Background/Purpose:

Type I interferon (IFN) signaling has been  a central pathogenic pathway in systemic lupus erythematosus (SLE). The application of specific inhibitors of IFN  pathway has emerged as a promising treatment for SLE and it would be interesting to pharmacologically modulate the sensitivity to IFNa receptor stimulation .In this study, we screened 463 genes to identify novel regulators  and tried to find a novel therapeutic target for the over-activated IFN signaling in SLE.

Methods:

High throughput ISRE-luciferase assay was used to screen candidate genes regulating IFN signaling pathway. Western blot was used to investigate IFN signal transduction. qRT-PCR was used to detect the expression of individual ISGs. Differential expression of CDK1 and ISGs between SLE patients and healthy controls was analyzed using data from RNA-seq and microarray experiments.

Results:

We developed a high-throughput ISRE-luciferase assay by co-transfection of ISRE-luciferase plasmids with a siRNA library of 463 genes in HELA cells. 60 genes which significantly enhanced ISRE activity (greater than 2 folds) and 14 genes which inhibited ISRE activity (approximately 50% reduction) were identified.  And then we analysed expression of candidate genes in whole blood from SLE patients and healthy donors by using microarray data. As CDK1 could effected ISRE activity obviously and had a differiential expression between SLE patients and healthy control.What’s more , CDK inhibitors also functioned in many clinnical trials for malignancy disease,we wonder whether CDK1 inhibitor could be a repositioning drug for SLE. Since we have seen that CDK1 enhanced IFN induced ISRE mediated reporter gene expression, we further tested the expression of ISGs and IFN induced phosphorylation of STAT1 could also be altered by knocking down CDK1 . After identifying the vital effect of CDK1 on IFN signaling, we wondered whether CDK1 was responsible for the amplified IFN signaling in SLE patients. We found CDK1 was over-expressed in peripheral blood mononuclear cells (PBMCs) and renal biopsies of SLE patients and was positively correlated with the “IFN scores”. Meanwhile, CDK1 expressed higher in the patients with severe disease than those with mild or moderate disease. Since we have proposed that CDK1 might be the reason for excessive IFN signaling in SLE, we further tested if CDK1 inhibitor, RO-3306, could alleviate the over-activated IFN signaling in SLE patients. PBMCs obtained from 5 SLE patients who had high IFN scores were treated with RO-3306 and the expression of ISGs were significantly reduced.Meanwhile, RO-3306 could also function in kidney cells from lupus mice expressed high level of ISGs . These indicated a potential role of RO-3306 as a candidate for modulating IFN signaling sensitivity in SLE patients.

Conclusion:

Our data suggest that CDK1 is a positive regulator of IFN signaling pathway. Over-expression of CDK1 in SLE might contribute to the abnormally amplified type I IFN signaling and inhibition of CDK1 could be used to interfere with the type I IFN signaling in SLE. Our data extend the knowledge of specific mechanism of abnormal IFN signaling pathway in SLE, and indicate a novel therapeutic target for SLE treatment.

« Back to 2015 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/identification-of-cyclin-dependent-kinase-1-as-a-novel-regulator-for-controlling-type-i-interferon-signaling-in-systemic-lupus-erythematosus/