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Elkins M, Jain N, Tükel Ç. The menace within: bacterial amyloids as a trigger for autoimmune and neurodegenerative diseases. Curr Opin Microbiol 2024; 79:102473. [PMID: 38608623 PMCID: PMC11162901 DOI: 10.1016/j.mib.2024.102473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/20/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024]
Abstract
Bacteria are known to produce amyloids, proteins characterized by a conserved cross-beta sheet structure, which exhibit structural and functional similarities to human amyloids. The deposition of human amyloids into fibrillar plaques within organs is closely linked to several debilitating human diseases, including Alzheimer's and Parkinson's disease. Recently, bacterial amyloids have garnered significant attention as potential initiators of human amyloid-associated diseases as well as autoimmune diseases. This review aims to explore how bacterial amyloid, particularly curli found in gut biofilms, can act as a trigger for neurodegenerative and autoimmune diseases. We will elucidate three primary mechanisms through which bacterial amyloids exert their influence: By delving into these three distinct modes of action, this review will provide valuable insights into the intricate relationship between bacterial amyloids and the onset or progression of neurodegenerative and autoimmune diseases. A comprehensive understanding of these mechanisms may open new avenues for therapeutic interventions and preventive strategies targeting amyloid-associated diseases.
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Affiliation(s)
- Molly Elkins
- Center for Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Neha Jain
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, NH 62, Surpura Bypass, Karwar, Rajasthan, India
| | - Çagla Tükel
- Center for Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA.
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2
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Li L, Lei T, Xing C, Du H. Advances in microfluidic chips targeting toxic aggregation proteins for neurodegenerative diseases. Int J Biol Macromol 2024; 256:128308. [PMID: 37992921 DOI: 10.1016/j.ijbiomac.2023.128308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/10/2023] [Accepted: 11/19/2023] [Indexed: 11/24/2023]
Abstract
Neurodegenerative diseases (NDs) are characterized by nervous system damage, often influenced by genetic and aging factors. Pathological analysis frequently reveals the presence of aggregated toxic proteins. The intricate and poorly understood origins of these diseases have hindered progress in early diagnosis and drug development. The development of novel in-vitro and in-vivo models could enhance our comprehension of ND mechanisms and facilitate clinical treatment advancements. Microfluidic chips are employed to establish three-dimensional culture conditions, replicating the human ecological niche and creating a microenvironment conducive to neuronal cell survival. The incorporation of mechatronic controls unifies the chip, cells, and culture medium optimizing living conditions for the cells. This study provides a comprehensive overview of microfluidic chip applications in drug and biomarker screening for neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, and amyotrophic lateral sclerosis. Our Lab-on-a-Chip system releases toxic proteins to simulate the pathological characteristics of neurodegenerative diseases, encompassing β-amyloid, α-synuclein, huntingtin, TAR DNA-binding protein 43, and Myelin Basic Protein. Investigating molecular and cellular interactions in vitro can enhance our understanding of disease mechanisms while minimizing harmful protein levels and can aid in screening potential therapeutic agents. We anticipate that our research will promote the utilization of microfluidic chips in both fundamental research and clinical applications for neurodegenerative diseases.
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Affiliation(s)
- Liang Li
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Tong Lei
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Cencan Xing
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China.
| | - Hongwu Du
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China.
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3
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Oliva CA, Lira M, Jara C, Catenaccio A, Mariqueo TA, Lindsay CB, Bozinovic F, Cavieres G, Inestrosa NC, Tapia-Rojas C, Rivera DS. Long-term social isolation stress exacerbates sex-specific neurodegeneration markers in a natural model of Alzheimer's disease. Front Aging Neurosci 2023; 15:1250342. [PMID: 37810621 PMCID: PMC10557460 DOI: 10.3389/fnagi.2023.1250342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/30/2023] [Indexed: 10/10/2023] Open
Abstract
Social interactions have a significant impact on health in humans and animal models. Social isolation initiates a cascade of stress-related physiological disorders and stands as a significant risk factor for a wide spectrum of morbidity and mortality. Indeed, social isolation stress (SIS) is indicative of cognitive decline and risk to neurodegenerative conditions, including Alzheimer's disease (AD). This study aimed to evaluate the impact of chronic, long-term SIS on the propensity to develop hallmarks of AD in young degus (Octodon degus), a long-lived animal model that mimics sporadic AD naturally. We examined inflammatory factors, bioenergetic status, reactive oxygen species (ROS), oxidative stress, antioxidants, abnormal proteins, tau protein, and amyloid-β (Aβ) levels in the hippocampus of female and male degus that were socially isolated from post-natal and post-weaning until adulthood. Additionally, we explored the effect of re-socialization following chronic isolation on these protein profiles. Our results showed that SIS promotes a pro-inflammatory scenario more severe in males, a response that was partially mitigated by a period of re-socialization. In addition, ATP levels, ROS, and markers of oxidative stress are severely affected in female degus, where a period of re-socialization fails to restore them as it does in males. In females, these effects might be linked to antioxidant enzymes like catalase, which experience a decline across all SIS treatments without recovery during re-socialization. Although in males, a previous enzyme in antioxidant pathway diminishes in all treatments, catalase rebounds during re-socialization. Notably, males have less mature neurons after chronic isolation, whereas phosphorylated tau and all detectable forms of Aβ increased in both sexes, persisting even post re-socialization. Collectively, these findings suggest that long-term SIS may render males more susceptible to inflammatory states, while females are predisposed to oxidative states. In both scenarios, the accumulation of tau and Aβ proteins increase the individual susceptibility to early-onset neurodegenerative conditions such as AD.
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Affiliation(s)
- Carolina A. Oliva
- Centro para la Transversalización de Género en I+D+i+e, Vicerrectoría de Investigación y Doctorados, Universidad Autónoma de Chile, Santiago, Chile
| | - Matías Lira
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago, Chile
| | - Claudia Jara
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - Alejandra Catenaccio
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago, Chile
| | - Trinidad A. Mariqueo
- Centro de Investigaciones Médicas, Laboratorio de Neurofarmacología, Escuela de Medicina, Universidad de Talca, Talca, Chile
| | - Carolina B. Lindsay
- Laboratory of Neurosystems, Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Francisco Bozinovic
- Center of Applied Ecology and Sustainability (CAPES), Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Grisel Cavieres
- Center of Applied Ecology and Sustainability (CAPES), Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Zoología, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Chile
| | - Nibaldo C. Inestrosa
- Center of Aging and Regeneration UC (CARE-UC), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
| | - Cheril Tapia-Rojas
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago, Chile
| | - Daniela S. Rivera
- GEMA Center for Genomics, Ecology and Environment, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago, Chile
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4
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Living with the enemy: from protein-misfolding pathologies we know, to those we want to know. Ageing Res Rev 2021; 70:101391. [PMID: 34119687 DOI: 10.1016/j.arr.2021.101391] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/19/2021] [Accepted: 06/09/2021] [Indexed: 12/12/2022]
Abstract
Conformational diseases are caused by the aggregation of misfolded proteins. The risk for such pathologies develops years before clinical symptoms appear, and is higher in people with alpha-1 antitrypsin (AAT) polymorphisms. Thousands of people with alpha-1 antitrypsin deficiency (AATD) are underdiagnosed. Enemy-aggregating proteins may reside in these underdiagnosed AATD patients for many years before a pathology for AATD fully develops. In this perspective review, we hypothesize that the AAT protein could exert a new and previously unconsidered biological effect as an endogenous metal ion chelator that plays a significant role in essential metal ion homeostasis. In this respect, AAT polymorphism may cause an imbalance of metal ions, which could be correlated with the aggregation of amylin, tau, amyloid beta, and alpha synuclein proteins in type 2 diabetes mellitus (T2DM), Alzheimer's and Parkinson's diseases, respectively.
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5
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Lechauve C, Keith J, Khandros E, Fowler S, Mayberry K, Freiwan A, Thom CS, Delbini P, Romero EB, Zhang J, Motta I, Tillman H, Cappellini MD, Kundu M, Weiss MJ. The autophagy-activating kinase ULK1 mediates clearance of free α-globin in β-thalassemia. Sci Transl Med 2020; 11:11/506/eaav4881. [PMID: 31434755 DOI: 10.1126/scitranslmed.aav4881] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 03/26/2019] [Accepted: 07/18/2019] [Indexed: 12/15/2022]
Abstract
In β-thalassemia, accumulated free α-globin forms intracellular precipitates that impair erythroid cell maturation and viability. Protein quality control systems mitigate β-thalassemia pathophysiology by degrading toxic free α-globin, although the associated mechanisms are poorly understood. We show that loss of the autophagy-activating Unc-51-like kinase 1 (Ulk1) gene in β-thalassemic mice reduces autophagic clearance of α-globin in red blood cell precursors and exacerbates disease phenotypes, whereas inactivation of the canonical autophagy-related 5 (Atg5) gene has relatively minor effects. Systemic treatment with the mTORC1 inhibitor rapamycin reduces α-globin precipitates and lessens pathologies in β-thalassemic mice via an ULK1-dependent pathway. Similarly, rapamycin reduces free α-globin accumulation in erythroblasts derived from CD34+ cells of β-thalassemic individuals. Our findings define a drug-regulatable pathway for ameliorating β-thalassemia.
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Affiliation(s)
- Christophe Lechauve
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Julia Keith
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Eugene Khandros
- Department of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Stephanie Fowler
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Kalin Mayberry
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Abdullah Freiwan
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Christopher S Thom
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Paola Delbini
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
| | - Emilio Boada Romero
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jingjing Zhang
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Irene Motta
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
| | - Heather Tillman
- Departments of Pathology and Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - M Domenica Cappellini
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
| | - Mondira Kundu
- Departments of Pathology and Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Mitchell J Weiss
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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6
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Brändli-Baiocco A, Balme E, Bruder M, Chandra S, Hellmann J, Hoenerhoff MJ, Kambara T, Landes C, Lenz B, Mense M, Rittinghausen S, Satoh H, Schorsch F, Seeliger F, Tanaka T, Tsuchitani M, Wojcinski Z, Rosol TJ. Nonproliferative and Proliferative Lesions of the Rat and Mouse Endocrine System. J Toxicol Pathol 2018; 31:1S-95S. [PMID: 30158740 PMCID: PMC6108091 DOI: 10.1293/tox.31.1s] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for
Lesions in Rats and Mice) Project (www.toxpath.org/inhand.asp) is a joint initiative among
the Societies of Toxicological Pathology from Europe (ESTP), Great Britain (BSTP), Japan
(JSTP) and North America (STP) to develop an internationally accepted nomenclature for
proliferative and nonproliferative lesions in laboratory animals. The purpose of this
publication is to provide a standardized nomenclature for classifying microscopic lesions
observed in the endocrine organs (pituitary gland, pineal gland, thyroid gland,
parathyroid glands, adrenal glands and pancreatic islets) of laboratory rats and mice,
with color photomicrographs illustrating examples of the lesions. The standardized
nomenclature presented in this document is also available electronically on the internet
(http://www.goreni.org/). Sources of material included histopathology databases from
government, academia, and industrial laboratories throughout the world. Content includes
spontaneous and aging lesions as well as lesions induced by exposure to test materials. A
widely accepted and utilized international harmonization of nomenclature for endocrine
lesions in laboratory animals will decrease confusion among regulatory and scientific
research organizations in different countries and provide a common language to increase
and enrich international exchanges of information among toxicologists and
pathologists.
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Affiliation(s)
- Annamaria Brändli-Baiocco
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
| | | | - Marc Bruder
- Compugen, Inc., Nonclinical Safety, South San Francisco, California, USA
| | | | | | - Mark J Hoenerhoff
- In Vivo Animal Core, Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, Michigan USA
| | | | - Christian Landes
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
| | - Barbara Lenz
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center, Basel, Switzerland
| | | | | | - Hiroshi Satoh
- Iwate University, Faculty of Agriculture, Iwate, Japan
| | | | - Frank Seeliger
- AstraZeneca Pathology, Drug Safety and Metabolism, IMED Biotech Unit, Gothenburg, Sweden
| | - Takuji Tanaka
- Tohkai Cytopathology Institute, Cancer Research and Prevention, Gifu, Japan
| | - Minoru Tsuchitani
- LSI Medience Corporation, Nonclinical Research Center, Ibaraki, Japan
| | | | - Thomas J Rosol
- Ohio University, Department of Biomedical Sciences, Athens, Ohio, USA
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7
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Brüning A, Jückstock J. Misfolded proteins: from little villains to little helpers in the fight against cancer. Front Oncol 2015; 5:47. [PMID: 25759792 PMCID: PMC4338749 DOI: 10.3389/fonc.2015.00047] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 02/11/2015] [Indexed: 12/15/2022] Open
Abstract
The application of cytostatic drugs targeting the high proliferation rates of cancer cells is currently the most commonly used treatment option in cancer chemotherapy. However, severe side effects and resistance mechanisms may occur as a result of such treatment, possibly limiting the therapeutic efficacy of these agents. In recent years, several therapeutic strategies have been developed that aim at targeting not the genomic integrity and replication machinery of cancer cells but instead their protein homeostasis. During malignant transformation, the cancer cell proteome develops vast aberrations in the expression of mutated proteins, oncoproteins, drug- and apoptosis-resistance proteins, etc. A complex network of protein quality-control mechanisms, including chaperoning by heat shock proteins (HSPs), not only is essential for maintaining the extravagant proteomic lifestyle of cancer cells but also represents an ideal cancer-specific target to be tackled. Furthermore, the high rate of protein synthesis and turnover in certain types of cancer cells can be specifically directed by interfering with the proteasomal and autophagosomal protein recycling and degradation machinery, as evidenced by the clinical application of proteasome inhibitors. Since proteins with loss of their native conformation are prone to unspecific aggregations and have proved to be detrimental to normal cellular function, specific induction of misfolded proteins by HSP inhibitors, proteasome inhibitors, hyperthermia, or inducers of endoplasmic reticulum stress represents a new method of cancer cell killing exploitable for therapeutic purposes. This review describes drugs - approved, repurposed, or under investigation - that can be used to accumulate misfolded proteins in cancer cells, and particularly focuses on the molecular aspects that lead to the cytotoxicity of misfolded proteins in cancer cells.
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Affiliation(s)
- Ansgar Brüning
- Molecular Biology Laboratory, Ludwig-Maximilians-University , Munich , Germany
| | - Julia Jückstock
- Molecular Biology Laboratory, Ludwig-Maximilians-University , Munich , Germany
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8
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Rapsinski GJ, Newman TN, Oppong GO, van Putten JPM, Tükel Ç. CD14 protein acts as an adaptor molecule for the immune recognition of Salmonella curli fibers. J Biol Chem 2013; 288:14178-14188. [PMID: 23548899 DOI: 10.1074/jbc.m112.447060] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Amyloids, protein aggregates with a cross β-sheet structure, contribute to inflammation in debilitating disorders, including Alzheimer's disease. Enteric bacteria also produce amyloids, termed curli, contributing to inflammation during infection. It has been demonstrated that curli and β-amyloid are recognized by the immune system via the Toll-like receptor (TLR) 2/TLR1 complex. Here we investigated the role of CD14 in the immune recognition of bacterial amyloids. We used HeLa 57A cells, a human cervical cancer cell line containing a luciferase reporter gene under the control of an NF-κB promoter. When HeLa 57A cells were transiently transfected with combinations of human expression vectors containing genes for TLR2, TLR1, and CD14, membrane-bound CD14 enhanced NF-κB activation through the TLR2/TLR1 complex stimulated with curli fibers or recombinant CsgA, the curli major subunit. Similarly, soluble CD14 augmented the TLR2/TLR1 response to curli fibers in the absence of membrane-bound CD14. We further revealed that IL-6 and nitric oxide production were significantly higher by wild-type (C57BL/6) bone marrow-derived macrophages compared with TLR2-deficient or CD14-deficient bone marrow-derived macrophages when stimulated with curli fibers, recombinant CsgA, or synthetic CsgA peptide, CsgA-R4-5. Binding assays demonstrated that recombinant TLR2, TLR1, and CD14 bound purified curli fibers. Interestingly, CD14-curli interaction was specific to the fibrillar form of the amyloid, as demonstrated by using synthetic CsgA peptides proficient and deficient in fiber formation, respectively. Activation of the TLR2/TLR1/CD14 trimolecular complex by amyloids provides novel insights for innate immunity with implications for amyloid-associated diseases.
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Affiliation(s)
- Glenn J Rapsinski
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140
| | - Tiffanny N Newman
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140
| | - Gertrude O Oppong
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140
| | - Jos P M van Putten
- Department of Infectious Diseases and Immunology, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands
| | - Çagla Tükel
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140.
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Epithelial cells augment barrier function via activation of the Toll-like receptor 2/phosphatidylinositol 3-kinase pathway upon recognition of Salmonella enterica serovar Typhimurium curli fibrils in the gut. Infect Immun 2012. [PMID: 23208603 DOI: 10.1128/iai.00453-12] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Curli fibrils, the best-characterized functional bacterial amyloids, are an important component of enterobacterial biofilms. We have previously shown that curli fibrils are recognized by the Toll-like receptor 2 (TLR2)/TLR1 heterodimer complex. Utilizing polarized T-84 cells, an intestinal epithelial cell line derived from colon carcinoma grown on semipermeable tissue culture inserts, we determined that infection with a Salmonella enterica serovar Typhimurium csgBA mutant, which does not express curli, resulted in an increase in intestinal barrier permeability and an increase in bacterial translocation compared to infection with curliated wild-type S. Typhimurium. When the TLR2 downstream signaling molecule phosphatidylinositol 3-kinase (PI3K) was blocked using wortmannin or LY294002, the difference in disruption of the intestinal epithelium and bacterial translocation was no longer observed. Additionally, disruption of polarized T-84 cells treated basolaterally with the TLR5 ligand flagellin was prevented when the polarized cells were simultaneously treated with the synthetic TLR2/TLR1 ligand Pam(3)CSK(4) or with purified curli fibrils in the apical compartment. Similar to in vitro observations, C57BL/6 mice infected with the csgBA mutant suffered increased disruption of the intestinal epithelium and therefore greater dissemination of the bacteria to the mesenteric lymph nodes than mice infected with wild-type S. Typhimurium. The differences in disruption of the intestinal epithelium and bacterial dissemination in the mice infected with csgBA mutant or wild-type S. Typhimurium were not apparent in TLR2-deficient mice. Overall, these studies report for the first time that activation of the TLR2/PI3K pathway by microbial amyloids plays a critical role in regulating the intestinal epithelial barrier as well as monitoring bacterial translocation during infection.
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10
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van Echten-Deckert G, Walter J. Sphingolipids: Critical players in Alzheimer’s disease. Prog Lipid Res 2012; 51:378-93. [DOI: 10.1016/j.plipres.2012.07.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 07/06/2012] [Indexed: 12/20/2022]
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Abstract
Erythrocytes must regulate hemoglobin synthesis to limit the toxicities of unstable free globin chain subunits. This regulation is particularly relevant in β-thalassemia, in which β-globin deficiency causes accumulation of free α-globin, which forms intracellular precipitates that destroy erythroid precursors. Experimental evidence accumulated over more than 40 years indicates that erythroid cells can neutralize moderate amounts of free α-globin through generalized protein quality control mechanisms, including molecular chaperones, the ubiquitin-proteasome system, and autophagy. In many ways, β-thalassemia resembles protein aggregation disorders of the nervous system, liver, and other tissues, which occur when levels of unstable proteins overwhelm cellular compensatory mechanisms. Information gained from studies of nonerythroid protein aggregation disorders may be exploited to further understand and perhaps treat β-thalassemia.
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12
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Thoolen B, Maronpot RR, Harada T, Nyska A, Rousseaux C, Nolte T, Malarkey DE, Kaufmann W, Küttler K, Deschl U, Nakae D, Gregson R, Vinlove MP, Brix AE, Singh B, Belpoggi F, Ward JM. Proliferative and nonproliferative lesions of the rat and mouse hepatobiliary system. Toxicol Pathol 2011; 38:5S-81S. [PMID: 21191096 DOI: 10.1177/0192623310386499] [Citation(s) in RCA: 398] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally-accepted nomenclature for proliferative and non-proliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature and differential diagnosis for classifying microscopic lesions observed in the hepatobiliary system of laboratory rats and mice, with color microphotographs illustrating examples of some lesions. The standardized nomenclature presented in this document is also available for society members electronically on the internet (http://goreni.org). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous and aging lesions as well as lesions induced by exposure to test materials. A widely accepted and utilized international harmonization of nomenclature for lesions of the hepatobiliary system in laboratory animals will decrease confusion among regulatory and scientific research organizations in different countries and provide a common language to increase and enrich international exchanges of information among toxicologists and pathologists.
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Affiliation(s)
- Bob Thoolen
- Global Pathology Support, The Hague, The Netherlands.
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13
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Distribution of lithostathine in the mouse lemur brain with aging and Alzheimer's-like pathology. Neurobiol Aging 2011; 33:431.e15-25. [PMID: 21371784 DOI: 10.1016/j.neurobiolaging.2011.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 12/16/2010] [Accepted: 01/06/2011] [Indexed: 02/01/2023]
Abstract
We analyzed the cellular distribution of the pancreatic inflammatory protein lithostathine and its receptor EXTL3 in the brain of the lemurian primate Microcebus murinus which develops amyloid deposits along with aging. In adult animals (2-4.5 years old), lithostathine and EXTL3 immunoreactivities were largely distributed in the whole brain, and more intensively in almost all cortical layers and hippocampal formation. Lithostathine was observed in the perikarya and neurites of cortical neurons but also in glial cells in the border of the ventricle and the corpus callosum. In healthy aged animals (8-13 years old), highest densities of lithostathine-containing cells were observed, mainly in occipital and parietal cortex. In aged animals with Aβ deposits, the increase in lithostathine immunoreactivity was lower as compared with aged animals. Noteworthy, lithostathine-immunopositive cells did almost never colocalize with Aβ plaques. In conclusion, lithostathine immunoreactivity in adult Microcebus murinus appeared ubiquitous and particularly in visual, sensorial, and cognitive brain areas. Immunoreactivity increased with aging and appeared markedly affected in neuropathological conditions. Its possible neuroprotection or neurodegeneration role in Alzheimer pathology deserves therefore to be investigated.
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