International Journal of Cell Biology The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Measured Effects of Wnt3a on Proliferation of HEK293T Cells Depend on the Applied Assay Tue, 22 Dec 2015 11:12:14 +0000 The Wnt signaling pathway has been associated with many essential cell processes. This study aims to examine the effects of Wnt signaling on proliferation of cultured HEK293T cells. Cells were incubated with Wnt3a, and the activation of the Wnt pathway was followed by analysis of the level of the β-catenin protein and of the expression levels of the target genes MYC and CCND1. The level of β-catenin protein increased up to fourfold. While the mRNA levels of c-Myc and cyclin D1 increased slightly, the protein levels increased up to a factor of 1.5. Remarkably, MTT and BrdU assays showed different results when measuring the proliferation rate of Wnt3a stimulated HEK293T cells. In the BrdU assays an increase of the proliferation rate could be detected, which correlated to the applied Wnt3a concentration. Oppositely, this correlation could not be shown in the MTT assays. The MTT results, which are based on the mitochondrial activity, were confirmed by analysis of the succinate dehydrogenase complex by immunofluorescence and by western blotting. Taken together, our study shows that Wnt3a activates proliferation of HEK293 cells. These effects can be detected by measuring DNA synthesis rather than by measuring changes of mitochondrial activity. Patricia Reischmann, Johanna Fiebeck, Nadine von der Weiden, and Oliver Müller Copyright © 2015 Patricia Reischmann et al. All rights reserved. Integration of Mitochondrial Targeting for Molecular Cancer Therapeutics Wed, 02 Dec 2015 11:24:55 +0000 Mitochondrial metabolism greatly influences cancer cell survival, invasion, metastasis, and resistance to many anticancer drugs. Furthermore, molecular-targeted therapies (e.g., oncogenic kinase inhibitors) create a dependence of surviving cells on mitochondrial metabolism. For these reasons, inhibition of mitochondrial metabolism represents promising therapeutic pathways in cancer. This review provides an overview of mitochondrial metabolism in cancer and discusses the limitations of mitochondrial inhibition for cancer treatment. Finally, we present preclinical evidence that mitochondrial inhibition could be associated with oncogenic “drivers” inhibitors, which may lead to innovative drug combinations for improving the efficacy of molecular-targeted therapy. Philippe Marchetti, Pierre Guerreschi, Laurent Mortier, and Jerome Kluza Copyright © 2015 Philippe Marchetti et al. All rights reserved. Effects of Activating Mutations on EGFR Cellular Protein Turnover and Amino Acid Recycling Determined Using SILAC Mass Spectrometry Tue, 24 Nov 2015 11:56:06 +0000 Rapid mutations of proteins that are targeted in cancer therapy often lead to drug resistance. Often, the mutation directly affects a drug’s binding site, effectively blocking binding of the drug, but these mutations can have other effects such as changing the protein turnover half-life. Utilizing SILAC MS, we measured the cellular turnover rates of an important non-small cell lung cancer target, epidermal growth factor receptor (EGFR). Wild-type (WT) EGFR, EGFR with a single activating mutant (Del 746–750 or L858R), and the drug-resistant double mutant (L858R/T790M) EGFR were analyzed. In non-small cell lung cancer cell lines, EGFR turnover rates ranged from 28 hours in A431 cells (WT) to 7.5 hours in the PC-9 cells (Del 746–750 mutant). The measurement of EGFR turnover rate in PC-9 cells dosed with irreversible inhibitors has additional complexity due to inhibitor effects on cell viability and results were reported as a range. Finally, essential amino acid recycling (K and R) was measured in different cell lines. The recycling was different in each cell line, but the overall inclusion of the effect of amino acid recycling on calculating EGFR turnover rates resulted in a 10–20% reduction in rates. Michael J. Greig, Sherry Niessen, Scott L. Weinrich, Jun Li Feng, Manli Shi, and Ted O. Johnson Copyright © 2015 Michael J. Greig et al. All rights reserved. A Simple and Efficient Method for Preparing Cell Slides and Staining without Using Cytocentrifuge and Cytoclips Tue, 17 Nov 2015 11:17:14 +0000 Cell staining is a necessary and useful technique for visualizing cell morphology and structure under a microscope. This technique has been used in many areas such as cytology, hematology, oncology, histology, virology, serology, microbiology, cell biology, and immunochemistry. One of the key pieces of equipment for preparing a slide for cell staining is cytology centrifuge (cytocentrifuge) such as cytospin. However, many small labs do not have this expensive equipment and its accessory, cytoclips (also expensive relatively), which makes them difficult to study cell cytology. Here we present an alternative method for preparing a slide and cell staining in the absence of a cytocentrifuge (and cytoclips). This method is based on the principle that a regular cell centrifuge can be used to concentrate cells harvested from cell culture and then deposit the concentrated cell suspension to a slide evenly by using a cell spreader, followed by cell staining. The method presented is simple, rapid, economic, and efficient. This method may also avoid a possible change in cell morphology induced by cytocentrifuge. Xiaotang Hu, Verronika Laguerre, Daniel Packert, Alice Nakasone, and Lynn Moscinski Copyright © 2015 Xiaotang Hu et al. All rights reserved. Advances in Hyaluronan Biology: Signaling, Regulation, and Disease Mechanisms Sun, 13 Sep 2015 05:56:06 +0000 Melanie A. Simpson, Carol de la Motte, Larry S. Sherman, and Paul H. Weigel Copyright © 2015 Melanie A. Simpson et al. All rights reserved. Regulatory T Cells Resist Cyclosporine-Induced Cell Death via CD44-Mediated Signaling Pathways Thu, 10 Sep 2015 13:31:48 +0000 Cyclosporine A (CSA) is an immunosuppressive agent that specifically targets T cells and also increases the percentage of pro-tolerogenic CD4+Foxp3+ regulatory T cells (Treg) through unknown mechanisms. We previously reported that CD44, a receptor for the extracellular matrix glycosaminoglycan hyaluronan (HA), promotes Treg stability in IL-2-low environments. Here, we asked whether CD44 signaling also promotes Treg resistance to CSA. We found that CD44 cross-linking promoted Foxp3 expression and Treg viability in the setting of CSA treatment. This effect was IL-2 independent but could be suppressed using sc-355979, an inhibitor of Stat5-phosphorylation. Moreover, we found that inhibition of HA synthesis impairs Treg homeostasis but that this effect could be overcome with exogenous IL-2 or CD44-cross-linking. Together, these data support a model whereby CD44 cross-linking by HA promotes IL-2-independent Foxp3 expression and Treg survival in the face of CSA. Shannon M. Ruppert, Ben A. Falk, S. Alice Long, and Paul L. Bollyky Copyright © 2015 Shannon M. Ruppert et al. All rights reserved. High Sensitivity Method to Estimate Distribution of Hyaluronan Molecular Sizes in Small Biological Samples Using Gas-Phase Electrophoretic Mobility Molecular Analysis Thu, 10 Sep 2015 13:22:48 +0000 Hyaluronan is a negatively charged polydisperse polysaccharide where both its size and tissue concentration play an important role in many physiological and pathological processes. The various functions of hyaluronan depend on its molecular size. Up to now, it has been difficult to study the role of hyaluronan in diseases with pathological changes in the extracellular matrix where availability is low or tissue samples are small. Difficulty to obtain large enough biopsies from human diseased tissue or tissue from animal models has also restricted the study of hyaluronan. In this paper, we demonstrate that gas-phase electrophoretic molecular mobility analyzer (GEMMA) can be used to estimate the distribution of hyaluronan molecular sizes in biological samples with a limited amount of hyaluronan. The low detection level of the GEMMA method allows for estimation of hyaluronan molecular sizes from different parts of small organs. Hence, the GEMMA method opens opportunity to attain a profile over the distribution of hyaluronan molecular sizes and estimate changes caused by disease or experimental conditions that has not been possible to obtain before. Lan Do, Christen P. Dahl, Susanne Kerje, Peter Hansell, Stellan Mörner, Ulla Lindqvist, Anna Engström-Laurent, Göran Larsson, and Urban Hellman Copyright © 2015 Lan Do et al. All rights reserved. Correlative Light and Electron Microscopy Reveals the HAS3-Induced Dorsal Plasma Membrane Ruffles Thu, 10 Sep 2015 13:19:33 +0000 Hyaluronan is a linear sugar polymer synthesized by three isoforms of hyaluronan synthases (HAS1, 2, and 3) that forms a hydrated scaffold around cells and is an essential component of the extracellular matrix. The morphological changes of cells induced by active hyaluronan synthesis are well recognized but not studied in detail with high resolution before. We have previously found that overexpression of HAS3 induces growth of long plasma membrane protrusions that act as platforms for hyaluronan synthesis. The study of these thin and fragile protrusions is challenging, and they are difficult to preserve by fixation unless they are adherent to the substrate. Thus their structure and regulation are still partly unclear despite careful imaging with different microscopic methods in several cell types. In this study, correlative light and electron microscopy (CLEM) was utilized to correlate the GFP-HAS3 signal and the surface ultrastructure of cells in order to study in detail the morphological changes induced by HAS3 overexpression. Surprisingly, this method revealed that GFP-HAS3 not only localizes to ruffles but in fact induces dorsal ruffle formation. Dorsal ruffles regulate diverse cellular functions, such as motility, regulation of glucose metabolism, spreading, adhesion, and matrix degradation, the same functions driven by active hyaluronan synthesis. Kirsi Rilla and Arto Koistinen Copyright © 2015 Kirsi Rilla and Arto Koistinen. All rights reserved. Regulated Hyaluronan Synthesis by Vascular Cells Thu, 10 Sep 2015 13:18:33 +0000 Cellular microenvironment plays a critical role in several pathologies including atherosclerosis. Hyaluronan (HA) content often reflects the progression of this disease in promoting vessel thickening and cell migration. HA synthesis is regulated by several factors, including the phosphorylation of HA synthase 2 (HAS2) and other covalent modifications including ubiquitination and O-GlcNAcylation. Substrate availability is important in HA synthesis control. Specific drugs reducing the UDP precursors are able to reduce HA synthesis whereas the hexosamine biosynthetic pathway (HBP) increases the concentration of HA precursor UDP-N-acetylglucosamine (UDP-GlcNAc) leading to an increase of HA synthesis. The flux through the HBP in the regulation of HA biosynthesis in human aortic vascular smooth muscle cells (VSMCs) was reported as a critical aspect. In fact, inhibiting O-GlcNAcylation reduced HA production whereas increased O-GlcNAcylation augmented HA secretion. Additionally, O-GlcNAcylation regulates HAS2 gene expression resulting in accumulation of its mRNA after induction of O-GlcNAcylation with glucosamine treatments. The oxidized LDLs, the most common molecules related to atherosclerosis outcome and progression, are also able to induce a strong HA synthesis when they are in contact with vascular cells. In this review, we present recent described mechanisms involved in HA synthesis regulation and their role in atherosclerosis outcome and development. Manuela Viola, Evgenia Karousou, Maria Luisa D’Angelo, Ilaria Caon, Giancarlo De Luca, Alberto Passi, and Davide Vigetti Copyright © 2015 Manuela Viola et al. All rights reserved. Extracellular Vesicles from Caveolin-Enriched Microdomains Regulate Hyaluronan-Mediated Sustained Vascular Integrity Thu, 10 Sep 2015 13:06:28 +0000 Defects in vascular integrity are an initiating factor in several disease processes. We have previously reported that high molecular weight hyaluronan (HMW-HA), a major glycosaminoglycan in the body, promotes rapid signal transduction in human pulmonary microvascular endothelial cells (HPMVEC) leading to barrier enhancement. In contrast, low molecular weight hyaluronan (LMW-HA), produced in disease states by hyaluronidases and reactive oxygen species (ROS), induces HPMVEC barrier disruption. However, the mechanism(s) of sustained barrier regulation by HA are poorly defined. Our results indicate that long-term (6–24 hours) exposure of HMW-HA induced release of a novel type of extracellular vesicle from HLMVEC called enlargeosomes (characterized by AHNAK expression) while LMW-HA long-term exposure promoted release of exosomes (characterized by CD9, CD63, and CD81 expression). These effects were blocked by inhibiting caveolin-enriched microdomain (CEM) formation. Further, inhibiting enlargeosome release by annexin II siRNA attenuated the sustained barrier enhancing effects of HMW-HA. Finally, exposure of isolated enlargeosomes to HPMVEC monolayers generated barrier enhancement while exosomes led to barrier disruption. Taken together, these results suggest that differential release of extracellular vesicles from CEM modulate the sustained HPMVEC barrier regulation by HMW-HA and LMW-HA. HMW-HA-induced specialized enlargeosomes can be a potential therapeutic strategy for diseases involving impaired vascular integrity. Tamara Mirzapoiazova, Frances E. Lennon, Bolot Mambetsariev, Michael Allen, Jacob Riehm, Valeriy A. Poroyko, and Patrick A. Singleton Copyright © 2015 Tamara Mirzapoiazova et al. All rights reserved. The Rise and Fall of Hyaluronan in Respiratory Diseases Thu, 10 Sep 2015 12:21:45 +0000 In normal airways, hyaluronan (HA) matrices are primarily located within the airway submucosa, pulmonary vasculature walls, and, to a lesser extent, the alveoli. Following pulmonary injury, elevated levels of HA matrices accumulate in these regions, and in respiratory secretions, correlating with the extent of injury. Animal models have provided important insight into the role of HA in the onset of pulmonary injury and repair, generally indicating that the induction of HA synthesis is an early event typically preceding fibrosis. The HA that accumulates in inflamed airways is of a high molecular weight (>1600 kDa) but can be broken down into smaller fragments (<150 kDa) by inflammatory and disease-related mechanisms that have profound effects on HA pathobiology. During inflammation in the airways, HA is often covalently modified with heavy chains from inter-alpha-inhibitor via the enzyme tumor-necrosis-factor-stimulated-gene-6 (TSG-6) and this modification promotes the interaction of leukocytes with HA matrices at sites of inflammation. The clearance of HA and its return to normal levels is essential for the proper resolution of inflammation. These data portray HA matrices as an important component of normal airway physiology and illustrate its integral roles during tissue injury and repair among a variety of respiratory diseases. Mark E. Lauer, Raed A. Dweik, Stavros Garantziotis, and Mark A. Aronica Copyright © 2015 Mark E. Lauer et al. All rights reserved. Size Matters: Molecular Weight Specificity of Hyaluronan Effects in Cell Biology Thu, 10 Sep 2015 12:18:21 +0000 Hyaluronan signaling properties are unique among other biologically active molecules, that they are apparently not influenced by postsynthetic molecular modification, but by hyaluronan fragment size. This review summarizes the current knowledge about the generation of hyaluronan fragments of different size and size-dependent differences in hyaluronan signaling as well as their downstream biological effects. Jaime M. Cyphert, Carol S. Trempus, and Stavros Garantziotis Copyright © 2015 Jaime M. Cyphert et al. All rights reserved. Hyaluronan Synthase 3 Null Mice Exhibit Decreased Intestinal Inflammation and Tissue Damage in the DSS-Induced Colitis Model Thu, 10 Sep 2015 12:12:26 +0000 Hyaluronan (HA) overproduction is a hallmark of multiple inflammatory diseases, including inflammatory bowel disease (IBD). Hyaluronan can act as a leukocyte recruitment molecule and in the most common mouse model of intestinal inflammation, the chemically induced dextran sodium sulfate (DSS) experimental colitis model, we previously determined that changes in colon distribution of HA occur before inflammation. Therefore, we hypothesized that, during a pathologic challenge, HA promotes inflammation. In this study, we tested the progression of inflammation in mice null for the hyaluronan synthase genes (HAS1, HAS3, or both HAS1 and HAS3) in the DSS-colitis model. Our data demonstrate that both the HAS1/HAS3 double and the HAS3 null mice are protected from colitis, compared to wild-type and HAS1 null mice, as determined by measurement of weight loss, disease activity, serum IL-6 levels, histologic scoring, and immunohistochemistry. Most notable is the dramatic increase in submucosal microvasculature, hyaluronan deposition, and leukocyte infiltration in the inflamed colon tissue of wild-type and HAS1 null mice. Our data suggest, HAS3 plays a crucial role in driving gut inflammation. Developing a temporary targeted therapeutic intervention of HAS3 expression or function in the microcirculation may emerge as a desirable strategy toward tempering colitis in patients undergoing flares of IBD. Sean P. Kessler, Dana R. Obery, and Carol de la Motte Copyright © 2015 Sean P. Kessler et al. All rights reserved. Carboxymethyl Hyaluronan-Stabilized Nanoparticles for Anticancer Drug Delivery Thu, 10 Sep 2015 11:57:28 +0000 Carboxymethyl hyaluronic acid (CMHA) is a semisynthetic derivative of HA that is recognized by HA binding proteins but contains an additional carboxylic acid on some of the 6-hydroxyl groups of the N-acetyl glucosamine sugar units. These studies tested the ability of CMHA to stabilize the formation of calcium phosphate nanoparticles and evaluated their potential to target therapy resistant, CD44+/CD24−/low human breast cancer cells (BT-474EMT). CMHA stabilized particles (nCaPCMHA) were loaded with the chemotherapy drug cis-diamminedichloroplatinum(II) (CDDP) to form nCaPCMHACDDP. nCaPCMHACDDP was determined to be poorly crystalline hydroxyapatite, 200 nm in diameter with a −43 mV zeta potential. nCaPCMHACDDP exhibited a two-day burst release of CDDP that tapered resulting in 86% release by 7 days. Surface plasmon resonance showed that nCaPCMHACDDP binds to CD44, but less effectively than CMHA or hyaluronan. nCaP was taken up by CD44+/CD24− BT-474EMT breast cancer cells within 18 hours. nCaPCMHACDDP was as cytotoxic as free CDDP against the BT-474EMT cells. Subcutaneous BT-474EMT tumors were more reproducibly inhibited by a near tumor dose of 2.8 mg/kg CDDP than a 7 mg/kg dose nCaPCMHACDDP. This was likely due to a lack of distribution of nCaPCMHACDDP throughout the dense tumor tissue that limited drug diffusion. Jessica L. Woodman, Min Sung Suh, Jianxing Zhang, Yuvabharath Kondaveeti, Diane J. Burgess, Bruce A. White, Glenn D. Prestwich, and Liisa T. Kuhn Copyright © 2015 Jessica L. Woodman et al. All rights reserved. Utilization of Glycosaminoglycans/Proteoglycans as Carriers for Targeted Therapy Delivery Thu, 10 Sep 2015 11:49:18 +0000 The outcome of patients with cancer has improved significantly in the past decade with the incorporation of drugs targeting cell surface adhesive receptors, receptor tyrosine kinases, and modulation of several molecules of extracellular matrices (ECMs), the complex composite of collagens, glycoproteins, proteoglycans, and glycosaminoglycans that dictates tissue architecture. Cancer tissue invasive processes progress by various oncogenic strategies, including interfering with ECM molecules and their interactions with invasive cells. In this review, we describe how the ECM components, proteoglycans and glycosaminoglycans, influence tumor cell signaling. In particular this review describes how the glycosaminoglycan hyaluronan (HA) and its major receptor CD44 impact invasive behavior of tumor cells, and provides useful insight when designing new therapeutic strategies in the treatment of cancer. Suniti Misra, Vincent C. Hascall, Ilia Atanelishvili, Ricardo Moreno Rodriguez, Roger R. Markwald, and Shibnath Ghatak Copyright © 2015 Suniti Misra et al. All rights reserved. Selective Activation of Cancer Stem Cells by Size-Specific Hyaluronan in Head and Neck Cancer Thu, 10 Sep 2015 11:27:27 +0000 We determined that human head and neck cancer cells (HSC-3 cell line) contain a subpopulation displaying cancer stem cell (CSC) properties and are very tumorigenic. Specifically, we investigated whether different sizes of hyaluronan (HA) (e.g., 5 kDa, 20 kDa, 200 kDa, or 700 kDa-HA-sizes) play a role in regulating these CSCs. First, we observed that 200 kDa-HA (but not other sizes of HA) preferentially induces certain stem cell marker expression resulting in self-renewal and clonal formation of these cells. Further analyses indicate that 200 kDa-HA selectively stimulates the expression of a panel of microRNAs (most noticeably miR-10b) in these CSCs. Survival protein (cIAP-1) expression was also stimulated by 200 kDa-HA in these CSCs leading to cisplatin resistance. Furthermore, our results indicate that the anti-miR-10 inhibitor not only decreases survival protein expression, but also increases chemosensitivity of the 200 kDa-HA-treated CSCs. These findings strongly support the contention that 200 kDa-HA plays a pivotal role in miR-10 production leading to survival protein upregulation and chemoresistance in CSCs. Together, our findings suggest that selective activation of oncogenic signaling by certain sizes of HA (e.g., 200 kDa-HA) may be instrumental in the formation of CSC functions leading to tumor cell survival and chemoresistance in head and neck cancer progression. Marisa Shiina and Lilly Y. W. Bourguignon Copyright © 2015 Marisa Shiina and Lilly Y. W. Bourguignon. All rights reserved. Roles of Proteoglycans and Glycosaminoglycans in Wound Healing and Fibrosis Thu, 10 Sep 2015 11:25:11 +0000 A wound is a type of injury that damages living tissues. In this review, we will be referring mainly to healing responses in the organs including skin and the lungs. Fibrosis is a process of dysregulated extracellular matrix (ECM) production that leads to a dense and functionally abnormal connective tissue compartment (dermis). In tissues such as the skin, the repair of the dermis after wounding requires not only the fibroblasts that produce the ECM molecules, but also the overlying epithelial layer (keratinocytes), the endothelial cells, and smooth muscle cells of the blood vessel and white blood cells such as neutrophils and macrophages, which together orchestrate the cytokine-mediated signaling and paracrine interactions that are required to regulate the proper extent and timing of the repair process. This review will focus on the importance of extracellular molecules in the microenvironment, primarily the proteoglycans and glycosaminoglycan hyaluronan, and their roles in wound healing. First, we will briefly summarize the physiological, cellular, and biochemical elements of wound healing, including the importance of cytokine cross-talk between cell types. Second, we will discuss the role of proteoglycans and hyaluronan in regulating these processes. Finally, approaches that utilize these concepts as potential therapies for fibrosis are discussed. Shibnath Ghatak, Edward V. Maytin, Judith A. Mack, Vincent C. Hascall, Ilia Atanelishvili, Ricardo Moreno Rodriguez, Roger R. Markwald, and Suniti Misra Copyright © 2015 Shibnath Ghatak et al. All rights reserved. Hyaluronan Synthase: The Mechanism of Initiation at the Reducing End and a Pendulum Model for Polysaccharide Translocation to the Cell Exterior Thu, 10 Sep 2015 10:57:08 +0000 Hyaluronan (HA) biosynthesis has been studied for over six decades, but our understanding of the biochemical details of how HA synthase (HAS) assembles HA is still incomplete. Class I family members include mammalian and streptococcal HASs, the focus of this review, which add new intracellular sugar-UDPs at the reducing end of growing hyaluronyl-UDP chains. HA-producing cells typically create extracellular HA coats (capsules) and also secrete HA into the surrounding space. Since HAS contains multiple transmembrane domains and is lipid-dependent, we proposed in 1999 that it creates an intraprotein HAS-lipid pore through which a growing HA-UDP chain is translocated continuously across the cell membrane to the exterior. We review here the evidence for a synthase pore-mediated polysaccharide translocation process and describe a possible mechanism (the Pendulum Model) and potential energy sources to drive this ATP-independent process. HA synthases also synthesize chitin oligosaccharides, which are created by cleavage of novel oligo-chitosyl-UDP products. The synthesis of chitin-UDP oligomers by HAS confirms the reducing end mechanism for sugar addition during HA assembly by streptococcal and mammalian Class I enzymes. These new findings indicate the possibility that HA biosynthesis is initiated by the ability of HAS to use chitin-UDP oligomers as self-primers. Paul H. Weigel Copyright © 2015 Paul H. Weigel. All rights reserved. Hyperglycemia-Induced Changes in Hyaluronan Contribute to Impaired Skin Wound Healing in Diabetes: Review and Perspective Thu, 10 Sep 2015 09:47:45 +0000 Ulcers and chronic wounds are a particularly common problem in diabetics and are associated with hyperglycemia. In this targeted review, we summarize evidence suggesting that defective wound healing in diabetics is causally linked, at least in part, to hyperglycemia-induced changes in the status of hyaluronan (HA) that resides in the pericellular coat (glycocalyx) of endothelial cells of small cutaneous blood vessels. Potential mechanisms through which exposure to high glucose levels causes a loss of the glycocalyx on the endothelium and accelerates the recruitment of leukocytes, creating a proinflammatory environment, are discussed in detail. Hyperglycemia also affects other cells in the immediate perivascular area, including pericytes and smooth muscle cells, through exposure to increased cytokine levels and through glucose elevations in the interstitial fluid. Possible roles of newly recognized, cross-linked forms of HA, and interactions of a major HA receptor (CD44) with cytokine/growth factor receptors during hyperglycemia, are also discussed. Sajina Shakya, Yan Wang, Judith A. Mack, and Edward V. Maytin Copyright © 2015 Sajina Shakya et al. All rights reserved. Hyaluronan Synthesis, Catabolism, and Signaling in Neurodegenerative Diseases Thu, 10 Sep 2015 09:43:36 +0000 The glycosaminoglycan hyaluronan (HA), a component of the extracellular matrix, has been implicated in regulating neural differentiation, survival, proliferation, migration, and cell signaling in the mammalian central nervous system (CNS). HA is found throughout the CNS as a constituent of proteoglycans, especially within perineuronal nets that have been implicated in regulating neuronal activity. HA is also found in the white matter where it is diffusely distributed around astrocytes and oligodendrocytes. Insults to the CNS lead to long-term elevation of HA within damaged tissues, which is linked at least in part to increased transcription of HA synthases. HA accumulation is often accompanied by elevated expression of at least some transmembrane HA receptors including CD44. Hyaluronidases that digest high molecular weight HA into smaller fragments are also elevated following CNS insults and can generate HA digestion products that have unique biological activities. A number of studies, for example, suggest that both the removal of high molecular weight HA and the accumulation of hyaluronidase-generated HA digestion products can impact CNS injuries through mechanisms that include the regulation of progenitor cell differentiation and proliferation. These studies, reviewed here, suggest that targeting HA synthesis, catabolism, and signaling are all potential strategies to promote CNS repair. Larry S. Sherman, Steven Matsumoto, Weiping Su, Taasin Srivastava, and Stephen A. Back Copyright © 2015 Larry S. Sherman et al. All rights reserved. Modulation Effects of Curcumin on Erythrocyte Ion-Transporter Activity Wed, 02 Sep 2015 11:30:12 +0000 Curcumin ((1E,6E)-1,7-Bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), the yellow biphenolic pigment isolated from turmeric (Curcuma longa), has various medicinal benefits through antioxidation, anti-inflammation, cardiovascular protection, immunomodulation, enhancing of the apoptotic process, and antiangiogenic property. We explored the effects of curcumin in vitro (10−5 M to 10−8 M) and in vivo (340 and 170 mg/kg b.w., oral) on Na+/K+ ATPase (NKA), Na+/H+ exchanger (NHE) activity, and membrane lipid hydroperoxides (ROOH) in control and experimental oxidative stress erythrocytes of Wistar rats. As a result, we found that curcumin potently modulated the membrane transporters activity with protecting membrane lipids against hydro-peroxidation in control as well as oxidatively challenged erythrocytes evidenced by stimulation of NKA, downregulation of NHE, and reduction of ROOH in the membrane. The observed results corroborate membrane transporters activity with susceptibility of erythrocyte membrane towards oxidative damage. Results explain the protective mechanism of curcumin against oxidative stress mediated impairment in ions-transporters activity and health beneficial effects. Prabhakar Singh and Syed Ibrahim Rizvi Copyright © 2015 Prabhakar Singh and Syed Ibrahim Rizvi. All rights reserved. Impact of Hybrid and Complex N-Glycans on Cell Surface Targeting of the Endogenous Chloride Cotransporter Slc12a2 Mon, 17 Aug 2015 13:56:41 +0000 The Na+K+2Cl− cotransporter-1 (Slc12a2, NKCC1) is widely distributed and involved in cell volume/ion regulation. Functional NKCC1 locates in the plasma membrane of all cells studied, particularly in the basolateral membrane of most polarized cells. Although the mechanisms involved in plasma membrane sorting of NKCC1 are poorly understood, it is assumed that N-glycosylation is necessary. Here, we characterize expression, N-glycosylation, and distribution of NKCC1 in COS7 cells. We show that ~25% of NKCC1 is complex N-glycosylated whereas the rest of it corresponds to core/high-mannose and hybrid-type N-glycosylated forms. Further, ~10% of NKCC1 reaches the plasma membrane, mostly as core/high-mannose type, whereas ~90% of NKCC1 is distributed in defined intracellular compartments. In addition, inhibition of the first step of N-glycan biosynthesis with tunicamycin decreases total and plasma membrane located NKCC1 resulting in almost undetectable cotransport function. Moreover, inhibition of N-glycan maturation with swainsonine or kifunensine increased core/hybrid-type NKCC1 expression but eliminated plasma membrane complex N-glycosylated NKCC1 and transport function. Together, these results suggest that (i) NKCC1 is delivered to the plasma membrane of COS7 cells independently of its N-glycan nature, (ii) most of NKCC1 in the plasma membrane is core/hybrid-type N-glycosylated, and (iii) the minimal proportion of complex N-glycosylated NKCC1 is functionally active. Richa Singh, Mohammed Mashari Almutairi, Romario Pacheco-Andrade, Mohamed Y. Mahmoud Almiahuob, and Mauricio Di Fulvio Copyright © 2015 Richa Singh et al. All rights reserved. Intermittent Compressive Stress Enhanced Insulin-Like Growth Factor-1 Expression in Human Periodontal Ligament Cells Thu, 28 May 2015 07:40:48 +0000 Mechanical force was shown to promote IGF-1 expression in periodontal ligament both in vitro and in vivo. Though the mechanism of this effect has not yet been proved, here we investigated the molecular mechanism of intermittent mechanical stress on IGF-1 expression. In addition, the role of hypoxia on the intermittent compressive stress on IGF-1 expression was also examined. In this study, human periodontal ligament cells (HPDLs) were stimulated with intermittent mechanical stress for 24 hours. IGF-1 expression was examined by real-time polymerase chain reaction. Chemical inhibitors were used to determine molecular mechanisms of these effects. For hypoxic mimic condition, the CoCl2 supplementation was employed. The results showed that intermittent mechanical stress dramatically increased IGF-1 expression at 24 h. The pretreatment with TGF-β receptor I or TGF-β1 antibody could inhibit the intermittent mechanical stress-induced IGF-1 expression. Moreover, the upregulation of TGF-β1 proteins was detected in intermittent mechanical stress treated group. Correspondingly, the IGF-1 expression was upregulated upon being treated with recombinant human TGF-β1. Further, the hypoxic mimic condition attenuated the intermittent mechanical stress and rhTGF-β1-induced IGF-1 expression. In summary, this study suggests intermittent mechanical stress-induced IGF-1 expression in HPDLs through TGF-β1 and this phenomenon could be inhibited in hypoxic mimic condition. Jittima Pumklin, Jeeranan Manokawinchoke, Kanokporn Bhalang, and Prasit Pavasant Copyright © 2015 Jittima Pumklin et al. All rights reserved. The Role of Hyaluronan in Innate Defense Responses of the Intestine Mon, 30 Mar 2015 08:05:41 +0000 Hyaluronan is an abundant extracellular matrix component prevalent in the vertebrate intestinal tract. Here we discuss what is known about hyaluronan distribution during homeostasis and inflammatory diseases of the gut and discuss ways in which this glycosaminoglycan can participate in regulating innate host defense mechanisms. These natural responses include mechanisms promoting rapid leukocyte recruitment after bacterial challenge/colon tissue damage as well as promoting epithelial defense mechanisms in the intestine. Carol A. de la Motte and Sean P. Kessler Copyright © 2015 Carol A. de la Motte and Sean P. Kessler. All rights reserved. HARE-Mediated Endocytosis of Hyaluronan and Heparin Is Targeted by Different Subsets of Three Endocytic Motifs Wed, 25 Mar 2015 06:59:36 +0000 The hyaluronan (HA) receptor for endocytosis (HARE) is a multifunctional recycling clearance receptor for 14 different ligands, including HA and heparin (Hep), which bind to discrete nonoverlapping sites. Four different functional endocytic motifs (M) in the cytoplasmic domain (CD) target coated pit mediated uptake: (YSYFRI2485 (M1), FQHF2495 (M2), NPLY2519 (M3), and DPF2534 (M4)). We previously found (Pandey et al. J. Biol. Chem. 283, 21453, 2008) that M1, M2, and M3 mediate endocytosis of HA. Here we assessed the ability of HARE variants with a single-motif deletion or containing only a single motif to endocytose HA or Hep. Single-motif deletion variants lacking M1, M3, or M4 (a different subset than involved in HA uptake) showed decreased Hep endocytosis, although M3 was the most active; the remaining redundant motifs did not compensate for loss of other motifs. Surprisingly, a HARE CD variant with only M3 internalized both HA and Hep, whereas variants with either M2 or M4 alone did not endocytose either ligand. Internalization of HA and Hep by HARE CD mutants was dynamin-dependent and was inhibited by hyperosmolarity, confirming clathrin-mediated endocytosis. The results indicate a complicated relationship among multiple CD motifs that target coated pit uptake and a more fundamental role for motif M3. Madhu S. Pandey, Edward N. Harris, and Paul H. Weigel Copyright © 2015 Madhu S. Pandey et al. All rights reserved. Effect of Serum and Oxygen Concentration on Gene Expression and Secretion of Paracrine Factors by Mesenchymal Stem Cells Mon, 29 Dec 2014 00:10:21 +0000 Mesenchymal stem cells (MSC) secrete paracrine factors that may exert a protective effect on the heart after coronary artery occlusion. This study was done to determine the effect of hypoxia and serum levels on the mRNA expression and secretion of paracrine factors. Mouse bone marrow MSC were cultured with 5% or 20% serum and in either normoxic (21% O2) or hypoxic (1% O2) conditions. Expression of mRNA for vascular endothelial growth factor (VEGF), monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), MIP-1β, and matrix metalloproteinase-2 (MMP-2) was determined by RT-qPCR. Secretion into the culture media was determined by ELISA. Hypoxia caused a reduction in gene expression for MCP-1 and an increase for VEGF (5% serum), MIP-1α, MIP-1β, and MMP-2. Serum reduction lowered gene expression for VEGF (normoxia), MCP-1 (hypoxia), MIP-1α (hypoxia), MIP-1β (hypoxia), and MMP-2 (hypoxia) and increased gene expression for MMP-2 (normoxia). The level of secretion of these factors into the media generally paralleled gene expression with some exceptions. These data demonstrate that serum and oxygen levels have a significant effect on the gene expression and secretion of paracrine factors by MSC which will affect how MSC interact in vivo during myocardial ischemia. Patrick Page, Joshua DeJong, Alaina Bandstra, and Robert A. Boomsma Copyright © 2014 Patrick Page et al. All rights reserved. CXCL12 Modulates Prostate Cancer Cell Adhesion by Altering the Levels or Activities of β1-Containing Integrins Mon, 15 Dec 2014 07:38:05 +0000 The mechanisms by which prostate cancer (PCa) cell adhesion and migration are controlled during metastasis are not well understood. Here, we studied the effect of CXCL12 in PCa cell adhesion and spreading in DU145 and PC3 cell lines using as substrates collagen I, fibronectin (FN), and their recombinant fragments. CXCL12 treatment increased β1 integrin-dependent PC3 cell adhesion on FN which correlated with increased focal adhesion kinase activation. However neither α5β1 nor α4β1 subunits were involved in this adhesion. By contrast, CXCL12 decreased DU145 adhesion and spreading on FN by downregulating α5 and β1 integrin expression. To demonstrate the clinical relevance of CXCL12 in PCa, we measured CXCL12 levels in plasma by using ELISA and found that the chemokine is elevated in PCa patients when compared to controls. The high concentration of CXCL12 in patients suffering from PCa in comparison to those with benign disease or healthy individuals implicates CXCL12 as a potential biomarker for PCa. In addition these data show that CXCL12 may be crucial in controlling PCa cell adhesion on fibronectin and collagen I, possibly via crosstalk with integrin receptors and/or altering the expression levels of integrin subunits. Mehdi Dehghani, Sedigheh Kianpour, Ana Zangeneh, and Zohreh Mostafavi-Pour Copyright © 2014 Mehdi Dehghani et al. All rights reserved. Assessment of the Potential of CDK2 Inhibitor NU6140 to Influence the Expression of Pluripotency Markers NANOG, OCT4, and SOX2 in 2102Ep and H9 Cells Mon, 17 Nov 2014 06:27:08 +0000 As cyclin-dependent kinases (CDKs) regulate cell cycle progression and RNA transcription, CDKs are attractive targets for creating cancer cell treatments. In this study we investigated the effects of the small molecular agent NU6140 (inhibits CDK2 and cyclin A interaction) on human embryonic stem (hES) cells and embryonal carcinoma-derived (hEC) cells via the expression of transcription factors responsible for pluripotency. A multiparameter flow cytometric method was used to follow changes in the expression of NANOG, OCT4, and SOX2 together in single cells. Both hES and hEC cells responded to NU6140 treatment by induced apoptosis and a decreased expression of NANOG, OCT4, and SOX2 in surviving cells. A higher sensitivity to NU6140 application in hES than hEC cells was detected. NU6140 treatment arrested hES and hEC cells in the G2 phase and inhibited entry into the M phase as evidenced by no significant increase in histone 3 phosphorylation. When embryoid bodies (EBs) formed from NU6104 treated hES cells were compared to EBs from untreated hES cells differences in ectodermal, endodermal, and mesodermal lineages were found. The results of this study highlight the importance of CDK2 activity in maintaining pluripotency of hES and hEC cells and in differentiation of hES cells. Ade Kallas, Martin Pook, Annika Trei, and Toivo Maimets Copyright © 2014 Ade Kallas et al. All rights reserved. p38δ MAPK: Emerging Roles of a Neglected Isoform Wed, 17 Sep 2014 07:52:27 +0000 p38δ mitogen activated protein kinase (MAPK) is a unique stress responsive protein kinase. While the p38 MAPK family as a whole has been implicated in a wide variety of biological processes, a specific role for p38δ MAPK in cellular signalling and its contribution to both physiological and pathological conditions are presently lacking. Recent emerging evidence, however, provides some insights into specific p38δ MAPK signalling. Importantly, these studies have helped to highlight functional similarities as well as differences between p38δ MAPK and the other members of the p38 MAPK family of kinases. In this review we discuss the current understanding of the molecular mechanisms underlying p38δ MAPK activity. We outline a role for p38δ MAPK in important cellular processes such as differentiation and apoptosis as well as pathological conditions such as neurodegenerative disorders, diabetes, and inflammatory disease. Interestingly, disparate roles for p38δ MAPK in tumour development have also recently been reported. Thus, we consider evidence which characterises p38δ MAPK as both a tumour promoter and a tumour suppressor. In summary, while our knowledge of p38δ MAPK has progressed somewhat since its identification in 1997, our understanding of this particular isoform in many cellular processes still strikingly lags behind that of its counterparts. Carol O’Callaghan, Liam J. Fanning, and Orla P. Barry Copyright © 2014 Carol O’Callaghan et al. All rights reserved. Matrix Gla Protein Binds to Fibronectin and Enhances Cell Attachment and Spreading on Fibronectin Thu, 21 Aug 2014 09:41:31 +0000 Background. Matrix Gla protein (MGP) is a vitamin K-dependent, extracellular matrix protein. MGP is a calcification inhibitor of arteries and cartilage. However MGP is synthesized in many tissues and is especially enriched in embryonic tissues and in cancer cells. The presence of MGP in those instances does not correlate well with the calcification inhibitory role. This study explores a potential mechanism for MGP to bind to matrix proteins and alter cell matrix interactions. Methods. To determine whether MGP influences cell behavior through interaction with fibronectin, we studied MGP binding to fibronectin, the effect of MGP on fibronectin mediated cell attachment and spreading and immunolocalized MGP and fibronectin. Results. First, MGP binds to fibronectin. The binding site for MGP is in a specific fibronectin fragment, called III1-C or anastellin. The binding site for fibronectin is in a MGP C-terminal peptide comprising amino acids 61–77. Second, MGP enhances cell attachment and cell spreading on fibronectin. MGP alone does not promote cell adhesion. Third, MGP is present in fibronectin-rich regions of tissue sections. Conclusions. MGP binds to fibronectin. The presence of MGP increased cell-fibronectin interactions. Satoru Ken Nishimoto and Miyako Nishimoto Copyright © 2014 Satoru Ken Nishimoto and Miyako Nishimoto. All rights reserved.