Small noncoding RNAs and their chemical modifications in cardiovascular disease

RNA transcripts are not finished products.

Besides well-known processing steps like splicing, capping and polyadenylation, RNAs undergo chemical modifications at individual nucleotide level.

The collective of these RNA posttranscriptional modifications (R-PTMs), the epitranscriptome, is subject of extensive studies regarding longer RNA species. However, the small RNA (i.e. microRNAs, snoRNAs, tRNAs, etc.) epitranscriptome remains dramatically understudied.

My group has shown that the small RNA transcriptome responds rapidly to ischemia, a key stressor in cardiovascular disease.

Changes in modifications of small RNAs alter their function and contribute to tissue reperfusion and recovery via increased angiogenesis.

However, we do not know if, and if so, what role the small RNA epitranscriptome plays in the initiation and progression of atherosclerosis, the underlying cause of most cardiovascular diseases. Here, I aim to investigate the role of the small RNA epitranscriptome in the development of atherosclerosis.

For this, we will make use of 2 atherosclerosis mouse models to obtain early, progressing and advanced stable lesions, as well as advanced, unstable lesions.

We will validate our findings, using both asymptomatic and symptomatic human carotid artery plaques obtained during endarterectomy surgery.

Sequence-altering modifications (A-to-I-editing, C-to-U-editing, isomiRs) will be detected by small RNA-Sequencing (sRNA-Seq), whereas different forms of methylated RNAs (m1A, m6A, m5C, m7G and 2’Ome) will be pulled-down using immunoprecipitation prior to sRNA-Seq.

Functionality of selected SR-PTMs will be investigated using in vitro and ex vivo models, depending on cell-type specific expression, established by variant-specific rt-qPCR methods, RNA-IP followed by qPCR, RTL-Q and in situ hybridisation.