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21 results on '"André J. Ouellette"'

1. PTPN2 Is a Critical Regulator of Ileal Paneth Cell Viability and Function in MiceSummary

Author

Vinicius Canale, Marianne R. Spalinger, Rocio Alvarez, Anica Sayoc-Becerra, Golshid Sanati, Salomon Manz, Pritha Chatterjee, Alina N. Santos, Hillmin Lei, Sharon Jahng, Timothy Chu, Ali Shawki, Elaine Hanson, Lars Eckmann, André J. Ouellette, and Declan F. McCole

Subjects
Antimicrobial Peptides, TCPTP, Lysozyme, Intestinal Epithelial Cells, Inflammatory Bowel Disease, Microbiome, Diseases of the digestive system. Gastroenterology, RC799-869
Abstract

Background & Aims: Loss-of-function variants in the PTPN2 gene are associated with increased risk of inflammatory bowel disease. We recently showed that Ptpn2 is critical for intestinal epithelial cell (IEC) barrier maintenance, IEC–macrophage communication, and modulation of the gut microbiome in mice, restricting expansion of a small intestinal pathobiont associated with inflammatory bowel disease. Here, we aimed to identify how Ptpn2 loss affects ileal IEC subtypes and their function in vivo. Methods: Constitutive Ptpn2 wild-type, heterozygous, and knockout (KO) mice, as well as mice with inducible deletion of Ptpn2 in IECs, were used in the study. Investigation was performed using imaging techniques, flow cytometry, enteroid culture, and analysis of gene and protein levels of IEC markers. Results: Partial transcriptome analysis showed that expression of Paneth cell–associated antimicrobial peptides Lyz1, Pla2g2a, and Defa6 was down-regulated markedly in Ptpn2-KO mice compared with wild-type and heterozygous. In parallel, Paneth cell numbers were reduced, their endoplasmic reticulum architecture was disrupted, and the endoplasmic reticulum stress protein, C/EBP-homologous protein (CHOP), was increased in Ptpn2-KO mice. Despite reduced Paneth cell number, flow cytometry showed increased expression of the Paneth cell–stimulatory cytokines interleukin 22 and interferon γ+ in CD4+ T cells isolated from Ptpn2-KO ileum. Key findings in constitutive Ptpn2-KO mice were confirmed in epithelium-specific Ptpn2ΔIEC mice, which also showed impaired lysozyme protein levels in Paneth cells compared with Ptpn2fl/fl control mice. Conclusions: Constitutive Ptpn2 deficiency affects Paneth cell viability and compromises Paneth cell–specific antimicrobial peptide production. The observed effects may contribute to the increased susceptibility to intestinal infection and dysbiosis in these mice.

Published
2023
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2. Inhibition of miR-146a Expression and Regulation of Endotoxin Tolerance by Rhesus Theta-Defensin-1

Author

Prasad Tongaonkar, Katie K. Trinh, André J. Ouellette, and Michael E. Selsted

Subjects
Pathology, RB1-214
Abstract

Theta- (θ-) defensins are pleiotropic host defense peptides with antimicrobial- and immune-modulating activities. Immune stimulation of cells with lipopolysaccharide (LPS, endotoxin) activates proinflammatory gene expression and cytokine secretion, both of which are attenuated by rhesus theta-defensin-1 (RTD-1) inhibition of NF-κB and MAP kinase pathways. Endotoxin tolerance is a condition that ensues when cells have an extended primary exposure to low levels of LPS, resulting in resistance to a subsequent LPS challenge. Recognition of LPS by Toll-like receptor-4 (TLR4) activates NF-κB, elevating levels of microRNA-146a (miR-146a), which targets IRAK1 and TRAF6 transcripts to reduce their protein levels and inhibits TLR signaling on secondary LPS stimulation. Here, we report that RTD-1 suppressed the expression of miR-146a and stabilized the IRAK1 protein in immune-stimulated, monocytic THP-1 cells. Cells that had primary exposure to LPS became endotoxin-tolerant, as evident from their failure to secrete TNF-α upon secondary endotoxin challenge. However, cells incubated with RTD-1 during the primary LPS stimulation secreted TNF-α after secondary LPS stimulation in an RTD-1 dose-dependent manner. Consistent with this, compared to the control treatment, cells treated with RTD-1 during primary LPS stimulation had increased NF-κB activity after secondary LPS stimulation. These results show that RTD-1 suppresses endotoxin tolerance by inhibiting the NF-κB pathway and demonstrates a novel inflammatory role for RTD-1 that is mediated by the downregulation of miR-146a during the innate immune response.

Published
2023
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3. A host-directed macrocyclic peptide therapeutic for MDR gram negative bacterial infections

Author

Justin B. Schaal, Yoshihiro Eriguchi, Dat Q. Tran, Patti A. Tran, Chase Hawes, Anthony E. Cabebe, Kaitlyn Pike, Katie Trinh, André J. Ouellette, and Michael E. Selsted

Subjects
Medicine, Science
Abstract

Abstract The emergence of infections by carbapenem resistant Enterobacteriaceae (CRE) pathogens has created an urgent public health threat, as carbapenems are among the drugs of last resort for infections caused by a growing fraction of multi-drug resistant (MDR) bacteria. There is global consensus that new preventive and therapeutic strategies are urgently needed to combat the growing problem of MDR bacterial infections. Here, we report on the efficacy of a novel macrocyclic peptide, minimized theta-defensin (MTD)-12813 in CRE sepsis. MTD12813 is a theta-defensin inspired cyclic peptide that is highly effective against CRE pathogens K. pneumoniae and E. coli in vivo. In mouse septicemia models, single dose administration of MTD12813 significantly enhanced survival by promoting rapid host-mediated bacterial clearance and by modulating pathologic cytokine responses, restoring immune homeostasis, and preventing lethal septic shock. The peptide lacks direct antibacterial activity in the presence of mouse serum or in peritoneal fluid, further evidence for its indirect antibacterial mode of action. MTD12813 is highly stable in biological matrices, resistant to bacterial proteases, and nontoxic to mice at dose levels 100 times the therapeutic dose level, properties which support further development of the peptide as a first in class anti-infective therapeutic.

Published
2021
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4. Host Defense Peptides as Templates for Antifungal Drug Development

Author

Virginia Basso, Dat Q. Tran, André J. Ouellette, and Michael E. Selsted

Subjects
antifungals, host defense peptides, peptidomimetics, immunomodulation, multidrug resistance, defensins, Biology (General), QH301-705.5
Abstract

Current treatment for invasive fungal diseases is limited to three classes of antifungal drugs: azoles, polyenes, and echinocandins. The most recently introduced antifungal class, the echinocandins, was first approved nearly 30 years ago. The limited antifungal drug portfolio is rapidly losing its clinical utility due to the inexorable rise in the incidence of invasive fungal infections and the emergence of multidrug resistant (MDR) fungal pathogens. New antifungal therapeutic agents and novel approaches are desperately needed. Here, we detail attempts to exploit the antifungal and immunoregulatory properties of host defense peptides (HDPs) in the design and evaluation of new antifungal therapeutics and discuss historical limitations and recent advances in this quest.

Published
2020
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5. Killing of Staphylococci by θ-Defensins Involves Membrane Impairment and Activation of Autolytic Enzymes

Author

Miriam Wilmes, Marina Stockem, Gabriele Bierbaum, Martin Schlag, Friedrich Götz, Dat Q. Tran, Justin B. Schaal, André J. Ouellette, Michael E. Selsted, and Hans-Georg Sahl

Subjects
antimicrobial peptides, host defense peptides, defensins, antibiotics, mode of action, Therapeutics. Pharmacology, RM1-950
Abstract

θ-Defensins are cyclic antimicrobial peptides expressed in leukocytes of Old world monkeys. To get insight into their antibacterial mode of action, we studied the activity of RTDs (rhesus macaque θ-defensins) against staphylococci. We found that in contrast to other defensins, RTDs do not interfere with peptidoglycan biosynthesis, but rather induce bacterial lysis in staphylococci by interaction with the bacterial membrane and/or release of cell wall lytic enzymes. Potassium efflux experiments and membrane potential measurements revealed that the membrane impairment by RTDs strongly depends on the energization of the membrane. In addition, RTD treatment caused the release of Atl-derived cell wall lytic enzymes probably by interaction with membrane-bound lipoteichoic acid. Thus, the premature and uncontrolled activity of these enzymes contributes strongly to the overall killing by θ-defensins. Interestingly, a similar mode of action has been described for Pep5, an antimicrobial peptide of bacterial origin.

Published
2014
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6. Differential Susceptibility of Bacteria to Mouse Paneth Cell a-Defensins under Anaerobic Conditions

Author

Jennifer R. Mastroianni, Wuyuan Lu, Michael E. Selsted, and André J. Ouellette

Subjects
antimicrobial peptide, microbicide, cryptdin, facultative, microbiota, ileum, Therapeutics. Pharmacology, RM1-950
Abstract

Small intestinal Paneth cells secrete a-defensin peptides, termed cryptdins (Crps) in mice, into the intestinal lumen, where they confer immunity to oral infections and define the composition of the ileal microbiota. In these studies, facultative bacteria maintained under aerobic or anaerobic conditions displayed differential sensitivities to mouse a-defensins under in vitro assay conditions. Regardless of oxygenation, Crps 2 and 3 had robust and similar bactericidal activities against S. typhimurium and S. flexneri, but Crp4 activity against S. flexneri was attenuated in the absence of oxygen. Anaerobic bacteria varied in their susceptibility to Crps 2-4, with Crp4 showing less activity than Crps 2 and 3 against Enterococcus faecalis, and Bacteroides fragilis in anaerobic assays, but Fusobacterium necrophorum was killed only by Crp4 and not by Crps 2 and 3. The influence of anaerobiosis in modulating Crp bactericidal activities in vitro suggests that a-defensin effects on the enteric microbiota may be subject to regulation by local oxygen tension.

Published
2014
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7. A conserved β-bulge glycine residue facilitates folding and increases stability of the mouse α-defensin cryptdin-4

Author

Richard J. Clark, Thanh Huyen Phan, Angela Song, André J. Ouellette, Anne C. Conibear, and K. Johan Rosengren

Abstract

Defensins are key components of both innate and adaptive immune responses to pathogens. Cryptdins are mouse alpha-defensins that are secreted from Paneth cells in the small intestine and have disulfide-stabilised structures and antibacterial activities against both Gram-positive and Gram-negative bacteria. The folding and three-dimensional structures of alpha-defensins are thought to depend on a conserved glycine residue that forms a β-bulge. Here we investigated the role of this conserved glycine at position 19 of cryptdin-4 (Crp4) in terms of the folding, structure and stability. A Crp4 variant with D-Ala at position 19 folded efficiently, was stabilised by a large number of hydrogen bonds, and resisted proteolysis in simulated intestinal fluid. Although a variant with L-Ala at position 19 was able to adopt the correct fold, it showed less efficient folding and was degraded more rapidly than the D-Ala variant. These results demonstrate the key role that glycine residues can have in folding of bioactive peptides and can provide insights to guide design of stable antimicrobial peptides that fold efficiently.

Published
2021

8. High fidelity processing and activation of the human α-defensin HNP1 precursor by neutrophil elastase and proteinase 3.

Author

Prasad Tongaonkar, Amir E Golji, Patti Tran, André J Ouellette, and Michael E Selsted

Subjects
Medicine, Science
Abstract

The azurophilic granules of human neutrophils contain four α-defensins called human neutrophil peptides (HNPs 1-4). HNPs are tridisulfide-linked antimicrobial peptides involved in the intracellular killing of organisms phagocytosed by neutrophils. The peptides are produced as inactive precursors (proHNPs) which are processed to active microbicides by as yet unidentified convertases. ProHNP1 was expressed in E. coli and the affinity-purified propeptide isolated as two species, one containing mature HNP1 sequence with native disulfide linkages ("folded proHNP1") and the other containing non-native disulfide linked proHNP1 conformers (misfolded proHNP1). Native HNP1, liberated by CNBr treatment of folded proHNP1, was microbicidal against Staphylococcus aureus, but the peptide derived from misfolded proHNP1 was inactive. We hypothesized that neutrophil elastase (NE), proteinase 3 (PR3) or cathepsin G (CG), serine proteases that co-localize with HNPs in azurophil granules, are proHNP1 activating convertases. Folded proHNP1 was converted to mature HNP1 by both NE and PR3, but CG generated an HNP1 variant with an N-terminal dipeptide extension. NE and PR3 cleaved folded proHNP1 to produce a peptide indistinguishable from native HNP1 purified from neutrophils, and the microbicidal activities of in vitro derived and natural HNP1 peptides were equivalent. In contrast, misfolded proHNP1 conformers were degraded extensively under the same conditions. Thus, NE and PR3 possess proHNP1 convertase activity that requires the presence of the native HNP1 disulfide motif for high fidelity activation of the precursor in vitro.

Published
2012
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9. Decreased Paneth cell α-defensins promote fibrosis in a choline-deficient L-amino acid-defined high-fat diet-induced mouse model of nonalcoholic steatohepatitis via disrupting intestinal microbiota

Author

Shunta Nakamura, Kiminori Nakamura, Yuki Yokoi, Yu Shimizu, Shuya Ohira, Mizu Hagiwara, Zihao Song, Li Gan, Tomoyasu Aizawa, Daigo Hashimoto, Takanori Teshima, Andre J. Ouellette, and Tokiyoshi Ayabe

Subjects
Medicine, Science
Abstract

Abstract Nonalcoholic steatohepatitis (NASH) is a chronic liver disease characterized by fibrosis that develops from fatty liver. Disruption of intestinal microbiota homeostasis, dysbiosis, is associated with fibrosis development in NASH. An antimicrobial peptide α-defensin secreted by Paneth cells in the small intestine is known to regulate composition of the intestinal microbiota. However, involvement of α-defensin in NASH remains unknown. Here, we show that in diet-induced NASH model mice, decrease of fecal α-defensin along with dysbiosis occurs before NASH onset. When α-defensin levels in the intestinal lumen are restored by intravenous administration of R-Spondin1 to induce Paneth cell regeneration or by oral administration of α-defensins, liver fibrosis is ameliorated with dissolving dysbiosis. Furthermore, R-Spondin1 and α-defensin improved liver pathologies together with different features in the intestinal microbiota. These results indicate that decreased α-defensin secretion induces liver fibrosis through dysbiosis, further suggesting Paneth cell α-defensin as a potential therapeutic target for NASH.

Published
2023
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10. Paneth Cells in Intestinal Health and Disease in the Newborn

Author

André J. Ouellette and Victoria Niklas

Subjects
Innate immune system, Lipopolysaccharide, Inflammation, Biology, digestive system, Bacterial cell structure, Proinflammatory cytokine, Microbiology, chemistry.chemical_compound, medicine.anatomical_structure, chemistry, Pediatrics, Perinatology and Child Health, Paneth cell, Immunology, medicine, Secretion, Lipoteichoic acid, medicine.symptom
Abstract

Immunologic defense mechanisms of the adaptive and innate immune systems coordinate a balance between host defense and overreaction to the proinflammatory stimuli of the resident microflora in the intestinal tract. Among cells of the intestinal innate immune system, Paneth cells, located in the small intestinal crypts of Lieberkühn, have evolved to provide immediate responses to bacteria as well as shape the composition of commensal bacterial flora in the small intestine. Paneth cells release secretory granules rich in a variety of proteins involved in host defense and inflammation, including alpha-defensins. Alpha-defensins are small, cationic peptides that exhibit a broad spectrum of antimicrobial actions. In addition, Paneth cell granules contain other antibacterial substances, including lysozyme, secretory phospholipase A2, lectins, and a variety of immunomodulatory cytokines. Paneth cell secretion is stimulated by bacteria or by components of bacterial cell envelopes, such as lipopolysaccharide and lipoteichoic acid. The number of Paneth cells, their expression of alpha-defensins, and their expression of proteins involved in the detection of luminal bacteria are reduced in fetuses compared with term newborns and adults. Hence, reduced Paneth cell numbers and immaturity in the production of antibacterial products or their ability to detect bacteria may predispose newborns, and preterm infants in particular, to pathogenic bacterial overgrowth and translocation, contributing to the development of bacteremia, sepsis, and intestinal inflammation in diseases such as necrotizing enterocolitis.

Published
2010

11. Contributors

Author

Valérie Abadie, Clara Abraham, David H. Adams, William W. Agace, Jennifer Alexander-Brett, Omar Alkhairy, Ines Ambite, Deborah J. Anderson, David Artis, Robert L. Atmar, Laetitia Aymeric, Claus Bachert, Jantine E. Bakema, Kristi Baker, Kenneth W. Beagley, A.D. Befus, Mats Bemark, M. Cecilia Berin, Margot Berings, Jay A. Berzofsky, Martin Bilej, Nabanita Biswas, Richard S. Blumberg, John Bienenstock, Dimitrios Bogdanos, Monica Boirivant, Kobporn Boonnak, Ken R. Bracke, Per Brandtzaeg, Jonathan Braun, Marie-Agnès Bringer, Andrew J. Broadbent, Richard Bronson, Guy G. Brusselle, Judith N. Bulmer, J.E. Butler, Paul A. Cardenas, John J. Cebra, Marina Cella, Andrea Cerutti, Stephen J. Challacombe, Kuldeep Chattha, Hilde Cheroutre, Tsutomu Chiba, Alejo Chorny, John D. Clements, Marco Colonna, William O.C. Cookson, Lynette B. Corbeil, Blaise Corthésy, Allan W. Cripps, Koen van Crombruggen, Andre Pires da Cunha, Susanna Cunningham-Rundles, Roy Curtiss, Arlette Darfeuille-Michaud, Wouter J. de Jonge, Livija Deban, Timothy L. Denning, James P. Di Santo, Andreas Diefenbach, Victor J. DiRita, Jordan Downey, Ming-Qing Du, Karen L. Edelblum, Marjolein van Egmond, H.-J. Epple, Sidonia Fagarasan, John V. Fahey, Michael J. Ferris, Stefan Fichtner-Feigl, Paul L. Fidel, Melanie Flach, Richard Flavell, Howard B. Fleit, Genoveffa Franchini, Lucy C. Freytag, Anja Fuchs, kohtaro Fujihashi, Ivan J. Fuss, Nicola Gagliani, Marta Rodriguez Garcia, Wendy S. Garrett, M. Eric Gershwin, Philippe Gevaert, Maree Gleeson, Gabriela Godaly, Randall M. Goldblum, Naina Gour, Mayda Gursel, George Hajishengallis, Hamida Hammad, Lennart Hammarström, Arno Hänninen, Lars Å. Hanson, Adrian Hayday, Ronit Herzog, Douglas C. Hodgins, Stephen T. Holgate, Jan Holmgren, Michael J. Holtzman, Edward W. Hook, Samuel Huber, Julia L. Hurwitz, Juraj Ivanyi, Akiko Iwasaki, Bana Jabri, Susan Jackson, Jonathan Jacobs, Sirpa Jalkanen, Edward N. Janoff, Ann E. Jerse, Mangalakumari Jeyanathan, Bruce A. Julian, Imre Kacskovics, Charlotte S. Kaetzel, Charu Kaushic, Brian L. Kelsall, Sarah Kessans, Rebecca Kesselring, Mogens Kilian, Hiroshi Kiyono, Dennis M. Klinman, Marina Korotkova, Mitchell Kronenberg, Olga Krysko, Yuichi Kurono, Miloslav Kverka, Bart N. Lambrecht, Michael E. Lamm, Olivier Lantz, Gendie E. Lash, E.C. Lavelle, Leo Lefrancois, Patrick S.C. Leung, Myron M. Levine, David J. Lim, John Lippolis, Nancy A. Louis, Andrew D. Luster, Nataliya Lutay, Nils Lycke, Andrew J. Macpherson, Nicholas J. Mantis, Harold Marcotte, David H. Martin, Hugh S. Mason, Helen M. Massa, Nobuyuki Matoba, Lloyd Mayer, Craig L. Maynard, M. Juliana McElrath, C. McEntee, Jerry R. McGhee, Michael A. McGuckin, Jiri Mestecky, Zamaneh Mikhak, Robert D. Miller, Zina Moldoveanu, Paul C. Montgomery, Tsafrir Mor, Markus F. Neurath, Katrijn Neyt, Lindsay K. Nicholson, Jan Novak, Stella Nowicki, D.T. O’Hagan, Nancy L. O’Sullivan, Pearay Ogra, Carlos Orihuela, André J. Ouellette, Robert L. Owen, Oliver Pabst, Charles A. Parkos, Viviana Parreño, Mickey V. Patel, Claudina Perez-Novo, Darren J. Perkins, Calman Prussin, Jeffrey Pudney, Sukanya Raghavan, Pascal Rainard, Sasirekha Ramani, Troy D. Randall, Milan Raska, Gourapura J. Renukaradhya, Maria Rescigno, Kenneth L. Rosenthal, Marc E. Rothenberg, Frank M. Ruemmele, Michael W. Russell, Linda J. Saif, Irene Salinas, Marko Salmi, Henri Salmon, Hugh A. Sampson, Philippe Sansonetti, T. Schneider, Nicolas Serafini, Dolly Sharma, Zheng Shen, Hai Ning Shi, Penelope J. Shirlaw, Sourima B. Shivhare, Phillip D. Smith, Patrick M. Smith, Daniel J. Smith, Lesley E. Smythies, Jo Spencer, Warren Strober, Kanta Subbarao, Catharina Svanborg, Ann-Mari Svennerholm, Martin A. Taubman, Esbjörn Telemo, Martin H. Thornhill, David J. Thornton, Eva Thuenemann, Helena Tlaskalova-Hogenova, Debra Tristram, Palak Trivedi, Elaine Tuomanen, Jaroslav Turanek, Jerrold R. Turner, Brian J. Underdown, Mary J. van Helden, Ronald S. Veazey, Elena F. Verdu, Anastasia Vlasova, Harissios Vliagoftis, Stefanie N. Vogel, W. Allan Walker, Xiaolei Wang, Tomohiro Watanabe, Casey T. Weaver, Howard L. Weiner, Jerry M. Wells, Ting Wen, Judith Whittum-Hudson, Jeffrey A. Whitsett, Ifor R. Williams, Marsha Wills-Karp, Charles R. Wira, Jenny M. Woof, Andrew C. Wotherspoon, Zhou Xing, Huanbin Xu, Colby Zaph, Sebastian Zeissig, and M. Zeitz

Published
2015

12. Contributors

Author

Reidunn B. Aalen, Yasser H.A. Abdel-Wahab, Michael E. Adams, Roger A.H. Adan, Rexford S. Ahima, Naima Ahmed, Omar Al-Massadi, Miriam Altstein, Youssef Anouar, Laura Anselmi, Siegfried Ansorge, Nikolinka Antcheva, Yevgeniya Antonova-Koch, Jon R. Appel, Anam J. Arik, Alison L. Arter, Peter Arvan, Avraham Ashkenazi, P.W. Baas, André Bado, Andrew Baird, Monica Baiula, Lauren O. Bakaletz, Earl E. Bakken, Márta Balaskó, Graham S. Baldwin, William A. Banks, Donatella Barra, Jessica R. Barson, Magali Basille, Natalie N. Bauer, Andrea Bedini, Christine Beeton, David J. Begley, Margery C. Beinfeld, William G. Bendena, Stephen C. Benoit, Itay Bentov, Howard Bern, Gabriele Bierbaum, Charles J. Billington, Anna Blasiak, Norman L. Block, Stephen. R. Bloom, Iwona Bonney, John H. Bowie, Sunny K. Boyd, Susan D. Brain, Dag A. Brede, Jozef Vanden Broeck, Kelly L. Brown, Mark R. Brown, James M. Bugni, Jens R. Bundgaard, Delphine Burel, Melinka A. Butenko, Melissa J. Call, Girolamo Calò, Duncan John Campbell, Anna Carlsson, Daniel B. Carr, Robert E. Carraway, Marcos C. Carreira, Felipe F. Casanueva, Sarah N. Cassella, Stuart A. Casson, Justo P. Castaño, Marek Cebrat, Valerie Chappe, David Chatenet, Keqiang Chen, Chen Chen, Longchuan Chen, Duan Chen, Carrie Y.Y. Cheng, Sung Ki Cho, Billy K.C. Chow, Arthur Christopoulos, Shijian Chu, Iain J. Clarke, Geoffrey M. Coast, Vincent Compere, Gisela P. Concepcion, Roger D. Cone, J. Michael Conlon, Germaine Cornélissen, Maité Courel, Réjean Couture, W.A. Cramer, Nathan P. Croft, Ana B. Crujeiras, Frank Cuttitta, Holger Cynis, F. D’Acquisto, Jon F. Davis, Thomas P. Davis, Claire Barbier de La Serre, Guillaume de Lartigue, Luis de Lecea, Marcelo de Oliveira Santos, Michel De Waard, Carolyn F. Deacon Bolette Hartmann, Charlène Delestre, Mario Delgado, Hans-Ulrich Demuth, Xiaoming Deng, Palitha Dharmawardhana, Anna Di Cosmo, Simoni Campos Dias, Jonathan W. Dickerson, Dzung B. Diep, H. Dircksen, Jasmin Dischinger, Jean-Claude do Rego, Paul R. Dobner, Graham J. Dockray, Robert M. Dores, Robert Ducroc, Nadine L. Dudek, Yvan Dumont, Celine Duraffourd, Dominique Duterte-Boucher, Alex N. Eberlé, Richard D. Egleton, Betty A. Eipper, Jorg B. Engel, Ella W. Englander, Jacques Epelbaum, Charlotte Erlanson-Albertsson, S. Evangelista, Karen A. Fagan, Joshua M. Farber, Klára Farkasfalvi, Csaba Fekete, Peter R. Flatt, R.J. Flower, Wolf-Georg Forssmann, Alain Fournier, Kevin Chu Foy, Octávio Luiz Franco, Dan Frenkel, Lloyd D. Fricker, César de la Fuente-Núñez, Hiroo Fukuda, Gerd Gäde, Ludovic Galas, Patricia E. Gallagher, Pierrick Gandolfo, Maria A. Garcia-Espinosa, Josune García-Sanmartín, Nori Geary, Hua Geng, Patrizia M. Germano, Jens P. Goetze, Alexis A. Gonzalez, Ana Gonzalez, Blake A. Gosnell, Katsutoshi Goto, Guillaume Gourcerol, I. Gozes, Francisco Gracia-Navarro, Bernadette E. Grayson, George H. Greeley, Megan Greenwald-Yarnell, Pierre Gressens, John R. Grider, Jan Grünewald, Juliano R. Guerreiro, Remo Guerrini, Filomena Guida, Laure Guilhaudis, Sandra Guilmeau, Andrew L. Gundlach, Jolanta Gutkowska, Clifton Hackbarth, Y. Haim Ohana, Franz Halberg, Mathias Hallberg, Sayyed A. Hamidi, Song Han, Ji-Sheng Han, Robert E.W. Hancock, Samer-ul Haque, Ikuko Hara-Nishimura, Aliza Hariton, Wendy J. Hartsock, Alan L. Harvey, Itaru Hasunuma, Robert J. Henning, Kristy M. Heppner, Kate L. Hertweck, Herbert Herzog, Tetsuya Higashiyama, Shuji Hinuma, Stefan Hippenstiel, Yuki Hirakawa, Shuichi Hirose, Jochen R. Hirsch, Andreas C. Hocke, Robert S. Hodges, Werner Hoffmann, Tomas Hökfelt, Jens Juul Holst, Peter Holzer, Frank M. Horodyski, Hiroshi Hosoda, Xiaowen Hou, Alisa Huffaker, Norio Iijima, Momoko Ikeuchi, Julita S. Imperial, Giovanna Improta, Akio Inui, Nigel Irwin, Munehiro Ishii, Xavier Iturrioz, Ljubica Ivanisevic, Hiroshi Iwao, Takeo Iwata, Yasukatsu Izumi, Hajime Izumiyama, Marek Jankowski, Tom Janssen, Sylvie Jégou, Robert T. Jensen, Preeti H. Jethwa, Helene Johannessen, Conrad Johanson, Valeria Judkowski, Przemyslaw Kaczmarek, Haruaki Kageyama, Tatsuo Kakimoto, Ki Sung Kang, Kenji Kangawa, Abba J. Kastin, Johji Kato, Pravin T.P. Kaumaya, Richard F. Keep, William R. Kem, Tetyana Khomenko, Sakae Kikuyama, Young-Joon Kim, Sadao Kimura, Ross King, Paul Kiptoo, Ichiro Kishimoto, Kazuo Kitamura, Alicja Kluczyk, Hiroyuki Kobori, Yosuke Kodama, Masayasu Kojima, Yuki Kondo, Meike Körner, Piotr Kosson, Catherine M. Kotz, Bhavani Krishnan, Bård Kulseng, Robert Kumpf, Marc Laburthe, Hélène Lacaille, Ellen E. Ladenheim, Ali Ladram, Marlyn D. Laksitorini, David G. Lambert, Angela B. Lange, Wolfgang Langhans, Muriel Larauche, Dan Larhammar, Ignacio M. Larráyoz, Roberta Lattanzi, Ronald M. Lechan, Benjamin Lefranc, Sarah F. Leibowitz, Vincent Lelièvre, Jérôme Leprince, Allen S. Levine, Qun Li, Veronica Lifshitz, Isabelle Lihrmann, James Chi-Jen Lin, Iris Lindberg, Keith Lindsey, Andrzej W. Lipkowski, T. Liron, Junli Liu, Ying Liu, Min Liu, Catherine Llorens-Cortes, Marilena Loizidou, C. Lopez, David A. Lovejoy, Vincenzo Luca, Thomas A. Lutz, Sherie Ma, Richard E. Mains, Maria M. Malagon, Ludwik K. Malendowicz, Jennifer Man-Fan Wan, Maria Luisa Mangoni, Michaele B Manigrasso, Mohamed A. Marahiel, Heather G. Marco, Christine Maric-Bilkan, Nikki J. Marks, Roland Martin, Vicente Martinez, Alfredo Martínez, Antonio J. Martinez-Fuentes, Edward P. Masler, Yoshikatsu Matsubayashi, Harman S. Mattu, Aaron G. Maule, Patricia J. McLaughlin, Ivan F. McMurtry, Ellen Meelkop, Saher Mehdi, Pietro Melchiorri, R.P. Millar, Laurence J. Miller, Miles Miller, Mulugeta Million, Naoto Minamino, M. Mittelman, Takashi Miyauchi, Mikiya Miyazato, Hirokazu Mizoguchi, Malte Mohme, Maité Montero-Hadjadje, Terry W. Moody, Neeloffer Mookherjee, Timothy H. Moran, Irene Morganstern, Masatomo Mori, Fabrice Morin, John F. Morris, Daniel S. Moura, Anna J. Mudge, Joram D. Mul, Karnam S. Murthy, Martin G. Myers, Ronald J. Nachman, Jean-Louis Nahon, Sushma Naithani, Tomoaki Nakada, Tomoya Nakamachi, Yuki Nakamura, Natalia N. Nalivaeva, June B. Nasrallah, Dick R. Nässel, L. Gabriel Navar, Pratap Neelakantan, Lucia Negri, Ingolf F. Nes, D. Neumann, Cindy Neveu, Tzi Bun Ng, Stephanie Y.L. Ng, Graham M. Nicholson, Pierre Nicolas, Toshio Nishikimi, Mariko Nishiyama, Rubén Nogueiras, Raymond S. Norton, Laura A. Novotny, Krzysztof W. Nowak, Fred Nyberg, Laura Ochoa-Callejero, Sven Ove Ögren, Hideko Ohgusu, Shinsuke Oh-I, Opeolu O. Ojo, Baldomero M. Olivera, Francisco E. Olucha-Bordonau, Joost J. Oppenheim, Ian Orchard, André J. Ouellette, Gustavo Pacheco-López, Nigel M. Page, Mario Sergio Palma, Weihong Pan, Yoonseong Park, Marc Parmentier, Sandrine Passemard, Michael Patterson, Brankica Paunovic, Gregory Pearce, Jens Pedersen, Theo L. Peeters, A. Eugene Pekary, Georges Pelletier, Simona Perboni, Diego Pérez-Tilve, Ábel Perjés, M. Perretti, Erika Pétervári, Clemencia Pinilla, Jacek Pinskim, Joseph R. Pisegna, Kristof Plankensteiner, Sonia Podvin, Pierre Poitras, Gianluca Polese, David M. Pollock, William Farias Porto, Lourival D. Possani, Charalabos Pothoulakis, Françoise Presse, Minolfa C. Prieto, S. Prutchi-Sagiv, Anthony W. Purcell, Louise Purtell, Rémi Quirion, Catalina Abad Rabat, Miriam Rademaker, Gautam Rajpal, Harpal S. Randeva, Sylvie Rebuffat, Joseph R. Reeve, Jens F. Rehfeld, Dirk Reinhold, Rainer K. Reinscheid, Jean Claude Reubi, Katayoun Rezvani, Suzana Meira Ribeiro, D. Richard, Mark Richards, Michael A. Riehle, Andrea C. Rinaldi, Bernd M. Rode, Ricardo C. Rodríguez de la Vega, Susan Rotzinger, Marcin Rucinski, Heikki Ruskoaho, Philip J. Ryan, Jean-Marc Sabatier, Hans-Georg Sahl, Sami I. Said, Tsukasa Sakurada, Shinobu Sakurada, David S. Salomon, Willis K. Samson, Zsuzsanna Sandor, H. Uri Saragovi, Kazuki Sasaki, Takahiro Sato, Ryousuke Satou, Shinichiro Sawa, Ayman I. Sayegh, Andrew V. Schally, Stephan Schilling, Liliane Schoofs, David A. Schooley, Mitchell L. Schubert, Isabelle Segalas-Milazzo, Nabil G. Seidah, Michael E. Selsted, Kim B. Seroogy, Cinzia Severini, Patrick M. Sexton, Yechiel Shai, O. Sharma, Masayoshi Shichiri, Tomoo Shimada, Hiroyuki Shimizu, Seiji Shioda, Arthur Shulkes, Teruna J. Siahaan, Ignacy Z. Siemion, Osmar Nascimento Silva, Marcio C. Silva-Filho, Mariusz Skwarczynski, Caroline. J. Small, Craig M. Smith, David E. Smith, A. Ian Smith, Beka Solomon, Travis E. Solomon, Mireia Sospedra, M.C. Souroujon, Santi Spampinato, Eliot R. Spindel, A. Steiger, Andreas Stengel, Catia Sternini, Frederik J. Steyn, Edward Stopa, Mathias Z. Strowski, Shigeo S. Sugano, Görel Sundström, J. Gregor Sutcliffe, Norbert Suttorp, Jonathan V. Sweedler, Sandor Szabo, Miklós Székely, István Szokodi, Yvette Taché, Kazuhiro Takahashi, Yoshio Takei, Fumiko Takenoya, Sébastien Talbot, E. Ann Tallant, Tricia M. Tan, Liesbet Temmerman, Bettina Temmesfeld-Wollbrück, Manuel Tena-Sempere, Annika Thorsell, Nanda Tilakaratne, Stephen S. Tobe, Takeshi Tokudome, Ganna Tolstanova, Marie-Christine Tonon, Jennifer F. Topping, Alessandro Tossi, Hervé Tostivint, Istvan Toth, Kazuhito Totsune, Fumiyo Toyoda, Rachel Troke, Matthias H. Tschöp, Patrick Tso, Hirokazu Tsukaya, Kazuyoshi Tsutsui, Hong Tu, Anthony J. Turner, Takayoshi Ubuka, Elene R. Valdivia, Hans Peter Vandersmissen, David Vaudry, Hubert Vaudry, Rafael Vazquez-Martinez, Joseph G. Verbalis, Daniele Vicari, Nicolas Vidal, Marzia Vignoni, Cécile Viollet, K.S. Vishwanatha, Mirella Vivoli, Thierry Voisin, John P. Vu, John C. Walker, B.A. Wallace, Ji Ming Wang, Lixin Wang, Jonathan H. Wardman, Takuya Watanabe, Hazel Welch, Haim Werner, L. Whitmore, Imke Wiedemann, Raphaelle Winsky-Sommerer, Ken A. Witt, Tatiana Wojciechowicz, Jack Ho Wong, Stephen C. Woods, Denise Wootten, Vincent Wu, Olivier Wurtz, Ximing Xiong, Zhi-Qing David Xu, Yube Yamaguchi, Takahiro Yamaguchi, Kazutoshi Yamamoto, E. Yamashita, Hiroyuki Yamazaki, De Yang, Masaaki Yoshikawa, Pu-Qing Yuan, Sunny C. Yung, Ian S. Zagon, S.D. Zakharov, Mehfuz Zaman, M.V. Zhalnina, Ning Zhang, Lixin Zhang-Auberson, Chun-Mei Zhao, Agnieszka Ziolkowska, and Dusan Zitnan

Published
2013

13. Contributors

Author

Clara Abraham, Maria T. Abreu, Yasutada Akiba, James M. Anderson, Qasim Aziz, Kristi Baker, Graham S. Baldwin, John A. Barnard, Adil E. Bharucha, Khalil N. Bitar, L. Ashley Blackshaw, Richard S. Blumberg, Guido T. Bommer, Joel C. Bornstein, Stuart M. Brierley, Simon J.H. Brookes, Celia Chao, Judy Cho, Steven J. Coen, James F. Collins, Peter J. Dempsey, Sang Don Koh, Ella W. Englander, Hideki Enomoto, Eric R. Fearon, Edda Fiebiger, Mark R. Frey, Masayuki Fukata, Shin Fukudo, John B. Furness, Fayez K. Ghishan, Merritt G. Gillilland, Robert R. Gilmont, Guillermo A. Gomez, George H. Greeley, Rachel M. Gwynne, Maggie Ham, Andrea Harrington, Geoffrey S. Hebbard, Mark R. Hellmich, Gerlinda E. Hermann, Scott Herness, Anthony R. Hobson, Peter Holzer, Michael Horowitz, Gary B. Huffnagle, Patrick Hughes, Sudarshan R. Jadcherla, Finn-Eirik Johansen, Leonard R. Johnson, Jonathan P. Katz, Jonathan D. Kaunitz, John F. Kuemmerle, Jennifer S. Labus, Brigitte Lavoie, Wayne I. Lencer, David R. Linden, Thomas Y. Ma, Ramiro Massol, Gary M. Mawe, Emeran A. Mayer, Kirk M. McHugh, Juanita L. Merchant, Ravinder K. Mittal, Marshall H. Montrose, Bruce D. Naliboff, Mark T. Nelson, Donald F. Newgreen, D. Brent Polk, Daniel P. Poole, Maria J. Pozo, Shreya Raghavan, Ramesh M. Ray, Christopher K. Rayner, Richard C. Rogers, Enrique Rozengurt, Linda C. Samuelson, Kenton M. Sanders, Reza Shaker, Henrik Sjövall, Sita Somara, Joseph H. Szurszewski, Jan Tack, Koji Takeuchi, Marie-Pier Tetreault, Kirsten Tillisch, Jerrold R. Turner, Gijs R. van den Brink, Willemijn A. van Dop, Kelli L. VanDussen, Arnold Wald, Sean M. Ward, Jackie D. Wood, Nicholas A. Wright, Hua Xu, Vincent W. Yang, Heather M. Young, Vincent B. Young, Nada A. Abumrad, Waddah A. Alrefai, Kiran S. Ambatipudi, Rana F. Ammoury, Gregory J. Anderson, Barry E. Argent, Alip Borthakur, R.Maynard Case, Marcelo A. Catalán, Zhouji Chen, Xiaodong Cheng, Oleg G. Chepurny, Robert J. Cousins, John Cuppoletti, Nicholas O. Davidson, Paul A. Dawson, Guillaume de Lartigue, Pradeep K. Dudeja, John G. Forte, Vadivel Ganapathy, Ravinder K. Gill, Fred S. Gorelick, D.Neil Granger, Michael A. Gray, Matthew B. Grisham, Earl H. Harrison, Gail Hecht, Bruce A. Hirayama, Kim Hodges, George G. Holt, Dawn A. Israel, James D. Jamieson, Serhan Karvar, Christopher G. Kevil, Pawel R. Kiela, Kris V. Kowdley, Nicholas F. LaRusso, Colin A. Leech, Rodger A. Liddle, Sumei Liu, Donald D.F. Loo, John P. Lynch, Wallace K. MacNaughton, Danuta H. Malinowska, Charles M. Mansbach, Anatoliy I. Masyuk, Tatyana V. Masyuk, Derek M. McKay, James E. Melvin, Donald J. Messner, Mark B. Meyer, Karen F. Murray, Ebba Nexo, Curtis Okamoto, Bernardo Ortega, André J. Ouellette, Richard M. Peek, J. Wesley Pike, Helen E. Raybould, Anil K. Rustgi, Hamid M. Said, Monica Sala-Rabanal, Mitchell L. Schubert, Ursula Seidler, Markus Sjöblom, Johan D. Söderholm, Martin C. Steward, Jay R. Thiagarajah, A.S. Verkman, Paul A. Welling, John A. Williams, Allan W. Wolkoff, Ernest M. Wright, Xuebiao Yao, and David I. Yule

Published
2012

14. Paneth Cells

Author

André J. Ouellette

Subjects
Biology
Published
2012

15. Small-angle X-ray scattering studies of peptide-lipid interactions using the mouse paneth cell α-defensin cryptdin-4

Author

Abhijit, Mishra, Kenneth P, Tai, Nathan W, Schmidt, André J, Ouellette, and Gerard C L, Wong

Subjects
Models, Molecular, Mice, Paneth Cells, alpha-Defensins, X-Ray Diffraction, Scattering, Small Angle, Animals, Peptides, Lipids
Abstract

In the presence of specialized proteins or peptides, a biological membrane can spontaneously restructure itself to allow communication between the intracellular and the extracellular sides. Examples of these proteins include cell-penetrating peptides and antimicrobial peptides (AMPs), which interact with cell membranes in complex ways. We briefly review cell-penetrating peptides and AMPs, and describe in detail how recombinant AMPs are made and their activity evaluated, using α-defensins as a specific example. We also review X-ray scattering methods used in studying peptide-membrane interactions, focusing on the procedures for small-angle X-ray scattering experiments on peptide-membrane interactions at realistic solution conditions, using both laboratory and synchrotron sources.

Published
2011

16. Expression and purification of recombinant alpha-defensins and alpha-defensin precursors in Escherichia coli

Author

Sharel, Figueredo, Jennifer R, Mastroianni, Kenneth P, Tai, and André J, Ouellette

Subjects
Chromatography, Reverse-Phase, alpha-Defensins, Recombinant Fusion Proteins, Genetic Vectors, Molecular Sequence Data, Gene Expression, Recombinant Proteins, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Escherichia coli, Electrophoresis, Polyacrylamide Gel, Amino Acid Sequence, Cloning, Molecular, Chromatography, High Pressure Liquid, Plasmids
Abstract

Recombinant expression of alpha-defensins can be obtained at efficient levels in Escherichia coli. Amplified alpha-defensin or pro-alpha-defensin coding cDNA sequences are cloned directionally between EcoRI and SalI sites of the pET-28a expression vector and expressed in E. coli BL21 RIS cells. Cells growing exponentially in nutrient-rich liquid medium are induced to express the recombinant protein by addition of 50 mM isopropyl beta-D-1-thiogalactopyranoside for 3-6 h. After bacterial cells collected by centrifugation are lysed in 6 M guanidine-HCl under non-reducing conditions, the expressed defensin fused to its 6xHis-34 amino acid N-terminal fusion partner is purified by affinity chromatography on nickel-NTA columns. A Met codon introduced at the N terminus of expressed Met-free peptides provides a unique CNBr cleavage site, enabling release of the alpha-defensin free of ancillary residues by sequential C18 RP-HPLC. Molecular masses of C18 RP-HPLC purified peptides are confirmed by MALDI-TOF mass spectrometry, and peptide homogeneity is assessed using analytical RP-HPLC and acid-urea polyacrylamide gel electrophoresis. alpha-Defensins prepared in this manner are biochemically equivalent to the natural molecules.

Published
2010

17. Elevated expression of Paneth cell CRS4C in ileitis-prone SAMP1/YitFc mice: regional distribution, subcellular localization, and mechanism of action

Author

Michael T, Shanahan, Alda, Vidrich, Yoshinori, Shirafuji, Claire L, Dubois, Agnes, Henschen-Edman, Susan J, Hagen, Steven M, Cohn, and André J, Ouellette

Subjects
Paneth Cells, alpha-Defensins, Secretory Vesicles, Immunology, Mice, Inbred Strains, Ileitis, digestive system, Recombinant Proteins, Anti-Bacterial Agents, Defensins, Mice, Inbred C57BL, Mice, Ileum, Matrix Metalloproteinase 7, Animals, Tissue Distribution, RNA, Messenger, Protein Precursors
Abstract

Paneth cells at the base of small intestinal crypts of Lieberkühn secrete host defense peptides and proteins, including alpha-defensins, as mediators of innate immunity. Mouse Paneth cells also express alpha-defensin-related Defcr-rs genes that code for cysteine-rich sequence 4C (CRS4C) peptides that have a unique CPX triplet repeat motif. In ileitis-prone SAMP1/YitFc mice, Paneth cell levels of CRS4C mRNAs and peptides are induced more than a 1000-fold relative to non-prone strains as early as 4 weeks of age, with the mRNA and peptide levels highest in distal ileum and below detection in duodenum. CRS4C-1 peptides are found exclusively in Paneth cells where they occur only in dense core granules and thus are secreted to function in the intestinal lumen. CRS4C bactericidal peptide activity is membrane-disruptive in that it permeabilizes Escherichia coli and induces rapid microbial cell K(+) efflux, but in a manner different from mouse alpha-defensin cryptdin-4. In in vitro studies, inactive pro-CRS4C-1 is converted to bactericidal CRS4C-1 peptide by matrix metalloproteinase-7 (MMP-7) proteolysis of the precursor proregion at the same residue positions that MMP-7 activates mouse pro-alpha-defensins. The absence of processed CRS4C in protein extracts of MMP-7-null mouse ileum demonstrates the in vivo requirement for intracellular MMP-7 in pro-CRS4C processing.

Published
2010

18. Anti-Inflammatory Effects of RTD-1 in a Murine Model of Chronic Pseudomonas aeruginosa Lung Infection: Inhibition of NF-κB, Inflammasome Gene Expression, and Pro-IL-1β Biosynthesis

Author

Mansour A. Dughbaj, Jordanna G. Jayne, A Young J. Park, Timothy J. Bensman, Marquerita Algorri, Andre J. Ouellette, Michael E. Selsted, and Paul M. Beringer

Subjects
cystic fibrosis, inflammasome, inflammation, host defense peptides, Rhesus theta defensin-1, Therapeutics. Pharmacology, RM1-950
Abstract

Vicious cycles of chronic airway obstruction, lung infections with Pseudomonas aeruginosa, and neutrophil-dominated inflammation contribute to morbidity and mortality in cystic fibrosis (CF) patients. Rhesus theta defensin-1 (RTD-1) is an antimicrobial macrocyclic peptide with immunomodulatory properties. Our objective was to investigate the anti-inflammatory effect of RTD-1 in a murine model of chronic P. aeruginosa lung infection. Mice received nebulized RTD-1 daily for 6 days. Bacterial burden, leukocyte counts, and cytokine concentrations were evaluated. Microarray analysis was performed on bronchoalveolar lavage fluid (BALF) cells and lung tissue homogenates. In vitro effects of RTD-1 in THP-1 cells were assessed using quantitative reverse transcription PCR, enzyme-linked immunosorbent assays, immunoblots, confocal microscopy, enzymatic activity assays, and NF-κB-reporter assays. RTD-1 significantly reduced lung white blood cell counts on days 3 (−54.95%; p = 0.0003) and 7 (−31.71%; p = 0.0097). Microarray analysis of lung tissue homogenates and BALF cells revealed that RTD-1 significantly reduced proinflammatory gene expression, particularly inflammasome-related genes (nod-like receptor protein 3, Mediterranean fever gene, interleukin (IL)-1α, and IL-1β) relative to the control. In vitro studies demonstrated NF–κB activation was reduced two-fold (p ≤ 0.0001) by RTD-1 treatment. Immunoblots revealed that RTD-1 treatment inhibited proIL-1β biosynthesis. Additionally, RTD-1 treatment was associated with a reduction in caspase-1 activation (FC = −1.79; p = 0.0052). RTD-1 exhibited potent anti-inflammatory activity in chronically infected mice. Importantly, RTD-1 inhibits inflammasome activity, which is possibly a downstream effect of NF-κB modulation. These findings support that this immunomodulatory peptide may be a promising therapeutic for CF-associated lung disease.

Published
2021
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19. Suppression and resolution of autoimmune arthritis by rhesus θ-defensin-1, an immunomodulatory macrocyclic peptide.

Author

Justin B Schaal, Dat Q Tran, Akshay Subramanian, Reshma Patel, Teresina Laragione, Kevin D Roberts, Katie Trinh, Prasad Tongaonkar, Patti A Tran, Dmitriy Minond, Gregg B Fields, Paul Beringer, André J Ouellette, Percio S Gulko, and Michael E Selsted

Subjects
Medicine, Science
Abstract

θ-defensins constitute a family of macrocyclic peptides expressed exclusively in Old World monkeys. The peptides are pleiotropic effectors of innate immunity, possessing broad spectrum antimicrobial activities and immunoregulatory properties. Here we report that rhesus θ-defensin 1 (RTD-1) is highly effective in arresting and reversing joint disease in a rodent model of rheumatoid arthritis (RA). Parenteral RTD-1 treatment of DA/OlaHsd rats with established pristane-induced arthritis (PIA) rapidly suppressed joint disease progression, restored limb mobility, and preserved normal joint architecture. RTD-1 significantly reduced joint IL-1β levels compared with controls. RTD-1 dose-dependently inhibited fibroblast-like synoviocyte (FLS) invasiveness and FLS IL-6 production. Consistent with the inhibition of FLS invasiveness, RTD-1 was a potent inhibitor of arthritogenic proteases including ADAMs 17 and 10 which activate TNFα, and inhibited matrix metalloproteases, and cathepsin K. RTD-1 was non-toxic, non-immunogenic, and effective when administered as infrequently as once every five days. Thus θ-defensins, which are absent in humans, have potential as retroevolutionary biologics for the treatment of RA.

Published
2017
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20. Defensins Potentiate a Neutralizing Antibody Response to Enteric Viral Infection.

Author

Anshu P Gounder, Nicolle D Myers, Piper M Treuting, Beth A Bromme, Sarah S Wilson, Mayim E Wiens, Wuyuan Lu, André J Ouellette, Katherine R Spindler, William C Parks, and Jason G Smith

Subjects
Immunologic diseases. Allergy, RC581-607, Biology (General), QH301-705.5
Abstract

α-defensins are abundant antimicrobial peptides with broad, potent antibacterial, antifungal, and antiviral activities in vitro. Although their contribution to host defense against bacteria in vivo has been demonstrated, comparable studies of their antiviral activity in vivo are lacking. Using a mouse model deficient in activated α-defensins in the small intestine, we show that Paneth cell α-defensins protect mice from oral infection by a pathogenic virus, mouse adenovirus 1 (MAdV-1). Survival differences between mouse genotypes are lost upon parenteral MAdV-1 infection, strongly implicating a role for intestinal defenses in attenuating pathogenesis. Although differences in α-defensin expression impact the composition of the ileal commensal bacterial population, depletion studies using broad-spectrum antibiotics revealed no effect of the microbiota on α-defensin-dependent viral pathogenesis. Moreover, despite the sensitivity of MAdV-1 infection to α-defensin neutralization in cell culture, we observed no barrier effect due to Paneth cell α-defensin activation on the kinetics and magnitude of MAdV-1 dissemination to the brain. Rather, a protective neutralizing antibody response was delayed in the absence of α-defensins. This effect was specific to oral viral infection, because antibody responses to parenteral or mucosal ovalbumin exposure were not affected by α-defensin deficiency. Thus, α-defensins play an important role as adjuvants in antiviral immunity in vivo that is distinct from their direct antiviral activity observed in cell culture.

Published
2016
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21. Rhesus macaque theta defensins suppress inflammatory cytokines and enhance survival in mouse models of bacteremic sepsis.

Author

Justin B Schaal, Dat Tran, Patti Tran, George Ösapay, Katie Trinh, Kevin D Roberts, Kathleen M Brasky, Prasad Tongaonkar, André J Ouellette, and Michael E Selsted

Subjects
Medicine, Science
Abstract

Theta-defensins (θ-defensins) are macrocyclic antimicrobial peptides expressed in leukocytes of Old World monkeys. The peptides are broad spectrum microbicides in vitro and numerous θ-defensin isoforms have been identified in granulocytes of rhesus macaques and Olive baboons. Several mammalian α- and β-defensins, genetically related to θ-defensins, have proinflammatory and immune-activating properties that bridge innate and acquired immunity. In the current study we analyzed the immunoregulatory properties of rhesus θ-defensins 1-5 (RTDs 1-5). RTD-1, the most abundant θ-defensin in macaques, reduced the levels of TNF, IL-1α, IL-1β, IL-6, and IL-8 secreted by blood leukocytes stimulated by several TLR agonists. RTDs 1-5 suppressed levels of soluble TNF released by bacteria- or LPS-stimulated blood leukocytes and THP-1 monocytes. Despite their highly conserved conformation and amino acid sequences, the anti-TNF activities of RTDs 1-5 varied by as much as 10-fold. Systemically administered RTD-1 was non-toxic for BALB/c mice, and escalating intravenous doses were well tolerated and non-immunogenic in adult chimpanzees. The peptide was highly stable in serum and plasma. Single dose administration of RTD-1 at 5 mg/kg significantly improved survival of BALB/c mice with E. coli peritonitis and cecal ligation-and-puncture induced polymicrobial sepsis. Peptide treatment reduced serum levels of several inflammatory cytokines/chemokines in bacteremic animals. Collectively, these results indicate that the anti-inflammatory properties of θ-defensins in vitro and in vivo are mediated by the suppression of numerous proinflammatory cytokines and blockade of TNF release may be a primary effect.

Published
2012
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