,with a median age of 9(3-16)years old when starting IL-2 therapy.ALL surgeries and chemotherapy of children had been completed before low-dose rIL-2 therapy,and 17 cases achieved complete remission(CR)and 5 cases achieved partial remission(PR).A low-dose rIL-2 therapy was given 1 month after chemotherapy for 1 year:4 × 105 IU/(m2·d),s.c.for every other day,3 times per week.The immunocyte subsets were detected every 3 months until the end of treatment,meanwhile,disease condition and therapy-related side effects were followed up.Results:After low-dose rIL-2 therapy in 22 children,the absolute values of CD3+T cells,CD3-CD56+natural killer cells,CD3+CD4+helper T cells(Th)and CD3+CD8+cytotoxic T cells were up-regulated remarkably,as well as Th/suppressor T cells(all P＜0.05).While,there were no significant differences in absolute value and proportion of CD4+CD25+CD127-Treg cells during therapy.Among the 17 children who achieved CR before rIL-2 therapy,14 cases continued to maintain CR after therapy,while 3 cases relapsed,and with 2 died after treatment abandonment.The 5 children who achieved PR before low-dose rIL-2 therapy were evaluated CR by PET/CT scan after treatment.In the early stage of low-dose rIL-2 therapy,1 child developed skin rashes at the injection sites,and 2 children ran a slight to mild transient fever.Their symptoms disappeared without any organ damage after symptomatic treatment.Conclusion:Low-dose rIL-2 therapy has good drug tolerance,and changes the distribution of anti-tumor immune-cell subgroup in peripheral blood of children with solid tumor remarkably without up-regulation of absolute value and ratio of Treg cells.

This study was aimed to explore the relation of Treg and invariant natural killer T (iNKT) cell reconstruction with acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children. According to the occurrence or absence of aGVHD, 29 pediatric patients who underwent allo-HSCT were firstly divided into two groups non-aGVHD and aGVHD group,then those patients with aGVHD were divided into steroid effective group and steroid resistant group according to their reaction to the steroid treatment. Flow cytometry was used to detect the frequency of Treg cells and iNKT cells in the peripheral blood of the recipients at different time after allo-HSCT(d 15, d 30, d 60, d 90, the time of aGVHD onset and two weeks after steroid treatment). The result showed that the frequencies of Treg cells and the iNKT/T ratio on day 15 in non-aGVHD group were significantly higher than those in the aGVHD group (P < 0.05). It is concluded that a combined monitoring strategy of Treg and iNKT cell reconstruction early after allo-HSCT may facilitate the diagnosis and treatment of aGVHD in children.
Child ; Child, Preschool ; Early Diagnosis ; Female ; Graft vs Host Disease ; diagnosis ; Hematopoietic Stem Cell Transplantation ; Humans ; Male ; Natural Killer T-Cells ; cytology ; T-Lymphocytes, Regulatory ; cytology ; Transplantation, Homologous