scholarly journals Parallelizable Microfluidic Platform to Model and Assess In Vitro Cellular Barriers: Technology and Application to Study the Interaction of 3D Tumor Spheroids with Cellular Barriers

Biosensors ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 314
Author(s):  
Arya Lekshmi Nair ◽  
Lena Mesch ◽  
Ingo Schulz ◽  
Holger Becker ◽  
Julia Raible ◽  
...  
Keyword(s):  
Mdck Cells ◽  
Impedance Measurement ◽  
Vital Role ◽  
Tumor Spheroids ◽  
Microfluidic Platform ◽  
Microinjection Molding ◽  
Unidirectional Flow ◽  
Flow Perfusion ◽  
And Function

Endothelial and epithelial cellular barriers play a vital role in the selective transport of solutes and other molecules. The properties and function of these barriers are often affected in case of inflammation and disease. Modelling cellular barriers in vitro can greatly facilitate studies of inflammation, disease mechanisms and progression, and in addition, can be exploited for drug screening and discovery. Here, we report on a parallelizable microfluidic platform in a multiwell plate format with ten independent cell culture chambers to support the modelling of cellular barriers co-cultured with 3D tumor spheroids. The microfluidic platform was fabricated by microinjection molding. Electrodes integrated into the chip in combination with a FT-impedance measurement system enabled transepithelial/transendothelial electrical resistance (TEER) measurements to rapidly assess real-time barrier tightness. The fluidic layout supports the tubeless and parallelized operation of up to ten distinct cultures under continuous unidirectional flow/perfusion. The capabilities of the system were demonstrated with a co-culture of 3D tumor spheroids and cellular barriers showing the growth and interaction of HT29 spheroids with a cellular barrier of MDCK cells.

scholarly journals Pseudogene ACTBP2 increases blood–brain barrier permeability by promoting KHDRBS2 transcription through recruitment of KMT2D/WDR5 in Aβ1–42 microenvironment

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Qianshuo Liu ◽  
Xiaobai Liu ◽  
Defeng Zhao ◽  
Xuelei Ruan ◽  
Rui Su ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Vital Role ◽  
Brain Barrier ◽  
Blood Brain ◽  
Bbb Permeability ◽  
Novel Target ◽  
And Function

AbstractThe blood–brain barrier (BBB) has a vital role in maintaining the homeostasis of the central nervous system (CNS). Changes in the structure and function of BBB can accelerate Alzheimer’s disease (AD) development. β-Amyloid (Aβ) deposition is the major pathological event of AD. We elucidated the function and possible molecular mechanisms of the effect of pseudogene ACTBP2 on the permeability of BBB in Aβ1–42 microenvironment. BBB model treated with Aβ1–42 for 48 h were used to simulate Aβ-mediated BBB dysfunction in AD. We proved that pseudogene ACTBP2, RNA-binding protein KHDRBS2, and transcription factor HEY2 are highly expressed in ECs that were obtained in a BBB model in vitro in Aβ1–42 microenvironment. In Aβ1–42-incubated ECs, ACTBP2 recruits methyltransferases KMT2D and WDR5, binds to KHDRBS2 promoter, and promotes KHDRBS2 transcription. The interaction of KHDRBS2 with the 3′UTR of HEY2 mRNA increases the stability of HEY2 and promotes its expression. HEY2 increases BBB permeability in Aβ1–42 microenvironment by transcriptionally inhibiting the expression of ZO-1, occludin, and claudin-5. We confirmed that knocking down of Khdrbs2 or Hey2 increased the expression levels of ZO-1, occludin, and claudin-5 in APP/PS1 mice brain microvessels. ACTBP2/KHDRBS2/HEY2 axis has a crucial role in the regulation of BBB permeability in Aβ1–42 microenvironment, which may provide a novel target for the therapy of AD.

Artery-on-a-chip platform for automated, multimodal assessment of cerebral blood vessel structure and function

Lab on a Chip ◽  
2015 ◽  
Vol 15 (12) ◽  
pp. 2660-2669 ◽  
Author(s):  
Sanjesh Yasotharan ◽  
Sascha Pinto ◽  
John G. Sled ◽  
Steffen-Sebastian Bolz ◽  
Axel Günther
Keyword(s):  
Blood Vessel ◽  
Blood Vessels ◽  
Structure And Function ◽  
Microfluidic Platform ◽  
Cerebral Blood Vessel ◽  
Multimodal Assessment ◽  
Vessel Structure ◽  
And Function

We present a compact microfluidic platform for the automated, multimodal assessment of intact small blood vesselsin vitro.

scholarly journals Colloidal lithography and current fabrication techniques producing in-plane nanotopography for biological applications

2006 ◽  
Vol 4 (12) ◽  
pp. 1-17 ◽  
Author(s):  
M.A Wood
Keyword(s):  
Low Cost ◽  
Control Cell ◽  
Three Dimensional ◽  
Vital Role ◽  
Material Surface ◽  
Colloidal Lithography ◽  
Substrate Topography ◽  
And Function

Substrate topography plays a vital role in cell and tissue structure and function in situ , where nanometric features, for example, the detail on single collagen fibrils, influence cell behaviour and resultant tissue formation. In vitro investigations demonstrate that nanotopography can be used to control cell reactions to a material surface, indicating its potential application in tissue engineering and implant fabrication. Developments in the catalyst, optical, medical and electronics industries have resulted in the production of nanopatterned surfaces using a variety of methods. The general protocols for nanomanufacturing require high resolution and low cost for fabricating devices. With respect to biological investigations, nanotopographies should occur across a large surface area (ensuring repeatability of experiments and patterning of implant surfaces), be reproducible (allowing for consistency in experiments), and preferably, accessible (limiting the requirement for specialist equipment). Colloidal lithography techniques fit these criteria, where nanoparticles can be utilized in combination with a functionalized substrate to produce in-plane nanotopographies. Subsequent lithographic processing of colloidal substrates utilizing, for example, reactive ion etching allows the production of modified colloidal-derived nanotopographies. In addition to two-dimensional in-plane nanofabrication, functionalized structures can be dip coated in colloidal sols, imparting nanotopographical cues to cells within a three-dimensional environment.

Mechanisms for establishing and reversing epithelial cell polarity

1989 ◽  
Vol 47 ◽  
pp. 802-803
Author(s):  
W. James Nelson ◽  
Allan Z. Wang
Keyword(s):  
Epithelial Cells ◽  
Cell Polarity ◽  
Plasma Membranes ◽  
Mdck Cells ◽  
Experimental Situation ◽  
Collagen Gel ◽  
Growth Conditions ◽  
Membrane Domain ◽  
And Function

Polarized epithelial cells play fundamental roles in the ontogeny and function of a variety of tissues and organs. However, the mechanisms involved in the morphogenesis of this important cell type are poorly understood. When epithelial cells, such as Madin-Darby Canine Kidney (MDCK) cells, are induced to develop polarity structurally and functionally different plasma membrane domains (apical and basal-lateral) must be established and maintained (ref. 1). This requires the sorting of constituent proteins to the correct membrane domain and the removal of incorrectly localized proteins. To understand how these domains are formed we designed an experimental situation in which cells that have established membrane polarity in one orientation are forced to reverse this orientation; by observing this reversal we should gain new insight into the mechanisms of membrane domain assembly and disassembly (Figure 1).We have now established this experimental situation in vitro. Under appropriate growth conditions in suspension culture or in a collagen gel MDCK cells are induced to form multicellular cysts. These multicellular cysts comprise a closed monolayer of cells of defined polarity (see below) that surrounds a fluid-filled lumen. We have begun to analyze morphologically the state of cell polarity of these structures using electron microscopy and immunocytochemistry with antibodies specific for marker proteins of the apical (gpl35) and basal-lateral (Na+,K+-ATPase) plasma membranes, and the tight junction (ZO-1) (Figure 2).

scholarly journals In vivo cartilage regeneration in a multi-layered articular cartilage architecture mimicking scaffold

2020 ◽  
Vol 9 (9) ◽  
pp. 601-612
Author(s):  
Karthikeyan Rajagopal ◽  
Sowmya Ramesh ◽  
Noel Malcolm Walter ◽  
Aditya Arora ◽  
Dhirendra S. Katti ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Cell Viability ◽  
Cartilage Regeneration ◽  
Fold Increase ◽  
Vital Role ◽  
Matrix Synthesis ◽  
Cartilage Formation ◽  
And Function

Aims Extracellular matrix (ECM) and its architecture have a vital role in articular cartilage (AC) structure and function. We hypothesized that a multi-layered chitosan-gelatin (CG) scaffold that resembles ECM, as well as native collagen architecture of AC, will achieve superior chondrogenesis and AC regeneration. We also compared its in vitro and in vivo outcomes with randomly aligned CG scaffold. Methods Rabbit bone marrow mesenchymal stem cells (MSCs) were differentiated into the chondrogenic lineage on scaffolds. Quality of in vitro regenerated cartilage was assessed by cell viability, growth, matrix synthesis, and differentiation. Bilateral osteochondral defects were created in 15 four-month-old male New Zealand white rabbits and segregated into three treatment groups with five in each. The groups were: 1) untreated and allogeneic chondrocytes; 2) multi-layered scaffold with and without cells; and 3) randomly aligned scaffold with and without cells. After four months of follow-up, the outcome was assessed using histology and immunostaining. Results In vitro testing showed that the secreted ECM oriented itself along the fibre in multi-layered scaffolds. Both types of CG scaffolds supported cell viability, growth, and matrix synthesis. In vitro chondrogenesis on scaffold showed an around 400-fold increase in collagen type 2 (COL2A1) expression in both CG scaffolds, but the total glycosaminoglycan (GAG)/DNA deposition was 1.39-fold higher in the multi-layered scaffold than the randomly aligned scaffold. In vivo cartilage formation occurred in both multi-layered and randomly aligned scaffolds treated with and without cells, and was shown to be of hyaline phenotype on immunostaining. The defects treated with multi-layered + cells, however, showed significantly thicker cartilage formation than the randomly aligned scaffold. Conclusion We demonstrated that MSCs loaded CG scaffold with multi-layered zonal architecture promoted superior hyaline AC regeneration. Cite this article: Bone Joint Res 2020;9(9):601–612.

Molecular architecture and functions of the neuronal cytoskeleton

1990 ◽  
Vol 48 (3) ◽  
pp. 2-3
Author(s):  
Nobutaka Hirokawa
Keyword(s):  
Major Elements ◽  
Molecular Structures ◽  
Organelle Transport ◽  
Molecular Architecture ◽  
Neuronal Morphogenesis ◽  
Microtubule Associated Proteins ◽  
Associated Proteins ◽  
And Function ◽  
Small Clusters

In this symposium I will present our studies about the molecular architecture and function of the cytomatrix of the nerve cells. The nerve cell is a highly polarized cell composed of highly branched dendrites, cell body, and a single long axon along the direction of the impulse propagation. Each part of the neuron takes characteristic shapes for which the cytoskeleton provides the framework. The neuronal cytoskeletons play important roles on neuronal morphogenesis, organelle transport and the synaptic transmission. In the axon neurofilaments (NF) form dense arrays, while microtubules (MT) are arranged as small clusters among the NFs. On the other hand, MTs are distributed uniformly, whereas NFs tend to run solitarily or form small fascicles in the dendrites Quick freeze deep etch electron microscopy revealed various kinds of strands among MTs, NFs and membranous organelles (MO). These structures form major elements of the cytomatrix in the neuron. To investigate molecular nature and function of these filaments first we studied molecular structures of microtubule associated proteins (MAP1A, MAP1B, MAP2, MAP2C and tau), and microtubules reconstituted from MAPs and tubulin in vitro. These MAPs were all fibrous molecules with different length and formed arm like projections from the microtubule surface.

Role of the 807 C/T Polymorphism of the α2 Gene in Platelet GP Ia Collagen Receptor Expression and Function

1999 ◽  
Vol 81 (06) ◽  
pp. 951-956 ◽  
Author(s):  
J. Corral ◽  
R. González-Conejero ◽  
J. Rivera ◽  
F. Ortuño ◽  
P. Aparicio ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Cell Types ◽  
Receptor Expression ◽  
Case Control Studies ◽  
Platelet Surface ◽  
Vitro Analysis ◽  
And Function ◽  
In Vitro Analysis

SummaryThe variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of this polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a significant association between the 807 C/T polymorphism and the platelet GP Ia density. The T allele correlated with high number of GP Ia molecules on platelet surface. In addition, we observed a similar association of this polymorphism with the expression of this protein in other blood cell types. The platelet responsiveness to collagen was determined by “in vitro” analysis of the platelet activation and aggregation response. We found no significant differences in these functional platelet parameters according to the 807 C/T genotype. Finally, results from 3 case/control studies involving 302 consecutive patients (101 with coronary heart disease, 104 with cerebrovascular disease and 97 with deep venous thrombosis) determined that the 807 C/T polymorphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.

Type I Interferons promote maintenance and function of follicular T helper cells in vitro

2019 ◽  
Author(s):  
S Ehrlich ◽  
K Wild ◽  
M Smits ◽  
K Zoldan ◽  
M Hofmann ◽  
...  
Keyword(s):  
T Helper Cells ◽  
Type I Interferons ◽  
Type I ◽  
T Helper ◽  
Helper Cells ◽  
Follicular T Helper Cells ◽  
And Function
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