Primary ciliary dyskinesia (PCD) is a congenital, motile ciliopathy with pleiotropic symptoms. Although nearly 50 causative genes have been identified, they only account for approximately 70% of definitive PCD cases. Dynein axonemal heavy chain 10 (DNAH10) encodes a subunit of the inner arm dynein heavy chain in motile cilia and sperm flagella. Based on the common axoneme structure of motile cilia and sperm flagella, DNAH10 variants are likely to cause PCD. Using exome sequencing, we identified a novel DNAH10 homozygous variant (c.589C > T, p.R197W) in a patient with PCD from a consanguineous family. The patient manifested sinusitis, bronchiectasis, situs inversus, and asthenoteratozoospermia. Immunostaining analysis showed the absence of DNAH10 and DNALI1 in the respiratory cilia, and transmission electron microscopy revealed strikingly disordered axoneme 9+2 architecture and inner dynein arm defects in the respiratory cilia and sperm flagella. Subsequently, animal models of Dnah10-knockin mice harboring missense variants and Dnah10-knockout mice recapitulated the phenotypes of PCD, including chronic respiratory infection, male infertility, and hydrocephalus. To the best of our knowledge, this study is the first to report DNAH10 deficiency related to PCD in human and mouse models, which suggests that DNAH10 recessive mutation is causative of PCD.
Humans ; Male ; Animals ; Mice ; Semen/metabolism* ; Dyneins/metabolism* ; Cilia/metabolism* ; Mutation ; Ciliary Motility Disorders/genetics*

Primary ciliary dyskinesia (PCD) is a highly heterogeneous recessive inherited disorder. FAP54, the homolog of CFAP54 in Chlamydomonas reinhardtii, was previously demonstrated as the C1d projection of the central microtubule apparatus of flagella. A Cfap54 knockout mouse model was then reported to have PCD-relevant phenotypes. Through whole-exome sequencing, compound heterozygous variants c.2649_2657delinC (p. E883Dfs*47) and c.7312_7313insCGCAGGCTGAATTCTTGG (p. T2438delinsTQAEFLA) in a new suspected PCD-relevant gene, CFAP54, were identified in an individual with PCD. Two missense variants, c.4112A>C (p. E1371A) and c.6559C>T (p. P2187S), in CFAP54 were detected in another unrelated patient. In this study, a minigene assay was conducted on the frameshift mutation showing a reduction in mRNA expression. In addition, a CFAP54 in-frame variant knock-in mouse model was established, which recapitulated the typical symptoms of PCD, including hydrocephalus, infertility, and mucus accumulation in nasal sinuses. Correspondingly, two missense variants were deleterious, with a dramatic reduction in mRNA abundance from bronchial tissue and sperm. The identification of PCD-causing variants of CFAP54 in two unrelated patients with PCD for the first time provides strong supportive evidence that CFAP54 is a new PCD-causing gene. This study further helps expand the disease-associated gene spectrum and improve genetic testing for PCD diagnosis in the future.
Mice ; Animals ; Humans ; Male ; Kartagener Syndrome/metabolism* ; Cilia/metabolism* ; Semen ; Genetic Testing ; RNA, Messenger ; Mutation

In growing children, growth plate cartilage has limited self-repair ability upon fracture injury always leading to limb growth arrest. Interestingly, one type of fracture injuries within the growth plate achieve amazing self-healing, however, the mechanism is unclear. Using this type of fracture mouse model, we discovered the activation of Hedgehog (Hh) signaling in the injured growth plate, which could activate chondrocytes in growth plate and promote cartilage repair. Primary cilia are the central transduction mediator of Hh signaling. Notably, ciliary Hh-Smo-Gli signaling pathways were enriched in the growth plate during development. Moreover, chondrocytes in resting and proliferating zone were dynamically ciliated during growth plate repair. Furthermore, conditional deletion of the ciliary core gene Ift140 in cartilage disrupted cilia-mediated Hh signaling in growth plate. More importantly, activating ciliary Hh signaling by Smoothened agonist (SAG) significantly accelerated growth plate repair after injury. In sum, primary cilia mediate Hh signaling induced the activation of stem/progenitor chondrocytes and growth plate repair after fracture injury.
Mice ; Animals ; Hedgehog Proteins/genetics* ; Receptors, G-Protein-Coupled/metabolism* ; Cilia/metabolism* ; Cartilage/metabolism* ; Regeneration

Primary ciliary dyskinesia (PCD) is a hereditary disease characterized by airway mucociliary clearance dysfunction. The estimated prevalence of PCD is 1꞉10 000 to 1꞉20 000. The main respiratory manifestations in children are cough, expectoration, chronic rhinitis, sinusitis, and chronic otitis media, while the most common symptoms in adults are chronic sinusitis, bronchiectasis, and infertility. About 50% of patients with certain PCD-related gene variants are combined with situs inversus, and the incidence of congenital heart disease is also high. The pathogenesis behind PCD is that gene variants cause structural or functional disorders of respiratory cilia and motile cilia of other organs, leading to a series of heterogeneous clinical manifestations, which makes it difficult to identify and diagnose PCD. Combining different disease screening tools and understanding the relationship between genotypes and phenotypes may facilitate early diagnosis and treatment for PCD.
Chronic Disease ; Cilia/pathology* ; Humans ; Kartagener Syndrome/genetics* ; Phenotype ; Sinusitis

Primary ciliary dyskinesia (PCD) is a recessive genetic disorder of motile cilia with substantial genetic and phenotypic heterogeneity. Clinical features of PCD vary from one patient to another, and no single test has the sensitivity and specificity to accurately diagnose PCD. Genetic testing combined with other auxiliary tests can facilitate the confirmatory diagnosis of PCD. So far more than 40 genes have been associated with PCD, but most research have focused on common genes, which hinders our understanding of other rare PCD-genes. This review has summarized the PCD-associated genes and the corresponding characteristics of dysfunctional cilia, with an aim to provide a basis for early identification of such diseases.
Cilia/genetics* ; Genetic Testing ; Humans ; Kartagener Syndrome/genetics* ; Sensitivity and Specificity

Cilium, an organelle with a unique proteome and organization, protruding from the cell surface, generally serves as a force generator and signaling compartment. During ciliogenesis, ciliary proteins are synthesized in cytoplasm and transported into cilia by intraflagellar transport (IFT) particles, where the inner counterparts undergo reverse trafficking. The homeostasis of IFT plays a key role in cilial structure assembly and signaling transduction. Much progress has been made on the mechanisms and functions of IFT; however, recent studies have revealed the involvement of IFT particle subunits in organogenesis and spermatogenesis. In this review, we discuss new concepts concerning the molecular functions of IFT protein IFT25 and how its interactions with other IFT particle subunits are involved in mammalian development and fertility.
Animals ; Biological Transport ; Carrier Proteins/metabolism* ; Cilia/metabolism* ; Flagella/metabolism* ; Male ; Mammals/metabolism* ; Organogenesis ; Proteins/metabolism* ; Signal Transduction

Abetalipoproteinemia ; Cilia ; Humans ; Kartagener Syndrome

The primary cilium, a sensory organelle that protrudes from the surface of most eukaryotic cells, receives and transduces various critical signals that are essential for normal development and homeostasis. Structural or functional disruption of primary cilia causes a number of human diseases, including cancer. Primary cilia has cross talks with cell cycle and it may act as a cell cycle checkpoint to suppress cancer development. Moreover, primary cilia has cross-regulation with autophagy, which may affect tumor progression. We then discuss the association of the primary cilia with several oncogenic signaling pathways, including Shh, Wnt, Notch and platelet-derived growth factor receptor (PDGFR). Since these signaling pathways are often over-activated in many types of human cancers, primary cilia are likely to play a role in the tumorigenesis by modulating these pathways. Finally, we summarize current progress on the role of cilia during tumorigenesis and the challenges that the cilia-cancer field faces.
Autophagy ; Carcinogenesis ; Cilia ; Homeostasis ; Humans ; Signal Transduction

Cilia ; Humans

Cellular primary cilium, located on the surface of virtually all mammalian cells, is a strictly conserved organelle which regulates cell biological process and maintains cell homeostasis by modulating cell proliferation, differentiation, migration, polarity, signal cascades and other life activities. Some diseases caused by mutations in genes encoding structural proteins or accessory proteins of primary cilia are collectively termed as "ciliopathies", which can occur in embryo, infancy and even adulthood. Ciliopathies not only involve a single organ, but also involve multiple organs and multiple systems, showing variable symptoms and overlapping symptoms. This review mainly summarizes the effects of ciliopathy-associated gene mutations on bone, tooth, skin, liver and bile duct, kidney, brain, retina, heart and other organs, uncovers their molecular mechanisms and provides some novel insights into therapy of ciliopathies.
Adult ; Animals ; Cilia ; Ciliopathies/genetics* ; Humans ; Proteins ; Retina ; Signal Transduction