Mislocalization of DNAH5 and DNAH9 in respiratory cells from patients with primary ciliary dyskinesia.
BACKGROUND
Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder characterized by recurrent infections of the airways and situs inversus in half of the affected offspring. The most frequent genetic defects comprise recessive mutations of DNAH5 and DNAI1, which encode outer dynein arm (ODA) components. Diagnosis of PCD usually relies on electron microscopy, which is technically demanding and sometimes difficult to interpret.


METHODS
Using specific antibodies, we determined the subcellular localization of the ODA heavy chains DNAH5 and DNAH9 in human respiratory epithelial and sperm cells of patients with PCD and control subjects by high-resolution immunofluorescence imaging. We also assessed cilia and sperm tail function by high-speed video microscopy.


RESULTS
In normal ciliated airway epithelium, DNAH5 and DNAH9 show a specific regional distribution along the ciliary axoneme, indicating the existence of at least two distinct ODA types. DNAH5 was completely or only distally absent from the respiratory ciliary axoneme in patients with PCD with DNAH5- (n = 3) or DNAI1- (n = 1) mutations, respectively, and instead accumulated at the microtubule-organizing centers. In contrast to respiratory cilia, sperm tails from a patient with DNAH5 mutations had normal ODA heavy chain distribution, suggesting different modes of ODA generation in these cell types. Blinded investigation of a large cohort of patients with PCD and control subjects identified DNAH5 mislocalization in all patients diagnosed with ODA defects by electron microscopy (n = 16). Cilia with complete axonemal DNAH5 deficiency were immotile, whereas cilia with distal DNAH5 deficiency showed residual motility.


CONCLUSIONS
Immunofluorescence staining can detect ODA defects, which will possibly aid PCD diagnosis.
Fliegauf
Manfred
M
Department of Pediatrics and Adolescent Medicine, Mathildenstrasse 1, 79106 Freiburg, Germany.
Olbrich
Heike
H
Horvath
Judit
J
Wildhaber
Johannes H
JH
Zariwala
Maimoona A
MA
Kennedy
Marcus
M
Knowles
Michael R
MR
Omran
Heymut
H
D056444:Axonemal Dyneins; D002478:Cells, Cultured; D002923:Cilia / Q000473:pathology / Q000648:ultrastructure; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D004398:Dyneins / Q000235:genetics*; D005260:Female; D005455:Fluorescent Antibody Technique; D018740:Genetic Heterogeneity; D020022:Genetic Predisposition to Disease; D006801:Humans; D015151:Immunoblotting; D007619:Kartagener Syndrome / Q000175:diagnosis* / Q000235:genetics*; D008297:Male; D010375:Pedigree; D012680:Sensitivity and Specificity
D056444:Axonemal Dyneins; C497507:DNAH5 protein, human; C430745:DNAH9 protein, human; D004398:Dyneins