Fig. 4 |. CXCL9 is an important regulator of endothelial cell aging.
a, Quantitative PCR data show increased expression of CXCL9 in BECs of older individuals compared to younger individuals (P = 0.0075). b, Significant differences in tube formation capacity are observed in BECs from older and younger individuals (P = 0.0323). c, Quantification of NO production shows impaired capacity of BECs from older individuals to produce NO when compared to younger individuals in response to acetylcholine (Ach) (adjusted P value (Padj) of BECs (young) versus BECs (old), P <0.0001; Padj value of BECs (young) Ach versus BECs (old) Ach, 0.0002). d, Quantification of LDL uptake show impaired capacity of BECs from older individuals to uptake Ac-LDL when compared to younger individuals (Padj = 0.0002). e–g, Quantification of number of tubes, LDL uptake and NO production in response to Ach in Scramble and CXCL9-KD iPSC-ECs shows a significant improvement in aging phenotypes in ECs at passage 6 and 8 with silencing of the CXCL9 gene. Padj values for P6 (Scramble) versus P6 (CXCL9 shRNA) = 0.008 (e); P8 (Scramble) versus P8 (CXCL9 shRNA) = 0.0475. Padj values for P6 (Scramble) versus P6 (CXCL9 shRNA) = 0.044; P8 (Scramble) versus P8 (CXCL9 shRNA) = 0.001 (f). Padj values for P6 (Scramble) Ach versus P6 (CXCL9-KD) Ach = 0.0116; P8 (Scramble) Ach versus P8 (CXCL9-KD) Ach = 0.0001 (g). Scramble are hiPSCs infected with lentivirus carrying nonsense-sequence shRNA. CXCL9-KD are hiPSCs infected with lentivirus carrying sequence-specific shRNA to knockdown expression of CXCL9. All data are represented as mean ± s.e.m., n = 3, *P < 0.05, **P < 0.01, ***P < 0.001; ****P < 0.0001; NS, not significant. Statistical analyses were performed using Student’s t-test or one-way ANOVA corrected with the Bonferroni method.