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Updated: Aug 29, 2025
2D and 3D Human Induced Pluripotent Stem Cell-Based Models to Dissect Primary Cilium Involvement during Neocortical Development
Published on: March 25, 2022
In vitro modeling and rescue of ciliopathy associated with IQCB1/NPHP5 mutations using patient-derived cells
Kamil Kruczek1, Zepeng Qu1, Emily Welby1
1Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
Abstract:
Mutations in the IQ calmodulin-binding motif containing B1 (IQCB1)/NPHP5 gene encoding the ciliary protein nephrocystin 5 cause early-onset blinding disease Leber congenital amaurosis (LCA), together with kidney dysfunction in Senior-Løken syndrome. For in vitro disease modeling, we obtained dermal fibroblasts from patients with NPHP5-LCA that were reprogrammed into induced pluripotent stem cells (iPSCs) and differentiated into retinal pigment epithelium (RPE) and retinal organoids. Patient fibroblasts and RPE demonstrated aberrantly elongated ciliary axonemes. Organoids revealed impaired development of outer segment structures, which are modified primary cilia, and mislocalization of visual pigments to photoreceptor cell soma. All patient-derived cells showed reduced levels of CEP290 protein, a critical cilia transition zone component interacting with NPHP5, providing a plausible mechanism for aberrant ciliary gating and cargo transport. Disease phenotype in NPHP5-LCA retinal organoids could be rescued by adeno-associated virus (AAV)-mediated IQCB1/NPHP5 gene augmentation therapy. Our studies thus establish a human disease model and a path for treatment of NPHP5-LCA.
Insights
Mutations in the IQCB1/NPHP5 gene cause Leber congenital amaurosis (LCA). Patient-derived cells and retinal organoids showed ciliary defects, but gene therapy via adeno-associated virus (AAV) rescued the disease phenotype.
Area of Science:
- Genetics and Molecular Biology
- Ophthalmology
- Cell Biology
Background:
- Leber congenital amaurosis (LCA) is an early-onset blinding disease.
- Mutations in the IQ calmodulin-binding motif containing B1 (IQCB1)/NPHP5 gene cause LCA and kidney dysfunction in Senior-Løken syndrome.
- NPHP5 is a ciliary protein crucial for photoreceptor function.
Purpose of the Study:
- To establish an in vitro disease model for NPHP5-LCA.
- To investigate the cellular and molecular mechanisms underlying NPHP5-LCA.
- To explore potential therapeutic strategies for NPHP5-LCA.
Main Methods:
- Reprogramming patient fibroblasts into induced pluripotent stem cells (iPSCs).
- Differentiating iPSCs into retinal pigment epithelium (RPE) and retinal organoids.
- Analyzing ciliary structure, protein levels (CEP290), and visual pigment localization.
Main Results:
- Patient-derived fibroblasts and RPE exhibited elongated ciliary axonemes.
- Retinal organoids showed impaired outer segment development and mislocalized visual pigments.
- Reduced CEP290 protein levels were observed, suggesting impaired ciliary gating and transport.
- Adeno-associated virus (AAV)-mediated IQCB1/NPHP5 gene augmentation rescued the disease phenotype in organoids.
Conclusions:
- Established a human NPHP5-LCA disease model using patient-derived iPSCs and organoids.
- Identified aberrant ciliary gating and cargo transport due to reduced CEP290 as a potential mechanism.
- Demonstrated the therapeutic potential of AAV-mediated gene augmentation for NPHP5-LCA.
