Objective To generate minichromosome maintenance protein 2(MCM2)gene knockout cervi-cal cancer HeLa cell lines using inducible CRISPR/Cas9 technology,and to explore the effect of MCM2 on DNA replication and replication stress.Methods The inducible CRISPR/Cas9 system,TLCV2,was used to construct MCM2 knockout HeLa cell lines.And the cell lines were divided into control group(Control),knockout group 1(KO1),and knockout group 2(KO2).Western blot,Edu incorporation experiment,real-time quantitative PCR(qPCR),immunofluorescence and MTT assay were used to analyze the effects of MCM2 knockout on DNA replica-tion and replication stress induced by hydroxyurea.Results The CRISPR/Cas9 system successfully knocked out the MCM2 gene after induction,and MCM2 knockout affected the stability of MCM2-7 complex.Compared with the control cells,MCM2 knockout cells had a dramatic decrease in the capacity of DNA replication,and the mRNA levels of Cyclin A1,Cyclin E1 and CDK4.Under DNA replication stress,MCM2 knockout cells decreased cell viability,DNA damage repair capacity,and increased genomic instability compared with control cells.Conclusion Knockout of MCM2 gene reduces the DNA replication capacity of HeLa cells under normal conditions and cell viability under replication stress.This study successfully generates MCM2 gene inducible knockout HeLa cell lines,laying the foundation for further research on the role and biological function of MCM2 gene in the occurrence and progression of cervical cancer.

Objective To investigate the association of triglyceride-glucose index(TyG)with non-alcoholic fatty liver disease(NAFLD)and its diagnostic value for NAFLD in non-obese individuals.Methods We retrospectively collected the data of non-obese individuals(BMI<25 kg/m2)undergoing routine health examination at Second Affiliated Hospital of Xi'an Jiaotong University between May,2020 and December,2023,who all received abdominal ultrasound examination for NAFLD screening.The nonlinear relationship between TyG and non-obese NAFLD was explored using restricted cubic splines(RCS),and LASSO regression was used for variable screening;the correlation between TyG and NAFLD risk was analyzed using multivariate logistic regression.The diagnostic value of TyG for non-obese NAFLD was assessed using receiver-operating characteristic(ROC)curves and sensitivity analysis.Results A total of 3723 non-obese subjects were enrolled in this study,including 432(11.6%)patients with NAFLD.Compared with the healthy individuals,the patients with NAFLD had significant elevations of systolic and diastolic blood pressures,total cholesterol,triglycerides,LDL-C,blood uric acid,fasting blood glucose,and TyG index and a decreased HDL-C level(P<0.05).Multivariate logistic regression revealed that for each one-unit increase of TyG,the risk of non-obese NAFLD increased by 2.2 folds(OR=3.22,95%CI:2.53-4.12,P<0.001).Compared with a TyG index in the lowest quartile Q1,a TyG index in the Q2,Q3 and Q4 quartiles was associated with an increased risk of NAFLD by 1.52 folds(OR=2.52,95%CI:1.20-5.95),3.56 folds(OR=4.56,95%CI:2.28-10.46),and 8.66-folds(OR=9.66,95%CI:4.83-22.18),respectively.The RCS curve demonstrated a significant linear correlation between TyG index and non-obese NALFD risk(P for nonlinear=0.019).For diagnosing non-obese NALFD,TyG index had an area under ROC curve of 0.819 with a sensitivity of 78.0%and a specificity of 71.2%.Conclusion An increase of TyG index is correlated with increased risks of NAFLD in non-obese individuals and can serve as an indicator for screening early NAFLD in healthy individuals.

Objective To explore the association between visceral adiposity index(VAI)and nonalcoholic fatty liver disease(NAFLD)in lean population and the predictive value of VAI.Methods A total of 2 576 healthy subjects,body mass index(BMI)＜24 kg/m2,from The Second Affiliated Hospital of Xi'an Jiaotong University from June 2020 to May 2021 were randomly included and divided into lean NAFLD(n=213)and healthy control group(n=2 363).According to the VAI quartiles,they were divided into Q1-Q4 groups from low to high.The differences in biochemical parameters and the prevalence of NAFLD were compared among groups.The correlation between VAI and lean NAFLD was analyzed with restricted cubic spline(RCS),and the predictive value of VAI was explored by Logistic regression and receiver operating characteristic(ROC)curve.Results A total of 2 576 participants were included,and the prevalence of lean NAFLD was 8.3％(213 cases).The mean age,male ratio,BMI and waist circumference(WC)from group Q1 to group Q4 were significantly increased in a dose-response relationship(all P＜0.001).Compared with those in group Q1,systolic blood pressure,diastolic blood pressure,white blood cell count,hemoglobin concentration,alanine aminotransferase,aspartate aminotransferase,γ-glutamyl transpeptidase,alkaline phosphatase,total cholesterol,triglyceride,low-density lipoprotein cholesterol,blood uric acid,and fasting blood glucose levels in groups Q2 to Q4 were significantly increased,while direct bilirubin and high-density lipoprotein cholesterol levels were gradually decreased(both P＜0.001).The prevalence rate of NAFLD in groups Q1-Q4 was 0.6％,3.3％,7.0％and 22.2％,respectively(P＜0.001).RCS showed that the risk of NAFLD in lean population rose significantly with the increase of VAI(P＜0.001),and there was a nonlinear relationship between them(P for nonlinear＜0.001).Logistic regression showed that after adjusting other confounding factors,the risk of lean NAFLD in groups Q2,Q3 and Q4 was still 2.926 times(95％CI:0.971-8.811),3.435 times(95％CI:1.154-10.230),and 5.920 times(95％CI:1.873-18.719)that Q1 group.ROC curve showed that VAI had a good predictive value for lean NAFLD,with area under the curve of 0.815,critical value of 1.532,diagnostic sensitivity of 77.9％and specificity of 72.8％,which were better than BMI and WC.Conclusion VAI is significantly associated with the risk of NAFLD in lean population,and thus has a good predictive value.It can be used for early screening and diagnosis of lean NAFLD.

Objective To investigate the association of triglyceride-glucose index(TyG)with non-alcoholic fatty liver disease(NAFLD)and its diagnostic value for NAFLD in non-obese individuals.Methods We retrospectively collected the data of non-obese individuals(BMI<25 kg/m2)undergoing routine health examination at Second Affiliated Hospital of Xi'an Jiaotong University between May,2020 and December,2023,who all received abdominal ultrasound examination for NAFLD screening.The nonlinear relationship between TyG and non-obese NAFLD was explored using restricted cubic splines(RCS),and LASSO regression was used for variable screening;the correlation between TyG and NAFLD risk was analyzed using multivariate logistic regression.The diagnostic value of TyG for non-obese NAFLD was assessed using receiver-operating characteristic(ROC)curves and sensitivity analysis.Results A total of 3723 non-obese subjects were enrolled in this study,including 432(11.6%)patients with NAFLD.Compared with the healthy individuals,the patients with NAFLD had significant elevations of systolic and diastolic blood pressures,total cholesterol,triglycerides,LDL-C,blood uric acid,fasting blood glucose,and TyG index and a decreased HDL-C level(P<0.05).Multivariate logistic regression revealed that for each one-unit increase of TyG,the risk of non-obese NAFLD increased by 2.2 folds(OR=3.22,95%CI:2.53-4.12,P<0.001).Compared with a TyG index in the lowest quartile Q1,a TyG index in the Q2,Q3 and Q4 quartiles was associated with an increased risk of NAFLD by 1.52 folds(OR=2.52,95%CI:1.20-5.95),3.56 folds(OR=4.56,95%CI:2.28-10.46),and 8.66-folds(OR=9.66,95%CI:4.83-22.18),respectively.The RCS curve demonstrated a significant linear correlation between TyG index and non-obese NALFD risk(P for nonlinear=0.019).For diagnosing non-obese NALFD,TyG index had an area under ROC curve of 0.819 with a sensitivity of 78.0%and a specificity of 71.2%.Conclusion An increase of TyG index is correlated with increased risks of NAFLD in non-obese individuals and can serve as an indicator for screening early NAFLD in healthy individuals.

Objective    To analyze the influencing factors for re-positive nucleic acid test in discharged corona-virus disease 2019 (COVID-19) patients in Chengdu, Sichuan Province, and to provide data support for the epidemics prevention and control. Methods    The clinical data of 660 discharged COVID-19 patients from January 23, 2020 to February 28, 2021 in our center were retrospectively analyzed. The patients were divided into two groups according to the reexamination of virus nucleic acid, including a negative group [549 patients, including 428 males and 121 females with a median age of 33.0 (28.0, 48.0) years] and a positive group [111 patients, including 76 males and 35 females with a median age of 39.0 (28.0, 51.0) years]. The clinical data of the two groups were compared. Results     The re-positive rate of the discharged patients was 16.82%. Univariate analysis showed that the re-positive rate of females was higher than that of males (χ2=4.608, P=0.032). The re-positive rate of confirmed patients was higher than that of asymptomatic infected patients (χ2=8.140, P=0.004). The re-positive rate of domestic patients was higher than that of imported patients (χ2=9.178, P=0.002). The counts of CD3+ (P=0.038), CD4+ (P=0.048) and CD8+ (P=0.040) T lymphocytes in the negative group were higher than those in the positive group. The binary logistic regression analysis showed that the clinical classification and CD8+ T lymphocyte count were independent risk factors affecting the recurrence of virility. Conclusion    The gender, origin, T lymphocyte subsets count and clinical type are the influencing factors for re-positive result, and clinical type and CD8+ T lymphocyte count are the independent influencing factors for re-positive result. Therefore, improving the immunity of infected patients, as well as early detection and timely treatment are effective means to reduce the re-positive occurrence.

Objective:To investigate the role of dendritic cells (DC) in Chlamydia muridarum ( Cm) respiratory infection and their effect on adaptive immune response. Methods:C57BL/6 mice were exposed to 1×10 3 inclusion-forming units (IFU) of Cm through inhalation to establish the mouse model of Cm respiratory infection. The proportion of CD11c + MHCⅡ + DC and the expression of costimulatory molecules (CD40, CD80 and CD86) in spleen tissues were detected by flow cytometry on 0, 3 and 7 d after infection. The expression of IL-12p40, IL-10 and IL-6 at mRNA level in spleen tissues was detected by qPCR. Mouse splenic DC isolated on 7 d after Cm infection were sorted by magnetic beads and then transferred to recipient mice. Th1 response in the recipient mice was measured using intracellular cytokine staining 14 d after infection. Results:Cm respiratory infection induced massive infiltration of DC and promoted the expression of costimulatory molecules on splenic DC. The expression of IL-12 and IL-10 at mRNA level in splenic DC reached the peak on 3 d after infection. Transferring the splenic DC of Cm-infected mice into the recipient mice could alleviate the disease condition in the recipient mice after Cm infection with reduced Cm inclusion-forming units in lung tissues and significantly increased proportion of Th1 cells in lung and spleen tissues. Conclusions:Cm respiratory infection could induce the maturation and activation of DC, which promoted Th1 immune response. DC played an important role in Cm infection.

Objective:To investigate the role of IL-21/IL-21R-mediated CD4 + T cells in Chlamydia muridarum ( Cm) respiratory infection. Methods:C57BL/6 mice (WT mice) and IL-21R -/- mice were used to establish the models of Cm respiratory infection through intranasal inhalation of Cm. Flow cytometry was used to detect the proportion, number, activity and function of CD4 + T cells in lung and spleen tissues at 0, 3, 7 and 14 d after Cm respiratory tract infection. IFN-γ and IL-4 levels in spleen cell culture supernatants were detected by ELISA. Na?ve WT mice were transferred with CD4 + T cells in the spleen tissues of IL-21R -/- mice or WT mice on 7 d after infection and given Cm intranasally 2 h later. Then the mice were weighed daily and sacrificed on 14 d after infection. The bacterial load and pathological changes in lung were analyzed. Flow cytometry was performed to detect the proportions and numbers of neutrophils (CD45 + CD11b + Gr-1 high) and alveolar macrophages (CD45 + F4/80 + CD11c high)as well as the proportions of Th1 (IFN-γ + CD4 + ) and Th2 (IL-4 + CD4 + ) cells. ELISA was also performed to measure IFN-γ and IL-4 levels in spleen cell culture supernatants. Results:Compared with WT mice, IL-21R -/- mice showed elevated numbers and enhanced activation of CD4 + T cells, increased proportion of Th1 cells and decreased proportion of Th2 cells in spleen and lung tissues after Cm respiratory infection. Besides, IFN-γ levels increased, while IL-4 levels decreased in spleen cell culture supernatants of IL-21R -/- mice. After Cm infection, the na?ve WT transferred with CD4 + T cells from IL-21R -/- mice showed less body weight loss, reduced bacterial load and alleviated pathological changes in lung tissues, increased proportion of Th1 cells in lung tissue and higher IFN-γ level in spleen cell culture supernatants. Conclusions:IL-21/IL-21R-mediated CD4 + T cells could aggravate Cm respiratory infection by suppressing Th1 cell immune responses.

Objective:To investigate the effects of Chlamydia muridarum ( Cm) respiratory tract infection on the infiltration and polarization of alveolar macrophages (AMs) and pulmonary interstitial macrophages (IMs). Methods:A C57BL/6 mouse model of Cm respiratory tract infection was established through nasal inhalation. Flow cytometry was used to detect AMs (CD45 + F4/80 + CD11c + ) and IMs (CD45 + F4/80 + CD11c -) in lung tissues at 0, 3, 7 and 14 d after Cm respiratory tract infection. The proportions of M1 (CD80 + , CD86 + , MHCⅡ + , iNOS + ) and M2 (CD206 + , Arg1 + ) macrophages in AMs and IMs were also detected. Results:(1) Cm respiratory tract infection induced the infiltration of AMs and IMs. Compared with the uninfected group (0 d), the proportions and the numbers of AMs and IMs of were significantly increased 3 d after infection ( P<0.05, P<0.01). The numbers of AMs and IMs reached the peak 7 d after infection ( P<0.001). (2) Compared with the uninfected group, the proportions of CD80 + and CD86 + cells in AMs were significantly up-regulated 3 d after infection ( P<0.05, P<0.01); the proportion of MHCⅡ + cells in AMs increased after infection and reached the peak at 14 d ( P<0.05), while the proportion of CD206 + cells decreased after infection ( P<0.05). (3) Compared with the uninfected group, the proportions of CD80 + and CD86 + cells in IMs were increased 3 d after infection ( P<0.05, P<0.001) and the proportion of MHCⅡ + cells was significantly increased 14 d after infection ( P<0.01), while there was no significant change in the proportion of CD206 + cells. (4) In AMs, the proportion of iNOS + cells increased continuously after infection ( P<0.01), while the proportion of Arg1 + cells decreased continuously after infection, especially at 7 d and 14 d ( P<0.05). In IMs, the proportion of iNOS + cells reached the peak at 7 d ( P<0.001), but the proportion of Arg1 + cells showed no significant change after infection. Conclusions:Cm respiratory tract infection induced the infiltration of AMs and IMs, stimulated the polarization of AMs and IMs towards the M1 phenotype and weakened the polarization of AMs to M2 macrophages, but had no significant influence on the polarization of IMs towards the M2 phenotype.

Objective: To investigate the effects of exosomes from human adipose-derived mesenchymal stem cells (ADSCs) on inflammatory response of mouse RAW264.7 cells and wound healing of full-thickness skin defects in mice. Methods: The experimental research methods were adopted. The discarded adipose tissue was collected from 3 female patients (aged 10-25 years) who underwent abdominal surgery in the First Affiliated Hospital of Air Force Medical University. ADSCs were extracted from the adipose tissue by collagenase Ⅰ digestion and identified with flow cytometry. Exosomes were extracted from the human ADSCs by differential ultracentrifugation, the morphology of the exosomes was observed by transmission electron microscopy, the particle diameter of the exosomes was detected by nanoparticle tracking analyzer, and the protein expressions of CD9, CD63, tumor susceptibility gene 101 (TSG101), and β-actin were detected by Western blotting. The human ADSCs exosomes (ADSCs-Exos) and RAW264.7 cells were co-cultured for 12 h, and the uptake of RAW264.7 cells for human ADSCs-Exos was observed. The RAW264.7 cells were divided into phosphate buffer solution (PBS) group stimulated with PBS for suitable time, endotoxin/lipopolysaccharide (LPS) stimulation 2 h group, LPS stimulation 4 h group, LPS stimulation 6 h group, LPS stimulation 12 h group, and LPS stimulation 24 h group stimulated with LPS for corresponding time, with 3 wells in each group, and the mRNA expressions of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), IL-6, and IL-10 were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR) method. The RAW264.7 cells were divided into PBS group, LPS alone group, and LPS+ADSCs-Exos group, with 3 wells in each group, which were dealt correspondingly for the time screened out in the previous experiment, the mRNA expressions of IL-1β, TNF-α, IL-6, IL-10, trasforming growth factor β (TGF-β,) and vascular endothelial growth factor (VEGF) were detected by real time fluorescence quantitative RT-PCR method, and the protein expressions of inducible nitric oxide synthase (iNOS) and arginase 1 (Arg1) were detected by Western blotting. Twenty-four 8-week-old male BALB/c mice were divided into PBS group and ADSCs-Exos group according to the random number table, with 12 mice in each group, and a full-thickness skin defect wound with area of 1 cm×1 cm was inflicted on the back of each mouse. Immediately after injury, the wounds of mice in the two groups were dealt correspondingly. On post injury day (PID) 1, the concentration of IL-1β and TNF-α in serum were detected by enzyme-linked immunosorbent assay, and the mRNA expressions of IL-1β, TNF-α, and IL-6 were detected by real time fluorescence quantitative RT-PCR method. On PID 3, 6, 9, 12, and 15, the wound healing was observed and the wound non-healing rate was calculated. On PID 15, the defect length of skin accessory and collagen volume fraction (CVF) were detected by hematoxylin eosin staining and Masson staining, respectively, the CD31 expression and neovascularization were detected by immunohistochemistry, and the ratio of Ki67 positive cells, the ratio of iNOS and Arg1 double positive cells, and the ratio of iNOS positive cells to Arg1 positive cells and their fluorescence intensities were detected by immunofluorescence method. The number of samples in animal experiments was 6. Data were statistically analyzed with analysis of variance for repeated measurement, one-way analysis of variance, and independent sample t test. Results: At 12 h of culture, the cells exhibited a typical spindle shape, which were verified as ADSCs with flow cytometry. The exosomes with a vesicular structure and particle diameters of 29-178 nm, were positively expressed CD9, CD63, and TSG101 and negatively expressed β-actin. After 12 h of co-culture, the human ADSCs-Exos were endocytosed into the cytoplasm by RAW264.7 cells. The mRNA expressions of IL-1β, TNF-α, IL-6, and IL-10 of RAW264.7 cells in LPS stimulation 2 h group, LPS stimulation 4 h group, LPS stimulation 6 h group, LPS stimulation 12 h group, and LPS stimulation 24 h group were significantly higher than those in PBS group (with t) values of 39.10, 14.55, 28.80, 4.74, 48.80, 22.97, 13.25, 36.34, 23.12, 18.71, 29.19, 41.08, 11.68, 18.06, 8.54, 43.45, 62.31, 22.52, 21.51, and 37.13, respectively, P<0.01). The stimulation 12 h with significant expressions of all the inflammatory factors was selected as the time point in the following experiment. After stimulation of 12 h, the mRNA expressions of IL-1β, TNF-α, IL-6, and IL-10 of RAW264.7 cells in LPS alone group were significantly higher than those in PBS group (with t values of 44.20, 51.26, 14.71, and 8.54, respectively, P<0.01); the mRNA expressions of IL-1β, TNF-α, and IL-6 of RAW264.7 cells in LPS+ADSCs-Exos group were significantly lower than those in LPS alone group (with t values of 22.89, 25.51, and 8.03, respectively, P<0.01), while the mRNA expressions of IL-10, TGF-β, and VEGF were significantly higher than those in LPS alone group (with t values of 9.89, 13.12, and 7.14, respectively, P<0.01). After stimulation of 12 h, the protein expression of iNOS of RAW264.7 cells in LPS alone group was significantly higher than that in PBS group and LPS+ADSCs-Exos group, respectively (with t values of 11.20 and 5.06, respectively, P<0.05 or P<0.01), and the protein expression of Arg1 was significantly lower than that in LPS+ADSCs-Exos group (t=15.01, P<0.01). On PID 1, the serum concentrations of IL-1β and TNF-α and the mRNA expressions of IL-1β, TNF-α, and IL-6 in wound tissue of mice in ADSCs-Exos group were significantly those in lower than PBS group (with t values of 15.44, 12.24, 9.24, 7.12, and 10.62, respectively, P<0.01). On PID 3, 6, 9, 12, and 15 d, the wound non-healing rates of mice in ADSCs-Exos group were (73.2±4.1)%, (53.8±3.8)%, (42.1±5.1)%, (24.1±2.8)%, and 0, which were significantly lower than (82.5±3.8)%, (71.2±4.6)%, (52.9±4.1)%, (41.5±3.6)%, and (14.8±2.5)% in PBS group, respectively (with t values of 4.77, 8.93, 5.54, 7.63, and 7.59, respectively, P<0.01). On PID 15, the defect length of skin accessory in wounds of mice in PBS group was significantly longer than that in ADSCs-Exos group (t=9.50, P<0.01), and the CVF was significantly lower than that in ADSCs-Exos group (t=9.15, P<0.01). On PID 15, the CD31 expression and the number of new blood vessels (t=12.99, P<0.01), in wound tissue of mice in ADSCs-Exos group were significantly more than those in PBS group, and the ratio of Ki67 positive cells was significantly higher than that in PBS group (t=7.52, P<0.01). On PID 15, the ratio of iNOS and Arg1 double positive cells in wound tissue of mice in PBS group was (12.33±1.97)%, which was significantly higher than (1.78±0.29)% in ADSCs-Exos group (t=13.04, P<0.01), the ratio of iNOS positive cells and the fluorescence intensity of iNOS were obviously higher than those of ADSCs-Exos group, and the ratio of Arg1 positive cells and the fluorescence intensity of Arg1 were obviously lower than those of ADSCs-Exos group. Conclusions: The human ADSCs-Exos can alleviate inflammatory response of mouse RAW264.7 cells, decrease macrophage infiltration and secretion of the pro-inflammatory cytokines, increase the secretion of anti-inflammatory cytokines to promote neovascularization and cell proliferation in full-thickness skin defect wounds of mice, hence accelerating wound healing.
Animals ; Exosomes ; Female ; Humans ; Male ; Mesenchymal Stem Cells ; Mice ; Skin ; Vascular Endothelial Growth Factor A ; Wound Healing

【Objective】 To investigate the negative emotions among university students during home quarantine under the epidemic of coronavirus disease 2019 (COVID-19) so as to provide scientific basis for psychological counseling. 【Methods】 We conducted an online questionnaire survey to collect 405 undergraduates’ and postgraduates’ DASS-21 scale scores and responses to epidemic prevention knowledge, and analyzed the university students’ negative emotions during the epidemic and influencing factors. 【Results】 Of the 405 students surveyed, 178 individuals (44.0%) had depression, 171(42.2%) felt anxious, and 119(29.4%) felt stressed. Individuals in the DASS21+ group spent much time on entertainment on the cell phone daily than those in the DASS21- group (P<0.001), and the degree of impact by COVID-19 on daily life was significantly higher (P<0.001). Correlation analysis showed that entertainment time on the cell phone, the severity of COVID-19, and the impact of the epidemic were positively related to DASS-21 scores, with correlation coefficients of 0.231, 0.143 and 0.259, respectively (all P<0.01). Binary logistic regression analysis found that mobile entertainment time for over 5 hours per day (OR=3.370, 95% CI: 1.369-8.294, P=0.008) was a risk factor for negative emotions during quarantine at home. 【Conclusion】 During quarantine at home in the epidemic of COVID-19, nearly half of university students are prone to breed negative emotions, like depression, anxiety or stress, which may be related to long-term mobile phone entertainment.