scholarly journals Anisotropic expansion of hepatocyte lumina enforced by apical bulkheads

2021 ◽  
Vol 220 (10) ◽  
Author(s):  
Lenka Belicova ◽  
Urska Repnik ◽  
Julien Delpierre ◽  
Elzbieta Gralinska ◽  
Sarah Seifert ◽  
...  
Keyword(s):  
Liver Tissue ◽  
Cyst Formation ◽  
Apical Surface ◽  
Adult Liver ◽  
3D Network ◽  
Anisotropic Expansion ◽  
Tubular Lumen ◽  
Hepatocyte Polarity ◽  
Mechanical Elements

Lumen morphogenesis results from the interplay between molecular pathways and mechanical forces. In several organs, epithelial cells share their apical surfaces to form a tubular lumen. In the liver, however, hepatocytes share the apical surface only between adjacent cells and form narrow lumina that grow anisotropically, generating a 3D network of bile canaliculi (BC). Here, by studying lumenogenesis in differentiating mouse hepatoblasts in vitro, we discovered that adjacent hepatocytes assemble a pattern of specific extensions of the apical membrane traversing the lumen and ensuring its anisotropic expansion. These previously unrecognized structures form a pattern, reminiscent of the bulkheads of boats, also present in the developing and adult liver. Silencing of Rab35 resulted in loss of apical bulkheads and lumen anisotropy, leading to cyst formation. Strikingly, we could reengineer hepatocyte polarity in embryonic liver tissue, converting BC into epithelial tubes. Our results suggest that apical bulkheads are cell-intrinsic anisotropic mechanical elements that determine the elongation of BC during liver tissue morphogenesis.

scholarly journals 3D Culture System for Liver Tissue Mimicking Hepatic Plates for Improvement of Human Hepatocyte (C3A) Function and Polarity

2020 ◽  
Vol 2020 ◽  
pp. 1-22 ◽  
Author(s):  
Zhidong Jia ◽  
Yuan Cheng ◽  
Xinan Jiang ◽  
Chengyan Zhang ◽  
Gaoshang Wang ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Liver Tissue ◽  
3D Culture ◽  
Basic Unit ◽  
3D Cultures ◽  
Liver Tissue Engineering ◽  
Chip Technology ◽  
Hepatocyte Polarity ◽  
Liver Tissues

In vitro 3D hepatocyte culture constitutes a core aspect of liver tissue engineering. However, conventional 3D cultures are unable to maintain hepatocyte polarity, functional phenotype, or viability. Here, we employed microfluidic chip technology combined with natural alginate hydrogels to construct 3D liver tissues mimicking hepatic plates. We comprehensively evaluated cultured hepatocyte viability, function, and polarity. Transcriptome sequencing was used to analyze changes in hepatocyte polarity pathways. The data indicate that, as culture duration increases, the viability, function, polarity, mRNA expression, and ultrastructure of the hepatic plate mimetic 3D hepatocytes are enhanced. Furthermore, hepatic plate mimetic 3D cultures can promote changes in the bile secretion pathway via effector mechanisms associated with nuclear receptors, bile uptake, and efflux transporters. This study provides a scientific basis and strong evidence for the physiological structures of bionic livers prepared using 3D cultures. The systems and cultured liver tissues described here may serve as a better in vitro 3D culture platform and basic unit for varied applications, including drug development, hepatocyte polarity research, bioartificial liver bioreactor design, and tissue and organ construction for liver tissue engineering or cholestatic liver injury.

Ultrastructural autoradiography of L6 skeletal-muscle cells exposed to a tritiated macrolide antibiotic (LY237216) in vitro

1992 ◽  
Vol 50 (1) ◽  
pp. 612-613
Author(s):  
S.L. White ◽  
C.B. Jensen ◽  
D.D. Giera ◽  
D.A. Laska ◽  
M.N. Novilla ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Quantitative Analysis ◽  
Macrolide Antibiotic ◽  
Circle Method ◽  
Apical Surface ◽  
Polycarbonate Membrane ◽  
L6 Cells ◽  
Low Viscosity ◽  
Erythromycin A

In vitro exposure to LY237216 (9-Deoxo-11-deoxy-9,11-{imino[2-(2-methoxyethoxy)ethylidene]-oxy}-(9S)-erythromycin), a macrolide antibiotic, was found to induce cytoplasmic vacuolation in L6 skeletal muscle myoblast cultures (White, S.L., unpubl). The present study was done to determine, by autoradiographic quantitative analysis, the subcellular distribution of 3H-LY237216 in L6 cells.L6 cells (ATCC, CRL 1458) were cultured to confluency on polycarbonate membrane filters (Millipore Corp., Bedford, MA) in M-199 medium (GIBCO® Labs) with 10% fetal bovine serum. The cells were exposed from the apical surface for 1-hour to unlabelled-compound (0 μCi/ml) or 50 (μCi/ml of 3H-LY237216 at a compound concentration of 0.25 mg/ml. Following a rapid rinse in compound-free growth medium, the cells were slam-frozen against a liquid nitrogen cooled, polished copper block in a CF-100 cryofixation unit (LifeCell Corp., The Woodlands, TX). Specimens were dried in the MDD-C Molecular Distillation Drier (LifeCell Corp.), vapor osmicated and embedded in Spurrs low viscosity resin. Ultrathin sections collected on formvar coated stainless steel grids were counter-stained, then individually mounted on corks. A monolayer of Ilford L4 nuclear emulsion (Polysciences, Inc., Warrington, PA) was placed on the sections, utilizing a modified “loop method”. The emulsions were exposed for 7-weeks in a light-tight box at 4°C. Autoradiographs were developed in Microdol-X developer and examined on a Philips EM410LS transmission electron microscope. Quantitative analysis of compound localization employed the point and circle approach of Williams; incorporating the probability circle method of Salpeter and McHenry.

Perturbation of Platelet Adhesion to Endothelial Cells by Plasminogen Activation In Vitro

1997 ◽  
Vol 78 (02) ◽  
pp. 934-938 ◽  
Author(s):  
Hsiun-ing Chen ◽  
Yueh-I Wu ◽  
Yu-Lun Hsieh ◽  
Guey-Yueh Shi ◽  
Meei-Jyh Jiang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Platelet Adhesion ◽  
Treatment Time ◽  
Shape Change ◽  
Umbilical Vein ◽  
Tissue Type ◽  
Apical Surface ◽  
Plasminogen Activation

SummaryTo investigate whether the endothelium-platelet interactions may be altered by plasminogen activation, cultured human umbilical vein endothelial cells (ECs) were treated with tissue-type plasminogen activator (t-PA) in the presence of plasminogen, and platelet adhesion to ECs was subsequently measured by using a tapered flow chamber. Our results demonstrated that platelets adhered more readily to t-PA treated EC monolayer than to the control monolayer at all shear stress levels tested. This phenomenon was treatment time-dependent and dose-dependent, and it could be blocked by adding plasmin inhibitors, such as e-amino caproic acid and aprotinin. Adherent platelets on t-PA treated EC monolayer underwent more severe shape change than those on the control monolayer. While the extracellular matrix directly treated with t-PA attracted less platelets than the control matrix did, platelet adhesion to the matrix that was produced by t-PA-treated ECs was unaltered. These data suggest that t-PA treatment on ECs compromised antiplatelet-adhesion capability on their apical surface without altering the reactivity of their extracellular matrix towards platelets.

scholarly journals Lithium-Doped Biological-Derived Hydroxyapatite Coatings Sustain In Vitro Differentiation of Human Primary Mesenchymal Stem Cells to Osteoblasts

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 781 ◽  
Author(s):  
Paula E. Florian ◽  
Liviu Duta ◽  
Valentina Grumezescu ◽  
Gianina Popescu-Pelin ◽  
Andrei C. Popescu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Doping Agent ◽  
Hydroxyapatite Coatings ◽  
3D Network ◽  
Immunofluorescence Labelling ◽  
Good Biocompatibility ◽  
Adhesion Process

This study is focused on the adhesion and differentiation of the human primary mesenchymal stem cells (hMSC) to osteoblasts lineage on biological-derived hydroxyapatite (BHA) and lithium-doped BHA (BHA:LiP) coatings synthesized by Pulsed Laser Deposition. An optimum adhesion of the cells on the surface of BHA:LiP coatings compared to control (uncoated Ti) was demonstrated using immunofluorescence labelling of actin and vinculin, two proteins involved in the initiation of the cell adhesion process. BHA:LiP coatings were also found to favor the differentiation of the hMSC towards an osteoblastic phenotype in the presence of osteoinductive medium, as revealed by the evaluation of osteoblast-specific markers, osteocalcin and alkaline phosphatase. Numerous nodules of mineralization secreted from osteoblast cells grown on the surface of BHA:LiP coatings and a 3D network-like organization of cells interconnected into the extracellular matrix were evidenced. These findings highlight the good biocompatibility of the BHA coatings and demonstrate that the use of lithium as a doping agent results in an enhanced osteointegration potential of the synthesized biomaterials, which might therefore represent viable candidates for future in vivo applications.

scholarly journals Investigation of Wall Shear Stress in Cardiovascular Research and in Clinical Practice—From Bench to Bedside

2021 ◽  
Vol 22 (11) ◽  
pp. 5635
Author(s):  
Katharina Urschel ◽  
Miyuki Tauchi ◽  
Stephan Achenbach ◽  
Barbara Dietel
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Cell Function ◽  
Computational Techniques ◽  
Apical Surface ◽  
Cardiovascular Research ◽  
Endothelial Cell Function ◽  
Wall Shear

In the 1900s, researchers established animal models experimentally to induce atherosclerosis by feeding them with a cholesterol-rich diet. It is now accepted that high circulating cholesterol is one of the main causes of atherosclerosis; however, plaque localization cannot be explained solely by hyperlipidemia. A tremendous amount of studies has demonstrated that hemodynamic forces modify endothelial athero-susceptibility phenotypes. Endothelial cells possess mechanosensors on the apical surface to detect a blood stream-induced force on the vessel wall, known as “wall shear stress (WSS)”, and induce cellular and molecular responses. Investigations to elucidate the mechanisms of this process are on-going: on the one hand, hemodynamics in complex vessel systems have been described in detail, owing to the recent progress in imaging and computational techniques. On the other hand, investigations using unique in vitro chamber systems with various flow applications have enhanced the understanding of WSS-induced changes in endothelial cell function and the involvement of the glycocalyx, the apical surface layer of endothelial cells, in this process. In the clinical setting, attempts have been made to measure WSS and/or glycocalyx degradation non-invasively, for the purpose of their diagnostic utilization. An increasing body of evidence shows that WSS, as well as serum glycocalyx components, can serve as a predicting factor for atherosclerosis development and, most importantly, for the rupture of plaques in patients with high risk of coronary heart disease.

scholarly journals Proteomic profiling of murine biliary-derived hepatic organoids and their capacity for drug disposition, bioactivation and detoxification

2021 ◽  
Author(s):  
Lawrence Howell ◽  
Rosalind E. Jenkins ◽  
Stephen Lynch ◽  
Carrie Duckworth ◽  
B. Kevin Park ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Drug Metabolism ◽  
Rna Polymerase Ii ◽  
Liver Tissue ◽  
Drug Disposition ◽  
Multiple Drug ◽  
Proteomic Profiling ◽  
Cytochrome P450 3A ◽  
Drug Induced

AbstractHepatic organoids are a recent innovation in in vitro modeling. Initial studies suggest that organoids better recapitulate the liver phenotype in vitro compared to pre-existing proliferative cell models. However, their potential for drug metabolism and detoxification remains poorly characterized, and their global proteome has yet to be compared to their tissue of origin. This analysis is urgently needed to determine what gain-of-function this new model may represent for modeling the physiological and toxicological response of the liver to xenobiotics. Global proteomic profiling of undifferentiated and differentiated hepatic murine organoids and donor-matched livers was, therefore, performed to assess both their similarity to liver tissue, and the expression of drug-metabolizing enzymes and transporters. This analysis quantified 4405 proteins across all sample types. Data are available via ProteomeXchange (PXD017986). Differentiation of organoids significantly increased the expression of multiple cytochrome P450, phase II enzymes, liver biomarkers and hepatic transporters. While the final phenotype of differentiated organoids is distinct from liver tissue, the organoids contain multiple drug metabolizing and transporter proteins necessary for liver function and drug metabolism, such as cytochrome P450 3A, glutathione-S-transferase alpha and multidrug resistance protein 1A. Indeed, the differentiated organoids were shown to exhibit increased sensitivity to midazolam (10–1000 µM) and irinotecan (1–100 µM), when compared to the undifferentiated organoids. The predicted reduced activity of HNF4A and a resulting dysregulation of RNA polymerase II may explain the partial differentiation of the organoids. Although further experimentation, optimization and characterization is needed relative to pre-existing models to fully contextualize their use as an in vitro model of drug-induced liver injury, hepatic organoids represent an attractive novel model of the response of the liver to xenobiotics. The current study also highlights the utility of global proteomic analyses for rapid and accurate evaluation of organoid-based test systems.

scholarly journals Pharmacological targeting of host chaperones protects from pertussis toxin in vitro and in vivo

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katharina Ernst ◽  
Ann-Katrin Mittler ◽  
Veronika Winkelmann ◽  
Carolin Kling ◽  
Nina Eberhardt ◽  
...  
Keyword(s):  
Pertussis Toxin ◽  
Airway Epithelium ◽  
Whooping Cough ◽  
Apical Surface ◽  
Basal Cells ◽  
Pharmacological Chaperone ◽  
Infant Mouse ◽  
Novel Therapeutic Strategies

AbstractWhooping cough is caused by Bordetella pertussis that releases pertussis toxin (PT) which comprises enzyme A-subunit PTS1 and binding/transport B-subunit. After receptor-mediated endocytosis, PT reaches the endoplasmic reticulum from where unfolded PTS1 is transported to the cytosol. PTS1 ADP-ribosylates G-protein α-subunits resulting in increased cAMP signaling. Here, a role of target cell chaperones Hsp90, Hsp70, cyclophilins and FK506-binding proteins for cytosolic PTS1-uptake is demonstrated. PTS1 specifically and directly interacts with chaperones in vitro and in cells. Specific pharmacological chaperone inhibition protects CHO-K1, human primary airway basal cells and a fully differentiated airway epithelium from PT-intoxication by reducing intracellular PTS1-amounts without affecting cell binding or enzyme activity. PT is internalized by human airway epithelium secretory but not ciliated cells and leads to increase of apical surface liquid. Cyclophilin-inhibitors reduced leukocytosis in infant mouse model of pertussis, indicating their promising potential for developing novel therapeutic strategies against whooping cough.

scholarly journals Efficient functional cyst formation of biliary epithelial cells using microwells for potential bile duct organisation in vitro

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Astia Rizki-Safitri ◽  
Marie Shinohara ◽  
Yasushi Miura ◽  
Mathieu Danoy ◽  
Minoru Tanaka ◽  
...  
Keyword(s):  
Bile Duct ◽  
Epithelial Cells ◽  
Cyst Formation ◽  
Biliary Epithelial Cells

Antagonism of endogenous putative P2Y receptors reduces the growth of MDCK-derived cysts cultured in vitro

2007 ◽  
Vol 292 (1) ◽  
pp. F15-F25 ◽  
Author(s):  
Clare M. Turner ◽  
Brian F. King ◽  
Kaila S. Srai ◽  
Robert J. Unwin
Keyword(s):  
Therapeutic Potential ◽  
Cyst Formation ◽  
P2y Receptors ◽  
P2x Receptor ◽  
P2y Receptor ◽  
Cyst Size ◽  
Reactive Blue 2 ◽  
Cyst Growth

P2Y receptors couple to G proteins and either mobilize intracellular Ca2+ or alter cAMP levels to modulate the activity of Ca2+- and cAMP-sensitive ion channels. We hypothesize that increased ion transport into the lumen of MDCK cysts can osmotically drive fluid movement and increase cyst size. Furthermore, activation of the adenylate cyclase/cAMP pathway may trigger cell proliferation via an extracellular signal-related kinase cascade. To test this hypothesis, several P2Y receptor inhibitors were used on the MDCK in vitro model of renal cyst formation. The nonspecific P2 receptor inhibitors reactive blue 2 and suramin reduced cyst growth significantly, as did PPADS and, to a lesser extent, the P2Y1-specific antagonist MRS2179. Cyst growth was reduced by ∼50% when ATP was removed from the culture medium with apyrase, although stable analogs of ATP failed to increase cyst size. The nonselective P2X receptor inhibitor Coomassie brilliant blue G was ineffective at reducing cyst growth, suggesting no involvement of P2X receptors. Finally, the presence of selective inhibitors of ERK activation (either PD98059 or U0126) greatly reduced cyst growth, whereas in untreated cysts ERK activity was observed to increase with time. We conclude that stimulation of endogenous P2Y receptors by extracellular ATP increases growth of MDCK cysts via cAMP-dependent activation of the ERK pathway. P2Y receptor antagonists may have therapeutic potential in reducing cyst size and slowing disease progression; although further studies in vitro and in vivo are needed to investigate the specificity and role of these P2Y receptors in renal cystic diseases.

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