Objective To evaluate the effect and mechanism of terminal fucosylation inhibitor 2-deoxy-D-galactose (2-D-gal) on ciclosporin (CsA)-induced renal epithelial-mesenchymal transition (EMT). Methods Fifteen male C57BL/6 mice aged 8-10 weeks were randomly and evenly divided into the control group (Ctrl group), CsA group and CsA+2-D-gal group (n=5). The expression levels of fucosyltransferase 1 (FUT1), EMT-associated proteins including E-cadherin, Vimentin, α-smooth muscle actin (α-SMA) in the kidney tissues of the Ctrl and CsA groups were detected by Western blot. The expression levels of terminal fucose in the kidney tissues of Ctrl and CsA groups were determined by immunofluorescence. The renal fibrosis of mice in each group was evaluated by Masson staining. The blood urea nitrogen and serum creatinine levels of mice in each group were detected. The in vitro EMT model of renal tubular epithelial cell HK2 was induced by CsA. HK2 cells were stimulated with 0, 2.5, 5.0 and 10.0 μmol/L CsA for 24 h, respectively. In addition, HK2 cells were divided into the Ctrl, 2-D-gal, CsA and CsA+2-D-gal groups. The morphology of HK2 cells after stimulation with different concentrations of CsA and in each group was observed. The expression levels of FUT1, E-cadherin, Vimentin and α-SMA in HK2 cells after stimulation with different concentrations of CsA and in each group were detected by Western blot. The expression level of terminal fucose in HK2 cells of the Ctrl and CsA groups was measured by immunofluorescence. Results Compared with the Ctrl group, the relative expression of E-cadherin protein was down-regulated, those of FUT1, Vimentin and α-SMA proteins were up-regulated (all P < 0.05), and that of terminal fucose in the mouse kidney tissues was up-regulated in the CsA group. Compared with the Ctrl group, the blood urea nitrogen and serum creatinine levels in the CsA and CsA+2-D-gal groups were up-regulated (all P < 0.05). Compared with the CsA group, the blood urea nitrogen and serum creatinine levels in the CsA+2-D-gal group were down-regulated (both P < 0.05). Compared with the Ctrl group, the collagen fiber deposition was increased and the relative expression of α-SMA protein was up-regulated in the mouse kidney tissues of CsA and CsA+2-D-gal groups (all P < 0.05). Compared with the CsA group, the collagen fiber deposition was decreased and the relative expression of α-SMA protein in the mouse kidney tissues was down-regulated in the CsA+2-D-gal group (both P < 0.05). With the increase of CsA concentration, the morphology of HK2 cells gradually became longer and thinner from original normal cobblestone shape, the relative expression levels of FUT1, Vimentin and α-SMA protein in HK2 cells were up-regulated, and that of E-cadherin protein was down-regulated in a concentration-dependent manner. Compared with the Ctrl group, the expression level of terminal fucose of HK2 cells was up-regulated in the CsA group. After CsA treatment combined with 2-D-gal intervention, the morphology of HK2 cells in the CsA+2-D-gal group was restored to resemble that of normal HK2 cells. Compared with the CsA group, the relative expression of E-cadherin protein in HK2 cells was up-regulated, whereas those of Vimentin and α-SMA proteins were down-regulated in the CsA+2-D-gal group (all P < 0.05). Conclusions CsA may induce EMT both in vivo and in vitro, and the terminal fucosylation is increased. 2-D-gal may inhibit CsA-induced EMT by suppressing the terminal fucosylation.

Objective:To explore the risk factors associated with the clinical progression of COVID-19 infection in kidney transplant(KT)recipients during the spread of Omicron variant and evaluate the effectiveness of anti-RNA virus agents in blocking the clinical progression of COVID-19 in these recipients.Methods:Retrospective analysis was conducted for the clinical data on COVID-19 infection in 232 KT recipients followed up from December 4, 2022 to January 31, 2023 at Department of Renal Transplantation, Organ Transplantation Center, Beijing Tsinghua Changgung Hospital.Inclusion criteria were age ≥18 years and stable kidney function without renal replacement therapy.The follow-up time was 30 days after COVID-19 infection.Based upon whether or not there was an infection of COVID-19, KT recipients were divided into two groups of infection(181 cases)and non-infection(51 cases). In infection group, recipients were further assigned into two sub-groups of disease progression(n=23)and stable(158 cases)according to whether or not there was a progression to severe disease.Various factors such as gender, age, body mass index(BMI), time after transplantation, underlying diseases(history of hypertension, diabetes mellitus, coronary heart disease & chronic lung disease), smoking history and dosing of anti-RNA virus agents were collected.Pearson χ2 test or Fisher's exact probability method was utilized for examining enumeration data while Mann-Whitney U test for measurement data.Univariate Logistic regression analysis was conducted and variables with P<0.05 were included into multifactorial Logistic regression analysis to identify independent risk factors for clinical progression of COVID-19 infection in KT recipients. Results:Among 232 KT recipients, infection rate of COVID-19 was 78.0%(181/232). The clinical classification was mild(112 cases), moderate(46 cases), severe(21 cases)and critical(n=2 cases). The severe rate was 12.7%(23/181). After infection with COVID-19, the proportion of KT recipients aged ≥65 years progressing from mild/moderate to severe was higher than those aged<65 years[38.5%(5/13)vs 10.7%(18/168)]. The difference was statistically significant( P=0.014); The proportion of diabetic KT recipients progressing from mild/moderate to severe was higher than those without diabetes[19.1%(13/68)vs 8.8%(10/113)]. The difference was statistically significant( P=0.045). Univariate Logistic analysis showed similar results.Age≥65 years( OR=5.21, 95% CI: 1.54-17.64, P=0.008)or diabetes mellitus( OR=2.44, 95% CI: 1.003-5.911, P=0.049)were the risk factors for COVID-19 infection recipients progressing from mild/moderate to severe disease.Multivariate Logistic analysis revealed that age ≥65 years( OR=4.03, 95% CI: 1.14-14.34, P=0.031)was an independent risk factor for COVID-19 infection recipients progressing from mild/moderate to severe.Among 181 cases of COVID-19 mild/medium infected patients, 18 cases received nimativir/ritonavir and 10 cases had azvudine for anti-RNA virus treatment.However, none of them progressed to severe; 153 cases did not use anti-RNA virus drugs and 23 cases(15.0%)progressed to severe disease and the difference was statistically significant( P=0.028). Among 23 severe cases, 14 cases received nirmatrelvir/ritonavir and 2 cases had azivudine for anti-RNA virus treatment.The former did not progress to critical disease while 1 case in the latter progressed to critical illness and death; 1/7 recipients not using anti-RNA virus agents progressed to critical illness and died while another 6 cases did not progress to critical illness. Conclusions:KT recipients aged ≥65 years or diabetes mellitus have a greater risk of progression from mild/moderate to severe disease after COVID-19 infection.Among them, age ≥65 years is an independent risk factor for patients with COVID-19 infection to progress from mild/moderate to severe.Antiviral treatment with nirmatrelvir/ritonavir or azivudine in KT recipients during mild/moderate stage of COVID-19 infection can significantly reduce the rate of severe disease.Treatment with Nirmatrelvir/Ritonavir is still effective in the severe stage.