Expression And Clinical Significance Of Autophagy-related Genes In Peripheral Blood Mononuclear Cells Of Systemic Sclerosis

Objective:To investigate the clinical features,laboratory characteristics of Systemic Sclerosis(SSc),risk factors of SSc with interstitial lung disease(ILD)and risk factors of SSc with hematologic system damages,in Northeast Sichuan.To investigate the expression and clinical significance of autophagy-related genes LC3,Beclin 1,ATG3,ATG5,ATG12 and ATG16L1 in peripheral blood mononuclear cells(PBMCs)of SSc.Methods:The clinical data were collected from January 2010 to April 2020,at the Affiliated Hospital of North Sichuan Medical College.According to inclusion and exclusion criteria of ILD,they were divided into SSc-ILD group and SSc-NILD group.According to inclusion and exclusion criteria of hematologic system damages,they were divided intoSSc withhematologic system damages group and SSc without hematologic system damages group.The demographic information,clinical symptoms,imaging examinations,laboratory tests,the risk factors of SSc-ILD and the risk factors of hematologic system damages were analyzed retrospectively.2.51 cases of SSc and 60 cases of healthy control were collected from April 2018 to November 2020,in the Affiliated Hospital of North Sichuan Medical College,isolation and extraction of mononuclear cells(PBMCs),total RNA extraction,real-time quantitative PCR(RT-qPCR)detection the expression of LC3,Beclin 1,ATG5,ATG12,ATG16L1 in two groups of PBMCs.Analyzed the relationship between autophagy related genes and clinical data.3.t-test,Mann-Whitney U,Chi-square(χ2)test,Fisher’s exact test,Bivariate logistic regression and Spearman test were used for statistical analysis.P<0.05 was considered statistically significant.Results:1.General condition:There were 287 patients with systemic sclerosis,including 53 males,234 females,115 cases of diffuse cutaneous SSc(40.07%)and 172 cases of limited cutaneous SSc(59.93%).The average age is 52.21±12.44.Clinical symptoms:There were multiple systems damages in SSc,with respiratory system damages,hematological system damages and digestive system were common observed.2.Among 167 SSc patients,111(66.5%)cases were complicated with ILD.Age,age of onset,and disease course in the ILD group significantly higher than those in the NILD group(all P<0.05).Cough/coughing sputum,and polypnea were significantly more frequent in the ILD group than in the NILD group(all P<0.05),while finger tip pitting scars were more frequent in the NILD group than in the ILD group(P<0.05).Cardiac ultrasound:the incidence of left ventricular diastolic dysfunction(LVDD)was significantly higher in the ILD group than in the NILD group(P<0.05).Erythrocyte sedimentation rate(ESR)and the positive rate of anti-Scl-70 antibody was significantly higher in the ILD group,while the positive rate of anti-U1-RNP antibody was significantly lower(all P<0.05).Binary logistic regression analysis revealed that older age at onset,increased ESR,and positive anti-Scl-70 antibody may be the risk factor of ILD(OR values were 1.063,2.636 and 4.108,all P<0.05).3.Among 180 SSc patients,70(38.9%)cases were complicated with hematologic system damages.51(72.9%)cases had anemia,24 cases(34.3%)had leukopenia,24 cases(34.3%)had thrombocytopenia,and 22 cases had hematologic system damages associated with more than two cell line involvement.Arthritis was significantly higher in the hematologic system damages group(P<0.05).Laboratory tests:ESR and hsCRP were increased in the hematologic system damages group,while the albumin decreased(all P<0.05).The positive rates of anti-dsDNA antibody and anti-ribosomal P protein antibody was higher in the hematologic system damages group(all P<0.05).Logistic regression analysis showed that positive of anti-ribosomal P protein antibody miay be a risk factor for SSc complicated with hematologic system damages(OR values was 3.930,P<0.05).4.LC3,Beclin 1,and ATG3 were highly expressed in SSc compared with healthy control[LC3:0.78(0.60)×10-3 vs.0.52(0.54)×10-3;Beclin 1:6.68(3.56)×10-3 vs.5.22(3.54)×10-3;ATG3:17.58(12.33)×10-3 vs.11.00(4.56)×10-3,P<0.05],however ATG5,ATG12 and ATG16L1 of autophagy-related genes were not statistically significant[ATG5:6.67(3.58)×10-3 vs.6.67(2.64)×10-3;ATG12:8.64(5.56)×10-3 vs.8.57(4.66)×10-3:ATG16L1:2.69(2.19)×103 vs.2.52(2.26)×10-3,all P<0.05].LC3 was positively correlated with Age(r=0.662)and ESR(r=0.3 55)(all P<0.05).Conclusions:1.SSc-ILD is common,older onset age,increased ESR and positive Anti-Scl-70 antibody may be the risk factors for the occurrence of ILD in SSc.SSc patients with ILD may be more likely to develop cardiac damages.2.SSc complicated with hematologic system damages is common too,and more suffer from arthritis and increased markers of inflammation.Anti-ribosomal P protein antibody may be a risk factor of SSc with hematologic system damages.3.Autophagy-related genes(LC3,Beclin 1 and ATG3)were increased in PBMCs of SSc compared with healthy control,suggested that autophagy is the pathogenesis of systemic sclerosis.