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Apical microvilli

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https://www.readbyqxmd.com/read/28430576/ezrin-activation-by-lok-phosphorylation-involves-a-pip2-dependent-wedge-mechanism
#1
Thaher Pelaseyed, Cécile Sauvanet, Raghuvir Viswanatha, Joshua J Filter, Michael L Goldberg, Anthony Bretscher
How cells specify morphologically distinct plasma membrane domains is poorly understood. Prior work has shown that restriction of microvilli to the apical aspect of epithelial cells requires the localized activation of the membrane-F-actin linking protein ezrin. Using an in vitro system, we now define a multi-step process whereby the kinase LOK specifically phosphorylates ezrin to activate it. Binding of PIP2 to ezrin induces a conformational change permitting the insertion of the LOK C-terminal domain to wedge apart the membrane and F-actin-binding domains of ezrin...
April 21, 2017: ELife
https://www.readbyqxmd.com/read/28407399/abnormal-rab11-rab8-vesicles-cluster-in-enterocytes-of-patients-with-microvillus-inclusion-disease
#2
Georg F Vogel, Andreas R Janecke, Iris M Krainer, Karin Gutleben, Barbara Witting, Sally G Mitton, Sahar Mansour, Antje Ballauff, Joseph T Roland, Amy C Engevik, Ernest Cutz, Thomas Müller, James R Goldenring, Lukas A Huber, Michael W Hess
Microvillus Inclusion Disease (MVID) is a congenital enteropathy characterized by accumulation of vesiculo-tubular endomembranes in the subapical cytoplasm of enterocytes, historically termed "secretory granules". However, neither their identity nor pathophysiological significance is well defined. Using immunoelectron microscopy and tomography we studied biopsies from MVID patients (3x Myosin 5b mutations, 1x Syntaxin3 mutation) and compared them to controls and genome-edited CaCo2 cell models, harboring relevant mutations...
April 13, 2017: Traffic
https://www.readbyqxmd.com/read/28401359/ultrastructure-of-fat-body-cells-and-malpighian-tubule-cells-in-overwintering-scoliopteryx-libatrix-noctuoidea
#3
Saška Lipovšek, Franc Janžekovič, Tone Novak
The herald moths, Scoliopteryx libatrix, overwinter in hypogean habitats. The ultrastructure of their fat body (FB) cells and Malpighian tubule (MT) epithelial cells was studied by light microscopy and transmission electron microscopy, and essential biometric and biochemical measurements were performed. The FB was composed of adipocytes and sparse urocytes. The ultrastructure of both cells did not change considerably during this natural starvation period, except for rough endoplasmic reticulum (rER) which became more abundant in March females...
April 11, 2017: Protoplasma
https://www.readbyqxmd.com/read/28363254/pancreatic-neuroendocrine-carcinoma-with-exocrine-differentiation-in-a-young-cat
#4
Masaki Michishita, Mariko Takagi, Takuya E Kishimoto, Rei Nakahira, Takeshi Nogami, Hisashi Yoshimura, Hitoshi Hatakeyama, Daigo Azakami, Kazuhiko Ochiai, Kimimasa Takahashi
A 35-mo-old spayed female mixed-breed cat with continuous vomiting, emaciation, and abdominal distention for 2 wk was presented to a private veterinary clinic for evaluation. At 71 d after the initial visit, the cat died with anemia, jaundice, and hypoalbuminemia, and was subjected to autopsy. Grossly, numerous firm masses, 0.5-2.5 cm diameter, were randomly located in the left lobe of the pancreas. Histologic examination revealed that the pancreatic mass consisted of 2 tumor cell types: mostly small round cells with a minority of epithelial cells...
March 1, 2017: Journal of Veterinary Diagnostic Investigation
https://www.readbyqxmd.com/read/28265783/t84-monolayers-are-superior-to-caco-2-as-a-model-system-of-colonocytes
#5
Sarah Devriese, Lien Van den Bossche, Sophie Van Welden, Tom Holvoet, Iris Pinheiro, Pieter Hindryckx, Martine De Vos, Debby Laukens
Colonic adenocarcinoma-derived Caco-2 and T84 epithelial cell lines are frequently used as in vitro model systems of functional epithelial barriers. Both are utilised interchangeably despite evidence that differentiated Caco-2 cells are more reminiscent of small intestinal enterocytes than of colonocytes, whereas differentiated T84 cells are less well characterised. The aim of this study was, therefore, to further characterise and compare differentiated Caco-2 and T84 cells. The objectives were to (1) compare the brush border morphology, (2) measure the expression of enterocyte- and colonocyte-specific genes and (3) compare their response to butyrate, which is dependent on the monocarboxylate transporter 1 (MCT1), an apical protein expressed primarily in colonocytes...
March 6, 2017: Histochemistry and Cell Biology
https://www.readbyqxmd.com/read/28264821/role-of-polarity-proteins-in-the-generation-and-organization-of-apical-surface-protrusions
#6
Gerard Apodaca
Protruding from the apical surfaces of epithelial cells are specialized structures, including cilia, microplicae, microvilli, and stereocilia. These contribute to epithelial function by cushioning the apical surface, by amplifying its surface area to facilitate nutrient absorption, and by promoting sensory transduction and barrier function. Despite these important roles, and the diseases that result when their formation is perturbed, there remain significant gaps in our understanding of the biogenesis of apical protrusions, or the pathways that promote their organization and orientation once at the apical surface...
March 6, 2017: Cold Spring Harbor Perspectives in Biology
https://www.readbyqxmd.com/read/28187870/the-unique-organization-of-filamentous-actin-in-the-medullary-canal-of-the-medulla-oblongata
#7
Bai-Hong Tan, Chun-Yan Guo, Tian-Qing Xiong, Ling-Meng Chen, Yan-Chao Li
In the central canal, F-actin is predominantly localized in the apical region, forming a ring-like structure around the circumference of the lumen. However, an exception is found in the medulla oblongata, where the apical F-actin becomes interrupted in the ventral aspect of the canal. To clarify the precise localization of F-actin, the fluorescence signals for F-actin were converted to the peroxidase/DAB reaction products in this study by a phalloidin-based ultrastructural technique, which demonstrated that F-actin is located mainly in the microvilli and terminal webs in the ependymocytes...
April 2017: Tissue & Cell
https://www.readbyqxmd.com/read/28159658/the-rat-vomeronasal-organ-is-a-vitamin-d-target
#8
A Rodewald, V M Gebhart, H Oehring, G F Jirikowski
We studied the expression of vitamin D receptor and of vitamin D binding protein in the rat vomeronasal organ. With immunofluorescence, in situ hybridization and with reverse transcriptase PCR we found both proteins in sensory as well as in non-sensory cells. Sensory neurons contained immunoreactivity for vitamin D3 receptor in nuclei, in portions of the cytoplasm, and in apical dendrites and their microvilli. Vitamin D binding protein was observed in sensory neuron axons and cytoplasm, mostly confined to dendrites...
January 31, 2017: Journal of Chemical Neuroanatomy
https://www.readbyqxmd.com/read/28052271/establishment-and-characterization-of-an-sv40-large-t-antigen-transduced-porcine-colonic-epithelial-cell-line
#9
Bastian Kaiser, Martina Böttner, Thilo Wedel, Ronald M Brunner, Tom Goldammer, Szilvia Lesko, Gotthold Gäbel, Alexander Gleich, Helga Pfannkuche
Continuous cell lines have become indispensable tools that have enabled investigations into cellular mechanisms by increasing experimental reproducibility and sample availability, and decreasing the use of experimental animals. To facilitate studies of epithelial barrier function of the porcine colon, we aimed to establish an epithelial cell line with an extended replicative capacity. Cells were isolated from the proximal colon of a 3-week-old piglet and transduced using a recombinant retroviral vector construct containing the simian virus 40 large T antigen (SV40 TAg)...
January 5, 2017: Cells, Tissues, Organs
https://www.readbyqxmd.com/read/27882813/dietary-zinc-modifies-diabetic-induced-renal-pathology-in-rats
#10
Wael M Elsaed, Hazem Abdelhamid Mohamed
This study was conducted to investigate how far dietary zinc (Zn) modifies the histomorphological alterations induced by diabetes in rat kidneys. The animals were divided into negative control group (10 rats). Diabetes was induced in thirty animals by streptozotocin. After confirming diabetes, the animals were divided into three groups (n = 10). Group II served as the positive control group (fed on standard diet), group III was fed on Zn deficient diet, and group IV was fed on Zn supplemented diet. Caspase-3 immune staining was used to estimate the caspase activity...
November 24, 2016: Renal Failure
https://www.readbyqxmd.com/read/27859898/structural-and-ultrastructural-features-of-the-malpighian-tubules-of-dolycoris-baccarum-linnaeus-1758-heteroptera-pentatomidae
#11
Nurcan Özyurt, Damla Amutkan, Irmak Polat, Tenay Kocamaz, Selami Candan, Zekiye Suludere
The morphology and ultrastructure of the Malpighian tubules of Dolycoris baccarum were analyzed by scanning (SEM) and transmission (TEM) electron microscopy in order to determine their functional organization. The Malpighian tubules are compared with similar structures of other insects based on cell structure and functional organization. The Malpighian tubules of D. baccarum extend from the midgut-hindgut region of the digestive tract. The Malpighian tubules are divided into two regions: the proximal segment is short and flattened and the distal segment is long, stringy in shape and free in hemolymph...
April 2017: Microscopy Research and Technique
https://www.readbyqxmd.com/read/27856525/microvilli-morphology-can-affect-efflux-active-p-glycoprotein-in-confluent-mdckii-nki_hmdr1-and-caco-2-cell-monolayers
#12
Zhou Meng, Sylvain Le Marchand, Deep Agnani, Matt Szapacs, Harma Ellens, Joe Bentz
From fits of drug transport kinetics across confluent MDCKII-hMDR1-NKI and Caco-2 cell monolayers we estimated the levels of efflux active P-glycoprotein (P-gp) in these two cell lines (companion paper, Meng at el., 2016a). In the present work, we compared the efflux active P-gp number to the total P-gp level, using LC/MSMS, and showed that in Caco-2 cells total P-gp is about 10-fold greater than efflux active P-gp, while in MDCKII-hMDR1-NKI cells these values are within 2-fold. We further visualized the microvilli in MDCKII-hMDR1-NKI and Caco-2 cells using three-dimensional structured illumination super-resolution microscopy and found that the microvilli in Caco-2 cells are taller and more densely packed than those in MDCK-NKI-hMDR1 cells...
November 16, 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/27846033/brush-cells-the-newly-identified-gatekeepers-of-the-urinary-tract
#13
Wolfgang Kummer, Klaus Deckmann
PURPOSE OF REVIEW: A specialized epithelial cell with chemosensory properties of taste cells known from the mouth has been newly identified in the urethra and linked to pathogen recognition. We here describe its properties and its link to defence mechanisms, showing parallels to similar sentinel cells in the respiratory and gastrointestinal tract. RECENT FINDINGS: In the urethra, slender epithelial cells with apical microvilli ('brush cells') express bitter and umami taste receptors and the downstream signalling cascade known from oropharyngeal gustation, utilizing it to monitor for bacterial products and bacterial growth facilitating conditions...
March 2017: Current Opinion in Urology
https://www.readbyqxmd.com/read/27825102/microvillar-injury-in-renal-tubular-epithelial-cells-induced-by-calcium-oxalate-crystal-and-the-protective-role-of-epigallocatechin-3-gallate
#14
Kedsarin Fong-Ngern, Arada Vinaiphat, Visith Thongboonkerd
Pathogenic mechanisms of kidney stone disease remained unclear. This study investigated its initial cellular/molecular mechanisms when calcium oxalate monohydrate (COM) crystal adhered to renal tubular cells. Transmission electron microscopy revealed decreased length and density of microvilli, whereas Western blot analysis showed that whole-cell ezrin (a microvillus-stabilizing protein), not β-actin, was decreased in COM-treated cells. Immunofluorescence staining, followed by laser-scanning confocal microscopy and subcellular fractionations, revealed decreases in both ezrin and F-/β-actin at apical membrane...
January 2017: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/27823775/similar-expression-pattern-of-nherf1-and-ezrin-in-papillary-but-not-in-solid-areas-of-human-serous-ovarian-carcinomas
#15
Brenda Demacopulo, Baltazar Eduardo Lema, Rómulo Luis Cabrini, Erica Lorena Kreimann
NHERF1 is an adaptor protein expressed in the apical membrane of polarized epithelia, which interacts with the EZRIN-Radixin-Moesin (ERM) family of proteins connecting signaling pathways to the cell cytoskeleton. NHERF1 and EZRIN cooperate in the maintenance of the apical microvilli in polarized epithelial cells. In several types of cancers, NHERF1 and EZRIN are displaced from the apical compartment to the cytoplasm and nuclei of cancer cells. At the present, the distribution of NHERF1 in ovarian tumors is not well known...
October 2016: Acta Histochemica
https://www.readbyqxmd.com/read/27797725/morphology-and-distribution-of-taste-papillae-and-oral-denticles-in-the-developing-oropharyngeal-cavity-of-the-bamboo-shark-chiloscyllium-punctatum
#16
Carla J L Atkinson, Kyle J Martin, Gareth J Fraser, Shaun P Collin
Gustation in sharks is not well understood, especially within species that ingest food items using suction. This study examines the morphological and immunohistochemical characterisation of taste papillae and oral denticles in the oropharynx of the brown-banded bamboo shark Chiloscyllium punctatum and compares their distribution during development. Taste papillae of C. punctatum are located throughout the oropharyngeal region and are most concentrated on the oral valves (2125-3483 per cm(2) in embryos; 89-111 per cm(2) in mature adults) close to the tooth territories...
December 15, 2016: Biology Open
https://www.readbyqxmd.com/read/27776163/potential-use-of-autologous-renal-cells-from-diseased-kidneys-for-the-treatment-of-renal-failure
#17
Sunil K George, Mehran Abolbashari, John D Jackson, Tamer Aboushwareb, Anthony Atala, James J Yoo
Chronic kidney disease (CKD) occurs when certain conditions cause the kidneys to gradually lose function. For patients with CKD, renal transplantation is the only treatment option that restores kidney function. In this study, we evaluated primary renal cells obtained from diseased kidneys to determine whether their normal phenotypic and functional characteristics are retained, and could be used for cell therapy. Primary renal cells isolated from both normal kidneys (NK) and diseased kidneys (CKD) showed similar phenotypic characteristics and growth kinetics...
2016: PloS One
https://www.readbyqxmd.com/read/27680547/chemosensory-epithelial-cells-in-the-urethra-sentinels-of-the-urinary-tract
#18
REVIEW
Klaus Deckmann, Wolfgang Kummer
A peculiar cell type of the respiratory and gastrointestinal epithelia, originally termed "brush cell" or "tuft cell" by electron microscopists because of its apical tuft of microvilli, utilizes the canonical bitter taste transduction cascade known from oropharyngeal taste buds to detect potential hazardous compounds, e.g. bacterial products. Upon stimulation, this cell initiates protective reflexes and local inflammatory responses through release of acetylcholine and chemokines. Guided by the understanding of these cells as sentinels, they have been newly discovered at previously unrecognized anatomical locations, including the urethra...
December 2016: Histochemistry and Cell Biology
https://www.readbyqxmd.com/read/27677532/doublecortin-like-kinase-1-positive-enterocyte-a-new-cell-type-in-human-intestine
#19
Joni Leppänen, Olli Helminen, Heikki Huhta, Joonas H Kauppila, Ilkka Miinalainen, Veli-Pekka Ronkainen, Juha Saarnio, Petri P Lehenkari, Tuomo J Karttunen
Doublecortin-like kinase 1 (DCLK1) is a microtubule-associated kinase. In murine intestine, DCLK1 marks tuft cells with characteristic microvilli, features of neuroendocrine cells and also quiescent stem cell-like properties. The occurrence and pathological role of DCLK1-positive cells in human intestinal mucosa is unknown. We analysed DCLK1 expression in healthy duodenal, jejunal and colorectal mucosa samples (n = 35), and in duodenal specimens from patients with coeliac disease (n = 20). The samples were immunohistochemically double-stained with DCLK1, and synaptophysin, chromogranin A and Ki-67...
November 2016: APMIS: Acta Pathologica, Microbiologica, et Immunologica Scandinavica
https://www.readbyqxmd.com/read/27666969/myosin-7b-promotes-distal-tip-localization-of-the-intermicrovillar-adhesion-complex
#20
Meredith L Weck, Scott W Crawley, Colin R Stone, Matthew J Tyska
Transporting epithelial cells interact with the luminal environment using a tightly packed array of microvilli known as the brush border. During intestinal epithelial differentiation, microvillar packing and organization are driven by cadherin-dependent adhesion complexes that localize to the distal tips of microvilli, where they drive physical interactions between neighboring protrusions. Although enrichment of the "intermicrovillar adhesion complex" (IMAC) at distal tips is required for proper function, the mechanism driving tip accumulation of these factors remains unclear...
October 24, 2016: Current Biology: CB
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