Mitochondrial impairment promotes cellular senescence in human neural stem cells

NIEVAS, MICAELA; QUEVEDO PROL, SOL; MUCCI, SOFÍA; RODRÍGUEZ VARELA, MARÍA SOLEDAD; ROMORINI, LEONARDO; SCASSA, MARÍA ELIDA; SEVLEVER, GUSTAVO EMILIO; MARAZITA, MARIELA

Cold Spring Harbor

Congreso; Cold Spring Harbor meeting: Neurodegenerative Diseases: Biology & Therapeutics; 2022; 2022

Cold Spring Harbor Laboratory

Cellular senescence has emerged as a driver of multiple age-related pathologies through the senescence-associated secretory phenotype. This state may be triggered by a myriad of stressors including mitochondrial dysfunction. The decline in mitochondrial function and the consequent increase in reactive oxidative species (ROS) are key features of neurodegenerative pathologies. In particular, age-associated alterations in mitochondrial function are thought to have a profound effect on neural stem cells (NSC) properties. The aim of this work was to test the effect of mitochondrial impairment on the induction of cellular senescence in a model of human NSCs. Mitochondrial dysfunction may be experimentally achieved by rotenone (ROT) which impairs mitochondrial respiration by inhibiting electron transport chain complex I, leading to ATP depletion, ROS production and loss of mitochondrial membrane potential. First, Human embryonic stem cell-derived NSCs were exposed for 72 h to a ROT dose-response curve. Cell viability was assessed by flow cytometry with propidium iodide staining. To generate a low grade chronic damage the highest concentration that did not impact cell viability was chosen for further experiments. Twelve days after the initial damage morphological analysis showed an increase in a flat enlarged morphology typical of senescent cells. ROT treatment led to a decrease in the proliferation rate and showed an enhanced senescence-associated β-galactosidase activity. Immunofluorescence microscopy assays revealed a change in the expression of NSCs and neurons lineage defining markers. We conclude that mitochondrial dysfunction disturbs proliferation, stemness and leads to a senescent phenotype in human NSCs. Elucidating mitochondrial-induced damage is key for understanding mechanisms underlying neurodegeneration, and will help identify novel therapeutic targets to restore neurological function.