Neuronal excitatory-to-inhibitory balance is altered in cerebral organoid models of genetic neurological diseases

Abstract

The neuro-physiological properties of individuals with genetic pre-disposition to neurological disorders are largely unknown. Here we aimed to explore these properties using cerebral organoids (COs) derived from fibroblasts of individuals with confirmed genetic mutations including PRNPE200K, trisomy 21 (T21), and LRRK2G2019S, which are associated with Creutzfeldt Jakob disease, Down Syndrome, and Parkinson’s disease. We utilized no known disease/healthy COs (HC) as normal function controls. At 3–4 and 6–10 months post-differentiation, COs with mutations showed no evidence of disease-related pathology. Electrophysiology assessment showed that all COs exhibited mature neuronal firing at 6–10 months old. At this age, we observed significant changes in the electrophysiology of the COs with disease-associated mutations (dCOs) as compared with the HC, including reduced neuronal network communication, slowing neuronal oscillations, and increased coupling of delta and theta phases to the amplitudes of gamma oscillations. Such changes were linked with the detection of hypersynchronous events like spike-and-wave discharges. These dysfunctions were associated with altered production and release of neurotransmitters, compromised activity of excitatory ionotropic receptors including receptors of kainate, AMPA, and NMDA, and changed levels and function of excitatory glutamatergic synapses and inhibitory GABAergic synapses. Neuronal properties that modulate GABAergic inhibition including the activity of Na–K-Cl cotransport 1 (NKCC1) in Cl− homeostasis and the levels of synaptic and extra-synaptic localization of GABA receptors (GABARs) were altered in the T21 COs only. The neurosteroid allopregnanolone, a positive modulator of GABARs, was downregulated in all the dCOs. Treatment with this neurosteroid significantly improved the neuronal communication in the dCOs, possibly through improving the GABAergic inhibition. Overall, without the manifestation of any disease-related pathology, the genetic mutations PRNPE200K, T21, and LRRK2G2019S significantly altered the neuronal network communication in dCOs by disrupting the excitatory-to-inhibitory balance.

Human cerebral spheroids undergo 4-aminopyridine-induced, activity associated changes in cellular composition and microrna expression

“…Although this approach allowed us to satisfactorily record from the intact organoid, rather than outgrowth cells present in longer-maintained cultures, fewer active electrodes were engaged, which may have contributed to the low efficiency and higher variability observed in our recordings. Future studies in which the adhesion of the spheroids to electrodes is improved through coating with poly-ornithine, laminin or polyethyleneimine or physically enforced with a harp slice grid placed over the spheroids to submerge it completely 19 , 40 , 41 will likely be necessary to resolve this issue.…”

Stress and viral insults do not trigger E200K PrP conversion in human cerebral organoids

“…The human cells used in this study were obtained from a commercial source (Applied Stem Cell) or from skin punch biopsy of an asymptomatic donor carrying a single (heterozygous) glutamic acid to lysine prion protein gene mutation at codon 200 (methionine homozygous at codon 129). These cells and procedures have been described previously [ 28 , 29 ]. Briefly, cells were collected at Case Western Reserve University following the Institutional Review Board (IRB) protocol IRB No.…”

Synaptic Disruption by Soluble Oligomers in Patients with Alzheimer’s and Parkinson’s Disease

“…While it is still not clear how aSynOs relate to the loss of SNpc, it is clear that a complex series of pathways interact to produce early dysfunction of SNpc [ 166 ]. Recent studies in human organoids with mutations linked to PD show that the E/I is altered in PD with lower inhibition and reduced levels of neurosteroid allopregrananolone even before the presence of neuropathology is observed [ 167 ]. This indicates that E/I alterations precede pathology, and its correction may have disease-modifying effects.…”