Examination of upper respiratory tracts of Siirt-coloured mohair goats by scanning electron microscopy before and after plastination.

Present study was conducted to determine the changes in the surface structure of the upper respiratory tract of Siirt-coloured mohair goats by the silicone plastination method. Accordingly, the heads of 10 Siirt-coloured mohair goats procured from slaughterhouses were divided into two halves. Half of each head was plastinated. After macro-comparisons were made, the deformations of silicone plastination on the surface were examined by comparing the scanning electron microscope (SEM) findings of both upper respiratory tract tissue samples collected from plastinates and fresh material. When the data from scanning electron microscopy were analysed, cilia, cobblestone patterns, goblet cells and gland ducts on the epithelial surface were identified in areas on the upper respiratory tract. The SEM images of the plastinated tissues showed that the surface structures were degenerated due to the deformation of the surface epithelium. The plastination technique damaged the structures on the surface epithelium. Since the plastination technique and scanning electron microscopy have been studied together for the first time, we believe this would contribute to the scientific literature.

Association between Uterine Adenomyosis and Infertility: Role of Axonemal Alteration in Apical Endometria.

ABSTRACT: Uterine adenomyosis is an estrogen-dependent chronic inflammatory condition and may cause painful symptoms, abnormal uterine bleeding, and/or subfertility/infertility. It is characterized by the presence of endometrial glands and stroma within the myometrium causing enlargement of the uterus as a result of reactive hyperplastic and/or hypertrophic change of the surrounding myometrium. Similar to endometriosis, adenomyosis has a negative impact on female fertility. Abnormal uterotubal sperm transport, tissue inflammation, and the toxic effect of chemical mediators have been proposed as contributing factors. Inflammation-induced damage of the mucosal cilia in the fallopian tube has been reported. Besides other proposed mechanisms, our most recent study with transmission electron microscopy analysis indicated that microvilli damage and an axonemal alteration in the apical endometria occur in response to endometrial inflammation. This may be involved in the negative fertility outcome in women with adenomyosis. We present a critical analysis of the literature data concerning the mechanistic basis of infertility in women with adenomyosis and its impact on fertility outcome.

IFT cargo and motors associate sequentially with IFT trains to enter cilia of C. elegans.

Intraflagellar transport (IFT) orchestrates entry of proteins into primary cilia. At the ciliary base, assembled IFT trains, driven by kinesin-2 motors, can transport cargo proteins into the cilium, across the crowded transition zone. How trains assemble at the base and how proteins associate with them is far from understood. Here, we use single-molecule imaging in the cilia of C. elegans chemosensory neurons to directly visualize the entry of kinesin-2 motors, kinesin-II and OSM-3, as well as anterograde cargo proteins, IFT dynein and tubulin. Single-particle tracking shows that IFT components associate with trains sequentially, both in time and space. Super-resolution maps of IFT components in wild-type and mutant worms reveal ciliary ultrastructure and show that kinesin-II is essential for axonemal organization. Finally, imaging cilia lacking kinesin-II and/or transition zone function uncovers the interplay of kinesin-II and OSM-3 in driving efficient transport of IFT trains across the transition zone.

Structure-guided discovery of protein and glycan components in native mastigonemes.

Mastigonemes, the hair-like lateral appendages lining cilia or flagella, participate in mechanosensation and cellular motion, but their constituents and structure have remained unclear. Here, we report the cryo-EM structure of native mastigonemes isolated from Chlamydomonas at 3.0 Å resolution. The long stem assembles as a super spiral, with each helical turn comprising four pairs of anti-parallel mastigoneme-like protein 1 (Mst1). A large array of arabinoglycans, which represents a common class of glycosylation in plants and algae, is resolved surrounding the type II poly-hydroxyproline (Hyp) helix in Mst1. The EM map unveils a mastigoneme axial protein (Mstax) that is rich in heavily glycosylated Hyp and contains a PKD2-like transmembrane domain (TMD). Mstax, with nearly 8,000 residues spanning from the intracellular region to the distal end of the mastigoneme, provides the framework for Mst1 assembly. Our study provides insights into the complexity of protein and glycan interactions in native bio-architectures.

Practical guide for the diagnosis and management of primary ciliary dyskinesia.

OBJECTIVE: Primary ciliary dyskinesia (PCD) is a relatively rare genetic disorder that affects approximately 1 in 20,000 people. Approximately 50 genes are currently known to cause PCD. In light of differences in causative genes and the medical system in Japan compared with other countries, a practical guide was needed for the diagnosis and management of Japanese PCD patients. METHODS: An ad hoc academic committee was organized under the Japanese Rhinologic Society to produce a practical guide, with participation by committee members from several academic societies in Japan. The practical guide including diagnostic criteria for PCD was approved by the Japanese Rhinologic Society, Japanese Society of Otolaryngology-Head and Neck Surgery, Japanese Respiratory Society, and Japanese Society of Pediatric Pulmonology. RESULTS: The diagnostic criteria for PCD consist of six clinical features, six laboratory findings, differential diagnosis, and genetic testing. The diagnosis of PCD is categorized as definite, probable, or possible PCD based on a combination of the four items above. Diagnosis of definite PCD requires exclusion of cystic fibrosis and primary immunodeficiency, at least one of the six clinical features, and a positive result for at least one of the following: (1) Class 1 defect on electron microscopy of cilia, (2) pathogenic or likely pathogenic variants in a PCD-related gene, or (3) impairment of ciliary motility that can be repaired by correcting the causative gene variants in iPS cells established from the patient's peripheral blood cells. CONCLUSION: This practical guide provides clinicians with useful information for the diagnosis and management of PCD in Japan.

Primary Cilia as a Tumor Marker in Pituitary Neuroendocrine Tumors.

Pituitary neuroendocrine tumors (PitNETs) account for approximately 15% of all intracranial neoplasms. Although they usually appear to be benign, some tumors display worse behavior, displaying rapid growth, invasion, refractoriness to treatment, and recurrence. Increasing evidence supports the role of primary cilia (PC) in regulating cancer development. Here, we showed that PC are significantly increased in PitNETs and are associated with increased tumor invasion and recurrence. Serial electron micrographs of PITNETs demonstrated different ciliation phenotypes (dot-like versus normal-like cilia) that represented PC at different stages of ciliogenesis. Molecular findings demonstrated that 123 ciliary-associated genes (eg, doublecortin domain containing protein 2, Sintaxin-3, and centriolar coiled-coil protein 110) were dysregulated in PitNETs, representing the upregulation of markers at different stages of intracellular ciliogenesis. Our results demonstrate, for the first time, that ciliogenesis is increased in PitNETs, suggesting that this process might be used as a potential target for therapy in the future.

A Review: Biomechanical Aspects of the Fallopian Tube Relevant to its Function in Fertility.

The fallopian tube (FT) plays a crucial role in the reproductive process by providing an ideal biomechanical and biochemical environment for fertilization and early embryo development. Despite its importance, the biomechanical functions of the FT that originate from its morphological aspects, and ultrastructural aspects, as well as the mechanical properties of FT, have not been studied nor used sufficiently, which limits the understanding of fertilization, mechanotrasduction, and mechanobiology during embryo development, as well as the replication of the FT in laboratory settings for infertility treatments. This paper reviews and revives valuable information on human FT reported in medical literature in the past five decades relevant to the biomechanical aspects of FT. In this review, we summarized the current state of knowledge concerning the morphological, ultrastructural aspects, and mechanical properties of the human FT. We also investigate the potential arising from a thorough consideration of the biomechanical functions and exploring often neglected mechanical aspects. Our investigation encompasses both macroscopic measurements (such as length, diameter, and thickness) and microscopic measurements (including the height of epithelial cells, the percentage of ciliated cells, cilia structure, and ciliary beat frequency). Our primary focus has been on healthy women of reproductive age. We have examined various measurement techniques, encompassing conventional metrology, 2D histological data as well as new spatial measurement techniques such as micro-CT.

The utility of nasal nitric oxide in the diagnostic evaluation of primary ciliary dyskinesia.

BACKGROUND: There is no gold-standard test for primary ciliary dyskinesia (PCD), rather American Thoracic Society guidelines recommend starting with nasal nitric oxide (nNO) in children ≥5 years old and confirming the diagnosis with genetic testing or ciliary biopsy with transmission electron microscopy (TEM). These guidelines have not been studied in a clinical setting. We present a case series describing the PCD diagnostic process at our pediatric PCD center. METHODS: Diagnostic data from 131 patients undergoing PCD consultation were reviewed. RESULTS: In all participants ≥ 5 years old and who completed nNO using resistor methodology, the first diagnostic test performed was nNO in 77% (73/95), genetic testing in 14% (13/95), and TEM in <1% (9/95). nNO was the only diagnostic test performed in 75% (55/73) of participants who completed nNO first. Seventy-five percent (55/73) had a single above the cutoff nNO value and PCD was determined to be unlikely in 91% (50/55) without performing additional confirmatory testing. Eleven percent (8/73) had multiple below the cutoff nNO values, with 38% (3/8) being diagnosed with PCD by confirmatory testing and 50% (4/8) with negative confirmatory testing, but being managed as PCD. The genetic testing positivity rate was 50% in participants who completed nNO first and 8% when genetic testing was completed first. CONCLUSION: nNO is useful in three situations: an initial above the cutoff nNO value makes PCD unlikely and prevents additional confirmatory testing, repetitively below the cutoff nNO values without positive confirmatory testing suggests a probable PCD diagnosis and the yield of genetic testing is higher when nNO is performed first.

Lianhua Qingke Preserves Mucociliary Clearance in Rat with Acute Exacerbation of Chronic Obstructive Pulmonary Disease by Maintaining Ciliated Cells Proportion and Protecting Structural Integrity and Beat Function of Cilia.

Purpose: Acute Exacerbation of Chronic Obstructive Pulmonary Disease (AECOPD) is a sudden worsening of symptoms in patients with Chronic Obstructive Pulmonary Disease (COPD), such as cough, increased sputum volume, and sputum purulence. COPD and AECOPD are characterized by damage to cilia and increased mucus secretion. Mucociliary clearance (MCC) functions as part of the primary innate system of the lung to remove harmful particles and pathogens together with airway mucus and is therefore crucial for patients with COPD. Methods: AECOPD was induced by cigarette smoke exposure (80 cigarettes/day, 5 days/week for 12 weeks) and lipopolysaccharide (LPS) instillation (200 µg, on days 1, 14, and 84). Rats administered Lianhua Qingke (LHQK) (0.367, 0.732, and 1.465 g/kg/d) or Eucalyptol, Limonene, and Pinene Enteric Soft Capsules (ELP, 0.3 g/kg/d) intragastrically. Pulmonary pathology, Muc5ac+ goblet cell and ß-tubulin IV+ ciliated cells, and mRNA levels of forkhead box J1 (Foxj1) and multiciliate differentiation and DNA synthesis associated cell cycle protein (MCIDAS) were assessed by hematoxylin and eosin staining, immunofluorescence staining, and RT-qPCR, respectively. Ciliary morphology and ultrastructure were examined through scanning electron microscopy and transmission electron microscopy. Ciliary beat frequency (CBF) was recorded using a high-speed camera. Results: Compared to the model group, LHQK treatment groups showed a reduction in inflammatory cell infiltration, significantly reduced goblet cell and increased ciliated cell proportion. LHQK significantly upregulated mRNA levels of MCIDAS and Foxj1, indicating promoted ciliated cell differentiation. LHQK protected ciliary structure and maintained ciliary function via increasing the ciliary length and density, reducing ciliary ultrastructure damage, and ameliorating random ciliary oscillations, consequently enhancing CBF. Conclusion: LHQK enhances the MCC capability of ciliated cells in rat with AECOPD by preserving the structural integrity and beating function of cilia, indicating its therapeutic potential on promoting sputum expulsion in patients with AECOPD.

The genetic framework of primary ciliary dyskinesia assessed by soft computing analysis.

BACKGROUND: International guidelines disagree on how best to diagnose primary ciliary dyskinesia (PCD), not least because many tests rely on pattern recognition. We hypothesized that quantitative distribution of ciliary ultrastructural and motion abnormalities would detect most frequent PCD-causing groups of genes by soft computing analysis. METHODS: Archived data on transmission electron microscopy and high-speed video analysis from 212 PCD patients were re-examined to quantitate distribution of ultrastructural (10 parameters) and functional ciliary features (4 beat pattern and 2 frequency parameters). The correlation between ultrastructural and motion features was evaluated by blinded clustering analysis of the first two principal components, obtained from ultrastructural variables for each patient. Soft computing was applied to ultrastructure to predict ciliary beat frequency (CBF) and motion patterns by a regression model. Another model classified the patients into the five most frequent PCD-causing gene groups, from their ultrastructure, CBF and beat patterns. RESULTS: The patients were subdivided into six clusters with similar values to homologous ultrastructural phenotype, motion patterns, and CBF, except for clusters 1 and 4, attributable to normal ultrastructure. The regression model confirmed the ability to predict functional ciliary features from ultrastructural parameters. The genetic classification model identified most of the different groups of genes, starting from all quantitative parameters. CONCLUSIONS: Applying soft computing methodologies to PCD diagnostic tests optimizes their value by moving from pattern recognition to quantification. The approach may also be useful to evaluate atypical PCD, and novel genetic abnormalities of unclear disease-producing potential in the future.

Ciliary Ultrastructure Assessed by Transmission Electron Microscopy in Adults with Bronchiectasis and Suspected Primary Ciliary Dyskinesia but Inconclusive Genotype.

Whole-exome sequencing has expedited the diagnostic work-up of primary ciliary dyskinesia (PCD), when used in addition to clinical phenotype and nasal nitric oxide. However, it reveals variants of uncertain significance (VUS) in established PCD genes or (likely) pathogenic variants in genes of uncertain significance in approximately 30% of tested individuals. We aimed to assess genotype-phenotype correlations in adults with bronchiectasis, clinical suspicion of PCD, and inconclusive whole-exome sequencing results using transmission electron microscopy (TEM) and ciliary image averaging by the PCD Detect software. We recruited 16 patients with VUS in CCDC39, CCDC40, CCDC103, DNAH5, DNAH5/CCDC40, DNAH8/HYDIN, DNAH11, and DNAI1 as well as variants in the PCD candidate genes DNAH1, DNAH7, NEK10, and NME5. We found normal ciliary ultrastructure in eight patients with VUS in CCDC39, DNAH1, DNAH7, DNAH8/HYDIN, DNAH11, and DNAI1. In six patients with VUS in CCDC40, CCDC103, DNAH5, and DNAI1, we identified a corresponding ultrastructural hallmark defect. In one patient with homozygous variant in NME5, we detected a central complex defect supporting clinical relevance. Using TEM as a targeted approach, we established important genotype-phenotype correlations and definite PCD in a considerable proportion of patients. Overall, the PCD Detect software proved feasible in support of TEM.

Cryo-EM reveals how the mastigoneme assembles and responds to environmental signal changes.

Mastigonemes are thread-like structures adorning the flagella of protists. In Chlamydomonas reinhardtii, filamentous mastigonemes find their roots in the flagella's distal region, associated with the channel protein PKD2, implying their potential contribution to external signal sensing and flagellar motility control. Here, we present the single-particle cryo-electron microscopy structure of the mastigoneme at 3.4 Å. The filament unit, MST1, consists of nine immunoglobulin-like domains and six Sushi domains, trailed by an elastic polyproline-II helix. Our structure demonstrates that MST1 subunits are periodically assembled to form a centrosymmetric, non-polar filament. Intriguingly, numerous clustered disulfide bonds within a ladder-like spiral configuration underscore structural resilience. While defects in the mastigoneme structure did not noticeably affect general attributes of cell swimming, they did impact specific swimming properties, particularly under varied environmental conditions such as redox shifts and heightened viscosity. Our findings illuminate the potential role of mastigonemes in flagellar motility and suggest their involvement in diverse environmental responses.

CiliaMiner: an integrated database for ciliopathy genes and ciliopathies.

Cilia are found in eukaryotic species ranging from single-celled organisms, such as Chlamydomonas reinhardtii, to humans, but not in plants. The ability to respond to repellents and/or attractants, regulate cell proliferation and differentiation and provide cellular mobility are just a few examples of how crucial cilia are to cells and organisms. Over 30 distinct rare disorders generally known as ciliopathy are caused by abnormalities or functional impairments in cilia and cilia-related compartments. Because of the complexity of ciliopathies and the rising number of ciliopathies and ciliopathy genes, a ciliopathy-oriented and up-to-date database is required. Here, we present CiliaMiner, a manually curated ciliopathy database that includes ciliopathy lists collected from articles and databases. Analysis reveals that there are 55 distinct disorders likely related to ciliopathy, with over 4000 clinical manifestations. Based on comparative symptom analysis and subcellular localization data, diseases are classified as primary, secondary or atypical ciliopathies. CiliaMiner provides easy access to all of these diseases and disease genes, as well as clinical features and gene-specific clinical features, as well as subcellular localization of each protein. Additionally, the orthologs of disease genes are also provided for mice, zebrafish, Xenopus, Drosophila, Caenorhabditis elegans and Chlamydomonas reinhardtii. CiliaMiner (https://kaplanlab.shinyapps.io/ciliaminer) aims to serve the cilia community with its comprehensive content and highly enriched interactive heatmaps, and will be continually updated. Database URL: https://kaplanlab.shinyapps.io/ciliaminer/.

Axonemal structures reveal mechanoregulatory and disease mechanisms.

Motile cilia and flagella beat rhythmically on the surface of cells to power the flow of fluid and to enable spermatozoa and unicellular eukaryotes to swim. In humans, defective ciliary motility can lead to male infertility and a congenital disorder called primary ciliary dyskinesia (PCD), in which impaired clearance of mucus by the cilia causes chronic respiratory infections1. Ciliary movement is generated by the axoneme, a molecular machine consisting of microtubules, ATP-powered dynein motors and regulatory complexes2. The size and complexity of the axoneme has so far prevented the development of an atomic model, hindering efforts to understand how it functions. Here we capitalize on recent developments in artificial intelligence-enabled structure prediction and cryo-electron microscopy (cryo-EM) to determine the structure of the 96-nm modular repeats of axonemes from the flagella of the alga Chlamydomonas reinhardtii and human respiratory cilia. Our atomic models provide insights into the conservation and specialization of axonemes, the interconnectivity between dyneins and their regulators, and the mechanisms that maintain axonemal periodicity. Correlated conformational changes in mechanoregulatory complexes with their associated axonemal dynein motors provide a mechanism for the long-hypothesized mechanotransduction pathway to regulate ciliary motility. Structures of respiratory-cilia doublet microtubules from four individuals with PCD reveal how the loss of individual docking factors can selectively eradicate periodically repeating structures.

Ultrafast reversible self-assembly of living tangled matter.

Tangled active filaments are ubiquitous in nature, from chromosomal DNA and cilia carpets to root networks and worm collectives. How activity and elasticity facilitate collective topological transformations in living tangled matter is not well understood. We studied California blackworms (Lumbriculus variegatus), which slowly form tangles in minutes but can untangle in milliseconds. Combining ultrasound imaging, theoretical analysis, and simulations, we developed and validated a mechanistic model that explains how the kinematics of individual active filaments determines their emergent collective topological dynamics. The model reveals that resonantly alternating helical waves enable both tangle formation and ultrafast untangling. By identifying generic dynamical principles of topological self-transformations, our results can provide guidance for designing classes of topologically tunable active materials.

Airway Disease in Children with Primary Ciliary Dyskinesia: Impact of Ciliary Ultrastructure Defect and Genotype.

Rationale: Primary ciliary dyskinesia (PCD) is characterized by impaired mucociliary clearance, recurrent respiratory infections, progressive airway damage, and obstructive lung disease. Although the association of ciliary ultrastructure defect/genotype with the severity of airflow obstruction has been well characterized, their association with airway abnormalities on chest computed tomography (CT) has been minimally evaluated. Objectives: We sought to delineate the association of ciliary defect class/genotype with chest CT scores in children with PCD. Methods: Cross-sectional analysis of children with PCD (N = 146) enrolled in a prospective multicenter observational study, stratified by defect type: outer dynein arm (ODA), ODA/inner dynein arm (IDA), IDA/microtubular disorganization (MTD), and normal/near normal ultrastructure with associated genotypes. CTs were scored using the MERAGMA-PCD (Melbourne-Rotterdam Annotated Grid Morphometric Analysis for PCD), evaluating airway abnormalities in a hierarchical order: atelectasis, bronchiectasis, bronchial wall thickening, and mucus plugging/tree-in-bud opacities. The volume fraction of each component was expressed as the percentage of total lung volume. The percentage of disease was computed as the sum of all components. Regression analyses were used to describe the association between clinical predictors and CT scores. Results: Acceptable chest CTs were obtained in 141 children (71 male): 57 ODA, 20 ODA/IDA, 40 IDA/MTD, and 24 normal/near normal. The mean (standard deviation) age was 8.5 (4.6) years, forced expiratory volume in 1 second (FEV1) percent predicted was 82.4 (19.5), and %Disease was 4.6 (3.5). Children with IDA/MTD defects had a higher %Disease compared with children with ODA defects (2.71% higher [95% confidence interval (CI), 1.37-4.06; P < 0.001]), driven by higher %Mucus plugging (2.35% higher [1.43-3.26; P < 0.001]). Increasing age, lower body mass index, and lower FEV1 were associated with a higher %Disease (0.23%; 95% CI, 0.11-0.35; P < 0.001 and 0.03%; 95% CI, 0.01-0.04; P = 0.008 and 0.05%; 95% CI, 0.01-0.08; P = 0.011, respectively). Conclusions: Children with IDA/MTD defects had significantly greater airway disease on CT, primarily mucus plugging, compared with children with ODA defects.

Laterality Defects in Primary Ciliary Dyskinesia: Relationship to Ultrastructural Defect or Genotype.

Rationale: The association between organ laterality abnormalities and ciliary ultrastructural defect or genotype in primary ciliary dyskinesia is poorly understood. Objectives: To determine if there is an association between presence and/or type of laterality abnormality and ciliary ultrastructural defect or genotype. Methods: Participants with primary ciliary dyskinesia in a multicenter, prospective study were grouped based on ciliary ultrastructural defect or genotype. In a retrospective analysis of these data, the association of ciliary ultrastructural defect or genotype and likelihood of a laterality abnormality was evaluated by logistic regression adjusted for presence of two loss-of-function versus one or more not-loss-of-function variants. Results: Of 559 participants, 286 (51.2%), 215 (38.5%), and 58 (10.4%) were identified as having situs solitus, situs inversustotalis, and situs ambiguus, respectively; heterotaxy, defined as situs ambiguus with complex cardiovascular defects, was present in 14 (2.5%). Compared with the group with inner dynein arm defects with microtubular disorganization, laterality defects were more likely in the outer dynein arm defects group (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.21-3.54; P < 0.01) and less likely in the normal/near normal ultrastructure group (OR, 0.04; 95% CI, 0.013-0.151; P < 0.01). Heterotaxy was present in 11 of 242 (4.5%) in the outer dynein arm defects group but 0 of 96 in the inner dynein arm defects with microtubular disorganization group (P = 0.038). Conclusion: In primary ciliary dyskinesia, risk of a laterality abnormality differs by ciliary ultrastructural defect. Pathophysiologic mechanisms underlying these differences require further exploration.

Evaluation of ciliary functions and ciliary beat frequency via cell culture method in patients with primary ciliary dyskinesia.

BACKGROUND: Cell culture increases both diagnostic specificity and sensitivity of primary ciliary dyskinesia (PCD) and the most important reason to use cell culture for definitive diagnosis in PCD is to exclude secondary ciliary defects. Here we aimed to evaluate the cilia functions and cilia ultrastructural abnormalities after ciliogenesis of cell culture in patients with definitive diagnosis of PCD. We also aimed to compare high speed videomicroscopy (HSVM) results of patients before and after ciliogenesis and to compare them with electron microscopy, genetic and immunofluorescence results in patients with positive diagnosis of PCD. METHODS: This study was conducted as a cross-sectional study in patients with PCD. HSVM, transmission electron microscopy (TEM) and immunofluorescence staining results of the nasal biopsy samples taken from patients with the definitive diagnosis of PCD were evaluated and HSVM findings before and after cell culture were described. RESULTS: Ciliogenesis and regrowth in the cell culture occurred in the nasal biopsy sample of eight patients with PCD. The mean age of the patients was 15.5±4.2 years (8.5-18 years). Mean beat frequency was found to be 7.54±1.01 hz (6.53-9.45 hz) before cell culture, and 7.36±0.86 hz (6.02-7.99 hz) after cell culture in the nasal biopsy of patients. There was no significant difference in the beat frequency of PCD patients before and after cell culture. Ciliary function analysis showed the similar beating pattern before and after cell culture in patients with PCD. CONCLUSIONS: This study showed us that there was no difference between cilia beat frequency and beat pattern before and after cell culture in patients with definitive diagnosis of PCD and repeated HSVM would be a useful diagnostic approach in patients who have no possibility to reach other diagnostic methods.

The evolutionary conserved proteins CEP90, FOPNL, and OFD1 recruit centriolar distal appendage proteins to initiate their assembly.

In metazoa, cilia assembly is a cellular process that starts with centriole to basal body maturation, migration to the cell surface, and docking to the plasma membrane. Basal body docking involves the interaction of both the distal end of the basal body and the transition fibers/distal appendages, with the plasma membrane. Mutations in numerous genes involved in basal body docking and transition zone assembly are associated with the most severe ciliopathies, highlighting the importance of these events in cilium biogenesis. In this context, the ciliate Paramecium has been widely used as a model system to study basal body and cilia assembly. However, despite the evolutionary conservation of cilia assembly events across phyla, whether the same molecular players are functionally conserved, is not fully known. Here, we demonstrated that CEP90, FOPNL, and OFD1 are evolutionary conserved proteins crucial for ciliogenesis. Using ultrastructure expansion microscopy, we unveiled that these proteins localize at the distal end of both centrioles/basal bodies in Paramecium and mammalian cells. Moreover, we found that these proteins are recruited early during centriole duplication on the external surface of the procentriole. Functional analysis performed both in Paramecium and mammalian cells demonstrate the requirement of these proteins for distal appendage assembly and basal body docking. Finally, we show that mammalian centrioles require another component, Moonraker (MNR), to recruit OFD1, FOPNL, and CEP90, which will then recruit the distal appendage proteins CEP83, CEP89, and CEP164. Altogether, we propose that this OFD1, FOPNL, and CEP90 functional module is required to determine in mammalian cells the future position of distal appendage proteins.