PhD Student University of Innsbruck Innsbruck, United States
Abstract: Aging is a complex process characterized by the progressive accumulation of molecular and cellular damage, driving functional decline and neurodegenerative disorders. Investigating human brain aging is challenging due to limited access to biomaterials and the inability of induced pluripotent stem cells (iPSCs) to retain age-related signatures post-reprogramming. To address this, we developed GFP-T2A-PROG, an iPSC line enabling inducible overexpression of Progerin, a mutant Lamin A protein linked to premature aging. This model allows controlled induction of aging phenotypes in neural lineages, particularly cortical organoids. Progerin overexpression in neurons and organoids recapitulated key aging hallmarks, including nuclear lamina abnormalities, a 40% reduction in H3K9me3 and HP1γ-marked heterochromatin, DNA damage accumulation indicated by γH2AX and p53BP1, elevated senescence-associated β-galactosidase activity, and increased p21. Furthermore, artificially aged models showed a 2-fold increase in mitochondrial reactive oxygen species (ROS) and glycolysis, suggesting metabolic dysfunctions previously implicated in aging. Transcriptomic analysis validated the age-associated phenotype observed at the cellular level, identifying 1,366 differentially expressed genes. We found, among others, upregulation of STAT3 and the metabolic gene PYCR1 and downregulation of mitochondrial genes OPA1 and TOMM20. We corroborated observations from post-mortem aged human brain tissue and Alzheimer’s disease (AD) pathology, such as reduced expression of synaptic genes (SYN1, SNAP25, and CAMK4). Initial single-cell transcriptomic data suggest an imbalance in synaptic gene expression, which will be further explored through functional network analyses. Finally, we collected evidence highlighting the potential of GFP-T2A-PROG organoids for studying rejuvenation, in particular through reversal of DNA damage upon application of rapamycin. In summary, this model provides a robust platform for investigating cellular aging processes underlying neural dysfunction, including disrupted mitochondrial homeostasis and synaptic aberrations, and offers significant potential for developing age-reversal strategies and modeling neurodegenerative diseases.
