Background MicroRNAs (miRNAs) are endogenous small non-coding RNAs that regulate gene expression by interfering translation or stability of target transcripts. This interplay between miRNA and their mRNA might constitute an important mechanism in the regulation of the proatherothrombotic status of SLE patients.
Objectives To investigate the contribution of deregulated miRNAs to the altered gene profile associated to cardiovascular disease in SLE.
Methods Thirty three SLE patients and 27 healthy donors were included in the study. Gene Expression Microarray (44K, Agilent, one colour) and nCounter microRNA Expression Array (NanoString Technologies) were performed, respectively, to analyze mRNA and miRNA expression profiles on isolated monocytes. Target genes of the differentially expressed miRNAs were identified by using the Igenuity Pathway Analysis Software (IPA). To recognize the putative microRNA-mRNA target pairs and interaction networks, the subsets of miRNAs and mRNAs were characterized by the microRNA Target Filter tool of IPA. The resulting identified interactions were revalidated by RT-PCR on the whole cohort of SLE patients. The predicted microRNA-mRNA interactions were also tested by functional analyses using microRNA over expression experiments in monocytes purified from SLE patients
Results Comparative analysis of the mRNA profiles showed significantly different expressions of 1222 genes in SLE monocytes in relation to healthy monocytes (658 up-regulated and 564 down-regulated). Functional analysis by using IPA showed that about 30% of altered genes were involved in inflammation and cardiovascular disease (CVD). Comparative analysis of the microRNA profiles showed significantly different expressions of 37 microRNAs in SLE monocytes (8 up-regulated and 29 down-regulated). Functional IPA analysis showed that microRNAs altered were mainly related to connective tissue disorders, inflammatory response and reproductive system disease. A total of 63 genes were inversely correlated, and predicted as CVD-related target genes of 23 differentially expressed microRNAs. Interaction networks of those genes and some microRNAs differentially expressed in SLE monocytes were also identified. Among them, we verified the overexpression of STAT3 and PPARg (which promote monocyte/macrophage differentiation and uptake of oxLDL) associated to inhibition of miR-130a-3p. Similarly, we demonstrated in our patients cohort the overexpression of CMKLR1 (chemokine receptor regulating the recruitment of inflammatory monocytes to sites of inflammation) associated with inhibition of miR-149–5p. The relationship between these identified target genes and specific miRNAs was further delineated in ex vivo studies.
Conclusions We have identified novel microRNA-mRNA regulatory networks related to CVD in SLE, thus delineating a novel genetic control of the diverse biological processes and factors related to the cardiovascular pathology present in this autoimmune condition.
Acknowledgement Supported by FIS (PI01333/2015) and CTS-7940.
Disclosure of Interest None declared