Inactivation of p38 kinase delays the onset of senescence in rabbit articular chondrocytes.

Replicative senescence limits cellular proliferation in vivo and in vitro. Recently, other groups and we reported that p38 kinase plays a key role on the onset of senescence. In this study, we demonstrated that replicative senescence can be delayed in rabbit chondrocytes in vitro by that p38 kinase inactivation.

Bcl-xL and E1B-19K proteins inhibit p53-induced irreversible growth arrest and senescence by preventing reactive oxygen species-dependent p38 activation.

In this study, we describe novel functions of the anti-apoptotic Bcl-2 family proteins. Bcl-x(L) and E1B-19K were found to inhibit p53-induced irreversible growth arrest and senescence, but not to inhibit transient growth arrest, implying that Bcl-x(L) and E1B-19K are specifically involved in senescence without participating in growth arrest. We provide several lines of evidences showing that the functions of Bcl-x(L) and E1B-19K to prevent generation of reactive oxygen species (ROS) are important to inhibit senescence induction.