title: Absence of replicative senescence in cultured cells from the short-lived killifish Nothobranchius furzeri.
abstract: A major challenge in age research is the absence of short-lived vertebrate model organisms. The turquoise killifish Nothobranchius furzeri has the shortest known lifespan of a vertebrate that can be bred in captivity. The short lived GRZ strain only reaches a maximum age of 3-4 months, whereas other strains (MZM) reach 6-10 months. Most importantly, the short lifespan is associated with typical signs of ageing. To find out more about possible cellular factors that might contribute to the short lifespan and to the difference in lifespan between strains, we analyzed the expression of markers for cellular senescence. Expression of Tp53, Cdkn1a and Cdkn2a/b in skin revealed no change in the short-lived GRZ but increased expression of the cell cycle inhibitors Cdkn1a and Cdkn2a/b in the long-lived MZM strain with age. This suggests that expression of distinct cell cycle inhibitors reflects rather chronological than biological age in N. furzeri. To study the relationship of organismal life span and in vitro life span of cells, we established a primary cell culture model. For both strains we demonstrate here the absence of replicative senescence as analysed by morphology, expression of Cdkn1a and Cdkn2a/b, population doubling times and γH2AFX in long-term and short-term cultured cells. We reason this to be on account of sustained telomerase activity and maintained telomeric length. Hence, we propose that differences in maximum life span of different N. furzeri strains is not reflected by differences in proliferation speed or replicative potential of the respective cultured cells.
authors.affiliation: Molecular Genetics, Leibniz Institute for Age Research, Fritz Lipmann Institute, Beutenbergstr. 11, 07745 Jena, Germany. graf@zeiss.de
authors.forename: Michael
authors.initials: M
authors.lastname: Graf
authors.forename: Nils
authors.initials: N
authors.lastname: Hartmann
authors.forename: Kathrin
authors.initials: K
authors.lastname: Reichwald
authors.forename: Christoph
authors.initials: C
authors.lastname: Englert
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D059447:Cell Cycle Checkpoints / Q000528:radiation effects; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics; D049109:Cell Proliferation; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000235:genetics / Q000502:physiology*; D050762:Cyclin-Dependent Kinase Inhibitor p15 / Q000096:biosynthesis / Q000235:genetics; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000096:biosynthesis / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000096:biosynthesis / Q000235:genetics; D005720:Gamma Rays; D005786:Gene Expression Regulation / Q000502:physiology; D006657:Histones / Q000235:genetics; D007695:Killifishes / Q000145:classification / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008136:Longevity / Q000502:physiology; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D012867:Skin / Q000378:metabolism; D013045:Species Specificity; D019098:Telomerase / Q000096:biosynthesis; D059505:Telomere Homeostasis
chemical_list: D018797:Cell Cycle Proteins; D050762:Cyclin-Dependent Kinase Inhibitor p15; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; C468783:H2AX protein, human; D006657:Histones; D019098:Telomerase