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https://www.readbyqxmd.com/read/28905451/gene-edited-human-kidney-organoids-reveal-mechanisms-of-disease-in-podocyte-development
#1
Yong Kyun Kim, Ido Refaeli, Craig R Brooks, Peifeng Jing, Ramila E Gulieva, Michael R Hughes, Nelly M Cruz, Yannan Liu, Angela J Churchill, Yuliang Wang, Hongxia Fu, Jeffrey W Pippin, Lih Y Lin, Stuart J Shankland, A Wayne Vogl, Kelly M McNagny, Benjamin S Freedman
A critical event during kidney organogenesis is the differentiation of podocytes, specialized epithelial cells that filter blood plasma to form urine. Podocytes derived from human pluripotent stem cells (hPSC-podocytes) have recently been generated in nephron-like kidney organoids, but the developmental stage of these cells and their capacity to reveal disease mechanisms remains unclear. Here we show that hPSC-podocytes phenocopy mammalian podocytes at the capillary loop stage (CLS), recapitulating key features of ultrastructure, gene expression, and mutant phenotype...
September 14, 2017: Stem Cells
https://www.readbyqxmd.com/read/28898451/comparative-ultrastructure-of-coxal-glands-in-unfed-larvae-of-leptotrombidium-orientale-schluger-1948-trombiculidae-and-hydryphantes-ruber-de-geer-1778-hydryphantidae
#2
Andrey B Shatrov
Coxal glands of unfed larvae Leptotrombidium orientale (Schluger, 1948) (Trombiculidae), a terrestrial mite parasitizing vertebrates, and Hydryphantes ruber (de Geer, 1778) (Hydryphantidae), a water mite parasitizing insects were studied using transmission electron microscopy. In both species, the coxal glands are represented by a paired tubular organ extending on the sides of the brain from the mouthparts to the frontal midgut wall and are formed of the cells arranged around the central lumen. As in other Parasitengona, the coxal glands are devoid of a proximal sacculus...
September 12, 2017: Journal of Morphology
https://www.readbyqxmd.com/read/28855375/shear-stress-induces-non-canonical-autophagic-flux-in-intestinal-epithelial-monolayers
#3
Sun Wook Kim, Jonathan Ehrman, Mok-Ryeon Ahn, Jumpei Kondo, Andrea A Mancheno Lopez, Yun Sik Oh, Hanjune X Kim, Scott W Crawley, James R Goldenring, Matthew J Tyska, Erin C Rericha, Ken S Lau
Flow of fluids through the gut, such as milk from a neonatal diet, generates a shear stress on the unilaminar epithelium lining the lumen.  We report that exposure to physiological levels of fluid shear stress leads to the formation of large vacuoles, containing extracellular content, within polarizing intestinal epithelial cell monolayers.  These observations lead to two questions: how can cells lacking primary cilia transduce shear stress, and what molecular pathways support the formation of vacuoles that can exceed 80% of the cell volume...
August 30, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28846140/an-examination-of-surface-epithelium-structures-of-the-embryo-across-the-genus-poeciliopsis-poeciliidae
#4
Tami M Panhuis, Megan Fris, Laura Tuhela, Lucia Kwan
In viviparous, teleost fish, with postfertilization maternal nutrient provisioning, embryonic structures that facilitate maternal-fetal nutrient transfer are predicted to be present. For the family Poeciliidae, only a handful of morphological studies have explored these embryonic specializations. Here, we present a comparative morphological study in the viviparous poeciliid genus, Poeciliopsis. Using microscopy techniques, we examine the embryonic surface epidermis of Poeciliopsis species that vary in their level of postfertilization maternal nutrient provisioning and placentation across two phylogenetic clades and three independent evolutionary origins of placentation...
August 28, 2017: Journal of Morphology
https://www.readbyqxmd.com/read/28837408/intestinal-surfactant-permeation-enhancers-and-their-interaction-with-enterocyte-cell-membranes-in-a-mucosal-explant-system
#5
E Michael Danielsen, Gert H Hansen
Intestinal permeation enhancers (PEs) are agents aimed to improve oral delivery of therapeutic drugs with poor bioavailability. The main permeability barrier for oral delivery is the intestinal epithelium, and PEs act to increase the paracellular and/or transcellular passage of drugs. Transcellular passage can be achieved by cell membrane permeabilization and/or by endocytic uptake and subsequent transcytosis. One broad class of PEs is surfactants which act by inserting into the cell membrane, thereby perturbing its integrity, but little is known about how the dynamics of the membrane are affected...
July 3, 2017: Tissue Barriers
https://www.readbyqxmd.com/read/28830330/ultrastructural-alterations-in-thyrocytes-of-zebrafish-danio-rerio-after-exposure-to-propylthiouracil-and-perchlorate
#6
Florian Schmidt, Raoul Wolf, Lisa Baumann, Thomas Braunbeck
Histopathology is a widely used approach to evaluate effects of endocrine-active chemicals in the thyroid. However, effects at an ultrastructural level have hardly been examined in fish thyroids. In the present study, zebrafish was exposed to sublethal concentrations of propylthiouracil (PTU; 0-50 mg/L) and perchlorate (PER; 0-5,000 µg/L) for 5 weeks in a modified early life-stage test. None of the treatments caused significant mortality (no observed effect concentrations for survival ≥50 mg/L [PTU] and ≥5,000 µg/L [PER])...
July 2017: Toxicologic Pathology
https://www.readbyqxmd.com/read/28825699/an-apical-mrck-driven-morphogenetic-pathway-controls-epithelial-polarity
#7
Ceniz Zihni, Evi Vlassaks, Stephen Terry, Jeremy Carlton, Thomas King Chor Leung, Michael Olson, Franck Pichaud, Maria Susana Balda, Karl Matter
Polarized epithelia develop distinct cell surface domains, with the apical membrane acquiring characteristic morphological features such as microvilli. Cell polarization is driven by polarity determinants including the evolutionarily conserved partitioning-defective (PAR) proteins that are separated into distinct cortical domains. PAR protein segregation is thought to be a consequence of asymmetric actomyosin contractions. The mechanism of activation of apically polarized actomyosin contractility is unknown...
September 2017: Nature Cell Biology
https://www.readbyqxmd.com/read/28815590/juxtanodin-in-retinal-pigment-epithelial-cells-expression-and-biological-activities-in-regulating-cell-morphology-and-actin-cytoskeleton-organization
#8
Fengyi Liang, Ji Hyun Hwang, Nicholas Weiwei Tang, Walter Hunziker
Juxtanodin (also known as ermin) was initially identified as an actin cytoskeleton-related oligodendroglial protein in the rat central nervous system. It was subsequently also found in the rat olfactory neuroepithelium, especially at the apical junctional belt of the sustentacular cells. We further examined juxtanodin expression and functional roles in the retina using fluorescence histochemistry, confocal microscopy, immuno-electron microscopy, molecular biology and cell culture. Prominent juxtanodin expression was found in the photoreceptor-supporting retinal pigment epithelium (RPE), especially in a zone corresponding to the apices of RPE cells, at the roots of the RPE microvilli, and at the base of RPE cells next to the Bruch's membrane...
August 17, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28789587/light-on-a-sensory-interface-linking-the-cerebrospinal-fluid-to-motor-circuits-in-vertebrates
#9
Lydia Djenoune, Claire Wyart
The cerebrospinal fluid (CSF) is circulating around the entire central nervous system (CNS). The main function of the CSF has been thought to insure the global homeostasis of the CNS. Recent evidence indicates that the CSF also dynamically conveys signals modulating the development and the activity of the nervous system. The later observation implies that cues from the CSF could act on neurons in the brain and the spinal cord via bordering receptor cells. Candidate neurons to enable such modulation are the cerebrospinal fluid-contacting neurons (CSF-cNs) that are located precisely at the interface between the CSF and neuronal circuits...
September 2017: Journal of Neurogenetics
https://www.readbyqxmd.com/read/28709848/hydrogen-sulfide-alleviates-placental-injury-induced-by-maternal-cigarette-smoke-exposure-during-pregnancy-in-rats
#10
Fusheng Zhao, Fang Lei, Senfeng Zhang, Xiang Yan, Wen Wang, Yu Zheng
Maternal cigarette smoke exposure (CSE) during pregnancy is a well recognized causative factor for placental injury. Hydrogen sulfide (H2S), a gaseous signal molecule, has been shown to exert a protective effect against tissue injury in many organs. This study aimed to investigate whether H2S could alleviate CSE-induced placental injury in rats. Pregnant SD rats were randomly divided into 4 groups: NaCl, CSE, CSE + NaHS (a donor of H2S) and NaHS. On gestational day 21, placental weight was measured. Placental H2S content was assessed by methylene blue method...
July 11, 2017: Nitric Oxide: Biology and Chemistry
https://www.readbyqxmd.com/read/28691238/structure-and-ultrastructure-of-eyes-and-brains-of-thalia-democratica-thaliacea-tunicata-chordata
#11
Katrin Braun, Thomas Stach
Salps are marine planktonic chordates that possess an obligatory alternation of reproductive modes in subsequent generations. Within tunicates, salps represent a derived life cycle and are of interest in considerations of the evolutionary origin of complex anatomical structures and life history strategies. In the present study, the eyes and brains of both the sexual, aggregate blastozooid and the asexual, solitary oozooid stage of Thalia democratica (Forskål, ) were digitally reconstructed in detail based on serial sectioning for light and transmission electron microscopy...
July 10, 2017: Journal of Morphology
https://www.readbyqxmd.com/read/28668562/origin-and-characterization-of-small-membranous-vesicles-present-in-the-venom-of-crotalus-durissus-terrificus
#12
Andréia Souza-Imberg, Sylvia Mendes Carneiro, Karina Cristina Giannotti, Sávio Stefanini Sant'Anna, Norma Yamanouye
Small membranous vesicles are small closed fragments of membrane. They are released from multivesicular bodies (exosomes) or shed from the surface membrane (microvesicles). They contains various bioactive molecules and their molecular composition varies depending on their cellular origin. Small membranous vesicles have been identified in snake venoms, but the origin of these small membranous vesicles in the venom is controversial. The aim of this study was to verify the origin of the small membranous vesicles in venom of Crotalus durissus terrificus by morphological analyses using electron microscopy...
June 28, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28636623/the-basolateral-vesicle-sorting-machinery-and-basolateral-proteins-are-recruited-to-the-site-of-enteropathogenic-e-coli-microcolony-growth-at-the-apical-membrane
#13
Gitte A Pedersen, Helene H Jensen, Anne-Sofie B Schelde, Charlotte Toft, Hans N Pedersen, Maj Ulrichsen, Frédéric H Login, Manuel R Amieva, Lene N Nejsum
Foodborne Enteropathogenic Escherichia coli (EPEC) infections of the small intestine cause diarrhea especially in children and are a major cause of childhood death in developing countries. EPEC infects the apical membrane of the epithelium of the small intestine by attaching, effacing the microvilli under the bacteria and then forming microcolonies on the cell surface. We first asked the question where on epithelial cells EPEC attaches and grows. Using models of polarized epithelial monolayers, we evaluated the sites of initial EPEC attachment to the apical membrane and found that EPEC preferentially attached over the cell-cell junctions and formed microcolonies preferentially where three cells come together at tricellular tight junctions...
2017: PloS One
https://www.readbyqxmd.com/read/28596241/disruption-of-rab8a-and-rab11a-causes-formation-of-basolateral-microvilli-in-neonatal-enteropathy
#14
Qiang Feng, Edward M Bonder, Amy C Engevik, Lanjing Zhang, Matthew J Tyska, James R Goldenring, Nan Gao
Misplaced formation of microvilli to basolateral domains and intracellular inclusions in enterocytes are pathognomonic features in congenital enteropathy associated with mutation of the apical plasma membrane receptor syntaxin 3 (STX3). Although the demonstrated binding of Myo5b to the Rab8a and Rab11a small GTPases in vitro implicates cytoskeleton-dependent membrane sorting, the mechanisms underlying the microvillar location defect remain unclear. By selective or combinatory disruption of Rab8a and Rab11a membrane traffic in vivo, we demonstrate that transport of distinct cargo to the apical brush border rely on either individual or both Rab regulators, whereas certain basolateral cargos are redundantly transported by both factors...
August 1, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/28595928/histopathological-effects-of-cypermethrin-and-bacillus-thuringiensis-var-israelensis-on-midgut-of-chironomus-calligraphus-larvae-diptera-chironomidae
#15
Sabrina Lavarías, Florencia Arrighetti, Augusto Siri
Pesticides are extensively used for the control of agricultural pests and disease vectors, but they also affect non-target organisms. Cypermethrin (CYP) is a synthetic pyrethroid used worldwide. Otherwise, bioinsecticides like Bacillus thuringiensis var. israelensis (Bti) have received great attention as an environmentally benign and desirable alternative. In order to evaluate the toxicity of those pesticides, Chironomus calligraphus was selected due to its high sensitivity to some toxicants. Third and fourth instars larvae were exposed to serial dilutions of CYP and Bti to determine LC50 values...
June 2017: Pesticide Biochemistry and Physiology
https://www.readbyqxmd.com/read/28548701/microtubules-regulate-brush-border-formation
#16
Facundo M Tonucci, Anabela Ferretti, Evangelina Almada, Pamela Cribb, Rodrigo Vena, Florencia Hidalgo, Cristián Favre, Matt J Tyska, Irina Kaverina, M Cecilia Larocca
Most epithelial cells contain apical membrane structures associated to bundles of actin filaments, which constitute the brush border. Whereas microtubule participation in the maintenance of the brush border identity has been characterized, their contribution to de novo microvilli organization remained elusive. Hereby, using a cell model of individual enterocyte polarization, we found that nocodazole induced microtubule depolymerization prevented the de novo brush border formation. Microtubule participation in brush border actin organization was confirmed in polarized kidney tubule MDCK cells...
May 26, 2017: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/28500222/energy-requirements-of-odor-transduction-in-the-chemosensory-cilia-of-olfactory-sensory-neurons-rely-on-oxidative-phosphorylation-and-glycolytic-processing-of-extracellular-glucose
#17
Pablo S Villar, Ricardo Delgado, Cecilia Vergara, Juan G Reyes, Juan Bacigalupo
The mechanisms that power the physiological events occurring in cilia, flagella, and microvilli are of fundamental importance for the functions of these important and ubicuous organelles. The olfactory epithelium is mostly populated by ciliated olfactory sensory neurons (OSNs) and surrounding sustentacular cells (SCs) with apical microvilli. The only OSN dendrite extends to the surface forming a knob projecting several chemosensory cilia of ∼50 × 0.2 μm, devoid of inner membranes embedded in a mucus layer...
June 7, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28467791/dry-age-related-macular-degeneration-like-pathology-in-aged-5xfad-mice-ultrastructure-and-microarray-analysis
#18
Sung Wook Park, Sora Im, Hyoung Oh Jun, Kihwang Lee, Young-Jun Park, Jin Hyoung Kim, Woo Jin Park, Young-Hoon Lee, Jeong Hun Kim
Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly. The two types of AMD are: dry and wet AMD. While laser-induced choroidal neovascularization has been used extensively in the studies of wet AMD, there is no established mouse model that fully recapitulates the cardinal features of dry AMD. A lack of appropriate mouse model for dry AMD has hampered the translational research on the pathogenesis of the disease and the development of therapeutic agents. We hypothesized that 5XFAD mice, an animal model for the study of Alzheimer's disease, can be used as a mouse model for dry AMD with regard to the amyloid beta (Aβ) related pathology...
June 20, 2017: Oncotarget
https://www.readbyqxmd.com/read/28430576/ezrin-activation-by-lok-phosphorylation-involves-a-pip2-dependent-wedge-mechanism
#19
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
#20
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 (3× Myosin 5b mutations and 1× Syntaxin3 mutation) and compared them to controls and genome-edited CaCo2 cell models, harboring relevant mutations...
April 13, 2017: Traffic
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