Haendeler Judith, Hoffmann Jörg, Diehl J Florian, Vasa Mariuca, Spyridopoulos Ioakim, Zeiher Andreas M, Dimmeler Stefanie
Molecular Cardiology, Department of Internal Medicine IV, University of Frankfurt, Frankfurt, Germany.
Circ Res. 2004 Apr 2;94(6):768-75. doi: 10.1161/01.RES.0000121104.05977.F3. Epub 2004 Feb 12.
Aging is associated with a rise in intracellular reactive oxygen species (ROS) and a loss of telomerase reverse transcriptase activity. Incubation with H2O2 induced the nuclear export of telomerase reverse transcriptase (TERT) into the cytosol in a Src-family kinase-dependent manner. Therefore, we investigated the hypothesis that age-related increase in reactive oxygen species (ROS) may induce the nuclear export of TERT and contribute to endothelial cell senescence. Continuous cultivation of endothelial cells resulted in an increased endogenous formation of ROS starting after 29 population doublings (PDL). This increase was accompanied by mitochondrial DNA damage and preceded the onset of replicative senescence at PDL 37. Along with the enhanced formation of ROS, we detected an export of nuclear TERT protein from the nucleus into the cytoplasm and an activation of the Src-kinase. Moreover, the induction of premature senescence by low concentrations of H2O2 was completely blocked with the Src-family kinase inhibitor PP2, suggesting a crucial role for Src-family kinases in the induction of endothelial cell aging. Incubation with the antioxidant N-acetylcysteine, from PDL 26, reduced the intracellular ROS formation and prevented mitochondrial DNA damage. Likewise, nuclear export of TERT protein, loss in the overall TERT activity, and the onset of replicative senescence were delayed by incubation with N-acetylcysteine. Low doses of the statin, atorvastatin (0.1 micromol/L), had also effects similar to those of N-acetylcysteine. We conclude that both antioxidants and statins can delay the onset of replicative senescence by counteracting the increased ROS production linked to aging of endothelial cells.
衰老与细胞内活性氧（ROS）水平升高以及端粒酶逆转录酶活性丧失有关。用H2O2孵育可诱导端粒酶逆转录酶（TERT）以Src家族激酶依赖的方式从细胞核输出到细胞质中。因此，我们研究了以下假设：与年龄相关的活性氧（ROS）增加可能诱导TERT的核输出并导致内皮细胞衰老。内皮细胞的连续培养导致在29次群体倍增（PDL）后内源性ROS形成增加。这种增加伴随着线粒体DNA损伤，并在PDL 37时复制性衰老开始之前出现。随着ROS形成的增强，我们检测到核TERT蛋白从细胞核输出到细胞质中以及Src激酶的激活。此外，低浓度H2O2诱导的过早衰老被Src家族激酶抑制剂PP2完全阻断，这表明Src家族激酶在内皮细胞衰老诱导中起关键作用。从PDL 26开始用抗氧化剂N-乙酰半胱氨酸孵育可减少细胞内ROS形成并防止线粒体DNA损伤。同样，用N-乙酰半胱氨酸孵育可延迟TERT蛋白的核输出、总TERT活性的丧失以及复制性衰老的开始。低剂量的他汀类药物阿托伐他汀（0.1微摩尔/升）也具有与N-乙酰半胱氨酸类似的作用。我们得出结论，抗氧化剂和他汀类药物均可通过抵消与内皮细胞衰老相关的ROS产生增加来延迟复制性衰老的开始。
