High cholesterol levels have been linked to a high risk of cardiovascular diseases, and preventative pharmacological care to lower cholesterol levels is critically important. Statins, which are hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, are drugs used to reduce the endogenous cholesterol synthesis, thus minimizing its pathophysiological effects. Despite the proven benefits, statins therapy is known to cause a number of skeletal muscle disorders, including myalgia, myopathy and myositis. The mechanisms underlying such statin-induced side effects are unknown. Recently, a group of genes and molecular pathways has been described to participate in statin-induced myopathy, caused by either simvastatin or rosuvastatin, although the mechanism by which changes in gene regulation occur was not studied. Transposable Elements (TEs), repetitive elements that move within the genome, are known to play regulatory roles in gene expression; however, their role in statin-induced muscle damage has not been studied. We analyzed the expression of TEs in human skeletal fiber cells treated with either simvastatin or rosuvastatin, as well as their respective controls, and identified TEs that change their expression in response to the treatment. We found that simvastatin resulted in >1000 differentially expressed (DE) TEs, whereas rosuvastatin resulted in only 27 DE TEs. Using network analysis tools, we predicted the impact of the DE TEs on the expression of genes and found that amongst the genes potentially modulated by TEs, there are some previously associated to statin-linked myopathy pathways (e.g., AKT3). Overall, our results indicate that TEs may be a key player in the statin-induced muscle side effects.

High cholesterol levels have been associated with cardiovascular diseases, and lowering them has been a key focus in the treatment of such diseases. Statins are drugs used with that aim, and can be divided in the lipophilic Simvastatin and the hydrophilic Rosuvastatin. Regardless of the statin type, a high proportion (∼70%) of patients stop using statins due to suffering from side effects on skeletal muscle, such as myalgia, and muscle cramps. Thus, there has been a considerable effort in understanding how statins contribute to these side effects. A catalogue of genes and molecular pathways that change upon statin treatment has been recently published, allowing further understanding how the side effects occur. However, Transposable Elements (TEs) were not studied. TEs can move within a genome, and they are highly repetitive, representing about half of the human genome. Currently, most TEs in the human genome are inactive, but it has been shown that TEs can still transcribe, and that either via their transposition or their transcriptional activity, can influence gene expression. Here, using novel computational tools to accurately estimate TE expression, we studied their activity and predicted their potential impact on gene expression. We developed a catalogue of TEs expressed upon statin treatment, and the putative genes whose expression might be influenced by TEs. Overall, we speculate that based on our findings, TEs might be a key target in order to understand statin-mediated side effects.