Background/Purpose

Type I interferon(IFN) is a critical pathogenic factor in Systemic Lupus Erythematosus(SLE) and its associated nephritis, as elevated IFN inducible genes have been found in the kidney tissues and deficiency of IFN receptor protects lupus mouse model from developing nephritis. Reduced miR-146a is in part the reason for uncontrolled IFN response in peripheral blood cells of SLE. However, we are not clear if there are abnormally expressed kidney miRNAs that are responsible for the overactivated IFN response in the renal tissue of SLE. Our previous miRNA profiling data showed that miR-127-3p was one of the most reduced miRNAs in renal biopsies of lupus nephritis patients, raising the question whether miR-127-3p plays a role in IFN signaling. In this study, we explored the regulatory function of miR-127-3p in IFN signaling and its therapeutic effects on SLE.

Methods

miR-127-3p was quantified by RT-qPCR. Interferon-stimulated response element(ISRE)-luciferase reporter assay and western blotting were used to investigate the function of miR-127-3p. Genes affected by miR-127-3p were identified by microarray. Antagomir(chemical modified miRNA inhibitors) was used to inhibit the function of miR-127-3p to validate its function. We administrated agomir(chemical modified miRNA mimics) into pristane induced lupus mouse model to investigate the in vivo function of miR-127-3p.

Results

To test its function in IFN signaling, we transfected miR-127-3p together with ISRE-luciferase reporter plasmids into Hela cells and then stimulated the cells with IFN. We found that miR-127-3p inhibited IFN mediated expression of the reporter gene. Consistently, miR-127-3p inhibited IFN induced phosphorylation of STAT1 and STAT2, which are two major upstream molecules that activate ISRE mediated gene expression. We further revealed that most of the IFN inducible genes were inhibited by miR-127-3p in Hela cells. In addition, in human primary renal mesangial cells, loss of function of miR-127-3p augmented IFN signaling including enhanced ISRE mediated reporter gene expression, stronger phosphorylation of STAT2 and elevated expression of IFN inducible genes. By Ribonucleoprotein ImmunoPrecipitation assay, we identified JAK1, the upstream tyrosine kinase of STAT1 and STAT2, as the target of miR-127-3p. To elucidate the mechanism of reduced miR-127-3p, we screened several inflammatory factors and found that IFN inhibited miR-127-3p in renal cells. What’s more, we injected IFN into the mice and found that IFN inhibited the expression of miR-127-3p in their kidneys. To test its therapeutic effects, we examined a short-term phenomenon, pulmonary hemorrhage(PH), in pristane induced lupus mouse model and found that administrating miR-127-3p alleviated PH and inhibited IFN inducible gene Mx1 in peripheral blood cells.

Conclusion

Our study shows renal miR-127-3p can inhibit IFN signaling, indicating a new mechanism of overactivated IFN response in the kidney of SLE. Preliminary in vivo data suggest miR-127-3p has therapeutic potential in SLE. Ongoing mouse model studies about the effects of miR-127-3p on lupus nephritis will give us more insights into its therapeutic value.

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« Back to 2014 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/mir-127-3p-as-a-novel-regulator-of-type-i-interferon-signaling-pathway-in-sle/