scholarly journals SARS-CoV-2 infection induces the dedifferentiation of multiciliated cells and impairs mucociliary clearance

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rémy Robinot ◽  
Mathieu Hubert ◽  
Guilherme Dias de Melo ◽  
Françoise Lazarini ◽  
Timothée Bruel ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Mucociliary Clearance ◽  
Bronchial Epithelium ◽  
Lung Parenchyma ◽  
Ultrastructural Level ◽  
Epithelial Barrier Function ◽  
Multiciliated Cells ◽  
Motile Cilia ◽  
Cell Mobilization

AbstractUnderstanding how SARS-CoV-2 spreads within the respiratory tract is important to define the parameters controlling the severity of COVID-19. Here we examine the functional and structural consequences of SARS-CoV-2 infection in a reconstructed human bronchial epithelium model. SARS-CoV-2 replication causes a transient decrease in epithelial barrier function and disruption of tight junctions, though viral particle crossing remains limited. Rather, SARS-CoV-2 replication leads to a rapid loss of the ciliary layer, characterized at the ultrastructural level by axoneme loss and misorientation of remaining basal bodies. Downregulation of the master regulator of ciliogenesis Foxj1 occurs prior to extensive cilia loss, implicating this transcription factor in the dedifferentiation of ciliated cells. Motile cilia function is compromised by SARS-CoV-2 infection, as measured in a mucociliary clearance assay. Epithelial defense mechanisms, including basal cell mobilization and interferon-lambda induction, ramp up only after the initiation of cilia damage. Analysis of SARS-CoV-2 infection in Syrian hamsters further demonstrates the loss of motile cilia in vivo. This study identifies cilia damage as a pathogenic mechanism that could facilitate SARS-CoV-2 spread to the deeper lung parenchyma.

scholarly journals SARS-CoV-2 infection damages airway motile cilia and impairs mucociliary clearance

2020 ◽  
Author(s):  
Rémy Robinot ◽  
Mathieu Hubert ◽  
Guilherme Dias de Melo ◽  
Françoise Lazarini ◽  
Timothée Bruel ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Mucociliary Clearance ◽  
Bronchial Epithelium ◽  
Lung Parenchyma ◽  
Ultrastructural Level ◽  
Damage Analysis ◽  
Epithelial Barrier Function ◽  
Motile Cilia ◽  
Cell Mobilization

ABSTRACTUnderstanding how SARS-CoV-2 spreads within the respiratory tract is important to define the parameters controlling the severity of COVID-19. We examined the functional and structural consequences of SARS-CoV-2 infection in a reconstituted human bronchial epithelium model. SARS-CoV-2 replication caused a transient decrease in epithelial barrier function and disruption of tight junctions, though viral particle crossing remained limited. Rather, SARS-CoV-2 replication led to a rapid loss of the ciliary layer, characterized at the ultrastructural level by axoneme loss and misorientation of remaining basal bodies. The motile cilia function was compromised, as measured in a mucociliary clearance assay. Epithelial defense mechanisms, including basal cell mobilization and interferon-lambda induction, ramped up only after the initiation of cilia damage. Analysis of SARS-CoV-2 infection in Syrian hamsters further demonstrated the loss of motile cilia in vivo. This study identifies cilia damage as a pathogenic mechanism that could facilitate SARS-CoV-2 spread to the deeper lung parenchyma.

scholarly journals Synchronization of mammalian motile cilia in the brain with hydrodynamic forces

2019 ◽  
Author(s):  
Nicola Pellicciotta ◽  
Evelyn Hamilton ◽  
Jurij Kotar ◽  
Marion Faucourt ◽  
Nathalie Degehyr ◽  
...  
Keyword(s):  
Mechanistic Model ◽  
Hydrodynamic Forces ◽  
Coordination Mechanism ◽  
Mammalian Brain ◽  
Similar Frequency ◽  
Multiciliated Cells ◽  
Motile Cilia ◽  
External Flows ◽  
The Brain

Motile cilia are widespread across the animal and plant kingdoms, displaying complex collective dynamics central to their physiology. Their coordination mechanism is not generally understood, with pre-vious work mainly focusing on algae and protists. We study here the synchronization of cilia beat in multiciliated cells from brain ven-tricles. The response to controlled oscillatory external flows shows that strong flows at a similar frequency to the actively beating cilia can entrain cilia oscillations. We find that the hydrodynamic forces required for this entrainment strongly depend on the number of cilia per cell. Cells with few cilia (up to five) can be entrained at flows comparable to the cilia-driven flows reported in vivo. Simulations of a minimal model of cilia interacting hydrodynamically show the same trends observed in cilia. Our results suggest that hydrody-namic forces between cilia are sufficient to be the mechanism behind the synchronization of mammalian brain cilia dynamics.Significance StatementIt is shown experimentally, and also reproducing key qualitative results in a minimal mechanistic model simulated numerically, that in the motile cilia of the brain hydrodynamic forces of the magnitude that cilia themselves can generate are sufficient to establish the coordination of dynamics which is so crucial phys-iologically. This is the first experiment of its kind on multicilated cells, the key result is the unexpected importance of cilia num-ber per cell, with cells with fewer cilia much more susceptible to external flows. This finding changes the way in which we think about the question of collective cilia beating - it is not correct to simply examine isolated cilia and draw conclusions about the behaviour of cilia assemblies in multiciliated cells.

Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

1978 ◽  
Vol 36 (2) ◽  
pp. 650-651
Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo
Keyword(s):  
Direct Injection ◽  
Skin Pigmentation ◽  
Freeze Fracture ◽  
Pigment Granule ◽  
Time Lapse ◽  
Ultrastructural Level ◽  
Lanthanum Tracer ◽  
A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

scholarly journals Probing the Intracellular Bio-Nano Interface in Different Cell Lines with Gold Nanostars

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1183
Author(s):  
Cecilia Spedalieri ◽  
Gergo Péter Szekeres ◽  
Stephan Werner ◽  
Peter Guttmann ◽  
Janina Kneipp
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Early Stage ◽  
Protein Corona ◽  
Fibroblast Cell ◽  
Ultrastructural Level ◽  
Epithelial Cell Line ◽  
Animal Cells ◽  
Gold Nanostars

Gold nanostars are a versatile plasmonic nanomaterial with many applications in bioanalysis. Their interactions with animal cells of three different cell lines are studied here at the molecular and ultrastructural level at an early stage of endolysosomal processing. Using the gold nanostars themselves as substrate for surface-enhanced Raman scattering, their protein corona and the molecules in the endolysosomal environment were characterized. Localization, morphology, and size of the nanostar aggregates in the endolysosomal compartment of the cells were probed by cryo soft-X-ray nanotomography. The processing of the nanostars by macrophages of cell line J774 differed greatly from that in the fibroblast cell line 3T3 and in the epithelial cell line HCT-116, and the structure and composition of the biomolecular corona was found to resemble that of spherical gold nanoparticles in the same cells. Data obtained with gold nanostars of varied morphology indicate that the biomolecular interactions at the surface in vivo are influenced by the spike length, with increased interaction with hydrophobic groups of proteins and lipids for longer spike lengths, and independent of the cell line. The results will support optimized nanostar synthesis and delivery for sensing, imaging, and theranostics.

scholarly journals Protective Response in Experimental Paracoccidioidomycosis Elicited by Extracellular Vesicles Containing Antigens of Paracoccidioides brasiliensis

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1813
Author(s):  
Ludmila Matos Baltazar ◽  
Gabriela Fior Ribeiro ◽  
Gustavo J. Freitas ◽  
Celso Martins Queiroz-Junior ◽  
Caio Tavares Fagundes ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Treatment Effectiveness ◽  
Ex Vivo ◽  
Paracoccidioides Brasiliensis ◽  
Systemic Disease ◽  
Host Immune System ◽  
Antigen Delivery ◽  
Activated T Lymphocytes ◽  
Cell Mobilization

Paracoccidioidomycosis (PCM) is a systemic disease caused by Paracoccidioides spp. PCM is endemic in Latin America and most cases are registered in Brazil. This mycosis affects mainly the lungs, but can also spread to other tissues and organs, including the liver. Several approaches have been investigated to improve treatment effectiveness and protection against the disease. Extracellular vesicles (EVs) are good antigen delivery vehicles. The present work aims to investigate the use of EVs derived from Paracoccidioides brasiliensis as an immunization tool in a murine model of PCM. For this, male C57BL/6 were immunized with two doses of EVs plus adjuvant and then infected with P. brasiliensis. EV immunization induced IgM and IgG in vivo and cytokine production by splenocytes ex vivo. Further, immunization with EVs had a positive effect on mice infected with P. brasiliensis, as it induced activated T lymphocytes and NKT cell mobilization to the infected lungs, improved production of proinflammatory cytokines and the histopathological profile, and reduced fungal burden. Therefore, the present study shows a new role for P. brasiliensis EVs in the presence of adjuvant as modulators of the host immune system, suggesting their utility as immunizing agents.

scholarly journals The Structure–Properties–Cytotoxicity Interplay: A Crucial Pathway to Determining Graphene Oxide Biocompatibility

2021 ◽  
Vol 22 (10) ◽  
pp. 5401
Author(s):  
Marta Dziewięcka ◽  
Mirosława Pawlyta ◽  
Łukasz Majchrzycki ◽  
Katarzyna Balin ◽  
Sylwia Barteczko ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Defense Mechanisms ◽  
Physicochemical Analysis ◽  
Experimental Models ◽  
Acheta Domesticus ◽  
Synthesis Process ◽  
Synthesis Methods ◽  
Toxicity Potential ◽  
Potential Applications

Interest in graphene oxide nature and potential applications (especially nanocarriers) has resulted in numerous studies, but the results do not lead to clear conclusions. In this paper, graphene oxide is obtained by multiple synthesis methods and generally characterized. The mechanism of GO interaction with the organism is hard to summarize due to its high chemical activity and variability during the synthesis process and in biological buffers’ environments. When assessing the biocompatibility of GO, it is necessary to take into account many factors derived from nanoparticles (structure, morphology, chemical composition) and the organism (species, defense mechanisms, adaptation). This research aims to determine and compare the in vivo toxicity potential of GO samples from various manufacturers. Each GO sample is analyzed in two concentrations and applied with food. The physiological reactions of an easy model Acheta domesticus (cell viability, apoptosis, oxidative defense, DNA damage) during ten-day lasting exposure were observed. This study emphasizes the variability of the GO nature and complements the biocompatibility aspect, especially in the context of various GO-based experimental models. Changes in the cell biomarkers are discussed in light of detailed physicochemical analysis.

scholarly journals Differential effect of anesthetics on mucociliary clearance in vivo in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kyle S. Feldman ◽  
Eunwon Kim ◽  
Michael J. Czachowski ◽  
Yijen Wu ◽  
Cecilia W. Lo ◽  
...  
Keyword(s):  
Mucociliary Clearance ◽  
Defense Mechanism ◽  
Ex Vivo ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Wild Type ◽  
Sulfur Colloid ◽  
Ct System

AbstractRespiratory mucociliary clearance (MCC) is a key defense mechanism that functions to entrap and transport inhaled pollutants, particulates, and pathogens away from the lungs. Previous work has identified a number of anesthetics to have cilia depressive effects in vitro. Wild-type C57BL/6 J mice received intra-tracheal installation of 99mTc-Sulfur colloid, and were imaged using a dual-modality SPECT/CT system at 0 and 6 h to measure baseline MCC (n = 8). Mice were challenged for one hour with inhalational 1.5% isoflurane, or intraperitoneal ketamine (100 mg/kg)/xylazine (20 mg/kg), ketamine (0.5 mg/kg)/dexmedetomidine (50 mg/kg), fentanyl (0.2 mg/kg)/1.5% isoflurane, propofol (120 mg/Kg), or fentanyl/midazolam/dexmedetomidine (0.025 mg/kg/2.5 mg/kg/0.25 mg/kg) prior to MCC assessment. The baseline MCC was 6.4%, and was significantly reduced to 3.7% (p = 0.04) and 3.0% (p = 0.01) by ketamine/xylazine and ketamine/dexmedetomidine challenge respectively. Importantly, combinations of drugs containing fentanyl, and propofol in isolation did not significantly depress MCC. Although no change in cilia length or percent ciliation was expected, we tried to correlate ex-vivo tracheal cilia ciliary beat frequency and cilia-generated flow velocities with MCC and found no correlation. Our results indicate that anesthetics containing ketamine (ketamine/xylazine and ketamine/dexmedetomidine) significantly depress MCC, while combinations containing fentanyl (fentanyl/isoflurane, fentanyl/midazolam/dexmedetomidine) and propofol do not. Our method for assessing MCC is reproducible and has utility for studying the effects of other drug combinations.

scholarly journals Ophthalmic Drug Dosage Forms: Characterisation and Research Methods

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Przemysław Baranowski ◽  
Bożena Karolewicz ◽  
Maciej Gajda ◽  
Janusz Pluta
Keyword(s):  
Defense Mechanisms ◽  
Drug Application ◽  
Drug Dosage ◽  
Eye Drops ◽  
Eye Tissues ◽  
Ophthalmic Drug ◽  
Application Frequency

This paper describes hitherto developed drug forms for topical ocular administration, that is, eye drops, ointments,in situgels, inserts, multicompartment drug delivery systems, and ophthalmic drug forms with bioadhesive properties. Heretofore, many studies have demonstrated that new and more complex ophthalmic drug forms exhibit advantage over traditional ones and are able to increase the bioavailability of the active substance by, among others, reducing the susceptibility of drug forms to defense mechanisms of the human eye, extending contact time of drug with the cornea, increasing the penetration through the complex anatomical structure of the eye, and providing controlled release of drugs into the eye tissues, which allows reducing the drug application frequency. The rest of the paper describes recommendedin vitroandin vivostudies to be performed for various ophthalmic drugs forms in order to assess whether the form is acceptable from the perspective of desired properties and patient’s compliance.

Sign in / Sign up

Export Citation Format

Share Document