Periodic Reporting for period 1 - MapGen (Determining Genetic Bases of Differential Response to Antipsychotics Using Patient-Derived Neurons)
Période du rapport: 2023-01-01 au 2024-12-31
Schizophrenia (SCZ) remains a major public health concern, partly due to the variable efficacy of current antipsychotic treatments. Not all individuals experience relief from standard medications, resulting in prolonged illness and considerable social and economic burdens. Motivated by these challenges, our project seeks to uncover the genetic factors and cellular mechanisms that drive this differential treatment response. By focusing on rare genetic variants linked to non-responsiveness, we aim to devise precision medicine approaches that could revolutionize therapeutic strategies for SCZ.
1. Establishment of Human Cortical Organoids: We successfully generated 3D human cortical organoids from induced pluripotent stem cells (iPSCs), creating a physiologically relevant model for studying the cellular basis of schizophrenia (SCZ).
2. Implementation of a Pooled CRISPR Screening Approach: Guided by large-scale genomic studies, we introduced rare de novo variants into our organoid model, targeting genes strongly associated with treatment-resistant SCZ. A pooled CRISPR library was designed to systematically knock out these candidate genes, providing a comprehensive view of their effects on neuronal maturation and function.
3. Optimization of Antipsychotic Treatment Conditions: Using multi-electrode array (MEA) recordings, we determined the optimal concentrations of clozapine and its active metabolite (N-Desmethylclozapine) that induce measurable electrophysiological changes in the glutamatergic neurons.
4. Long-Term Culture and Sample Collection for Single-Cell Analysis: Organoids were cultured to 180 days to achieve enhanced cellular maturity, closely approximating mid-fetal human brain development. This workflow sets the stage for single-cell RNA sequencing (scRNAseq) to dissect cell-type-specific transcriptomic changes.
2. Implementation of a Pooled CRISPR Screening Approach: Guided by large-scale genomic studies, we introduced rare de novo variants into our organoid model, targeting genes strongly associated with treatment-resistant SCZ. A pooled CRISPR library was designed to systematically knock out these candidate genes, providing a comprehensive view of their effects on neuronal maturation and function.
3. Optimization of Antipsychotic Treatment Conditions: Using multi-electrode array (MEA) recordings, we determined the optimal concentrations of clozapine and its active metabolite (N-Desmethylclozapine) that induce measurable electrophysiological changes in the glutamatergic neurons.
4. Long-Term Culture and Sample Collection for Single-Cell Analysis: Organoids were cultured to 180 days to achieve enhanced cellular maturity, closely approximating mid-fetal human brain development. This workflow sets the stage for single-cell RNA sequencing (scRNAseq) to dissect cell-type-specific transcriptomic changes.
Refined Disease Model and Expanded Knowledge Base: By integrating a pooled CRISPR screening approach into long-term human cortical organoid cultures, we have established a high-fidelity disease model that captures the cellular diversity and complexity of the developing human brain. Preliminary analyzes indicate that treatment of glutamatergic neurons with clozapine results in measurable alterations in neuronal firing patterns, shedding light on the molecular and electrophysiological underpinnings of treatment resistance.
Advancement Toward Personalized Therapies: The identification of gene-specific effects on drug responsiveness enables the development of more targeted antipsychotic therapies. This work has the potential to reduce the trial-and-error process currently experienced by patients and clinicians, fostering improved patient outcomes and cost savings in healthcare systems.
Further Direction: Continued functional assays—including single-cell transcriptomics—will be essential for pinpointing the exact mechanisms of action for each genetic variant.
Advancement Toward Personalized Therapies: The identification of gene-specific effects on drug responsiveness enables the development of more targeted antipsychotic therapies. This work has the potential to reduce the trial-and-error process currently experienced by patients and clinicians, fostering improved patient outcomes and cost savings in healthcare systems.
Further Direction: Continued functional assays—including single-cell transcriptomics—will be essential for pinpointing the exact mechanisms of action for each genetic variant.