What question did this study set out to answer?

This research aims to understand how ODAD1 variants affect ciliary function and cytoskeletal integrity in primary ciliary dyskinesia.

April 1, 2026Open Access

Loss-of-function variants in ODAD1 disrupt ODA docking and induce actin cytoskeletal remodeling in primary ciliary dyskinesia

CHChunxiao HuoChildren's Hospital of Zhejiang University TLTing LuoXuzhou Medical College SYShuo YangSir Run Run Shaw Hospital

Key Points

This research aims to understand how ODAD1 variants affect ciliary function and cytoskeletal integrity in primary ciliary dyskinesia.
Identification of homozygous loss-of-function variants in ODAD1 in patients.
Assessment of ciliary beating frequency in patient-derived epithelial cells.
Ultrastructural analysis using electron microscopy techniques.
Evaluation of actin cytoskeletal changes through proteomic profiling.
Testing pharmacological interventions to rescue multiciliated cell abundance.
Novel loss-of-function and recurrent splicing variants in ODAD1 were identified in seven patients.
Significant reductions in ciliary beating frequency and motility defects were observed in patient-derived cells.
Destruction of outer dynein arms and docking complexes was confirmed via electron microscopy.
Actin cytoskeletal rearrangements included abnormal F-actin bundling and reduced multiciliated cells.
Rescue experiments with cytochalasin B and lentiviral re-expression of ODAD1 restored ciliary functionality.

Abstract

Abstract Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder characterized by defective mucociliary clearance due to impaired motile cilia function. Outer dynein arm docking complex subunit 1 (ODAD1) encodes a structural component of the outer dynein arm docking complex (ODA-DC), which is crucial for effective ciliary beating. However, the full spectrum of ODAD1 -associated pathogenesis remains incompletely defined. Here, we identified one novel homozygous loss-of-function ODAD1 variant, c. 705₇06insGCAG, and a recurrent homozygous splicing variant, c. -41-2A > C, in seven unrelated patients. These patients exhibited hallmark PCD symptoms with reduced nasal nitric oxide levels and situs inversus. Patient-derived nasal epithelial cells and air‒liquid interface (ALI) cultures exhibited a markedly reduced ciliary beating frequency and severe motility defects. Transmission electron microscopy and cryo-electron microscopy showed a complete loss of outer dynein arms and docking complexes, with variant-specific ultrastructural abnormalities. Unexpectedly, ODAD1 deficiency also led to reduced multiciliated cells (MCCs) abundance, misoriented basal bodies, and impaired multiciliogenesis. Proteomic profiling and immunostaining revealed prominent actin cytoskeletal remodeling, including aberrant F-actin bundling throughout the epithelial layers. Pharmacological inhibition of actin polymerization using cytochalasin B partially rescued the abundance of MCCs and multiciliogenesis, indicating that actin dysregulation is a modifiable consequence of ODAD1 loss. Finally, lentiviral re-expression of wild-type ODAD1 in patient-derived organoids restored ODA assembly and rescued coordinated ciliary beating, confirming the pathogenicity of the identified variants. Our data reveal a dual role for ODAD1 in regulating both axonemal structure and epithelial cytoskeletal integrity and identify actin dysregulation as a previously unrecognized, targetable pathological mechanism of ODAD1 -associated PCD.

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