[Role of anti c-mpl antibody in systemic lupus erythematosus with thrombocytopenia].

OBJECTIVE: To determine whether anti-thrompoietin receptor (TPO-R, c-mpl) antibody contributes to thrombocytopenia in systemic lupus erytematosus (SLE) and explore the pathogenic role of this antibody. METHODS: Sera from 24 SLE patients with thrombocytopenia, 27 SLE patients having normal platelet counts with a history of thrombocytopenia, 18 SLE patients with neither thrombocytopenia nor post thrombocytopenia and 18 healthy controls were collected. Anti c-mpl antibodies were detected by an indirected ELISA assay. The serum TPO levels were measured by an ELISA assay. Clinical findings, autoantibody profiles, and SLEDAI were evaluated. RESULTS: Serum anti c-mpl antibodies were detected in 18.8% of the SLE patientis. The frequency of this antibody in SLE with thrombocytopenia, SLE with a history of thrombocytopenia and SLE without thrombocytopenia were of no difference (P=0.600). In the patients with anti c-mpl antibodies, their platelet counts were decreased(P=0.025) and serum TPO levels elevated(P=0.038) than those in the patients without, while there were no differences between the two groups in C3, C4, ESR, CRP level, the frequency of ANA, dsDNA, ANCA and SLEDAI. CONCLUSION: Anti c-mpl antibody contributes to SLE-associated thrombocytopenia by functionally blocking an interaction between thrombopoietin and c-mpl, which might inhibit TPO-dependent megakaryocyte proliferation and differentiation.

[The role of promoter CpG islands methylation of leptin gene in osteoarthritis].

OBJECTIVE: To investigate the effects of 5-Aza-CdR (methylation transferase inhibitor)on the expression levels of leptin gene in chondrocytes and methylation states of leptin promoter region between osteoarthritis (OA) group and control. METHODS: The chondrocytes in osteoarthritis group were treated with 5-Aza-CdR with different doses and time-points, and the expression level of leptin was detected by real-time polymerase chain reaction for picking up the optimum dose and time-point. Next, the chondrocytes in 5 osteoarthritis patients and 5 control patients (amputation due to severe trauma) were treated with 5-Aza-CdR. Lastly, leptin mRNA expression levels in the four groups osteoarthritis and control chondrocytes treated with/without 5-Aza-CdR were measured by real-time PCR and the methylation state of promoter region (-280 - +79) was detected by epitope quantitative DNA methylation analysis. RESULTS: (1) After treating the chondrocytes in OA groups with 10 µmol/L 5-Aza-CdR for 72 h, the mRNA expression levels of leptin were increased significantly. (2) The mRNA expression levels of leptin were significantly different among the four groups (P < 0.05), and the chondrocytes in osteoarthritis groups treated with 5-Aza-CdR showed a marked induction of leptin mRNA expression. (3) Analysis of quantitative methylation data using an unsupervised hierarchical clustering algorithm, showed that methylation patterns of leptin promoter was different between control and osteoarthritis chondrocyte treated with/without 5-Aza-CdR. CONCLUSION: Demethylation of leptin promoter might up-regulate leptin gene expression level and it might contribute to osteoarthritis.

Screening disease-associated proteins from sera of patients with rheumatoid arthritis: a comparative proteomic study.

BACKGROUND: Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation at the synovial membrane. Although great progress has been made recently in exploring the etiology and pathogenesis of RA, its molecular pathological mechanism remains to be further defined and it is still a great challenge in determining the diagnosis and in choosing the appropriate therapy in early patients. This study was performed to screen candidate RA-associated serum proteins by comparative proteomics to provide research clues to early diagnosis and treatment of RA. METHODS: Sera isolated from 6 RA patients and 6 healthy volunteers were pooled respectively and high-abundance proteins were depleted by Plasma 7 Multiple Affinity Removal System. The protein expression profiles between the two groups were then compared by two-dimensional gel electrophoresis (2-DE) and the proteins over/under-expressed by more than 3-fold were identified by mass spectrometry analysis. To validate the differential expression levels of the identified proteins between the two groups, ELISA was performed in two of the identified proteins in individual sera from 32 RA patients and 32 volunteers. RESULTS: Eight proteins which over/under-expressed in sera of RA patients were identified. Among them, chain A of transthyretin (TTR) was under-expressed, while serum amyloid A protein, apolipoprotein A (ApoA)-IV, ApoA-IV precursor, haptoglobin 2, ceruloplasmin (Cp), immunoglobulin superfamily 22 and HT016 were over-expressed. ELISA test confirmed that Cp expressed remarkably higher while TTR obviously lower in RA group compared with volunteer group. CONCLUSION: There were 8 identified proteins differentially expressed between RA group and volunteer group, which might be candidate RA-associated proteins and might be promising diagnostic indicators or therapeutic targets for RA.