Background/Purpose:

1) To identify and characterize miRNAs related to the pathogenesis of CVD in antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE) patients; 2) To evaluate the effect of specific autoantibodies in the regulation of miRNAs related to the pro-atherothrombotic status in both disorders.

Methods:

In silico searching allowed the identification of a number of miRNAs involved in the regulation of atherothrombosis. Six miRNAs (miR-124a, -125a, -125b, -146a, -155, and -222) were selected and quantified by RT-PCR in leukocytes from 20 APS and 43 SLE patients, and 28 healthy donors. Pro-inflammatory and prothrombotic proteins and oxidative stress markers were evaluated by flow cytometry. Proteins related to the biogenesis of miRNAs were quantified by RT-PCR and Western Blot. The clinical cardiovascular disease (CVD) profile was further recorded in APS and SLE patients.

Monocytes and neutrophils isolated from healthy donors were treated with anticardiolipin IgG isotype (ACA-IgG) and anti-dsDNA antibodies purified from APS and SLE patients’ serum, respectively, or with IgG from healthy donors (IgG -NHS). Levels of selected miRNAs and their target molecules were determined. Expression of proteins involved in miRNAs biogenesis (Drosha, Dicer, Ago-1, Ago-2 and 2, and Xpo-5) were further analyzed. Transfections were performed with precursors of the miRNAs found altered, to identify key target proteins in both pathologies.

Results:

The expression levels of the selected miRNAs in neutrophils were significantly lower in APS and SLE than in the control group. Accordingly, gene and protein expression levels of molecules related to miRNA biogenesis were reduced in neutrophils from APS and SLE. In monocytes, miR124a and -125a were low in APS and SLE patients, while miR-146a and miR-155 appeared elevated. Correlation studies showed, in both pathologies, that the altered expression of all selected miRNAs correlated with the disease activity index, and parameters related to autoimmunity, thrombosis, inflammation and oxidative stress. Association studies showed that the occurrence of thrombotic events and the presence of a pathological increase of carotid intima media thickness were also linked to the altered levels of the measured miRNAs. The expression levels of all miRNAs were significantly reduced in neutrophils treated with ACA-IgG and anti-dsDNA compared to those treated with IgG-NHS. Both autoantibodies also decreased  the expression of proteins related to miRNA biogenesis in these cells. In monocytes, treatment with ACA-IgG and anti-dsDNA significantly reduced the levels of miR-124a and miR-125b, as well as increased miR-146a and miR-155 expression. Monocyte transfections with pre-miR-124a and miR-125a, either separately or simultaneously, caused a drop in the expression of target molecules related to the atherothrombotic process in APS and SLE.

Conclusion: 1. Specific miRNAs might act as potential biomarkers of atherothrombosis in APS and SLE patients. 2. Some autoantibodies regulate this atherothrombotic status, at least partially, through epigenetic mechanisms such as modulation of miRNAs. Supported by CTS-7940, PI12/01511, SER.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/identification-and-characterization-of-micrornas-related-to-the-pathogenesis-of-cardiovascular-disease-in-patients-with-antiphospholipid-syndrome-and-systemic-lupus-erythematosus-role-of-specific-aut/