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Tianhong Wang, Susan Hamilla, Maggie Cam, Helim Aranda-Espinoza, Stavroula Mili
Numerous RNAs are enriched within cellular protrusions, but the underlying mechanisms are largely unknown. We had shown that the APC (adenomatous polyposis coli) protein controls localization of some RNAs at protrusions. Here, using protrusion-isolation schemes and RNA-Seq, we find that RNAs localized in protrusions of migrating fibroblasts can be distinguished in two groups, which are differentially enriched in distinct types of protrusions, and are additionally differentially dependent on APC. APC-dependent RNAs become enriched in high-contractility protrusions and, accordingly, their localization is promoted by increasing stiffness of the extracellular matrix...
October 12, 2017: Nature Communications
Paula Schiapparelli, Hugo Guerrero-Cazares, Roxana Magaña-Maldonado, Susan M Hamilla, Sara Ganaha, Eric Goulin Lippi Fernandes, Chuan-Hsiang Huang, Helim Aranda-Espinoza, Peter Devreotes, Alfredo Quinones-Hinojosa
Glioblastoma (GBM) is the most aggressive primary brain tumor in adults. The mechanisms that confer GBM cells their invasive behavior are poorly understood. The electroneutral Na+ -K+ -2Cl- co-transporter 1 (NKCC1) is an important cell volume regulator that participates in cell migration. We have shown that inhibition of NKCC1 in GBM cells leads to decreased cell migration, in vitro and in vivo. We now report on the role of NKCC1 on cytoskeletal dynamics. We show that GBM cells display a significant decrease in F-actin content upon NKCC1 knockdown (NKCC1-KD)...
July 2017: EBioMedicine
Rishov Goswami, Michael Merth, Shweta Sharma, Mazen O Alharbi, Helim Aranda-Espinoza, Xiaoping Zhu, Shaik O Rahaman
Cardiovascular disease is the number one cause of death in United States, and atherosclerosis, a chronic inflammatory arterial disease, is the most dominant underlying pathology. Macrophages are thought to orchestrate atherosclerosis by generating lipid-laden foam cells and by secreting inflammatory mediators. Emerging data support a role for a mechanical factor, e.g., matrix stiffness, in regulation of macrophage function, vascular elasticity, and atherogenesis. However, the identity of the plasma membrane mechanosensor and the mechanisms by which pro-atherogenic signals are transduced/maintained are unknown...
June 8, 2017: Free Radical Biology & Medicine
Gunja K Pathak, Hannah Ornstein, Helim Aranda-Espinoza, Amy J Karlsson, Sameer B Shah
Axons in the peripheral nervous system respond to injury by activating retrograde injury signaling (RIS) pathways, which promote local axonal protein synthesis (LPS) and neuronal regeneration. RIS is also initiated following injury of neurons in the central nervous system (CNS). However, regulation of the localization of axonal mRNA required for LPS is not well understood. We used a hippocampal explant system to probe the regulation of axonal levels of RIS-associated transcripts following axonal injury. Axonal levels of importin β 1 and RanBP1 were elevated biphasically at 1 and 24 hrs after axotomy...
2016: Neural Plasticity
Serajus Salaheen, Ekta Jaiswal, Jungsoo Joo, Mengfei Peng, Ryan Ho, Danielle OConnor, Katrina Adlerz, Jose Helim Aranda-Espinoza, Debabrata Biswas
The aim of this study was to evaluate the phenotypic and genotypic properties of Salmonella enterica serovar Typhimurium (ST) in the presence of lethal and sublethal concentrations (SLC2LOG) of blackberry (Rubus fruticosus) and blueberry (Vaccinium corymbosum) pomace extracts. Antimicrobial susceptibility, physicochemical properties, motility, biofilm formation ability, virulence gene expression patterns, and the ability of ST to colonize in chick cecum were evaluated in the presence of these bioactive extracts...
November 21, 2016: International Journal of Food Microbiology
Katrina M Adlerz, Helim Aranda-Espinoza, Heather N Hayenga
Macrophages play a key role in atherosclerosis, cancer, and in the response to implanted medical devices. In each of these situations, the mechanical environment of a macrophage can vary from soft to stiff. However, how stiffness affects macrophage behavior remains uncertain. Using substrates of varying stiffness, we show macrophage phenotype and function depends on substrate stiffness. Notably, the cell area increases slightly from a sphere after 18 h on substrates mimicking healthy arterial stiffness (1-5 kPa), whereas macrophages on stiffer substrates (280 kPa-70 GPa) increased in area by nearly eight-fold...
May 2016: European Biophysics Journal: EBJ
Susan M Hamilla, Kimberly M Stroka, Helim Aranda-Espinoza
Metastasis is accountable for 90% of cancer deaths. During metastasis, tumor cells break away from the primary tumor, enter the blood and the lymph vessels, and use them as highways to travel to distant sites in the body to form secondary tumors. Cancer cell migration through the endothelium and into the basement membrane represents a critical step in the metastatic cascade, yet it is not well understood. This process is well characterized for immune cells that routinely transmigrate through the endothelium to sites of infection, inflammation, or injury...
2014: PloS One
Gunja K Pathak, Helim Aranda-Espinoza, Sameer B Shah
BACKGROUND: Studies of neuronal regeneration require examination of axons independently of their cell bodies. Several effective strategies have been deployed to compartmentalize long axons of the peripheral nervous system (PNS). However, current strategies to compartmentalize axons of the central nervous system (CNS) may be limited by physical damage to cells during tissue dissociation or slicing, perturbation of three-dimensional tissue architecture, or insufficient axonal tissue for biological analysis...
July 30, 2014: Journal of Neuroscience Methods
Carlos Luna, Laura Detrick, Sameer B Shah, Avis H Cohen, Helim Aranda-Espinoza
During spinal cord injury, nerves suffer a strain beyond their physiological limits which damages and disrupts their structure. Research has been done to measure the modulus of the spinal cord and surrounding tissue; however the relationship between strain and spinal cord fibers is still unclear. In this work, our objective is to measure the stress-strain response of the spinal cord in vivo and in vitro and model this response as a function of the number of fibers. We used the larvae lamprey (Petromyzon Marinus), a model for spinal cord regeneration and animal locomotion...
September 3, 2013: Journal of Biomechanics
Kimberly M Stroka, Heather N Hayenga, Helim Aranda-Espinoza
Transmigration through the endothelium is a key step in the immune response. In our recent work, the mechanical properties of the subendothelial matrix and biophysical state of the endothelium have been identified as key modulators of leukocyte trans-endothelial migration. Here, we demonstrated that neutrophil contractile forces and cytoskeletal dynamics also play an active biophysical role during transmigration through endothelial cell-cell junctions. Using our previously-established model for leukocyte transmigration, we first discovered that >93% of human neutrophils preferentially exploit the paracellular mode of transmigration in our in vitro model, and that is independent of subendothelial matrix stiffness...
2013: PloS One
Lina K Blusch, Yasmin Hemberger, Kevin Pröpper, Birger Dittrich, Franziska Witterauf, Michael John, Gerhard Bringmann, Christian Brückner, Franc Meyer
The 3+3-type synthesis of a pyrazole-based expanded porphyrin 22 H4, a hexaphyrin analogue named Siamese-twin porphyrin, and its homobimetallic diamagnetic nickel(II) and paramagnetic copper(II) complexes, 22 Ni2 and 22 Cu2, are described. The structure of the macrocycle composed of four pyrroles and two pyrazoles all linked by single carbon atoms, can be interpreted as two conjoined porphyrin-like subunits, with the two opposing pyrazoles acting as the fusion points. Variable-temperature 1D and 2D NMR spectroscopic analyses suggested a conformationally flexible structure for 22 H4...
May 3, 2013: Chemistry: a European Journal
Kimberly M Stroka, Janina A Vaitkus, Helim Aranda-Espinoza
The immune response triggers a complicated sequence of events, one of which is release of the cytokine tumor necrosis factor-α (TNF-α) from stromal cells, for example monocytes and macrophages. In this work we investigated the biophysical effects of TNF-α on endothelial cells (ECs), including changes in cell morphology, biomechanics, migration, and cytoskeletal dynamics. We found that TNF-α induces a wide distribution of cell area and aspect ratio, with these properties increasing on average during treatment...
November 2012: European Biophysics Journal: EBJ
Kimberly M Stroka, Irena Levitan, Helim Aranda-Espinoza
Elevated levels of oxLDL in the bloodstream and increased vasculature stiffness are both associated with cardiovascular disease in patients. However, it is not known how oxLDL and subendothelial matrix stiffness together regulate an immune response. Here, we used an in vitro model of the vascular endothelium to explore the combined effects of oxLDL and subendothelial matrix stiffening on neutrophil transmigration. We prepared fibronectin-coated polyacrylamide gels of varying stiffness and plated human umbilical vein endothelial cells (ECs) onto the gels...
June 26, 2012: Journal of Biomechanics
Anu Puri, Hyunbum Jang, Amichai Yavlovich, M Athar Masood, Timothy D Veenstra, Carlos Luna, Helim Aranda-Espinoza, Ruth Nussinov, Robert Blumenthal
Photopolymerizable phospholipid DC(8,9)PC (1,2-bis-(tricosa-10,12-diynoyl)-sn-glycero-3-phosphocholine) exhibits unique assembly characteristics in the lipid bilayer. Because of the presence of the diacetylene groups, DC(8,9)PC undergoes polymerization upon UV (254 nm) exposure and assumes chromogenic properties. DC(8,9)PC photopolymerization in gel-phase matrix lipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monitored by UV-vis absorption spectroscopy occurred within 2 min after UV treatment, whereas no spectral shifts were observed when DC(8,9)PC was incorporated into liquid-phase matrix 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)...
December 20, 2011: Langmuir: the ACS Journal of Surfaces and Colloids
Kimberly M Stroka, Helim Aranda-Espinoza
A vast amount of work has been dedicated to the effects of shear flow and cytokines on leukocyte transmigration. However, no studies have explored the effects of substrate stiffness on transmigration. Here, we investigated important aspects of endothelial cell contraction-mediated neutrophil transmigration using an in vitro model of the vascular endothelium. We modeled blood vessels of varying mechanical properties using fibronectin-coated polyacrylamide gels of varying physiologic stiffness, plated with human umbilical vein endothelial cell (HUVEC) monolayers, which were activated with tumor necrosis factor-α...
August 11, 2011: Blood
Christian Brückner, Daniel C G Götz, Simon P Fox, Claudia Ryppa, Jason R McCarthy, Torsten Bruhn, Joshua Akhigbe, Subhadeep Banerjee, Pedro Daddario, Heather W Daniell, Matthias Zeller, Ross W Boyle, Gerhard Bringmann
The synthesis and chiral resolution of free-base and Ni(II) complexes of a number of derivatives of meso-tetraphenylmorpholinochlorins, with and without direct β-carbon-to-o-phenyl linkages to the flanking phenyl groups, is described. The morpholinochlorins, a class of stable chlorin analogues, were synthesized in two to three steps from meso-tetraphenylporphyrin. The conformations and the relative stereostructures of a variety of free-base and Ni(II) complexes of these morpholinochlorins were elucidated by X-ray diffractometry...
June 8, 2011: Journal of the American Chemical Society
Leann L Norman, Ratna J Oetama, Micah Dembo, F Byfield, Daniel A Hammer, Irena Levitan, Helim Aranda-Espinoza
Cellular cholesterol is a critical component of the plasma membrane, and plays a key role in determining the physical properties of the lipid bilayer, such as elasticity, viscosity, and permeability. Surprisingly, it has been shown that cholesterol depletion increases cell stiffness, not due to plasma membrane stiffening, but rather, due to the interaction between the actin cytoskeleton and the plasma membrane. This indicates that traction stresses of the acto-myosin complex likely increase during cholesterol depletion...
June 1, 2010: Cellular and Molecular Bioengineering
Carlos Luna, Kimberly M Stroka, Harry Bermudez, Helim Aranda-Espinoza
In this work we obtain the thermodynamic properties of mixed (1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine) PC and (1-stearoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (sodium salt)) PS monolayers. Measurements of compressibility (isotherms, bulk modulus, and excess area per molecule) and surface potential show that the properties of monolayers at the air-water interface depend on the concentration of ions (Na(+) and K(+)) and the proportion of PS in the mixture. The dependence on PS arises because the molecule is originally bound to a Na(+) counterion; by increasing the concentration of ions the entropy changes, creating a favorable system for the bound counterions of PS to join the bulk, leaving a negatively charged molecule...
July 1, 2011: Colloids and Surfaces. B, Biointerfaces
Kimberly M Stroka, Helim Aranda-Espinoza
Biological processes such as atherogenesis, wound healing, cancer cell metastasis, and immune cell transmigration rely on a delicate balance between Cell-Cell and cell-substrate adhesion. Cell mechanics have been shown to depend on substrate factors such as stiffness and ligand presentation, while the effects of Cell-Cell interactions on the mechanical properties of cells has received little attention. Here, we use atomic force microscopy to measure the Young's modulus of live human umbilical vein endothelial cells (HUVECs)...
March 1, 2011: Cellular and Molecular Bioengineering
Leann Norman, Kheya Sengupta, Helim Aranda-Espinoza
Cell spreading is a critical component of numerous physiological phenomena including cancer metastasis, embryonic development, and mitosis. We have previously illustrated that cellular blebs appear after abrupt cell-substrate detachment and play a critical role in regulating membrane tension; however, the dynamics of bleb-substrate interactions during spreading remains unclear. Here we explore the role of blebs during endothelial cell spreading using chemical and osmotic modifications to either induce or inhibit bleb formation...
January 2011: European Journal of Cell Biology
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