The olive constituent oleuropein exhibits proteasome stimulatory properties in vitro and confers life span extension of human embryonic fibroblasts.
Normal human fibroblasts undergo replicative senescence due to both genetic and environmental factors. Senescence and aging can be further accelerated by exposure of cells to a variety of oxidative agents that contribute among other effects to the accumulation of damaged proteins. The proteasome, a multicatalytic nonlysosomal protease, has impaired function during aging, while its increased expression delays senescence in human fibroblasts. The aim of this study was to identify natural compounds that enhance proteasome activity and exhibit antiaging properties. We demonstrate that oleuropein, the major constituent of Olea europea leaf extract, olive oil and olives, enhances the proteasome activities in vitro stronger than other known chemical activators, possibly through conformational changes of the proteasome. Moreover, continuous treatment of early passage human embryonic fibroblasts with oleuropein decreases the intracellular levels of reactive oxygen species (ROS), reduces the amount of oxidized proteins through increased proteasome-mediated degradation rates and retains proteasome function during replicative senescence. Importantly, oleuropein-treated cultures exhibit a delay in the appearance of senescence morphology and their life span is extended by approximately 15%. In summary, these data demonstrate the beneficial effect of oleuropein on human fibroblasts undergoing replicative senescence and provide new insights towards enhancement of cellular antioxidant mechanisms by natural compounds that can be easily up-taken through normal diet.
Katsiki
Magda
M
Institute of Biological Research and Biotechnology, Laboratory of Molecular and Cellular Aging, National Hellenic Research Foundation, Athens, Greece.
Chondrogianni
Niki
N
Chinou
Ioanna
I
Rivett
A Jennifer
AJ
Gonos
Efstathios S
ES
D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D002460:Cell Line; D016922:Cellular Senescence / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D020536:Enzyme Activators / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D066298:In Vitro Techniques; D057888:Iridoid Glucosides; D039823:Iridoids; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011487:Protein Conformation; D011714:Pyrans / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
D000975:Antioxidants; D020536:Enzyme Activators; D057888:Iridoid Glucosides; D039823:Iridoids; D016877:Oxidants; D010936:Plant Extracts; D011714:Pyrans; D017382:Reactive Oxygen Species; C002769:oleuropein; D046988:Proteasome Endopeptidase Complex