Embryonic Development, Neural Development, Retinal Anomalies
Conditions
Keywords
retina, visual cortex, cognitive cortex, neurogenesis
Brief summary
This research studies how nerve cells in the human embryonic retina, visual brain regions, and brain areas responsible for higher cognitive functions grow, develop, and form interconnected functional networks. Eye tissue, visual brain tissue, and other brain tissue linked to advanced cognitive functions will be collected from embryos whose pregnancies were terminated due to medical conditions or illnesses. High-throughput single-cell and single-nucleus sequencing will be utilized to map gene activity patterns and developmental growth pathways of retinal nerve cells. Multiple testing tools will be combined to analyze these brain and retinal cells: Patch-seq (single-cell patch-clamp sequencing), high-density microelectrode arrays (MEA), and two-photon calcium imaging. With these tools, systematic measurements will be performed on the electrical activity, physical shape, synaptic connection patterns, and signal coding functions of neurons in the retina and visual brain regions. Multi-modal tissue maps and a public database will be constructed to store all collected research data. Immunofluorescence staining will also be applied to compare structural differences and nerve fiber connections between visual brain regions and higher cognitive brain areas. The regenerative capacity and neuron formation process of embryonic brain stem cells, as well as the migration paths of developing neurons, will be tracked. Overall, this study aims to fully uncover the neural foundation of visual signal processing, and identify the molecular regulatory networks that control nerve tissue development during the embryonic stage.
Interventions
OTHERTissue collection and multi-omics sequencing analysis
This observational study collects discarded human embryonic ocular and brain tissues from patients undergoing clinically indicated termination of pregnancy, with gestational age ranging from 9 to 40 weeks. We separate retinal, visual cortex and high-order cognitive cortex tissues, then perform single-cell multi-omics sequencing including transcriptome, chromatin accessibility and proteome profiling. The data is used to explore retinal neurogenesis, neuronal developmental trajectories and multi-modal cell atlas of embryonic visual system, without any clinical intervention on participants.
Sponsors
Sheng Liu
Third Affiliated Hospital, Sun Yat-Sen University
Study design
Observational model
CASE_CONTROL
Time perspective
RETROSPECTIVE
Eligibility
Sex/Gender
ALL
Healthy volunteers
Yes
Inclusion criteria
* Abnormal group: Embryos with clinically confirmed embryonic developmental abnormalities requiring medical termination of pregnancy; intact retinal, visual and cognitive brain tissues available for snATAC-seq, scRNA-seq, electrophysiology, proteomics and RNAscope detection. Normal group: Embryos confirmed free of any ocular and central nervous developmental defects by prenatal examination and anatomical observation; intact embryonic ocular and brain tissues meeting all experimental detection standards. All sample donors have signed written informed consent authorizing the use of residual embryonic tissues for scientific research, with no monetary compensation involved.
Exclusion criteria
* Embryonic ocular or brain tissues with severe necrosis, structural damage or microbial contamination that cannot support multi-omics and functional experiments. Donors who withdraw or refuse the consent for tissue research use. Samples with irregular collection, transportation or cryopreservation procedures resulting in tissue degradation and failure to meet experimental requirements.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Single-cell transcriptomic atlas and developmental trajectory of embryonic retinal and visual cortical neurons | Day 1 of tissue collection | Perform single-cell RNA sequencing on human embryonic eye and brain tissues from abnormal developmental group and normal control group. Identify all cell subtypes in retina and visual-associated cognitive cortex, reconstruct continuous developmental trajectory of retinal neurogenesis and visual cortical neurons, and compare neuronal subtype distribution differences between the two groups. |
| Genome-wide chromatin open regions in embryonic visual tissues | Day 1 of tissue collection | Genome-wide chromatin open regions are detected via snATAC-seq on embryonic ocular and brain tissues from case and control groups. |
| Differential chromatin accessibility between normal and malformed embryonic visual tissues | Day 1 of tissue collection | Differential chromatin accessibility signals are identified via integrated analysis of snATAC-seq and scRNA-seq data from embryonic ocular and brain tissues. |
| Candidate pathogenic genes underlying embryonic visual developmental abnormalities | Day 1 of tissue collection | Genes linked to abnormal embryonic visual development are screened based on differential chromatin and transcriptomic profiles. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Action potential firing patterns of embryonic visual neurons | Day 1 of tissue collection | Action potential firing patterns are recorded via combined Patch-seq and MEA on primary cultured retinal and visual cortical neurons from case and control embryonic tissues. |
| Synchronous electrical activity of embryonic neuronal networks | Day 1 of tissue collection | Neuronal network synchronous electrical activity is recorded via combined Patch-seq and MEA on primary cultured retinal and visual cortical neurons from case and control embryonic tissues. |
| Spatial expression localization of key visual development genes detected by RNAscope | The day 1 of embryonic tissue collection after clinical termination of pregnancy | RNAscope in situ hybridization is conducted on embryonic retinal and brain tissue slices to visualize the spatial distribution and quantitative expression levels of candidate pathogenic genes screened from multi-omics data. Compare the spatial gene expression differences between normal embryonic visual tissues and tissues with ocular developmental defects. |
| Differentially expressed proteins identified via global proteome sequencing | Day 1 of tissue collection | Global proteome sequencing is performed on embryonic ocular and brain tissues to generate lists of differentially expressed proteins linked to retinal neurogenesis and visual cortical development. |
| Spatial localization and expression abundance of proteins via immunohistochemistry | Day 1 of tissue collection | Immunohistochemistry staining is applied on embryonic tissue sections to detect spatial localization and expression abundance of core differentially expressed proteins. |
Countries
China
Contacts
CONTACTSheng Liu, Doctor
CONTACTJing Su
Outcome results
None listed