Biology subjects

Urrutia, G. A.

Publications and source records attributed to Urrutia, G. A..

4 recordsLinked to original sources

bioRxiv2025

A single factor for safer cellular rejuvenation

Ageing is a key driver of the major diseases afflicting the modern world. Slowing or reversing the ageing process would therefore drive significant and broad benefits to human health. Previously, the Yamanaka factors (OCT4, SOX2, KLF4, with or without c-MYC: OSK(M)) have been shown to rejuvenate cells based on accurate predictors of age known as epigenetic clocks. Unfortunately, OSK(M) induces dangerous pluripotency pathways, making it unsuitable for therapeutic use. To overcome this therapeutic barrier, we screened for novel factors by optimising directly for age reversal rather than for pluripotency. We trained a transcriptomic ageing clock, unhindered by the low throughput of bulk DNA methylation assays, to enable a screen of unprecedented scale and granularity. Our platform identified SB000, the first single gene intervention to rejuvenate cells from multiple germ layers with efficacy rivalling the Yamanaka factors. Cells rejuvenated by SB000 retain their somatic identity, without evidence of pluripotency or loss of function. These results reveal that decoupling pluripotency from cell rejuvenation does not remove the ability to rejuvenate multiple cell types. This discovery paves the way for cell rejuvenation therapeutics that can be broadly applied across age-driven diseases. HighlightsO_LISB000 drives multi-omic rejuvenation in human fibroblasts, as evidenced by substantial reversal of numerous epigenetic clocks, lowered single-cell transcriptomic age, and decreased senescence-associated gene expression. C_LIO_LIIn contrast to OSK(M), SB000 treatment maintains transcriptomic and functional measures of fibroblast identity without the activation of pluripotency. C_LIO_LISB000 rejuvenation generalises to keratinocytes, cells from another germ layer, with potency matching or surpassing OSK(M). C_LI

cell biology↗

bioRxiv2024

A human neuronal model of sporadic Alzheimer's disease induced by FBXO2 downregulation shows A β aggregation, tau hyperphosphorylation and functional network impairment

Sporadic Alzheimers disease (sAD) arises from a complex interplay between genetic and environmental factors that remains poorly understood, making it challenging to develop accurate cell models. To address this problem, by hypothesing that the early disease sAD states can be characterised by transcriptomic fingerprints, we assessed the effect on A{beta} aggregation in human neuroblastoma cells a set of genes obtained by analysing snRNA-seq data from post-mortem AD patients. We then validated the most effective genes in human iPSC-derived cortical neurons, and selected FBXO2, a gene encoding a subunit of the ubiquitin protein ligase complex SCF, for further analysis. We found that early downregulation of FBXO2 in human iPSC-derived cortical neurons resulted in A{beta} aggregation, tau hyperphosphorylation, and structural and functional neuronal network impairment. Based on these results, we report a neuronal sAD model (FBXO2 KD sAD) that recapitulates a set of molecular hallmarks of sAD. We suggest that this strategy can be expanded towards the generation of panels of preclinical stem cell-derived models that recapitulate the molecular complexity of the broad spectrum of AD patients.

neuroscience↗

bioRxiv2024

In situ generation of Aβ42 oligomers via secondary nucleation triggers neurite degeneration and synaptic dysfunction in human iPSC-derived glutamatergic neurons

The aggregation of A{beta}42 into misfolded oligomers is a central event in the pathogenesis of Alzheimers disease. In this study, we aimed to develop a robust experimental system that recapitulates A{beta}42 oligomerization in living cells to gain insight into their neurotoxicity and to provide a platform to characterize the effects of inhibitors of this process. Our strategy is based on the in situ generation of A{beta}42 oligomers via secondary nucleation by repeatedly treating the cells with A{beta}42 monomers in the presence of pre-formed A{beta}42 fibrils. This approach enables an accurate control over the levels of on-pathway soluble A{beta}42 oligomers and cell-associated aggregates, as well as the study of their neurotoxic effects. By implementing this approach in human glutamatergic neurons derived from induced pluripotent stem cells (iPSCs), we were able to replicate key aspects of Alzheimers disease, including neurite degeneration and synaptic dysfunction. Using BRICHOS, a molecular chaperone that specifically inhibits secondary nucleation, we confirmed that aggregation in this system occurs through secondary nucleation, and that quantitative parameters for comparing potential A{beta}42 aggregation inhibitors can be obtained. Overall, our results demonstrate that by in situ generation of on-pathway A{beta}42 oligomers, one can obtain translational cellular models of AD to bridge the gap between basic research and clinical applications.

cell biology↗

bioRxiv2024

TNFα-driven Aβ aggregation, synaptic dysfunction and hypermetabolism in human iPSC-derived cortical neurons

Alzheimers disease (AD) patients exhibit an increased load of A{beta} aggregates in the brain parenchyma. The neurotoxic nature of these aggregates has been underscored by recent advances in therapies aimed at reducing their load. To make further progress towards the development of increasingly effective treatments, there is a still largely unmet need for reliable cell models that comprehensively recapitulate aggregate-driven AD pathology. Here, we report a robust and scalable pipeline for generating human iPSC-derived cortical neurons that display A{beta} aggregates in their axonal projections. This phenotype is caused by a repeated dosage of tumour necrosis factor-alpha (TNF) to simulate the chronic inflammatory environment characteristic of AD and enhanced in neurons carrying the Swedish mutation. In association with the increased A{beta} deposits in the cell bodies, this cell model exhibits other key hallmarks of AD, including structural alterations of synapses, electrophysiological asynchronous hyperactivity, and hypermetabolism. Overall, these results illustrate how repeated TNF treatment models central aspects of AD pathology, and provides a platform that could be used for facilitating the translation of potential drugs to clinical applications.

cell biology↗