Related Experiment Video
Updated: Sep 12, 2025
Reconstruct Human Retinoblastoma In Vitro
Published on: October 11, 2022
Identification and characterization of early human photoreceptor states and cell-state-specific
Dominic W H Shayler1,2, Kevin Stachelek1,3, Linda Cambier1
1The Vision Center, Department of Surgery, and Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, United States.
Abstract:
Human cone photoreceptors differ from rods and serve as the retinoblastoma cell-of-origin, yet the developmental basis for their distinct behaviors is poorly understood. Here, we used deep full-length single-cell RNA-sequencing (scRNA-seq) to distinguish post-mitotic cone and rod developmental states and identify cone-specific features related to retinoblastomagenesis. The analyses revealed nascent, immediately post-mitotic cone and rod precursors characterized by higher THRB or NRL regulon activities, immature and maturing cone and rod precursors with concurrent cone- and rod-related gene and regulon expression, and distinct early and late cone and rod maturation states distinguished by maturation-associated declines in RAX regulon activity. Cell-state-specific gene expression features inferred from full-length scRNA-seq were consistent with past 3' scRNA-seq analyses. Beyond the cell state characterizations, full-length scRNA-seq revealed that both L/M cone and rod precursors co-expressed NRL and THRB RNAs yet differentially expressed functionally antagonistic NRL isoforms and prematurely terminated THRB transcripts. Moreover, early L/M cone precursors sequentially expressed several lncRNAs along with MYCN, which composed the seventh most L/M-cone-specific regulon, and SYK, which was implicated in the cone precursors' proliferative response to RB1 loss. These findings reveal previously unresolved photoreceptor precursor states and suggest a role for early cone-precursor-intrinsic SYK expression in retinoblastoma initiation.
Insights
Human cone photoreceptors, the origin of retinoblastoma, have poorly understood developmental paths. This study used single-cell RNA sequencing to identify distinct cone and rod precursor states and found early cone precursors may drive retinoblastoma via SYK expression.
Area of Science:
- Retinal development
- Photoreceptor biology
- Cancer genomics
Background:
- Human cone photoreceptors, the cell-of-origin for retinoblastoma, exhibit distinct developmental trajectories compared to rods, which remain poorly understood.
- Understanding these early developmental differences is crucial for elucidating retinoblastoma pathogenesis.
Purpose of the Study:
- To delineate distinct developmental states of post-mitotic cone and rod photoreceptor precursors using deep full-length single-cell RNA sequencing (scRNA-seq).
- To identify cone-specific molecular features associated with retinoblastoma initiation.
Main Methods:
- Deep full-length single-cell RNA sequencing (scRNA-seq) was employed to analyze photoreceptor precursor development.
- Differential gene and regulon expression analysis was performed to distinguish cell states and identify cone-specific features.
Main Results:
- Distinct developmental states were identified, including nascent, immature, maturing, and late maturation stages for both cone and rod precursors.
- Cone and rod precursors co-expressed key genes like NRL and THRB but showed differential expression of isoforms and transcript termination.
- Early L/M cone precursors exhibited sequential expression of lncRNAs, MYCN, and SYK, with SYK implicated in the proliferative response to RB1 loss.
Conclusions:
- This study resolves previously uncharacterized photoreceptor precursor states, providing a detailed map of early cone and rod development.
- Early cone precursor-intrinsic SYK expression is suggested as a potential driver in retinoblastoma initiation.
