Browsing by Author "Salminen, Ella"

The axolotl (Ambystoma mexicanum) has an astounding ability to regenerate entire lost body parts throughout its life. Significant progress has been made in recent years to understand the mechanisms of axolotl regeneration, but how the animal maintains its capacity for successful regeneration remains obscure. In mammals, the ability to repair damaged tissue drastically declines with age, in part due to the accumulation of senescent cells. However, in axolotls, the number of senescent cells does not increase upon aging. Low levels of chronic senescence in axolotls have been proposed to support their ability to regenerate even at an old age. Axolotls can efficiently clear senescent cells, but whether they can prevent the induction of senescence is not known. This thesis provides the first indication of a secreted anti-senescence activity from axolotl cells. Data presented here show that conditioned medium from cultured axolotl cells reduces senescence and increases proliferation in mouse embryonic fibroblast, a widely used model for spontaneous senescence. Remarkably, conditioned media from other tested cell types, namely cervical cancer cells and young mouse embryonic fibroblasts, did not considerably affect senescence, despite extensively increasing proliferation. Taken together, secreted factors from cultured axolotl cells seem to reduce senescence directly, and not by merely promoting proliferation. This observation forms a basis for future endeavors to determine whether preventing senescence facilitates regeneration in vivo.