Medicine and Health Sciences Commons^™

Crosstalk Between Diacylglycerol Kinase And Protein Kinase A In The Regulation Of Airway Smooth Muscle Cell Proliferation, Miguel Angel Hernandez-Lara, Santosh Kumar Yadav, Stanley Conaway, Sushrut D. Shah, Raymond B. Penn, Phd, Deepak A. Deshpande, Phd

Center for Translational Medicine Faculty Papers

Background: Diacylglycerol kinase (DGK) regulates intracellular signaling and functions by converting diacylglycerol (DAG) into phosphatidic acid. We previously demonstrated that DGK inhibition attenuates airway smooth muscle (ASM) cell proliferation, however, the mechanisms mediating this effect are not well established. Given the capacity of protein kinase A (PKA) to effect inhibition of ASM cells growth in response to mitogens, we employed multiple molecular and pharmacological approaches to examine the putative role of PKA in the inhibition of mitogen-induced ASM cell proliferation by the small molecular DGK inhibitor I (DGK I).

Methods: We assayed cell proliferation using CyQUANT™ NF assay, protein expression …

Apoptosis Signal-Regulating Kinase 1 Inhibition Attenuates Human Airway Smooth Muscle Growth And Migration In Chronic Obstructive Pulmonary Disease., Mathew S. Eapen, Anudeep Kota, Howard Vindin, Kielan D. Mcalinden, Dia Xenaki, Brian G. Oliver, Deepak A. Deshpande, Sukhwinder Singh Sohal, Pawan Sharma

Center for Translational Medicine Faculty Papers

Increased airway smooth muscle (ASM) mass is observed in chronic obstructive pulmonary disease (COPD), which is correlated with disease severity and negatively affects lung function in these patients. Thus, there is clear unmet clinical need for finding new therapies which can target airway remodeling and disease progression in COPD. Apoptosis signal-regulating kinase 1 (ASK1) is a ubiquitously expressed mitogen-activated protein kinase (MAPK) kinase kinase (MAP3K) activated by various stress stimuli, including reactive oxygen species (ROS), tumor necrosis factor (TNF)-α, and lipopolysaccharide (LPS) and is known to regulate cell proliferation. ASM cells from COPD patients are hyperproliferative to mitogens in vitro. …

Effects Of Platelet-Activating Factor On Brain Microvascular Endothelial Cells., Eugen Brailoiu, Christine L. Barlow, Servio H. Ramirez, Mary E. Abood, G. Cristina Brailoiu

College of Pharmacy Faculty Papers

Platelet-activating factor (PAF) is a potent phospholipid mediator that exerts various pathophysiological effects by interacting with a G protein-coupled receptor. PAF has been reported to increase the permeability of the blood-brain barrier (BBB) via incompletely characterized mechanisms. We investigated the effect of PAF on rat brain microvascular endothelial cells (RBMVEC), a critical component of the BBB. PAF produced a dose-dependent increase in cytosolic Ca²⁺ concentration; the effect was prevented by the PAF receptor antagonist, WEB2086. The effect of PAF on cytosolic Ca²⁺ was abolished in Ca²⁺-free saline or in the presence of L-type voltage-gated Ca^{2+ …}

Human Gucy2c-Targeted Chimeric Antigen Receptor (Car)-Expressing T Cells Eliminate Colorectal Cancer Metastases., Michael S. Magee, Tara S. Abraham, Trevor R. Baybutt, John C. Flickinger, Natalie A. Ridge, Glen P Marszalowicz, Priyanka Prajapati, Adam R. Hersperger, Scott A. Waldman, Adam E. Snook

Department of Pharmacology and Experimental Therapeutics Faculty Papers

One major hurdle to the success of adoptive T-cell therapy is the identification of antigens that permit effective targeting of tumors in the absence of toxicities to essential organs. Previous work has demonstrated that T cells engineered to express chimeric antigen receptors (CAR-T cells) targeting the murine homolog of the colorectal cancer antigen GUCY2C treat established colorectal cancer metastases, without toxicity to the normal GUCY2C-expressing intestinal epithelium, reflecting structural compartmentalization of endogenous GUCY2C to apical membranes comprising the intestinal lumen. Here, we examined the utility of a human-specific, GUCY2C-directed single-chain variable fragment as the basis for a CAR construct targeting …

Α-Catenin-Dependent Cytoskeletal Tension Controls Yap Activity In The Heart., Alexia Vite, Caimei Zhang, Roslyn Yi, Sabrina Emms, Glenn L. Radice

Center for Translational Medicine Faculty Papers

Shortly after birth, muscle cells of the mammalian heart lose their ability to divide. At the same time, the N-cadherin/catenin cell adhesion complex accumulates at the cell termini, creating a specialized type of cell-cell contact called the intercalated disc (ICD). To investigate the relationship between ICD maturation and proliferation, αE-catenin (Ctnna1) and αT-catenin (Ctnna3) genes were deleted to generate cardiac-specific α-catenin double knockout (DKO) mice. DKO mice exhibited aberrant N-cadherin expression, mislocalized actomyosin activity and increased cardiomyocyte proliferation that was dependent on Yap activity. To assess effects on tension, cardiomyocytes were cultured on deformable polyacrylamide hydrogels of varying stiffness. When …

Cigarette Smoke Initiates Oxidative Stress-Induced Cellular Phenotypic Modulation Leading To Cerebral Aneurysm Pathogenesis., Robert M. Starke, John W. Thompson, Muhammad S. Ali, Crissey L. Pascale, Alejandra Martinez Lege, Dale Ding, Nohra Chalouhi, David M. Hasan, Pascal Jabbour, Gary K Owens, Michal Toborek, Joshua M. Hare, Aaron S. Dumont

Department of Neurosurgery Faculty Papers

OBJECTIVE: Cigarette smoke exposure (CSE) is a risk factor for cerebral aneurysm (CA) formation, but the molecular mechanisms are unclear. Although CSE is known to contribute to excess reactive oxygen species generation, the role of oxidative stress on vascular smooth muscle cell (VSMC) phenotypic modulation and pathogenesis of CAs is unknown. The goal of this study was to investigate whether CSE activates a NOX (NADPH oxidase)-dependent pathway leading to VSMC phenotypic modulation and CA formation and rupture.

APPROACH AND RESULTS: In cultured cerebral VSMCs, CSE increased expression of NOX1 and reactive oxygen species which preceded upregulation of proinflammatory/matrix remodeling genes …

Pro-Inflammatory Chemokines And Cytokines Dominate The Blister Fluid Molecular Signature In Patients With Epidermolysis Bullosa And Affect Leukocyte And Stem Cell Migration., Vitali Alexeev, Julio Cesar Salas-Alanis, Francis Palisson, Lila Mukhtarzada, Giulio Fortuna, Jouni Uitto, Andrew P. South, Olga Igoucheva

Department of Dermatology and Cutaneous Biology Faculty Papers

Hereditary epidermolysis bullosa (EB) is associated with skin blistering and the development of chronic nonhealing wounds. Although clinical studies have shown that cell-based therapies improve wound healing, the recruitment of therapeutic cells to blistering skin and to more advanced skin lesions remains a challenge. Here, we analyzed cytokines and chemokines in blister fluids of patients affected by dystrophic, junctional, and simplex EB. Our analysis revealed high levels of CXCR1, CXCR2, CCR2, and CCR4 ligands, particularly dominant in dystrophic and junctional EB. In vitro migration assays demonstrated the preferential recruitment of CCR4⁺ lymphocytes and CXCR1⁺, CXCR2⁺, …

Endothelial Cell-Derived Microparticles From Patients With Obstructive Sleep Apnea Hypoxia Syndrome And Coronary Artery Disease Increase Aortic Endothelial Cell Dysfunction., Lixin Jia, Jingyao Fan, Wei Cui, Sa Liu, Na Li, Wayne Bond Lau, Xin-Liang Ma, Jie Du, Shaoping Nie, Yongxiang Wei

Department of Emergency Medicine Faculty Papers

BACKGROUND/AIMS: Obstructive sleep apnea hypoxia syndrome (OSAHS) is an independent risk factor for coronary artery disease (CAD). Treatment of OSAHS improves clinical outcome in some CAD patients, but the relationship between OSAHS and CAD is complex. Microparticles (MPs) are shed by the plasma membrane by either physiologic or pathologic stimulation. In the current study, we investigated the role of MPs in the context of OSAHS.

METHODS AND RESULTS: 54 patients with both suspected coronary artery stenosis and OSAHS were recruited and underwent both coronary arteriography and polysomnography. Circulating MPs were isolated and analyzed by flow cytometry. CAD+OSAHS patients exhibited greater …

Decorin-Evoked Paternally Expressed Gene 3 (Peg3) Is An Upstream Regulator Of The Transcription Factor Eb (Tfeb) In Endothelial Cell Autophagy., Thomas Neill, Catherine Sharpe, Rick T. Owens, Renato V. Iozzo

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Macroautophagy is a fundamental and evolutionarily conserved catabolic process that eradicates damaged and aging macromolecules and organelles in eukaryotic cells. Decorin, an archetypical small leucine-rich proteoglycan, initiates a protracted autophagic program downstream of VEGF receptor 2 (VEGFR2) signaling that requires paternally expressed gene 3 (PEG3). We have discovered that PEG3 is an upstream transcriptional regulator of transcription factor EB (TFEB), a master transcription factor of lysosomal biogenesis, for decorin-evoked endothelial cell autophagy. We found a functional requirement of PEG3 for TFEB transcriptional induction and nuclear translocation in human umbilical vein endothelial and PAER2 cells. Mechanistically, inhibiting VEGFR2 or AMP-activated protein …

The Rna-Binding Protein Hur Contributes To Neuroinflammation By Promoting C-C Chemokine Receptor 6 (Ccr6) Expression On Th17 Cells., Jing Chen, Jennifer L. Martindale, Carole Cramer, Myriam Gorospe, Ulus Atasoy, Paul D. Drew, Shiguang Yu

Department of Neurology Faculty Papers

In both multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), the C-C chemokine receptor 6 (CCR6) is critical for pathogenic T helper 17 (Th17) cell migration to the central nervous system (CNS). Whereas many cytokines and their receptors are potently regulated via post-transcriptional mechanisms in response to various stimuli, how CCR6 expression is post-transcriptionally regulated in Th17 cells is unknown. Here, using RNA-binding protein HuR conditional knock-out (KO) and wild-type (WT) mice, we present evidence that HuR post-transcriptionally regulates CCR6 expression by binding to and stabilizing Ccr6 mRNA and by promoting CCR6 translation. We also found that HuR down-regulates several microRNA …

Calcineurin Dysregulation Underlies Spinal Cord Injury-Induced K(+) Channel Dysfunction In Drg Neurons., Benjamin M. Zemel, Tanziyah Muqeem, Eric V. Brown, Miguel Goulão, Mark W Urban, Stephen R. Tymanskyj, Angelo C. Lepore, Manuel Covarrubias

Department of Neuroscience Faculty Papers

Dysfunction of the fast-inactivating Kv3.4 potassium current in dorsal root ganglion (DRG) neurons contributes to the hyperexcitability associated with persistent pain induced by spinal cord injury (SCI). However, the underlying mechanism is not known. In light of our previous work demonstrating modulation of the Kv3.4 channel by phosphorylation, we investigated the role of the phosphatase calcineurin (CaN) using electrophysiological, molecular, and imaging approaches in adult female Sprague Dawley rats. Pharmacological inhibition of CaN in small-diameter DRG neurons slowed repolarization of the somatic action potential (AP) and attenuated the Kv3.4 current. Attenuated Kv3.4 currents also exhibited slowed inactivation. We observed similar …

Map7 Regulates Axon Collateral Branch Development In Dorsal Root Ganglion Neurons., Stephen R Tymanskyj, Benjamin Yang, Aditi Falnikar, Angelo C Lepore, Le Ma

Department of Neuroscience Faculty Papers

Collateral branches from axons are key components of functional neural circuits that allow neurons to connect with multiple synaptic targets. Like axon growth and guidance, formation of collateral branches depends on the regulation of microtubules, but how such regulation is coordinated to ensure proper circuit development is not known. Based on microarray analysis, we have identified a role for microtubule-associated protein 7 (MAP7) during collateral branch development of dorsal root ganglion (DRG) sensory neurons. We show that MAP7 is expressed at the onset of collateral branch formation. Perturbation of its expression by overexpression or shRNA knockdown alters axon branching in …

Adiponectin Partially Rescues High Glucose/High Fat-Induced Impairment Of Mitochondrial Biogenesis And Function In A Pgc-1Α Dependent Manner., H. Wang, W.-J. Yan, J.-L. Zhang, F.-Y. Zhang, C. Gao, Y.-J. Wang, W.B. Lau, L. Tao

Department of Emergency Medicine Faculty Papers

OBJECTIVE: Plasma adiponectin (APN) levels are decreased in diabetic patients. Dysfunctional mitochondrial biogenesis is involved in type 2 diabetes (T2DM) pathogenesis, by unclear mechanisms. The present study determined (1) whether myocardial mitochondrial biogenesis was impaired in cardiomyocytes exposed to a high glucose/high fat (HGHF) medium (a T2DM in vitro model), (2) the effects of APN administration upon mitochondrial biogenesis in cardiomyocytes affected by HGHF incubation, and 3) the involved underlying mechanisms.

MATERIALS AND METHODS: Neonatal rat ventricular myocytes (NRVMs) were isolated and incubated in HGHF medium. Mitochondrial function was assessed by ATP content, and fluorescent microscopic analysis of myocardial apoptosis …

Identification Of Early Gene Expression Changes In Primary Cultured Neurons Treated With Topoisomerase I Poisons., Sharyn L. Rossi, Casey J. Lumpkin, Ashlee W. Harris, Jennifer Holbrook, Cinsley Gentillon, Suzanne M. Mccahan, Wenlan Wang, Matthew E.R. Butchbach

Department of Pediatrics Faculty Papers

Topoisomerase 1 (TOP1) poisons like camptothecin (CPT) are currently used in cancer chemotherapy but these compounds can have damaging, off-target effects on neurons leading to cognitive, sensory and motor deficits. To understand the molecular basis for the enhanced sensitivity of neurons to CPT, we examined the effects of compounds that inhibit TOP1-CPT, actinomycin D (ActD) and β-lapachone (β-Lap)-on primary cultured rat motor (MN) and cortical (CN) neurons as well as fibroblasts. Neuronal cells expressed higher levels of Top1 mRNA than fibroblasts but transcript levels are reduced in all cell types after treatment with CPT. Microarray analysis was performed to identify …

Motifs Of Vdac2 Required For Mitochondrial Bak Import And Tbid-Induced Apoptosis., Shamim Naghdi, Péter Várnai, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Voltage-dependent anion channel (VDAC) proteins are major components of the outer mitochondrial membrane. VDAC has three isoforms with >70% sequence similarity and redundant roles in metabolite and ion transport. However, only Vdac2(-/-) (V2(-/-)) mice are embryonic lethal, indicating a unique and fundamental function of VDAC2 (V2). Recently, a specific V2 requirement was demonstrated for mitochondrial Bak import and truncated Bid (tBid)-induced apoptosis. To determine the relevant domain(s) of V2 involved, VDAC1 (V1) and V2 chimeric constructs were created and used to rescue V2(-/-) fibroblasts. Surprisingly, the commonly cited V2-specific N-terminal extension and cysteines were found to be dispensable for Bak …

Increased Expression Of Napdh Oxidase 4 In Systemic Sclerosis Dermal Fibroblasts: Regulation By Transforming Growth Factor Β., Sonsoles Piera-Velazquez, Alma Makul, Sergio A. Jimenez

Department of Dermatology and Cutaneous Biology Faculty Papers

OBJECTIVE: Systemic sclerosis (SSc) is characterized by severe and often progressive fibrosis of the skin and multiple internal organs. The mechanisms responsible for these alterations remain obscure, although excessive reactive oxygen species (ROS)-mediated oxidative stress has been implicated. NOX-4 is 1 of 7 isoforms of NADPH oxidase responsible for the generation of ROS. The purpose of this study was to examine NOX-4 expression in skin and cultured dermal fibroblasts from SSc patients and to examine its regulation by transforming growth factor β1 (TGFβ1).

METHODS: NOX-4 was assessed in normal and SSc skin by immunohistologic analysis and in normal and SSc …

Human Ips Cell-Derived Astrocyte Transplants Preserve Respiratory Function After Spinal Cord Injury., Ke Li, Elham Javed, Daniel Scura, Tamara J. Hala, Suneil Seetharam, Aditi Falnikar, Jean-Philippe Richard, Ashley Chorath, Nicholas J. Maragakis, Megan C. Wright, Angelo C. Lepore

Department of Neuroscience Faculty Papers

Transplantation-based replacement of lost and/or dysfunctional astrocytes is a promising therapy for spinal cord injury (SCI) that has not been extensively explored, despite the integral roles played by astrocytes in the central nervous system (CNS). Induced pluripotent stem (iPS) cells are a clinically-relevant source of pluripotent cells that both avoid ethical issues of embryonic stem cells and allow for homogeneous derivation of mature cell types in large quantities, potentially in an autologous fashion. Despite their promise, the iPS cell field is in its infancy with respect to evaluating in vivo graft integration and therapeutic efficacy in SCI models. Astrocytes express …

Mechanisms Of Activation Of Nucleus Accumbens Neurons By Cocaine Via Sigma-1 Receptor-Inositol 1,4,5-Trisphosphate-Transient Receptor Potential Canonical Channel Pathways., Jeffrey L. Barr, Elena Deliu, Gabriela Cristina Brailoiu, Pingwei Zhao, Guang Yan, Mary E. Abood, Ellen M. Unterwald, Eugen Brailoiu

College of Pharmacy Faculty Papers

Cocaine promotes addictive behavior primarily by blocking the dopamine transporter, thus increasing dopamine transmission in the nucleus accumbens (nAcc); however, additional mechanisms are continually emerging. Sigma-1 receptors (σ1Rs) are known targets for cocaine, yet the mechanisms underlying σ1R-mediated effects of cocaine are incompletely understood. The present study examined direct effects of cocaine on dissociated nAcc neurons expressing phosphatidylinositol-linked D1 receptors. Endoplasmic reticulum-located σ1Rs and inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) were targeted using intracellular microinjection. IP3 microinjection robustly elevated intracellular Ca(2+) concentration, [Ca(2+)]i. While cocaine alone was devoid of an effect, the IP3-induced response was σ1R-dependently enhanced by cocaine co-injection. Likewise, …

Mir-103a-3p Targets The 5' Utr Of Gprc5a In Pancreatic Cells., Honglei Zhou, Isidore Rigoutsos

Computational Medicine Center Faculty Papers

MicroRNAs (miRNAs) are short noncoding RNAs that regulate the expression of their targets in a sequence-dependent manner. For protein-coding transcripts, miRNAs regulate expression levels through binding sites in either the 3' untranslated region (3' UTR) or the amino acid coding sequence (CDS) of the targeted messenger RNA (mRNA). Currently, for the 5' untranslated region (5' UTR) of mRNAs, very few naturally occurring examples exist whereby the targeting miRNA down-regulates the expression of the corresponding mRNA in a seed-dependent manner. Here we describe and characterize two miR-103a-3p target sites in the 5' UTR of GPRC5A, a gene that acts as a …

Extracellular Traps Are Associated With Human And Mouse Neutrophil And Macrophage Mediated Killing Of Larval Strongyloides Stercoralis., Sandra Bonne-Annee, Laura A. Kerepesi, Jessica A. Hess, Jordan Wesolowski, Fabienne Paumet, James B. Lok, Thomas J. Nolan, David Abraham

Department of Microbiology and Immunology Faculty Papers

Neutrophils are multifaceted cells that are often the immune system's first line of defense. Human and murine cells release extracellular DNA traps (ETs) in response to several pathogens and diseases. Neutrophil extracellular trap (NET) formation is crucial to trapping and killing extracellular pathogens. Aside from neutrophils, macrophages and eosinophils also release ETs. We hypothesized that ETs serve as a mechanism of ensnaring the large and highly motile helminth parasite Strongyloides stercoralis thereby providing a static target for the immune response. We demonstrated that S. stercoralis larvae trigger the release of ETs by human neutrophils and macrophages. Analysis of NETs revealed …

Efficient B Cell Responses To Borrelia Hermsii Infection Depend On Baff And Baffr But Not Taci., Gregory S. Dickinson, Phd, Guizhi Sun, Richard J Bram, Kishore Alugupalli

Department of Microbiology and Immunology Faculty Papers

T cell-independent antibody responses develop rapidly, within 3 to 4 days, and are critical for preventing blood-borne pathogens from evolving into life-threatening infections. The interaction of BAFF, also known as BLyS, with its receptors BAFFR and TACI on B cells is critical for B cell homeostasis and function. Using a synthetic polysaccharide antigen, it has previously been shown that TACI is critical for T cell-independent antibody responses. To examine the role of BAFFR and TACI in T cell-independent antibody responses to an active infection, we utilized the Borrelia hermsii infection system. In this infection system, T cell-independent responses mediated by …

Racial Differences In Human Platelet Par4 Reactivity Reflect Expression Of Pctp And Mir-376c., Leonard Edelstein, Lukas M Simon, Raúl Teruel Montoya, Michael Holinstat, Edward S Chen, Angela Bergeron, Xianguo Kong, Srikanth Nagalla, Narla Mohandas, David E Cohen, Jing-Fei Dong, Chad Shaw, Paul Bray

Cardeza Foundation for Hematologic Research

Racial differences in the pathophysiology of atherothrombosis are poorly understood. We explored the function and transcriptome of platelets in healthy black (n = 70) and white (n = 84) subjects. Platelet aggregation and calcium mobilization induced by the PAR4 thrombin receptor were significantly greater in black subjects. Numerous differentially expressed RNAs were associated with both race and PAR4 reactivity, including PCTP (encoding phosphatidylcholine transfer protein), and platelets from black subjects expressed higher levels of PC-TP protein. PC-TP inhibition or depletion blocked PAR4- but not PAR1-mediated activation of platelets and megakaryocytic cell lines. miR-376c levels were differentially expressed by race and …

Caveolin-1 Deficiency Induces Spontaneous Endothelial-To-Mesenchymal Transition In Murine Pulmonary Endothelial Cells In Vitro., Zhaodong Li, Peter J. Wermuth, Bryan S. Benn, Michael P. Lisanti, Sergio A. Jimenez

Jefferson Institute of Molecular Medicine Papers and Presentations

It was previously demonstrated that transforming growth factor β (TGF-β) induces endothelial-to-mesenchymal transition (EndoMT) in murine lung endothelial cells (ECs) in vitro. Owing to the important role of caveolin-1 (CAV1) in TGF-β receptor internalization and TGF-β signaling, the participation of CAV1 in the induction of EndoMT in murine lung ECs was investigated. Pulmonary ECs were isolated from wild-type and Cav1 knockout mice using immunomagnetic methods with sequential anti-CD31 and anti-CD102 antibody selection followed by in vitro culture and treatment with TGF-β1. EndoMT was assessed by semiquantitative RT-PCR for Acta2, Col1a1, Snai1, and Snai2; by immunofluorescence for α-smooth muscle actin; and …

Perlecan Domain V Induces Vegf Secretion In Brain Endothelial Cells Through Integrin Α5Β1 And Erk-Dependent Signaling Pathways., Douglas N Clarke, Abraham Al Ahmad, Boyeon Lee, Christi Parham, Lisa Auckland, Andrezj Fertala, Michael Kahle, Courtney S Shaw, Jill Roberts, Gregory J Bix

Department of Dermatology and Cutaneous Biology Faculty Papers

Perlecan Domain V (DV) promotes brain angiogenesis by inducing VEGF release from brain endothelial cells (BECs) following stroke. In this study, we define the specific mechanism of DV interaction with the α(5)β(1) integrin, identify the downstream signal transduction pathway, and further investigate the functional significance of resultant VEGF release. Interestingly, we found that the LG3 portion of DV, which has been suggested to possess most of DV's angio-modulatory activity outside of the brain, binds poorly to α(5)β(1) and induces less BEC proliferation compared to full length DV. Additionally, we implicate DV's DGR sequence as an important element for the interaction …

Effect Of Oxidative Stress On Protein Tyrosine Phosphatase 1b In Scleroderma Dermal Fibroblasts., Pei-Suen Tsou, Nadine N. Talia, Adam J. Pinney, Ann Kendzicky, Sonsoles Piera-Velazquez, Sergio A. Jimenez, James R. Seibold, Kristine Phillips, Alisa E Koch

Department of Dermatology and Cutaneous Biology Faculty Papers

OBJECTIVE: Platelet-derived growth factor (PDGF) and its receptor, PDGFR, promote fibrosis in systemic sclerosis (SSc; scleroderma) dermal fibroblasts, and such cells in scleroderma skin lesions produce excessive reactive oxygen species (ROS). PDGFR is phosphorylated upon PDGF stimulation, and is dephosphorylated by protein tyrosine phosphatases (PTPs), including PTP1B. This study was undertaken to determine whether the thiol-sensitive PTP1B is affected by ROS in SSc dermal fibroblasts, thereby enhancing the phosphorylation of PDGFR and synthesis of type I collagen. This study also sought to investigate the effect of a thiol antioxidant, N-acetylcysteine (NAC), in SSc.

METHODS: Fibroblasts were isolated from the skin …

Orai1 Deficiency Leads To Heart Failure And Skeletal Myopathy In Zebrafish., Mirko Völkers, Nima Dolatabadi, Natalie Gude, Patrick Most, Mark A Sussman, David Hassel

Center for Translational Medicine Faculty Papers

Mutations in the store-operated Ca²⁺ entry pore protein ORAI1 have been reported to cause myopathies in human patients but the mechanism involved is not known. Cardiomyocytes express ORAI1 but its role in heart function is also unknown. Using reverse genetics in zebrafish, we demonstrated that inactivation of the highly conserved zebrafish orthologue of ORAI1 resulted in severe heart failure, reduced ventricular systolic function, bradycardia and skeletal muscle weakness. Electron microscopy of Orai1-deficient myocytes revealed progressive skeletal muscle instability with loss of myofiber integrity and ultrastructural abnormalities of the z-disc in both skeletal and cardiac muscle. Isolated Orai1-deficient cardiomyocytes showed loss …

The Dermatan Sulfate Proteoglycan Decorin Modulates Α2Β1 Integrin And The Vimentin Intermediate Filament System During Collagen Synthesis., Oliver Jungmann, Katerina Nikolovska, Christian Stock, Jan-Niklas Schulz, Beate Eckes, Christoph Riethmüller, Rick T Owens, Renato V Iozzo, Daniela G Seidler

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Decorin, a small leucine-rich proteoglycan harboring a dermatan sulfate chain at its N-terminus, is involved in regulating matrix organization and cell signaling. Loss of the dermatan sulfate of decorin leads to an Ehlers-Danlos syndrome characterized by delayed wound healing. Decorin-null (Dcn(-/-)) mice display a phenotype similar to that of EDS patients. The fibrillar collagen phenotype of Dcn(-/-) mice could be rescued in vitro by decorin but not with decorin lacking the glycosaminoglycan chain. We utilized a 3D cell culture model to investigate the impact of the altered extracellular matrix on Dcn(-/-) fibroblasts. Using 2D gel electrophoresis followed by mass spectrometry, …

Evidence That The Density Of Self Peptide-Mhc Ligands Regulates T-Cell Receptor Signaling., Nadia Anikeeva, Dimitry Gakamsky, Jørgen Schøller, Yuri Sykulev

Department of Microbiology and Immunology Faculty Papers

Noncognate or self peptide-MHC (pMHC) ligands productively interact with T-cell receptor (TCR) and are always in a large access over the cognate pMHC on the surface of antigen presenting cells. We assembled soluble cognate and noncognate pMHC class I (pMHC-I) ligands at designated ratios on various scaffolds into oligomers that mimic pMHC clustering and examined how multivalency and density of the pMHCs in model clusters influences the binding to live CD8 T cells and the kinetics of TCR signaling. Our data demonstrate that the density of self pMHC-I proteins promotes their interaction with CD8 co-receptor, which plays a critical role …

B1b Lymphocyte-Derived Antibodies Control Borrelia Hermsii Independent Of Fcα/Μ Receptor And In The Absence Of Host Cell Contact., Matthew J. Colombo, David Abraham, Akira Shibuya, Kishore R. Alugupalli

Department of Microbiology and Immunology Faculty Papers

The critical role of IgM in controlling pathogen burden has been demonstrated in a variety of infection models. In the murine model of Borrelia hermsii infection, IgM is necessary and sufficient for the rapid clearance of bacteremia. Convalescent, but not naïve, B1b cells generate a specific IgM response against B. hermsii, but the mechanism of IgM-mediated protection is unknown. Here, we show that neither Fcα/μR, a high-affinity receptor for IgM, nor IgM-dependent complement activation is required for controlling B. hermsii. Bacteria in diffusion chambers with a pore size impermeable to cells were killed when diffusion chambers were implanted into either …

Advanced Glycation End Products Accelerate Ischemia/Reperfusion Injury Through Receptor Of Advanced End Product/Nitrative Thioredoxin Inactivation In Cardiac Microvascular Endothelial Cells., Yi Liu, Yanzhuo Ma, Rutao Wang, Chenhai Xia, Rongqing Zhang, Kun Lian, Ronghua Luan, Lu Sun, Lu Yang, Wayne B Lau, Haichang Wang, Ling Tao

Department of Emergency Medicine Faculty Papers

The advanced glycation end products (AGEs) are associated with increased cardiac endothelial injury. However, no causative link has been established between increased AGEs and enhanced endothelial injury after ischemia/reperfusion. More importantly, the molecular mechanisms by which AGEs may increase endothelial injury remain unknown. Adult rat cardiac microvascular endothelial cells (CMECs) were isolated and incubated with AGE-modified bovine serum albumin (BSA) or BSA. After AGE-BSA or BSA preculture, CMECs were subjected to simulated ischemia (SI)/reperfusion (R). AGE-BSA increased SI/R injury as evidenced by enhanced lactate dehydrogenase release and caspase-3 activity. Moreover, AGE-BSA significantly increased SI/R-induced oxidative/nitrative stress in CMECs (as measured …