Carling, P. | Search bioRxiv

bioRxiv2025

TFEB and TFE3 have cell-type specific expression in the brain and divergent roles in neurons

Lysosomal dysfunction occurs in many neurodegenerative diseases, including Parkinsons disease, and activating TFEB to enhance lysosomal biogenesis is a promising therapeutic strategy. To understand TFEB physiology in cells of the brain, we characterised TFEB expression using iPSC-derived models, and transcriptomic analysis of human and mouse brain tissue. Surprisingly, TFEB expression at the RNA and protein level was restricted to glia, whereas the related transcription factor, TFE3, was expressed ubiquitously. We identified HDAC1/2/3 as transcriptional repressors of neuronal TFEB and found the brain-penetrant HDAC inhibitor ACY-738 derepressed TFEB expression and enhanced TFE3 nuclear translocation in iPSC-dopaminergic neurons (iPSC-DaNs). We delineated the role of each transcription factor by genetic manipulation in iPSC-DaNs to reveal divergent roles in which TFEB activates mitochondrial biogenesis, whereas TFE3 enhances lysosomal biogenesis. Finally, we show TFE3 activation corrects the lysosomal dysfunction associated with GBA-N370S and SNCA-Triplication mutations in Parkinsons patient-derived iPSC-DaNs, demonstrating therapeutic utility in neurodegeneration.

cell biology↗

bioRxiv2022

Tau depletion in human neurons mitigates A beta-driven toxicity

BackgroundAlzheimers disease (AD) is an age-related neurodegenerative condition and the most common type of dementia, characterised by pathological accumulation of extracellular plaques and intracellular neurofibrillary tangles that mainly consist of amyloid-{beta} (A{beta}) and hyperphosphorylated tau aggregates, respectively. Previous studies in mouse models with a targeted knock-out of the microtubule-associated protein tau (Mapt) gene demonstrated that A{beta}-driven toxicity is tau-dependent. However, human cellular models with chronic tau lowering remain unstudied. MethodsIn this study, we generated stable tau-depleted human induced pluripotent stem cell (iPSC) isogenic panels from two healthy individuals using CRISPR-Cas9 technology. We then differentiated these iPSCs into cortical neurons in vitro in co-culture with primary rat cortical astrocytes before conducting electrophysiological and imaging experiments for a wide range of disease-relevant phenotypes. Both AD brain derived and recombinant A{beta} were used in this study to elicit toxic responses from the iPSC- derived cortical neurons. ResultsWe showed that tau depletion in human iPSC-derived cortical neurons caused considerable reductions in neuronal activity without affecting synaptic density. We also observed neurite outgrowth impairments in two of the tau-depleted lines used. We found axonal transport of mitochondria, mitochondrial function, and cortical neuron differentiation propensity remained unaffected regardless of tau expression levels. Finally, tau depletion protected neurons from adverse effects mitigating the impact of exogenous A{beta}-induced hyperactivity, deficits in retrograde axonal transport of mitochondria, and neurodegeneration. ConclusionsOur study established stable human iPSC isogenic panels with chronic tau depletion from two healthy individuals. Cortical neurons derived from these iPSC lines showed that tau is essential in A{beta}-driven hyperactivity, axonal transport deficits, and neurodegeneration, consistent with studies conducted in Mapt-/- mouse models. These findings highlight the protective effects of chronic tau lowering strategies in AD pathogenesis and reinforce the potential in clinical settings. The tau-depleted human iPSC models can now be applied at scale to investigate the involvement of tau in disease-relevant pathways and cell types.

neuroscience↗