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PubMed1985

Abnormal cilia in the small airways of mice induced by bleomycin.

The frequency and types of abnormal cilia in the small airways before and after parenteral administration of bleomycin were examined by transmission electron microscopy. Bleomycin was injected subcutaneously at a dose of 40 mg/kg twice weekly for 6 weeks. Bronchioles less than 0.1 mm in diameter from animals sacrificed 1 day after a single dose, 1 day after three doses, 3 days after 8 doses, and 13 days after 12 doses were selected for evaluation. Although ciliated cells proper did not show pronounced alterations, abnormal cilia such as swollen cilia, compound cilia, and cilia with abnormal axonemes frequently occurred. Repeated injections did not necessarily induce much more abnormal cilia than one dose. The results suggested that ciliated cells remain undamaged and that normal cilia can be restored. The specific type of abnormal cilia induced by bleomycin was not identified.

Animals↗

PubMed2004

Neuronal primary cilia: a review.

Primary cilia in neurons have often been regarded as rare, vestigial curiosities. However, neuronal cilia are now gaining recognition as ubiquitous organelles in the mammalian brain, raising speculation about what their functions may be. They might have some features tailored for the nervous system and others that serve needs shared by a spectrum of other cell types. Here we review clues from the literature and present new data supporting several possibilities for the significance of neuronal cilia. Our immunocytochemical results show regional heterogeneity in neuronal cilia. Brain regions nearer to the cerebral ventricles had longer cilia, suggesting that they might sense chemicals such as peptides, originating from cerebrospinal fluid. In mutant Tg737(orpk)mice, most brain regions appeared to be missing cilia. The importance of intraflagellar transport proteins establishes a functional link between neuronal cilia and other primary cilia.

Animals↗

PubMed2004

Cultured peritoneal mesothelial cells exhibit apical primary cilia.

This study examined primary cilia on cultured human and rabbit peritoneal mesothelial cells (PMC) and investigated factors that influence ciliary expression. Primary cilia were examined with indirect immunocytochemistry, laser scanning confocal microscopy and scanning electron microscopy. Ciliary expression was evaluated in cultures with or without l-cysteine (0.25 mM) or exposure to Ca(2+)-free Krebs-Ringer solution supplemented with EGTA, 0.5 mM. This treatment disrupted cell monolayer integrity. Cilia were counted and normalized to total cell counts using NIH image. Primary cilia were identified on both human and rabbit PMC. Cells treated with l-cysteine expressed significantly more cilia compared with monolayers deprived of l-cysteine. Exposure to Ca(2+)-free Krebs-Ringer solution significantly reduced cilia (5.9+/-1.0%, n=7). Although ciliary expression could be augmented with l-cysteine, approximately 60% of human PMC and 84% of rabbit PMC did not exhibit cilia. Together, these data show that monolayers of PMC express apical cilia that can be augmented with l-cysteine, independently of increased cell density.

Animals↗

PubMed2006

Cholangiocyte cilia detect changes in luminal fluid flow and transmit them into intracellular Ca2+ and cAMP signaling.

BACKGROUND & AIMS: Cholangiocytes have primary cilia extending from the apical plasma membrane into the ductal lumen. While the physiologic significance of cholangiocyte cilia is unknown, studies in renal epithelia suggest that primary cilia possess sensory functions. Here, we tested the hypothesis that cholangiocyte cilia are sensory organelles that detect and transmit luminal bile flow stimuli into intracellular Ca2+ ([Ca2+]i) and adenosine 3',5'-cyclic monophosphate (cAMP) signaling. METHODS: Scanning electron microscopy, transmission electron microscopy, and immunofluorescent confocal microscopy of rat isolated intrahepatic bile duct units (IBDUs) were used to detect and characterize cholangiocyte cilia. The fluid flow-induced changes in Ca2+ and cAMP levels in cholangiocytes of microperfused IBDUs were detected by epifluorescence microscopy and a fluorescence assay, respectively. RESULTS: In microperfused IBDUs, luminal fluid flow induced an increase in [Ca2+]i and caused suppression of the forskolin-stimulated cAMP increase. The fluid flow-induced changes in [Ca2+]i and cAMP levels were significantly reduced or abolished when cilia were removed by chloral hydrate or when ciliary-associated proteins polycystin-1 (a mechanoreceptor), polycystin-2 (a Ca2+ channel), and the Ca2+-inhibitable adenylyl cyclase isoform 6 were individually down-regulated by small interfering RNAs. CONCLUSIONS: Cholangiocyte cilia are sensory organelles containing polycystin-1, polycystin-2, and adenylyl cyclase isoform 6 through which luminal fluid flow affects both [Ca2+]i and cAMP signaling in the cell. The data suggest a new model for regulation of ductal bile secretion involving cholangiocyte cilia.

Animals↗

PubMed1995

Brain and respiratory cilia: the effect of temperature.

We have used a modified photodiode method to measure ciliary beat frequency of human neonatal cilia, and have developed techniques to allow similar measurements of rat brain cilial function. The effect of temperature change, within the physiological range, on neonatal human respiratory cilia and neonatal rat brain cilia was studied. The mean (SD) ciliary beat frequency of neonatal respiratory cilia at body temperature was 14 (1.1) Hz and that of rat brain cilia 18.9 (1.3) Hz. Respiratory cilial beat frequency decreased by 9.1% and brain cilia by 13% on cooling to 32 degrees C compared to normal body temperature. Beat frequency increased by 8.5% in respiratory samples and by 12% in brain samples on warming to 40 degrees C compared to the frequency at normal body temperature. The Q10 of human neonatal respiratory cilia was 1.2 and that of rat brain cilia 1.3.

Animals↗

PubMed1985

Structural heterogeneity of the axonemes of respiratory cilia and sperm flagella in normal men.

The ultrastructure of normal human cilia and flagella was examined and quantitatively assessed to determine the normal variations in the structure of the axoneme. Ciliated respiratory epithelial cells and spermatozoa from 10 normal, nonsmoking male volunteers who had normal semen parameters were fixed for electron microscopy. Tannic acid and MgSO4 were included during fixation to enhance, in particular, axonemal components. In 75 axonemal cross sections per sample, the number of outer doublet and central singlet microtubules, outer and inner dynein arms, and radial spokes were recorded. Statistical analysis of the results showed a marked reduction, from the expected value of nine, in the numbers of inner dynein arms (mean +/- SE, cilia, 5.31 +/- 0.13; sperm, 5.38 +/- 0.16) and radial spokes (cilia, 4.95 +/- 0.22; sperm, 5.80 +/- 0.19). The ideal axoneme with all its structural components was seen in only 0.13% of cilia and 0.80% of sperm tails. Significantly more doublet microtubules (P less than 0.05) and less central microtubules (P less than 0.01) and radial spokes (P less than 0.01) were seen in cilia than in sperm tail axonemes. Between subjects there was little variation in the mean number of a structure seen per axoneme. However, within each sample, the variation was considerably higher, particularly for the inner and outer dynein arms and radial spokes. The doublet microtubules had significantly greater standard deviations in the sperm tails compared with the cilia (P less than 0.01), and furthermore, a significantly greater number of sperm tails compared with cilia showed the incorrect number of doublet microtubules (P less than 0.02). In one semen sample, with normal semen analysis, 20% of the sperm tails showed incorrect numbers of doublet microtubules, ranging from 12 + 2 to 5 + 2 compared with only 1.3% in cilia from this subject. This study has demonstrated that the ideal axoneme is rarely seen even in normal samples, probably because of the technical difficulties in resolution and visualization, and stresses the need for thorough documentation of axonemal ultrastructure. This work provides a normal data base for comparison with patients who have chronic respiratory disease and suspected infertility.

Adult↗

PubMed1999

A novel WD40 protein, CHE-2, acts cell-autonomously in the formation of C. elegans sensory cilia.

To elucidate the mechanism of sensory cilium formation, we analyzed mutants in the Caenorhabditis elegans che-2 gene. These mutants have extremely short cilia with an abnormal posterior projection, and show defects in behaviors that are mediated by ciliated sensory neurons. The che-2 gene encodes a new member of the WD40 protein family, suggesting that it acts in protein-protein interaction. Analysis of mutation sites showed that both the amino-terminal WD40 repeats and the carboxyl-terminal non-WD40 domain are necessary for the CHE-2 function. CHE-2-tagged green fluorescent protein is localized at the cilia of almost all the ciliated sensory neurons. Expression of che-2 in a subset of sensory neurons of a che-2 mutant by using a heterologous promoter resulted in restoration of the functions and cilium morphology of only the che-2-expressing neurons. Thus, che-2 acts cell-autonomously. This technique can be used in the future for determining the function of each type of che-2-expressing sensory neuron. Using green fluorescent protein, we found that the extension of cilia in wild-type animals took place at the late embryonic stage, whereas the cilia of che-2 mutant animals remained always short during development. Hence, the abnormal posterior projection is due to the inability of cilia to extend, rather than degeneration of cilia once correctly formed. Expression of che-2 in a che-2 mutant under a heat shock promoter showed that the extension of cilia, surprisingly, can occur even at the adult stage, and that such cilia can function apparently normally in behavior.

Amino Acid Sequence↗

PubMed2006

Polycystin-2 traffics to cilia independently of polycystin-1 by using an N-terminal RVxP motif.

Primary cilia play a key role in the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD). The affected proteins, polycystin-1 (PC1) and polycystin-2 (PC2), interact with each other and are expressed in cilia. We found that COOH-terminal truncated PC2 (PC2-L703X), lacking the PC1 interaction region, still traffics to cilia. We examined PC2 expression in several tissues and cells lacking PC1 and found that PC2 is expressed in cilia independently of PC1. We used N-terminal deletion constructs to narrow the domain necessary for cilia trafficking to the first 15 amino acids of PC2 and identified a conserved motif, R6VxP, that is required for cilial localization. The N-terminal 15 amino acids are also sufficient to localize heterologous proteins in cilia. PC2 has endogenous cilia trafficking information and is present in cilia of cells lining cysts that result from mutations in PKD1.

Amino Acid Motifs↗

PubMed1983

Freeze-fracture analysis of membrane events during early neogenesis of cilia in Tetrahymena: changes in fairy-ring morphology and membrane topography.

A freeze-fracture analysis of early neogenesis of somatic and oral cilia of Tetrahymena was conducted using exponentially grown cultures and also cells induced to undergo oral reorganization. In this report, presumptive ciliary domains (PCDs), sites of future outgrowth of somatic cilia, are identified and their membrane structure is described in detail. The fairy ring, an array of membrane particles that occurs within the PCD and appears to be a precursor of the ciliary necklace, is described. A sequence of early stages in the formation of the ciliary necklace of somatic cilia is deduced from topographical information and membrane particle arrangements and numbers. Evidence is presented that basal bodies are seated at the cell surface prior to initiation of necklace assembly and a possible role for the basal body in necklace assembly is suggested. In dividing cells, new oral cilia grow out prior to orientation of cilia-parasomal sac complexes relative to cell axes. In dividing cells and during oral reorganization, new cilia also develop prior to their alignment into membranelles. Thus, growth of cilia is independent of their spatial orientation. Fairy rings were not observed during oral reorganization. During cell division, proliferation of new cilia is accompanied by the formation of a network of junctions between a cortical system of membranous cisternae, the cortical 'alveoli'. These interalveolar junctions may serve as tracks for early positioning and orientation of new oral basal bodies.

Animals↗

PubMed1986

A partially purified preparation of isolated chemosensory cilia from the olfactory epithelium of the bullfrog, Rana catesbeiana.

Cilia at the tips of dendritic processes of olfactory receptor cells are the sites of initial recognition and transduction events in olfactory reception. We have detached cilia from the olfactory epithelium of the bullfrog, Rana catesbeiana, via a calcium shock and partially purified them in high yield (226 +/- 19 micrograms protein/frog, n = 14) by sucrose gradient centrifugation. The cilia appear to undergo osmotic lysis during the isolation procedure, forming isolated axonemal structures and ciliary plasma membrane vesicles with diameters of 100-500 nm and an internal volume of 2.3 +/- 0.5 microliter/mg protein. PAGE in SDS reveals approximately 30 protein bands, among which cytoskeletal components, such as tubulin and actin, are readily identifiable by immunoblotting. Approximately 15 glycoprotein bands reactive with concanavalin A are discernible with major glycopeptides at apparent molecular weights of 56-65, 95, and 116 kDa. In contrast to olfactory cilia, respiratory cilia, isolated from the palate of the frog, do not contain the prominent glycopeptides observed for olfactory cilia. The 56-65 kDa glycopeptide region reacts with antiserum against chick kidney, Na+/K+-ATPase, and contains the beta subunit of this enzyme. In addition, we have identified the alpha and beta subunits of a guanine nucleotide-binding protein (G-protein) in the olfactory cilia preparation. This preparation of isolated olfactory cilia from Rana catesbeiana represents a readily accessible model system for studies of initial events in chemosensory recognition and signal transduction in the olfactory system.

Animals↗

PubMed1983

Blind quantitative electron microscopy of cilia from patients with primary ciliary dyskinesia and from normal subjects.

Cilia from the nasal cavity of 27 patients with congenital ciliary dyskinesia (immotile cilia syndrome) and of 15 normal persons were examined by transmission electron microscopy. The patients had on average a significantly higher number of cilia with absent or markedly reduced numbers of outer or inner dynein arms, of cilia with various types of abnormal configuration of the microtubules, except for compound cilia, and of cilia with an abnormally large variation of the beating axis. Compound cilia were equally frequent in patients and controls. The main structural defect in 9 patients was absent or abnormality low number of outer dynein arms in 4 in conjunction with an abnormally large axis variation and in 1 with a markedly reduced number of inner dynein arms also in 1 with supernumerous axonemal microtubules also. In 9 patients the main defects were abnormal configuration of the axonemal microtubules and a large axis variation. Seven of these had eccentrically located central pairs of microtubules and radial spoke defects, 5 in conjunction with abnormally low numbers of inner dynein arms. In one patient there were various types of abnormal configuration of the axonemal microtubules together with absent inner dynein arms, in another cilia with supernumerous microtubules only were present. The only abnormal finding in 1 patient was an extreme variation in the ciliary axes. Completely normal ciliary ultrastructure was found in 8 patients.

Adolescent↗

PubMed1978

[Cilia abnormalities in chronic maxillary sinusitis. a transmission (TEM) and scanning (SEM) electron microscopic investigation (author's transl)].

In the resistance of respiratory diseases the mucociliary clearance is a very important factor. Among them the cilia play a decisive role. The normal structure and some variations of the cilia in the maxillary sinus are described using transmission and scanning electron microscopy. The following cilia abnormalities were observed: cilia with a single axonema and excess cytoplasmic matrix; compound cilia and giant cilia with 2-4 and more complete or incomplete axonemata; development of cells, which have secretory granules like goblet cells and cilia like normal ciliated cells. Further the outgrowing of new cilia is shown in the SEM.

Cilia↗

PubMed1996

Morphologic and motility changes of nasal cilia in primary culture caused by Haemophilus influenzae.

We focused on the pathogenicity of otitis media with effusion (OME) with respect to the susceptibility of the upper respiratory tract mucosa to Haemophilus influenzae. Human nasal polyps in outgrowth culture were used to study H influenzae disturbance of the ciliary beat frequency (CBF) and the morphology of cilia. The CBF of control primary culture was 11.7 +/- 2.7 Hz. The CBF slowed down significantly, to 8.5 +/- 5.7 Hz, after incubation with the filtrate of 10(8) CFU/mL of H influenzae, and to 4.1 +/- 4.1 Hz with a suspension of 10(8) CFU/mL of H influenzae (p<.05). In the morphologic study, we classified the shapes of the cilia into five types: normal cilia, immotile cilia, swollen cilia, clumped cilia, and exfoliated ciliated cells. The abnormal shapes of cilia increased after incubation with the suspension or the filtrate of H influenzae. By scanning electron microscopy, we saw that aggregated bacteria tended to associate with cilia. Thus, the findings suggest that H influenzae disturbs the ciliary clearance of nasal cells and makes them more susceptible to infections.

Adult↗

PubMed2000

Intraocular cilia associated with perforating injury.

PURPOSE: To report a case series of penetrating injury complicated by occurrence of intraocular cilia. METHODS: Retrospective analysis of charts of 11 eyes of 11 patients with penetrating injury and intraocular cilia, presenting between September 1978 and November 1998. Ten eyes underwent surgery for trauma-related problems such as cataract, vitritis, retinal detachment etc., at which time intraocular cilia were removed. One eye did not have surgery and continues to harbour cilia at the posterior perforation site. RESULTS: Metallic wire was responsible for injury in 6 of 11 eyes with intraocular cilia. Five eyes had significant intraocular inflammation. The cilia were located in the anterior segment in 4 eyes; in the posterior segment in 6 eyes and in both in one eye. At the last follow up, 72.7% had 6/18 or better vision. Poor vision in the rest was due to recurrent retinal detachment (2 eyes) and macular scarring (1 eye). CONCLUSION: Intraocular cilia are more commonly associated with injury by a metallic wire. The presentation and management of an injured eye does not seem to be influenced by the presence of cilia in the eye.

Adolescent↗

PubMed1998

Effect of viscosity on metachrony in mucus propelling cilia.

In the present work we report that increasing the viscosity of the medium caused not only a decrease in the ciliary beat frequency but also changes in the metachrony and correlation between cilia. The study was performed using double and triple simultaneous photoelectric measurements on cultured ciliary cells from the frog esophagus in the viscosity range of 1-2,000 cp. We observed that increasing the viscosity intensified the fluctuations in all the measured parameters. Ciliary beat frequency decreased moderately. Even at quite high viscosities (circa 2000 cp.), cilia were still active with beating frequencies of 3-5 Hz. In addition, the degree of correlation between cilia parallel to the effective stroke direction (ESD) decreased, while that perpendicular to the ESD at a low range of viscosities remained unchanged and even increased at high viscosities. Medium viscosities in the range of 30-1,500 cp. altered the metachronal wave properties of cultured frog esophagus. The metachronal wavelength increased by up to 50%, and the wave direction changed towards more orthoplectic type of coordination. According to our recently suggested model [Gheber and Priel, 1990: Cell Motil. Cytoskeleton 16:167-181], these effects can be explained by a decrease in the temporal asymmetry of the ciliary beat. Since similar results were observed in water propelling cilia of Paramecium subjected to medium viscosity ranges of up to 40 cp. [Machemer, 1972: J. Exp. Biol. 57:239-259], we conclude that hydrodynamic interactions govern the metachronal wave properties of both mucus and water propelling cilia, though mucus propelling cilia, with their better adaptation to increased load, are affected at much higher viscosities than water propelling cilia.

Animals↗

PubMed1998

Myosin VIIa as a common component of cilia and microvilli.

The distribution of myosin VIIa, which is defective or absent in Usher syndrome 1B, was studied in a variety of tissues by immunomicroscopy. The primary aim was to determine whether this putative actin-based mechanoenzyme is a common component of cilia. Previously, it has been proposed that defective ciliary function might be the basis of some forms of Usher syndrome. Myosin VIIa was detected in cilia from cochlear hair cells, olfactory neurons, kidney distal tubules, and lung bronchi. It was also found to cofractionate with the axonemal fraction of retinal photoreceptor cells. Immunolabeling appeared most concentrated in the periphery of the transition zone of the cilia. This general presence of a myosin in cilia is surprising, given that cilia are dominated by microtubules, and not actin filaments. In addition to cilia, myosin VIIa was also found in actin-rich microvilli of different types of cell. We conclude that myosin VIIa is a common component of cilia and microvilli.

Animals↗

PubMed1990

Identification of surface components of mammalian respiratory tract cilia.

Cilia isolation methods were modified to retain respiratory tract ciliary membranes and to identify accessible surface components. Prior to isolation of cilia, halves of cow tracheae were treated with the extended spacer arm analog of N-hydroxysuccinimido-biotin (NHS-LC-biotin) to label accessible membrane constituents. Mechanical disruption of the epithelium and substitution of CHAPS for Triton X-100 provided a good yield of cilia with membranes and with minimal contamination. Subsequent extraction of these cilia with Triton X-100 solubilized the membranes and released soluble matrix proteins. Proteins of membrane + matrix and axoneme fractions were analyzed after electrophoresis in sodium dodecyl sulfate polyacrylamide gels. The major biotin-labeled components in the membrane + matrix fraction were 105, 98, and 92 kd, were glycosylated, and remained with reconstituted, pelleted membrane vesicles along with the major non-biotinylated protein at 51 kd. Other membrane + matrix proteins at 126 and 76 kd bound streptavidin even from nonlabeled trachea, but remained soluble. Several biotin-labeled proteins distinct from those in the membrane fraction remained with Triton X-100-extracted axonemes. Streptavidin-colloidal-gold (SAG) particles appeared to bind randomly along the length of cilia. The peripheral join between A and B microtubules was a predominant nonspecific location of SAG on axonemes. Axonemes with biotin label also bound significant numbers of SAG to outer dynein arms, confirming the streptavidin reaction with separated proteins on transfers. These results suggest close association of the membrane with the axoneme in respiratory tract cilia and a membrane composition somewhat different from protozoan cilia.

Animals↗

PubMed1986

Phenotypic switching to long cilia effected by various proteases: results with Dendraster excentricus and Stronglyocentrotus purpuratus blastulae.

Incubation in trypsin effects a phenotypic switch from short to long cilia (greater than 30 micron) in hatched blastulae of the sea urchin, Arbacia punctulata. To determine how trypsin causes such a switch we tested whether the phenomenon was unique to the species, Arbacia, and to the protease, trypsin. With two other echinoderm species, the sand dollar, Dendraster excentricus, and the sea urchin, Strongylocentrotus purpuratus, trypsin incubation increased the percentage of long cilia. During incubation of D. excentricus in trypsin, the percentage of long cilia increased progressively from the normal 10% long cilia of the apical tuft to 45-50% long cilia covering 1/2-3/4 of the embryo. With S. purpuratus blastulae, however, the percentage of long cilia was lower (32-40%) and the results were more variable. Of the additional proteases tested with D. excentricus, elastase was more effective than trypsin in terms of the percentage of long cilia (58%), the mean length, and the broad distribution of lengths formed. Thermolysin was about as effective as trypsin but chymotrypsin was much less so. Thus, increases in ciliary length were not unique to a particular echinoderm species or to incubation in trypsin. The magnitude of the change in length distribution, however, was species- and enzyme-dependent. An extracellular or membrane component with differential susceptibility to various proteases may, therefore, be involved in altering ciliary length.

Animals↗