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Updated: May 5, 2026
Generation of iPSC-derived Human Brain Organoids to Model Early Neurodevelopmental Disorders
Published on: April 14, 2017
Excitatory Cortical Neurons from CDKL5 Deficiency Disorder Patient-Derived Organoids Show Early Hyperexcitability Not
Abstract:
CDKL5 deficiency disorder (CDD) is a rare developmental and epileptic encephalopathy resulting from variants in cyclin-dependent kinase-like 5 (CDKL5) that lead to impaired kinase activity or loss of function. CDD is one of the most common genetic etiologies identified in epilepsy cohorts. To study how CDKL5 variants impact human neuronal activity, gene expression and morphology, CDD patient-derived induced pluripotent stem cells and their isogenic controls were differentiated into excitatory neurons using either an NGN2 induction protocol or a guided cortical organoid differentiation. Patient-derived neurons from both differentiation paradigms had decreased phosphorylated EB2, a known molecular target of CDKL5. Induced neurons showed no detectable differences between cases and isogenic controls in network activity using a multielectrode array, or in MAP2+ neurite length, and only two genes were differentially expressed. However, patient-derived neurons from the organoid differentiation showed increased synchrony and weighted mean firing rate on the multielectrode array within the first month of network maturation. CDD patient-derived cortical neurons had lower expression of CDKL5 and HS3ST1, which may change the extracellular matrix around the synapse and contribute to hyperexcitability. Similar to the induced neurons, there were no differences in neurite length across or within patient-control cell lines. Induced neurons have poor cortical specification while the organoid derived neurons expressed cortical markers, suggesting that the changes in neuronal excitability and gene expression are specific to cortical excitatory neurons. Examining molecular mechanisms of early hyperexcitability in cortical neurons is a promising avenue for identification of CDD therapeutics.
Insights
CDKL5 deficiency disorder (CDD) patient neurons show altered network activity and gene expression, particularly in cortical neurons, offering insights into early hyperexcitability and potential therapeutics.
Area of Science:
- Neuroscience
- Genetics
- Developmental Biology
Background:
- CDKL5 deficiency disorder (CDD) is a severe neurodevelopmental disorder linked to CDKL5 gene variants.
- It is a leading genetic cause of epilepsy, impacting neuronal function.
- Understanding CDKL5's role in neuronal development is crucial for therapeutic strategies.
Purpose of the Study:
- To investigate how CDKL5 variants affect human neuronal activity, gene expression, and morphology.
- To compare neuronal differentiation using NGN2 induction versus cortical organoids.
- To identify molecular mechanisms underlying early hyperexcitability in CDD.
Main Methods:
- Differentiated CDD patient-derived induced pluripotent stem cells and isogenic controls into excitatory neurons.
- Utilized NGN2 induction and guided cortical organoid differentiation protocols.
- Assessed neuronal activity via multielectrode array, gene expression, and neurite morphology.
Main Results:
- Patient neurons showed decreased phosphorylated EB2, a CDKL5 target.
- Organoid-derived cortical neurons exhibited increased network synchrony and firing rates.
- Cortical neurons displayed reduced CDKL5 and HS3ST1 expression, potentially affecting synaptic extracellular matrix.
Conclusions:
- Cortical neuron specificity is key for observing CDD-related neuronal excitability and gene expression changes.
- Early hyperexcitability mechanisms in cortical neurons are a promising target for CDD therapeutics.
- Organoid models better recapitulate CDD pathophysiology compared to simple induced neurons.
