Microtubule-dependent subcellular organisation of pluripotent cells

Development ◽  
2021 ◽  
Vol 148 (20) ◽  
Author(s):  
Azelle Hawdon ◽  
Asma Aberkane ◽  
Jennifer Zenker
Keyword(s):  
Pluripotent Stem Cells ◽  
Cell Structure ◽  
Structure And Function ◽  
Pluripotent Cells ◽  
Differentiated Cells ◽  
Intracellular Movement ◽  
And Function

ABSTRACT With the advancement of cutting-edge live imaging technologies, microtubule remodelling has evolved as an integral regulator for the establishment of distinct differentiated cells. However, despite their fundamental role in cell structure and function, microtubules have received less attention when unravelling the regulatory circuitry of pluripotency. Here, we summarise the role of microtubule organisation and microtubule-dependent events required for the formation of pluripotent cells in vivo by deciphering the process of early embryogenesis: from fertilisation to blastocyst. Furthermore, we highlight current advances in elucidating the significance of specific microtubule arrays in in vitro culture systems of pluripotent stem cells and how the microtubule cytoskeleton serves as a highway for the precise intracellular movement of organelles. This Review provides an informed understanding of the intrinsic role of subcellular architecture of pluripotent cells and accentuates their regenerative potential in combination with innovative light-inducible microtubule techniques.

scholarly journals The Role of the 3Rs for Understanding and Modeling the Human Placenta

2021 ◽  
Vol 10 (15) ◽  
pp. 3444
Author(s):  
Joana Costa ◽  
Ruth Mackay ◽  
Sophie-Christine de Aguiar Greca ◽  
Alessandro Corti ◽  
Elisabete Silva ◽  
...  
Keyword(s):  
Human Placenta ◽  
Ex Vivo ◽  
Structure And Function ◽  
Collective Impact ◽  
And Function ◽  
Animal Welfare Legislation ◽  
Made In

Modeling the physiology of the human placenta is still a challenge, despite the great number of scientific advancements made in the field. Animal models cannot fully replicate the structure and function of the human placenta and pose ethical and financial hurdles. In addition, increasingly stricter animal welfare legislation worldwide is incentivizing the use of 3R (reduction, refinement, replacement) practices. What efforts have been made to develop alternative models for the placenta so far? How effective are they? How can we improve them to make them more predictive of human pathophysiology? To address these questions, this review aims at presenting and discussing the current models used to study phenomena at the placenta level: in vivo, ex vivo, in vitro and in silico. We describe the main achievements and opportunities for improvement of each type of model and critically assess their individual and collective impact on the pursuit of predictive studies of the placenta in line with the 3Rs and European legislation.

scholarly journals Multiplatform Physiologic and Metabolic Phenotyping Reveals Microbial Toxicity

mSystems ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Jingwei Cai ◽  
Robert G. Nichols ◽  
Imhoi Koo ◽  
Zachary A. Kalikow ◽  
Limin Zhang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Flow Cytometry ◽  
Free Radical ◽  
Gut Microbiota ◽  
Structure And Function ◽  
Metabolic Phenotyping ◽  
And Function

ABSTRACTThe gut microbiota is susceptible to modulation by environmental stimuli and therefore can serve as a biological sensor. Recent evidence suggests that xenobiotics can disrupt the interaction between the microbiota and host. Here, we describe an approach that combinesin vitromicrobial incubation (isolated cecal contents from mice), flow cytometry, and mass spectrometry- and1H nuclear magnetic resonance (NMR)-based metabolomics to evaluate xenobiotic-induced microbial toxicity. Tempol, a stabilized free radical scavenger known to remodel the microbial community structure and functionin vivo, was studied to assess its direct effect on the gut microbiota. The microbiota was isolated from mouse cecum and was exposed to tempol for 4 h under strict anaerobic conditions. The flow cytometry data suggested that short-term tempol exposure to the microbiota is associated with disrupted membrane physiology as well as compromised metabolic activity. Mass spectrometry and NMR metabolomics revealed that tempol exposure significantly disrupted microbial metabolic activity, specifically indicated by changes in short-chain fatty acids, branched-chain amino acids, amino acids, nucleotides, glucose, and oligosaccharides. In addition, a mouse study with tempol (5 days gavage) showed similar microbial physiologic and metabolic changes, indicating that thein vitroapproach reflectedin vivoconditions. Our results, through evaluation of microbial viability, physiology, and metabolism and a comparison ofin vitroandin vivoexposures with tempol, suggest that physiologic and metabolic phenotyping can provide unique insight into gut microbiota toxicity.IMPORTANCEThe gut microbiota is modulated physiologically, compositionally, and metabolically by xenobiotics, potentially causing metabolic consequences to the host. We recently reported that tempol, a stabilized free radical nitroxide, can exert beneficial effects on the host through modulation of the microbiome community structure and function. Here, we investigated a multiplatform phenotyping approach that combines high-throughput global metabolomics with flow cytometry to evaluate the direct effect of tempol on the microbiota. This approach may be useful in deciphering how other xenobiotics directly influence the microbiota.

The extracellular matrix of the developing cornea: diversity, deposition and function*

Development ◽  
1988 ◽  
Vol 103 (Supplement) ◽  
pp. 195-205
Author(s):  
J. B. L. Bard ◽  
M. K. Bansal ◽  
A. S. A. Ross
Keyword(s):  
Extracellular Matrix ◽  
Chondroitin Sulphate ◽  
Corneal Stroma ◽  
Experimental System ◽  
Collagen I ◽  
And Function ◽  
20 Nm

This paper examines the role of the extracellular matrix (ECM) in the development of the cornea. After a brief summary of the corneal structure and ECM, we describe evidence suggesting that the differentiation of neural crest (NC) cells into endothelium and fibroblasts is under the control of ocular ECM. We then examine the role of collagen I in stromal morphogenesis by comparing normal corneas with those of homozygous Movl3 mice which do not make collagen I. We report that, in spite of this absence, the cellular morphology of the Movl3 eye is indistinguishable from that of the wild type. In the 16-day mutant stroma, however, the remaining collagens form small amounts of disorganized, thin fibrils rather than orthogonally organized 20 nm-diameter fibrils; a result implying that collagen I plays only a structural role and that its absence is not compensated for. It also suggests that, because these remaining collagens will not form the normal fibrils that they will in vitro, fibrillogenesis in the corneal stroma differs from that elsewhere. The latter part of the paper describes our current work on chick stromal deposition using corneal epithelia isolated with an intact basal lamina that lay down in vitro ∼3μm-thick stromas of organized fibrils similar to that seen in vivo. This experimental system has yielded two unexpected results. First, the amount of collagen and proteoglycans produced by such epithelia is not dependent on whether its substratum is collagenous and we therefore conclude that stromal production by the intact epithelium is more autonomous than hitherto thought. Second, chondroitin sulphate (CS), the predominant proteoglycan, appears to play no role in stromal morphogenesis: epithelia cultured in testicular hyaluronidase, which degrades CS, lay down stromas whose organization and fibrildiameter distribution are indistinguishable from controls. One possible role for CS, however, is as a lubricant which facilitates corneal growth: it could allow fibrils to move over one another without deforming their orthogonal organization. Finally, we have examined the processes of fibrillogenesis in the corneal stroma and conclude that they are different from those elsewhere in the embryo and in vitro, perhaps because there is in the primary stroma an unidentified, highly hydrated ECM macromolecule that embeds the fibrils and that may mediate their morphogenesis.

scholarly journals Characterization and function of Ca2+-activated K+ channels in arteriolar muscle cells

1998 ◽  
Vol 274 (1) ◽  
pp. H27-H34 ◽  
Author(s):  
William F. Jackson ◽  
Kevin L. Blair
Keyword(s):  
Single Channel ◽  
Muscle Cells ◽  
Hill Coefficient ◽  
Apparent Lack ◽  
Maximal Activation ◽  
And Function ◽  
Resting Tone

We examined the functional role of large-conductance Ca2+-activated K+(KCa) channels in the hamster cremasteric microcirculation by intravital videomicroscopy and characterized the single-channel properties of these channels in inside-out patches of membrane from enzymatically isolated cremasteric arteriolar muscle cells. In second-order (39 ± 1 μm, n = 8) and third-order (19 ± 2 μm, n = 8) cremasteric arterioles with substantial resting tone, superfusion with the KCa channel antagonists tetraethylammonium (TEA, 1 mM) or iberiotoxin (IBTX, 100 nM) had no significant effect on resting diameters ( P > 0.05). However, TEA potentiated O2-induced arteriolar constriction in vivo, and IBTX enhanced norepinephrine-induced contraction of cremasteric arteriolar muscle cells in vitro. Patch-clamp studies revealed unitary K+-selective and IBTX-sensitive currents with a single-channel conductance of 240 ± 2 pS between −60 and 60 mV ( n = 7 patches) in a symmetrical 140 mM K+ gradient. The free Ca2+ concentration ([Ca2+]) for half-maximal channel activation was 44 ± 3, 20 ± 1, 6 ± 0.4, and 3 ± 0.5 μM at membrane potentials of −60, −30, +30, and +60 mV, respectively ( n = 5), with a Hill coefficient of 1.9 ± 0.2. Channel activity increased e-fold for a 16 ± 1 mV ( n = 6) depolarization. The plot of log[Ca2+] vs. voltage for half-maximal activation ( V ½) was linear ( r 2 = 0.9843, n = 6); the change in V ½ for a 10-fold change in [Ca2+] was 84 ± 5 mV, and the [Ca2+] for half-maximal activation at 0 mV (Ca0; the Ca2+ set point) was 9 μM. Thus, in vivo, KCa channels are silent in cremasteric arterioles at rest but can be recruited during vasoconstriction. We propose that the high Ca0 is responsible for the apparent lack of activity of these channels in resting cremasteric arterioles, and we suggest that this may result from expression of unique KCa channels in the microcirculation.

The Role of the Islet Niche on Beta Cell Structure and Function

2020 ◽  
Vol 432 (5) ◽  
pp. 1407-1418 ◽  
Author(s):  
Eckhard Lammert ◽  
Peter Thorn
Keyword(s):  
Beta Cell ◽  
Cell Structure ◽  
Structure And Function ◽  
And Function

scholarly journals Effect of lycorine on the structure and function of hepatoma cell membrane in vitro and in vivo

2020 ◽  
Vol 34 (1) ◽  
pp. 104-114 ◽  
Author(s):  
Guosong Xin ◽  
Miao Yu ◽  
Yang Hu ◽  
Shiyong Gao ◽  
Zheng Qi ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Hepatoma Cell ◽  
Structure And Function ◽  
And Function

PSGL-1 regulates platelet P-selectin-mediated endothelial activation and shedding of P-selectin from activated platelets

2007 ◽  
Vol 98 (10) ◽  
pp. 806-812 ◽  
Author(s):  
Vandana Dole ◽  
Wolfgang Bergmeier ◽  
Ian Patten ◽  
Junichi Hirahashi ◽  
Tanya Mayadas ◽  
...  
Keyword(s):  
Endothelial Activation ◽  
Leukocyte Rolling ◽  
Wild Type ◽  
Platelet Surface ◽  
Activated Platelets ◽  
And Function ◽  
Body Secretion

SummaryWe have previously shown that activated platelets in circulation stimulate release of endothelial Weibel-Palade bodies thus increasing leukocyte rolling in venules. P-selectin on the activated platelets mediates adhesion to leukocytes via PSGL-1 and is rapidly shed into plasma. We were interested in studying the role of PSGL-1 in regulating expression and function of platelet P-selectin. We show here that PSGL-1 is critical for the activation of endothelial cells in venules of mice infused with activated platelets. The interaction of platelet P-selectin with PSGL-1 is also required for P-selectin shedding, as P-selectin was retained significantly longer on the surface of activated platelets infused into PSGL-1-/- compared to wild-type mice. The leukocyte integrin αMβ2 (Mac-1) was not required for P-selectin shedding. In addition to shedding, P-selectin can be downregulated from the platelet surface through internalization and this is the predominant mechanism in the absence of PSGL-1. We demonstrate that leukocyte- neutrophil elastase,known to cleave P-selectin in vitro, is not the major sheddase for P-selectin in vivo. In conclusion, interaction of platelet P-selectin with PSGL-1 is crucial for activation of the endothelium andWeibel-Palade body secretion. The interaction with PSGL-1 also results in rapid shedding of P-selectin thus downregulating the inflammatory potential of the platelet.

Hemodynamic Shear Stress And Endothelial Cell Function: In Vitro Studies

1981 ◽  
Author(s):  
M A Gimbrone ◽  
C F Dewey ◽  
P F Davies ◽  
S R Bussolari
Keyword(s):  
Shear Stress ◽  
Endothelial Cell ◽  
Fluid Shear Stress ◽  
Cell Structure ◽  
Structure And Function ◽  
Cellular Migration ◽  
Shear Stresses ◽  
Endothelial Cell Function ◽  
And Function

The vascular endothelial lining in vivo is constantly subjected to hemodynamic shear stresses resulting from normal and altered patterns of blood flow. To facilitate the study of effects of fluid shear stress on endothelial cell structure and function, we have developed an in vitro system, utilizing a cone-plate apparatus, to subject coverslip cultures of bovine aortic endothelial cells (BAEC) to controlled levels of shear (up to 102 dynes/cm2) in either laminar or turbulent flow. The magnitude and direction of shear stress within the system are accurately known from both theory and experimental measurements. The data reported here are for laminar flow. Subconfluent BAEC cultures continuously exposed to 1-5 dynes/cm2 shear proliferated at a rate comparable to that of static cultures, and postconfluent monolayers appeared unaltered morphologically for up to 1 week. In contrast, BAEC cultures (both postconfluent and subconfluent) exposed to 8 dynes/cm2 developed dramatic, time-dependent morphological changes. By 48 hrs, cells uniformly assumed an ellipsoidal configuration, with their major axes aligned in the direction of flow. Exposure to >10 dynes/cm2 caused variable cell detachment from plain glass substrates. Cellular migration into linear “wounds”, created in confluent areas, was influenced by both the direction and amplitude of applied shear. Exposure to 8 dynes/ cm2 induced functional alterations, including increased fluid (bulk phase) endocytosis, prostaglandin production and platelet reactivity. These observations indicate that fluid mechanical forces can directly influence endothelial cell structure and function. Hemodynamic modulation of endothelial cell behavior may be relevant to normal vessel wall physiology, as well as the pathogenesis of atherosclerosis and thrombosis.

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