Altered energy metabolism in Fatal Familial Insomnia cerebral organoids is associated with astrogliosis and neuronal dysfunction

Abstract

Fatal familial insomnia (FFI) is a rare neurodegenerative disease caused by a dominantly inherited single amino acid substitution (D178N) within the prion protein (PrP). No in vitro human brain tissue model for this disease has previously been available. Consequently, how this mutation exerts its damaging effect on brain cells is still unknown. Using CRISPR-Cas9 engineered induced pluripotent stem cells, we made D178N cerebral organoids and compared these with isotype control organoids. We found that, in the absence of other hallmarks of FFI, the D178N organoids exhibited astrogliosis with cellular oxidative stress. Abnormal post-translational processing of PrP was evident but no tissue deposition or propagation of mis-folded PrP isoforms were observed. Neuronal electrophysiological function was compromised and levels of neurotransmitters, particularly acetylcholine and GABA, altered. Underlying these dysfunctions were changes in cellular energy homeostasis, with substantially increased glycolytic and Krebs cycle intermediates, and greater mitochondrial activity. This increased energy demand in D178N organoids was associated with increased mitophagy and depletion of lipid droplets, in turn resulting in shifts of cellular lipid composition. Using a double mutation (178NN) we could confirm that most changes were caused by the presence of the mutation rather than interaction with PrP molecules lacking the mutation. Our data strongly suggests that shifting biosynthetic intermediates and oxidative stress, caused by an imbalance of energy supply and demand, results in astrogliosis with compromised neuronal activity in FFI organoids. They further support that many of the disease associated changes are due to a corruption of PrP function and do not require propagation of PrP mis-folding.

Neural cell engraftment therapy for sporadic Creutzfeldt-Jakob disease restores neuroelectrophysiological parameters in a cerebral organoid model

“…To determine if NPCs might be able to rescue certain disease parameters, we devised an approach to introduce NPCs after infection of the organoids with sCJD prions at a point where significant prion propagation had already occurred. Human COs were differentiated from iPSCs using the Lancaster and Knoblich protocol [ 28 ] that produces organoids with populations of mature neurons, astrocytes and oligodendrocytes, with depletion of the progenitor populations over time (characterized in [ 24 , 25 , 29 ] and Additional file 1 : Fig. S2).…”

“…The infection could be reduced by treatment with PPS either administered before and during infection or after establishment of infection, supporting the use of the organoid model for screening putative therapeutic strategies [ 23 ]. An advantage to the organoid model is that neuronal function during infection and treatment can be measured using neuroelectrophysiology [ 24 , 25 ]. In this way, it can be determined if a treatment has the potential to improve neuronal function.…”

A PrP EGFR signaling axis controls neural stem cell senescence through modulating cellular energy pathways

“…NSC samples were collected for metabolomics analysis from cell culture via immersion in ice cold methanol followed by scraping. Following sample collection metabolites were extracted as described previously ( 62 ). Aqueous metabolites were analyzed using a combination of a previously established ion pairing method operating exclusively in negative ionization mode and a pentafluorophenylpropyl (F5) column method operating exclusively in positive ionization mode.…”

Mutant Prion Protein Endoggresomes are Hubs for Local Axonal Organelle-Cytoskeletal Remodeling

“…Mitochondrial dysfunction occurs at early and late stages of neurodegeneration, including in prion diseases [59][60][61] . Mitochondrial membrane potential (DYm) is central to neuronal health, and both increased and decreased membrane potential have been associated with impairments to neuronal mitochondrial quality control in familial and infectious prion disorders 61,62 .…”