High glucose promotes cellular senescense in the kidney by inducing a mild hyperosmolar stress

MARÍA DEL NOGAL; NURIA TROYANO; JOSE LUIS CANO-PEÑALVER; M. ALICIA CORTÉS; GEMMA OLMOS; SERGIO DE FRUTOS; MANUEL RODRIGUEZ-PUYOL; MARIA P. RUIZ-TORRES

San Diego

Congreso; Kidney Week ASN; 2012

American Society of Nefrology (ASN)

Background: Senescence is a stress response that withdraws the cell cycle and leads to morphological and functional cellular changes. Senescence appears in aged and diabetic kidney suggesting an important role on kidney dysfunction. Our aim was to analyze the role of the extracellular osmolarity induced by high glucose in human mesangial and rat kidney cellular senescence and the mechanism involved. Methods: In order to increase extracellular osmolarity, Human mesangial cells (HMC) or Ex vivo rat kidney slices were treated with high glucose (HG) or the control osmolyte mannitol during different periods of time. Male Wistar rats were treated with mannitol, with streptozotocin to induce experimental diabetes or with vehicle. Cellular senescence was measured as β-galactosidase activity using a fluorescent substrate. p53, p21, p16 and Ras expression were measured by immunoblotting and immunohistochemistry. Ras activation was analyzed by pull down assay. Reactive oxygen species (ROS) production was evaluated by flow cytometry. Results: Both HG and mannitol mildly increased extracellular osmolarity in HMC promoting cellular senescence by increasing p53, p21 and p16 protein expression. Both HG and Mannitol promoted an increase in reactive oxygen (ROS) production and the constitutive activation of Ras, however the inhibition of ROS and Ras prevented cellular senescence. Both streptozotocin and mannitol rats shown serum osmolarity and p53 and p16 protein expression increase compared with controls. Both HG- or mannitol-treated rat kidney slices shown increased p53 and p16 expression. Conclusions: HG induced cellular senescence in HMC and rat kidney cortex by inducing extracellular osmolarity increase, since the control osmolyte mannitol reproduced the same results. This effect was ROS and Ras dependent.Funding: Government Support - Non-U.S.Course: Annual Meeting: Abstract SessionsSession: Publication Only Abstracts