Introduction:

SARS-CoV-2 triggered pandemic has emerged as a dangerous infectious disease that most commonly acts as a respiratory illness. Side effects on other organ-systems such as the myocardium are often neglected. Clinical studies have shown that an infection with SARS-CoV-2 can lead to cardiac inflammation. ACE2 and TMPRSS2 are important entry points for the virus. We herein investigated for a non-coding (miRNA) RNA-based regulatory mechanism repressing ACE2 and TMPRSS2. We identified miRNA-362-5p in silico and tested miRNA modulation in various in vitro and ex vivo model systems.

Methods and Results:

Applying multi-modal in silico analysis of human ACE2 and TMPRSS2 3´-UTR, we identified miRNA-362-5p as a potential terminator of ACE2/TMPRSS2 expression. We validated this finding in a miRNA reporter gene assay. At cellular signalling level we did not find any evidence for regulation of inflammatory NF-κB-signalling via miRNA-362-5p. These findings were translated into a model of ex vivo cultured living myocardial slices (LMS). In brief, fresh hearts were cut and trimmed into 300 μm thick LMS and then cultured for 24h with direct application of miR-362-5p into the medium (different dosings of 3nM and 30nM). qPCR-based miRNA detection revealed therapeutic overexpression of miRNA-362-5p.

Conclusion:

In summary, we report the in silico prediction and in vitro validation of miR-362-5p as a potent post-transcriptional regulator of ACE2 and TMPRSS2. Given the potential of cardio-inflammatory side effects caused by SARS-CoV-2 infection, we established a miRNA-based model-system in ex vivo LMS. These findings may lead to the development of novel RNA-based therapeutics counteracting SARS-CoV-2 viral entry.