Resveratrol blocks retrotransposition of LINE-1 through PPAR α and sirtuin-6

The retroelement long interspersed element-1 (LINE-1 or L1) comprises about 17% of the human genome. L1 retrotransposition is known to cause genomic instability and related disorders, and resveratrol suppresses this retrotransposition; however, the underlying mechanism is still not elucidated. Recent observations showed that low-molecular-weight compounds might induce L1 retrotransposition through unknown mechanisms. This study aimed to determine polyphenol resveratrol (RV)’s effect on L1-RTP (retrotransposition) in somatic cells. Surprisingly, RV completely blocked L1-RTP. Experiments using the PPARα inhibitor GW6471 or siRNA-mediated PPARα depletion showed that RV-mediated L1-RTP’s inhibition depended on peroxisome proliferator-activated receptor α (PPARα). We demonstrated that RV inhibits p38 and cAMP response element binding protein phosphorylation, which are involved in MAPK signaling, and the L1-ORF1 protein’s chromatin recruitment. Furthermore, RV increased the expression of sirtuin-6 (SIRT6), which inhibited the activation of L1. The sirtuins family, SIRT1, SIRT6, and SIRT7, but not SIRT3, are involved in RV-mediated inhibition of L1-RTP. Overall, our findings suggest that RV directly modulates PPARα-mediated L1-RTP in somatic cells and that MAPK signaling interacts with SIRT6 closely and may play a role in preventing human diseases such as cancer.


Supplementary Figure S2
Supplementary Figure S4 RV -mediated SIRT6 expression depends on PPARα. RV treatment increased the level of SIRT6 expression in HeLa cells. WB analysis was performed after introducing either control siRNA or PPARα siRNA-1, 2. The cells were treated with 0.02% DMSO (D) or 20 μM RV (R) for 2 days. The relative intensity ± SD is depicted. The effects of PPARα siRNAs were significant (p < 0.05). Asterisks indicate statistical significance (p < 0.05 compared to control siRNA in RV treatment).
Supplementary Figure S5 Raw data blots (a) and normalized blot (b) used in Fig. 1G. The arrowhead indicates the band used in the study. The blot image represents the extracted lane of the target sample.
Supplementary Figure S6 Raw data blots (a, c, e) and normalized blot (b, d, f) used in Fig. 2E (a, b), 2F (c, d), and 2G (e, f). The arrowhead indicates the band used in the study. ORF1 and GAPDH were detected on the same membrane because ORF1 has protein A attached to its C-terminal, which can be detected by IgG (e and f).

Supplementary Figure S7
Raw data blots (a, c) and normalized blot (b, d) used in Fig. 3B (a, b) and 3C (c, d). The arrowhead indicates the band used in the study. The blot image represents the extracted lane of the target samples (a, b).

Supplementary Figure S8
Raw data blots (a, c) and normalized blot (b, d) used in Fig. 3D (a, b) and 3E (c, d). The arrowhead indicates the band used in the study. ORF1 and SIRT6 or ORF1 and GAPDH were detected on the same membrane because ORF1 has protein A attached to its C-terminal, which can be detected by IgG (a, b). D was used for Figure 3E. The blot image represents the extracted lane of the target samples (a, b).

Supplementary Figure S9
Raw data blots (a, c, e) and normalized blot (b, d, f) used in Fig. 4A (a, b), 4C (c, d), and 4E (e, f). The arrowhead indicates the band used in the study.The blot image represents the extracted lane of the target samples (a, b, e and f).