Effect of HMGB1 on the renal injare of systemic lupus erythematosus
Objective To explore the effect of high mobility group protein box 1(HMGB1)on the renal injure of systemic lupus erythematosus(SLE).Methods The level of HMGB1 in serum from 16 patients with SLE,14 patient with lupus nephritis(LN)and 12 healthy people was measured by ELISA.Human mesangial cells were inoeulated in the dose of 104/ml.After 24 h,cells were cultured with standard medium as control group or with medium supplemented with 10μg/L human recombinant protein HMGB1 as trial group in vitro.Then cells were collected in 6,12,24 h respectively,as well as normal control group cells.Immunocytochemieal staining was adopted to detect proliferating cell nuclear antigen(PCNA)expressions on mesangial cell in diferent groups.Immunocytochemical staining and FCM were performed to analysis the changes of TLR2,NF-κB p65 proteins expressions.Results ELISA results showed that the level of HMGB1 protein in serum were higher in patients with LN than those in SLE and healthy people.HMGB1 in serum was positively collated with proteinuria in LN.Immunocytochemical staining showed the number of positive expression cells of PCNA increased in time-dependent manner.Immunocytochemical staining and FCM indicated that HMGB1 could significantly up.regulate the expression of TLR2,NF-κB p65 protein.NF-κB D65 protein Was positively correlated with the expression of TLR2 and the positive ratio of PCNA.Conclusion HMGB1 is one of the important eytokine in the pathogenesis of lupus nephritise:HMGB1 could bind to cell-surface receptors-TLR2 of mesangial cell and effectively activate NF-κB.further promote cell proliferation,which may be one of the mechanisms in renal iniare in LN. 
 
Key words: 
Lupus nephritis; Hish mobility group protein box 1; Toll like receptor 2; NF-κB; Cell proliferation