Differential regulation of different human papilloma virus variants by the POU family transcription factor Brn-3a.

The Brn-3a POU family transcription factor is overexpressed in human cervical carcinoma biopsies and is able to activate expression of the human papilloma virus type 16 (HPV-16) upstream regulatory region (URR), which drives the expression of the E6 and E7 oncoproteins. Inhibition of Brn-3a expression in human cervical cancer cells inhibits HPV gene expression and reduces cellular growth and anchorage independence in vitro as well as the ability to form tumours in vivo. Here, we show that Brn-3a differentially regulates different HPV-16 variants that have previously been shown to be associated with different risks of progression to cervical carcinoma. In human cervical material, Brn-3a levels correlate directly with HPV E6 levels in individuals infected with a high risk variant of HPV-16, whereas this is not the case for a low-risk variant. Moreover, the URRs of high- and intermediate-risk variants are activated by Brn-3a in transfection assays, whereas the URR of a low-risk variant is not. The change of one or two bases in a low-risk variant URR to their equivalent in a higher-risk URR can render the URR responsive to Brn-3a and vice versa. These results help explain why the specific interplay between viral and cellular factors necessary for the progression to cervical carcinoma only occurs in a minority of those infected with HPV-16.

Raised levels of interleukin 6 in systemic lupus erythematosus correlate with anaemia.

OBJECTIVES: Raised levels of the cytokines interleukin (IL) 6 and IL10 have been reported in patients with systemic lupus erythematosus (SLE). OBJECTIVE: To determine if levels of IL6 and IL10 correlate with organ/system-specific disease activity in SLE, using the British Isles Lupus Assessment Group (BILAG) Disease Activity Index. METHODS: Levels of IL6 and IL10 in serum samples from 171 patients with SLE and 50 normal controls were determined by enzyme linked immunosorbent assay (ELISA). Levels of cytokines in individual patients with SLE were compared with the presence or absence of active disease in eight organ/systems using the BILAG index. RESULTS: Levels of IL6 were significantly higher (p = 0.005) in patients with active compared with inactive haematological disease, as scored by the BILAG index. Further analysis showed that this association was dependent on an inverse correlation (p = 0.002, r = -0.26) between IL6 levels and haemoglobin levels in patients with SLE. In contrast, IL10 levels did not correlate with individual organ/system disease activity. CONCLUSIONS: Raised levels of IL6 in SLE may influence the development of anaemia in this disease. These findings are in agreement with an increasing number of studies, which support physiological links between IL6 and anaemia. Importantly, with the exception of the haematological system, our studies do not provide evidence of any individual organ/system which would respond to therapeutic manipulation of either IL6 or IL10 levels.

Elevated expression of the Brn-3a and Brn-3b transcription factors in systemic lupus erythematosus correlates with antibodies to Brn-3 and overexpression of Hsp90.

OBJECTIVE: Important developmental and antiapoptotic roles have been described for the Brn-3 family of transcription factors in mammalian cells. Following a report of pathogenic autoantibody-inducing T cell reactivity to the Brn-3 transcription factors in murine lupus, we undertook this study to investigate serum levels of antibodies to Brn-3 and levels of expression of Brn-3 in peripheral blood mononuclear cells (PBMCs) of patients with systemic lupus erythematosus (SLE). METHODS: Serum and PBMC samples were obtained from 87 SLE patients and 30 normal control subjects. Serum antibodies to the Brn-3a and Brn-3b transcription factors were measured by enzyme-linked immunosorbent assay. Levels of Brn-3a and Brn-3b messenger RNA (mRNA) in PBMCs were measured by reverse transcription and real-time quantitative polymerase chain reaction. RESULTS: Elevated serum levels of antibodies to Brn-3a and Brn-3b were found in 43% and 32%, respectively, of SLE patients. This elevation paralleled enhanced expression of Brn-3a and Brn-3b in PBMCs of 44% and 31%, respectively, of SLE patients. Furthermore, we observed a significant correlation (P = 0.002) between elevated levels of anti-Brn-3b antibodies and elevated levels of Brn-3b mRNA in individual patients. A preliminary analysis of possible target genes for Brn-3a and Brn-3b revealed a significant correlation (P = 0.01) between the level of Brn-3a mRNA and the level of Hsp90 protein (90-kd heat-shock protein, which is overexpressed in SLE) in PBMCs of SLE patients. In addition, we observed that overexpression of Brn-3a and Brn-3b in cultured cells enhanced expression of Hsp90 protein and transcription of Hsp90 promoter-reporter constructs. Finally, we observed an association between elevated levels of Brn-3a mRNA and active SLE (P = 0.002). CONCLUSION: Expression of both Brn-3a and Brn-3b was found to be enhanced in SLE, and this correlated with enhanced levels of autoantibodies to these proteins and with the previously reported overexpression of Hsp90, which was shown to be a novel gene regulated by Brn-3a and Brn-3b. The overexpression of Brn-3a correlated with active disease, suggesting that it may play a role in the disease process via its targeting by the immune system and its ability to induce the expression of specific genes.

Elevated levels of the 90 kDa heat shock protein (hsp90) in SLE correlate with levels of IL-6 and autoantibodies to hsp90.

Levels of the 90 kDa heat shock protein (hsp90) are elevated in a subset of patients with systemic lupus erythematosus (SLE) due to enhanced transcription of the hsp90beta gene. In cultured cells, transcription of the hsp90beta gene is induced following exposure to IL-6 or IL-10 which are known to be elevated in SLE patients. Here we have measured the levels of hsp90 protein and of IL-6, IL-10 in SLE patients and normal controls. We demonstrate that the levels of hsp90 protein in individual patients correlate with the IL-6 level but not with the level of IL-10. Moreover, hsp90 protein levels in patients correlate with the presence of IgG autoantibodies to hsp90. These results support a model in which elevated levels of IL-6 in SLE patients induce elevated levels of hsp90 protein which in turn results in the production of autoantibodies to this protein.

Interleukin-10 activates heat-shock protein 90beta gene expression.

Elevated levels of the cytokine interleukin-10 (IL-10) have been reported in patients with active systemic lupus erythematosus (SLE). Any role for IL-10 in the pathogenesis of SLE is likely to involve the activation of expression of specific genes within its target cells. We have previously reported elevated levels of the 90 000 MW heat-shock protein (hsp 90) and autoantibodies to hsp 90 in patients with SLE. Recent studies have shown that the cytokine IL-6 activates hsp 90 gene expression via specific transcription factors that include STAT-3 (signal transducer and activator of transcription 3). In view of the known role of STAT proteins in IL-10 signalling pathways, we have investigated the effect of IL-10 on hsp 90 gene expression. Here we report that IL-10 enhances the expression of hsp 90 in both a human hepatoma cell line (HepG2) stably expressing the human IL-10 receptor and peripheral blood mononuclear cells (PBMC). In reporter gene assays IL-10 is able to activate both the hsp 90alpha and hsp 90beta promoters directly. Furthermore, a short region of the hsp 90beta promoter which is activated in response to IL-10, contains a STAT-3 binding site. This element but not a mutant derivative unable to bind STAT-3, is able to confer a response to IL-10 on a heterologous promoter. These results may be understood in terms of the shared signalling mechanisms of IL-10 and IL-6 and provide evidence of a role for IL-10 in the overexpression of hsp 90 in SLE, with possible pathological consequences.