Chemical screen identifies a geroprotective role of quercetin in premature aging

Geng, Lingling; Liu, Zunpeng; Zhang, Weiqi; Li, Wei; Wu, Zeming; Wang, Wei; Ren, Ruotong; Su, Yao; Wang, Peichang; Sun, Liang; Ju, Zhenyu; Chan, Piu; Song, Moshi; Qu, Jing; Liu, Guang-Hui

Because Werner syndrome is caused by mutations in WRN gene that encodes a RecQ DNA helicase important to DNA replication and chromatin maintenance (Li et al., 2016b; Wu et al., 2018; Yu et al., 1996; Zhang et al., 2015) , genomic instability and heterochromatin disorganization manifest in WS pathogenesis (Li et al., 2016b; Murfuni et al., 2012; Ren et al., 2017a; Ren et al., 2011; Seki et al., 2008; Shamanna et al., 2017; Wu et al., 2018; Zhang et al., 2015) . Upon Que treatment, the transcription of pericentromeric repetitive sequences including α-satellite (α-Sat) and satellite 2 (Sat2) were downregulated, whereas nuclear envelope proteins Lamin B1 and LAP2β were transcriptionally upregulated (Fig. 5A) . Likewise, the protein levels of LAP2β and heterochromatin marker HP1γ were also increased ( Fig. 5B and 5C). Lastly, direct visualization of nuclear structure by transmission electron microscope (TEM) revealed . β-Actin was used as the loading control. Data are shown as mean ± SEM (n = 3). *P < 0.05 vs. Ctrl; **P < 0.01 vs. Ctrl. (C) Quantitative PCR analysis of telomere length of vehicle-and Que-treated WS hMSCs (passage 7). Data are shown as mean ± SEM (n = 3). *P < 0.05 vs. Ctrl. (D) Immunostaining of Ki67 in vehicle-and Que-treated WS hMSCs (passage 7), Scale bar, 25 μm. Data are shown as mean ± SEM (cell number ≥ 300). ***P < 0.001 vs. Ctrl. (E) Immunostaining of γ-H2AX and 53BP1 in vehicle-and Que-treated WS hMSCs (passage 7), Scale bar, 10 μm. The percentage of γ-H2AX/53BP1-double positive cells are shown as mean ± SEM (cell number ≥ 300). *P < 0.05 vs. Ctrl. (F) FACS measurement of reactive oxygen species (ROS) by H2DCFDA in vehicle-and Que-treated WS hMSCs (passage 7). a.u., arbitrary unit. (G) RT-qPCR analysis of IL6 mRNA levels in vehicle-and Que-treated WS hMSCs (passage 7). Data are shown as mean ± SEM (n = 3). ***P < 0.001 vs. Ctrl. (H) Cell apoptosis assay in vehicle-and Que-treated WS hMSCs (passage 7). Quantitative data on the right are presented as mean ± SEM (n = 3). ***P < 0.001 vs. Ctrl.