scholarly journals Cerebral organoids at the air-liquid interface generate diverse nerve tracts with functional output

2018 ◽  
Author(s):  
Stefano L. Giandomenico ◽  
Susanna B. Mierau ◽  
George M. Gibbons ◽  
Lea M.D. Wenger ◽  
Laura Masullo ◽  
...  

Three-dimensional neural organoids are emerging tools with the potential for improving our understanding of human brain development and neurological disorders. Recent advances in this field have demonstrated their capacity to model neurogenesis1,2, neuronal migration and positioning3,4, and even response to sensory input5. However, it remains to be seen whether these tissues can model axon guidance dynamics and the formation of complex connectivity with functional neuronal output. Here, we have established a longterm air-liquid interface culture paradigm that leads to improved neuronal survival and allows for imaging of axon guidance. Over time, these cultures spontaneously form thick axon tracts capable of projecting over long distances. Axon bundles display various morphological behaviors including intracortical projection within and across the organoid, growth cone turning, decussation, and projection away from the organoid. Single-cell RNA-sequencing reveals the full repertoire of cortical neuronal identities, and retrograde labelling demonstrates these tract morphologies match the appropriate molecular identities, namely callosal and corticofugal neuron types. We show that these neurons are functionally mature, generate active networks within the organoid, and that extracortical projecting tracts innervate and activate mouse spinal cord-muscle explants. Muscle contractions can be evoked by stimulation of the organoid, while axotomy of the innervating tracts abolishes the muscle contraction response, demonstrating dependence on connection with the organoid. Overall, these results reveal a remarkable selforganization of corticofugal and callosal tracts with a functional output, providing new opportunities to examine relevant aspects of human CNS development and response to injury.

2019 ◽  
Vol 22 (4) ◽  
pp. 669-679 ◽  
Author(s):  
Stefano L. Giandomenico ◽  
Susanna B. Mierau ◽  
George M. Gibbons ◽  
Lea M. D. Wenger ◽  
Laura Masullo ◽  
...  

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2784
Author(s):  
Mh Busra Fauzi ◽  
Zahra Rashidbenam ◽  
Aminuddin Bin Saim ◽  
Ruszymah Binti Hj Idrus

Three-dimensional (3D) in vitro skin models have been widely used for cosmeceutical and pharmaceutical applications aiming to reduce animal use in experiment. This study investigate capability of ovine tendon collagen type I (OTC-I) sponge suitable platform for a 3D in vitro skin model using co-cultured skin cells (CC) containing human epidermal keratinocytes (HEK) and human dermal fibroblasts (HDF) under submerged (SM) and air-liquid interface (ALI) conditions. Briefly, the extracted OTC-I was freeze-dried and crosslinked with genipin (OTC-I_GNP) and carbodiimide (OTC-I_EDC). The gross appearance, physico-chemical characteristics, biocompatibility and growth profile of seeded skin cells were assessed. The light brown and white appearance for the OTC-I_GNP scaffold and other groups were observed, respectively. The OTC-I_GNP scaffold demonstrated the highest swelling ratio (~1885%) and water uptake (94.96 ± 0.14%). The Fourier transformation infrared demonstrated amide A, B and I, II and III which represent collagen type I. The microstructure of all fabricated sponges presented a similar surface roughness with the presence of visible collagen fibers and a heterogenous porous structure. The OTC-I_EDC scaffold was more toxic and showed the lowest cell attachment and proliferation as compared to other groups. The micrographic evaluation revealed that CC potentially formed the epidermal- and dermal-like layers in both SM and ALI that prominently observed with OTC-I_GNP compared to others. In conclusion, these results suggest that OTC_GNP could be used as a 3D in vitro skin model under ALI microenvironment.


2019 ◽  
Vol 201 (18) ◽  
Author(s):  
Aretha Fiebig

ABSTRACTIn aquatic environments,Caulobacterspp. can be found at the boundary between liquid and air known as the neuston. I report an approach to study temporal features ofCaulobacter crescentuscolonization and pellicle biofilm development at the air-liquid interface and have defined the role of cell surface structures in this process. At this interface,C. crescentusinitially forms a monolayer of cells bearing a surface adhesin known as the holdfast. When excised from the liquid surface, this monolayer strongly adheres to glass. The monolayer subsequently develops into a three-dimensional structure that is highly enriched in clusters of stalked cells known as rosettes. As this pellicle film matures, it becomes more cohesive and less adherent to a glass surface. A mutant strain lacking a flagellum does not efficiently reach the surface, and strains lacking type IV pili exhibit defects in organization of the three-dimensional pellicle. Strains unable to synthesize the holdfast fail to accumulate at the boundary between air and liquid and do not form a pellicle. Phase-contrast images support a model whereby the holdfast functions to trapC. crescentuscells at the air-liquid boundary. Unlike the holdfast, neither the flagellum nor type IV pili are required forC. crescentusto partition to the air-liquid interface. While it is well established that the holdfast enables adherence to solid surfaces, this study provides evidence that the holdfast has physicochemical properties that allow partitioning of nonmotile mother cells to the air-liquid interface and facilitate colonization of this microenvironment.IMPORTANCEIn aquatic environments, the boundary at the air interface is often highly enriched with nutrients and oxygen. Colonization of this niche likely confers a significant fitness advantage in many cases. This study provides evidence that the cell surface adhesin known as a holdfast enablesCaulobacter crescentusto partition to and colonize the air-liquid interface. Additional surface structures, including the flagellum and type IV pili, are important determinants of colonization and biofilm formation at this boundary. Considering that holdfast-like adhesins are broadly conserved inCaulobacterspp. and other members of the diverse classAlphaproteobacteria, these surface structures may function broadly to facilitate colonization of air-liquid boundaries in a range of ecological contexts, including freshwater, marine, and soil ecosystems.


2005 ◽  
Vol 49 (11) ◽  
pp. 4671-4680 ◽  
Author(s):  
Graciela Andrei ◽  
Joost van den Oord ◽  
Pierre Fiten ◽  
Ghislain Opdenakker ◽  
Chris De Wolf-Peeters ◽  
...  

ABSTRACT The course of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) and varicella-zoster virus (VZV) infections in squamous epithelial cells cultured in a three-dimensional organotypic raft culture was tested. In these raft cultures, normal human keratinocytes isolated from neonatal foreskins grown at the air-liquid interface stratified and differentiated, reproducing a fully differentiated epithelium. Typical cytopathic changes identical to those found in the squamous epithelium in vivo, including ballooning and reticular degeneration with the formation of multinucleate cells, were observed throughout the raft following infection with HSV and VZV at different times after lifting the cultures to the air-liquid interface. For VZV, the aspects of the lesions depended on the stage of differentiation of the organotypic cultures. The activity of reference antiviral agents, acyclovir (ACV), penciclovir (PCV), brivudin (BVDU), foscarnet (PFA), and cidofovir (CDV), was evaluated against wild-type and thymidine kinase (TK) mutants of HSV and VZV in the raft cultures. ACV, PCV, and BVDU protected the epithelium against cytopathic effect induced by wild-type viruses in a concentration-dependent manner, while treatment with CDV and PFA proved protective against the cytodestructive effects induced by both TK+ and TK− strains. The quantification of the antiviral effects in the rafts were accomplished by measuring viral titers by plaque assay for HSV and by measuring viral DNA load by real-time PCR for VZV. A correlation between the degree of protection as determined by histological examination and viral quantification could be demonstrated The three-dimensional epithelial raft culture represents a novel model for the study of antiviral agents active against HSV and VZV. Since no animal model is available for the evaluation of antiviral agents against VZV, the organotypic cultures may be considered a model to evaluate the efficacy of new anti-VZV antivirals before clinical trials.


2019 ◽  
Author(s):  
Aretha Fiebig

AbstractIn aquatic environments,Caulobacterspp. are often present at the boundary between liquid and air known as the neuston. I report an approach to study temporal features ofCaulobacter crescentuscolonization and pellicle biofilm development at the air-liquid interface, and have defined the role of cell surface structures in this process. At this interface,C. crescentusinitially forms a monolayer of cells bearing a surface adhesin known as the holdfast. When excised from the liquid surface, this monolayer strongly adheres to glass. The monolayer subsequently develops into a three-dimensional structure that is highly enriched in clusters of stalked cells known as rosettes. As this pellicle film matures, it becomes more cohesive and less adherent to a glass surface. A mutant strain lacking a flagellum does not efficiently reach the surface, and strains lacking type IV pili exhibit defects in organization of the three-dimensional pellicle. Strains unable to synthesize holdfast fail to accumulate at the boundary between air and liquid and do not form a pellicle. Phase contrast images support a model whereby the holdfast functions to trapC. crescentuscells at the air-liquid boundary. Unlike the holdfast, neither the flagellum nor type IV pili are required forC. crescentusto partition to the air-liquid interface. While it is well established that the holdfast enables adherence to solid surfaces, this study provides evidence that the holdfast has physicochemical properties required for partitioning of non-motile mother cells to the air-liquid interface, which facilitates colonization of this microenvironment.ImportanceIn aquatic environments the boundary at the air interface is often highly enriched with nutrients and oxygen. Colonization of this niche likely confers a significant fitness advantage in many cases. This study provides evidence that the cell surface adhesin known as a holdfast enablesCaulobacter crescentusto partition to and colonize the air-liquid interface. Additional surface structures including the flagellum and type IV pili are important determinants of colonization and biofilm formation at this boundary. Considering that holdfast-like adhesins are broadly conserved inCaulobacterspp. and other members of the diverse classAlphaproteobacteria, these surface structures may function broadly to facilitate colonization of air-liquid boundaries in a range of ecological contexts including freshwater, marine, and soil ecosystems.


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