Fig. 4: Glycerol-3-P accumulation at the onset of senescence metabolic reprogramming.
a, Nodes with the highest betweenness values (top 20; Supplementary Table 9) in the gene–metabolite correlation network connecting genes and metabolites presenting a correlation with an absolute value >0.5 for RAS OIS and RAF OIS, etoposide-mediated DDIS, RS and Q. MYO9A, myosin 9-A; SCN9A, sodium voltage-gated channel α subunit 9; HMGN2, high mobility group nucleosomal binding domain 2; DARS2, aspartyl-tRNA synthetase 2, mitochondrial; FAM43A, family with sequence similarity 43 member A; HEG1, heart development protein with EGF-like domains 1; PAPPA, pappalysin 1; GCC2, GRIP and coiled-coil domain containing 2. b, Reactome analysis of genes correlating either positively or negatively with G3P accumulation during senescence in WI38 fibroblasts. c, Simplified scheme of the metabolic pathways involving G3P. d, Heat maps representing levels of indicated lipid species in WI38 fibroblasts proliferating (n = 5), undergoing DDIS (n = 5) or RS (n = 4). PC, phosphatidylcholine; PE, phosphatidylethanolamine; PI, phosphatidylinositol; PS, phosphatidylserine; PG, phosphatidylglycerol; FC, fold change. e, Ratio of total PL to TAG levels normalized to protein content in proliferative WI38 fibroblasts compared to DDIS (n = 5) or RS (n = 4) cells. f, Immunoblots showing indicated protein levels in WI38 fibroblasts undergoing RAS OIS (left) or DDIS (right). Sample processing controls (actin) were migrated into different gels from those of GK. g, Densitometric quantification of GK and p21 protein levels relative to actin from three experiments, including the one shown in panel (f), in RAS OIS (day 7) and DDIS (day 6). h, Western blots showing indicated protein levels in extracts from WI38 fibroblasts proliferating or undergoing DDIS and non-transfected (−) or transfected with a control non-silencing siRNA (siCtrl) or an siRNA targeting the p53 mRNA (si p53) for 4 days. The experiment was repeated independently twice with similar results. In e,g, data are presented as mean ± s.d. Indicated P values were calculated using an unpaired two-sided Student’s t-test.
