51
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Leeder WM, Giehler F, Joswig J, Göringer HU. Bioinspired Design of Lysolytic Triterpenoid-Peptide Conjugates that Kill African Trypanosomes. Chembiochem 2019; 20:1251-1255. [PMID: 30609206 DOI: 10.1002/cbic.201800674] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/19/2018] [Indexed: 11/07/2022]
Abstract
Humans have evolved a natural immunity against Trypanosoma brucei infections, which is executed by two serum (lipo)protein complexes known as trypanolytic factors (TLF). The active TLF ingredient is the primate-specific apolipoprotein L1 (APOL1). The protein has a pore-forming activity that kills parasites by lysosomal and mitochondrial membrane fenestration. Of the many trypanosome subspecies, only two are able to counteract the activity of APOL1; this illustrates its evolutionarily optimized design and trypanocidal potency. Herein, we ask whether a synthetic (syn) TLF can be synthesized by using the design principles of the natural TLF complexes but with different chemical building blocks. We demonstrate the stepwise development of triterpenoid-peptide conjugates, in which the triterpenoids act as a cell-binding, uptake and lysosomal-transport modules and the synthetic peptide GALA acts as a pH-sensitive, pore-forming lysolytic toxin. As designed, the conjugate kills infective-stage African trypanosomes through lysosomal lysis thus demonstrating a proof-of-principle for the bioinspired, forward-design of a synTLF.
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Affiliation(s)
- W-Matthias Leeder
- Molecular Genetics, Darmstadt University of Technology, Schnittspahnstrasse 10, 64287, Darmstadt, Germany
| | - Fabian Giehler
- Molecular Genetics, Darmstadt University of Technology, Schnittspahnstrasse 10, 64287, Darmstadt, Germany.,Present address: Helmholtz Zentrum München für Gesundheit und Umwelt (GmbH), Research Unit Gene Vectors Munich (Germany) and, German Center for Infection Research (DZIF), Partner Site Munich, Marchionistrasse 25, 81377, Munich, Germany
| | - Juliane Joswig
- Molecular Genetics, Darmstadt University of Technology, Schnittspahnstrasse 10, 64287, Darmstadt, Germany
| | - H Ulrich Göringer
- Molecular Genetics, Darmstadt University of Technology, Schnittspahnstrasse 10, 64287, Darmstadt, Germany
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52
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DiMaio J, Ruthel G, Cannon JJ, Malfara MF, Povelones ML. The single mitochondrion of the kinetoplastid parasite Crithidia fasciculata is a dynamic network. PLoS One 2018; 13:e0202711. [PMID: 30592713 PMCID: PMC6310254 DOI: 10.1371/journal.pone.0202711] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 12/11/2018] [Indexed: 11/18/2022] Open
Abstract
Mitochondria are central organelles in cellular metabolism. Their structure is highly dynamic, allowing them to adapt to different energy requirements, to be partitioned during cell division, and to maintain functionality. Mitochondrial dynamics, including membrane fusion and fission reactions, are well studied in yeast and mammals but it is not known if these processes are conserved throughout eukaryotic evolution. Kinetoplastid parasites are some of the earliest-diverging eukaryotes to retain a mitochondrion. Each cell has only a single mitochondrial organelle, making them an interesting model for the role of dynamics in controlling mitochondrial architecture. We have investigated the mitochondrial division cycle in the kinetoplastid Crithidia fasciculata. The majority of mitochondrial biogenesis occurs during the G1 phase of the cell cycle, and the mitochondrion is divided symmetrically in a process coincident with cytokinesis. Live cell imaging revealed that the mitochondrion is highly dynamic, with frequent changes in the topology of the branched network. These remodeling reactions include tubule fission, fusion, and sliding, as well as new tubule formation. We hypothesize that the function of this dynamic remodeling is to homogenize mitochondrial contents and to facilitate rapid transport of mitochondria-encoded gene products from the area containing the mitochondrial nucleoid to other parts of the organelle.
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Affiliation(s)
- John DiMaio
- Sciences Division, Brandywine Campus, The Pennsylvania State University, Media, Pennsylvania, United States of America
| | - Gordon Ruthel
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Joshua J. Cannon
- Sciences Division, Brandywine Campus, The Pennsylvania State University, Media, Pennsylvania, United States of America
| | - Madeline F. Malfara
- Sciences Division, Brandywine Campus, The Pennsylvania State University, Media, Pennsylvania, United States of America
| | - Megan L. Povelones
- Sciences Division, Brandywine Campus, The Pennsylvania State University, Media, Pennsylvania, United States of America
- * E-mail:
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53
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Nganga R, Oleinik N, Kim J, Selvam SP, De Palma R, Johnson KA, Parikh RY, Gangaraju V, Peterson Y, Dany M, Stahelin RV, Voelkel-Johnson C, Szulc ZM, Bieberich E, Ogretmen B. Receptor-interacting Ser/Thr kinase 1 (RIPK1) and myosin IIA-dependent ceramidosomes form membrane pores that mediate blebbing and necroptosis. J Biol Chem 2018; 294:502-519. [PMID: 30420430 DOI: 10.1074/jbc.ra118.005865] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/08/2018] [Indexed: 12/29/2022] Open
Abstract
Formation of membrane pores/channels regulates various cellular processes, such as necroptosis or stem cell niche signaling. However, the roles of membrane lipids in the formation of pores and their biological functions are largely unknown. Here, using the cellular stress model evoked by the sphingolipid analog drug FTY720, we show that formation of ceramide-enriched membrane pores, referred to here as ceramidosomes, is initiated by a receptor-interacting Ser/Thr kinase 1 (RIPK1)-ceramide complex transported to the plasma membrane by nonmuscle myosin IIA-dependent trafficking in human lung cancer cells. Molecular modeling/simulation coupled with site-directed mutagenesis revealed that Asp147 or Asn169 of RIPK1 are key for ceramide binding and that Arg258 or Leu293 residues are involved in the myosin IIA interaction, leading to ceramidosome formation and necroptosis. Moreover, generation of ceramidosomes independently of any external drug/stress stimuli was also detected in the plasma membrane of germ line stem cells in ovaries during the early stages of oogenesis in Drosophila melanogaster Inhibition of ceramidosome formation via myosin IIA silencing limited germ line stem cell signaling and abrogated oogenesis. In conclusion, our findings indicate that the RIPK1-ceramide complex forms large membrane pores we named ceramidosomes. They further suggest that, in addition to their roles in stress-mediated necroptosis, these ceramide-enriched pores also regulate membrane integrity and signaling and might also play a role in D. melanogaster ovary development.
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Affiliation(s)
- Rose Nganga
- From the Department of Biochemistry and Molecular Biology and.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Natalia Oleinik
- From the Department of Biochemistry and Molecular Biology and.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Jisun Kim
- From the Department of Biochemistry and Molecular Biology and.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Shanmugam Panneer Selvam
- From the Department of Biochemistry and Molecular Biology and.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Ryan De Palma
- From the Department of Biochemistry and Molecular Biology and.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kristen A Johnson
- Department of Chemistry and Biochemistry, University of Notre Dame, South Bend, Indiana, 46617
| | - Rasesh Y Parikh
- From the Department of Biochemistry and Molecular Biology and
| | - Vamsi Gangaraju
- From the Department of Biochemistry and Molecular Biology and
| | - Yuri Peterson
- the College of Pharmacy/Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, 29425
| | - Mohammed Dany
- From the Department of Biochemistry and Molecular Biology and.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Robert V Stahelin
- the Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907
| | | | | | - Erhard Bieberich
- the Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, Georgia 30912, and.,the Department of Physiology, University of Kentucky, Lexington, Kentucky 40506
| | - Besim Ogretmen
- From the Department of Biochemistry and Molecular Biology and .,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
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54
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Radwanska M, Vereecke N, Deleeuw V, Pinto J, Magez S. Salivarian Trypanosomosis: A Review of Parasites Involved, Their Global Distribution and Their Interaction With the Innate and Adaptive Mammalian Host Immune System. Front Immunol 2018; 9:2253. [PMID: 30333827 PMCID: PMC6175991 DOI: 10.3389/fimmu.2018.02253] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/11/2018] [Indexed: 01/27/2023] Open
Abstract
Salivarian trypanosomes are single cell extracellular parasites that cause infections in a wide range of hosts. Most pathogenic infections worldwide are caused by one of four major species of trypanosomes including (i) Trypanosoma brucei and the human infective subspecies T. b. gambiense and T. b. rhodesiense, (ii) Trypanosoma evansi and T. equiperdum, (iii) Trypanosoma congolense and (iv) Trypanosoma vivax. Infections with these parasites are marked by excessive immune dysfunction and immunopathology, both related to prolonged inflammatory host immune responses. Here we review the classification and global distribution of these parasites, highlight the adaptation of human infective trypanosomes that allow them to survive innate defense molecules unique to man, gorilla, and baboon serum and refer to the discovery of sexual reproduction of trypanosomes in the tsetse vector. With respect to the immunology of mammalian host-parasite interactions, the review highlights recent findings with respect to the B cell destruction capacity of trypanosomes and the role of T cells in the governance of infection control. Understanding infection-associated dysfunction and regulation of both these immune compartments is crucial to explain the continued failures of anti-trypanosome vaccine developments as well as the lack of any field-applicable vaccine based anti-trypanosomosis intervention strategy. Finally, the link between infection-associated inflammation and trypanosomosis induced anemia is covered in the context of both livestock and human infections.
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Affiliation(s)
- Magdalena Radwanska
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
| | - Nick Vereecke
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea.,Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Violette Deleeuw
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Joar Pinto
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Stefan Magez
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea.,Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
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55
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Baek JH, Gomez IG, Wada Y, Roach A, Mahad D, Duffield JS. Deletion of the Mitochondrial Complex-IV Cofactor Heme A:Farnesyltransferase Causes Focal Segmental Glomerulosclerosis and Interferon Response. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 188:2745-2762. [PMID: 30268775 DOI: 10.1016/j.ajpath.2018.08.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/02/2018] [Accepted: 08/06/2018] [Indexed: 01/31/2023]
Abstract
Mutations in mitochondrial DNA as well as nuclear-encoded mitochondrial proteins have been reported to cause tubulointerstitial kidney diseases and focal segmental glomerulosclerosis (FSGS). Recently, genes and pathways affecting mitochondrial turnover and permeability have been implicated in adult-onset FSGS. Furthermore, dysfunctioning mitochondria may be capable of engaging intracellular innate immune-sensing pathways. To determine the impact of mitochondrial dysfunction in FSGS and secondary innate immune responses, we generated Cre/loxP transgenic mice to generate a loss-of-function deletion mutation of the complex IV assembly cofactor heme A:farnesyltransferase (COX10) restricted to cells of the developing nephrons. These mice develop severe, early-onset FSGS with innate immune activation and die prematurely with kidney failure. Mutant kidneys showed loss of glomerular and tubular epithelial function, epithelial apoptosis, and, in addition, a marked interferon response. In vitro modeling of Cox10 deletion in primary kidney epithelium compromises oxygen consumption, ATP generation, and induces oxidative stress. In addition, loss of Cox10 triggers a selective interferon response, which may be caused by the leak of mitochondrial DNA into the cytosol activating the intracellular DNA sensor, stimulator of interferon genes. This new animal model provides a mechanism to study mitochondrial dysfunction in vivo and demonstrates a direct link between mitochondrial dysfunction and intracellular innate immune response.
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Affiliation(s)
- Jea-Hyun Baek
- Research and Development, Biogen Inc., Cambridge, Massachusetts.
| | - Ivan G Gomez
- Research and Development, Biogen Inc., Cambridge, Massachusetts; Division of Nephrology, Departments of Medicine and Pathology, University of Washington, Seattle, Washington
| | - Yukihiro Wada
- Division of Nephrology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan
| | - Allie Roach
- Research and Development, Biogen Inc., Cambridge, Massachusetts; Division of Nephrology, Departments of Medicine and Pathology, University of Washington, Seattle, Washington
| | - Don Mahad
- Centre for Clinical Brain Sciences, Anne Rowling Regenerative Neurology Clinic and Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
| | - Jeremy S Duffield
- Research and Development, Biogen Inc., Cambridge, Massachusetts; Division of Nephrology, Departments of Medicine and Pathology, University of Washington, Seattle, Washington; Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts.
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56
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Abstract
Apolipoprotein L1 (APOL1) protein is the human serum factor that protect human beings against Trypanosoma brucei brucei, the cause of trypanosomiasis. Subspecies of T b brucei that cause human sleeping sickness-T b gambiense and T b rhodesiense evolved molecular mechanisms that enabled them to evade killing by APOL1. Sequence changes (termed G1 and G2) in the APOL1 gene that restored its ability to kill T b rhodesiense also increase the risk of developing glomerular diseases and accelerate progression to end-stage kidney disease. To lyse trypanosome parasites, APOL1 forms pores in the trypanosome endolysosomal and mitochondrial membranes, resulting in rapid membrane depolarization. However, the molecular mechanism underlying APOL1 nephropathy is unknown. Recent experimental evidence has shown that aberrant efflux of intracellular potassium is an early event in APOL1-induced death of human embryonic kidney cells. Here, we discuss the possibility that abnormal efflux of cellular potassium or other cations may be relevant to the pathogenesis of APOL1 nephropathy.
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Affiliation(s)
- Opeyemi A Olabisi
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Boston, MA; Harvard Medical School, Boston, MA.
| | - John F Heneghan
- Harvard Medical School, Boston, MA; Division of Nephrology, Vascular Biology Research Center, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA; Surgical Immunotherapy at Roger Williams Medical Center, Providence, RI
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57
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Abstract
The association of variants in the APOL1 gene, which encodes apolipoprotein L1 (APOL1), with progressive nondiabetic kidney diseases in African Americans has prompted intense investigation into the function(s) of APOL1. APOL1 is an innate immune effector that protects human beings from infection by some trypanosomal parasites. We review the data characterizing APOL1 trypanolytic function, which has been a basis for studies of APOL1 function in mammalian cells. Subsequently, we discuss the studies that use animal models, mammalian cell culture models, and kidney biopsy tissue to discover the mechanisms of variant APOL1-associated kidney diseases.
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58
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Cheatham AM, Davis SE, Khatua AK, Popik W. Blocking the 5' splice site of exon 4 by a morpholino oligomer triggers APOL1 protein isoform switch. Sci Rep 2018; 8:8739. [PMID: 29880816 PMCID: PMC5992166 DOI: 10.1038/s41598-018-27104-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 05/21/2018] [Indexed: 12/16/2022] Open
Abstract
APOL1 risk alleles G1 or G2 are associated with a kidney disease phenotype exclusively in people of recent African ancestry. Here we show that exon 4 encoding a part of the APOL1 signal peptide is constitutively spliced in major APOL1 transcripts expressed in kidney glomerular and tubular cells. We demonstrate that constitutive splicing of exon 4 results from a suboptimal hnRNP A1 binding motif found in exon 4. Accordingly, a robust binding of hnRNP A1 protein to a consensus hnRNP A1 cis-acting element in exon 4 results in almost complete exclusion of exon 4 from the APOL1 minigene transcripts. Blocking the 5' splice site at the exon 4/intron boundary with a specific antisense morpholino oligonucleotide excludes exon 4 from the splicing pattern of endogenous APOL1 transcripts. These transcripts are fully functional and produce APOL1 protein isoform that is not normally detectable in podocytes. Together with our previous data showing no cytotoxicity of overexpressed APOL1 isoform lacking exon 4, we propose that morpholino-induced APOL1 isoform switch may provide a new tool to identify in vivo molecular mechanism(s) by which risk alleles promote or mediate the kidney disease phenotype.
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Affiliation(s)
- Amber M Cheatham
- Meharry Medical College, Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, 1005 D. B. Todd Blvd, Nashville, TN, 37028, USA
| | - Shamara E Davis
- Meharry Medical College, Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, 1005 D. B. Todd Blvd, Nashville, TN, 37028, USA
| | - Atanu K Khatua
- Meharry Medical College, Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, 1005 D. B. Todd Blvd, Nashville, TN, 37028, USA
| | - Waldemar Popik
- Meharry Medical College, Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, 1005 D. B. Todd Blvd, Nashville, TN, 37028, USA.
- Department of Internal Medicine, 1005 D. B. Todd Blvd, Nashville, TN, 37028, USA.
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59
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APOL1: The Balance Imposed by Infection, Selection, and Kidney Disease. Trends Mol Med 2018; 24:682-695. [PMID: 29886044 DOI: 10.1016/j.molmed.2018.05.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 05/07/2018] [Accepted: 05/14/2018] [Indexed: 02/07/2023]
Abstract
Chronic kidney disease (CKD) affects millions of people and constitutes a major health and financial burden worldwide. People of African descent are at an increased risk of developing kidney disease, which is mostly explained by two variants in the Apolipoprotein L1 (APOL1) gene that are found only in people of west African origin. It is hypothesized that these variants were genetically selected due to the protection they afford against African sleeping sickness, caused by the parasite Trypanosoma brucei. Targeting mutant APOL1 could have substantial therapeutic potential for treating kidney disease. In this review, we will describe the intriguing interplay between microbiology, genetics, and kidney disease as revealed in APOL1-associated kidney disease, discuss APOL1-induced cytotoxicity and its therapeutic implications.
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60
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Yuan D, Liu C, Hu B. Dysfunction of Membrane Trafficking Leads to Ischemia-Reperfusion Injury After Transient Cerebral Ischemia. Transl Stroke Res 2018; 9:215-222. [PMID: 29022237 PMCID: PMC5895539 DOI: 10.1007/s12975-017-0572-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 01/12/2023]
Abstract
Neurons require an extraordinarily high level of membrane trafficking activities because of enriched axonal terminals and dendritic branches. For that reason, defects in the membrane trafficking pathway are a hallmark of most, and may be all, neurodegenerative disorders. A major cellular membrane trafficking pathway is the Golgi apparatus (Golgi hereafter)-late endosome-lysosome axis for supplying lysosomal enzymes. This pathway is regulated by N-ethylmaleimide-sensitive factor (NSF) ATPase. This review article is to discuss a novel hypothesis that brain ischemia inactivates NSF ATPase, resulting in a cascade of events of disruption of the Golgi-endosome-lysosome pathway, release of cathepsin B (CTSB), and induction of mitochondrial outer membrane permeabilization (MOMP) during the postischemic phase. This hypothesis is supported by recent studies demonstrating that NSF is trapped into inactive protein aggregates in neurons destined to die after brain ischemia. Consequently, Golgi, transport vesicles (TVs), and late endosomes (LEs) are accumulated and damaged, which is followed by CTSB release from these damaged structures. Moderate release of CTSB cleaves Bax-like BH3 protein (Bid) to become active truncated Bid (tBid). Active tBid is then translocated to the mitochondrial outer membrane, resulting in oligomerization of BCL2-associated X protein (Bax) forming the mitochondrial outer membrane pores, and releasing mitochondrial intramembranous proteins. Extensive CTSB release, however, can digest cellular proteins indiscriminately to induce cell death. Based on these new observations, we propose a novel hypothesis, i.e., brain ischemia leads to NSF inactivation, resulting in a massive buildup of damaged Golgi, TVs and LEs, fatal release of CTSB, induction of MOMP, and eventually brain ischemia-reperfusion injury.
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Affiliation(s)
- Dong Yuan
- Department of Anesthesiology and Neurology, Shock Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Chunli Liu
- Department of Anesthesiology and Neurology, Shock Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Bingren Hu
- Department of Anesthesiology and Neurology, Shock Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Veterans Affairs Maryland Health Center System, 10 North Greene Street, Baltimore, MD, 21201, USA.
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61
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Reidy KJ, Hjorten R, Parekh RS. Genetic risk of APOL1 and kidney disease in children and young adults of African ancestry. Curr Opin Pediatr 2018; 30:252-259. [PMID: 29406442 PMCID: PMC6002812 DOI: 10.1097/mop.0000000000000603] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE OF REVIEW Understanding the genetic risk of APOL1 in children and young adults is important given the lifetime risk of hypertension and kidney disease among children of African descent. We review recent epidemiologic and biologic findings on the effects of APOL1 and kidney disease. RECENT FINDINGS APOL1 in children and young adults is associated with hypertension, albuminuria and more rapid decline in kidney function and progression to end-stage kidney disease, especially among those with glomerular causes of kidney disease, and those affected by sickle cell disease or HIV. There are conflicting data on the APOL1 association with cardiovascular disease in children and young adults. APOL1 functions as part of the innate immune system. Podocyte expression of APOL1 likely contributes to the development of kidney disease. In cell culture and model organisms, APOL1 expression disrupts autophagic and ion flux, leads to defects in mitochondrial respiration and induces cell death. SUMMARY APOL1 explains almost 70% of the excess risk of kidney disease in those of African descent, and is common in children with glomerular disease. An evolving understanding of the pathogenesis of APOL1-mediated kidney damage may aid in personalized medicine approaches to APOL1 attributable kidney disease.
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Affiliation(s)
- Kimberly J Reidy
- Children’s Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Rebecca Hjorten
- Children’s Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center
| | - Rulan S. Parekh
- Departments of Pediatrics and Medicine, Hospital for Sick Children, University Health Network and University of Toronto, Toronto, Canada
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62
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Affiliation(s)
- Martin Pollak
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
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63
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The structure of serum resistance-associated protein and its implications for human African trypanosomiasis. Nat Microbiol 2018; 3:295-301. [PMID: 29358741 DOI: 10.1038/s41564-017-0085-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 11/27/2017] [Indexed: 11/08/2022]
Abstract
Only two trypanosome subspecies are able to cause human African trypanosomiasis. To establish an infection in human blood, they must overcome the innate immune system by resisting the toxic effects of trypanolytic factor 1 and trypanolytic factor 2 (refs. 1,2). These lipoprotein complexes contain an active, pore-forming component, apolipoprotein L1 (ApoL1), that causes trypanosome cell death 3 . One of the two human-infective subspecies, Trypanosoma brucei rhodesiense, differs from non-infective trypanosomes solely by the presence of the serum resistance-associated protein, which binds directly to ApoL1 and blocks its pore-forming capacity3-5. Since this interaction is the single critical event that renders T. b. rhodesiense human- infective, detailed structural information that allows identification of binding determinants is crucial to understand immune escape by the parasite. Here, we present the structure of serum resistance-associated protein and reveal the adaptations that occurred as it diverged from other trypanosome surface molecules to neutralize ApoL1. We also present our mapping of residues important for ApoL1 binding, giving molecular insight into this interaction at the heart of human sleeping sickness.
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64
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Currier RB, Cooper A, Burrell-Saward H, MacLeod A, Alsford S. Decoding the network of Trypanosoma brucei proteins that determines sensitivity to apolipoprotein-L1. PLoS Pathog 2018; 14:e1006855. [PMID: 29346416 PMCID: PMC5790291 DOI: 10.1371/journal.ppat.1006855] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 01/30/2018] [Accepted: 01/05/2018] [Indexed: 12/27/2022] Open
Abstract
In contrast to Trypanosoma brucei gambiense and T. b. rhodesiense (the causative agents of human African trypanosomiasis), T. b. brucei is lysed by apolipoprotein-L1 (apoL1)-containing human serum trypanolytic factors (TLF), rendering it non-infectious to humans. While the mechanisms of TLF1 uptake, apoL1 membrane integration, and T. b. gambiense and T. b. rhodesiense apoL1-resistance have been extensively characterised, our understanding of the range of factors that drive apoL1 action in T. b. brucei is limited. Selecting our bloodstream-form T. b. brucei RNAi library with recombinant apoL1 identified an array of factors that supports the trypanocidal action of apoL1, including six putative ubiquitin modifiers and several proteins putatively involved in membrane trafficking; we also identified the known apoL1 sensitivity determinants, TbKIFC1 and the V-ATPase. Most prominent amongst the novel apoL1 sensitivity determinants was a putative ubiquitin ligase. Intriguingly, while loss of this ubiquitin ligase reduces parasite sensitivity to apoL1, its loss enhances parasite sensitivity to TLF1-dominated normal human serum, indicating that free and TLF1-bound apoL1 have contrasting modes-of-action. Indeed, loss of the known human serum sensitivity determinants, p67 (lysosomal associated membrane protein) and the cathepsin-L regulator, 'inhibitor of cysteine peptidase', had no effect on sensitivity to free apoL1. Our findings highlight a complex network of proteins that influences apoL1 action, with implications for our understanding of the anti-trypanosomal action of human serum.
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Affiliation(s)
- Rachel B. Currier
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Anneli Cooper
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | | | - Annette MacLeod
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Sam Alsford
- London School of Hygiene and Tropical Medicine, London, United Kingdom
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65
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Zhang X, Hong XK, Li SJ, Lai DH, Hide G, Lun ZR, Wen YZ. The effect of normal human serum on the mouse trypanosome Trypanosoma musculi in vitro and in vivo. Exp Parasitol 2017; 184:115-120. [PMID: 29246831 DOI: 10.1016/j.exppara.2017.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 11/07/2017] [Accepted: 12/11/2017] [Indexed: 12/12/2022]
Abstract
Trypanosoma musculi, a common blood flagellate found in mice, is similar in morphology and life cycle to the rat trypanosome T. lewisi. Both species belong to the subgenus Herpetosoma, and as T. lewisi has recently been shown to be a zoonotic pathogen, there is concern that T. musculi could also be potentially infective to humans. To test this hypothesis, a well-established method, the normal human serum (NHS) incubation test, was carried out which distinguishes human and non-human infective trypanosomes. We found that T. musculi could grow in 0.31% NHS in vitro, and even kept their infectivity to mice after incubation with 10% NHS for 24 h. In in vivo experiments, T. musculi were only slightly affected by NHS injection, confirming that it was less sensitive to the NHS than T. b. brucei, but more sensitive than T. lewisi. This resistance probably does not rely on a restricted uptake of ApoL-1. Due to this partial resistance, we cannot definitively confirm that T. musculi has the potential for infection to humans. As resistance is less than that of T. lewisi, our data suggest that it is unlikely to be a zoonotic pathogen although we would advise caution in the case of immunocompromised people such as AIDS and cancer patients.
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Affiliation(s)
- Xuan Zhang
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Xiao-Kun Hong
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Su-Jin Li
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - De-Hua Lai
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Geoff Hide
- Ecosystems and Environment Research Centre and Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, UK
| | - Zhao-Rong Lun
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China; Ecosystems and Environment Research Centre and Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, UK.
| | - Yan-Zi Wen
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China.
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67
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Kruzel-Davila E, Wasser WG, Skorecki K. APOL1 Nephropathy: A Population Genetics and Evolutionary Medicine Detective Story. Semin Nephrol 2017; 37:490-507. [PMID: 29110756 DOI: 10.1016/j.semnephrol.2017.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Common DNA sequence variants rarely have a high-risk association with a common disease. When such associations do occur, evolutionary forces must be sought, such as in the association of apolipoprotein L1 (APOL1) gene risk variants with nondiabetic kidney diseases in populations of African ancestry. The variants originated in West Africa and provided pathogenic resistance in the heterozygous state that led to high allele frequencies owing to an adaptive evolutionary selective sweep. However, the homozygous state is disadvantageous and is associated with a markedly increased risk of a spectrum of kidney diseases encompassing hypertension-attributed kidney disease, focal segmental glomerulosclerosis, human immunodeficiency virus nephropathy, sickle cell nephropathy, and progressive lupus nephritis. This scientific success story emerged with the help of the tools developed over the past 2 decades in human genome sequencing and population genomic databases. In this introductory article to a timely issue dedicated to illuminating progress in this area, we describe this unique population genetics and evolutionary medicine detective story. We emphasize the paradox of the inheritance mode, the missing heritability, and unresolved associations, including cardiovascular risk and diabetic nephropathy. We also highlight how genetic epidemiology elucidates mechanisms and how the principles of evolution can be used to unravel conserved pathways affected by APOL1 that may lead to novel therapies. The APOL1 gene provides a compelling example of a common variant association with common forms of nondiabetic kidney disease occurring in a continental population isolate with subsequent global admixture. Scientific collaboration using multiple experimental model systems and approaches should further clarify pathomechanisms further, leading to novel therapies.
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Affiliation(s)
| | - Walter G Wasser
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel; Department of Nephrology, Mayanei HaYeshua Medical Center, Bnei Brak, Israel
| | - Karl Skorecki
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel; Department of Genetics and Developmental Biology, Rappaport Faculty of Medicine and Research Institute Technion-Israel Institute of Technology, Rambam Health Care Campus, Haifa, Israel.
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Fontaine F, Lecordier L, Vanwalleghem G, Uzureau P, Van Reet N, Fontaine M, Tebabi P, Vanhollebeke B, Büscher P, Pérez-Morga D, Pays E. APOLs with low pH dependence can kill all African trypanosomes. Nat Microbiol 2017; 2:1500-1506. [PMID: 28924146 PMCID: PMC5660622 DOI: 10.1038/s41564-017-0034-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 08/24/2017] [Indexed: 02/02/2023]
Abstract
The primate-specific serum protein apolipoprotein L1 (APOL1) is the only secreted member of a family of cell death promoting proteins 1-4 . APOL1 kills the bloodstream parasite Trypanosoma brucei brucei, but not the human sleeping sickness agents T.b. rhodesiense and T.b. gambiense 3 . We considered the possibility that intracellular members of the APOL1 family, against which extracellular trypanosomes could not have evolved resistance, could kill pathogenic T. brucei subspecies. Here we show that recombinant APOL3 (rAPOL3) kills all African trypanosomes, including T.b. rhodesiense, T.b. gambiense and the animal pathogens Trypanosoma evansi, Trypanosoma congolense and Trypanosoma vivax. However, rAPOL3 did not kill more distant trypanosomes such as Trypanosoma theileri or Trypanosoma cruzi. This trypanolytic potential was partially shared by rAPOL1 from Papio papio (rPpAPOL1). The differential killing ability of rAPOL3 and rAPOL1 was associated with a distinct dependence on acidic pH for activity. Due both to its instability and toxicity when injected into mice, rAPOL3 cannot be used for the treatment of infection, but an experimental rPpAPOL1 mutant inspired by APOL3 exhibited enhanced trypanolytic activity in vitro and the ability to completely inhibit T.b. gambiense infection in mice. We conclude that pH dependence influences the trypanolytic potential of rAPOLs.
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Affiliation(s)
- Frédéric Fontaine
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium
| | - Laurence Lecordier
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium
| | - Gilles Vanwalleghem
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium.,School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Pierrick Uzureau
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium.,Laboratoire de Médecine Expérimentale (ULB222), Hôpital André Vésale, Université Libre de Bruxelles, 706, route de Gozée, B-6110, Montigny le Tilleul, Belgium
| | - Nick Van Reet
- Unit of Parasite Diagnostics, Institute of Tropical Medicine, 155, Nationalestraat, B-2000, Antwerpen, Belgium
| | - Martina Fontaine
- Laboratory of Immunobiology, IBMM, Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium
| | - Patricia Tebabi
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium
| | - Benoit Vanhollebeke
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium
| | - Philippe Büscher
- Unit of Parasite Diagnostics, Institute of Tropical Medicine, 155, Nationalestraat, B-2000, Antwerpen, Belgium
| | - David Pérez-Morga
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium.,Center for Microscopy and Molecular Imaging (CMMI), Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium
| | - Etienne Pays
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 12, rue des Profs Jeener et Brachet, B-6041, Gosselies, Belgium.
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Bruno J, Pozzi N, Oliva J, Edwards JC. Apolipoprotein L1 confers pH-switchable ion permeability to phospholipid vesicles. J Biol Chem 2017; 292:18344-18353. [PMID: 28918394 DOI: 10.1074/jbc.m117.813444] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 09/08/2017] [Indexed: 01/13/2023] Open
Abstract
Apolipoprotein L1 (ApoL1) is a human serum protein conferring resistance to African trypanosomes, and certain ApoL1 variants increase susceptibility to some progressive kidney diseases. ApoL1 has been hypothesized to function like a pore-forming colicin and has been reported to have permeability effects on both intracellular and plasma membranes. Here, to gain insight into how ApoL1 may function in vivo, we used vesicle-based ion permeability, direct membrane association, and intrinsic fluorescence to study the activities of purified recombinant ApoL1. We found that ApoL1 confers chloride-selective permeability to preformed phospholipid vesicles and that this selectivity is strongly pH-sensitive, with maximal activity at pH 5 and little activity above pH 7. When ApoL1 and lipid were allowed to interact at low pH and were then brought to neutral pH, chloride permeability was suppressed, and potassium permeability was activated. Both chloride and potassium permeability linearly correlated with the mass of ApoL1 in the reaction mixture, and both exhibited lipid selectivity, requiring the presence of negatively charged lipids for activity. Potassium, but not chloride, permease activity required the presence of calcium ions in both the association and activation steps. Direct assessment of ApoL1-lipid associations confirmed that ApoL1 stably associates with phospholipid vesicles, requiring low pH and the presence of negatively charged phospholipids for maximal binding. Intrinsic fluorescence of ApoL1 supported the presence of a significant structural transition when ApoL1 is mixed with lipids at low pH. This pH-switchable ion-selective permeability may explain the different effects of ApoL1 reported in intracellular and plasma membrane environments.
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Affiliation(s)
| | - Nicola Pozzi
- Biochemistry and Molecular Biology, Saint Louis University, St. Louis, Missouri 63110
| | - Jonathan Oliva
- Biochemistry and Molecular Biology, Saint Louis University, St. Louis, Missouri 63110
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Candidate gene polymorphisms study between human African trypanosomiasis clinical phenotypes in Guinea. PLoS Negl Trop Dis 2017; 11:e0005833. [PMID: 28827791 PMCID: PMC5595334 DOI: 10.1371/journal.pntd.0005833] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 09/12/2017] [Accepted: 07/25/2017] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Human African trypanosomiasis (HAT), a lethal disease induced by Trypanosoma brucei gambiense, has a range of clinical outcomes in its human host in West Africa: an acute form progressing rapidly to second stage, spontaneous self-cure and individuals able to regulate parasitaemia at very low levels, have all been reported from endemic foci. In order to test if this clinical diversity is influenced by host genetic determinants, the association between candidate gene polymorphisms and HAT outcome was investigated in populations from HAT active foci in Guinea. METHODOLOGY AND RESULTS Samples were collected from 425 individuals; comprising of 232 HAT cases, 79 subjects with long lasting positive and specific serology but negative parasitology and 114 endemic controls. Genotypes of 28 SNPs in eight genes passed quality control and were used for an association analysis. IL6 rs1818879 allele A (p = 0.0001, OR = 0.39, CI95 = [0.24-0.63], BONF = 0.0034) was associated with a lower risk of progressing from latent infection to active disease. MIF rs36086171 allele G seemed to be associated with an increased risk (p = 0.0239, OR = 1.65, CI95 = [1.07-2.53], BONF = 0.6697) but did not remain significant after Bonferroni correction. Similarly MIF rs12483859 C allele seems be associated with latent infections (p = 0.0077, OR = 1.86, CI95 = [1.18-2.95], BONF = 0.2157). We confirmed earlier observations that APOL1 G2 allele (DEL) (p = 0.0011, OR = 2.70, CI95 = [1.49-4.91], BONF = 0.0301) is associated with a higher risk and APOL1 G1 polymorphism (p = 0.0005, OR = 0.45, CI95 = [0.29-0.70], BONF = 0.0129) with a lower risk of developing HAT. No associations were found with other candidate genes. CONCLUSION Our data show that host genes are involved in modulating Trypanosoma brucei gambiense infection outcome in infected individuals from Guinea with IL6 rs1818879 being associated with a lower risk of progressing to active HAT. These results enhance our understanding of host-parasite interactions and, ultimately, may lead to the development of new control tools.
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71
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Madhavan SM, O'Toole JF, Konieczkowski M, Barisoni L, Thomas DB, Ganesan S, Bruggeman LA, Buck M, Sedor JR. APOL1 variants change C-terminal conformational dynamics and binding to SNARE protein VAMP8. JCI Insight 2017; 2:92581. [PMID: 28724794 DOI: 10.1172/jci.insight.92581] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 06/13/2017] [Indexed: 12/11/2022] Open
Abstract
APOL1 variants in African populations mediate resistance to trypanosomal infection but increase risk for kidney diseases through unknown mechanisms. APOL1 is expressed in glomerular podocytes and does not vary with underlying kidney disease diagnoses or APOL1 genotypes, suggesting that the kidney disease-associated variants dysregulate its function rather than its localization or abundance. Structural homology searches identified vesicle-associated membrane protein 8 (VAMP8) as an APOL1 protein interactor. VAMP8 colocalizes with APOL1 in the podocyte, and the APOL1:VAMP8 interaction was confirmed biochemically and with surface plasmon resonance. APOL1 variants attenuate this interaction. Computational modeling of APOL1's 3-dimensional structure, followed by molecular dynamics simulations, revealed increased motion of the C-terminal domain of reference APOL1 compared with either variant, suggesting that the variants stabilize a closed or autoinhibited state that diminishes protein interactions with VAMP8. Changes in ellipticity with increasing urea concentrations, as assessed by circular dichroism spectroscopy, showed higher conformational stability of the C-terminal helix of the variants compared with the reference protein. These results suggest that reference APOL1 interacts with VAMP8-coated vesicles, a process attenuated by variant-induced reduction in local dynamics of the C-terminal. Disordered vesicular trafficking in the podocyte may cause injury and progressive chronic kidney diseases in susceptible African Americans subjects.
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Affiliation(s)
- Sethu M Madhavan
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and
| | - John F O'Toole
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and
| | - Martha Konieczkowski
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and
| | - Laura Barisoni
- Department of Pathology, University of Miami, Miami, Florida, USA
| | - David B Thomas
- Department of Pathology, University of Miami, Miami, Florida, USA
| | | | - Leslie A Bruggeman
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and
| | - Matthias Buck
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - John R Sedor
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and.,Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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Granado D, Müller D, Krausel V, Kruzel-Davila E, Schuberth C, Eschborn M, Wedlich-Söldner R, Skorecki K, Pavenstädt H, Michgehl U, Weide T. Intracellular APOL1 Risk Variants Cause Cytotoxicity Accompanied by Energy Depletion. J Am Soc Nephrol 2017; 28:3227-3238. [PMID: 28696248 DOI: 10.1681/asn.2016111220] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 05/24/2017] [Indexed: 12/17/2022] Open
Abstract
Population genetic approaches have uncovered a strong association between kidney diseases and two sequence variants of the APOL1 gene, called APOL1 risk variant G1 and variant G2, compared with the nonrisk G0 allele. However, the mechanism whereby these variants lead to disease manifestation and, in particular, whether this involves an intracellular or extracellular pool of APOL1 remains unclear. Herein, we show a predominantly intracellular localization of APOL1 G0 and the renal risk variants, which localized to membranes of the endoplasmic reticulum in podocyte cell lines. This localization did not depend on the N-terminal signal peptide that mediates APOL1 secretion into the circulation. Additionally, a fraction of these proteins localized to structures surrounding mitochondria. In vitro overexpression of G1 or G2 lacking the signal peptide inhibited cell viability, triggered phosphorylation of stress-induced kinases, increased the phosphorylation of AMP-activated protein kinase, reduced intracellular potassium levels, and reduced mitochondrial respiration rates. These findings indicate that functions at intracellular membranes, specifically those of the endoplasmic reticulum and mitochondria, are crucial factors in APOL1 renal risk variant-mediated cell injury.
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Affiliation(s)
| | | | | | | | - Christian Schuberth
- Institute of Cell Dynamics and Imaging, and Cells in Motion (CiM) Cluster of Excellence (EXC1003), University of Münster, Münster, Germany; and
| | - Melanie Eschborn
- Department of Neurology, University Hospital of Münster, Münster, Germany
| | - Roland Wedlich-Söldner
- Institute of Cell Dynamics and Imaging, and Cells in Motion (CiM) Cluster of Excellence (EXC1003), University of Münster, Münster, Germany; and
| | - Karl Skorecki
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel.,Departments of Genetics and Developmental Biology, Rappaport Faculty of Medicine and Research Institute, Technion, Israel Institute of Technology, Haifa, Israel
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Dewachter L, Verstraeten N, Jennes M, Verbeelen T, Biboy J, Monteyne D, Pérez-Morga D, Verstrepen KJ, Vollmer W, Fauvart M, Michiels J. A Mutant Isoform of ObgE Causes Cell Death by Interfering with Cell Division. Front Microbiol 2017; 8:1193. [PMID: 28702018 PMCID: PMC5487468 DOI: 10.3389/fmicb.2017.01193] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 06/12/2017] [Indexed: 01/14/2023] Open
Abstract
Cell division is a vital part of the cell cycle that is fundamental to all life. Despite decades of intense investigation, this process is still incompletely understood. Previously, the essential GTPase ObgE, which plays a role in a myriad of basic cellular processes (such as initiation of DNA replication, chromosome segregation, and ribosome assembly), was proposed to act as a cell cycle checkpoint in Escherichia coli by licensing chromosome segregation. We here describe the effect of a mutant isoform of ObgE (ObgE∗) that causes cell death by irreversible arrest of the cell cycle at the stage of cell division. Notably, chromosome segregation is allowed to proceed normally in the presence of ObgE∗, after which cell division is blocked. Under conditions of rapid growth, ongoing cell cycles are completed before cell cycle arrest by ObgE∗ becomes effective. However, cell division defects caused by ObgE∗ then elicit lysis through formation of membrane blebs at aberrant division sites. Based on our results, and because ObgE was previously implicated in cell cycle regulation, we hypothesize that the mutation in ObgE∗ disrupts the normal role of ObgE in cell division. We discuss how ObgE∗ could reveal more about the intricate role of wild-type ObgE in division and cell cycle control. Moreover, since Obg is widely conserved and essential for viability, also in eukaryotes, our findings might be applicable to other organisms as well.
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Affiliation(s)
- Liselot Dewachter
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
| | - Natalie Verstraeten
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
| | - Michiel Jennes
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
| | - Tom Verbeelen
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Daniel Monteyne
- Laboratory of Molecular Parasitology, Institut de Biologie et de Médecine Moléculaires, Université Libre de BruxellesGosselies, Belgium
| | - David Pérez-Morga
- Laboratory of Molecular Parasitology, Institut de Biologie et de Médecine Moléculaires, Université Libre de BruxellesGosselies, Belgium.,Center for Microscopy and Molecular Imaging, Université Libre de BruxellesGosselies, Belgium
| | - Kevin J Verstrepen
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium.,Systems Biology Laboratory, VIB Center for MicrobiologyLeuven, Belgium
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium.,Department of Life Sciences and Imaging, Smart Electronics Unit, ImecLeuven, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
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Cooper A, Ilboudo H, Alibu VP, Ravel S, Enyaru J, Weir W, Noyes H, Capewell P, Camara M, Milet J, Jamonneau V, Camara O, Matovu E, Bucheton B, MacLeod A. APOL1 renal risk variants have contrasting resistance and susceptibility associations with African trypanosomiasis. eLife 2017; 6. [PMID: 28537557 PMCID: PMC5495568 DOI: 10.7554/elife.25461] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 05/22/2017] [Indexed: 12/17/2022] Open
Abstract
Reduced susceptibility to infectious disease can increase the frequency of otherwise deleterious alleles. In populations of African ancestry, two apolipoprotein-L1 (APOL1) variants with a recessive kidney disease risk, named G1 and G2, occur at high frequency. APOL1 is a trypanolytic protein that confers innate resistance to most African trypanosomes, but not Trypanosoma brucei rhodesiense or T.b. gambiense, which cause human African trypanosomiasis. In this case-control study, we test the prevailing hypothesis that these APOL1 variants reduce trypanosomiasis susceptibility, resulting in their positive selection in sub-Saharan Africa. We demonstrate a five-fold dominant protective association for G2 against T.b. rhodesiense infection. Furthermore, we report unpredicted strong opposing associations with T.b. gambiense disease outcome. G2 associates with faster progression of T.b. gambiense trypanosomiasis, while G1 associates with asymptomatic carriage and undetectable parasitemia. These results implicate both forms of human African trypanosomiasis in the selection and persistence of otherwise detrimental APOL1 kidney disease variants. DOI:http://dx.doi.org/10.7554/eLife.25461.001 African-Americans have a greater risk of developing chronic kidney disease than Americans with European ancestry. Much of this increased risk is explained by two versions of a gene called APOL1 that are common in people with African ancestry. These two versions of the gene, known as G1 and G2, suddenly became much more common in people in sub-Saharan Africa in the last 10,000 years. One theory for their rapid spread is that they might protect against a deadly parasitic disease known as African sleeping sickness. This disease is caused by two related parasites of a species known as Trypanosoma brucei, one of which is found in East Africa, while the other affects West Africa. Laboratory studies have shown that blood from individuals who carry the G1 and G2 variants is better at killing the East African parasites. However, it is not clear if these gene versions help people living in the rural communities, where African sleeping sickness is common, to fight off the disease. Now, Cooper, Ilboudo et al. show that G1 and G2 do indeed influence how susceptible individuals in these communities are to African sleeping sickness. Individuals with the G2 version were five-times less likely to get the disease from the East African parasite. Neither version could protect individuals from infection with the West African parasite, but infected individuals with the G1 version had fewer parasites in their blood and were less likely to become severely ill. The ability of the G1 version to control the disease and prolong life could explain why this gene version has become so common amongst people in West Africa. Unexpectedly, the experiments also revealed that people with the G2 version were more likely to become severely unwell when they were infected by the West African parasite. This indicates that whether this gene variant is helpful or harmful depends on where an individual lives. The next step following on from this work will be to investigate exactly how the G1 version reduces the severity of the West African disease. This may aid the development of new drugs for African sleeping sickness and kidney disease. DOI:http://dx.doi.org/10.7554/eLife.25461.002
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Affiliation(s)
- Anneli Cooper
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Hamidou Ilboudo
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso.,TrypanoGEN, H3Africa Consortium, Makerere University, Kampala, Uganda
| | - V Pius Alibu
- TrypanoGEN, H3Africa Consortium, Makerere University, Kampala, Uganda.,College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Sophie Ravel
- Unité Mixte de Recherche IRD-CIRAD 177, Institut de Recherche pour le Développement, Montpellier, France
| | - John Enyaru
- TrypanoGEN, H3Africa Consortium, Makerere University, Kampala, Uganda.,College of Natural Sciences, Makerere University, Kampala, Uganda
| | - William Weir
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Harry Noyes
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.,TrypanoGEN, H3Africa Consortium, Makerere University, Kampala, Uganda.,Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Paul Capewell
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Mamadou Camara
- TrypanoGEN, H3Africa Consortium, Makerere University, Kampala, Uganda.,Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Conakry, Guinea
| | - Jacqueline Milet
- Unité Mixte de Recherche IRD-CIRAD 177, Institut de Recherche pour le Développement, Montpellier, France
| | - Vincent Jamonneau
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso.,TrypanoGEN, H3Africa Consortium, Makerere University, Kampala, Uganda.,Unité Mixte de Recherche IRD-CIRAD 177, Institut de Recherche pour le Développement, Montpellier, France
| | - Oumou Camara
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Conakry, Guinea
| | - Enock Matovu
- TrypanoGEN, H3Africa Consortium, Makerere University, Kampala, Uganda.,College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Bruno Bucheton
- TrypanoGEN, H3Africa Consortium, Makerere University, Kampala, Uganda.,Unité Mixte de Recherche IRD-CIRAD 177, Institut de Recherche pour le Développement, Montpellier, France.,Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Conakry, Guinea
| | - Annette MacLeod
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.,TrypanoGEN, H3Africa Consortium, Makerere University, Kampala, Uganda
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75
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Cooper C, Thompson RCA, Botero A, Kristancic A, Peacock C, Kirilak Y, Clode PL. A comparative molecular and 3-dimensional structural investigation into cross-continental and novel avian Trypanosoma spp. in Australia. Parasit Vectors 2017; 10:234. [PMID: 28499405 PMCID: PMC5427604 DOI: 10.1186/s13071-017-2173-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/03/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Molecular and structural information on avian Trypanosoma spp. throughout Australia is limited despite their intrinsic value in understanding trypanosomatid evolution, diversity, and structural biology. In Western Australia tissue samples (n = 429) extracted from 93 birds in 25 bird species were screened using generic PCR primers to investigate the diversity of Trypanosoma spp. To investigate avian trypanosome structural biology the first 3-dimensional ultrastructural models of a Trypanosoma spp. (Trypanosoma sp. AAT) isolated from a bird (currawong, Strepera spp.) were generated using focussed ion beam milling combined with scanning electron microscopy (FIB-SEM). RESULTS Here, we confirm four intercontinental species of avian trypanosomes in native Australian birds, and identify a new avian Trypanosoma. Trypanosome infection was identified in 18 birds from 13 different bird species (19%). A single new genotype was isolated and found to be closely related to T. culicavium (Trypanosoma sp. CC2016 B002). Other Trypanosoma spp. identified include T. avium, T. culicavium, T. thomasbancrofti, Trypanosoma sp. TL.AQ.22, Trypanosoma sp. AAT, and an uncharacterised Trypanosoma sp. (group C-III sensu Zidková et al. (Infect Genet Evol 12:102-112, 2012)), all previously identified in Australia or other continents. Serially-sectioning Trypanosoma sp. AAT epimastigotes using FIB-SEM revealed the disc-shaped kinetoplast pocket attached perpendicular to the branching mitochondrion. Additionally, the universal minicircle sequence within the kinetoplast DNA and the associated binding protein were determined in Trypanosoma sp. AAT. CONCLUSIONS These results indicate that bird trypanosomes are relatively conserved across continents, while being locally diverse, which supports the hypothesis that bird trypanosomes exist as fewer species than described in the literature. Evidence exists that avian Trypanosoma spp. are infecting mammals and could be transmitted by haemadipsid leeches. Trypanosoma sp. AAT is most likely a separate species currently found only in Australia and the first 3-dimentional ultrastructural analysis of an avian trypanosome provides interesting information on their morphology and organelle arrangement.
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Affiliation(s)
- Crystal Cooper
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA 6009 Australia
| | - R. C. Andrew Thompson
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
| | - Adriana Botero
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
| | - Amanda Kristancic
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
| | - Christopher Peacock
- Marshall Centre, School of Pathology and Laboratory and Medical Sciences, University of Western Australia, Crawley, WA 6009 Australia
- Telethon Kids Institute, 100 Roberts Rd, Subiaco, WA 6008 Australia
| | - Yaowanuj Kirilak
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA 6009 Australia
| | - Peta L. Clode
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA 6009 Australia
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76
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Dynamin-like proteins in Trypanosoma brucei: A division of labour between two paralogs? PLoS One 2017; 12:e0177200. [PMID: 28481934 PMCID: PMC5421789 DOI: 10.1371/journal.pone.0177200] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 04/24/2017] [Indexed: 11/19/2022] Open
Abstract
Dynamins and dynamin-like proteins (DLPs) belong to a family of large GTPases involved in membrane remodelling events. These include both fusion and fission processes with different dynamin proteins often having a specialised function within the same organism. Trypanosoma brucei is thought to have only one multifunctional DLP (TbDLP). While this was initially reported to function in mitochondrial division only, an additional role in endocytosis and cytokinesis was later also proposed. Since there are two copies of TbDLP present in the trypanosome genome, we investigated potential functional differences between these two paralogs by re-expressing either protein in a TbDLP RNAi background. These paralogs, called TbDLP1 and TbDLP2, are almost identical bar a few amino acid substitutions. Our results, based on cell lines carrying tagged and RNAi-resistant versions of each protein, show that overexpression of TbDLP1 alone is able to rescue the observed endocytosis and growth defects in the mammalian bloodstream form (BSF) of the parasite. While TbDLP2 shows no rescue in our experiments in BSF, this might also be due to lower expression levels of the protein in this life stage. In contrast, both TbDLP proteins apparently play more complementary roles in the insect procyclic form (PCF) since neither TbDLP1 nor TbDLP2 alone can fully restore wildtype growth and morphology in TbDLP-depleted parasites.
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77
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A mouse recapitulating APOL1-associated kidney disease. Nat Med 2017; 23:411-412. [PMID: 28388606 DOI: 10.1038/nm.4318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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78
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Bruggeman LA, O'Toole JF, Sedor JR. Identifying the Intracellular Function of APOL1. J Am Soc Nephrol 2017; 28:1008-1011. [PMID: 28196842 DOI: 10.1681/asn.2016111262] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
| | | | - John R Sedor
- Department of Medicine, MetroHealth Medical Center and.,Department of Physiology, Case Western Reserve University School of Medicine, Cleveland, Ohio
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79
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Kruzel-Davila E, Shemer R, Ofir A, Bavli-Kertselli I, Darlyuk-Saadon I, Oren-Giladi P, Wasser WG, Magen D, Zaknoun E, Schuldiner M, Salzberg A, Kornitzer D, Marelja Z, Simons M, Skorecki K. APOL1-Mediated Cell Injury Involves Disruption of Conserved Trafficking Processes. J Am Soc Nephrol 2016; 28:1117-1130. [PMID: 27864431 DOI: 10.1681/asn.2016050546] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 10/05/2016] [Indexed: 01/08/2023] Open
Abstract
APOL1 harbors C-terminal sequence variants (G1 and G2), which account for much of the increased risk for kidney disease in sub-Saharan African ancestry populations. Expression of the risk variants has also been shown to cause injury to podocytes and other cell types, but the underlying mechanisms are not understood. We used Drosophila melanogaster and Saccharomyces cerevisiae to help clarify these mechanisms. Ubiquitous expression of the human APOL1 G1 and G2 disease risk alleles caused near-complete lethality in D. melanogaster, with no effect of the G0 nonrisk APOL1 allele, corresponding to the pattern of human disease risk. We also observed a congruent pattern of cellular damage with tissue-specific expression of APOL1. In particular, expression of APOL1 risk variants in D. melanogaster nephrocytes caused cell-autonomous accumulation of the endocytic tracer atrial natriuretic factor-red fluorescent protein at early stages and nephrocyte loss at later stages. We also observed differential toxicity of the APOL1 risk variants compared with the APOL1 nonrisk variants in S. cerevisiae, including impairment of vacuole acidification. Yeast strains defective in endosomal trafficking or organelle acidification but not those defective in autophagy displayed augmented APOL1 toxicity with all isoforms. This pattern of differential injury by the APOL1 risk alleles compared with the nonrisk alleles across evolutionarily divergent species is consistent with an impairment of conserved core intracellular endosomal trafficking processes. This finding should facilitate the identification of cell injury pathways and corresponding therapeutic targets of interest in these amenable experimental platforms.
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Affiliation(s)
- Etty Kruzel-Davila
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel; Departments of
| | | | - Ayala Ofir
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel; Departments of
| | - Ira Bavli-Kertselli
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel; Departments of
| | | | - Pazit Oren-Giladi
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel; Departments of
| | - Walter G Wasser
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel; Departments of.,Department of Nephrology, Mayanei HaYeshua Medical Center, Bnei Brak, Israel
| | - Daniella Magen
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel; Departments of.,Genetics and Developmental Biology and
| | | | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel; and
| | | | - Daniel Kornitzer
- Microbiology and Inflammation, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Zvonimir Marelja
- Imagine Institute, Paris Descartes University-Sorbonne Paris Cité, Paris, France
| | - Matias Simons
- Imagine Institute, Paris Descartes University-Sorbonne Paris Cité, Paris, France
| | - Karl Skorecki
- Department of Nephrology, Rambam Health Care Campus, Haifa, Israel; Departments of .,Genetics and Developmental Biology and
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80
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Ma L, Chou JW, Snipes JA, Bharadwaj MS, Craddock AL, Cheng D, Weckerle A, Petrovic S, Hicks PJ, Hemal AK, Hawkins GA, Miller LD, Molina AJA, Langefeld CD, Murea M, Parks JS, Freedman BI. APOL1 Renal-Risk Variants Induce Mitochondrial Dysfunction. J Am Soc Nephrol 2016; 28:1093-1105. [PMID: 27821631 DOI: 10.1681/asn.2016050567] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 08/12/2016] [Indexed: 11/03/2022] Open
Abstract
APOL1 G1 and G2 variants facilitate kidney disease in blacks. To elucidate the pathways whereby these variants contribute to disease pathogenesis, we established HEK293 cell lines stably expressing doxycycline-inducible (Tet-on) reference APOL1 G0 or the G1 and G2 renal-risk variants, and used Illumina human HT-12 v4 arrays and Affymetrix HTA 2.0 arrays to generate global gene expression data with doxycycline induction. Significantly altered pathways identified through bioinformatics analyses involved mitochondrial function; results from immunoblotting, immunofluorescence, and functional assays validated these findings. Overexpression of APOL1 by doxycycline induction in HEK293 Tet-on G1 and G2 cells led to impaired mitochondrial function, with markedly reduced maximum respiration rate, reserve respiration capacity, and mitochondrial membrane potential. Impaired mitochondrial function occurred before intracellular potassium depletion or reduced cell viability occurred. Analysis of global gene expression profiles in nondiseased primary proximal tubule cells from black patients revealed that the nicotinate phosphoribosyltransferase gene, responsible for NAD biosynthesis, was among the top downregulated transcripts in cells with two APOL1 renal-risk variants compared with those without renal-risk variants; nicotinate phosphoribosyltransferase also displayed gene expression patterns linked to mitochondrial dysfunction in HEK293 Tet-on APOL1 cell pathway analyses. These results suggest a pivotal role for mitochondrial dysfunction in APOL1-associated kidney disease.
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Affiliation(s)
- Lijun Ma
- Department of Internal Medicine, Section on Nephrology, .,Center for Public Health Genomics
| | - Jeff W Chou
- Center for Public Health Genomics.,Division of Public Health Sciences, Department of Biostatistical Sciences
| | | | - Manish S Bharadwaj
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine
| | | | - Dongmei Cheng
- Department of Internal Medicine, Section on Molecular Medicine
| | | | | | | | | | | | | | - Anthony J A Molina
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine
| | - Carl D Langefeld
- Center for Public Health Genomics.,Division of Public Health Sciences, Department of Biostatistical Sciences
| | - Mariana Murea
- Department of Internal Medicine, Section on Nephrology
| | - John S Parks
- Department of Internal Medicine, Section on Molecular Medicine
| | - Barry I Freedman
- Department of Internal Medicine, Section on Nephrology, .,Center for Public Health Genomics.,Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina
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81
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Cooper A, Capewell P, Clucas C, Veitch N, Weir W, Thomson R, Raper J, MacLeod A. A Primate APOL1 Variant That Kills Trypanosoma brucei gambiense. PLoS Negl Trop Dis 2016; 10:e0004903. [PMID: 27494254 PMCID: PMC4975595 DOI: 10.1371/journal.pntd.0004903] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 07/14/2016] [Indexed: 01/19/2023] Open
Abstract
Humans are protected against infection from most African trypanosomes by lipoprotein complexes present in serum that contain the trypanolytic pore-forming protein, Apolipoprotein L1 (APOL1). The human-infective trypanosomes, Trypanosoma brucei rhodesiense in East Africa and T. b. gambiense in West Africa have separately evolved mechanisms that allow them to resist APOL1-mediated lysis and cause human African trypanosomiasis, or sleeping sickness, in man. Recently, APOL1 variants were identified from a subset of Old World monkeys, that are able to lyse East African T. b. rhodesiense, by virtue of C-terminal polymorphisms in the APOL1 protein that hinder that parasite’s resistance mechanism. Such variants have been proposed as candidates for developing therapeutic alternatives to the unsatisfactory anti-trypanosomal drugs currently in use. Here we demonstrate the in vitro lytic ability of serum and purified recombinant protein of an APOL1 ortholog from the West African Guinea baboon (Papio papio), which is able to lyse examples of all sub-species of T. brucei including T. b. gambiense group 1 parasites, the most common agent of human African trypanosomiasis. The identification of a variant of APOL1 with trypanolytic ability for both human-infective T. brucei sub-species could be a candidate for universal APOL1-based therapeutic strategies, targeted against all pathogenic African trypanosomes. African trypanosomes are protozoan parasites that affect both humans and animals in poor rural areas of sub-Saharan Africa, and are a major constraint on health and agricultural development. Disease control is principally dependent on the administration of drugs, which are old and largely unsatisfactory. Humans are naturally resistant to infection by most African trypanosomes species because of a lytic protein component in their blood, called APOL1. However, human-infective trypanosomes, T. b. rhodesiense in East Africa, and T. b. gambiense in West Africa, have evolved separate mechanisms to disarm this lytic protein and cause disease. Recently, variants of APOL1 were discovered in some primates that are able to kill the East African human disease-causing sub-species. These APOL1 variants form the basis of current attempts to create novel therapeutic interventions that can kill both animal and human-infective trypanosomes. In this study, we show that another variant of the same protein from a West African baboon species is able to kill, not only East African human-infective trypanosomes, but also the West African parasites, which causes the majority of human African trypanosomiasis cases. This new APOL1 variant could be a potential candidate for anti-trypanosomal therapies targeted at all pathogenic trypanosome species.
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Affiliation(s)
- Anneli Cooper
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Paul Capewell
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Caroline Clucas
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Nicola Veitch
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - William Weir
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Russell Thomson
- Department of Medical Parasitology, Langone School of Medicine, New York University, New York, New York, United States of America
| | - Jayne Raper
- Department of Medical Parasitology, Langone School of Medicine, New York University, New York, New York, United States of America
| | - Annette MacLeod
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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82
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Environmental sensing by African trypanosomes. Curr Opin Microbiol 2016; 32:26-30. [DOI: 10.1016/j.mib.2016.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 04/12/2016] [Indexed: 11/15/2022]
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83
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Stijlemans B, Caljon G, Van Den Abbeele J, Van Ginderachter JA, Magez S, De Trez C. Immune Evasion Strategies of Trypanosoma brucei within the Mammalian Host: Progression to Pathogenicity. Front Immunol 2016; 7:233. [PMID: 27446070 PMCID: PMC4919330 DOI: 10.3389/fimmu.2016.00233] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/30/2016] [Indexed: 12/26/2022] Open
Abstract
The diseases caused by African trypanosomes (AT) are of both medical and veterinary importance and have adversely influenced the economic development of sub-Saharan Africa. Moreover, so far not a single field applicable vaccine exists, and chemotherapy is the only strategy available to treat the disease. These strictly extracellular protozoan parasites are confronted with different arms of the host's immune response (cellular as well as humoral) and via an elaborate and efficient (vector)-parasite-host interplay they have evolved efficient immune escape mechanisms to evade/manipulate the entire host immune response. This is of importance, since these parasites need to survive sufficiently long in their mammalian/vector host in order to complete their life cycle/transmission. Here, we will give an overview of the different mechanisms AT (i.e. T. brucei as a model organism) employ, comprising both tsetse fly saliva and parasite-derived components to modulate host innate immune responses thereby sculpturing an environment that allows survival and development within the mammalian host.
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Affiliation(s)
- Benoît Stijlemans
- Laboratory of Myeloid Cell Immunology, VIB Inflammation Research Center, Ghent, Belgium; Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Guy Caljon
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Wilrijk, Belgium; Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium
| | - Jan Van Den Abbeele
- Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM) , Antwerp , Belgium
| | - Jo A Van Ginderachter
- Laboratory of Myeloid Cell Immunology, VIB Inflammation Research Center, Ghent, Belgium; Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium; Department of Structural Biology, VIB, Brussels, Belgium
| | - Carl De Trez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium; Department of Structural Biology, VIB, Brussels, Belgium
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84
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Uzureau S, Coquerelle C, Vermeiren C, Uzureau P, Van Acker A, Pilotte L, Monteyne D, Acolty V, Vanhollebeke B, Van den Eynde B, Pérez-Morga D, Moser M, Pays E. Apolipoproteins L control cell death triggered by TLR3/TRIF signaling in dendritic cells. Eur J Immunol 2016; 46:1854-66. [PMID: 27198486 DOI: 10.1002/eji.201546252] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/04/2016] [Accepted: 05/12/2016] [Indexed: 02/01/2023]
Abstract
Apolipoproteins L (ApoLs) are Bcl-2-like proteins expressed under inflammatory conditions in myeloid and endothelial cells. We found that Toll-like receptor (TLR) stimuli, particularly the viral mimetic polyinosinic:polycytidylic acid (poly(I:C)), specifically induce ApoLs7/11 subfamilies in murine CD8α(+) dendritic cells (DCs). This induction requires the TLR3/TRIF (where TRIF is TIR domain containing adapter-inducing interferon β) signaling pathway and is dependent on IFN-β in all ApoLs subfamilies except for ApoL7c. Poly(I:C) treatment of DCs is also associated with induction of both cell death and autophagy. ApoLs expression is related to promotion of DC death by poly(I:C), as ApoLs7/11 knockdown increases DC survival and ApoLs7 are associated with the anti-apoptotic protein Bcl-xL (where Bcl-xL is B-cell lymphoma extra large). Similarly, in human monocyte-derived DCs poly(I:C) induces both cell death and the expression of ApoLs, principally ApoL3. Finally, the BH3-like peptide of ApoLs appears to be involved in the DC death-promoting activity. We would like to propose that ApoLs are involved in cell death linked to activation of DCs by viral stimuli.
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Affiliation(s)
- Sophie Uzureau
- Laboratoire de Parasitologie Moléculaire, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Caroline Coquerelle
- Laboratoire d'Immunobiologie, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Corentin Vermeiren
- Laboratoire de Parasitologie Moléculaire, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Pierrick Uzureau
- Laboratoire de Parasitologie Moléculaire, IBMM, Université Libre de Bruxelles, Gosselies, Belgium.,Laboratoire de Médecine Expérimentale, Hôpital Vésale, Université Libre de Bruxelles, Montigny-le-Tilleul, Belgium
| | - Annette Van Acker
- Laboratoire d'Immunobiologie, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Luc Pilotte
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Daniel Monteyne
- Laboratoire de Parasitologie Moléculaire, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Valérie Acolty
- Laboratoire d'Immunobiologie, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Benoit Vanhollebeke
- Laboratoire de Parasitologie Moléculaire, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | | | - David Pérez-Morga
- Laboratoire de Parasitologie Moléculaire, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Muriel Moser
- Laboratoire d'Immunobiologie, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Etienne Pays
- Laboratoire de Parasitologie Moléculaire, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
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85
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Abstract
African trypanosomes, except Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, which cause human African trypanosomiasis, are lysed by the human serum protein apolipoprotein L1 (ApoL1). These two subspecies can resist human ApoL1 because they express the serum resistance proteins T. b. gambiense glycoprotein (TgsGP) and serum resistance-associated protein (SRA), respectively. Whereas in T. b. rhodesiense, SRA is necessary and sufficient to inhibit ApoL1, in T. b. gambiense, TgsGP cannot protect against high ApoL1 uptake, so different additional mechanisms contribute to limit this uptake. Here we report a complex interplay between trypanosomes and an ApoL1 variant, revealing important insights into innate human immunity against these parasites. Using whole-genome sequencing, we characterized an atypical T. b. gambiense infection in a patient in Ghana. We show that the infecting trypanosome has diverged from the classical T. b. gambiense strains and lacks the TgsGP defense mechanism against human serum. By sequencing the ApoL1 gene of the patient and subsequent in vitro mutagenesis experiments, we demonstrate that a homozygous missense substitution (N264K) in the membrane-addressing domain of this ApoL1 variant knocks down the trypanolytic activity, allowing the trypanosome to avoid ApoL1-mediated immunity. Most African trypanosomes are lysed by the ApoL1 protein in human serum. Only the subspecies Trypanosoma b. gambiense and T. b. rhodesiense can resist lysis by ApoL1 because they express specific serum resistance proteins. We here report a complex interplay between trypanosomes and an ApoL1 variant characterized by a homozygous missense substitution (N264K) in the domain that we hypothesize interacts with the endolysosomal membranes of trypanosomes. The N264K substitution knocks down the lytic activity of ApoL1 against T. b. gambiense strains lacking the TgsGP defense mechanism and against T. b. rhodesiense if N264K is accompanied by additional substitutions in the SRA-interacting domain. Our data suggest that populations with high frequencies of the homozygous N264K ApoL1 variant may be at increased risk of contracting human African trypanosomiasis.
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86
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Friedman DJ, Pollak MR. Apolipoprotein L1 and Kidney Disease in African Americans. Trends Endocrinol Metab 2016; 27:204-215. [PMID: 26947522 PMCID: PMC4811340 DOI: 10.1016/j.tem.2016.02.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 02/06/2023]
Abstract
Genetic variants in the Apolipoprotein L1 (APOL1) gene cause high rates of kidney disease in African Americans. These variants, found only in individuals with recent African ancestry, confer enhanced innate immunity against African trypanosomes. Although they are among the most powerful disease-causing common variants discovered to date, we are just beginning to understand how they promote kidney injury. Since APOL1 is present in only a few primate species, much of our current knowledge has come from natural experiments in humans and in vitro studies while awaiting the development of transgenic animal models. Understanding more about the function of ApoL1 and how the high-risk variants behave differently from other ApoL1 molecules is a high priority in kidney disease research.
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Affiliation(s)
- David J. Friedman
- Beth Israel Deaconess Medical Center, Harvard Medical School, 99 Brookline Avenue, RN301, Boston, MA. 02215, 617 667 0253
| | - Martin R. Pollak
- Beth Israel Deaconess Medical Center, Harvard Medical School, 99 Brookline Avenue, RN325E, Boston, MA. 02215, 617 667 0461
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87
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Greene AS, Hajduk SL. Trypanosome Lytic Factor-1 Initiates Oxidation-stimulated Osmotic Lysis of Trypanosoma brucei brucei. J Biol Chem 2016; 291:3063-75. [PMID: 26645690 PMCID: PMC4742767 DOI: 10.1074/jbc.m115.680371] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 11/12/2015] [Indexed: 01/18/2023] Open
Abstract
Human innate immunity against the veterinary pathogen Trypanosoma brucei brucei is conferred by trypanosome lytic factors (TLFs), against which human-infective T. brucei gambiense and T. brucei rhodesiense have evolved resistance. TLF-1 is a subclass of high density lipoprotein particles defined by two primate-specific apolipoproteins: the ion channel-forming toxin ApoL1 (apolipoprotein L1) and the hemoglobin (Hb) scavenger Hpr (haptoglobin-related protein). The role of oxidative stress in the TLF-1 lytic mechanism has been controversial. Here we show that oxidative processes are involved in TLF-1 killing of T. brucei brucei. The lipophilic antioxidant N,N'-diphenyl-p-phenylenediamine protected TLF-1-treated T. brucei brucei from lysis. Conversely, lysis of TLF-1-treated T. brucei brucei was increased by the addition of peroxides or thiol-conjugating agents. Previously, the Hpr-Hb complex was postulated to be a source of free radicals during TLF-1 lysis. However, we found that the iron-containing heme of the Hpr-Hb complex was not involved in TLF-1 lysis. Furthermore, neither high concentrations of transferrin nor knock-out of cytosolic lipid peroxidases prevented TLF-1 lysis. Instead, purified ApoL1 was sufficient to induce lysis, and ApoL1 lysis was inhibited by the antioxidant DPPD. Swelling of TLF-1-treated T. brucei brucei was reminiscent of swelling under hypotonic stress. Moreover, TLF-1-treated T. brucei brucei became rapidly susceptible to hypotonic lysis. T. brucei brucei cells exposed to peroxides or thiol-binding agents were also sensitized to hypotonic lysis in the absence of TLF-1. We postulate that ApoL1 initiates osmotic stress at the plasma membrane, which sensitizes T. brucei brucei to oxidation-stimulated osmotic lysis.
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Affiliation(s)
- Amy Styer Greene
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Stephen L Hajduk
- From the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
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