Contribution and underlying mechanisms of CXCR4 overexpression in patients with systemic lupus erythematosus.

Aberrant expression of CXCR4 has been indicated to play a role in the pathogenesis of systemic lupus erythematosus (SLE), but the mechanism of CXCR4 dysregulation in SLE is unclear. This study is aimed to explore the clinical significance and possible mechanisms of abnormal CXCR4 expression on B cells from patients with untreated SLE. Expression of CXCR4 on peripheral B cells was determined by flow cytometry and western blotting. Freshly isolated B cells were cultured with exogenous interleukin 21(IL-21) in the presence or absence of CD40 ligand (CD40L) plus anti-IgM antibody (aIgM), and changes in CXCR4 expression were detected. Involvement of phosphatidylinositol 3 kinase (PI3K)/Akt and Janus kinase/Signal transducer and activator of transcription (JAK/STAT) signaling pathways was assessed by adding blocking agents Ly294002 and AG490. Since CD63 is reported to mediate endosomal recruitment of CXCR4 and BCL6 is capable of silencing CD63 gene transcription, we also measured BCL6 and CD63 gene transcription with real-time PCR. It was shown that CXCR4 expression on B cells was significantly upregulated in SLE patients, especially in those with lupus nephritis, and was positively correlated with SLE Disease Activity Index scores and negatively with the serum complement 3 levels (P<0.05). Downregulation of CXCR4 by IL-21 was intact. In contrast, a similar effect of aIgM plus CD40L in downregulating CXCR4 expression was defective in SLE patients but was restored by co-stimulation with IL-21 in vitro. Both Ly294002 and AG490 promoted downregulation of surface CXCR4 expression on B cells from SLE patients (P=0.078 and P=0.064). Furthermore, B cells from SLE patients exhibited diminished CD63 mRNA and enhanced BCL6 mRNA expression (both P<0.05). To sum up, CXCR4 was overexpressed on SLE B cells, positively correlating with disease activity and kidney involvement. Overactivation of the PI3K/Akt and JAK/STAT pathways as well as defective CD63 synthesis may contribute to CXCR4 dysregulation in SLE.

Comparison of Tripterygium wilfordii Hook F with methotrexate in the treatment of active rheumatoid arthritis (TRIFRA): a randomised, controlled clinical trial.

OBJECTIVES: To compare the efficacy and safety of Tripterygium wilfordii Hook F (TwHF) with methotrexate (MTX) in the treatment of active rheumatoid arthritis (RA). METHODS: Design: a multicentre, open-label, randomised controlled trial. All patients were assessed by trained investigators who were unaware of the therapeutic regimen. INTERVENTION: 207 patients with active RA were randomly allocated (1:1:1) to treatment with MTX 12.5 mg once a week, or TwHF 20 mg three times a day, or the two in combination. At week 12, if reduction of the 28-joint count Disease Activity Score (DAS28) was <30% in the monotherapy groups, the patient was switched to MTX+TwHF. The primary efficacy point was the proportion of patients achieving an American College of Rheumatology (ACR) 50 response at week 24. RESULTS: 174/207 (84.1%) patients completed 24 weeks of the trial. In an intention-to-treat analysis, the proportion of patients reaching the ACR50 response criteria was 46.4% (32/69), 55.1% (38/69) and 76.8% (53/69), respectively, in the MTX, TwHF and MTX+TwHF groups (TwHF vs MTX monotherapy, p=0.014; MTX+TwHF vs MTX monotherapy, p<0.001). Similar statistically significant patterns at week 24 were found for ACR20, ACR70, clinical Disease Activity Index good responses, EULAR good response, remission rate and low disease activity rate. Significant improvement in the Health Assessment Questionnaire and 36-item Short-Form Health Survey questionnaire scores from baseline to week 24 was seen in each treatment arm (p<0.05), though no significant difference was found among the treatment arms (p>0.05). The result of per-protocol analysis agreed with that seen in the intention-to-treat analysis. Seven, three and five women in the TwHF, MTX and combination groups, respectively, developed irregular menstruation (TwHF vs MTX monotherapy, p=0.216). CONCLUSIONS: TwHF monotherapy was not inferior to, and MTX+TwHF was better than, MTX monotherapy in controlling disease activity in patients with active RA. TRIAL REGISTRATION NUMBER: NCT01613079.

Defective PTEN regulation contributes to B cell hyperresponsiveness in systemic lupus erythematosus.

PTEN regulates normal signaling through the B cell receptor (BCR). In systemic lupus erythematosus (SLE), enhanced BCR signaling contributes to increased B cell activity, but the role of PTEN in human SLE has remained unclear. We performed fluorescence-activated cell sorting analysis in B cells from SLE patients and found that all SLE B cell subsets, except for memory B cells, showed decreased expression of PTEN compared with B cells from healthy controls. Moreover, the level of PTEN expression was inversely correlated with disease activity. We then explored the mechanisms governing PTEN regulation in SLE B cells. Notably, in normal but not SLE B cells, interleukin-21 (IL-21) induced PTEN expression and suppressed Akt phosphorylation induced by anti-immunoglobulin M and CD40L stimulation. However, this deficit was not primarily at the signaling or the transcriptional level, because IL-21-induced STAT3 (signal transducer and activator of transcription 3) phosphorylation was intact and IL-21 up-regulated PTEN mRNA in SLE B cells. Therefore, we examined the expression of candidate microRNAs (miRs) that could regulate PTEN: SLE B cells were found to express increased levels of miR-7, miR-21, and miR-22. These miRs down-regulated the expression of PTEN, and IL-21 stimulation increased the expression of miR-7 and miR-22 in both normal and SLE B cells. Indeed, a miR-7 antagomir corrected PTEN-related abnormalities in SLE B cells in a manner dependent on PTEN. Therefore, defective miR-7 regulation of PTEN contributes to B cell hyperresponsiveness in SLE and could be a new target of therapeutic intervention.