Clinical spectrum of primary ciliary dyskinesia in childhood

Although the triad of bronchiectasis, sinusitis and situs inversus was first described by Kartagener in 1933, the clinical spectrum of primary ciliary dyskinesia is still under investigation. Heterotaxy defects as well as upper and lower respiratory tract symptoms are the main manifestations in childhood. It is now recognized that situs inversus is encountered in only half of patients. The first lower respiratory symptoms may be present from infancy as neonatal respiratory distress. The most common lower airway manifestations are chronic wet cough, recurrent pneumonia and therapy resistant wheezing. Patients are at risk of developing bronchiectasis which may even be the presenting finding due to delayed diagnosis. Upper respiratory tract infections such as nasal congestion, nasal drainage and recurrent sinusitis as well as otologic manifestations such as otitis media or otorrhea with conductive hearing loss are also often encountered. It seems that the type of ciliary ultrastructure defects and the involved mutated genes are associated to some extent to the clinical profile. The disease, even in nowadays, is not recognized at an early age and the primary care clinician should have knowledge of its clinical spectrum in order to select appropriately the children who need further investigation for the diagnosis of this disorder.

Biomimetic Cilia Based on MEMS Technology

A review on the research of Micro Electromechanical Systems （MEMS） technology based biomimetic cilia is presented. Biomimetic cilia, enabled by the advancement of MEMS technology, have been under dynamic development for the past decade. After a brief description of the background of cilia and MEMS technology, different biomimetic cilia applications are reviewed. Biomimetic cilia micro-actuators, including micromachined polyimide bimorph biomimetic cilia micro-actuator, electro-statically actuated polymer biomimetic cilia micro-actuator, and magnetically actuated nanorod array biomimetic cilia micro-actuator, are presented. Subsequently micromachined underwater flow biomimetic cilia micro-sensor is studied, followed by acoustic flow micro-sensor. The fabrication of these MEMS-based biomimetic cilia devices, characterization of their physical properties, and the results of their application experiments are discussed.

Effect of Cilia Orientation in Metachronal Transport of Microparticles

A biomimetic approach is used to generate a directed transversal transportation of micron-sized particles in liquids based on the principle of cilia-type arrays in coordinated motion. Rows of flaps mimicking planar cilia are positioned off-centre along an array of cavities covered with membranes that support the flaps. These membranes are deflected from a concave to a convex shape and vice versa by pneumatic actuation applying positive and negative pressures (relative to the ambient) inside the cavities. As a result, the flap on top of the membrane tilts to the left or right within such a pressure cycle, performing a beat stroke. Since each cavity can be addressed in the device individually and in rapid succession, waves of coordinated flap motion can be run along the wall. Such metachronal waves are generated and transport of particles along the cilia surface is achieved in both symplectic and antiplectic direction. It is shown that the initial tilt of the flaps relative to the wall-normal determines the direction of transport.

Rheological fluid motion in tube by metachronal waves of cilia

This paper presents a theoretical study of a non-linear rheological fluid transport in an axisymmetric tube by cilia. An attempt has been made to explain the role of cilia motion in the transport of fluid through the ductus efferent of the male reproductive tract. The Ostwald-de Waele power-law viscous fluid is considered to represent the rheological fluid. We analyze pumping by means of a sequence of cilia beats from rowto-row of cilia in a given row of cells and from one row of cells to the next(metachronal wave movement). For this purpose, we consider the conditions that the corresponding Reynolds number is small enough for inertial effects to be negligible, and the wavelengthto-diameter ratio is large enough so that the pressure can be considered uniform over the cross section. Analyses and computations of the fluid motion reveal that the time-average flow rate depends on ε, a non-dimensional measure involving the mean radius a of the tube and the cilia length. Thus, the flow rate significantly varies with the cilia length.Moreover, the flow rate has been reported to be close to the estimated value 6 × 10ml/h for human efferent ducts if ε is near 0.4. The estimated value was suggested by Lardner and Shack(Lardner, T. J. and Shack, W. J. Cilia transport. Bulletin of Mathematical Biology, 34, 325–335(1972)) for human based on the experimental observations of flow rates in efferent ducts of other animals, e.g., rat, ram, and bull. In addition, the nature of the rheological fluid, i.e., the value of the fluid index n strongly influences various flow-governed characteristics. An interesting feature of this paper is that the pumping improves the thickening behavior for small values of ε or in free pumping(?P = 0) and pumping(?P > 0) regions.

Cilia containing 9+2 structures grown from immortalized cells

Cilia depend on their highly differentiated structure, a 9 ＋ 2 arrangement, to remove particles from the lung and to transport reproductive cells. Immortalized cells could potentially be of great use in cilia research. Immortalization of cells with cilia structure containing the 9 ＋ 2 arrangement might be able to generate cell lines with such cilia structure. How- ever, whether immortalized cells can retain such a highly differentiated structure remains unclear. Here we demonstrate that （1） using Ela gene transfection, tracheal cells are immortalized; （2） interestingly, in a gel culture the immortalized cells form spherical aggregations within which a lumen is developed; and （3） surprisingly, inside the aggregation, cilia containing a 9 ＋ 2 arrangement grow from the cell＇s apical pole and protrude into the lumen. These results may influence future research in many areas such as understanding the mechanisms of cilia differentiation, cilia generation in other existing cell lines, cilia disorders, generation of other highly differentiated structures besides cilia using the gel culture, immortalization of other ciliated cells with the Ela gene, development of cilia motile function, and establishment of a research model to provide uniform ciliated cells.

Bilateral medulloepithelioma of the ciliary body:a case report

Dear Editor,We present an exceptionally rare case about bilateral medulloepithelioma of the ciliary body.This case was approved by Ethics Committee of Capital Medical University.Written informed consent was obtained from the patients.Discovering leukocoria in both eyes and proptosis in right eye for 2mo by parents in a 4.5-month-old boy.He had undergone no treatment elsewhere except magnetic resonance imaging examination before coming to Beijing Tongren Hospital.

Case report: Metastatic adenocarcinoma of the lung with filiform “ciliated” tumor cells in the cerebrospinal fluid

Occurrence of cilia on the cell surface is usually considered evidence of a non-neoplastic process. Rarely, ciliated malignant tumors cells have been reported in pleural and ascitic fluids from ovarian and endometrial adenocarcinomas, though not from the cerebrospinal fluid (CSF) in association with pulmonary adenocarcinoma. We now present a case report of a patient who initially presented with neurologic symptoms. A CSF specimen revealed atypical cells with peripheral cilia and some cytoplasmic pigment. Cytologic, morphologic, and immunohistochemical analyses established this to be a metastatic adenocarcinoma of pulmonary origin with metastases to the meninges, pelvis, and the vertebrae. Cilia are generally the antithesis of malignancy as their presence is considered to be evidence of proper regulation of the cell cycle within a well-differentiated cell. This case offers the first described example of malignant ciliated cells derived from a metastatic lung adenocarcinoma. An awareness of this unusual presentation should aid in diagnosis and management when similar situations are prospectively encountered.

De novo identification of mammalian ciliary motility proteins using cryo-EM

Dynein-decorated doublet microtubules(DMTs)are critical components of the oscillatory molecular machine of cilia,the axoneme,and have luminal surfaces patterned periodically by microtubule inner proteins(MIPs).Here we present an atomic model of the 48-nm repeat of a mammalian DMT,derived from a cryoelectron microscopy(cryo-EM)map of the complex isolated from bovine respiratory cilia.

Diagnosis and treatment of male infertility associated with immotile cilia syndrome:a report of 6 cases

Objective:To investigate the clinical characteristics,diagnosis and treatment of male infertility associated with immotile cilia syndrome(ICS). Methods:The clinical data of six cases of male infertility associated with ICS were reviewed retrospectively. Results:The clinical features in all cases included chronic or recurrent infections of the upper and lower airways and male infertility.Sinusitis,bronchitis and bronchiectasis were found in all cases and situs inversus totalis found in two cases.Sex hormone levels,chromosome karyotype and Y chromosome microdeletion(AZF) in all cases were normal.All cases were diagnosed as severe asthenospermia by routine semen analysis.Five cases had no motile spermatozoa in semen,while there were less than 0.2%of motile sperm in one case.The total sperm count and sperm viability were normal in four cases and there were very few immotile sperm in two cases.Transmission electron microscopic examination of sperm flagellum revealed disarrangement or a partial absence of 9+2 microtubules and/or an absence of the dynein arms in six cases.The bronchial cilia in one case showed to be devoid of inner dynein arms.Five cases underwent six intracytoplasmic sperm injection(ICSI) cycles and the rates of fertilization,embryo cleavage and good quality embryos were 50.0%,69.2%and 55.6%,respectively.Two clinical pregnancies and one chemical pregnancy were achieved,with one birth of a healthy baby boy. Conclusions:The ultrastructural defect of cilia or flagellum is the most important diagnostic criteria of ICS. ICSI is an effective treatment for male infertility associated with ICS.

ccdc141 is required for left-right axis development by regulating cilia formation in the Kupffer's vesicle of zebrafish

Laterality is a crucial physiological process intricately linked to the cilium-centrosome complex during embryo development.Defects in the process can result in severe organ mispositioning.Coiled-coil domain containing 141(CCDC141)has been previously known as a centrosome-related gene,but its role in left-right(LR)asymmetry has not been characterized.In this study,we utilize the zebrafish model and human exome analysis to elucidate the function of ccdc141 in laterality defects.The knockdown of ccdc141 in zebrafish disrupts early LR signaling pathways,cilia function,and Kupffer's vesicle formation.Unlike ccdc141-knockdown embryos exhibiting aberrant LR patterns,ccdc141-null mutants show no apparent abnormality,suggesting a genetic compensation response effect.In parallel,we observe a marked reduction inα-tubulin acetylation levels in the ccdc141 crispants.The treatment with histone deacetylase(HDAC)inhibitors,particularly the HDAC6 inhibitor,rescues the ccdc141 crispant phenotypes.Furthermore,exome analysis of 70 patients with laterality defects reveals an increased burden of CCDC141 mutations,with in-vivo studies verifying the pathogenicity of the patient mutation CCDC141-R123G.Our findings highlight the critical role of ccdc141 in ciliogenesis and demonstrate that CCDC141 mutations lead to abnormal LR patterns,identifying it as a candidate gene for laterality defects.

The role of primary cilia in mechanical transmission of osteocyte based on a 3D finite element model

The primary cilium,as a mechanical receptor of osteocytes,participates in the regulation of osteocyte mechanosensitivity.However,how the length of osteocyte primary cilia changes with fluid shear stress(FSS)are unclear,and how the mechanical transmission within osteocytes altered by primary cilia is not well understood yet.Therefore,the ciliary length changes of osteocyte under 15dyn/cm2 of FSS were experimentally detected,and then 3D finite element models of osteocyte primary cilia containing the basal body and axoneme were built.The results showed that(1)The ciliary length of the CON group,FSS 1h,and FSS 6h were 3.71±1.34μm,3.79±1.04μm,and 1.24±0.73μm respectively,indicating the different durations of FSS might lead to the adaptive changes of cilium length.The calculations showed(2)when the ciliary length became shorter with the ciliary angle stayed the same,the deformation and stress of the cell membrane and membrane skeleton was increased.However,the deformation and stress of the cilia membrane,basal body,the rotation angles of basal body were decreased,and those of cytoplasm,cytoskeleton,actin cortex and nucleus were also decreased;(3)With the decrease of the ciliary angle,the deformation and stress of the cilia membrane,basal body,as well as the rotation angles of basal body were increased.Those of the cytoplasm,cytoskeleton,actin cortex,and nucleus were also increased except the cell membrane and membrane skeleton.The calculation results suggested the length and angle of the primary cilia,the deformation and stress of intracellular structures in osteocyte were altered with ciliary basal body,indicated the connection between the basal body and cytoskeleton may be a key factor that affected the mechanical transport in osteocytes across the cell membrane.This finally promoted the adaptive change of ciliary length under FSS.

Dynein axonemal heavy chain 10 deficiency causes primary ciliary dyskinesia in humans and mice

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.

Lack of CFAP54 causes primary ciliary dyskinesia in a mouse model and human patients

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.

Cilia and ciliopathies:From Chlamydomonas and beyond

The biological function of motile cilia/flagella has long been recognized. The non-motile primary cilium, once regarded as a vestigial organelle, however, has been found recently to play unexpected roles in mammalian physiology and development. Defects in cilia have profound impact on human health. Diseases related to cilia, collectively called ciliopathies include male infertility, primary cilia dyskinesia, renal cyst formation, blindness, polydactyly, obesity, hypertension, and even mental retardation. Our current understanding of cilia and ciliopathies has been fueled by basic research employing various model organisms including Chlamydomonas, a unicellular green alga. This review article provides a general introduction to the cell biology of cilia and an overview of various cilia-related diseases.

Primary cilia mediate Klf2-dependant Notch activation in regenerating heart

Unlike adult mammalian heart,zebrafish heart has a remarkable capacity to regenerate after injury.Previous study has shown Notch signaling activation in the endocardium is essential for regeneration of the myocardium and this activation is mediated by hemodynamic alteration after injury,however,the molecular mechanism has not been fully explored.In this study we demonstrated that blood flow change could be perceived and transmitted in a primary cilia dependent manner to control the hemodynamic responsive klf2 gene expression and subsequent activation of Notch signaling in the endocardium.First we showed that both homologues of human gene KLF2 in zebrafish,klf2a and klf2b,could respond to hemodynamic alteration and both were required for Notch signaling activation and heart regeneration.Further experiments indicated that the upregulation of klf2 gene expression was mediated by endocardial primary cilia.Overall,our findings reveal a novel aspect of mechanical shear stress signal in activating Notch pathway and regulating cardiac regeneration.

Primary cilia in hard tissue development and diseases

Bone and teeth are hard tissues.Hard tissue diseases have a serious effect on human survival and quality of life.Primary cilia are protrusions on the surfaces of cells.As antennas,they are distributed on the membrane surfaces of almost all mammalian cell types and participate in the development of organs and the maintenance of homeostasis.Mutations in cilium-related genes result in a variety of developmental and even lethal diseases.Patients with multiple ciliary gene mutations present overt changes in the skeletal system,suggesting that primary cilia are involved in hard tissue development and reconstruction.Furthermore,primary cilia act as sensors of external stimuli and regulate bone homeostasis.Specifically,substances are trafficked through primary cilia by intraflagellar transport,which affects key signaling pathways during hard tissue development.In this review,we summarize the roles of primary cilia in long bone development and remodeling from two perspectives:primary cilia signaling and sensory mechanisms.In addition,the cilium-related diseases of hard tissue and the manifestations of mutant cilia in the skeleton and teeth are described.We believe that all the findings will help with the intervention and treatment of related hard tissue genetic diseases.

Ccdc57 is required for straightening the body axis by regulating ciliary motility in the brain ventricle of zebrafish

Recently,cilia defects have been proposed to contribute to scoliosis.Here,we demonstrate that coiled-coil domain-containing 57(Ccdc57)plays an essential role in straightening the body axis of zebrafish by regulating ciliary beating in the brain ventricle(BV).Zygotic ccdc57(Zccdc57)mutant zebrafish developes scoliosis without significant changes in their bone density and calcification,and the maternal-zygotic ccdc57(MZccdc57)mutant embryos display curved bodies since the long-pec stage.The expression of ccdc57 is enriched in ciliated tissues and immunofluorescence analysis reveals colocalization of Ccdc57-HA with acetylated a-tubulin,implicating it in having a role in ciliary function.Further examination reveals that it is the coordinated cilia beating of multiple cilia bundles(MCB)in the MZccdc57 mutant embryos that is affected at 48 hours post fertilization,when the compromised cerebrospinal fluid flow and curved body axis have already occurred.Either ccdc57 m RNA injection or epinephrine treatment reverses the spinal curvature in MZccdc57 mutant larvae from ventrally curly to straight or even dorsally curly and significantly upregulates urotensin signaling.This study reveals the role of ccdc57 in maintaining coordinated cilia beating of MCB in the BV.

Small GTPases and cilia

Small GTPases are key molecular switches that bind and hydrolyze GTP in diverse membrane-and cytoskeletonrelated cellular processes.Recently,mounting evidences have highlighted the role of various small GTPases,including the members in Arf/Arl,Rab,and Ran subfamilies,in cilia formation and function.Once overlooked as an evolutionary vestige,the primary cilium has attracted more and more attention in last decade because of its role in sensing various extracellular signals and the association between cilia dysfunction and a wide spectrum of human diseases,now called ciliopathies.Here we review recent advances about the function of small GTPases in the context of cilia,and the correlation between the functional impairment of small GTPases and ciliopathies.Understanding of these cellular processes is of fundamental importance for broadening our view of cilia development and function in normal and pathological states and for providing valuable insights into the role of various small GTPases in disease processes,and their potential as therapeutic targets.

Cilia in cell signaling and human disorders

One of the most widespread cellular organelles in nature is cilium,which is found in many unicellular and multicellular organisms.Formerly thought to be a mostly vestigial organelle,the cilium has been discovered in the past several decades to play critical motile and sensory roles involved in normal organogenesis during development.The role of cilia has also been implicated in an ever increasing array of seemingly unrelated human diseases,including blindness,kidney cysts,neural tube defects and obesity.In this article we review some of the recent developments in research on cilia,and how defects in ciliogenesis and function can give rise to developmental disorders and disease.

A Cilia-inspired Closed-loop Sensor-actuator Array

Cilia are finger-like cell-surface organelles that are used by certain varieties of aquatic unicellular organisms for motility, sensing and obj ect manipulation. Initiated by internal generators and external mechanical and chemical stimuli, coordinated undulations of cilia lead to the motion of a fluid surrounding the organism. This motion transports micro-particles towards an oral cavity and provides motile force. Inspired by the emergent properties of cilia possessed by the pond organism P. caudatum, we propose a novel smart surface with closed-loop control using sensor-actuators pairings that can manipulate objects. Each vibrating motor actuator is controlled by a localised microcontroller which utilises proximity sensor information to initiate actuation. The circuit boards are designed to be plug-and-play and are infinitely up-scalable and reconfigurable. The smart surface is capable of moving objects at a speed of 7.2 millimetres per second in forward or reverse direction. Further development of this platform will include more anatomically similar biomimetic cilia and control.