OBJECTIVE: To investigate the effects and underlying mechanism of ionizing radiation on the adipogenic of mesenchymal stem cells (MSCs). METHODS: Mouse MSCs were cultured in vitro and treated with 2 Gy and 6 Gy radiation with ⁶⁰Co, and the radiation dose rate was 0.98 Gy/min. Bulk RNA-seq was performed on control and irradiated MSCs. The changes of adipogenic differentiation and oxidative stress pathways of MSC were revealed by bioinformatics analysis. Oil Red O staining was used to detect the adipogenic differentiation ability of MSCs in vitro, and real-time fluorescence quantitative PCR (qPCR) was used to detect the expression differences of key regulatory factors Cebpa, Lpl and Pparg after radiation treatment. At the same time, qPCR and Western blot were used to detect the effect of inhibition of Nrf2, a key factor of antioxidant stress pathway, on the expression of key regulatory factors of adipogenesis. Moreover, the species conservation of the irradiation response of human bone marrow MSCs and mouse MSC was determined by qPCR. RESULTS: Bulk RNA-seq suggested that ionizing radiation promotes adipogenic differentiation of MSCs and up-regulation of oxidative stress-related genes and pathways. The results of Oil Red O staining and qPCR showed that ionizing radiation promoted the adipogenesis of MSCs, with high expression of Cebpa, Lpl and Pparg, as well as oxidative stress-related gene Nrf2. Nrf2 pathway inhibitors could further enhance the adipogenesis of MSCs in bone marrow after radiation. Notably, the similar regulation of oxidative pathways and enhanced adipogenesis post irradiation were observed in human bone marrow MSCs. In addition, irradiation exposure led to up-regulated mRNA expression of interleukin-6 and down-regulated mRNA expression of colony stimulating factor 2 in human bone marrow MSCs. CONCLUSION Ionizing radiation promotes adipogenesis of MSCs in mice, and oxidative stress pathway participates in this effect, blocking Nrf2 further promotes the adipogenesis of MSCs. Additionally, irradiation activates oxidative pathways and promotes adipogenic differentiation of human bone marrow MSCs.
Mesenchymal Stem Cells/cytology* ; Oxidative Stress/radiation effects* ; Animals ; Adipogenesis/radiation effects* ; Mice ; Radiation, Ionizing ; Cell Differentiation/radiation effects* ; Humans ; NF-E2-Related Factor 2/metabolism* ; PPAR gamma ; Cells, Cultured

OBJECTIVE: To establish an in vitro cell model simulating acute graft-versus-host disease (aGVHD) bone marrow microenvironment injury with the advantage of mouse serum of aGVHD model and explore the effect of serum of aGVHD mouse on the adipogenic differentiation ability of mesenchymal stem cells (MSCs). METHODS: The 6-8-week-old C57BL/6N female mice and BALB/c female mice were used as the donor and recipient mice of the aGVHD model, respectively. Bone marrow transplantation (BMT) mouse model (n=20) was established by being injected with bone marrow cells (1×10⁷ per mouse) from donor mice within 4-6 hours after receiving a lethal dose (8.0 Gy, 72.76 cGy/min) of γ ray general irradiation. A mouse model of aGVHD (n=20) was established by infusing a total of 0.4 ml of a mixture of donor mouse-derived bone marrow cells (1×10⁷ per mouse) and spleen lymphocytes (2×10⁶ per mouse). The blood was removed from the eyeballs and the mouse serum was aspirated on the 7^th day after modeling. Bone marrow-derived MSCs were isolated from 1-week-old C57BL/6N male mice and incubated with 2%, 5% and 10% BMT mouse serum and aGVHD mouse serum in the medium, respectively. The effect of serum in the two groups on the in vitro adipogenic differentiation ability of mouse MSCs was detected by Oil Red O staining. The expression levels of related proteins PPARγ and CEBPα were detected by Western blot. The expression differences of key adipogenic transcription factors including PPARγ, CEBPα, FABP4 and LPL were determined by real-time quantitative PCR (RT-qPCR). RESULTS: An in vitro cell model simulating the damage of bone marrow microenvironment in mice with aGVHD was successfully established. Oil Red O staining showed that the number of orange-red fatty droplets was significantly reduced and the adipogenic differentiation ability of MSC was impaired at aGVHD serum concentration of 10% compared with BMT serum. Western blot experiments showed that adipogenesis-related proteins PPARγ and CEBPα expressed in MSCs were down-regulated. Further RT-qPCR assay showed that the production of PPARγ, CEBPα, FABP4 and LPL, the key transcription factors for adipogenic differentiation of MSC, were significantly reduced. CONCLUSION The adipogenic differentiation capacity of MSCs is inhibited by aGVHD mouse serum.
Animals ; Mesenchymal Stem Cells/cytology* ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Adipogenesis ; Female ; Cell Differentiation ; Graft vs Host Disease/blood* ; Bone Marrow Cells/cytology* ; PPAR gamma/metabolism* ; Disease Models, Animal ; CCAAT-Enhancer-Binding Protein-alpha/metabolism*

OBJECTIVE: To prepare clinical-grade human umbilical cord-derived mesenchymal stem cells (hUC-MSC) with high expression of hematopoietic supporting factors and evaluate their stem cell characteristics. METHODS: Fetal umbilical cord tissues were collected from healthy postpartum women during full-term cesarean section. Wharton's jelly was mechanically separated and hUC-MSCs were obtained by explant culture method and enzyme digestion method in an animal serum-free culture system with addition of human platelet lysate. The phenotypic characteristics of hUC-MSCs obtained by two methods were detected by flow cytometry. The differences in proliferation ability between the two groups of hUC-MSCs were identified through CCK-8 assay and colony forming unit-fibroblast (CFU-F) assay. The differences in multilineage differentiation potential between the two groups of hUC-MSCs were identified through induction of adipogenic, osteogenic, and chondrogenic differentiation. The mRNA expression levels of hematopoietic supporting factors such as SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in the two groups of hUC-MSCs were identified by real-time fluorescence quantiative PCR(RT-qPCR). RESULTS: The results of flow cytometry showed that hUC-MSCs obtained by the two methods both expressed high levels of CD73, CD90 and CD105, while lowly expressed CD31, CD45 and HLA-DR. The results of CCK-8 and CFU-F assay showed that the proliferation ability of hUC-MSCs obtained by explant culture method was better than those obtained by enzyme digestion method. The results of the triple lineage differentiation experiment showed that there was no significant difference in multilineage differentiation potential between the two grous of hUC-MSCs. The results of RT-qPCR showed that the mRNA expression levels of hematopoietic supporting factors SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in hUC-MSCs obtained by explant cultrue method were higher than those obtained by enzyme digestion method. CONCLUSION Clinical-grade hUC-MSCs with high expression levels of hematopoietic supporting factors were successfully cultured in an animal serum-free culture system.
Humans ; Mesenchymal Stem Cells/metabolism* ; Umbilical Cord/cytology* ; Cell Differentiation ; Female ; Cell Proliferation ; Cells, Cultured ; Chemokine CXCL12/metabolism* ; Angiopoietin-1/metabolism* ; Vascular Cell Adhesion Molecule-1/metabolism* ; Stem Cell Factor/metabolism* ; Flow Cytometry ; Pregnancy

The scientific rigor and efficacy of methodologies employed in drafting emergency health systems guidance documents （HSGs） are paramount in guaranteeing the quality， reliability， and applicability of HSGs. According to the Appraisal of Guidelines for Research and Evaluation- Health Systems （AGREE-HS）， we demonstratively assessed both global coronavirus disease-2019 （COVID-19） emergency HSGs and World Health Organization （WHO） standard HSGs to uncover the core attributes of methods employed in the development of emergency HSGs. Our evaluation findings revealed that across the five assessment items of AGREE-HS， methods in the 34 emergency HSGs evaluated ranked third， trailing behind topic and recommendations. Notably， criterion 2 （the best available and most contextually relevant evidence is considered） received the highest score， whereas criterion 5 （evidence of cost and cost-effectiveness of the potential options is described） scored the lowest. Compared with the WHO standard HSGs， the COVID-19 emergency HSGs exhibited low scores in methods （P<0.05）， which was reflected in nine criteria （P<0.05）， especially in criteria 1 （systematic and transparent methods are used to identify and review the evidence） and 9 （systematic and transparent methods are used to agree upon the final recommendations）. Among the COVID-19 emergency HSGs， that developed by the WHO achieved higher scores in eight out of all nine criteria， excluding criterion 8 （P<0.05）. The clinically relevant emergency HSGs had higher scores in the criteria 3 （the evidence base is current） and 8 （the rationale behind the recommendations is clear） than other types of emergency HSGs. Collectively， the methodology for developing emergency HSGs， represented by the COVID-19 emergency HSG， underscores evidence orientation and integrates expert consensus. It is characterized by adaptable evidence synthesis strategies， streamlined evidence review protocols， and contextual relevance， all of which are influenced by external， internal， and implementation-specific factors.

The study focused on individuals with influenza-like symptoms (fever, cough, sore throat, runny nose, and other respiratory symptoms) in three kindergartens in Tongzhou District, Beijing City, in April 2023. Nasopharyngeal swab specimens were collected, and real-time fluorescent quantitative PCR was used to detect common respiratory pathogens in the collected specimens. Positive specimens were subjected to sequencing analysis of the highly variable region of human respiratory syncytial virus (HRSV) G protein, homology analysis and phylogenetic tree analysis. A total of 25 fever cases were collected from 3 kindergartens, aged 3-8 years old, with an age M ( Q1, Q3) of 4 (3.5, 5) years old. Ten confirmed cases of HRSV positive were screened and detected using the fluorescent quantitative PCR method, with a total detection rate of 40% (10/25). Typing identification and sequencing analysis confirmed that the main epidemic type was HRSV subtype B, which was highly homologous and closely related to previous epidemic strains in the region. Through pathogen investigation and analysis, it was preliminarily determined that this epidemic was dominated by HRSV subtype B.

Objective:To investigate the pathogen spectrum and the epidemiological characteristics of hospitalized severe acute respiratory tract infection (SARI) cases in a sentinel hospital in Tongzhou District of Beijing from 2019 to 2022, and provide reference for scientific prevention and control of SARI.Methods:This study enrolled SARI patients in the Beijing Luhe Hospital from January 2019 to December 2022. Nasopharyngeal swabs or respiratory secretions of the patients were collected and analyzed by quantitative real-time PCR to detect the pathogens and their types. The epidemiological and clinical characteristics of the cases were analyzed.Results:In this study, 1 124 SARI cases were enrolled, of which 379 were positive for respiratory pathogens with a detection rate of 33.72%. Most of the SARI cases were positive for bacteria pathogens, and the detection rates of Mycoplasma pneumoniae, Streptococcus pneumoniae, and Stenotrophomonas maltophilia were high. Influenza A virus, parainfluenza virus, and respiratory syncytial virus were the main viral pathogens detected in the cases. There were significant differences in the number of cases and the detection rate of respiratory pathogens among different age groups (χ 2=555, P=0.000 1). The predominant pathogens in different years were different. Mycoplasma pneumoniae [27.27% (51/187)] and influenza A virus [17.65% (33/187), ] were the predominant pathogens in 2019; parainfluenza virus [16.67% (10/60)], Mycoplasma pneumoniae [11.67% (7/60)], and Haemophilus influenzae [11.67% (7/60)] were the predominant pathogens in 2020; Stenotrophomonas maltophilia [24.39% (20/82)] and respiratory syncytial virus [19.51% (16/82)] were the predominant pathogens in 2021; Stenotrophomonas maltophilia [20% (10/50)] and parainfluenza virus [12% (6/50)] were the predominant pathogens in 2022. Conclusions:Most of the SARI cases in Tongzhou district of Beijing from 2019 to 2022 are caused by bacteria. More attention should be paid to the prevalence of Stenotrophomonas maltophilia and Mycoplasma pneumoniae, as well as the prevalence of respiratory syncytial virus, parainfluenza virus, and influenza A virus. The predominant pathogens change every year from 2019 to 2022. Therefore, the prevention and control strategies should be made accordingly. This study provides basis data for the national respiratory multipathogen surveillance program.

The study focused on individuals with influenza-like symptoms (fever, cough, sore throat, runny nose, and other respiratory symptoms) in three kindergartens in Tongzhou District, Beijing City, in April 2023. Nasopharyngeal swab specimens were collected, and real-time fluorescent quantitative PCR was used to detect common respiratory pathogens in the collected specimens. Positive specimens were subjected to sequencing analysis of the highly variable region of human respiratory syncytial virus (HRSV) G protein, homology analysis and phylogenetic tree analysis. A total of 25 fever cases were collected from 3 kindergartens, aged 3-8 years old, with an age M ( Q1, Q3) of 4 (3.5, 5) years old. Ten confirmed cases of HRSV positive were screened and detected using the fluorescent quantitative PCR method, with a total detection rate of 40% (10/25). Typing identification and sequencing analysis confirmed that the main epidemic type was HRSV subtype B, which was highly homologous and closely related to previous epidemic strains in the region. Through pathogen investigation and analysis, it was preliminarily determined that this epidemic was dominated by HRSV subtype B.

Objective:To establish a mesenchymal stem cell(MSC)-based in vitro cell model for the evaluation of mouse bone marrow acute graft-versus-host disease(aGVHD).Methods:Female C57BL/6N mice aged 6-8 weeks were used as bone marrow and lymphocyte donors,and female BALB/c mice aged 6-8 weeks were used as aGVHD recipients.The recipient mouse received a lethal dose(8.0 Gy,72.76 cGy/min)of total body γ irradiation,and injected with donor mouse derived bone marrow cells(1× 107/mouse)in 6-8 hours post irradiation to establish a bone marrow transplantation(BMT)mouse model(n=20).In addition,the recipient mice received a lethal dose(8.0 Gy,72.76 cGy/min)of total body γ irradiation,and injected with donor mouse derived bone marrow cells(1 × 107/mouse)and spleen lymphocytes(2 × 106/mouse)in 6-8 hours post irradiation to establish a mouse aGVHD model(n=20).On the day 7 after modeling,the recipient mice were anesthetized and the blood was harvested post eyeball enucleation.The serum was collected by centrifugation.Mouse MSCs were isolated and cultured with the addition of 2％,5％,and 10％recipient serum from BMT group or aGVHD group respectively.The colony-forming unit-fibroblast(CFU-F)experiment was performed to evaluate the potential effects of serums on the self-renewal ability of MSC.The expression of CD29 and CD105 of MSC was evaluated by immunofluorescence staining.In addition,the expression of self-renewal-related genes including Oct-4,Sox-2,and Nanog in MSC was detected by real-time fluorescence quantitative PCR(RT-qPCR).Results:We successfully established an in vitro cell model that could mimic the bone marrow microenvironment damage of the mouse with aGVHD.CFU-F assay showed that,on day 7 after the culture,compared with the BMT group,MSC colony formation ability of aGVHD serum concentrations groups of 2％and 5％was significantly reduced(P＜0.05);after the culture,at day 14,compared with the BMT group,MSC colony formation ability in different aGVHD serum concentration was significantly reduced(P＜0.05).The immunofluorescence staining showed that,compared with the BMT group,the proportion of MSC surface molecules CD29+and CD 105+cells was significantly dereased in the aGVHD serum concentration group(P＜0.05),the most significant difference was at a serum concentration of 10％(P＜0.001,P＜0.01).The results of RT-qPCR detection showed that the expression of the MSC self-renewal-related genes Oct-4,Sox-2,and Nanog was decreased,the most significant difference was observed at an aGVHD serum concentration of 10％(P＜0.01,P＜0.001,P＜0.001).Conclusion:By co-culturing different concentrations of mouse aGVHD serum and mouse MSC,we found that the addition of mouse aGVHD serum at different concentrations impaired the MSC self-renewal ability,which providing a new tool for the field of aGVHD bone marrow microenvironment damage.

This paper aimed to investigate the role and potential mechanism of p53 on primordial follicle activation. Firstly, the p53 mRNA expression in the ovary of neonatal mice at 3, 5, 7 and 9 days post-partum (dpp) and the subcellular localization of p53 were detected to confirm the expression pattern of p53. Secondly, 2 dpp and 3 dpp ovaries were cultured with p53 inhibitor Pifithrin-μ (PFT-μ, 5 μmol/L) or equal volume of dimethyl sulfoxide for 3 days. The function of p53 in primordial follicle activation was determined by hematoxylin staining and whole ovary follicle counting. The proliferation of cell was detected by immunohistochemistry. The relative mRNA levels and protein levels of the key molecules involved in the classical pathways associated with the growing follicles were examined by immunofluorescence staining, Western blot and real-time PCR, respectively. Finally, rapamycin (RAP) was used to intervene the mTOR signaling pathway, and ovaries were divided into four groups: Control, RAP (1 μmol/L), PFT-μ (5 μmol/L), PFT-μ (5 μmol/L) + RAP (1 μmol/L) groups. The number of follicles in each group was determined by hematoxylin staining and whole ovary follicle counting. The results showed that the expression of p53 mRNA was decreased with the activation of primordial follicles in physiological condition. p53 was expressed in granulosa cells and oocyte cytoplasm of the primordial follicles and growing follicles, and the expression of p53 in the primordial follicles was higher than that in the growing follicles. Inhibition of p53 promoted follicle activation and reduced the primordial follicle reserve. Inhibition of p53 promoted the proliferation of the granulosa cells and oocytes. The mRNA and protein expression levels of key molecules in the PI3K/AKT signaling pathway including AKT, PTEN, and FOXO3a were not significantly changed after PFT-μ treatment, while the expression of RPS6/p-RPS6, the downstream effectors of the mTOR signaling pathway, was upregulated. Inhibition of both p53 and mTOR blocked p53 inhibition-induced primordial follicle activation. Collectively, these findings suggest that p53 may inhibit primordial follicle activation through the mTOR signaling pathway to maintain the primordial follicle reserve.
Female ; Animals ; Mice ; Tumor Suppressor Protein p53/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Hematoxylin ; Signal Transduction/physiology* ; TOR Serine-Threonine Kinases ; Sirolimus ; RNA, Messenger